Modeling Finite Faults Using the Adjoint Wave Field
NASA Astrophysics Data System (ADS)
Hjörleifsdóttir, V.; Liu, Q.; Tromp, J.
2004-12-01
Time-reversal acoustics, a technique in which an acoustic signal is recorded by an array of transducers, time-reversed, and retransmitted, is used, e.g., in medical therapy to locate and destroy gallstones (for a review see Fink, 1997). As discussed by Tromp et al. (2004), time-reversal techniques for locating sources are closely linked to so-called `adjoint methods' (Talagrand and Courtier, 1987), which may be used to evaluate the gradient of a misfit function. Tromp et al. (2004) illustrate how a (finite) source inversion may be implemented based upon the adjoint wave field by writing the change in the misfit function, δ χ, due to a change in the moment-density tensor, δ m, as an integral of the adjoint strain field ɛ x,t) over the fault plane Σ : δ χ = ∫ 0T∫_Σ ɛ x,T-t) :δ m(x,t) d2xdt. We find that if the real fault plane is located at a distance δ h in the direction of the fault normal hat n, then to first order an additional factor of ∫ 0T∫_Σ δ h (x) ∂ n ɛ x,T-t):m(x,t) d2xdt is added to the change in the misfit function. The adjoint strain is computed by using the time-reversed difference between data and synthetics recorded at all receivers as simultaneous sources and recording the resulting strain on the fault plane. In accordance with time-reversal acoustics, all the resulting waves will constructively interfere at the position of the original source in space and time. The level of convergence will be deterimined by factors such as the source-receiver geometry, the frequency of the recorded data and synthetics, and the accuracy of the velocity structure used when back propagating the wave field. The terms ɛ x,T-t) and ∂ n ɛ x,T-t):m(x,t) can be viewed as sensitivity kernels for the moment density and the faultplane location respectively. By looking at these quantities we can make an educated choice of fault parametrization given the data in hand. The process can then be repeated to invert for the best source model, as
Nonsingular cosmology from an unstable Higgs field
NASA Astrophysics Data System (ADS)
Brandenberger, Robert H.; Cai, Yi-Fu; Wan, Youping; Zhang, Xinmin
The observed value of the Higgs mass indicates an instability of the Higgs scalar at large energy scales, and hence also at large field values. In the context of early universe cosmology, this is often considered to lead to problems. Here, we point out that we can use the instability of the Higgs field to generate an ekpyrotic phase of contraction. In the context of string theory, it is possible that at very high energy densities, extra states become massless leading to an S-brane which causes the transition between a contracting phase in the past and the current expanding phase. Thus, the Higgs field may be useable to generate a nonsingular bouncing cosmology in which the anisotropy problem of usual bouncing scenarios is mitigated.
Introduction to Adjoint Models
NASA Technical Reports Server (NTRS)
Errico, Ronald M.
2015-01-01
In this lecture, some fundamentals of adjoint models will be described. This includes a basic derivation of tangent linear and corresponding adjoint models from a parent nonlinear model, the interpretation of adjoint-derived sensitivity fields, a description of methods of automatic differentiation, and the use of adjoint models to solve various optimization problems, including singular vectors. Concluding remarks will attempt to correct common misconceptions about adjoint models and their utilization.
Adjoint-field errors in high fidelity compressible turbulence simulations for sound control
NASA Astrophysics Data System (ADS)
Vishnampet, Ramanathan; Bodony, Daniel; Freund, Jonathan
2013-11-01
A consistent discrete adjoint for high-fidelity discretization of the three-dimensional Navier-Stokes equations is used to quantify the error in the sensitivity gradient predicted by the continuous adjoint method, and examine the aeroacoustic flow-control problem for free-shear-flow turbulence. A particular quadrature scheme for approximating the cost functional makes our discrete adjoint formulation for a fourth-order Runge-Kutta scheme with high-order finite differences practical and efficient. The continuous adjoint-based sensitivity gradient is shown to to be inconsistent due to discretization truncation errors, grid stretching and filtering near boundaries. These errors cannot be eliminated by increasing the spatial or temporal resolution since chaotic interactions lead them to become O (1) at the time of control actuation. Although this is a known behavior for chaotic systems, its effect on noise control is much harder to anticipate, especially given the different resolution needs of different parts of the turbulence and acoustic spectra. A comparison of energy spectra of the adjoint pressure fields shows significant error in the continuous adjoint at all wavenumbers, even though they are well-resolved. The effect of this error on the noise control mechanism is analyzed.
Effective field theory analysis of Higgs naturalness
Bar-Shalom, Shaouly; Soni, Amarjit; Wudka, Jose
2015-07-20
Assuming the presence of physics beyond the Standard Model ( SM) with a characteristic scale M ~ O (10) TeV, we investigate the naturalness of the Higgs sector at scales below M using an effective field theory (EFT) approach. We obtain the leading 1 -loop EFT contributions to the Higgs mass with a Wilsonian-like hard cutoff, and determine t he constraints on the corresponding operator coefficients for these effects to alleviate the little hierarchy problem up to the scale of the effective action Λ < M , a condition we denote by “EFT-naturalness”. We also determine the types of physics that can lead to EFT-naturalness and show that these types of new physics are best probed in vector-boson and multiple-Higgs production. The current experimental constraints on these coefficients are also discussed.
Inversion of Gravity Fields From the Spacecraft Orbital Data Using an Adjoint Operator Approach
NASA Technical Reports Server (NTRS)
Ustinov, E. A.
1999-01-01
In perturbation approximation, the forward problem of orbital dynamics (equations with initial conditions) is linear with respect to variations of coordinates and/or velocities of the spacecraft and to corresponding variations of the gravity field in the models used. The linear operator adjoint to the linear operator of such forward problem turns out to be instrumental in inversion of differences between observed and predicted coordinates/velocities in terms of the updates of harmonics in the initial gravity field model. Based on this approach, the solution of resulting adjoint problem of orbital dynamics can be used to directly evaluate the matrix of partial derivatives of observable differences with respect to the gravity field harmonics. General discussion of the adjoint problem of orbital dynamics is given and an example of a mathematical formalism for the practical retrieval algorithm is presented.
Scalar field dark matter and the Higgs field
NASA Astrophysics Data System (ADS)
Bertolami, O.; Cosme, Catarina; Rosa, João G.
2016-08-01
We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10-6-10-4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall-Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.
Self-adjointness of the Fourier expansion of quantized interaction field Lagrangians
Paneitz, S. M.; Segal, I. E.
1983-01-01
Regularity properties significantly stronger than were previously known are developed for four-dimensional non-linear conformally invariant quantized fields. The Fourier coefficients of the interaction Lagrangian in the interaction representation—i.e., evaluated after substitution of the associated quantized free field—is a densely defined operator on the associated free field Hilbert space K. These Fourier coefficients are with respect to a natural basis in the universal cosmos ˜M, to which such fields canonically and maximally extend from Minkowski space-time M0, which is covariantly a submanifold of ˜M. However, conformally invariant free fields over M0 and ˜M are canonically identifiable. The kth Fourier coefficient of the interaction Lagrangian has domain inclusive of all vectors in K to which arbitrary powers of the free hamiltonian in ˜M are applicable. Its adjoint in the rigorous Hilbert space sense is a-k in the case of a hermitian Lagrangian. In particular (k = 0) the leading term in the perturbative expansion of the S-matrix for a conformally invariant quantized field in M0 is a self-adjoint operator. Thus, e.g., if ϕ(x) denotes the free massless neutral scalar field in M0, then ∫M0:ϕ(x)4:d4x is a self-adjoint operator. No coupling constant renormalization is involved here. PMID:16593346
The adjoint-state method for the downward continuation of the geomagnetic field
NASA Astrophysics Data System (ADS)
Hagedoorn, J. M.; Martinec, Z.
2015-05-01
The downward continuation of the observed geomagnetic field from the Earth's surface to the core-mantle boundary (CMB) is complicated due to induction and diffusion processes in the electrically conducting Earth mantle, which modify the amplitudes and morphology of the geomagnetic field. Various methods have been developed to solve this problem, for example, the perturbation approach by Benton & Whaler, or the non-harmonic downward continuation by Ballani et al. In this paper, we present a new approach for determining the geomagnetic field at the CMB by reformulating the ill-posed, one-sided boundary-value problem with time-variable boundary-value function on the Earth's surface into an optimization problem for the boundary condition at the CMB. The reformulated well-posed problem is solved by a conjugate gradient technique using the adjoint gradient of a misfit. For this purpose, we formulate the geomagnetic adjoint-state equations for efficient computations of the misfit gradient. Beside the theoretical description of the new adjoint-state method (ASM), the first applications to a global geomagnetic field model are presented. The comparison with other methods demonstrates the capability of the new method to determine the geomagnetic field at the CMB and allows us to investigate the variability of the determined field with respect to the applied methods. This shows that it is necessary to apply the ASM when investigating the effect of the Earth's mantle conductivity because the difference between the results of approximate methods (harmonic downward continuation, perturbation approach) and the rigorous ASM are of the same order as the difference between the results of the ASM applied for different mantle conductivities.
Magnetic Field Separation Around Planets Using an Adjoint-Method Approach
NASA Astrophysics Data System (ADS)
Nabert, Christian; Glassmeier, Karl-Heinz; Heyner, Daniel; Othmer, Carsten
The two spacecraft of the BepiColombo mission will reach planet Mercury in 2022. The magnetometers on-board these polar orbiting spacecraft will provide a detailed map of the magnetic field in Mercury's environment. Unfortunately, a separation of the magnetic field into internal and external parts using the classical Gauss-algorithm is not possible due to strong electric currents in the orbit region of the spacecraft. These currents are due to the interaction of the solar wind with Mercury's planetary magnetic field. We use an MHD code to simulate this interaction process. This requires a first choice of Mercury's planetary field which is used and modified until the simulation results fit to the actual measurements. This optimization process is carried out most efficiently using an adjoint-method. The adjoint-method is well known for its low computational cost in order to determine sensitivities required for the minimization. In a first step, the validity of our approach to separate magnetic field contributions into internal and external parts is demonstrated using synthetic generated data. Furthermore, we apply our approach to satellite measurements of the Earth's magnetic field. We can compare the results with the well known planetary field of the Earth to prove practical suitability.
Optimization of computations for adjoint field and Jacobian needed in 3D CSEM inversion
NASA Astrophysics Data System (ADS)
Dehiya, Rahul; Singh, Arun; Gupta, Pravin K.; Israil, M.
2017-01-01
We present the features and results of a newly developed code, based on Gauss-Newton optimization technique, for solving three-dimensional Controlled-Source Electromagnetic inverse problem. In this code a special emphasis has been put on representing the operations by block matrices for conjugate gradient iteration. We show how in the computation of Jacobian, the matrix formed by differentiation of system matrix can be made independent of frequency to optimize the operations at conjugate gradient step. The coarse level parallel computing, using OpenMP framework, is used primarily due to its simplicity in implementation and accessibility of shared memory multi-core computing machine to almost anyone. We demonstrate how the coarseness of modeling grid in comparison to source (comp`utational receivers) spacing can be exploited for efficient computing, without compromising the quality of the inverted model, by reducing the number of adjoint calls. It is also demonstrated that the adjoint field can even be computed on a grid coarser than the modeling grid without affecting the inversion outcome. These observations were reconfirmed using an experiment design where the deviation of source from straight tow line is considered. Finally, a real field data inversion experiment is presented to demonstrate robustness of the code.
Usefulness of effective field theory for boosted Higgs production
Dawson, S.; Lewis, I. M.; Zeng, Mao
2015-04-07
The Higgs + jet channel at the LHC is sensitive to the effects of new physics both in the total rate and in the transverse momentum distribution at high _{pT}. We examine the production process using an effective field theory (EFT) language and discussing the possibility of determining the nature of the underlying high-scale physics from boosted Higgs production. The effects of heavy color triplet scalars and top partner fermions with TeV scale masses are considered as examples and Higgs-gluon couplings of dimension-5 and dimension-7 are included in the EFT. As a byproduct of our study, we examine the region of validity of the EFT. Dimension-7 contributions in realistic new physics models give effects in the high _{pT} tail of the Higgs signal which are so tiny that they are likely to be unobservable.
Did the universe start with the Higgs-field?
NASA Astrophysics Data System (ADS)
Lessner, G.
2013-02-01
In a cosmological model developed by the author in previous articles the universe starts in a geometrical phase transition in Minkowski space. Here the source of the gravitational field is a Higgs-like scalar field bar{φ}. A relation of this cosmological field bar{φ} with the Higgs-field ϕ H in the gauge theory of electroweak interaction is established. This relation leads to two dimensionless constants. One of them is interpreted as a characteristic constant of the phase transition and is connected with the volume of huge bubbles of open universes.
NASA Astrophysics Data System (ADS)
Ito, Shin-Ichi; Nagao, Hiromichi; Yamanaka, Akinori; Tsukada, Yuhki; Koyama, Toshiyuki; Inoue, Junya
Phase field (PF) method, which phenomenologically describes dynamics of microstructure evolutions during solidification and phase transformation, has progressed in the fields of hydromechanics and materials engineering. How to determine, based on observation data, an initial state and model parameters involved in a PF model is one of important issues since previous estimation methods require too much computational cost. We propose data assimilation (DA), which enables us to estimate the parameters and states by integrating the PF model and observation data on the basis of the Bayesian statistics. The adjoint method implemented on DA not only finds an optimum solution by maximizing a posterior distribution but also evaluates the uncertainty in the estimations by utilizing the second order information of the posterior distribution. We carried out an estimation test using synthetic data generated by the two-dimensional Kobayashi's PF model. The proposed method is confirmed to reproduce the true initial state and model parameters we assume in advance, and simultaneously estimate their uncertainties due to quality and quantity of the data. This result indicates that the proposed method is capable of suggesting the experimental design to achieve the required accuracy.
Gardner, Adam R.; Hayakawa, Carole K.; Venugopalan, Vasan
2014-01-01
Abstract. We present a coupled forward-adjoint Monte Carlo (cFAMC) method to determine the spatially resolved sensitivity distributions produced by optical interrogation of three-dimensional (3-D) tissue volumes. We develop a general computational framework that computes the spatial and angular distributions of the forward-adjoint light fields to provide accurate computations in mesoscopic tissue volumes. We provide full computational details of the cFAMC method and provide results for low- and high-scattering tissues probed using a single pair of optical fibers. We examine the effects of source-detector separation and orientation on the sensitivity distributions and consider how the degree of angular discretization used in the 3-D tissue model impacts the accuracy of the resulting absorption sensitivity profiles. We discuss the value of such computations for optical imaging and the design of optical measurements. PMID:24972356
Gavrilov, S.P.; Gitman, D.M.; Smirnov, A.A.
2003-02-01
We study solutions of Dirac equation in the field of Aharonov-Bohm solenoid and a collinear uniform magnetic field. On this base we construct self-adjoint extensions of the Dirac Hamiltonian using von Neumann's theory of deficiency indices. We reduce (3+1)-dimensional problem to (2+1)-dimensional one by a proper choice of spin operator. Then we study the problem doing a finite radius regularization of the solenoid field. We exploit solutions of the latter problem to specify boundary conditions in the singular case.
NASA Technical Reports Server (NTRS)
Ustinov, Eugene A.; Sunseri, Richard F.
2005-01-01
An approach is presented to the inversion of gravity fields based on evaluation of partials of observables with respect to gravity harmonics using the solution of adjoint problem of orbital dynamics of the spacecraft. Corresponding adjoint operator is derived directly from the linear operator of the linearized forward problem of orbital dynamics. The resulting adjoint problem is similar to the forward problem and can be solved by the same methods. For given highest degree N of gravity harmonics desired, this method involves integration of N adjoint solutions as compared to integration of N2 partials of the forward solution with respect to gravity harmonics in the conventional approach. Thus, for higher resolution gravity models, this approach becomes increasingly more effective in terms of computer resources as compared to the approach based on the solution of the forward problem of orbital dynamics.
Gauge mediation models with adjoint messengers
NASA Astrophysics Data System (ADS)
Gogoladze, Ilia; Mustafayev, Azar; Shafi, Qaisar; Ün, Cem Salih
2016-10-01
We present a class of models in the framework of gauge mediation supersymmetry breaking where the messenger fields transform in the adjoint representation of the standard model gauge symmetry. To avoid unacceptably light right-handed sleptons in the spectrum we introduce a nonzero U (1 )B-L D-term. This leads to an additional contribution to the soft supersymmetry breaking mass terms which makes the right-handed slepton masses compatible with the current experimental bounds. We show that in this framework the observed 125 GeV Higgs boson mass can be accommodated with the sleptons accessible at the LHC, while the squarks and gluinos lie in the multi-TeV range. We also discuss the issue of the fine-tuning and show that the desired relic dark matter abundance can also be accommodated.
Higgs criticality in a two-dimensional metal
NASA Astrophysics Data System (ADS)
Sachdev, Subir; Chowdhury, Debanjan
2015-03-01
We analyze a candidate theory for the strange metal near optimal hole-doping in the cuprate superconductors. The theory contains a quantum phase transition between metals with `large' and `small' Fermi surfaces, but the transition does not directly involve any broken global symmetries. The two metals have emergent SU(2) and U(1) gauge fields respectively, and the transition is driven by the condensation of a real Higgs field which carries an adjoint SU(2) charge. We propose a global phase diagram around this Higgs transition, and describe its relationship to a variety of recent experiments on the cuprate superconductors.
Precision Higgs Physics, Effective Field Theory, and Dark Matter
NASA Astrophysics Data System (ADS)
Henning, Brian Quinn
The recent discovery of the Higgs boson calls for detailed studies of its properties. As precision measurements are indirect probes of new physics, the appropriate theoretical framework is effective field theory. In the first part of this thesis, we present a practical three-step procedure of using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on the UV model concerned. We give a detailed explanation for calculating the effective action up to one-loop order in a manifestly gauge covariant fashion. The covariant derivative expansion dramatically simplifies the process of matching a UV model with the SM EFT, and also makes available a universal formalism that is easy to use for a variety of UV models. A few general aspects of renormalization group running effects and choosing operator bases are discussed. Finally, we provide mapping results between the bosonic sector of the SM EFT and a complete set of precision electroweak and Higgs observables to which present and near future experiments are sensitive. With a detailed understanding of how to use the SM EFT, we then turn to applications and study in detail two well-motivated test cases. The first is singlet scalar field that enables the first-order electroweak phase transition for baryogenesis; the second example is due to scalar tops in the MSSM. We find both Higgs and electroweak measurements are sensitive probes of these cases. The second part of this thesis centers around dark matter, and consists of two studies. In the first, we examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark
Self-adjointness of deformed unbounded operators
Much, Albert
2015-09-15
We consider deformations of unbounded operators by using the novel construction tool of warped convolutions. By using the Kato-Rellich theorem, we show that unbounded self-adjoint deformed operators are self-adjoint if they satisfy a certain condition. This condition proves itself to be necessary for the oscillatory integral to be well-defined. Moreover, different proofs are given for self-adjointness of deformed unbounded operators in the context of quantum mechanics and quantum field theory.
Yang-Mills Field as a Subset of Covariant Derivative -- a Unified Yang-Mills Field and Higgs Field
NASA Astrophysics Data System (ADS)
Gan, Woon Siong
2014-04-01
A different approach using the covariant derivative is used to derive the Yang-Mills field. This avoids the weakness of resulting massless particles. Covariant derivative is also used to derive the Higgs field. A detailed mass acquisition mechanism for matter particles and force particles is given for the Higgs field. This paves the way towards a unified Yang-Mills field and Higgs field. We show that the Yang-Mills field is a special case of the unified field when the temperature is above the critical temperature of the spontaneous symmetry breaking (SSB). SSB has a broader implication that it can be extended to all particles in the universe. Higgs boson is a product of SSB and it causes the Big Bang points to the role of SSB in the Big Bang creation of the universe and this gives support to the proposed superfluid model for the particles of the universe beyond the Standard Model. The critical temperature for SSB is equivalent to the extremely high temperature which occurs during the Big Bang.
Galanti, Eli; Kaspi, Yohai
2016-04-01
During 2016–17, the Juno and Cassini spacecraft will both perform close eccentric orbits of Jupiter and Saturn, respectively, obtaining high-precision gravity measurements for these planets. These data will be used to estimate the depth of the observed surface flows on these planets. All models to date, relating the winds to the gravity field, have been in the forward direction, thus only allowing the calculation of the gravity field from given wind models. However, there is a need to do the inverse problem since the new observations will be of the gravity field. Here, an inverse dynamical model is developed to relate the expected measurable gravity field, to perturbations of the density and wind fields, and therefore to the observed cloud-level winds. In order to invert the gravity field into the 3D circulation, an adjoint model is constructed for the dynamical model, thus allowing backward integration. This tool is used for the examination of various scenarios, simulating cases in which the depth of the wind depends on latitude. We show that it is possible to use the gravity measurements to derive the depth of the winds, both on Jupiter and Saturn, also taking into account measurement errors. Calculating the solution uncertainties, we show that the wind depth can be determined more precisely in the low-to-mid-latitudes. In addition, the gravitational moments are found to be particularly sensitive to flows at the equatorial intermediate depths. Therefore, we expect that if deep winds exist on these planets they will have a measurable signature by Juno and Cassini.
ERIC Educational Resources Information Center
Veltman, Martinus J. G.
1986-01-01
Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)
Higgs criticality in a two-dimensional metal
NASA Astrophysics Data System (ADS)
Chowdhury, Debanjan; Sachdev, Subir
2015-03-01
We analyze a candidate theory for the strange metal near optimal hole doping in the cuprate superconductors. The theory contains a quantum phase transition between metals with large and small Fermi surfaces of spinless fermions carrying the electromagnetic charge of the electron, but the transition does not directly involve any broken global symmetries. The two metals have emergent SU(2) and U(1) gauge fields respectively, and the transition is driven by the condensation of a real Higgs field, carrying a finite lattice momentum and an adjoint SU(2) gauge charge. This Higgs field measures the local antiferromagnetic correlations in a "rotating reference frame." We propose a global phase diagram around this Higgs transition, and describe its relationship to a variety of recent experiments on the cuprate superconductors.
Noncontractible hyperloops in gauge models with Higgs fields in the fundamental representation
NASA Astrophysics Data System (ADS)
Burzlaff, Jürgen
1984-11-01
We study finite-energy configurations in SO( N) gauge theories with Higgs fields in the fundamental representation. For all winding numbers, noncontractible hyperloops are constructed. The corresponding energy density is spherically symmetric, and the configuration with maximal energy on each hyperloop can be determined. Noncontractible hyperloops with an arbitrary winding number for SU(2) gauge theory are also given.
Gravitational waves from the first order phase transition of the Higgs field at high energy scales
NASA Astrophysics Data System (ADS)
Jinno, Ryusuke; Nakayama, Kazunori; Takimoto, Masahiro
2016-02-01
In a wide class of new physics models, there exist scalar fields that obtain vacuum expectation values of high energy scales. We study the possibility that the standard model Higgs field has experienced first order phase transition at the high energy scale due to the couplings with these scalar fields. We estimate the amount of gravitational waves produced by the phase transition, and discuss observational consequences.
Adjoint method and runaway electron avalanche
NASA Astrophysics Data System (ADS)
Liu, Chang; Brennan, Dylan P.; Boozer, Allen H.; Bhattacharjee, Amitava
2017-02-01
The adjoint method for the study of runaway electron dynamics in momentum space Liu et al (2016 Phys. Plasmas 23 010702) is rederived using the Green’s function method, for both the runaway probability function (RPF) and the expected loss time (ELT). The RPF and ELT obtained using the adjoint method are presented, both with and without the synchrotron radiation reaction force. The adjoint method is then applied to study the runaway electron avalanche. Both the critical electric field and the growth rate for the avalanche are calculated using this fast and novel approach.
Nonminimal Isotropic Cosmological Model with Yang-Mills and Higgs Fields
NASA Astrophysics Data System (ADS)
Balakin, Alexander B.; Dehnen, Heinz; Zayats, Alexei E.
We establish a nonminimal Einstein-Yang-Mills-Higgs model, which contains six coupling parameters. The first three parameters relate to the nonminimal coupling of a non-Abelian gauge field and a gravity field, the next two parameters describe the so-called derivative nonminimal coupling of a scalar multiplet with a gravity field, and the sixth parameter introduces the standard coupling of a scalar field with a Ricci scalar. The formulated six-parameter nonminimal Einstein-Yang-Mills-Higgs model is applied to cosmology. We show that there exists a unique exact cosmological solution of the de Sitter type for a special choice of the coupling parameters. The nonminimally extended Yang-Mills and Higgs equations are satisfied for arbitrary gauge and scalar fields, when the coupling parameters are specifically related to the curvature constant of the isotropic space-time. Based on this special exact solution, we discuss the problem of a hidden anisotropy of the Yang-Mills field, and give an explicit example, when the nonminimal coupling effectively screens the anisotropy induced by the Yang-Mills field and thus restores the isotropy of the model.
The behavior of the Higgs field in the new inflationary universe
NASA Technical Reports Server (NTRS)
Guth, Alan H.; Pi, So-Young
1986-01-01
Answers are provided to questions about the standard model of the new inflationary universe (NIU) which have raised concerns about the model's validity. A baby toy problem which consists of the study of a single particle moving in one dimension under the influence of a potential with the form of an upside-down harmonic oscillator is studied, showing that the quantum mechanical wave function at large times is accurately described by classical physics. Then, an exactly soluble toy model for the behavior of the Higgs field in the NIU is described which should provide a reasonable approximation to the behavior of the Higgs field in the NIU. The dynamics of the toy model is described, and calculative results are reviewed which, the authors claim, provide strong evidence that the basic features of the standard picture are correct.
Canonical Higgs fields from higher-dimensional gravity
NASA Astrophysics Data System (ADS)
Egeileh, Michel
2007-03-01
We consider the dimensional reduction of a gravitational field g in a multidimensional universe endowed with a simple action of a compact Lie group. It is known that when the group preserves g, this dimensional reduction leads in particular to scalar fields that correspond to an invariant metric on each orbit. We show that the action functionals of those fields (obtained from the reduction of Einstein's action) exhibit, in the hyperbolic case, polynomials of several variables having a degree less or equal to 6.
Gravitational wave production from the decay of the standard model Higgs field after inflation
NASA Astrophysics Data System (ADS)
Figueroa, Daniel G.; García-Bellido, Juan; Torrentí, Francisco
2016-05-01
During or towards the end of inflation, the Standard Model (SM) Higgs forms a condensate with a large amplitude. Following inflation, the condensate oscillates, decaying nonperturbatively into the rest of the SM species. The resulting out-of-equilibrium dynamics converts a fraction of the energy available into gravitational waves (GWs). We study this process using classical lattice simulations in an expanding box, following the energetically dominant electroweak gauge bosons W± and Z . We characterize the GW spectrum as a function of the running couplings, Higgs initial amplitude, and postinflationary expansion rate. As long as the SM is decoupled from the inflationary sector, the generation of this background is universally expected, independently of the nature of inflation. Our study demonstrates the efficiency of GW emission by gauge fields undergoing parametric resonance. The initial energy of the Higgs condensate represents, however, only a tiny fraction of the inflationary energy. Consequently, the resulting background is highly suppressed, with an amplitude h2ΩGW(o )≲1 0-29 today. The amplitude can be boosted to h2ΩGW(o )≲1 0-16 , if following inflation the universe undergoes a kination-domination stage; however, the background is shifted in this case to high frequencies fp≲1011 Hz . In all cases the signal is out of the range of current or planned GW detectors. This background will therefore remain, most likely, as a curiosity of the SM.
Self-dual configurations in Abelian Higgs models with k-generalized gauge field dynamics
NASA Astrophysics Data System (ADS)
Casana, R.; Cavalcante, A.; da Hora, E.
2016-12-01
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios where the gauge field possesses a k-generalized dynamic, i.e., the kinetic term of gauge field is a highly nonlinear function of F μν F μν . We have implemented our proposal by means of a k-generalized model displaying the spontaneous symmetry breaking phenomenon. We implement consistently the Bogomol'nyi-Prasad-Sommerfield formalism providing highly nonlinear self-dual equations whose solutions are electrically neutral possessing total energy proportional to the magnetic flux. Among the infinite set of possible configurations, we have found families of k-generalized models whose self-dual equations have a form mathematically similar to the ones arising in the Maxwell-Higgs or Chern-Simons-Higgs models. Furthermore, we have verified that our proposal also supports infinite twinlike models with | ϕ|4-potential or | ϕ|6-potential. With the aim to show explicitly that the BPS equations are able to provide well-behaved configurations, we have considered a test model in order to study axially symmetric vortices. By depending of the self-dual potential, we have shown that the k-generalized model is able to produce solutions that for long distances have a exponential decay (as Abrikosov-Nielsen-Olesen vortices) or have a power-law decay (characterizing delocalized vortices). In all cases, we observe that the generalization modifies the vortex core size, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux.
Inflation and reheating in the Starobinsky model with conformal HiggsField
NASA Astrophysics Data System (ADS)
Gorbunov, D. S.; Tokareva, A. A.
2013-12-01
This is a talk presented by A.A. Tokareva at Baikal summer school on physics of elementary particles and astrophysics 2012. We studied the reheating after the Starobinsky inflation and have found that the main process is the inflaton decay to SM gauge fields due to the conformal anomaly. The reheating temperature is low leading to the possibility to detect the gravity wave signal from inflation and evaporation of structures formed after inflation in DECIGO and BBO experiments. Also we give predictions for the parameters of scalar perturbation spectrum at the next-to-leading order of slow roll and obtain a bound on the Higgs mass.
Adjoint affine fusion and tadpoles
NASA Astrophysics Data System (ADS)
Urichuk, Andrew; Walton, Mark A.
2016-06-01
We study affine fusion with the adjoint representation. For simple Lie algebras, elementary and universal formulas determine the decomposition of a tensor product of an integrable highest-weight representation with the adjoint representation. Using the (refined) affine depth rule, we prove that equally striking results apply to adjoint affine fusion. For diagonal fusion, a coefficient equals the number of nonzero Dynkin labels of the relevant affine highest weight, minus 1. A nice lattice-polytope interpretation follows and allows the straightforward calculation of the genus-1 1-point adjoint Verlinde dimension, the adjoint affine fusion tadpole. Explicit formulas, (piecewise) polynomial in the level, are written for the adjoint tadpoles of all classical Lie algebras. We show that off-diagonal adjoint affine fusion is obtained from the corresponding tensor product by simply dropping non-dominant representations.
NASA Astrophysics Data System (ADS)
Kanemura, Shinya; Kikuchi, Mariko; Yagyu, Kei
2016-06-01
We calculate renormalized Higgs boson couplings with gauge bosons and fermions at the one-loop level in the model with an additional isospin singlet real scalar field. These coupling constants can deviate from the predictions in the standard model due to tree-level mixing effects and one-loop contributions of the extra neutral scalar boson. We investigate how they can be significant under the theoretical constraints from perturbative unitarity and vacuum stability and also the condition of avoiding the wrong vacuum. Furthermore, comparing with the predictions in the Type I two Higgs doublet model, we numerically demonstrate how the singlet extension model can be distinguished and identified by using precision measurements of the Higgs boson couplings at future collider experiments.
MCNP: Multigroup/adjoint capabilities
Wagner, J.C.; Redmond, E.L. II; Palmtag, S.P.; Hendricks, J.S.
1994-04-01
This report discusses various aspects related to the use and validity of the general purpose Monte Carlo code MCNP for multigroup/adjoint calculations. The increased desire to perform comparisons between Monte Carlo and deterministic codes, along with the ever-present desire to increase the efficiency of large MCNP calculations has produced a greater user demand for the multigroup/adjoint capabilities. To more fully utilize these capabilities, we review the applications of the Monte Carlo multigroup/adjoint method, describe how to generate multigroup cross sections for MCNP with the auxiliary CRSRD code, describe how to use the multigroup/adjoint capability in MCNP, and provide examples and results indicating the effectiveness and validity of the MCNP multigroup/adjoint treatment. This information should assist users in taking advantage of the MCNP multigroup/adjoint capabilities.
Z{sub 2} monopoles in SU(n) Yang-Mills-Higgs theories
Kneipp, Marco A. C.; Liebgott, Paulo J.
2010-02-15
Z{sub n} monopoles are important for the understanding of the Goddard-Nuyts-Olive duality when the scalar field is not in the adjoint representation. We analyze the Z{sub 2} monopole solutions in SU(n) Yang-Mills-Higgs theories spontaneously broken to Spin(n)/Z{sub 2} by a scalar in the nxn representation. We construct explicitly Z{sub 2} monopole asymptotic fields solutions for each of the weights of the defining representation of the dual algebra so(n){sup or.}
Adjoint sensitivity analysis of plasmonic structures using the FDTD method.
Zhang, Yu; Ahmed, Osman S; Bakr, Mohamed H
2014-05-15
We present an adjoint variable method for estimating the sensitivities of arbitrary responses with respect to the parameters of dispersive discontinuities in nanoplasmonic devices. Our theory is formulated in terms of the electric field components at the vicinity of perturbed discontinuities. The adjoint sensitivities are computed using at most one extra finite-difference time-domain (FDTD) simulation regardless of the number of parameters. Our approach is illustrated through the sensitivity analysis of an add-drop coupler consisting of a square ring resonator between two parallel waveguides. The computed adjoint sensitivities of the scattering parameters are compared with those obtained using the accurate but computationally expensive central finite difference approach.
NASA Astrophysics Data System (ADS)
Hashino, Katsuya; Kakizaki, Mitsuru; Kanemura, Shinya; Ko, Pyungwon; Matsui, Toshinori
2017-03-01
We calculate the spectrum of gravitational waves originated from strongly first order electroweak phase transition in the extended Higgs model with a real singlet scalar field. In order to calculate the bubble nucleation rate, we perform a two-field analysis and evaluate bounce solutions connecting the true and the false vacua using the one-loop effective potential at finite temperatures. Imposing the Sakharov condition of the departure from thermal equilibrium for baryogenesis, we survey allowed regions of parameters of the model. We then investigate the gravitational waves produced at electroweak bubble collisions in the early Universe, such as the sound wave, the bubble wall collision and the plasma turbulence. We find that the strength at the peak frequency can be large enough to be detected at future space-based gravitational interferometers such as eLISA, DECIGO and BBO. Predicted deviations in the various Higgs boson couplings are also evaluated at the zero temperature, and are shown to be large enough too. Therefore, in this model strongly first order electroweak phase transition can be tested by the combination of the precision study of various Higgs boson couplings at the LHC, the measurement of the triple Higgs boson coupling at future lepton colliders and the shape of the spectrum of gravitational wave detectable at future gravitational interferometers.
Dawson, S.; Haber, H.E.; Rindani, S.D.
1989-05-01
This is the summary report of the Higgs Boson Working Group. We discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K /yields/ /pi/H, /eta//prime/ /yields/ /eta/H,/Upsilon/ /yields/ H/gamma/ and e/sup +/e/sup /minus// /yields/ ZH are examined with particular attention paid to theoretical uncertainties in the calculations. We also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields. 33 refs., 6 figs., 1 tab.
Gradient-based optimum aerodynamic design using adjoint methods
NASA Astrophysics Data System (ADS)
Xie, Lei
2002-09-01
Continuous adjoint methods and optimal control theory are applied to a pressure-matching inverse design problem of quasi 1-D nozzle flows. Pontryagin's Minimum Principle is used to derive the adjoint system and the reduced gradient of the cost functional. The properties of adjoint variables at the sonic throat and the shock location are studied, revealing a log-arithmic singularity at the sonic throat and continuity at the shock location. A numerical method, based on the Steger-Warming flux-vector-splitting scheme, is proposed to solve the adjoint equations. This scheme can finely resolve the singularity at the sonic throat. A non-uniform grid, with points clustered near the throat region, can resolve it even better. The analytical solutions to the adjoint equations are also constructed via Green's function approach for the purpose of comparing the numerical results. The pressure-matching inverse design is then conducted for a nozzle parameterized by a single geometric parameter. In the second part, the adjoint methods are applied to the problem of minimizing drag coefficient, at fixed lift coefficient, for 2-D transonic airfoil flows. Reduced gradients of several functionals are derived through application of a Lagrange Multiplier Theorem. The adjoint system is carefully studied including the adjoint characteristic boundary conditions at the far-field boundary. A super-reduced design formulation is also explored by treating the angle of attack as an additional state; super-reduced gradients can be constructed either by solving adjoint equations with non-local boundary conditions or by a direct Lagrange multiplier method. In this way, the constrained optimization reduces to an unconstrained design problem. Numerical methods based on Jameson's finite volume scheme are employed to solve the adjoint equations. The same grid system generated from an efficient hyperbolic grid generator are adopted in both the Euler flow solver and the adjoint solver. Several
Optimal ignition placement using nonlinear adjoint looping
NASA Astrophysics Data System (ADS)
Qadri, Ubaid; Schmid, Peter; Magri, Luca; Ihme, Matthias
2016-11-01
Spark ignition of a turbulent mixture of fuel and oxidizer is a highly sensitive process. Traditionally, a large number of parametric studies are used to determine the effects of different factors on ignition and this can be quite tedious. In contrast, we treat ignition as an initial value problem and seek to find the initial condition that maximizes a given cost function. We use direct numerical simulation of the low Mach number equations with finite rate one-step chemistry, and of the corresponding adjoint equations, to study an axisymmetric jet diffusion flame. We find the L - 2 norm of the temperature field integrated over a short time to be a suitable cost function. We find that the adjoint fields localize around the flame front, identifying the most sensitive region of the flow. The adjoint fields provide gradient information that we use as part of an optimization loop to converge to a local optimal ignition location. We find that the optimal locations correspond with the stoichiometric surface downstream of the jet inlet plane. The methods and results of this study can be easily applied to more complex flow geometries.
NASA Astrophysics Data System (ADS)
Bozdag, Ebru; Lefebvre, Matthieu; Lei, Wenjie; Peter, Daniel; Smith, James; Komatitsch, Dimitri; Tromp, Jeroen
2015-04-01
We will present our initial results of global adjoint tomography based on 3D seismic wave simulations which is one of the most challenging examples in seismology in terms of intense computational requirements and vast amount of high-quality seismic data that can potentially be assimilated in inversions. Using a spectral-element method, we incorporate full 3D wave propagation in seismic tomography by running synthetic seismograms and adjoint simulations to compute exact sensitivity kernels in realistic 3D background models. We run our global simulations on the Oak Ridge National Laboratory's Cray XK7 "Titan" system taking advantage of the GPU version of the SPECFEM3D_GLOBE package. We have started iterations with initially selected 253 earthquakes within the magnitude range of 5.5 < Mw < 7.0 and numerical simulations having resolution down to ~27 s to invert for a transversely isotropic crust and mantle model using a non-linear conjugate gradient algorithm. The measurements are currently based on frequency-dependent traveltime misfits. We use both minor- and major-arc body and surface waves by running 200 min simulations where inversions are performed with more than 2.6 million measurements. Our initial results after 12 iterations already indicate several prominent features such as enhanced slab (e.g., Hellenic, Japan, Bismarck, Sandwich), plume/hotspot (e.g., the Pacific superplume, Caroline, Yellowstone, Hawaii) images, etc. To improve the resolution and ray coverage, particularly in the lower mantle, our aim is to increase the resolution of numerical simulations first going down to ~17 s and then to ~9 s to incorporate high-frequency body waves in inversions. While keeping track of the progress and illumination of features in our models with a limited data set, we work towards to assimilate all available data in inversions from all seismic networks and earthquakes in the global CMT catalogue.
Unsteady adjoint of a gas turbine inlet guide vane
NASA Astrophysics Data System (ADS)
Talnikar, Chaitanya; Wang, Qiqi
2015-11-01
Unsteady fluid flow simulations like large eddy simulation have been shown to be crucial in accurately predicting heat transfer in turbomachinery applications like transonic flow over an inlet guide vane. To compute sensitivities of aerothermal objectives for a vane with respect to design parameters an unsteady adjoint is required. In this talk we present unsteady adjoint solutions for a vane from VKI using pressure loss and heat transfer over the vane surface as the objectives. The boundary layer on the suction side near the trailing edge of the vane is turbulent and this poses a challenge for an adjoint solver. The chaotic dynamics cause the adjoint solution to diverge exponentially to infinity from that region when simulated backwards in time. The prospect of adding artificial viscosity to the adjoint equations to dampen the adjoint fields is investigated. Results for the vane from simulations performed on the Titan supercomputer will be shown and the effect of the additional viscosity on the accuracy of the sensitivities will be discussed.
The one and a half monopoles solution of the SU(2) Yang–Mills–Higgs field theory
Teh, Rosy Ng, Ban-Loong; Wong, Khai-Ming
2014-04-15
Recently we have reported on the existence of finite energy SU(2) Yang–Mills–Higgs particle of one-half topological charge. In this paper, we show that this one-half monopole can co-exist with a ’t Hooft–Polyakov monopole. The magnetic charge of the one-half monopole is of opposite sign to the magnetic charge of the ’t Hooft–Polyakov monopole. However the net magnetic charge of the configuration is zero due to the presence of a semi-infinite Dirac string along the positive z-axis that carries the other half of the magnetic monopole charge. The solution possesses gauge potentials that are singular along the z-axis, elsewhere they are regular. The total energy is found to increase with the strength of the Higgs field self-coupling constant λ. However the dipole separation and the magnetic dipole moment decrease with λ. This solution is non-BPS even in the BPS limit when the Higgs self-coupling constant vanishes. -- Highlights: •This one-half monopole can co-exist with a ’t Hooft–Polyakov monopole. •The magnetic charge of the one-half monopole and one monopole is of opposite sign. •This solution is non-BPS. •The net magnetic charge of the configuration is zero. •This solution upon Cho decomposition is only singular along the negative z-axis.
Higgs couplings in noncommutative Standard Model
NASA Astrophysics Data System (ADS)
Batebi, S.; Haghighat, M.; Tizchang, S.; Akafzade, H.
2015-06-01
We consider the Higgs and Yukawa parts of the Noncommutative Standard Model (NCSM). We explore the NC-action to give all Feynman rules for couplings of the Higgs boson to electroweak gauge fields and fermions.
General composite Higgs models
NASA Astrophysics Data System (ADS)
Marzocca, David; Serone, Marco; Shu, Jing
2012-08-01
We construct a general class of pseudo-Goldstone composite Higgs models, within the minimal SO(5)/SO(4) coset structure, that are not necessarily of moose-type. We characterize the main properties these models should have in order to give rise to a Higgs mass around 125 GeV. We assume the existence of relatively light and weakly coupled spin 1 and 1/2 resonances. In absence of a symmetry principle, we introduce the Minimal Higgs Potential (MHP) hypothesis: the Higgs potential is assumed to be one-loop dominated by the SM fields and the above resonances, with a contribution that is made calculable by imposing suitable generalizations of the first and second Weinberg sum rules. We show that a 125 GeV Higgs requires light, often sub-TeV, fermion resonances. Their presence can also be important for the models to successfully pass the electroweak precision tests. Interestingly enough, the latter can also be passed by models with a heavy Higgs around 320 GeV. The composite Higgs models of the moose-type considered in the literature can be seen as particular limits of our class of models.
NASA Astrophysics Data System (ADS)
Maltoni, Fabio; Vryonidou, Eleni; Zhang, Cen
2016-10-01
We present the results of the computation of the next-to-leading order QCD corrections to the production cross section of a Higgs boson in association with a top-antitop pair at the LHC, including the three relevant dimension-six operators ( O tφ , O φG , O tG ) of the standard model effective field theory. These operators also contribute to the production of Higgs bosons in loop-induced processes at the LHC, such as inclusive Higgs, Hj and HH production, and modify the Higgs decay branching ratios for which we also provide predictions. We perform a detailed study of the cross sections and their uncertainties at the total as well as differential level and of the structure of the effective field theory at NLO including renormalisation group effects. Finally, we show how the combination of information coming from measurements of these production processes will allow to constrain the three operators at the current and future LHC runs. Our results lead to a significant improvement of the accuracy and precision of the deviations expected from higher-dimensional operators in the SM in both the top-quark and the Higgs-boson sectors and provide a necessary ingredient for performing a global EFT fit to the LHC data at NLO accuracy.
Maltoni, Fabio; Vryonidou, Eleni; Zhang, Cen
2016-10-24
We present the results of the computation of the next-to-leading order QCD corrections to the production cross section of a Higgs boson in association with a top-antitop pair at the LHC, including the three relevant dimension-six operators (O_{tφ}, O_{φG}, O_{tG}) of the standard model effective field theory. These operators also contribute to the production of Higgs bosons in loop-induced processes at the LHC, such as inclusive Higgs, Hj and HH production, and modify the Higgs decay branching ratios for which we also provide predictions. We perform a detailed study of the cross sections and their uncertainties at the total as well as differential level and of the structure of the effective field theory at NLO including renormalisation group effects. Finally, we show how the combination of information coming from measurements of these production processes will allow to constrain the three operators at the current and future LHC runs. Finally, our results lead to a significant improvement of the accuracy and precision of the deviations expected from higher-dimensional operators in the SM in both the top-quark and the Higgs-boson sectors and provide a necessary ingredient for performing a global EFT fit to the LHC data at NLO accuracy.
Maltoni, Fabio; Vryonidou, Eleni; Zhang, Cen
2016-10-24
We present the results of the computation of the next-to-leading order QCD corrections to the production cross section of a Higgs boson in association with a top-antitop pair at the LHC, including the three relevant dimension-six operators (Otφ, OφG, OtG) of the standard model effective field theory. These operators also contribute to the production of Higgs bosons in loop-induced processes at the LHC, such as inclusive Higgs, Hj and HH production, and modify the Higgs decay branching ratios for which we also provide predictions. We perform a detailed study of the cross sections and their uncertainties at the total asmore » well as differential level and of the structure of the effective field theory at NLO including renormalisation group effects. Finally, we show how the combination of information coming from measurements of these production processes will allow to constrain the three operators at the current and future LHC runs. Finally, our results lead to a significant improvement of the accuracy and precision of the deviations expected from higher-dimensional operators in the SM in both the top-quark and the Higgs-boson sectors and provide a necessary ingredient for performing a global EFT fit to the LHC data at NLO accuracy.« less
Adjoint-based approach to Enhancing Mixing in Rayleigh-Taylor Turbulence
NASA Astrophysics Data System (ADS)
Kord, Ali; Capecelatro, Jesse
2016-11-01
A recently developed adjoint method for multi-component compressible flow is used to measure sensitivity of the mixing rate to initial perturbations in Rayleigh-Taylor (RT) turbulence. Direct numerical simulations (DNS) of RT instabilities are performed at moderate Reynolds numbers. The DNS are used to provide an initial prediction, and the corresponding space-time discrete-exact adjoint provides a sensitivity gradient for a specific quantity of interest (QoI). In this work, a QoI is defined based on the time-integrated scalar field to quantify the mixing rate. Therefore, the adjoint solution is used to measure sensitivity of this QoI to a set of initial perturbations, and inform a gradient-based line search to optimize mixing. We first demonstrate the adjoint approach in the linear regime and compare the optimized initial conditions to the expected values from linear stability analysis. The adjoint method is then used in the high Reynolds number limit where theory is no longer valid. Finally, chaos is known to contaminate the accuracy of the adjoint gradient in turbulent flows when integrated over long time horizons. We assess the influence of chaos on the accuracy of the adjoint gradient to guide the work of future studies on adjoint-based sensitivity of turbulent mixing. PhD Student, Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI.
Study on adjoint-based optimization method for multi-stage turbomachinery
NASA Astrophysics Data System (ADS)
Li, Weiwei; Tian, Yong; Yi, Weilin; Ji, Lucheng; Shao, Weiwei; Xiao, Yunhan
2011-10-01
Adjoint-based optimization method is a hotspot in turbomachinery. First, this paper presents principles of adjoint method from Lagrange multiplier viewpoint. Second, combining a continuous route with thin layer RANS equations, we formulate adjoint equations and anti-physical boundary conditions. Due to the multi-stage environment in turbomachinery, an adjoint interrow mixing method is introduced. Numerical techniques of solving flow equations and adjoint equations are almost the same, and once they are converged respectively, the gradients of an objective function to design variables can be calculated using complex method efficiently. Third, integrating a shape perturbation parameterization and a simple steepest descent method, a frame of adjoint-based aerodynamic shape optimization for multi-stage turbomachinery is constructed. At last, an inverse design of an annular cascade is employed to validate the above approach, and adjoint field of an Aachen 1.5 stage turbine demonstrates the conservation and areflexia of the adjoint interrow mixing method. Then a direct redesign of a 1+1 counter-rotating turbine aiming to increase efficiency and apply constraints to mass flow rate and pressure ratio is taken.
NASA Astrophysics Data System (ADS)
Passarino, Giampiero
2014-05-01
Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape ( and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis.
MS S4.03.002 - Adjoint-Based Design for Configuration Shaping
NASA Technical Reports Server (NTRS)
Nemec, Marian; Aftosmis, Michael J.
2009-01-01
This slide presentation discusses a method of inverse design for low sonic boom using adjoint-based gradient computations. It outlines a method for shaping a configuration in order to match a prescribed near-field signature.
Muon g -2 in gauge mediated supersymmetry breaking models with adjoint messengers
NASA Astrophysics Data System (ADS)
Gogoladze, Ilia; Ün, Cem Salih
2017-02-01
We explored the sparticle mass spectrum in light of the muon g -2 anomaly and the little hierarchy problem in a class of the gauge mediated supersymmetry breaking model. Here, the messenger fields transform in the adjoint representation of the Standard Model gauge symmetry. To avoid unacceptably light right-handed slepton masses, the Standard Model is supplemented by the additional U (1 )B-L gauge symmetry. A nonzero U (1 )B-L D term makes the right-handed slepton masses compatible with the current experimental bounds. We show that in the framework of Λ3<0 and μ <0 the muon g -2 anomaly and the observed 125 GeV Higgs boson mass can be simultaneously accommodated. The slepton masses in this case are predicted to lie in the few hundred GeV range, which can be tested at the LHC. Despite the heavy colored sparticle spectrum, the little hierarchy problem in this model can be ameliorated, and the electroweak fine-tuning parameter can be as low as 10 or so.
Higgs masses and stability in the standard and the two Higgs doublet models
Juarez W, S. R.; Morales C, D.; Kielanowski, P.
2010-07-29
Within the framework of the standard model (SM) of elementary particles and the two Higgs doublet extension to this model (2DHM), we obtained analytical and numerical solutions for the gauge couplings, the vacuum expectation values (VEV) of the Higgs fields, the quark Yukawa couplings and quark masses, the quartic Higgs couplings, and the running Higgs masses, considering the renormalization group equations. The bounds on the SM Higgs running mass have been fixed, and the region of validity of the SM was determined through it, at the one and two loop approximations, using the triviality and stability conditions for the Higgs quartic coupling {lambda}{sub H}.
Numerical Computation of Sensitivities and the Adjoint Approach
NASA Technical Reports Server (NTRS)
Lewis, Robert Michael
1997-01-01
We discuss the numerical computation of sensitivities via the adjoint approach in optimization problems governed by differential equations. We focus on the adjoint problem in its weak form. We show how one can avoid some of the problems with the adjoint approach, such as deriving suitable boundary conditions for the adjoint equation. We discuss the convergence of numerical approximations of the costate computed via the weak form of the adjoint problem and show the significance for the discrete adjoint problem.
Bevis, Neil; Hindmarsh, Mark; Kunz, Martin; Urrestilla, Jon
2007-03-15
We present the first field-theoretic calculations of the contribution made by cosmic strings to the temperature power spectrum of the cosmic microwave background (CMB). Unlike previous work, in which strings were modeled as idealized one-dimensional objects, we evolve the simplest example of an underlying field theory containing local U(1) strings, the Abelian Higgs model. Limitations imposed by finite computational volumes are overcome using the scaling property of string networks and a further extrapolation related to the lessening of the string width in comoving coordinates. The strings and their decay products, which are automatically included in the field theory approach, source metric perturbations via their energy-momentum tensor, the unequal-time correlation functions of which are used as input into the CMB calculation phase. These calculations involve the use of a modified version of CMBEASY, with results provided over the full range of relevant scales. We find that the string tension {mu} required to normalize to the WMAP 3-year data at multipole l=10 is G{mu}=[2.04{+-}0.06(stat.){+-}0.12(sys.)]x10{sup -6}, where we have quoted statistical and systematic errors separately, and G is Newton's constant. This is a factor 2-3 higher than values in current circulation.
DAI,YANG; BORISOV,ALEXEY B.; BOYER,KEITH; RHODES,CHARLES K.
2000-08-11
The construction of inverse states in a finite field F{sub P{sub {alpha}}} enables the organization of the mass scale with fundamental octets in an eight-dimensional index space that identifies particle states with residue class designations. Conformance with both CPT invariance and the concept of supersymmetry follows as a direct consequence of this formulation. Based on two parameters (P{sub {alpha}} and g{sub {alpha}}) that are anchored on a concordance of physical data, this treatment leads to (1) a prospective mass for the muon neutrino of {approximately}27.68 meV, (2) a value of the unified strong-electroweak coupling constant {alpha}* = (34.26){sup {minus}1} that is physically defined by the ratio of the electron neutrino and muon neutrino masses, and (3) a see-saw congruence connecting the Higgs, the electron neutrino, and the muon neutrino masses. Specific evaluation of the masses of the corresponding supersymmetric Higgs pair reveals that both particles are superheavy (> 10{sup 18}GeV). No renormalization of the Higgs masses is introduced, since the calculational procedure yielding their magnitudes is intrinsically divergence-free. Further, the Higgs fulfills its conjectured role through the see-saw relation as the particle defining the origin of all particle masses, since the electron and muon neutrino systems, together with their supersymmetric partners, are the generators of the mass scale and establish the corresponding index space. Finally, since the computation of the Higgs masses is entirely determined by the modulus of the field P{sub {alpha}}, which is fully defined by the large-scale parameters of the universe through the value of the universal gravitational constant G and the requirement for perfect flatness ({Omega} = 1.0), the see-saw congruence fuses the concepts of mass and space and creates a new unified archetype.
Adjoint sensitivity study on idealized explosive cyclogenesis
NASA Astrophysics Data System (ADS)
Chu, Kekuan; Zhang, Yi
2016-06-01
The adjoint sensitivity related to explosive cyclogenesis in a conditionally unstable atmosphere is investigated in this study. The PSU/NCAR limited-area, nonhydrostatic primitive equation numerical model MM5 and its adjoint system are employed for numerical simulation and adjoint computation, respectively. To ensure the explosive development of a baroclinic wave, the forecast model is initialized with an idealized condition including an idealized two-dimensional baroclinic jet with a balanced three-dimensional moderate-amplitude disturbance, derived from a potential vorticity inversion technique. Firstly, the validity period of the tangent linear model for this idealized baroclinic wave case is discussed, considering different initial moisture distributions and a dry condition. Secondly, the 48-h forecast surface pressure center and the vertical component of the relative vorticity of the cyclone are selected as the response functions for adjoint computation in a dry and moist environment, respectively. The preliminary results show that the validity of the tangent linear assumption for this idealized baroclinic wave case can extend to 48 h with intense moist convection, and the validity period can last even longer in the dry adjoint integration. Adjoint sensitivity analysis indicates that the rapid development of the idealized baroclinic wave is sensitive to the initial wind and temperature perturbations around the steering level in the upstream. Moreover, the moist adjoint sensitivity can capture a secondary high sensitivity center in the upper troposphere, which cannot be depicted in the dry adjoint run.
Adjoint Error Estimation for Linear Advection
Connors, J M; Banks, J W; Hittinger, J A; Woodward, C S
2011-03-30
An a posteriori error formula is described when a statistical measurement of the solution to a hyperbolic conservation law in 1D is estimated by finite volume approximations. This is accomplished using adjoint error estimation. In contrast to previously studied methods, the adjoint problem is divorced from the finite volume method used to approximate the forward solution variables. An exact error formula and computable error estimate are derived based on an abstractly defined approximation of the adjoint solution. This framework allows the error to be computed to an arbitrary accuracy given a sufficiently well resolved approximation of the adjoint solution. The accuracy of the computable error estimate provably satisfies an a priori error bound for sufficiently smooth solutions of the forward and adjoint problems. The theory does not currently account for discontinuities. Computational examples are provided that show support of the theory for smooth solutions. The application to problems with discontinuities is also investigated computationally.
Accurate adjoint design sensitivities for nano metal optics.
Hansen, Paul; Hesselink, Lambertus
2015-09-07
We present a method for obtaining accurate numerical design sensitivities for metal-optical nanostructures. Adjoint design sensitivity analysis, long used in fluid mechanics and mechanical engineering for both optimization and structural analysis, is beginning to be used for nano-optics design, but it fails for sharp-cornered metal structures because the numerical error in electromagnetic simulations of metal structures is highest at sharp corners. These locations feature strong field enhancement and contribute strongly to design sensitivities. By using high-accuracy FEM calculations and rounding sharp features to a finite radius of curvature we obtain highly-accurate design sensitivities for 3D metal devices. To provide a bridge to the existing literature on adjoint methods in other fields, we derive the sensitivity equations for Maxwell's equations in the PDE framework widely used in fluid mechanics.
Sakurai Prize: Extended Higgs Sectors--phenomenology and future prospects
NASA Astrophysics Data System (ADS)
Gunion, John
2017-01-01
The discovery of a spin-0 state at 125 GeV with properties close to those predicted for the single Higgs boson of the Standard Model does not preclude the existence of additional Higgs bosons. In this talk, models with extended Higgs sectors are reviewed, including two-Higgs-doublet models with and without an extra singlet Higgs field and supersymmetric models. Special emphasis is given to the limit in which the couplings and properties of one of the Higgs bosons of the extended Higgs sector are very close to those predicted for the single Standard Model Higgs boson while the other Higgs bosons are relatively light, perhaps even having masses close to or below the SM-like 125 GeV state. Constraints on this type of scenario given existing data are summarized and prospects for observing these non-SM-like Higgs bosons are discussed. Supported by the Department of Energy.
On the role of self-adjointness in the continuum formulation of topological quantum phases
NASA Astrophysics Data System (ADS)
Tanhayi Ahari, Mostafa; Ortiz, Gerardo; Seradjeh, Babak
2016-11-01
Topological quantum phases of matter are characterized by an intimate relationship between the Hamiltonian dynamics away from the edges and the appearance of bound states localized at the edges of the system. Elucidating this correspondence in the continuum formulation of topological phases, even in the simplest case of a one-dimensional system, touches upon fundamental concepts and methods in quantum mechanics that are not commonly discussed in textbooks, in particular the self-adjoint extensions of a Hermitian operator. We show how such topological bound states can be derived in a prototypical one-dimensional system. Along the way, we provide a pedagogical exposition of the self-adjoint extension method as well as the role of symmetries in correctly formulating the continuum, field-theory description of topological matter with boundaries. Moreover, we show that self-adjoint extensions can be characterized generally in terms of a conserved local current associated with the self-adjoint operator.
NASA Astrophysics Data System (ADS)
Bellazzini, Brando; Csáki, Csaba; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John
2016-10-01
The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However, light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper, we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in anti-de Sitter space. For both of these models, we consider the processes g g →Z Z and g g →h h , which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.
Electroweak Baryogenesis and Higgs Properties
Cohen, Timothy; Morrissey, David E.; Pierce, Aaron; /Michigan U., MCTP
2012-03-13
We explore the connection between the strength of the electroweak phase transition and the properties of the Higgs boson. Our interest is in regions of parameter space that can realize electroweak baryogenesis. We do so in a simplified framework in which a single Higgs field couples to new scalar fields charged under SU(3){sub c} by way of the Higgs portal. Such new scalars can make the electroweak phase transition more strongly first-order, while contributing to the effective Higgs boson couplings to gluons and photons through loop effects. For Higgs boson masses in the range 115 {approx}< m{sub h} {approx}< 130 GeV, whenever the phase transition becomes strong enough for successful electroweak baryogenesis, we find that Higgs boson properties are modified by an amount observable by the LHC. We also discuss the baryogenesis window of the minimal supersymmetric standard model (MSSM), which appears to be under tension. Furthermore, we argue that the discovery of a Higgs boson with standard model-like couplings to gluons and photons will rule out electroweak baryogenesis in the MSSM.
Adjoint Fokker-Planck equation and runaway electron dynamics
Liu, Chang; Brennan, Dylan P.; Bhattacharjee, Amitava; Boozer, Allen H.
2016-01-15
The adjoint Fokker-Planck equation method is applied to study the runaway probability function and the expected slowing-down time for highly relativistic runaway electrons, including the loss of energy due to synchrotron radiation. In direct correspondence to Monte Carlo simulation methods, the runaway probability function has a smooth transition across the runaway separatrix, which can be attributed to effect of the pitch angle scattering term in the kinetic equation. However, for the same numerical accuracy, the adjoint method is more efficient than the Monte Carlo method. The expected slowing-down time gives a novel method to estimate the runaway current decay time in experiments. A new result from this work is that the decay rate of high energy electrons is very slow when E is close to the critical electric field. This effect contributes further to a hysteresis previously found in the runaway electron population.
Adjoint Fokker-Planck equation and runaway electron dynamics
NASA Astrophysics Data System (ADS)
Liu, Chang; Brennan, Dylan P.; Bhattacharjee, Amitava; Boozer, Allen H.
2016-01-01
The adjoint Fokker-Planck equation method is applied to study the runaway probability function and the expected slowing-down time for highly relativistic runaway electrons, including the loss of energy due to synchrotron radiation. In direct correspondence to Monte Carlo simulation methods, the runaway probability function has a smooth transition across the runaway separatrix, which can be attributed to effect of the pitch angle scattering term in the kinetic equation. However, for the same numerical accuracy, the adjoint method is more efficient than the Monte Carlo method. The expected slowing-down time gives a novel method to estimate the runaway current decay time in experiments. A new result from this work is that the decay rate of high energy electrons is very slow when E is close to the critical electric field. This effect contributes further to a hysteresis previously found in the runaway electron population.
Peters, Krisztian
2009-11-01
We present the status and prospects of Higgs searches at the Tevatron and the LHC. Results from the Tevatron are using up to 5 fb{sup -} of data collected with the CDF and D0 detectors. The major contributing processes include associated production (WH {yields} l{nu}bb, ZH {yields} {nu}{nu}bb, ZH {yields} llbb) and gluon fusion (gg {yields} H {yields} WW{sup (*)}). Improvements across the full mass range resulting from the larger data sets, improved analyses techniques and increased signal acceptance are discussed. Recent results exclude the SM Higgs boson in a mass range of 160 < m{sub H} < 170 GeV. Searches for the neutral MSSM Higgs boson in the region 90 < m{sub A} < 200 GeV exclude tan {beta} values down to 30 for several benchmark scenarios.
Higgs couplings and new signals from Flavon-Higgs mixing effects within multi-scalar models
NASA Astrophysics Data System (ADS)
Diaz-Cruz, J. Lorenzo; Saldaña-Salazar, Ulises J.
2016-12-01
Testing the properties of the Higgs particle discovered at the LHC and searching for new physics signals, are some of the most important tasks of Particle Physics today. Current measurements of the Higgs couplings to fermions and gauge bosons, seem consistent with the Standard Model, and when taken as a function of the particle mass, should lay on a single line. However, in models with an extended Higgs sector the diagonal Higgs couplings to up-quarks, down-quarks and charged leptons, could lay on different lines, while non-diagonal flavor-violating Higgs couplings could appear too. We describe these possibilities within the context of multi-Higgs doublet models that employ the Froggatt-Nielsen (FN) mechanism to generate the Yukawa hierarchies. Furthermore, one of the doublets can be chosen to be of the inert type, which provides a viable dark matter candidate. The mixing of the Higgs doublets with the flavon field, can provide plenty of interesting signals, including: i) small corrections to the couplings of the SM-like Higgs, ii) exotic signals from the flavon fields, iii) new signatures from the heavy Higgs bosons. These aspects are studied within a specific model with 3 + 1 Higgs doublets and a singlet FN field. Constraints on the model are derived from the study of K and D mixing and the Higgs search at the LHC. For last, the implications from the latter aforementioned constraints to the FCNC top decay t → ch are presented too.
Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector
de Florian, D.
2016-10-25
This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions of Higgs boson production cross sections and decay branching ratios, parton distribution functions, and off-shell Higgs boson production and interference effects. The second part discusses the recent progress in Higgs effective field theory predictions, followed by the third part on pseudo-observables, simplified template cross section and fiducial cross section measurements, which give the baseline framework for Higgs boson property measurements. The fourth part deals with the beyond the Standard Model predictions of various benchmark scenarios of Minimal Supersymmetric Standard Model, extended scalar sector, Next-to-Minimal Supersymmetric Standard Model and exotic Higgs boson decays. This report follows three previous working-group reports: Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002), Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002), and Handbook of LHC Higgs Cross Sections: 3. Higgs properties (CERN-2013-004). The current report serves as the baseline reference for Higgs physics in LHC Run 2 and beyond.
Bardeen, William A.; /Fermilab
2008-05-01
I discuss the Standard Model of Elementary Particle Physics and potential for discoveries of the physics responsible for electroweak symmetry breaking. I review the ideas leading to development of the Brout-Englert-Higgs mechanism that now forms the basis for the conventional Standard Model. I discuss various issues that challenge application of the Standard Model to the known physics of elementary particles. I examine alternatives to the Standard Model that address these issues and may lead to new discoveries at the LHC that go Beyond Higgs.
Important literature on the use of adjoint, variational methods and the Kalman filter in meteorology
NASA Astrophysics Data System (ADS)
Courtier, Philippe; Derber, John; Errico, Ron; Louis, Jean-Francois; Vukićević, Tomislava
1993-10-01
The use of adjoint equations is proving to be invaluable in many areas of meteorological research. Unlike a forecast model which describes the evolution of meteorological fields forward in time, the adjoint equations describe the evolution of sensitivity (to initial, boundary and parametric conditions) backward in time. Essentially, by utilizing this sensitivity information, many types of problems can be solved more efficiently than in the past, including variational data assimilation, parameter fitting, optimal instability and sensitivity analysis in general. For this reason, the adjoints of various models and their applications have been appearing more and more frequently in meteorological research. This paper is a bibliography in chronological order of published works in meteorology dealing with adjoints which have appeared prior to this issue of Tellus. Also included are meteorological works regarding variational methods (even without adjoints) and Kalman filtering in data assimilation, plus some references outside meteorology. These additional works are included here because the main thrust for adjoint application within meteorology is currently concentrated in the development of next-generation data assimilation systems.
Graceful exit from Higgs G inflation
NASA Astrophysics Data System (ADS)
Kamada, Kohei; Kobayashi, Tsutomu; Kunimitsu, Taro; Yamaguchi, Masahide; Yokoyama, Jun'ichi
2013-12-01
Higgs G inflation is a Higgs inflation model with a generalized Galileon term added to the standard model Higgs field, which realizes inflation compatible with observations. Recently, it was claimed that the generalized Galileon term induces instabilities during the oscillation phase and that the simplest Higgs G-inflation model inevitably suffers from this problem. In this paper, we extend the original Higgs G-inflation Lagrangian to a more general form, namely introducing a higher-order kinetic term and generalizing the form of the Galileon term, so that the Higgs field can oscillate after inflation without encountering instabilities. Moreover, it accommodates a large region of the ns-r plane, most of which is consistent with current observations, leading us to expect the detection of B-mode polarization in the cosmic microwave background in the near future.
On the adjoint operator in photoacoustic tomography
NASA Astrophysics Data System (ADS)
Arridge, Simon R.; Betcke, Marta M.; Cox, Ben T.; Lucka, Felix; Treeby, Brad E.
2016-11-01
Photoacoustic tomography (PAT) is an emerging biomedical imaging from coupled physics technique, in which the image contrast is due to optical absorption, but the information is carried to the surface of the tissue as ultrasound pulses. Many algorithms and formulae for PAT image reconstruction have been proposed for the case when a complete data set is available. In many practical imaging scenarios, however, it is not possible to obtain the full data, or the data may be sub-sampled for faster data acquisition. In such cases, image reconstruction algorithms that can incorporate prior knowledge to ameliorate the loss of data are required. Hence, recently there has been an increased interest in using variational image reconstruction. A crucial ingredient for the application of these techniques is the adjoint of the PAT forward operator, which is described in this article from physical, theoretical and numerical perspectives. First, a simple mathematical derivation of the adjoint of the PAT forward operator in the continuous framework is presented. Then, an efficient numerical implementation of the adjoint using a k-space time domain wave propagation model is described and illustrated in the context of variational PAT image reconstruction, on both 2D and 3D examples including inhomogeneous sound speed. The principal advantage of this analytical adjoint over an algebraic adjoint (obtained by taking the direct adjoint of the particular numerical forward scheme used) is that it can be implemented using currently available fast wave propagation solvers.
Adjoint modeling for atmospheric pollution process sensitivity at regional scale
NASA Astrophysics Data System (ADS)
Menut, Laurent
2003-09-01
During the summer 1998, a strong pollution event was documented over Paris as part of the Etude et Simulation de la Qualité de l'air en Ile-de-France (ESQUIF) project (second intensive observation period (IOP2)). From 7 to 9 August 1998 the pollution event changes from a well-marked ozone plume issued from Paris to a more general pollution over the whole Ile-de-France region. Using a three-dimensional chemistry-transport model and its adjoint part, the sensitivity of ozone, Ox, and NOx peaks to model parameters is investigated. For two locations, Paris and a suburban site, the influence of both meteorological and chemical model parameters on the simulated field concentrations is hourly quantified for each day. Processes leading to a urban polluted event are compared. It is shown that the pollutant concentrations are mainly driven by traffic and solvent surface emissions and meteorological parameters such as temperature. Since the adjoint approach is limited to infinitesimal model perturbation, some scenario simulations are carried out to evaluate the linearity of the impact of the most sensitive parameters within the uncertainty range. It is shown that the sensitivities determined from the adjoint approach can be extrapolated until their uncertainty ranges except for the wind speed.
Continuous adjoint sensitivity analysis for aerodynamic and acoustic optimization
NASA Astrophysics Data System (ADS)
Ghayour, Kaveh
1999-11-01
A gradient-based shape optimization methodology based on continuous adjoint sensitivities has been developed for two-dimensional steady Euler equations on unstructured meshes and the unsteady transonic small disturbance equation. The continuous adjoint sensitivities of the Helmholtz equation for acoustic applications have also been derived and discussed. The highlights of the developments for the steady two-dimensional Euler equations are the generalization of the airfoil surface boundary condition of the adjoint system to allow a proper closure of the Lagrangian functional associated with a general cost functional and the results for an inverse problem with density as the prescribed target. Furthermore, it has been demonstrated that a transformation to the natural coordinate system, in conjunction with the reduction of the governing state equations to the control surface, results in sensitivity integrals that are only a function of the tangential derivatives of the state variables. This approach alleviates the need for directional derivative computations with components along the normal to the control surface, which can render erroneous results. With regard to the unsteady transonic small disturbance equation (UTSD), the continuous adjoint methodology has been successfully extended to unsteady flows. It has been demonstrated that for periodic airfoil oscillations leading to limit-cycle behavior, the Lagrangian functional can be only closed if the time interval of interest spans one or more periods of the flow oscillations after the limit-cycle has been attained. The steady state and limit-cycle sensitivities are then validated by comparing with the brute-force derivatives. The importance of accounting for the flow circulation sensitivity, appearing in the form of a Dirac delta in the wall boundary condition at the trailing edge, has been stressed and demonstrated. Remarkably, the cost of an unsteady adjoint solution is about 0.2 times that of a UTSD solution
Baryogenesis via leptogenesis in adjoint SU(5)
Blanchet, Steve; Fileviez Perez, Pavel E-mail: fileviez@physics.wisc.edu
2008-08-15
The possibility of explaining the baryon asymmetry in the Universe through the leptogenesis mechanism in the context of adjoint SU(5) is investigated. In this model neutrino masses are generated through the type I and type III seesaw mechanisms, and the field responsible for the type III seesaw, called {rho}{sub 3}, generates the B-L asymmetry needed to satisfy the observed value of the baryon asymmetry in the Universe. We find that the CP asymmetry originates only from the vertex correction, since the self-energy contribution is not present. When neutrino masses have a normal hierarchy, successful leptogenesis is possible for 10{sup 11} GeV{approx}
Effect of the acoustic environment on adjoint sound speed inversions
NASA Astrophysics Data System (ADS)
Richards, Edward
The recent prevalence of low cost robotic platforms such as oceanographic gliders has increased the availability of long-term measurements of the ocean environment. Gliders can take direct measurements of the ocean sound speed environment, which is of interest in many ocean acoustic problems, including source localization and tomography. These measurements, however, have a low spatial-temporal resolution that makes them difficult to use directly. These measurements have the potential to provide an accurate environmental parameterization for acoustic inversions, which could in turn be used to measure the sound speed field at a much higher spatial-temporal resolution. This study uses glider measurements to provide the environmental parameterization used in the adjoint inversion method. The adjoint method calculates the gradient of a cost function describing the mismatch between observed data and acoustic model predictions with respect to the ocean sound speed. This gradient is a measure of how changing the sound speed at any point in the acoustic environment would affect this misfit. This cost function and its gradient information is then used as inputs to a numerical optimization routine, which efficiently finds a local minimum. There are two challenges of this method addressed in this study; the first is restricting the search space of this inversion. Proper parameterization of the inversion will ensure that the local minimum found in the numerical optimization routine is the correct result of the inversion. This parameterization allows for the combination of the relative strengths of both methods of measuring the sound speed field, the robust direct measurement of the glider and the near instantaneous result of an acoustic inversion. A covariance matrix is created from glider measurements of the range dependent sound speed field, which is then decomposed into an empirical orthogonal function (EOF) base. The mean profile and the significant EOF bases then form the
NASA Astrophysics Data System (ADS)
Christensen, Walter James
2015-08-01
During an interview at the Niels Bohr Institute David Bohm stated, "according to Einstein, particles should eventually emerge as singularities, or very strong regions of stable pulses of (the gravitational) field" [1]. Starting from this premise, we show spacetime, indeed, manifests stable pulses (n-valued gravitons) that decay into the vacuum energy to generate all three boson masses (including Higgs), as well as heavy-quark mass; and all in precise agreement with the 2010 CODATA report on fundamental constants. Furthermore, our relativized quantum physics approach (RQP) answers to the mystery surrounding dark energy, dark matter, accelerated spacetime, and why ordinary matter dominates over antimatter.
Higgs-induced spectroscopic shifts near strong gravity sources
Onofrio, Roberto
2010-09-15
We explore the consequences of the mass generation due to the Higgs field in strong gravity astrophysical environments. The vacuum expectation value of the Higgs field is predicted to depend on the curvature of spacetime, potentially giving rise to peculiar spectroscopic shifts, named hereafter 'Higgs shifts'. Higgs shifts could be searched through dedicated multiwavelength and multispecies surveys with high spatial and spectral resolution near strong gravity sources such as Sagittarius A* or broad searches for signals due to primordial black holes. The possible absence of Higgs shifts in these surveys should provide limits to the coupling between the Higgs particle and the curvature of spacetime, a topic of interest for a recently proposed Higgs-driven inflationary model. We discuss some conceptual issues regarding the coexistence between the Higgs mechanism and gravity, especially for their different handling of fundamental and composite particles.
Dirac gauginos, R symmetry and the 125 GeV Higgs
Bertuzzo, Enrico; Frugiuele, Claudia; Gregoire, Thomas; Ponton, Eduardo
2015-04-20
We study a supersymmetric scenario with a quasi exact R-symmetry in light of the discovery of a Higgs resonance with a mass of 125 GeV. In such a framework, the additional adjoint superfields, needed to give Dirac masses to the gauginos, contribute both to the Higgs mass and to electroweak precision observables. We then analyze the interplay between the two aspects, finding regions in parameter space in which the contributions to the precision observables are under control and a 125 GeV Higgs boson can be accommodated. Furthermore, we estimate the fine-tuning of the model finding regions of the parameter space still unexplored by the LHC with a fine-tuning considerably improved with respect to the minimal supersymmetric scenario. In particular, sizable non-holomorphic (non-supersoft) adjoints masses are required to reduce the fine-tuning.
Dirac gauginos, R symmetry and the 125 GeV Higgs
Bertuzzo, Enrico; Frugiuele, Claudia; Gregoire, Thomas; ...
2015-04-20
We study a supersymmetric scenario with a quasi exact R-symmetry in light of the discovery of a Higgs resonance with a mass of 125 GeV. In such a framework, the additional adjoint superfields, needed to give Dirac masses to the gauginos, contribute both to the Higgs mass and to electroweak precision observables. We then analyze the interplay between the two aspects, finding regions in parameter space in which the contributions to the precision observables are under control and a 125 GeV Higgs boson can be accommodated. Furthermore, we estimate the fine-tuning of the model finding regions of the parameter spacemore » still unexplored by the LHC with a fine-tuning considerably improved with respect to the minimal supersymmetric scenario. In particular, sizable non-holomorphic (non-supersoft) adjoints masses are required to reduce the fine-tuning.« less
Adjoint Optimization of Wind Plant Layouts
King, Ryan N.; Dykes, Katherine; Graf, Peter; ...
2016-08-31
Using adjoint optimization and three-dimensional Reynolds-averaged Navier Stokes (RANS) simulations, we present a new gradient-based approach for optimally siting wind turbines within utility-scale wind plants. By solving the adjoint equations of the flow model, the gradients needed for optimization are found at a cost that is independent of the number of control variables, thereby permitting optimization of large wind plants with many turbine locations. Moreover, compared to the common approach of superimposing prescribed wake deficits onto linearized flow models, the computational efficiency of the adjoint approach allows the use of higher-fidelity RANS flow models which can capture nonlinear turbulent flowmore » physics within a wind plant. The RANS flow model is implemented in the Python finite element package FEniCS and the derivation of the adjoint equations is automated within the dolfin-adjoint framework. Gradient-based optimization of wind turbine locations is demonstrated on idealized test cases that reveal new optimization heuristics such as rotational symmetry, local speedups, and nonlinear wake curvature effects. Layout optimization is also demonstrated on more complex wind rose shapes, including a full annual energy production (AEP) layout optimization over 36 inflow directions and 5 windspeed bins.« less
Adjoint Optimization of Wind Plant Layouts
King, Ryan N.; Dykes, Katherine; Graf, Peter; Hamlington, Peter E.
2016-08-31
Using adjoint optimization and three-dimensional Reynolds-averaged Navier Stokes (RANS) simulations, we present a new gradient-based approach for optimally siting wind turbines within utility-scale wind plants. By solving the adjoint equations of the flow model, the gradients needed for optimization are found at a cost that is independent of the number of control variables, thereby permitting optimization of large wind plants with many turbine locations. Moreover, compared to the common approach of superimposing prescribed wake deficits onto linearized flow models, the computational efficiency of the adjoint approach allows the use of higher-fidelity RANS flow models which can capture nonlinear turbulent flow physics within a wind plant. The RANS flow model is implemented in the Python finite element package FEniCS and the derivation of the adjoint equations is automated within the dolfin-adjoint framework. Gradient-based optimization of wind turbine locations is demonstrated on idealized test cases that reveal new optimization heuristics such as rotational symmetry, local speedups, and nonlinear wake curvature effects. Layout optimization is also demonstrated on more complex wind rose shapes, including a full annual energy production (AEP) layout optimization over 36 inflow directions and 5 windspeed bins.
Double-difference adjoint seismic tomography
NASA Astrophysics Data System (ADS)
Yuan, Yanhua O.; Simons, Frederik J.; Tromp, Jeroen
2016-09-01
We introduce a `double-difference' method for the inversion for seismic wave speed structure based on adjoint tomography. Differences between seismic observations and model predictions at individual stations may arise from factors other than structural heterogeneity, such as errors in the assumed source-time function, inaccurate timings and systematic uncertainties. To alleviate the corresponding non-uniqueness in the inverse problem, we construct differential measurements between stations, thereby reducing the influence of the source signature and systematic errors. We minimize the discrepancy between observations and simulations in terms of the differential measurements made on station pairs. We show how to implement the double-difference concept in adjoint tomography, both theoretically and practically. We compare the sensitivities of absolute and differential measurements. The former provide absolute information on structure along the ray paths between stations and sources, whereas the latter explain relative (and thus higher resolution) structural variations in areas close to the stations. Whereas in conventional tomography a measurement made on a single earthquake-station pair provides very limited structural information, in double-difference tomography one earthquake can actually resolve significant details of the structure. The double-difference methodology can be incorporated into the usual adjoint tomography workflow by simply pairing up all conventional measurements; the computational cost of the necessary adjoint simulations is largely unaffected. Rather than adding to the computational burden, the inversion of double-difference measurements merely modifies the construction of the adjoint sources for data assimilation.
NASA Astrophysics Data System (ADS)
Mankoč Borštnik, Norma Susana
2015-03-01
Most physicists declare the Higgs as the last missing particle to be confirmed. But can this at all be true? Shouldn't we understand the origin of families before being able to understand the origin of the Yukawa couplings, for the explanation of which additional scalar fields are needed? The spin-charge-family theory is offering a possible explanation for the origin of families, for several scalar fields manifesting effectively at low energies as the Higgs and the Yukawa couplings, for the fact that the scalar fields are doublets with respect to the weak charge, while they are triplets with respect to the family groups, and also for other assumptions of the standard model. The theory predicts at the observable regime two decoupled groups of four families. The fourth family, coupled to the measured three, will be observed at the LHC. The fifth family is explaining the dark matter. The accuracy with which the fourth family masses can in this theory be predicted depends strongly on the accuracy with which the mixing 3 × 3 sub matrices of the quark and lepton mixing matrices are measured.
Adjoint variational methods in nonconservative stability problems.
NASA Technical Reports Server (NTRS)
Prasad, S. N.; Herrmann, G.
1972-01-01
A general nonself-adjoint eigenvalue problem is examined and it is shown that the commonly employed approximate methods, such as the Galerkin procedure, the method of weighted residuals and the least square technique lack variational descriptions. When used in their previously known forms they do not yield stationary eigenvalues and eigenfunctions. With the help of an adjoint system, however, several analogous variational descriptions may be developed and it is shown in the present study that by properly restating the method of least squares, stationary eigenvalues may be obtained. Several properties of the adjoint eigenvalue problem, known only for a restricted group, are shown to exist for the more general class selected for study.
On the Concepts of Vacuum and Mass and the Search for Higgs
NASA Astrophysics Data System (ADS)
Okun, L. B.
2012-12-01
This review gives some recollections on the recent history of the concepts of vacuum and mass and the search for higgs. According to the widely spread terminology, the Higgs field permeates vacuum and serves as the origin of masses of all fundamental particles including the Higgs boson — the higgs.
Adjoint-Based Uncertainty Quantification with MCNP
Seifried, Jeffrey E.
2011-09-01
This work serves to quantify the instantaneous uncertainties in neutron transport simulations born from nuclear data and statistical counting uncertainties. Perturbation and adjoint theories are used to derive implicit sensitivity expressions. These expressions are transformed into forms that are convenient for construction with MCNP6, creating the ability to perform adjoint-based uncertainty quantification with MCNP6. These new tools are exercised on the depleted-uranium hybrid LIFE blanket, quantifying its sensitivities and uncertainties to important figures of merit. Overall, these uncertainty estimates are small (< 2%). Having quantified the sensitivities and uncertainties, physical understanding of the system is gained and some confidence in the simulation is acquired.
Adjoint-Based Uncertainty Quantification with MCNP
NASA Astrophysics Data System (ADS)
Seifried, Jeffrey Edwin
This work serves to quantify the instantaneous uncertainties in neutron transport simulations born from nuclear data and statistical counting uncertainties. Perturbation and adjoint theories are used to derive implicit sensitivity expressions. These expressions are transformed into forms that are convenient for construction with MCNP6, creating the ability to perform adjoint-based uncertainty quantification with MCNP6. These new tools are exercised on the depleted-uranium hybrid LIFE blanket, quantifying its sensitivities and uncertainties to important figures of merit. Overall, these uncertainty estimates are small (< 2%). Having quantified the sensitivities and uncertainties, physical understanding of the system is gained and some confidence in the simulation is acquired.
Invisible decays in Higgs boson pair production
NASA Astrophysics Data System (ADS)
Banerjee, Shankha; Batell, Brian; Spannowsky, Michael
2017-02-01
Observation of Higgs pair production is an important long term objective of the LHC physics program as it will shed light on the scalar potential of the Higgs field and the nature of electroweak symmetry breaking. While numerous studies have examined the impact of new physics on di-Higgs production, little attention has been given to the well-motivated possibility of exotic Higgs decays in this channel. Here we investigate the consequences of exotic invisible Higgs decays in di-Higgs production. We outline a search sensitive to such invisible decays in the b b ¯+ ET channel. We demonstrate that probing invisible branching ratios of order 10% during the LHC's high-luminosity run will be challenging, but in resonance enhanced di-Higgs production, this final state can become crucial to establish the existence of physics beyond the Standard Model at collider energies. We also briefly discuss the outlook for other exotic Higgs decay modes and the potential to observe such exotic decays in the di-Higgs channel.
NASA Astrophysics Data System (ADS)
Moore, A. M.; Dilorenzo, E.; Arango, H. G.; Lewis, C. V.; Powell, T. M.; Miller, A. J.; Cornuelle, B. D.
2005-12-01
The adjoint of the tangent linear version of the Regional Ocean Modeling System (ROMS) coupled to a four component nitrogen-based trophic model (NPZD) has been used to explore the sensitivity of various physical and biological aspects of the southern arm of the California Current system to linear variations in the physical and biological attributes of the system. The aspects of the system of interest are characterized by suitably defined indices of variability that include measures of coastal upwelling, eddy kinetic energy, and biological tracer concentrations. The adjoint approach is particularly well suited to this kind of analysis because all of the model linear sensitivities can be computed from a single integration of the adjoint model for each index. The adjoint model provides two- and three-dimensional, time-dependent fields of sensitivity from which clear signatures of processes such as advection and instability can be identified. By comparing the sensitivities that arise from perturbing different physical variables in an appropriate way, the relative importance of different physical and biological processes and their potential to control a chosen index can be determined. We will show examples of such adjoint sensitivity analyses for the coupled physical-biological model computed in this way, and discuss their implications.
Gauge-Higgs EW and grand unification
NASA Astrophysics Data System (ADS)
Hosotani, Yutaka
2016-07-01
Four-dimensional Higgs field is identified with the extra-dimensional component of gauge potentials in the gauge-Higgs unification scenario. SO(5) × U(1) gauge-Higgs EW unification in the Randall-Sundrum warped space is successful at low energies. The Higgs field appears as an Aharonov-Bohm phase 𝜃H in the fifth dimension. Its mass is generated at the quantum level and is finite. The model yields almost the same phenomenology as the standard model for 𝜃H < 0.1, and predicts Z‧ bosons around 6-10 TeV with very broad widths. The scenario is generalized to SO(11) gauge-Higgs grand unification. Fermions are introduced in the spinor and vector representations of SO(11). Proton decay is naturally forbidden.
Gauge-Higgs EW and Grand Unification
NASA Astrophysics Data System (ADS)
Hosotani, Yutaka
Four-dimensional Higgs field is identified with the extra-dimensional component of gauge potentials in the gauge-Higgs unifiation scenario. SO(5) × U(1) gauge-Higgs EW unification in the Randall-Sundrum warped space is successful at low energies. The Higgs field appears as an Aharonov-Bohm phase θH in the fifth dimension. Its mass is generated at the quantum level and is finite. The model yields almost the same phenomenology as the standard model for θH < 0.1, and predicts Z' bosons around 6-10 TeV with very broad widths. The scenario is generalized to SO(11) gauge-Higgs grand unification. Fermions are introduced in the spinor and vector representations of SO(11). Proton decay is naturally forbidden.
Higgs-portal assisted Higgs inflation with a sizeable tensor-to-scalar ratio
NASA Astrophysics Data System (ADS)
Kim, Jinsu; Ko, Pyungwon; Park, Wan-Il
2017-02-01
We show that the Higgs portal interactions involving extra dark Higgs field can save generically the original Higgs inflation of the standard model (SM) from the problem of a deep non-SM vacuum in the SM Higgs potential. Specifically, we show that such interactions disconnect the top quark pole mass from inflationary observables and allow multi-dimensional parameter space to save the Higgs inflation, thanks to the additional parameters (the dark Higgs boson mass mphi, the mixing angle α between the SM Higgs H and dark Higgs Φ, and the mixed quartic coupling) affecting RG-running of the Higgs quartic coupling. The effect of Higgs portal interactions may lead to a larger tensor-to-scalar ratio, 0.08 lesssim r lesssim 0.1, by adjusting relevant parameters in wide ranges of α and mphi, some region of which can be probed at future colliders. Performing a numerical analysis we find an allowed region of parameters, matching the latest Planck data.
Postinflationary vacuum instability and Higgs-inflaton couplings
NASA Astrophysics Data System (ADS)
Enqvist, Kari; Karčiauskas, Mindaugas; Lebedev, Oleg; Rusak, Stanislav; Zatta, Marco
2016-11-01
The Higgs-inflaton coupling plays an important role in the Higgs field dynamics in the early Universe. Even a tiny coupling generated at loop level can have a dramatic effect on the fate of the electroweak vacuum. Such Higgs-inflaton interaction is present both at the trilinear and quartic levels in realistic reheating models. In this work, we examine the Higgs dynamics during the preheating epoch, focusing on the effects of the parametric and tachyonic resonances. We use lattice simulations and other numerical tools in our studies. We find that the resonances can induce large fluctuations of the Higgs field which destabilize the electroweak vacuum. Our considerations thus provide an upper bound on quartic and trilinear interactions between the Higgs and the inflaton. We conclude that there exists a favorable range of the couplings within which the Higgs field is stabilized during both inflation and preheating epochs.
Postinflationary vacuum instability and Higgs-inflaton couplings
Enqvist, Kari; Karčiauskas, Mindaugas; Lebedev, Oleg; Rusak, Stanislav; Zatta, Marco
2016-11-11
The Higgs-inflaton coupling plays an important role in the Higgs field dynamics in the early Universe. Even a tiny coupling generated at loop level can have a dramatic effect on the fate of the electroweak vacuum. Such Higgs-inflaton interaction is present both at the trilinear and quartic levels in realistic reheating models. In this work, we examine the Higgs dynamics during the preheating epoch, focusing on the effects of the parametric and tachyonic resonances. We use lattice simulations and other numerical tools in our studies. We find that the resonances can induce large fluctuations of the Higgs field which destabilize the electroweak vacuum. Our considerations thus provide an upper bound on quartic and trilinear interactions between the Higgs and the inflaton. We conclude that there exists a favorable range of the couplings within which the Higgs field is stabilized during both inflation and preheating epochs.
Spacetime Curvature and Higgs Stability after Inflation.
Herranen, M; Markkanen, T; Nurmi, S; Rajantie, A
2015-12-11
We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.
Schafer-Nameki, Sakura; Tamarit, Carlos; Torroba, Gonzalo; /SLAC /Santa Barbara, KITP
2010-08-26
We construct composite Higgs models admitting a weakly coupled Seiberg dual description. We focus on the possibility that only the up-type Higgs is an elementary field, while the down-type Higgs arises as a composite hadron. The model, based on a confining SQCD theory, breaks supersymmetry and electroweak symmetry dynamically and calculably. This simultaneously solves the {mu}/B{sub {mu}} problem and explains the smallness of the bottom and tau masses compared to the top mass. The proposal is then applied to a class of models where the same confining dynamics is used to generate the Standard Model flavor hierarchy by quark and lepton compositeness. This provides a unified framework for flavor, supersymmetry breaking and electroweak physics. The weakly coupled dual is used to explicitly compute the MSSM parameters in terms of a few microscopic couplings, giving interesting relations between the electroweak and soft parameters. The RG evolution down to the TeV scale is obtained and salient phenomenological predictions of this class of 'single-sector' models are discussed.
Adjoint-based constrained topology optimization for viscous flows, including heat transfer
NASA Astrophysics Data System (ADS)
Kontoleontos, E. A.; Papoutsis-Kiachagias, E. M.; Zymaris, A. S.; Papadimitriou, D. I.; Giannakoglou, K. C.
2013-08-01
In fluid mechanics, topology optimization is used for designing flow passages, connecting predefined inlets and outlets, with optimal performance based on selected criteria. In this article, the continuous adjoint approach to topology optimization in incompressible ducted flows with heat transfer is presented. A variable porosity field, to be determined during the optimization, is the means to define the optimal topology. The objective functions take into account viscous losses and the amount of heat transfer. Turbulent flows are handled using the Spalart-Allmaras model and the proposed adjoint is exact, i.e. the adjoint to the turbulence model equation is formulated and solved, too. This is an important novelty in this article which extends the porosity-based method to account for heat transfer flow problems in turbulent flows. In problems such as the design of manifolds, constraints on the outlet flow direction, rates and mean outlet temperatures are imposed.
Fully automatic adjoints: a robust and efficient mechanism for generating adjoint ocean models
NASA Astrophysics Data System (ADS)
Ham, D. A.; Farrell, P. E.; Funke, S. W.; Rognes, M. E.
2012-04-01
The problem of generating and maintaining adjoint models is sufficiently difficult that typically only the most advanced and well-resourced community ocean models achieve it. There are two current technologies which each suffer from their own limitations. Algorithmic differentiation, also called automatic differentiation, is employed by models such as the MITGCM [2] and the Alfred Wegener Institute model FESOM [3]. This technique is very difficult to apply to existing code, and requires a major initial investment to prepare the code for automatic adjoint generation. AD tools may also have difficulty with code employing modern software constructs such as derived data types. An alternative is to formulate the adjoint differential equation and to discretise this separately. This approach, known as the continuous adjoint and employed in ROMS [4], has the disadvantage that two different model code bases must be maintained and manually kept synchronised as the model develops. The discretisation of the continuous adjoint is not automatically consistent with that of the forward model, producing an additional source of error. The alternative presented here is to formulate the flow model in the high level language UFL (Unified Form Language) and to automatically generate the model using the software of the FEniCS project. In this approach it is the high level code specification which is differentiated, a task very similar to the formulation of the continuous adjoint [5]. However since the forward and adjoint models are generated automatically, the difficulty of maintaining them vanishes and the software engineering process is therefore robust. The scheduling and execution of the adjoint model, including the application of an appropriate checkpointing strategy is managed by libadjoint [1]. In contrast to the conventional algorithmic differentiation description of a model as a series of primitive mathematical operations, libadjoint employs a new abstraction of the simulation
The problem with false vacuum Higgs inflation
NASA Astrophysics Data System (ADS)
Fairbairn, Malcolm; Grothaus, Philipp; Hogan, Robert
2014-06-01
We investigate the possibility of using the only known fundamental scalar, the Higgs, as an inflaton with minimal coupling to gravity. The peculiar appearance of a plateau or a false vacuum in the renormalised effective scalar potential suggests that the Higgs might drive inflation. For the case of a false vacuum we use an additional singlet scalar field, motivated by the strong CP problem, and its coupling to the Higgs to lift the barrier allowing for a graceful exit from inflation by mimicking hybrid inflation. We find that this scenario is incompatible with current measurements of the Higgs mass and the QCD coupling constant and conclude that the Higgs can only be the inflaton in more complicated scenarios.
Examining Tropical Cyclone - Kelvin Wave Interactions using Adjoint Diagnostics
NASA Astrophysics Data System (ADS)
Reynolds, C. A.; Doyle, J. D.; Hong, X.
2015-12-01
Adjoint-based tools can provide valuable insight into the mechanisms that influence the evolution and predictability of atmospheric phenomena, as they allow for the efficient and rigorous computation of forecast sensitivity to changes in the initial state. We apply adjoint-based tools from the non-hydrostatic Coupled Atmosphere/Ocean Mesoscale Prediction System (COAMPS) to explore the initial-state sensitivity and interactions between a tropical cyclone and atmospheric equatorial waves associated with the Madden Julian Oscillation (MJO) in the Indian Ocean during the DYNAMO field campaign. The development of Tropical Cyclone 5 (TC05) coincided with the passage of an equatorial Kelvin wave and westerly wind burst associated with an MJO that developed in the Indian Ocean in late November 2011, but it was unclear if and how one affected the other. COAMPS 24-h and 36-h adjoint sensitivities are analyzed for both TC05 and the equatorial waves to understand how the evolution of each system is sensitive to the other. The sensitivity of equatorial westerlies in the western Indian Ocean on 23 November shares characteristics with the classic Gill (1980) Rossby and Kelvin wave response to symmetric heating about the equator, including symmetric cyclonic circulations to the north and south of the westerlies, and enhanced heating in the area of convergence between the equatorial westerlies and easterlies. In addition, there is sensitivity in the Bay of Bengal associated with the cyclonic circulation that eventually develops into TC05. At the same time, the developing TC05 system shows strongest sensitivity to local wind and heating perturbations, but sensitivity to the equatorial westerlies is also clear. On 24 November, when the Kelvin wave is immediately south of the developing tropical cyclone, both phenomena are sensitive to each other. On 25 November TC05 no longer shows sensitivity to the Kelvin wave, while the Kelvin Wave still exhibits some weak sensitivity to TC05. In
Higgs boson masses in supersymmetric models
Berger, M.S.
1991-04-01
Imposing supersymmetry on a Higgs potential constrains the parameters that define the potential. In supersymmetric extensions to the stranded model containing only Higgs SU(2){sub L} doublets there exist Higgs boson mass sum rules and bounds on the Higgs masses at tree level. The prescription for renormalizing these sum rules is derived. An explicit calculation is performed in the minimal supersymmetric extension to the standard model (MSSM). In this model at tree level the mass sum rule is M{sub H}{sup 2} + M{sub h}{sup 2} = M{sub A}{sup 2} + M{sub Z}{sup 2}. The results indicate that large corrections to the sum rules may arise from heavy matter fields, e.g. a heavy top quark. Squarks significantly heavier than their fermionic partners contribute large contributions when mixing occurs in the squark sector. These large corrections result from squark-Higgs couplings that become large in this limit. Contributions to individual Higgs boson masses that are quadratic in the squark masses cancel in the sum rule. Thus the naturalness constraint on Higgs boson masses is hidden in the combination of Higgs boson masses that comprise the sum rule. 39 refs., 13 figs.
NASA Astrophysics Data System (ADS)
Bentov, Yoni; Zee, A.
2013-11-01
We study the LHC phenomenology of a general class of "Private Higgs" (PH) models, in which fermions obtain their masses from their own Higgs doublets with {O}(1) Yukawa couplings, and the mass hierarchy is translated into a dynamical chain of vacuum expectation values. This is accomplished by introducing a number of light gauge-singlet scalars, the "darkons," some of which could play the role of dark matter. These models allow for substantial modifications to the decays of the lightest Higgs boson, for instance through mixing with TeV-scale PH fields and light darkons: in particular, one could accommodate {O}(10%) flavor-uncorrelated deviations from the SM hf\\bar f vertices with TeV-scale degrees of freedom. We also discuss a new implementation of the PH framework, in which the quark and neutrino mixing angles arise as one-loop corrections to the leading order picture.
Shaposhnikov, Mikhail
2015-01-01
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
The Higgs boson and cosmology.
Shaposhnikov, Mikhail
2015-01-13
I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.
Spectral functions of non-essentially self-adjoint operators
NASA Astrophysics Data System (ADS)
Falomir, H. A.; Pisani, P. A. G.
2012-09-01
One of the many problems to which Dowker devoted his attention is the effect of a conical singularity in the base manifold on the behavior of the quantum fields. In particular, he studied the small-t asymptotic expansion of the heat-kernel trace on a cone and its effects on physical quantities as the Casimir energy. In this paper, we review some peculiar results found in the last decade, regarding the appearance of non-standard powers of t, and even negative integer powers of log t, in this asymptotic expansion for the self-adjoint extensions of some symmetric operators with singular coefficients. Similarly, we show that the ζ-function associated with these self-adjoint extensions presents an unusual analytic structure. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker’s 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.
NASA Astrophysics Data System (ADS)
Roberts, Alex
2016-08-01
class of scenarios at the LHC. Comparing limits, we find that current LHC results only exclude regions in parameter space which were already disfavored by precision electroweak data.. Recent LHC data, together with the electroweak naturalness argument, suggest that the top squarks may be significantly lighter than the other sfermions. We present supersymmetric models in which such a split spectrum is obtained through ''geometries'': being ''close to'' electroweak symmetry breaking implies being ''away from'' supersymmetry breaking, and vice versa. In particular, we present models in 5D warped spacetime, in which supersymmetry breaking and Higgs fields are located on the ultraviolet and infrared branes, respectively, and the top multiplets are localized to the infrared brane. The hierarchy of the Yukawa matrices can be obtained while keeping near flavor degeneracy between the first two generation sfermions, avoiding stringent constraints from flavor and CP violation. Through the AdS/CFT correspondence, the models can be interpreted as purely 4D theories in which the top and Higgs multiplets are composites of some strongly interacting sector exhibiting nontrivial dynamics at a low energy. Because of the compositeness of the Higgs and top multiplets, Landau pole constraints for the Higgs and top couplings apply only up to the dynamical scale, allowing for a relatively heavy Higgs boson, including mh = 125 GeV as suggested by the recent LHC data. We analyze electroweak symmetry breaking for a well-motivated subset of these models, and find that fine-tuning in electroweak symmetry breaking is indeed ameliorated. We also discuss a flat space realization of the scenario in which supersymmetry is broken by boundary conditions, with the top multiplets localized to a brane while other matter multiplets delocalized in the bulk.
Optimal Multistage Algorithm for Adjoint Computation
Aupy, Guillaume; Herrmann, Julien; Hovland, Paul; Robert, Yves
2016-01-01
We reexamine the work of Stumm and Walther on multistage algorithms for adjoint computation. We provide an optimal algorithm for this problem when there are two levels of checkpoints, in memory and on disk. Previously, optimal algorithms for adjoint computations were known only for a single level of checkpoints with no writing and reading costs; a well-known example is the binomial checkpointing algorithm of Griewank and Walther. Stumm and Walther extended that binomial checkpointing algorithm to the case of two levels of checkpoints, but they did not provide any optimality results. We bridge the gap by designing the first optimal algorithm in this context. We experimentally compare our optimal algorithm with that of Stumm and Walther to assess the difference in performance.
Adjoint sensitivity studies of loop current and eddy shedding in the Gulf of Mexico
NASA Astrophysics Data System (ADS)
Gopalakrishnan, Ganesh; Cornuelle, Bruce D.; Hoteit, Ibrahim
2013-07-01
the current, while sensitivities to SSH generally extend to deeper layers and propagate more slowly. The adjoint sensitivity to relative vorticity deduced from the sensitivities to velocity fields suggests that advection of cyclonic (positive) relative vorticity anomalies from the YC or the LCFEs accelerate the LC eddy separation. Forward model perturbation experiments were performed to complement and check the adjoint sensitivity analysis as well as sampling the predictability and nonlinearity of the LC evolution. The model and its adjoint can be used in four-dimensional variational assimilation (4D-VAR) to produce dynamically consistent ocean state estimates for analysis and forecasts of the circulation of the GoM.
Chiral phases of fundamental and adjoint quarks
Natale, A. A.
2016-01-22
We consider a QCD chiral symmetry breaking model where the gap equation contains an effective confining propagator and a dressed gluon propagator with a dynamically generated mass. This model is able to explain the ratios between the chiral transition and deconfinement temperatures in the case of fundamental and adjoint quarks. It also predicts the recovery of the chiral symmetry for a large number of quarks (n{sub f} ≈ 11 – 13) in agreement with lattice data.
Chiral phases of fundamental and adjoint quarks
NASA Astrophysics Data System (ADS)
Natale, A. A.
2016-01-01
We consider a QCD chiral symmetry breaking model where the gap equation contains an effective confining propagator and a dressed gluon propagator with a dynamically generated mass. This model is able to explain the ratios between the chiral transition and deconfinement temperatures in the case of fundamental and adjoint quarks. It also predicts the recovery of the chiral symmetry for a large number of quarks (nf ≈ 11 - 13) in agreement with lattice data.
Maxwell-Higgs equation on higher dimensional static curved spacetimes
Mulyanto; Akbar, Fiki Taufik Gunara, Bobby Eka
2015-09-30
In this paper we consider a class of solutions of Maxwell-Higgs equation in higher dimensional static curved spacetimes called Schwarzchild de-Sitter spacetimes. We obtain the general form of the electric fields and magnetic fields in background Schwarzchild de-Sitter spacetimes. However, determining the interaction between photons with the Higgs scalar fields is needed further studies.
NASA Astrophysics Data System (ADS)
Holzner, André G.
2016-12-01
This article reviews recent measurements of the properties of the standard model (SM) Higgs boson using data recorded with the CMS detector at the LHC: its mass, width and couplings to other SM particles. We also summarise highlights from searches for new physical phenomena in the Higgs sector as they are proposed in many extensions of the SM: flavour violating and invisible decay modes, resonances decaying into Higgs bosons and searches for additional Higgs bosons.
Supersymmetric descendants of self-adjointly extended quantum mechanical Hamiltonians
NASA Astrophysics Data System (ADS)
Al-Hashimi, M. H.; Salman, M.; Shalaby, A.; Wiese, U.-J.
2013-10-01
We consider the descendants of self-adjointly extended Hamiltonians in supersymmetric quantum mechanics on a half-line, on an interval, and on a punctured line or interval. While there is a 4-parameter family of self-adjointly extended Hamiltonians on a punctured line, only a 3-parameter sub-family has supersymmetric descendants that are themselves self-adjoint. We also address the self-adjointness of an operator related to the supercharge, and point out that only a sub-class of its most general self-adjoint extensions is physical. Besides a general characterization of self-adjoint extensions and their supersymmetric descendants, we explicitly consider concrete examples, including a particle in a box with general boundary conditions, with and without an additional point interaction. We also discuss bulk-boundary resonances and their manifestation in the supersymmetric descendant.
Topological Physics of Little Higgs Bosons
Hill, Christopher T.; Hill, Richard J.; /Fermilab
2007-01-01
Topological interactions will generally occur in composite Higgs or Little Higgs theories, extra-dimensional gauge theories in which A5 plays the role of a Higgs boson, and among the pNGB's of technicolor. This phenomena arises from the chiral and anomaly structure of the underlying UV completion theory, and/or through chiral delocalization in higher dimensions. These effects are described by a full Wess-Zumino-Witten term involving gauge fields and pNGB's. We give a general discussion of these interactions, some of which may have novel signatures at future colliders, such as the LHC and ILC.
Generalized uncertainty principle and self-adjoint operators
Balasubramanian, Venkat; Das, Saurya; Vagenas, Elias C.
2015-09-15
In this work we explore the self-adjointness of the GUP-modified momentum and Hamiltonian operators over different domains. In particular, we utilize the theorem by von-Neumann for symmetric operators in order to determine whether the momentum and Hamiltonian operators are self-adjoint or not, or they have self-adjoint extensions over the given domain. In addition, a simple example of the Hamiltonian operator describing a particle in a box is given. The solutions of the boundary conditions that describe the self-adjoint extensions of the specific Hamiltonian operator are obtained.
Use of an adjoint model for finding triggers for Alpine lee cyclogenesis
NASA Technical Reports Server (NTRS)
Vukicevic, Tomislava; Raeder, Kevin
1995-01-01
The authors propose a new procedure, designated the adjoint-based genesis diagnostic (AGD) procedure, for studying triggering mechanisms and the subsequent genesis of the synoptic phenomena of interest. This procedure makes use of a numerical model sensitivity to initial conditions and the nonlinear evolution of the initial perturbations that are designed using this sensitivity. The model sensitivity is evaluated using the associated adjoint model. This study uses the dry version of the National Center for Atmospheric Research Mesoscale Adjoint Modeling System (MAMS) for the numerical experiments. The authors apply the AGD procedure to two cases of Alpine lee cyclogenesis that were observed during the Alpine Experiment special observations period. The results show that the sensitivity fields that are produced by the adjoint model and the associated initial perturbations are readily related to the probable triggering mechanisms for these cyclones. Additionally, the nonlinear evolution of these initial perturbations points toward the physical processes involved in the lee cyclone formation. The AGD experiments for a weak cyclone case indicate that the MAMS forecast model has an underrepresented topographic forcing due to the sigma vertical coordinate and that this model error can be compensated by adjustments in the initial conditions that are related to the triggering mechanisms, which is not associated with the topographic blocking mechanism.
Probing the Higgs vacuum with general relativity
NASA Technical Reports Server (NTRS)
Mannheim, Philip D.; Kazanas, Demosthenes
1991-01-01
It is shown that the structure of the Higgs vacuum can be revealed in gravitational experiments which probe the Schwarzschild geometry to only one order in MG/r beyond that needed for the classical tests of general relativity. The possibility that deviations from the conventional geometry are at least theoretically conceivable is explored. The deviations obtained provide a diagnostic test for searching for the existence of macroscopic scalar fields and open up the possiblity for further exploring the Higgs mechanism.
Elementary operators on self-adjoint operators
NASA Astrophysics Data System (ADS)
Molnar, Lajos; Semrl, Peter
2007-03-01
Let H be a Hilbert space and let and be standard *-operator algebras on H. Denote by and the set of all self-adjoint operators in and , respectively. Assume that and are surjective maps such that M(AM*(B)A)=M(A)BM(A) and M*(BM(A)B)=M*(B)AM*(B) for every pair , . Then there exist an invertible bounded linear or conjugate-linear operator and a constant c[set membership, variant]{-1,1} such that M(A)=cTAT*, , and M*(B)=cT*BT, .
Adjoint sensitivity analysis of an ultrawideband antenna
Stephanson, M B; White, D A
2011-07-28
The frequency domain finite element method using H(curl)-conforming finite elements is a robust technique for full-wave analysis of antennas. As computers become more powerful, it is becoming feasible to not only predict antenna performance, but also to compute sensitivity of antenna performance with respect to multiple parameters. This sensitivity information can then be used for optimization of the design or specification of manufacturing tolerances. In this paper we review the Adjoint Method for sensitivity calculation, and apply it to the problem of optimizing a Ultrawideband antenna.
Imaging Earth's Interior Based Upon Adjoint Methods
NASA Astrophysics Data System (ADS)
Tromp, J.; Komatitsch, D.; Liu, Q.; Tape, C.; Maggi, A.
2008-12-01
Modern numerical methods in combination with rapid advances in parallel computing have enabled the simulation of seismic wave propagation in 3D Earth models at unpredcented resolution and accuracy. On a modest PC cluster one can now simulate global seismic wave propagation at periods of 20~s longer accounting for heterogeneity in the crust and mantle, topography, anisotropy, attenuation, fluid-solid interactions, self-gravitation, rotation, and the oceans. On the 'Ranger' system at the Texas Advanced Computing Center one can break the 2~s barrier. By drawing connections between seismic tomography, adjoint methods popular in climate and ocean dynamics, time-reversal imaging, and finite-frequency 'banana-doughnut' kernels, it has been demonstrated that Fréchet derivatives for tomographic and (finite) source inversions in complex 3D Earth models may be obtained based upon just two numerical simulations for each earthquake: one calculation for the current model and a second, 'adjoint', calculation that uses time-reversed signals at the receivers as simultaneous, fictitious sources. The adjoint wavefield is calculated while the regular wavefield is reconstructed on the fly by propagating the last frame of the wavefield saved by a previous forward simulation backward in time. This aproach has been used to calculate sensitivity kernels in regional and global Earth models for various body- and surface-wave arrivals. These kernels illustrate the sensitivity of the observations to the structural parameters and form the basis of 'adjoint tomography'. We use a non-linear conjugate gradient method in combination with a source subspace projection preconditioning technique to iterative minimize the misfit function. Using an automated time window selection algorithm, our emphasis is on matching targeted, frequency-dependent body-wave traveltimes and surface-wave phase anomalies, rather than entire waveforms. To avoid reaching a local minimum in the optimization procedure, we
Discrete and continuous symmetries in multi-Higgs-doublet models
Ferreira, P. M.; Silva, Joao P.
2008-12-01
We consider the Higgs sector of multi-Higgs-doublet models in the presence of simple symmetries relating the various fields. We construct basis-invariant observables which may in principle be used to detect these symmetries for any number of doublets. A categorization of the symmetries into classes is required, which we perform in detail for the case of two and three Higgs doublets.
Basis invariant conditions for supersymmetry in the two-Higgs-doublet model
Ferreira, P. M.; Haber, Howard E.; Silva, Joao P.
2010-07-01
The minimal supersymmetric standard model involves a rather restrictive Higgs potential with two Higgs fields. Recently, the full set of classes of symmetries allowed in the most general two-Higgs-doublet model was identified; these classes do not include the supersymmetric limit as a particular class. Thus, a physically meaningful definition of the supersymmetric limit must involve the interaction of the Higgs sector with other sectors of the theory. Here we show how one can construct basis invariant probes of supersymmetry involving both the Higgs sector and the gaugino-Higgsino-Higgs interactions.
Supersymmetric descendants of self-adjointly extended quantum mechanical Hamiltonians
Al-Hashimi, M.H.; Salman, M.; Shalaby, A.; Wiese, U.-J.
2013-10-15
We consider the descendants of self-adjointly extended Hamiltonians in supersymmetric quantum mechanics on a half-line, on an interval, and on a punctured line or interval. While there is a 4-parameter family of self-adjointly extended Hamiltonians on a punctured line, only a 3-parameter sub-family has supersymmetric descendants that are themselves self-adjoint. We also address the self-adjointness of an operator related to the supercharge, and point out that only a sub-class of its most general self-adjoint extensions is physical. Besides a general characterization of self-adjoint extensions and their supersymmetric descendants, we explicitly consider concrete examples, including a particle in a box with general boundary conditions, with and without an additional point interaction. We also discuss bulk-boundary resonances and their manifestation in the supersymmetric descendant. -- Highlights: •Self-adjoint extension theory and contact interactions. •Application of self-adjoint extensions to supersymmetry. •Contact interactions in finite volume with Robin boundary condition.
Generation of perturbations by means of decoupled equations and their adjoints
NASA Astrophysics Data System (ADS)
Torres Del Castillo, G. F.
1990-10-01
It is shown that the procedure introduced by Wald for constructing solutions of a coupled system of linear partial differential equations from the solution of a single equation, based on the concept of the adjoint of a linear partial differential operator, can be extended to equations involving spinor fields, matrix fields and two or more fields. Some results concerning massless spinor fields are presented and the application of the method to linear perturbations of Yang-Mills fields and of Einstein-Maxwell fields is indicated.
Alignment limit of the NMSSM Higgs sector
Carena, Marcela; Haber, Howard E.; Low, Ian; ...
2016-02-17
The Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) with a Higgs boson of mass 125 GeV can be compatible with stop masses of order of the electroweak scale, thereby reducing the degree of fine-tuning necessary to achieve electroweak symmetry breaking. Moreover, in an attractive region of the NMSSM parameter space, corresponding to the \\alignment limit" in which one of the neutral Higgs fields lies approximately in the same direction in field space as the doublet Higgs vacuum expectation value, the observed Higgs boson is predicted to have Standard- Model-like properties. We derive analytical expressions for the alignment conditions andmore » show that they point toward a more natural region of parameter space for electroweak symmetry breaking, while allowing for perturbativity of the theory up to the Planck scale. Additionally, the alignment limit in the NMSSM leads to a well defined spectrum in the Higgs and Higgsino sectors, and yields a rich and interesting Higgs boson phenomenology that can be tested at the LHC. Here, we discuss the most promising channels for discovery and present several benchmark points for further study.« less
Alignment limit of the NMSSM Higgs sector
Carena, Marcela; Haber, Howard E.; Low, Ian; Shah, Nausheen R.; Wagner, Carlos E. M.
2016-02-17
The Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) with a Higgs boson of mass 125 GeV can be compatible with stop masses of order of the electroweak scale, thereby reducing the degree of fine-tuning necessary to achieve electroweak symmetry breaking. Moreover, in an attractive region of the NMSSM parameter space, corresponding to the \\alignment limit" in which one of the neutral Higgs fields lies approximately in the same direction in field space as the doublet Higgs vacuum expectation value, the observed Higgs boson is predicted to have Standard- Model-like properties. We derive analytical expressions for the alignment conditions and show that they point toward a more natural region of parameter space for electroweak symmetry breaking, while allowing for perturbativity of the theory up to the Planck scale. Additionally, the alignment limit in the NMSSM leads to a well defined spectrum in the Higgs and Higgsino sectors, and yields a rich and interesting Higgs boson phenomenology that can be tested at the LHC. Here, we discuss the most promising channels for discovery and present several benchmark points for further study.
Tsunami waveform inversion by adjoint methods
NASA Astrophysics Data System (ADS)
Pires, Carlos; Miranda, Pedro M. A.
2001-09-01
An adjoint method for tsunami waveform inversion is proposed, as an alternative to the technique based on Green's functions of the linear long wave model. The method has the advantage of being able to use the nonlinear shallow water equations, or other appropriate equation sets, and to optimize an initial state given as a linear or nonlinear function of any set of free parameters. This last facility is used to perform explicit optimization of the focal fault parameters, characterizing the initial sea surface displacement of tsunamigenic earthquakes. The proposed methodology is validated with experiments using synthetic data, showing the possibility of recovering all relevant details of a tsunami source from tide gauge observations, providing that the adjoint method is constrained in an appropriate manner. It is found, as in other methods, that the inversion skill of tsunami sources increases with the azimuthal and temporal coverage of assimilated tide gauge stations; furthermore, it is shown that the eigenvalue analysis of the Hessian matrix of the cost function provides a consistent and useful methodology to choose the subset of independent parameters that can be inverted with a given dataset of observations and to evaluate the error of the inversion process. The method is also applied to real tide gauge series, from the tsunami of the February 28, 1969, Gorringe Bank earthquake, suggesting some reasonable changes to the assumed focal parameters of that event. It is suggested that the method proposed may be able to deal with transient tsunami sources such as those generated by submarine landslides.
Confinement of quarks and valence gluons in SU( N) Yang-Mills-Higgs models
NASA Astrophysics Data System (ADS)
Oxman, L. E.
2013-03-01
In this work, we analyze a class of Yang-Mills models containing adjoint Higgs fields, with SU( N) symmetry spontaneously broken down to Z( N), showing they contain center vortices, Y-junctions formed by them, and junctions where different center vortices are smoothly interpolated by monopole-like configurations. In the context of dual superconductors, these objects represent different states of the gluon field. Center vortices confine quarks to form normal hadron states. The interpolating monopole, which in our model cannot exist as an isolated configuration, is identified with a confined valence gluon. A junction containing a monopole can bind quarks in a color nonsinglet state to form an overall neutral object, identified with a hybrid hadron. These states, formed by quarks bound to a valence gluon, are allowed by QCD, and current experimental collaborations are aimed at identifying them. Finally, considering the general version of the model, based on a compact simple gauge group G, the picture is completed with a heuristic discussion about why it would be natural using as G the dual of the chromoelectric gauge group G e, and external pointlike monopoles to represent the mesonic and baryonic Wilson loops.
Leptogenesis, radiative neutrino masses and inert Higgs triplet dark matter
Lu, Wen-Bin; Gu, Pei-Hong
2016-05-18
We extend the standard model by three types of inert fields including Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic Higgs doublets. In the presence of a softly broken lepton number and an exactly conserved Z{sub 2} discrete symmetry, these inert fields together can mediate a one-loop diagram for a Majorana neutrino mass generation. The heavier inert fields can decay to realize a successful leptogenesis while the lightest inert field can provide a stable dark matter candidate. As an example, we demonstrate the leptogenesis by the inert Higgs doublet decays. We also perform a systematic study on the inert Higgs triplet dark matter scenario where the interference between the gauge and Higgs portal interactions can significantly affect the dark matter properties.
Inflation and the Higgs Scalar
Green, Dan
2014-12-05
This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A simple scalar model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.
Lincoln, Don
2016-11-16
The Higgs boson burst into the public arena on July 4, 2012, when scientists working at the CERN laboratory announced the particle’s discovery. However the initial discovery was a bit tentative, with the need to verify that the discovered particle was, indeed, the Higgs boson. In this video, Fermilab’s Dr. Don Lincoln looks at the data from the perspective of 2016 and shows that more recent analyses further supports the idea that the Higgs boson is what was discovered.
Applying EFT to Higgs pair production in universal extra dimensions
NASA Astrophysics Data System (ADS)
Edelhäuser, Lisa; Knochel, Alexander; Steeger, Thomas
2015-11-01
We investigate single Higgs and Higgs pair production at the LHC in models of Universal Extra Dimensions. After calculating the relevant cross sections, we use the UED model as a testing ground for the Effective Field Theory approach to physics beyond the Standard Model. We show how the UED contributions to Higgs production can be matched to a dimension-6 operator. We then discuss the range of validity of this approach, in particular for Higgs pair production, and determine the sensitivity to the number of KK modes in the loop.
COSMOLOGICAL CONSTRAINTS ON THE HIGGS BOSON MASS
Popa, L. A.; Caramete, A.
2010-11-01
For a robust interpretation of upcoming observations from PLANCK and Large Hadron Collider experiments it is imperative to understand how the inflationary dynamics of a non-minimally coupled Higgs scalar field with gravity may affect the determination of the inflationary observables. We make a full proper analysis of the Wilkinson Microwave Anisotropy Probe, Type Ia supernova distance-redshift relation, and the baryon acoustic oscillations data sets in a context of the non-minimally coupled Higgs inflation field with gravity. For the central value of the top quark pole mass m{sub T} = 171.3 GeV, the fit of the inflation model with a non-minimally coupled Higgs scalar field leads to a Higgs boson mass in the range 143.7 GeV {<=} m{sub H} {<=} 167 GeV (95% CL). We show that the inflation driven by a non-minimally coupled scalar field to the Einstein gravity leads to significant constraints on the scalar spectral index n{sub S} and the tensor-to-scalar ratio R when compared with a tensor with similar constraints to form the standard inflation with a minimally coupled scalar field. We also show that an accurate reconstruction of the Higgs potential in terms of inflationary observables requires an improved accuracy of other parameters of the standard model of particle physics such as the top quark mass and the effective QCD coupling constant.
Sensitivity kernels for viscoelastic loading based on adjoint methods
NASA Astrophysics Data System (ADS)
Al-Attar, David; Tromp, Jeroen
2014-01-01
Observations of glacial isostatic adjustment (GIA) allow for inferences to be made about mantle viscosity, ice sheet history and other related parameters. Typically, this inverse problem can be formulated as minimizing the misfit between the given observations and a corresponding set of synthetic data. When the number of parameters is large, solution of such optimization problems can be computationally challenging. A practical, albeit non-ideal, solution is to use gradient-based optimization. Although the gradient of the misfit required in such methods could be calculated approximately using finite differences, the necessary computation time grows linearly with the number of model parameters, and so this is often infeasible. A far better approach is to apply the `adjoint method', which allows the exact gradient to be calculated from a single solution of the forward problem, along with one solution of the associated adjoint problem. As a first step towards applying the adjoint method to the GIA inverse problem, we consider its application to a simpler viscoelastic loading problem in which gravitationally self-consistent ocean loading is neglected. The earth model considered is non-rotating, self-gravitating, compressible, hydrostatically pre-stressed, laterally heterogeneous and possesses a Maxwell solid rheology. We determine adjoint equations and Fréchet kernels for this problem based on a Lagrange multiplier method. Given an objective functional J defined in terms of the surface deformation fields, we show that its first-order perturbation can be written δ J = int _{MS}K_{η }δ ln η dV +int _{t0}^{t1}int _{partial M}K_{dot{σ }} δ dot{σ } dS dt, where δ ln η = δη/η denotes relative viscosity variations in solid regions MS, dV is the volume element, δ dot{σ } is the perturbation to the time derivative of the surface load which is defined on the earth model's surface ∂M and for times [t0, t1] and dS is the surface element on ∂M. The `viscosity
Enhanced Higgs mass in Compact Supersymmetry
NASA Astrophysics Data System (ADS)
Tobioka, Kohsaku; Kitano, Ryuichiro; Murayama, Hitoshi
2016-04-01
The current LHC results make weak scale supersymmetry difficult due to relatively heavy mass of the discovered Higgs boson and the null results of new particle searches. Geometrical supersymmetry breaking from extra dimensions, Scherk-Schwarz mechanism, is possible to accommodate such situations. A concrete example, the Compact Supersymmetry model, has a compressed spectrum ameliorating the LHC bounds and large mixing in the top and scalar top quark sector with |{A}_t|˜ 2{m}_{tilde{t}} which radiatively raises the Higgs mass. While the zero mode contribution of the model has been considered, in this paper we calculate the Kaluza-Klein tower effect to the Higgs mass. Although such contributions are naively expected to be as small as a percent level for 10 TeV Kaluza-Klein modes, we find the effect significantly enhances the radiative correction to the Higgs quartic coupling by from 10 to 50%. This is mainly because the top quark wave function is pushed out from the brane, which makes the top mass depend on higher powers in the Higgs field. As a result the Higgs mass is enhanced up to 15 GeV from the previous calculation. We also show the whole parameter space is testable at the LHC run II.
New signatures of flavor violating Higgs couplings
NASA Astrophysics Data System (ADS)
Buschmann, Malte; Kopp, Joachim; Liu, Jia; Wang, Xiao-Ping
2016-06-01
We explore several novel LHC signatures arising from quark or lepton flavor violating couplings in the Higgs sector, and we constrain such couplings using LHC data. Since the largest signals are possible in channels involving top quarks or tau leptons, we consider in particular the following flavor violating processes: (1) pp → thh (top plus di-Higgs final state) arising from a dimension six coupling of up-type quarks to three insertions of the Higgs field. We develop a search strategy for this final state and demonstrate that detection is possible at the high luminosity LHC if flavor violating top-up-Higgs couplings are not too far below the current limit. (2) pp → tH 0, where H 0 is the heavy neutral CP-even Higgs boson in a two Higgs doublet model (2HDM). We consider the decay channels H 0 → tu, WW, ZZ, hh and use existing LHC data to constrain the first three of them. For the fourth, we adapt our search for the thh final state, and we demonstrate that in large regions of the parameter space, it is superior to other searches, including searches for flavor violating top quark decays ( t → hq). (3) H 0 → τ μ, again in the context of a 2HDM. This channel is particularly well motivated by the recent CMS excess in h → τ μ, and we use the data from this search to constrain the properties of H 0.
NASA Astrophysics Data System (ADS)
Fang, F.; Pain, C. C.; Gaddard, A. J. H.; de Oliveira, C. R. E.; Piggott, M. D.; Umpleby, A. P.; Copeland, G. J. M.
2003-04-01
There are often uncertain factors in ocean numerical models, e.g. the initial and boundary conditions, parameters. With the introduction of advanced observational techniques, more attention has been given to data assimilation to improve the predictive capabilities of ocean models. The question is how and where best to assimilate the observations for reducing the dependence of solutions on the initial and boundary data and getting a better representation of non-stratified water flows around and over coastal topography. In this investigation, we aim to introduce an adjoint model into the Imperial College Ocean Model (ICOM), which is a 3D nonlinear non-hydrostatic model with mesh adaptivity and optimal Domain Decomposition Method (DDM) parallel solver. By using an unstructured mesh, ICOM can automatically conform to the complicated coastal topography and with mesh adaptivity the resolution can be designed to meet physics demands such as flows in region of high shear and flow separation at coastlines. In the initial stage of this investigation, we discuss various adjoint methods and their consistence. To accelerate the convergence of the gradient calculation and reduce the memory requirement, the numerical techniques: Nonlinear Conjugate Gradient and Check Pointing are introduced. We then apply the adjoint method to 1D nonlinear shallow water and 2D coastal flow past a headland with the inversion of both boundary and initial conditions. We give an initial insight to (1) Effect of data information to be inverted; (2) Role of the nonlinear terms in the inversion; (3) Possibility of adopting non-consistent discretization schemes in the forward and backward adjoint models; (4) Effect of various boundary conditions, e.g. uniform flow and wave/tidal flow.
NASA Astrophysics Data System (ADS)
Dubinin, M. N.; Petrova, E. Yu.
2017-03-01
In the framework of the effective field theory approach to heavy supersymmetry radiative corrections in the Higgs sector of the minimal supersymmetric standard model (MSSM) for the effective potential decomposition up to the dimension-six operators are calculated. Symbolic expressions for the threshold corrections induced by F - and D -soft supersymmetry breaking terms are derived, and the Higgs boson mass spectrum respecting the condition mh=125 GeV for the lightest C P -even scalar is evaluated.
Adjoints and Low-rank Covariance Representation
NASA Technical Reports Server (NTRS)
Tippett, Michael K.; Cohn, Stephen E.
2000-01-01
Quantitative measures of the uncertainty of Earth System estimates can be as important as the estimates themselves. Second moments of estimation errors are described by the covariance matrix, whose direct calculation is impractical when the number of degrees of freedom of the system state is large. Ensemble and reduced-state approaches to prediction and data assimilation replace full estimation error covariance matrices by low-rank approximations. The appropriateness of such approximations depends on the spectrum of the full error covariance matrix, whose calculation is also often impractical. Here we examine the situation where the error covariance is a linear transformation of a forcing error covariance. We use operator norms and adjoints to relate the appropriateness of low-rank representations to the conditioning of this transformation. The analysis is used to investigate low-rank representations of the steady-state response to random forcing of an idealized discrete-time dynamical system.
GPU-Accelerated Adjoint Algorithmic Differentiation.
Gremse, Felix; Höfter, Andreas; Razik, Lukas; Kiessling, Fabian; Naumann, Uwe
2016-03-01
Many scientific problems such as classifier training or medical image reconstruction can be expressed as minimization of differentiable real-valued cost functions and solved with iterative gradient-based methods. Adjoint algorithmic differentiation (AAD) enables automated computation of gradients of such cost functions implemented as computer programs. To backpropagate adjoint derivatives, excessive memory is potentially required to store the intermediate partial derivatives on a dedicated data structure, referred to as the "tape". Parallelization is difficult because threads need to synchronize their accesses during taping and backpropagation. This situation is aggravated for many-core architectures, such as Graphics Processing Units (GPUs), because of the large number of light-weight threads and the limited memory size in general as well as per thread. We show how these limitations can be mediated if the cost function is expressed using GPU-accelerated vector and matrix operations which are recognized as intrinsic functions by our AAD software. We compare this approach with naive and vectorized implementations for CPUs. We use four increasingly complex cost functions to evaluate the performance with respect to memory consumption and gradient computation times. Using vectorization, CPU and GPU memory consumption could be substantially reduced compared to the naive reference implementation, in some cases even by an order of complexity. The vectorization allowed usage of optimized parallel libraries during forward and reverse passes which resulted in high speedups for the vectorized CPU version compared to the naive reference implementation. The GPU version achieved an additional speedup of 7.5 ± 4.4, showing that the processing power of GPUs can be utilized for AAD using this concept. Furthermore, we show how this software can be systematically extended for more complex problems such as nonlinear absorption reconstruction for fluorescence-mediated tomography.
GPU-accelerated adjoint algorithmic differentiation
NASA Astrophysics Data System (ADS)
Gremse, Felix; Höfter, Andreas; Razik, Lukas; Kiessling, Fabian; Naumann, Uwe
2016-03-01
Many scientific problems such as classifier training or medical image reconstruction can be expressed as minimization of differentiable real-valued cost functions and solved with iterative gradient-based methods. Adjoint algorithmic differentiation (AAD) enables automated computation of gradients of such cost functions implemented as computer programs. To backpropagate adjoint derivatives, excessive memory is potentially required to store the intermediate partial derivatives on a dedicated data structure, referred to as the "tape". Parallelization is difficult because threads need to synchronize their accesses during taping and backpropagation. This situation is aggravated for many-core architectures, such as Graphics Processing Units (GPUs), because of the large number of light-weight threads and the limited memory size in general as well as per thread. We show how these limitations can be mediated if the cost function is expressed using GPU-accelerated vector and matrix operations which are recognized as intrinsic functions by our AAD software. We compare this approach with naive and vectorized implementations for CPUs. We use four increasingly complex cost functions to evaluate the performance with respect to memory consumption and gradient computation times. Using vectorization, CPU and GPU memory consumption could be substantially reduced compared to the naive reference implementation, in some cases even by an order of complexity. The vectorization allowed usage of optimized parallel libraries during forward and reverse passes which resulted in high speedups for the vectorized CPU version compared to the naive reference implementation. The GPU version achieved an additional speedup of 7.5 ± 4.4, showing that the processing power of GPUs can be utilized for AAD using this concept. Furthermore, we show how this software can be systematically extended for more complex problems such as nonlinear absorption reconstruction for fluorescence-mediated tomography.
GPU-Accelerated Adjoint Algorithmic Differentiation
Gremse, Felix; Höfter, Andreas; Razik, Lukas; Kiessling, Fabian; Naumann, Uwe
2015-01-01
Many scientific problems such as classifier training or medical image reconstruction can be expressed as minimization of differentiable real-valued cost functions and solved with iterative gradient-based methods. Adjoint algorithmic differentiation (AAD) enables automated computation of gradients of such cost functions implemented as computer programs. To backpropagate adjoint derivatives, excessive memory is potentially required to store the intermediate partial derivatives on a dedicated data structure, referred to as the “tape”. Parallelization is difficult because threads need to synchronize their accesses during taping and backpropagation. This situation is aggravated for many-core architectures, such as Graphics Processing Units (GPUs), because of the large number of light-weight threads and the limited memory size in general as well as per thread. We show how these limitations can be mediated if the cost function is expressed using GPU-accelerated vector and matrix operations which are recognized as intrinsic functions by our AAD software. We compare this approach with naive and vectorized implementations for CPUs. We use four increasingly complex cost functions to evaluate the performance with respect to memory consumption and gradient computation times. Using vectorization, CPU and GPU memory consumption could be substantially reduced compared to the naive reference implementation, in some cases even by an order of complexity. The vectorization allowed usage of optimized parallel libraries during forward and reverse passes which resulted in high speedups for the vectorized CPU version compared to the naive reference implementation. The GPU version achieved an additional speedup of 7.5 ± 4.4, showing that the processing power of GPUs can be utilized for AAD using this concept. Furthermore, we show how this software can be systematically extended for more complex problems such as nonlinear absorption reconstruction for fluorescence-mediated tomography
Self-adjointness and conservation laws of difference equations
NASA Astrophysics Data System (ADS)
Peng, Linyu
2015-06-01
A general theorem on conservation laws for arbitrary difference equations is proved. The theorem is based on an introduction of an adjoint system related with a given difference system, and it does not require the existence of a difference Lagrangian. It is proved that the system, combined by the original system and its adjoint system, is governed by a variational principle, which inherits all symmetries of the original system. Noether's theorem can then be applied. With some special techniques, e.g. self-adjointness properties, this allows us to obtain conservation laws for difference equations, which are not necessary governed by Lagrangian formalisms.
Sensitivity of Lumped Constraints Using the Adjoint Method
NASA Technical Reports Server (NTRS)
Akgun, Mehmet A.; Haftka, Raphael T.; Wu, K. Chauncey; Walsh, Joanne L.
1999-01-01
Adjoint sensitivity calculation of stress, buckling and displacement constraints may be much less expensive than direct sensitivity calculation when the number of load cases is large. Adjoint stress and displacement sensitivities are available in the literature. Expressions for local buckling sensitivity of isotropic plate elements are derived in this study. Computational efficiency of the adjoint method is sensitive to the number of constraints and, therefore, the method benefits from constraint lumping. A continuum version of the Kreisselmeier-Steinhauser (KS) function is chosen to lump constraints. The adjoint and direct methods are compared for three examples: a truss structure, a simple HSCT wing model, and a large HSCT model. These sensitivity derivatives are then used in optimization.
Optimizing Spectral Wave Estimates with Adjoint-Based Sensitivity Maps
2014-02-18
forecasts of nearshore wave conditions are important to a diverse constituency, including vacation destinations such as Miami Beach or San Diego, coastal...a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 18 FEB 2014 2. REPORT TYPE 3. DATES...Sensitivity maps for wave spectra For any type of adjoint, sensitivity maps may be constructed from adjoint output to track the response of system properties
Observational consequences of the standard model Higgs inflation variants
Popa, L.A.
2011-10-01
We consider the possibility to observationally differentiate the Standard Model (SM) Higgs driven inflation with non-minimal coupling to gravity from other variants of SM Higgs inflation based on the scalar field theories with non-canonical kinetic term such as Galileon-like kinetic term and kinetic term with non-minimal derivative coupling to the Einstein tensor. In order to ensure consistent results, we study the SM Higgs inflation variants by using the same method, computing the full dynamics of the background and perturbations of the Higgs field during inflation at quantum level. Assuming that all the SM Higgs inflation variants are consistent theories, we use the MCMC technique to derive constraints on the inflationary parameters and the Higgs boson mass from their fit to WMAP7+SN+BAO data set. We conclude that a combination of the SM Higgs mass measurement by the LHC and accurate determination by the PLANCK satellite of the spectral index of curvature perturbations and tensor-to-scalar ratio will enable to distinguish among these models. We also show that the consistency relations of the SM Higgs inflation variants are distinct enough to differentiate among them.
Global adjoint tomography: First-generation model
Bozdag, Ebru; Peter, Daniel; Lefebvre, Matthieu; Komatitsch, Dimitri; Tromp, Jeroen; Hill, Judith C.; Podhorszki, Norbert; Pugmire, David
2016-09-22
We present the first-generation global tomographic model constructed based on adjoint tomography, an iterative full-waveform inversion technique. Synthetic seismograms were calculated using GPU-accelerated spectral-element simulations of global seismic wave propagation, accommodating effects due to 3-D anelastic crust & mantle structure, topography & bathymetry, the ocean load, ellipticity, rotation, and self-gravitation. Fréchet derivatives were calculated in 3-D anelastic models based on an adjoint-state method. The simulations were performed on the Cray XK7 named ‘Titan’, a computer with 18 688 GPU accelerators housed at Oak Ridge National Laboratory. The transversely isotropic global model is the result of 15 tomographic iterations, which systematically reduced differences between observed and simulated three-component seismograms. Our starting model combined 3-D mantle model S362ANI with 3-D crustal model Crust2.0. We simultaneously inverted for structure in the crust and mantle, thereby eliminating the need for widely used ‘crustal corrections’. We used data from 253 earthquakes in the magnitude range 5.8 ≤ M_{w} ≤ 7.0. We started inversions by combining ~30 s body-wave data with ~60 s surface-wave data. The shortest period of the surface waves was gradually decreased, and in the last three iterations we combined ~17 s body waves with ~45 s surface waves. We started using 180 min long seismograms after the 12th iteration and assimilated minor- and major-arc body and surface waves. The 15th iteration model features enhancements of well-known slabs, an enhanced image of the Samoa/Tahiti plume, as well as various other plumes and hotspots, such as Caroline, Galapagos, Yellowstone and Erebus. Furthermore, we see clear improvements in slab resolution along the Hellenic and Japan Arcs, as well as subduction along the East of Scotia Plate, which does not exist in the starting model. Point-spread function tests demonstrate that we are approaching
Global adjoint tomography: First-generation model
Bozdag, Ebru; Peter, Daniel; Lefebvre, Matthieu; ...
2016-09-22
We present the first-generation global tomographic model constructed based on adjoint tomography, an iterative full-waveform inversion technique. Synthetic seismograms were calculated using GPU-accelerated spectral-element simulations of global seismic wave propagation, accommodating effects due to 3-D anelastic crust & mantle structure, topography & bathymetry, the ocean load, ellipticity, rotation, and self-gravitation. Fréchet derivatives were calculated in 3-D anelastic models based on an adjoint-state method. The simulations were performed on the Cray XK7 named ‘Titan’, a computer with 18 688 GPU accelerators housed at Oak Ridge National Laboratory. The transversely isotropic global model is the result of 15 tomographic iterations, which systematicallymore » reduced differences between observed and simulated three-component seismograms. Our starting model combined 3-D mantle model S362ANI with 3-D crustal model Crust2.0. We simultaneously inverted for structure in the crust and mantle, thereby eliminating the need for widely used ‘crustal corrections’. We used data from 253 earthquakes in the magnitude range 5.8 ≤ Mw ≤ 7.0. We started inversions by combining ~30 s body-wave data with ~60 s surface-wave data. The shortest period of the surface waves was gradually decreased, and in the last three iterations we combined ~17 s body waves with ~45 s surface waves. We started using 180 min long seismograms after the 12th iteration and assimilated minor- and major-arc body and surface waves. The 15th iteration model features enhancements of well-known slabs, an enhanced image of the Samoa/Tahiti plume, as well as various other plumes and hotspots, such as Caroline, Galapagos, Yellowstone and Erebus. Furthermore, we see clear improvements in slab resolution along the Hellenic and Japan Arcs, as well as subduction along the East of Scotia Plate, which does not exist in the starting model. Point-spread function tests demonstrate that we are approaching
Global adjoint tomography: first-generation model
NASA Astrophysics Data System (ADS)
Bozdağ, Ebru; Peter, Daniel; Lefebvre, Matthieu; Komatitsch, Dimitri; Tromp, Jeroen; Hill, Judith; Podhorszki, Norbert; Pugmire, David
2016-12-01
We present the first-generation global tomographic model constructed based on adjoint tomography, an iterative full-waveform inversion technique. Synthetic seismograms were calculated using GPU-accelerated spectral-element simulations of global seismic wave propagation, accommodating effects due to 3-D anelastic crust & mantle structure, topography & bathymetry, the ocean load, ellipticity, rotation, and self-gravitation. Fréchet derivatives were calculated in 3-D anelastic models based on an adjoint-state method. The simulations were performed on the Cray XK7 named `Titan', a computer with 18 688 GPU accelerators housed at Oak Ridge National Laboratory. The transversely isotropic global model is the result of 15 tomographic iterations, which systematically reduced differences between observed and simulated three-component seismograms. Our starting model combined 3-D mantle model S362ANI with 3-D crustal model Crust2.0. We simultaneously inverted for structure in the crust and mantle, thereby eliminating the need for widely used `crustal corrections'. We used data from 253 earthquakes in the magnitude range 5.8 ≤ Mw ≤ 7.0. We started inversions by combining ˜30 s body-wave data with ˜60 s surface-wave data. The shortest period of the surface waves was gradually decreased, and in the last three iterations we combined ˜17 s body waves with ˜45 s surface waves. We started using 180 min long seismograms after the 12th iteration and assimilated minor- and major-arc body and surface waves. The 15th iteration model features enhancements of well-known slabs, an enhanced image of the Samoa/Tahiti plume, as well as various other plumes and hotspots, such as Caroline, Galapagos, Yellowstone and Erebus. Furthermore, we see clear improvements in slab resolution along the Hellenic and Japan Arcs, as well as subduction along the East of Scotia Plate, which does not exist in the starting model. Point-spread function tests demonstrate that we are approaching the resolution
Lincoln, Don
2016-12-14
The Higgs boson burst into the public arena on July 4, 2012, when scientists working at the CERN laboratory announced the particleâs discovery. However the initial discovery was a bit tentative, with the need to verify that the discovered particle was, indeed, the Higgs boson. In this video, Fermilabâs Dr. Don Lincoln looks at the data from the perspective of 2016 and shows that more recent analyses further supports the idea that the Higgs boson is what was discovered.
Adjoint operator approach in marginal separation theory
NASA Astrophysics Data System (ADS)
Braun, Stefan; Scheichl, Stefan; Kluwick, Alfred
2013-10-01
Thin airfoils are prone to localized flow separation at their leading edge if subjected to moderate angles of attack α. Although 'laminar separation bubbles' at first do not significantly alter the airfoil performance, they tend to 'burst' if a is increased further or perturbations acting upon the flow reach a certain intensity. This then leads either to global flow separation (stall) or triggers the laminar-turbulent transition process within the boundary layer flow. The present paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number Re → ∞, commonly referred to as marginal separation theory (MST). A new approach based on the adjoint operator method is presented to derive the fundamental similarity laws of MST and to extend the analysis to higher order. Special emphasis is placed on the breakdown of the flow description, i.e. the formation of finite time singularities (a manifestation of the bursting process), and its resolution based on asymptotic reasoning. The computation of the spatio-temporal evolution of the flow in the subsequent triple deck stage is performed by means of a Chebyshev spectral method. The associated numerical treatment of fractional integrals characteristic of MST is based on barycentric Lagrange interpolation, which is described in detail.
Adjoint estimation of ozone climate penalties
NASA Astrophysics Data System (ADS)
Zhao, Shunliu; Pappin, Amanda J.; Morteza Mesbah, S.; Joyce Zhang, J. Y.; MacDonald, Nicole L.; Hakami, Amir
2013-10-01
adjoint of a regional chemical transport model is used to calculate location-specific temperature influences (climate penalties) on two policy-relevant ozone metrics: concentrations in polluted regions (>65 ppb) and short-term mortality in Canada and the U.S. Temperature influences through changes in chemical reaction rates, atmospheric moisture content, and biogenic emissions exhibit significant spatial variability. In particular, high-NOx, polluted regions are prominently distinguished by substantial climate penalties (up to 6.2 ppb/K in major urban areas) as a result of large temperature influences through increased biogenic emissions and nonnegative water vapor sensitivities. Temperature influences on ozone mortality, when integrated across the domain, result in 369 excess deaths/K in Canada and the U.S. over a summer season—an impact comparable to a 5% change in anthropogenic NOx emissions. As such, we suggest that NOx control can be also regarded as a climate change adaptation strategy with regard to ozone air quality.
Adjoint methods for aerodynamic wing design
NASA Technical Reports Server (NTRS)
Grossman, Bernard
1993-01-01
A model inverse design problem is used to investigate the effect of flow discontinuities on the optimization process. The optimization involves finding the cross-sectional area distribution of a duct that produces velocities that closely match a targeted velocity distribution. Quasi-one-dimensional flow theory is used, and the target is chosen to have a shock wave in its distribution. The objective function which quantifies the difference between the targeted and calculated velocity distributions may become non-smooth due to the interaction between the shock and the discretization of the flowfield. This paper offers two techniques to resolve the resulting problems for the optimization algorithms. The first, shock-fitting, involves careful integration of the objective function through the shock wave. The second, coordinate straining with shock penalty, uses a coordinate transformation to align the calculated shock with the target and then adds a penalty proportional to the square of the distance between the shocks. The techniques are tested using several popular sensitivity and optimization methods, including finite-differences, and direct and adjoint discrete sensitivity methods. Two optimization strategies, Gauss-Newton and sequential quadratic programming (SQP), are used to drive the objective function to a minimum.
NASA Astrophysics Data System (ADS)
Bélusca-Maïto, Hermès; Falkowski, Adam; Fontes, Duarte; Romão, Jorge C.; Silva, João P.
2017-03-01
We discuss the validity of the Standard Model Effective Field Theory (SM EFT) as the low-energy effective theory for the two-Higgs-doublet Model (2HDM). Using the up-to-date Higgs signal strength measurements at the LHC, one can obtain a likelihood function for the Wilson coefficients of dimension-6 operators in the EFT Lagrangian. Given the matching between the 2HDM and the EFT, the constraints on the Wilson coefficients can be translated into constraints on the parameters of the 2HDM Lagrangian. We discuss under which conditions such a procedure correctly reproduces the true limits on the 2HDM. Finally, we employ the SM EFT to identify the pattern of the Higgs boson couplings that are needed to improve the fit to the current Higgs data. To this end, one needs, simultaneously, to increase the top Yukawa coupling, decrease the bottom Yukawa coupling, and induce a new contact interaction of the Higgs boson with gluons. We comment on how these modifications can be realized in the 2HDM extended by new colored particles.
Higgs vacuum stability and modified chaotic inflation
NASA Astrophysics Data System (ADS)
Saha, Abhijit Kumar; Sil, Arunansu
2017-02-01
The issue of electroweak vacuum stability is studied in presence of a scalar field which participates in modifying the minimal chaotic inflation model. It is shown that the threshold effect on the Higgs quartic coupling originating from the Higgs-inflaton sector interaction can essentially make the electroweak vacuum stable up to the Planck scale. On the other hand we observe that the new physics parameters in this combined framework are enough to provide deviation from the minimal chaotic inflation predictions so as to keep it consistent with recent observation by Planck 2015.
Dimension-six triple gluon operator in Higgs +jet observables
NASA Astrophysics Data System (ADS)
Ghosh, Diptimoy; Wiebusch, Martin
2015-02-01
Recently a lot of progress has been made towards a full classification of new physics effects in Higgs observables by means of effective dimension-six operators. Specifically, Higgs production in association with a high transverse momentum jet has been suggested as a way to discriminate between operators that modify the Higgs-top coupling (Ot) and operators that induce an effective Higgs-gluon coupling (Og)—a distinction that is hard to achieve with signal strength measurements alone. With this article we would like to draw attention to another source of new physics in Higgs +jet observables: the triple gluon operator O3 g (consisting of three factors of the gluon field strength tensor). We compute the distortions of kinematic distributions in Higgs +jet production at a 14 TeV LHC due to O3 g and compare them with the distortions due to Ot and Og. We find that the transverse momentum distributions alone cannot discriminate between O3 g and Og if the coefficient of the operator Ot treated as an unknown parameter. We further show that the jet rapidity and the difference between the Higgs and jet rapidity are well suited to remove this new degeneracy. Using rough estimates for the expected bounds we find that allowed distortions in kinematic distributions due to Og are of similar size as those due to O3 g. We conclude that a full analysis of new physics in Higgs +jet observables must take the contributions from O3 g into account.
Holographic dark matter and Higgs models.
Díaz-Cruz, J Lorenzo
2008-06-06
We propose a dark matter candidate within the class of models where electroweak symmetry breaking is triggered by a light composite Higgs boson. In these dual anti-de Sitter/conformal field theory models, the Higgs boson emerges as a holographic pseudo-Goldstone boson, while dark matter can be identified with a stable composite fermion X0. The effective Lagrangian description of the Higgs and X0-multiplets, including higher-dimensional operators, can be tested at future colliders (LHC, ILC) and through astrophysical signals (ultrahigh-energy cosmic rays). The expected mass of X0, mX0 < or approximately 4pif approximately O (TeV), satisfies the bounds extracted from the cosmological relic density, while the experimental searches for dark matter further constrains the possible models.
Neutrino Oscillations, the Higgs Boson, and the Private Higgs Model
NASA Astrophysics Data System (ADS)
BenTov, Jonathan
"CESR, PEP, PETRA, ISABELLE, p-bar p colliders, LEP, the tevatron, and ep machines are at various levels of design or construction. They will study the properties of b-matter, see weak intermediaries, and perhaps find the t-quark and the Higgs boson. Never before was there such a bestiary waiting to be discovered; and what surprises will be found!" - S. L. Glashow ("The Future of Elementary Particle Physics," Quarks and Leptons, NATO Advanced Study Institutes Series Volume 61, 1980, pp 687-713) The situation in 1980 was clearly different from the present situation in 2013, in which we face the very real possibilty that no new degrees of freedom will ever again be within reach of a collider. In an intriguing twist of fate, this very fact results in a sharp paradox for fundamental physics: the Higgs mass should be MP/m h ˜ 1017 times larger than it actually is, and the vacuum energy density of the universe should be (M P/A)4 ˜ (1031)4 times larger than it actually is, and apparently nature refuses to give us any more clues as to why. These together are what I would call the main problem of 21st century physics: despite all of the predictive success of particle physics so far, we must find a way to suitably modify the rules of quantum field theory, lest we accept the unproductive defeatist attitude that our universe is simply fine-tuned. In the meantime, there is much interesting work to be done in more "traditional" particle physics: we have learned that neutrinos actually have tiny but nonzero masses, which is clear and unambiguous evidence for physics beyond the Standard Model. I will allocate the first third of this document to phenomena related to neutrino oscillations. In particular, I would like to argue that some of the apparent differences between neutrino mixing and quark mixing are to an extent illusory, and actually many aspects of the two sectors can be understood in a coherent framework for extending the Standard Model. The remaining two-thirds of this
NASA Astrophysics Data System (ADS)
Brivio, I.; Éboli, O. J. P.; Gavela, M. B.; Gonzalez-García, M. C.; Merlo, L.; Rigolin, S.
2014-12-01
We analyze the leading effective operators which induce a quartic momentum dependence in the Higgs propagator, for a linear and for a non-linear realization of electroweak symmetry breaking. Their specific study is relevant for the understanding of the ultraviolet sensitivity to new physics. Two methods of analysis are applied, trading the Lagrangian coupling by: i) a "ghost" scalar, after the Lee-Wick procedure; ii) other effective operators via the equations of motion. The two paths are shown to lead to the same effective Lagrangian at first order in the operator coefficients. It follows a modification of the Higgs potential and of the fermionic couplings in the linear realization, while in the non-linear one anomalous quartic gauge couplings, Higgs-gauge couplings and gauge-fermion interactions are induced in addition. Finally, all LHC Higgs and other data presently available are used to constrain the operator coefficients; the future impact of pp → 4 leptons data via off-shell Higgs exchange and of vector boson fusion data is considered as well. For completeness, a summary of pure-gauge and gauge-Higgs signals exclusive to non-linear dynamics at leading-order is included.
Adjoint-Based Methodology for Time-Dependent Optimization
NASA Technical Reports Server (NTRS)
Yamaleev, N. K.; Diskin, B.; Nielsen, E. J.
2008-01-01
This paper presents a discrete adjoint method for a broad class of time-dependent optimization problems. The time-dependent adjoint equations are derived in terms of the discrete residual of an arbitrary finite volume scheme which approximates unsteady conservation law equations. Although only the 2-D unsteady Euler equations are considered in the present analysis, this time-dependent adjoint method is applicable to the 3-D unsteady Reynolds-averaged Navier-Stokes equations with minor modifications. The discrete adjoint operators involving the derivatives of the discrete residual and the cost functional with respect to the flow variables are computed using a complex-variable approach, which provides discrete consistency and drastically reduces the implementation and debugging cycle. The implementation of the time-dependent adjoint method is validated by comparing the sensitivity derivative with that obtained by forward mode differentiation. Our numerical results show that O(10) optimization iterations of the steepest descent method are needed to reduce the objective functional by 3-6 orders of magnitude for test problems considered.
Optimization of wind plant layouts using an adjoint approach
King, Ryan N.; Dykes, Katherine; Graf, Peter; ...
2017-03-10
Using adjoint optimization and three-dimensional steady-state Reynolds-averaged Navier–Stokes (RANS) simulations, we present a new gradient-based approach for optimally siting wind turbines within utility-scale wind plants. By solving the adjoint equations of the flow model, the gradients needed for optimization are found at a cost that is independent of the number of control variables, thereby permitting optimization of large wind plants with many turbine locations. Moreover, compared to the common approach of superimposing prescribed wake deficits onto linearized flow models, the computational efficiency of the adjoint approach allows the use of higher-fidelity RANS flow models which can capture nonlinear turbulent flowmore » physics within a wind plant. The steady-state RANS flow model is implemented in the Python finite-element package FEniCS and the derivation and solution of the discrete adjoint equations are automated within the dolfin-adjoint framework. Gradient-based optimization of wind turbine locations is demonstrated for idealized test cases that reveal new optimization heuristics such as rotational symmetry, local speedups, and nonlinear wake curvature effects. Layout optimization is also demonstrated on more complex wind rose shapes, including a full annual energy production (AEP) layout optimization over 36 inflow directions and 5 wind speed bins.« less
Mesh-free adjoint methods for nonlinear filters
NASA Astrophysics Data System (ADS)
Daum, Fred
2005-09-01
We apply a new industrial strength numerical approximation, called the "mesh-free adjoint method", to solve the nonlinear filtering problem. This algorithm exploits the smoothness of the problem, unlike particle filters, and hence we expect that mesh-free adjoints are superior to particle filters for many practical applications. The nonlinear filter problem is equivalent to solving the Fokker-Planck equation in real time. The key idea is to use a good adaptive non-uniform quantization of state space to approximate the solution of the Fokker-Planck equation. In particular, the adjoint method computes the location of the nodes in state space to minimize errors in the final answer. This use of an adjoint is analogous to optimal control algorithms, but it is more interesting. The adjoint method is also analogous to importance sampling in particle filters, but it is better for four reasons: (1) it exploits the smoothness of the problem; (2) it explicitly minimizes the errors in the relevant functional; (3) it explicitly models the dynamics in state space; and (4) it can be used to compute a corrected value for the desired functional using the residuals. We will attempt to make this paper accessible to normal engineers who do not have PDEs for breakfast.
Adjoint simulation of stream depletion due to aquifer pumping.
Neupauer, Roseanna M; Griebling, Scott A
2012-01-01
If an aquifer is hydraulically connected to an adjacent stream, a pumping well operating in the aquifer will draw some water from aquifer storage and some water from the stream, causing stream depletion. Several analytical, semi-analytical, and numerical approaches have been developed to estimate stream depletion due to pumping. These approaches are effective if the well location is known. If a new well is to be installed, it may be desirable to install the well at a location where stream depletion is minimal. If several possible locations are considered for the location of a new well, stream depletion would have to be estimated for all possible well locations, which can be computationally inefficient. The adjoint approach for estimating stream depletion is a more efficient alternative because with one simulation of the adjoint model, stream depletion can be estimated for pumping at a well at any location. We derive the adjoint equations for a coupled system with a confined aquifer, an overlying unconfined aquifer, and a river that is hydraulically connected to the unconfined aquifer. We assume that the stage in the river is known, and is independent of the stream depletion, consistent with the assumptions of the MODFLOW river package. We describe how the adjoint equations can be solved using MODFLOW. In an illustrative example, we show that for this scenario, the adjoint approach is as accurate as standard forward numerical simulation methods, and requires substantially less computational effort.
NASA Astrophysics Data System (ADS)
Tang, T.; Boroumand, A.; Abriola, L. M.; Miller, E. L.
2013-12-01
Characterization of dense non-aqueous phase liquid (DNAPL) source zones is a critical component for successful remediation of sites contaminated by chlorinated solvents. Although Push-Pull Tracer Tests (PPTTs) offer a promising approach for local in situ source zone characterization, non-equilibrium mass transfer effects and the spatial variability of saturation make their interpretation difficult. To better understand the dependence of well test data on these factors and as the basis for the estimation of the spatial DNAPL distribution, here we develop numerical methods based on the use of adjoint sensitivity mehtods to explore the sensitivity of PPTT observations to the distribution of DNAPL saturation. We examine the utility of the developed approach using three-dimensional hypothetical source zones containing heterogeneous DNAPL distributions. For model applications the flow fields are generated with MODFLOW and non-equilibrium tracer mass transfer is described by a linear driving force expression. Comprehensive modeling of partitioning tracer tests requires the solution of tracer mass balance equations in the aqueous and DNAPL phases. Consistent with this process coupling, the developed adjoint method introduces a vector of adjoint variables to formulate the coupled adjoint states equations for tracer concentrations in both the aqueous and NAPL phases. For the sensitivity analysis, we investigate how the tracer concentration in the well changes with perturbations of the saturation within the interrogated zone. Using the calculated sensitivity functions, coupled with the observed tracer breakthrough curve, we develop a nonlinear least-squares inverse method to determine three metrics related to the spatial distribution of DNAPL in the source zone: average DNAPL saturation, total mass of DNAPL and distance of the DNAPL from the test well. These results have utility for local source zone characterization and can provide an initial quantitative understanding of
Tomography, Adjoint Methods, Time-Reversal, and Banana-Doughnut Kernels
NASA Astrophysics Data System (ADS)
Tape, C.; Tromp, J.; Liu, Q.
2004-12-01
We demonstrate that Fréchet derivatives for tomographic inversions may be obtained based upon just two calculations for each earthquake: one calculation for the current model and a second, `adjoint', calculation that uses time-reversed signals at the receivers as simultaneous, fictitious sources. For a given model~m, we consider objective functions χ(m) that minimize differences between waveforms, traveltimes, or amplitudes. We show that the Fréchet derivatives of such objective functions may be written in the generic form δ χ=∫ VK_m( {x}) δ ln m( {x}) d3 {x}, where δ ln m=δ m/m denotes the relative model perturbation. The volumetric kernel Km is defined throughout the model volume V and is determined by time-integrated products between spatial and temporal derivatives of the regular displacement field {s} and the adjoint displacement field {s} obtained by using time-reversed signals at the receivers as simultaneous sources. In waveform tomography the time-reversed signal consists of differences between the data and the synthetics, in traveltime tomography it is determined by synthetic velocities, and in amplitude tomography it is controlled by synthetic displacements. For each event, the construction of the kernel Km requires one forward calculation for the regular field {s} and one adjoint calculation involving the fields {s} and {s}. For multiple events the kernels are simply summed. The final summed kernel is controlled by the distribution of events and stations and thus determines image resolution. In the case of traveltime tomography, the kernels Km are weighted combinations of banana-doughnut kernels. We demonstrate also how amplitude anomalies may be inverted for lateral variations in elastic and anelastic structure. The theory is illustrated based upon 2D spectral-element simulations.
Working Group Report: Higgs Boson
Dawson, Sally; Gritsan, Andrei; Logan, Heather; Qian, Jianming; Tully, Chris; Van Kooten, Rick
2013-10-30
This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).
A ball pool model to illustrate Higgs physics to the public
NASA Astrophysics Data System (ADS)
Organtini, Giovanni
2017-03-01
A simple model is presented to explain Higgs boson physics to the grand public. The model consists of a children’s ball pool representing a Universe filled with a certain amount of the Higgs field. The model is suitable for usage as a hands-on tool in scientific exhibits and provides a clear explanation of almost all the aspects of the physics of the Higgs field interaction with other particles.
Time-resolved study of Higgs mode in superconductors
NASA Astrophysics Data System (ADS)
Shimano, Ryo
The behavior of superconductors far from equilibrium has been intensively studied over decades. Goals of these studies are the elucidation of bosonic fluctuations essential for the pairing mechanisms, the manifestation of competing orders or hidden phases, and the optical manipulation of superconductivity. The study of collective modes is crucially important for these perspectives as it provides the information on the dynamics of order parameters in non-equilibirium states. Generally, collective modes in ordered phases associated with spontaneous symmetry breaking are classified into 1) gapless phase modes and 2) gapped amplitude modes. In superconductors, the phase mode is eaten by gauge field, according to the Anderson-Higgs mechanism. The remaining amplitude mode is recently termed as Higgs mode from its analogy to the Higgs boson in particle physics. Despite its long history of investigation, unambiguous observation of Higgs mode has remained elusive. This is because the Higgs mode does not have a charge nor electric dipole and therefore it does not couple directly to the electromagnetic field. Here we report on our recent observation of Higgs mode in s-wave superconductors by using THz-pump and THz-probe spectroscopy technique. After nonadiabatic excitation near the superconducting gap energy with monocycle THz pulses, Higgs mode was observed as oscillations in the transmission of THz probe pulse. The resonant nonlinear coupling between the Higgs mode and coherent radiation field was also discovered, resulting in an efficient third order harmonic generation of the incident THz radiation. The extension of experiments to multiband superconductors and unconventional superconductors will be discussed. Time-resolved study of Higgs mode in superconductors.
Higgs-stoponium mixing near the stop-antistop threshold
NASA Astrophysics Data System (ADS)
Bodwin, Geoffrey T.; Chung, Hee Sok; Wagner, Carlos E. M.
2017-01-01
Supersymmetric extensions of the standard model contain additional heavy neutral Higgs bosons that are coupled to heavy scalar top quarks (stops). This system exhibits interesting field theoretic phenomena when the Higgs mass is close to the stop-antistop production threshold. Existing work in the literature has examined the digluon-to-diphoton cross section near threshold and has focused on enhancements in the cross section that might arise either from the perturbative contributions to the Higgs-to-digluon and Higgs-to-diphoton form factors or from mixing of the Higgs boson with stoponium states. Near threshold, enhancements in the relevant amplitudes that go as inverse powers of the stop-antistop relative velocity require resummations of perturbation theory and/or nonperturbative treatments. We present a complete formulation of threshold effects at leading order in the stop-antistop relative velocity in terms of nonrelativistic effective field theory. We give detailed numerical calculations for the case in which the stop-antistop Green's function is modeled with a Coulomb-Schrödinger Green's function. We find several general effects that do not appear in a purely perturbative treatment. Higgs-stop-antistop mixing effects displace physical masses from the threshold region, thereby rendering the perturbative threshold enhancements inoperative. In the case of large Higgs-stop-antistop couplings, the displacement of a physical state above threshold substantially increases its width, owing to its decay width to a stop-antistop pair, and greatly reduces its contribution to the cross section.
Sonic Boom Mitigation Through Aircraft Design and Adjoint Methodology
NASA Technical Reports Server (NTRS)
Rallabhandi, Siriam K.; Diskin, Boris; Nielsen, Eric J.
2012-01-01
This paper presents a novel approach to design of the supersonic aircraft outer mold line (OML) by optimizing the A-weighted loudness of sonic boom signature predicted on the ground. The optimization process uses the sensitivity information obtained by coupling the discrete adjoint formulations for the augmented Burgers Equation and Computational Fluid Dynamics (CFD) equations. This coupled formulation links the loudness of the ground boom signature to the aircraft geometry thus allowing efficient shape optimization for the purpose of minimizing the impact of loudness. The accuracy of the adjoint-based sensitivities is verified against sensitivities obtained using an independent complex-variable approach. The adjoint based optimization methodology is applied to a configuration previously optimized using alternative state of the art optimization methods and produces additional loudness reduction. The results of the optimizations are reported and discussed.
A Posteriori Analysis for Hydrodynamic Simulations Using Adjoint Methodologies
Woodward, C S; Estep, D; Sandelin, J; Wang, H
2009-02-26
This report contains results of analysis done during an FY08 feasibility study investigating the use of adjoint methodologies for a posteriori error estimation for hydrodynamics simulations. We developed an approach to adjoint analysis for these systems through use of modified equations and viscosity solutions. Targeting first the 1D Burgers equation, we include a verification of the adjoint operator for the modified equation for the Lax-Friedrichs scheme, then derivations of an a posteriori error analysis for a finite difference scheme and a discontinuous Galerkin scheme applied to this problem. We include some numerical results showing the use of the error estimate. Lastly, we develop a computable a posteriori error estimate for the MAC scheme applied to stationary Navier-Stokes.
Higgs searches at the Tevatron
Qizhong Li
2003-06-10
One of the highest priority physics goals for the upgraded Tevatron experiments, CDF and D0, is the search for the Higgs boson. We present the initial results from both experiments, based on 40-90 pb{sup -1} integrated luminosity, of Higgs searches in several final states, including WH and ZH, H {yields} WW, and doubly-charged Higgs.
Determining triple gauge boson couplings from Higgs data.
Corbett, Tyler; Éboli, O J P; Gonzalez-Fraile, J; Gonzalez-Garcia, M C
2013-07-05
In the framework of effective Lagrangians with the SU(2)(L)×U(1)(Y) symmetry linearly realized, modifications of the couplings of the Higgs field to the electroweak gauge bosons are related to anomalous triple gauge couplings (TGCs). Here, we show that the analysis of the latest Higgs boson production data at the LHC and Tevatron give rise to strong bounds on TGCs that are complementary to those from direct TGC analysis. We present the constraints on TGCs obtained by combining all available data on direct TGC studies and on Higgs production analysis.
Higgs-inflaton coupling from reheating and the metastable Universe
NASA Astrophysics Data System (ADS)
Gross, Christian; Lebedev, Oleg; Zatta, Marco
2016-02-01
Current Higgs boson and top quark data favor metastability of our vacuum which raises questions as to why the Universe has chosen an energetically disfavored state and remained there during inflation. In this Letter, we point out that these problems can be solved by a Higgs-inflaton coupling which appears in realistic models of inflation. Since an inflaton must couple to the Standard Model particles either directly or indirectly, such a coupling is generated radiatively, even if absent at tree level. As a result, the dynamics of the Higgs field can change dramatically.
Supersymmetric Sneutrino-Higgs inflation
NASA Astrophysics Data System (ADS)
Deen, Rehan; Ovrut, Burt A.; Purves, Austin
2016-11-01
It is shown that in the phenomenologically realistic supersymmetric B - L MSSM theory, a linear combination of the neutral, up Higgs field with the third family left- and right-handed sneutrinos can play the role of the cosmological inflaton. Assuming that supersymmetry is softly broken at a mass scale of order 1013 GeV, the potential energy associated with this field allows for 60 e-foldings of inflation with the cosmological parameters being consistent with all Planck2015 data. The theory does not require any non-standard coupling to gravity and the physical fields are all sub-Planckian during the inflationary epoch. It will be shown that there is a "robust" set of initial conditions which, in addition to satisfying the Planck data, simultaneously are consistent with all present LHC phenomenological requirements.
Adjoint-based optimization of fish swimming gaits
NASA Astrophysics Data System (ADS)
Floryan, Daniel; Rowley, Clarence W.; Smits, Alexander J.
2016-11-01
We study a simplified model of fish swimming, namely a flat plate periodically pitching about its leading edge. Using gradient-based optimization, we seek periodic gaits that are optimal in regards to a particular objective (e.g. maximal thrust). The two-dimensional immersed boundary projection method is used to investigate the flow states, and its adjoint formulation is used to efficiently calculate the gradient of the objective function needed for optimization. The adjoint method also provides sensitivity information, which may be used to elucidate the physics responsible for optimality. Supported under ONR MURI Grants N00014-14-1-0533, Program Manager Bob Brizzolara.
Supersonic biplane design via adjoint method
NASA Astrophysics Data System (ADS)
Hu, Rui
In developing the next generation supersonic transport airplane, two major challenges must be resolved. The fuel efficiency must be significantly improved, and the sonic boom propagating to the ground must be dramatically reduced. Both of these objectives can be achieved by reducing the shockwaves formed in supersonic flight. The Busemann biplane is famous for using favorable shockwave interaction to achieve nearly shock-free supersonic flight at its design Mach number. Its performance at off-design Mach numbers, however, can be very poor. This dissertation studies the performance of supersonic biplane airfoils at design and off-design conditions. The choked flow and flow-hysteresis phenomena of these biplanes are studied. These effects are due to finite thickness of the airfoils and non-uniqueness of the solution to the Euler equations, creating over an order of magnitude more wave drag than that predicted by supersonic thin airfoil theory. As a result, the off-design performance is the major barrier to the practical use of supersonic biplanes. The main contribution of this work is to drastically improve the off-design performance of supersonic biplanes by using an adjoint based aerodynamic optimization technique. The Busemann biplane is used as the baseline design, and its shape is altered to achieve optimal wave drags in series of Mach numbers ranging from 1.1 to 1.7, during both acceleration and deceleration conditions. The optimized biplane airfoils dramatically reduces the effects of the choked flow and flow-hysteresis phenomena, while maintaining a certain degree of favorable shockwave interaction effects at the design Mach number. Compared to a diamond shaped single airfoil of the same total thickness, the wave drag of our optimized biplane is lower at almost all Mach numbers, and is significantly lower at the design Mach number. In addition, by performing a Navier-Stokes solution for the optimized airfoil, it is verified that the optimized biplane improves
Nonuniversal gaugino masses and seminatural supersymmetry in view of the Higgs boson discovery
Martin, Stephen P.
2014-02-20
I consider models with non-universal gaugino masses at the gauge coupling unification scale, taking into account the Higgs boson discovery. Viable regions of parameter space are mapped and studied in the case of non-universality following from an F-term in a linear combination of singlet and adjoint representations of SU(5). I consider, in particular, "semi-natural" models that have small \\mu, with gaugino masses dominating the supersymmetry breaking terms at high energies. Higgsino-like particles are then much lighter than all other superpartners, and the prospects for discovery at the Large Hadron Collider can be extremely challenging.
Living beyond the edge: Higgs inflation and vacuum metastability
Bezrukov, Fedor; Rubio, Javier; Shaposhnikov, Mikhail
2015-10-13
The measurements of the Higgs mass and top Yukawa coupling indicate that we live in a very special universe, at the edge of the absolute stability of the electroweak vacuum. If fully stable, the Standard Model (SM) can be extended all the way up to the inflationary scale and the Higgs field, nonminimally coupled to gravity with strength ξ, can be responsible for inflation. We show that the successful Higgs inflation scenario can also take place if the SM vacuum is not absolutely stable. This conclusion is based on two effects that were overlooked previously. The first one is associated with the effective renormalization of the SM couplings at the energy scale M_{P}/ξ, where M_{P} is the Planck scale. Lastly, the second one is a symmetry restoration after inflation due to high temperature effects that leads to the (temporary) disappearance of the vacuum at Planck values of the Higgs field.
Living beyond the edge: Higgs inflation and vacuum metastability
Bezrukov, Fedor; Rubio, Javier; Shaposhnikov, Mikhail
2015-10-13
The measurements of the Higgs mass and top Yukawa coupling indicate that we live in a very special universe, at the edge of the absolute stability of the electroweak vacuum. If fully stable, the Standard Model (SM) can be extended all the way up to the inflationary scale and the Higgs field, nonminimally coupled to gravity with strength ξ, can be responsible for inflation. We show that the successful Higgs inflation scenario can also take place if the SM vacuum is not absolutely stable. This conclusion is based on two effects that were overlooked previously. The first one is associatedmore » with the effective renormalization of the SM couplings at the energy scale MP/ξ, where MP is the Planck scale. Lastly, the second one is a symmetry restoration after inflation due to high temperature effects that leads to the (temporary) disappearance of the vacuum at Planck values of the Higgs field.« less
Harnik, Roni
2004-10-27
Supersymmetric models have traditionally been assumed to be perturbative up to high scales due to the requirement of calculable unification. In this note I review the recently proposed `Fat Higgs' model which relaxes the requirement of perturbativity. In this framework, an NMSSM-like trilinear coupling becomes strong at some intermediate scale. The NMSSM Higgses are meson composites of an asymptotically-free gauge theory. This allows us to raise the mass of the Higgs, thus alleviating the MSSM of its fine tuning problem. Despite the strong coupling at an intermediate scale, the UV completion allows us to maintain gauge coupling unification.
Adjoint-based minimization of the sound radiated by a Mach 1.3 turbulent jet
NASA Astrophysics Data System (ADS)
Kim, Jeonglae; Bodony, Daniel; Freund, Jonathan
2010-11-01
A control optimization using the adjoint of the perturbed and linearized Navier--Stokes equations is applied to a simulation of a Mach 1.3 turbulent jet to reduce its radiated sound. The solution of the adjoint system provides gradient information for a minimization algorithm to circumvent the flow complexity and reduce the sound directly. Comparisons between the loud and the perturbed-but-quiet versions of the same jet are examined to identify sound mechanisms. The overall algorithm is designed such that the control can be optimized with degrees of freedom comparable to that of the numerical discretization or with constraints on its spatial or temporal profiles to reflect hardware limitations. The large-eddy simulation of the uncontrolled, baseline jet is carried out in curvilinear coordinates using a non-dissipative high-order finite-difference. The far-field sound is computed using a Ffowcs Williams and Hawkings surface. Turbulence and far-field sound statistics agree with experimental data. An unconstrained optimal control reduces the sound cost functional by 17%. The far-field sound is reduced at all angles with a maximum reduction of 2.7dB in the peak radiation direction. Constraining the control in actuator-like zones shows a similar result. Optimizations are ongoing.
Kasamatsu, Kenichi; Ichinose, Ikuo; Matsui, Tetsuo
2013-09-13
Recently, the possibility of quantum simulation of dynamical gauge fields was pointed out by using a system of cold atoms trapped on each link in an optical lattice. However, to implement exact local gauge invariance, fine-tuning the interaction parameters among atoms is necessary. In the present Letter, we study the effect of violation of the U(1) local gauge invariance by relaxing the fine-tuning of the parameters and showing that a wide variety of cold atoms is still a faithful quantum simulator for a U(1) gauge-Higgs model containing a Higgs field sitting on sites. The clarification of the dynamics of this gauge-Higgs model sheds some light upon various unsolved problems, including the inflation process of the early Universe. We study the phase structure of this model by Monte Carlo simulation and also discuss the atomic characteristics of the Higgs phase in each simulator.
Adjoint Methods for Guiding Adaptive Mesh Refinement in Tsunami Modeling
NASA Astrophysics Data System (ADS)
Davis, B. N.; LeVeque, R. J.
2016-12-01
One difficulty in developing numerical methods for tsunami modeling is the fact that solutions contain time-varying regions where much higher resolution is required than elsewhere in the domain, particularly when tracking a tsunami propagating across the ocean. The open source GeoClaw software deals with this issue by using block-structured adaptive mesh refinement to selectively refine around propagating waves. For problems where only a target area of the total solution is of interest (e.g., one coastal community), a method that allows identifying and refining the grid only in regions that influence this target area would significantly reduce the computational cost of finding a solution. In this work, we show that solving the time-dependent adjoint equation and using a suitable inner product with the forward solution allows more precise refinement of the relevant waves. We present the adjoint methodology first in one space dimension for illustration and in a broad context since it could also be used in other adaptive software, and potentially for other tsunami applications beyond adaptive refinement. We then show how this adjoint method has been integrated into the adaptive mesh refinement strategy of the open source GeoClaw software and present tsunami modeling results showing that the accuracy of the solution is maintained and the computational time required is significantly reduced through the integration of the adjoint method into adaptive mesh refinement.
Assimilating Remote Ammonia Observations with a Refined Aerosol Thermodynamics Adjoint"
Ammonia emissions parameters in North America can be refined in order to improve the evaluation of modeled concentrations against observations. Here, we seek to do so by developing and applying the GEOS-Chem adjoint nested over North America to conductassimilation of observations...
Self-adjoint commuting differential operators of rank two
NASA Astrophysics Data System (ADS)
Mironov, A. E.
2016-08-01
This is a survey of results on self-adjoint commuting ordinary differential operators of rank two. In particular, the action of automorphisms of the first Weyl algebra on the set of commuting differential operators with polynomial coefficients is discussed, as well as the problem of constructing algebro-geometric solutions of rank l>1 of soliton equations. Bibliography: 59 titles.
NASA Astrophysics Data System (ADS)
Falkowski, A.; Grojean, C.; Kamińska, A.; Pokorski, S.; Weiler, A.
2011-11-01
In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions of parameter space where a minimal addition — a single spin-1 SU(2)custodial-triplet resonance — allows one to retain perturbative control in all channels. Elastic scattering of longitudinal W and Z bosons alone seems to permit a very large cut-off beyond the Naive Dimensional Analysis expectation. We find however that including scattering of the spin-1 resonances then leads to an earlier onset of strong coupling. Most importantly for LHC searches, we define a self-consistent set-up with a well-defined range of validity without recourse to unitarization schemes whose physical meaning is obscure. We discuss the LHC phenomenology and the discovery reach for these electroweak resonances and mention the possibility of a nightmare scenario with no Higgs nor resonance within the LHC reach. Finally, we discuss the effects of parity breaking in the heavy resonance sector which reduces the contributions to the S parameter.
Searching for composite Higgs models at the LHC
NASA Astrophysics Data System (ADS)
Flacke, Thomas
2016-07-01
Composite Higgs models have the potential to provide a solution to the hierarchy problem and a dynamical explanation for the generation of the Higgs potential. They can be tested at the LHC as the new sector which underlies electroweak symmetry breaking must become strong in the TeV regime, which implies additional bound states beyond the Higgs. In this paper, we first discuss prospects and search strategies for top partners (and other quark partners) in the strongly coupled sector, which we study in an effective field theory setup. In the second part of the proceedings, we go beyond the effective field theory approach. We discuss potential UV embeddings for composite Higgs models which contain a Higgs as well as top partners. We show that in all of these models, additional pseudo-Nambu-Goldstone bosons beyond the Higgs are present. In particular, all of the models contain a pseudoscalar which couples to the Standard Model gauge fields through Wess-Zumino-Witten terms, providing a prime candidate for a di-boson (including a di-photon) resonance. The models also contain colored pNGBs which can be searched for at the LHC.
Searching for Composite Higgs Models at the LHC
NASA Astrophysics Data System (ADS)
Flacke, Thomas
Composite Higgs models have the potential to provide a solution to the hierarchy problem and a dynamical explanation for the generation of the Higgs potential. They can be tested at the LHC as the new sector which underlies electroweak symmetry breaking must become strong in the TeV regime, which implies additional bound states beyond the Higgs. In this paper, we first discuss prospects and search strategies for top partners (and other quark partners) in the strongly coupled sector, which we study in an effective field theory setup. In the second part of the proceedings, we go beyond the effective field theory approach. We discuss potential UV embeddings for composite Higgs models which contain a Higgs as well as top partners. We show that in all of these models, additional pseudo-Nambu-Goldstone bosons beyond the Higgs are present. In particular, all of the models contain a pseudoscalar which couples to the Standard Model gauge fields through Wess-Zumino-Witten terms, providing a prime candidate for a di-boson (including a di-photon) resonance. The models also contain colored pNGBs which can be searched for at the LHC.
Bulk Higgs with a heavy diphoton signal
NASA Astrophysics Data System (ADS)
Frank, Mariana; Pourtolami, Nima; Toharia, Manuel
2017-02-01
We consider scenarios of warped extra dimensions with all matter fields in the bulk and in which both the hierarchy and the flavor puzzles of the Standard Model are addressed. Inspired by the puzzling excess of diphoton events at 750 GeV reported in the early LHC Run II data (since then understood as a statistical excess), we consider here the general question as to whether the simplest extra-dimensional extension of the Standard Model Higgs sector, i.e., a five-dimensional bulk Higgs doublet, can lead to an intermediate mass resonance (between 500 GeV and 1.5 TeV) of which the first signature would be the presence of diphoton events. This surprising phenomenology can happen if the resonance is the lightest C P -odd state coming from the Higgs sector. No new matter content is required, the only new ingredient being the presence of (positive) brane localized kinetic terms associated to the five-dimensional bulk Higgs (which reduce the mass of the C P -odd states). Production and decay of this resonance can naturally give rise to observable diphoton signals, keeping dijet production under control, with very low ZZ and WW signals and with a highly reduced top pair production in an important region of parameter space. We use the 750 GeV excess as an example case scenario.
Learning from a Higgs-like scalar resonance
NASA Astrophysics Data System (ADS)
Bauer, Martin; Butter, Anja; Gonzalez-Fraile, J.; Plehn, Tilman; Rauch, Michael
2017-03-01
Motivated by a diphoton anomaly observed by ATLAS and CMS we develop an SFitter analysis for a combined electroweak-Higgs sector, and a scalar portal at the LHC. The theoretical description is based on the linear effective Lagrangian for the Higgs and gauge fields, combined with an additional singlet scalar. The key target is the extraction of reliable information on the portal structure of the combined scalar potential. For the specific diphoton anomaly we find that the new state might well form such a Higgs portal. To obtain more conclusive results we define and test the connection of the Wilson coefficients in the Higgs and heavy scalar sectors, as suggested by a portal setup.
Bounce inflation cosmology with Standard Model Higgs boson
Wan, Youping; Huang, Fa Peng; Zhang, Xinmin; Qiu, Taotao; Cai, Yi-Fu; Li, Hong E-mail: qiutt@mail.ccnu.edu.cn E-mail: yifucai@ustc.edu.cn E-mail: xmzhang@ihep.ac.cn
2015-12-01
It is of great interest to connect cosmology in the early universe to the Standard Model of particle physics. In this paper, we try to construct a bounce inflation model with the standard model Higgs boson, where the one loop correction is taken into account in the effective potential of Higgs field. In this model, a Galileon term has been introduced to eliminate the ghost mode when bounce happens. Moreover, due to the fact that the Fermion loop correction can make part of the Higgs potential negative, one naturally obtains a large equation of state(EoS) parameter in the contracting phase, which can eliminate the anisotropy problem. After the bounce, the model can drive the universe into the standard higgs inflation phase, which can generate nearly scale-invariant power spectrum.
Unitarity check in gravitational Higgs mechanism
NASA Astrophysics Data System (ADS)
Berezhiani, Lasha; Mirbabayi, Mehrdad
2011-03-01
The effective field theory of massive gravity has long been formulated in a generally covariant way [N. Arkani-Hamed, H. Georgi, and M. D. Schwartz, Ann. Phys. (N.Y.)APNYA60003-4916 305, 96 (2003).]. Using this formalism, it has been found recently that there exists a class of massive nonlinear theories that are free of the Boulware-Deser ghosts, at least in the decoupling limit [C. de Rham and G. Gabadadze, Phys. Rev. DPRVDAQ1550-7998 82, 044020 (2010).10.1103/PhysRevD.82.044020]. In this work we study other recently proposed models that go under the name of “gravitational Higgs theories” [A. H. Chamseddine and V. Mukhanov, J. High Energy Phys.JHEPFG1029-8479 08 (2010) 011.10.1007/JHEP08(2010)011]. We show that these models, although seemingly different from the effective field theories of massive gravity, are in fact equivalent to them. Furthermore, based on the results obtained in the effective field theory approach, we conclude that the gravitational Higgs theories need the same adjustment of the Lagrangian to avoid the ghosts. We also show the equivalence between the noncovariant mode decomposition used in the Higgs theories, and the covariant Stückelberg parametrization adopted in the effective field theories, thus proving that the presence or absence of the ghost is independent of the parametrization used in either theory.
Unitarity check in gravitational Higgs mechanism
Berezhiani, Lasha; Mirbabayi, Mehrdad
2011-03-15
The effective field theory of massive gravity has long been formulated in a generally covariant way [N. Arkani-Hamed, H. Georgi, and M. D. Schwartz, Ann. Phys. (N.Y.) 305, 96 (2003).]. Using this formalism, it has been found recently that there exists a class of massive nonlinear theories that are free of the Boulware-Deser ghosts, at least in the decoupling limit [C. de Rham and G. Gabadadze, Phys. Rev. D 82, 044020 (2010).]. In this work we study other recently proposed models that go under the name of 'gravitational Higgs theories' [A. H. Chamseddine and V. Mukhanov, J. High Energy Phys. 08 (2010) 011.]. We show that these models, although seemingly different from the effective field theories of massive gravity, are in fact equivalent to them. Furthermore, based on the results obtained in the effective field theory approach, we conclude that the gravitational Higgs theories need the same adjustment of the Lagrangian to avoid the ghosts. We also show the equivalence between the noncovariant mode decomposition used in the Higgs theories, and the covariant Stueckelberg parametrization adopted in the effective field theories, thus proving that the presence or absence of the ghost is independent of the parametrization used in either theory.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; ...
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixedmore » point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.« less
NASA Astrophysics Data System (ADS)
Liu, Lijun; Gurnis, Michael
2008-08-01
temperature scaling (lower mantle viscosity) when upper-mantle (lower-mantle) density anomaly dominates the flow field; this two-stage scheme minimizes the tradeoff between temperature and lower mantle viscosity. For both cases, we show that the theory can constrain mantle properties with errors arising through the adjoint recovery of the initial condition; for the two-layer model, this error is manifest as a tradeoff between the temperature scaling and lower mantle viscosity.
Anatomizing Exotic Production of the Higgs Boson
Yu, Felix
2014-07-10
We discuss exotic production modes of the Higgs boson and how their phenomenology can be probed in current Higgs analyses. We highlight the importance of differential distributions in disentangling standard production mechanisms from exotic modes. We present two model benchmarks for exotic Higgs production arising from chargino-neutralino production and study their impact on the current Higgs dataset. As a corollary, we emphasize that current Higgs coupling fits do not fully explore the space of new physics deviations possible in Higgs data.
The Higgs portal above threshold
Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; Thalapillil, Arun
2016-02-18
The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. In this study, we systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14TeV LHC and a prospective 100TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an o ff-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. In addition, we forecast the sensitivity of searches in these channels at √s = 14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.
Adjoint Formulation for an Embedded-Boundary Cartesian Method
NASA Technical Reports Server (NTRS)
Nemec, Marian; Aftosmis, Michael J.; Murman, Scott M.; Pulliam, Thomas H.
2004-01-01
Many problems in aerodynamic design can be characterized by smooth and convex objective functions. This motivates the use of gradient-based algorithms, particularly for problems with a large number of design variables, to efficiently determine optimal shapes and configurations that maximize aerodynamic performance. Accurate and efficient computation of the gradient, however, remains a challenging task. In optimization problems where the number of design variables dominates the number of objectives and flow- dependent constraints, the cost of gradient computations can be significantly reduced by the use of the adjoint method. The problem of aerodynamic optimization using the adjoint method has been analyzed and validated for both structured and unstructured grids. The method has been applied to design problems governed by the potential, Euler, and Navier-Stokes equations and can be subdivided into the continuous and discrete formulations. Giles and Pierce provide a detailed review of both approaches. Most implementations rely on grid-perturbation or mapping procedures during the gradient computation that explicitly couple changes in the surface shape to the volume grid. The solution of the adjoint equation is usually accomplished using the same scheme that solves the governing flow equations. Examples of such code reuse include multistage Runge-Kutta schemes coupled with multigrid, approximate-factorization, line-implicit Gauss-Seidel, and also preconditioned GMRES. The development of the adjoint method for aerodynamic optimization problems on Cartesian grids has been limited. In contrast to implementations on structured and unstructured grids, Cartesian grid methods decouple the surface discretization from the volume grid. This feature makes Cartesian methods well suited for the automated analysis of complex geometry problems, and consequently a promising approach to aerodynamic optimization. Melvin e t al. developed an adjoint formulation for the TRANAIR code
Higgs searches at the Tevatron
L. Moneta
2001-06-22
This paper describes the searches for the Higgs boson performed by the CDF and DO collaborations at the Tevatron p{bar p} Collider using the data collected in the 1992-95 run. Searches for standard model Higgs and as well for neutral and charged minimal SUSY Higgs bosons are also presented. No signal has been observed and limits are set for production cross sections.
Gauge-independent Higgs mechanism and the implications for quark confinement
NASA Astrophysics Data System (ADS)
Kondo, Kei-Ichi
2017-03-01
We propose a gauge-invariant description for the Higgs mechanism by which a gauge boson acquires the mass. We do not need to assume spontaneous breakdown of gauge symmetry signaled by a non-vanishing vacuum expectation value of the scalar field. In fact, we give a manifestly gauge-invariant description of the Higgs mechanism in the operator level, which does not rely on spontaneous symmetry breaking. For concreteness, we discuss the gauge-Higgs models with U(1) and SU(2) gauge groups explicitly. This enables us to discuss the confinement-Higgs complementarity from a new perspective.
Phenomenology of the inert (2+1) and (4+2) Higgs doublet models
NASA Astrophysics Data System (ADS)
Keus, Venus; King, Stephen F.; Moretti, Stefano
2014-10-01
We make a phenomenological study of a model with two inert doublets plus one Higgs doublet [I(2+1)HDM] which is symmetric under a Z2 group, preserved after electroweak symmetry breaking by the vacuum alignment (0,0,v). This model may be regarded as an extension to the model with one inert doublet plus one Higgs doublet [I(1+1)HDM], by the addition of an extra inert scalar doublet. The neutral fields from the two inert doublets provide a viable dark matter (DM) candidate which is stabilized by the conserved Z2 symmetry. We study the new Higgs decay channels offered by the scalar fields from the extra doublets and their effect on the standard model Higgs couplings, including a new decay channel into (off-shell) photon(s) plus missing energy, which distinguishes the I(2+1)HDM from the I(1+1)HDM. Motivated by supersymmetry, which requires an even number of doublets, we then extend this model into a model with four inert doublets plus two Higgs doublets [I(4+2)HDM] and study the phenomenology of the model with the vacuum alignment (0,0,0,0,v ,v). This scenario offers a wealth of Higgs signals, the most distinctive ones being cascade decays of heavy Higgs states into inert ones. Finally, we also remark that the smoking-gun signature of all the considered models is represented by invisible Higgs decays into the lightest inert Higgs bosons responsible for DM.
Draper, P.; Liu, T.; Wagner, C. E. M.; Wang, L.-T.; Zhang, H.
2011-03-24
We study a limit of the nearly Peccei-Quinn-symmetric next-to-minimal supersymmetric standard model possessing novel Higgs and dark matter (DM) properties. In this scenario, there naturally coexist three light singletlike particles: a scalar, a pseudoscalar, and a singlinolike DM candidate, all with masses of order 0.1-10 GeV. The decay of a standard model-like Higgs boson to pairs of the light scalars or pseudoscalars is generically suppressed, avoiding constraints from collider searches for these channels. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a large direct-detection cross section consistent with the DM direct-detection experiments, CoGeNT and DAMA/LIBRA, preferred region simultaneously. This parameter space is consistent with experimental constraints from LEP, the Tevatron, ?, and flavor physics.
Using Adjoint Methods to Improve 3-D Velocity Models of Southern California
NASA Astrophysics Data System (ADS)
Liu, Q.; Tape, C.; Maggi, A.; Tromp, J.
2006-12-01
We use adjoint methods popular in climate and ocean dynamics to calculate Fréchet derivatives for tomographic inversions in southern California. The Fréchet derivative of an objective function χ(m), where m denotes the Earth model, may be written in the generic form δχ=int Km(x) δln m(x) d3x, where δln m=δ m/m denotes the relative model perturbation. For illustrative purposes, we construct the 3-D finite-frequency banana-doughnut kernel Km, corresponding to the misfit of a single traveltime measurement, by simultaneously computing the 'adjoint' wave field s† forward in time and reconstructing the regular wave field s backward in time. The adjoint wave field is produced by using the time-reversed velocity at the receiver as a fictitious source, while the regular wave field is reconstructed on the fly by propagating the last frame of the wave field saved by a previous forward simulation backward in time. The approach is based upon the spectral-element method, and only two simulations are needed to produce density, shear-wave, and compressional-wave sensitivity kernels. This method is applied to the SCEC southern California velocity model. Various density, shear-wave, and compressional-wave sensitivity kernels are presented for different phases in the seismograms. We also generate 'event' kernels for Pnl, S and surface waves, which are the Fréchet kernels of misfit functions that measure the P, S or surface wave traveltime residuals at all the receivers simultaneously for one particular event. Effectively, an event kernel is a sum of weighted Fréchet kernels, with weights determined by the associated traveltime anomalies. By the nature of the 3-D simulation, every event kernel is also computed based upon just two simulations, i.e., its construction costs the same amount of computation time as an individual banana-doughnut kernel. One can think of the sum of the event kernels for all available earthquakes, called the 'misfit' kernel, as a graphical
NASA Astrophysics Data System (ADS)
David, André Dührssen, Michael
2016-10-01
This chapter presents an overview of the measured properties of the Higgs boson discovered in 2012 by the ATLAS and CMS collaborations at the CERN LHC. Searches for deviations from the properties predicted by the standard theory are also summarised. The present status corresponds to the combined analysis of the full Run 1 data sets of collisions collected at centre-of-mass energies of 7 and 8 TeV.
Adjoint optimal control problems for the RANS system
NASA Astrophysics Data System (ADS)
Attavino, A.; Cerroni, D.; Da Vià, R.; Manservisi, S.; Menghini, F.
2017-01-01
Adjoint optimal control in computational fluid dynamics has become increasingly popular recently because of its use in several engineering and research studies. However the optimal control of turbulent flows without the use of Direct Numerical Simulation is still an open problem and various methods have been proposed based on different approaches. In this work we study optimal control problems for a turbulent flow modeled with a Reynolds-Averaged Navier-Stokes system. The adjoint system is obtained through the use of a Lagrangian multiplier method by setting as objective of the control a velocity matching profile or an increase or decrease in the turbulent kinetic energy. The optimality system is solved with an in-house finite element code and numerical results are reported in order to show the validity of this approach.
Three-Dimensional Turbulent RANS Adjoint-Based Error Correction
NASA Technical Reports Server (NTRS)
Park, Michael A.
2003-01-01
Engineering problems commonly require functional outputs of computational fluid dynamics (CFD) simulations with specified accuracy. These simulations are performed with limited computational resources. Computable error estimates offer the possibility of quantifying accuracy on a given mesh and predicting a fine grid functional on a coarser mesh. Such an estimate can be computed by solving the flow equations and the associated adjoint problem for the functional of interest. An adjoint-based error correction procedure is demonstrated for transonic inviscid and subsonic laminar and turbulent flow. A mesh adaptation procedure is formulated to target uncertainty in the corrected functional and terminate when error remaining in the calculation is less than a user-specified error tolerance. This adaptation scheme is shown to yield anisotropic meshes with corrected functionals that are more accurate for a given number of grid points then isotropic adapted and uniformly refined grids.
Quantum dissipative Higgs model
Amooghorban, Ehsan Mahdifar, Ali
2015-09-15
By using a continuum of oscillators as a reservoir, we present a classical and a quantum-mechanical treatment for the Higgs model in the presence of dissipation. In this base, a fully canonical approach is used to quantize the damped particle on a spherical surface under the action of a conservative central force, the conjugate momentum is defined and the Hamiltonian is derived. The equations of motion for the canonical variables and in turn the Langevin equation are obtained. It is shown that the dynamics of the dissipative Higgs model is not only determined by a projected susceptibility tensor that obeys the Kramers–Kronig relations and a noise operator but also the curvature of the spherical space. Due to the gnomonic projection from the spherical space to the tangent plane, the projected susceptibility displays anisotropic character in the tangent plane. To illuminate the effect of dissipation on the Higgs model, the transition rate between energy levels of the particle on the sphere is calculated. It is seen that appreciable probabilities for transition are possible only if the transition and reservoir’s oscillators frequencies to be nearly on resonance.
A comparison of adjoint and data-centric verification techniques.
Wildey, Timothy Michael; Cyr, Eric C; Shadid, John N; Pawlowski, Roger P; Smith, Thomas Michael
2013-03-01
This document summarizes the results from a level 3 milestone study within the CASL VUQ effort. We compare the adjoint-based a posteriori error estimation approach with a recent variant of a data-centric verification technique. We provide a brief overview of each technique and then we discuss their relative advantages and disadvantages. We use Drekar::CFD to produce numerical results for steady-state Navier Stokes and SARANS approximations. 3
Seismic Window Selection and Misfit Measurements for Global Adjoint Tomography
NASA Astrophysics Data System (ADS)
Lei, W.; Bozdag, E.; Lefebvre, M.; Podhorszki, N.; Smith, J. A.; Tromp, J.
2013-12-01
Global Adjoint Tomography requires fast parallel processing of large datasets. After obtaing the preprocessed observed and synthetic seismograms, we use the open source software packages FLEXWIN (Maggi et al. 2007) to select time windows and MEASURE_ADJ to make measurements. These measurements define adjoint sources for data assimilation. Previous versions of these tools work on a pair of SAC files---observed and synthetic seismic data for the same component and station, and loop over all seismic records associated with one earthquake. Given the large number of stations and earthquakes, the frequent read and write operations create severe I/O bottlenecks on modern computing platforms. We present new versions of these tools utilizing a new seismic data format, namely the Adaptive Seismic Data Format(ASDF). This new format shows superior scalability for applications on high-performance computers and accommodates various types of data, including earthquake, industry and seismic interferometry datasets. ASDF also provides user-friendly APIs, which can be easily integrated into the adjoint tomography workflow and combined with other data processing tools. In addition to solving the I/O bottleneck, we are making several improvements to these tools. For example, FLEXWIN is tuned to select windows for different types of earthquakes. To capture their distinct features, we categorize earthquakes by their depths and frequency bands. Moreover, instead of only picking phases between the first P arrival and the surface-wave arrivals, our aim is to select and assimilate many other later prominent phases in adjoint tomography. For example, in the body-wave band (17 s - 60 s), we include SKS, sSKS and their multiple, while in the surface-wave band (60 s - 120 s) we incorporate major-arc surface waves.
NASA Technical Reports Server (NTRS)
Chao, Winston C.; Chang, Lang-Ping
1992-01-01
Recent developments in the field of data assimilation have pointed to variational analysis (essentially least-squares fitting of a model solution to observed data) using the adjoint method as a new direction that holds the potential of major improvements over the current optimal interpolation method. This paper describes the initial effort in the development of a 4D variational analysis system. Although the development is based on the Goddard Laboratory for Atmospheres General Circulation Model (GCM), the methods and procedures described in this paper can be applied to any model. The adjoint code that computes the gradients needed in the analysis can be written directly from the GCM code. An easy error-detection technique was devised in the construction of the adjoint model. Also, a method of determining the weights and the preconditioning scales for the cases where model-generated data, which are error free, are used as observation is proposed. Two test experiments show that the dynamics part of the system has been successfully completed.
Generation of the Higgs condensate and its decay after inflation
Enqvist, Kari; Meriniemi, Tuukka; Nurmi, Sami E-mail: tuukka.meriniemi@helsinki.fi
2013-10-01
We investigate the dynamics of the Standard Model higgs with a minimal coupling to gravity during and after inflation. In the regime where the Standard Model vacuum is stable, we find that the higgs becomes a light spectator field after about 30 efolds of inflation, irrespectively of its initial value. Once the higgs has become light, its root-mean-square value h{sub *} relaxes to equilibrium in about 85 efolds for the inflationary scale of H{sub *} = 10{sup 4} GeV and in 20 efolds for H{sub *} = 10{sup 10} GeV. The equilibrium value is given by h{sub *} ∼ 0.36λ{sub *}{sup −1/4}H{sub *}, where λ{sub *} = 0.09...0.0005 is the higgs self coupling at the scales H{sub *} = 10{sup 4}...10{sup 10} GeV. We show that the main decay channel of the higgs condensate after inflation is the resonant production of Standard Model gauge bosons. For a set of parameters we find that a significant part of the condensate has decayed in between 340 and 630 Hubble times after the onset of higgs oscillations, depending on H{sub *} in a non-trivial way. The higgs perturbations correspond to isocurvature modes during inflation but they could generate significant adiabatic perturbations at a later stage for example through a modulation of the reheating stage. However, this requires that the inflaton(s) decay no later than a few hundred Hubble times after the onset of higgs oscillations.
Adjoint based sensitivity analysis of a reacting jet in crossflow
NASA Astrophysics Data System (ADS)
Sashittal, Palash; Sayadi, Taraneh; Schmid, Peter
2016-11-01
With current advances in computational resources, high fidelity simulations of reactive flows are increasingly being used as predictive tools in various industrial applications. In order to capture the combustion process accurately, detailed/reduced chemical mechanisms are employed, which in turn rely on various model parameters. Therefore, it would be of great interest to quantify the sensitivities of the predictions with respect to the introduced models. Due to the high dimensionality of the parameter space, methods such as finite differences which rely on multiple forward simulations prove to be very costly and adjoint based techniques are a suitable alternative. The complex nature of the governing equations, however, renders an efficient strategy in finding the adjoint equations a challenging task. In this study, we employ the modular approach of Fosas de Pando et al. (2012), to build a discrete adjoint framework applied to a reacting jet in crossflow. The developed framework is then used to extract the sensitivity of the integrated heat release with respect to the existing combustion parameters. Analyzing the sensitivities in the three-dimensional domain provides insight towards the specific regions of the flow that are more susceptible to the choice of the model.
Consistent Adjoint Driven Importance Sampling using Space, Energy and Angle
Peplow, Douglas E.; Mosher, Scott W; Evans, Thomas M
2012-08-01
For challenging radiation transport problems, hybrid methods combine the accuracy of Monte Carlo methods with the global information present in deterministic methods. One of the most successful hybrid methods is CADIS Consistent Adjoint Driven Importance Sampling. This method uses a deterministic adjoint solution to construct a biased source distribution and consistent weight windows to optimize a specific tally in a Monte Carlo calculation. The method has been implemented into transport codes using just the spatial and energy information from the deterministic adjoint and has been used in many applications to compute tallies with much higher figures-of-merit than analog calculations. CADIS also outperforms user-supplied importance values, which usually take long periods of user time to develop. This work extends CADIS to develop weight windows that are a function of the position, energy, and direction of the Monte Carlo particle. Two types of consistent source biasing are presented: one method that biases the source in space and energy while preserving the original directional distribution and one method that biases the source in space, energy, and direction. Seven simple example problems are presented which compare the use of the standard space/energy CADIS with the new space/energy/angle treatments.
Unsteady Adjoint Approach for Design Optimization of Flapping Airfoils
NASA Technical Reports Server (NTRS)
Lee, Byung Joon; Liou, Meng-Sing
2012-01-01
This paper describes the work for optimizing the propulsive efficiency of flapping airfoils, i.e., improving the thrust under constraining aerodynamic work during the flapping flights by changing their shape and trajectory of motion with the unsteady discrete adjoint approach. For unsteady problems, it is essential to properly resolving time scales of motion under consideration and it must be compatible with the objective sought after. We include both the instantaneous and time-averaged (periodic) formulations in this study. For the design optimization with shape parameters or motion parameters, the time-averaged objective function is found to be more useful, while the instantaneous one is more suitable for flow control. The instantaneous objective function is operationally straightforward. On the other hand, the time-averaged objective function requires additional steps in the adjoint approach; the unsteady discrete adjoint equations for a periodic flow must be reformulated and the corresponding system of equations solved iteratively. We compare the design results from shape and trajectory optimizations and investigate the physical relevance of design variables to the flapping motion at on- and off-design conditions.
Flavor mixing in gauge-Higgs unification
Adachi, Y.; Kurahashi, N.; Lim, C. S.; Maru, N.; Tanabe, K.
2012-07-27
Gauge-Higgs unification is the fascinating scenario solving the hierarchy problem without supersymmetry. In this scenario, the Standard Model (SM) Higgs doublet is identified with extra component of the gauge field in higher dimensions and its mass becomes finite and stable under quantum corrections due to the higher dimensional gauge symmetry. On the other hand, Yukawa coupling is provided by the gauge coupling, which seems to mean that the flavor mixing and CP violation do not arise at it stands. In this talk, we discuss that the flavor mixing is originated from simultaneously non-diagonalizable bulk and brane mass matrices. Then, this mechanism is applied to various flavor changing neutral current (FCNC) processes via Kaluza-Klein (KK) gauge boson exchange at tree level and constraints for compactification scale are obtained.
Nonlinear self-adjointness and conservation laws of Klein-Gordon-Fock equation with central symmetry
NASA Astrophysics Data System (ADS)
Abdulwahhab, Muhammad Alim
2015-05-01
The concept of nonlinear self-adjointness, introduced by Ibragimov, has significantly extends approaches to constructing conservation laws associated with symmetries since it incorporates the strict self-adjointness, the quasi self-adjointness as well as the usual linear self-adjointness. Using this concept, the nonlinear self-adjointness condition for the Klein-Gordon-Fock equation was established and subsequently used to construct simplified but infinitely many nontrivial and independent conserved vectors. The Noether's theorem was further applied to the Klein-Gordon-Fock equation to explore more distinct first integrals, result shows that conservation laws constructed through this approach are exactly the same as those obtained under strict self-adjointness of Ibragimov's method.
A new mathematical adjoint for the modified SAAF_{-SN} equations
Schunert, Sebastian; Wang, Yaqi; Martineau, Richard; DeHart, Mark D.
2015-01-01
We present a new adjoint FEM weak form, which can be directly used for evaluating the mathematical adjoint, suitable for perturbation calculations, of the self-adjoint angular flux SN equations (SAAF_{-SN}) without construction and transposition of the underlying coefficient matrix. Stabilization schemes incorporated in the described SAAF_{-SN} method make the mathematical adjoint distinct from the physical adjoint, i.e. the solution of the continuous adjoint equation with SAAF_{-SN} . This weak form is implemented into RattleSnake, the MOOSE (Multiphysics Object-Oriented Simulation Environment) based transport solver. Numerical results verify the correctness of the implementation and show its utility both for fixed source and eigenvalue problems.
Adjoint-Based Sensitivity Maps for the Nearshore
NASA Astrophysics Data System (ADS)
Orzech, Mark; Veeramony, Jay; Ngodock, Hans
2013-04-01
The wave model SWAN (Booij et al., 1999) solves the spectral action balance equation to produce nearshore wave forecasts and climatologies. It is widely used by the coastal modeling community and is part of a variety of coupled ocean-wave-atmosphere model systems. A variational data assimilation system (Orzech et al., 2013) has recently been developed for SWAN and is presently being transitioned to operational use by the U.S. Naval Oceanographic Office. This system is built around a numerical adjoint to the fully nonlinear, nonstationary SWAN code. When provided with measured or artificial "observed" spectral wave data at a location of interest on a given nearshore bathymetry, the adjoint can compute the degree to which spectral energy levels at other locations are correlated with - or "sensitive" to - variations in the observed spectrum. Adjoint output may be used to construct a sensitivity map for the entire domain, tracking correlations of spectral energy throughout the grid. When access is denied to the actual locations of interest, sensitivity maps can be used to determine optimal alternate locations for data collection by identifying regions of greatest sensitivity in the mapped domain. The present study investigates the properties of adjoint-generated sensitivity maps for nearshore wave spectra. The adjoint and forward SWAN models are first used in an idealized test case at Duck, NC, USA, to demonstrate the system's effectiveness at optimizing forecasts of shallow water wave spectra for an inaccessible surf-zone location. Then a series of simulations is conducted for a variety of different initializing conditions, to examine the effects of seasonal changes in wave climate, errors in bathymetry, and variations in size and shape of the inaccessible region of interest. Model skill is quantified using two methods: (1) a more traditional correlation of observed and modeled spectral statistics such as significant wave height, and (2) a recently developed RMS
C. Neu
2004-03-04
The Higgs boson is predicted to play a crucial role in the dynamics of electroweak symmetry breaking. The search for this yet-unseen state is an important part of the Run 2 physics program at the Tevatron. Herein is offered a brief description of the latest Run 1 Higgs results from CDF, as well as an early Run 2 result.
Higgs production through sterile neutrinos
NASA Astrophysics Data System (ADS)
Antusch, Stefan; Cazzato, Eros; Fischer, Oliver
2016-10-01
In scenarios with sterile (right-handed) neutrinos with an approximate “lepton-number-like” symmetry, the heavy neutrinos (the mass eigenstates) can have masses around the electroweak scale and couple to the Higgs boson with, in principle, unsuppressed Yukawa couplings, while the smallness of the light neutrinos’ masses is guaranteed by the approximate symmetry. The on-shell production of the heavy neutrinos at lepton colliders, together with their subsequent decays into a light neutrino and a Higgs boson, constitutes a resonant contribution to the Higgs production mechanism. This resonant mono-Higgs production mechanism can contribute significantly to the mono-Higgs observables at future lepton colliders. A dedicated search for the heavy neutrinos in this channel exhibits sensitivities for the electron neutrino Yukawa coupling as small as ˜ 5 × 10-3. Furthermore, the sensitivity is enhanced for higher center-of-mass energies, when identical integrated luminosities are considered.
Rani, K.Jyothsna; /Tata Inst.
2005-06-01
We have searched for the Standard Model (SM) and non Standard Model Higgs bosons using of about 200-260 pb{sup -1} of data collected with the upgraded Run II D0 detector at Fermilab Tevatron. Low-mass SM Higgs boson is searched in the associated production with W or Z and limits are placed on the cross section and the kinematic properties of the W or Z plus heavy flavor production. SM Higgs boson with mass greater than 135 GeV is searched for in its dominant decay mode WW with W's decaying into electron or muon final states. Non SM Higgs searches are done in the associated production of neutral SUSY Higgs with b quarks. Data are compared to various predictions and the limits are derived on model parameters.
NASA Technical Reports Server (NTRS)
Lee-Rausch, E. M.; Park, M. A.; Jones, W. T.; Hammond, D. P.; Nielsen, E. J.
2005-01-01
This paper demonstrates the extension of error estimation and adaptation methods to parallel computations enabling larger, more realistic aerospace applications and the quantification of discretization errors for complex 3-D solutions. Results were shown for an inviscid sonic-boom prediction about a double-cone configuration and a wing/body segmented leading edge (SLE) configuration where the output function of the adjoint was pressure integrated over a part of the cylinder in the near field. After multiple cycles of error estimation and surface/field adaptation, a significant improvement in the inviscid solution for the sonic boom signature of the double cone was observed. Although the double-cone adaptation was initiated from a very coarse mesh, the near-field pressure signature from the final adapted mesh compared very well with the wind-tunnel data which illustrates that the adjoint-based error estimation and adaptation process requires no a priori refinement of the mesh. Similarly, the near-field pressure signature for the SLE wing/body sonic boom configuration showed a significant improvement from the initial coarse mesh to the final adapted mesh in comparison with the wind tunnel results. Error estimation and field adaptation results were also presented for the viscous transonic drag prediction of the DLR-F6 wing/body configuration, and results were compared to a series of globally refined meshes. Two of these globally refined meshes were used as a starting point for the error estimation and field-adaptation process where the output function for the adjoint was the total drag. The field-adapted results showed an improvement in the prediction of the drag in comparison with the finest globally refined mesh and a reduction in the estimate of the remaining drag error. The adjoint-based adaptation parameter showed a need for increased resolution in the surface of the wing/body as well as a need for wake resolution downstream of the fuselage and wing trailing edge
Extension of the ADjoint Approach to a Laminar Navier-Stokes Solver
NASA Astrophysics Data System (ADS)
Paige, Cody
The use of adjoint methods is common in computational fluid dynamics to reduce the cost of the sensitivity analysis in an optimization cycle. The forward mode ADjoint is a combination of an adjoint sensitivity analysis method with a forward mode automatic differentiation (AD) and is a modification of the reverse mode ADjoint method proposed by Mader et al.[1]. A colouring acceleration technique is presented to reduce the computational cost increase associated with forward mode AD. The forward mode AD facilitates the implementation of the laminar Navier-Stokes (NS) equations. The forward mode ADjoint method is applied to a three-dimensional computational fluid dynamics solver. The resulting Euler and viscous ADjoint sensitivities are compared to the reverse mode Euler ADjoint derivatives and a complex-step method to demonstrate the reduced computational cost and accuracy. Both comparisons demonstrate the benefits of the colouring method and the practicality of using a forward mode AD. [1] Mader, C.A., Martins, J.R.R.A., Alonso, J.J., and van der Weide, E. (2008) ADjoint: An approach for the rapid development of discrete adjoint solvers. AIAA Journal, 46(4):863-873. doi:10.2514/1.29123.
Handbook of LHC Higgs Cross Sections: 3. Higgs Properties
Heinemeyer, S; et al.
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered particle such as couplings to SM particles, spin and CP-quantum numbers etc.
NASA Technical Reports Server (NTRS)
Andrews, Arlyn; Kawa, Randy; Zhu, Zhengxin; Burris, John; Abshire, Jim
2004-01-01
A detailed mechanistic understanding of the sources and sinks of CO2 will be required to reliably predict future CO2 levels and climate. A commonly used technique for deriving information about CO2 exchange with surface reservoirs is to solve an 'inverse problem', where CO2 observations are used with an atmospheric transport model to find the optimal distribution of sources and sinks. Synthesis inversion methods are powerful tools for addressing this question, but the results are disturbingly sensitive to the details of the calculation. Studies done using different atmospheric transport models and combinations of surface station data have produced substantially different distributions of surface fluxes. Adjoint methods are now being developed that will more effectively incorporate diverse datasets in estimates of surface fluxes of CO2. In an adjoint framework, it will be possible to combine CO2 concentration data from longterm surface and aircraft monitoring stations with data from intensive field campaigns and with proposed future satellite observations. We have recently developed an adjoint for the GSFC 3-D Parameterized Chemistry and Transport Model (PCTM). Here, we will present results from a PCTM Adjoint study comparing the sampling footprints of tall tower, aircraft and potential future lidar observations of CO2. The vertical resolution and extent of the profiles and the observation frequency will be considered for several sites in North America.
Search for Higgs shifts in white dwarfs
Onofrio, Roberto; Wegner, Gary A. E-mail: gary.a.wegner@dartmouth.edu
2014-08-20
We report on a search for differential shifts between electronic and vibronic transitions in carbon-rich white dwarfs BPM 27606 and Procyon B. The absence of differential shifts within the spectral resolution and taking into account systematic effects such as space motion and pressure shifts allows us to set the first upper bound of astrophysical origin on the coupling between the Higgs field and the Kreschmann curvature invariant. Our analysis provides the basis for a more general methodology to derive bounds to the coupling of long-range scalar fields to curvature invariants in an astrophysical setting complementary to the ones available from high-energy physics or table-top experiments.
Higgs CP properties from early LHC data
NASA Astrophysics Data System (ADS)
Freitas, A.; Schwaller, P.
2013-03-01
In this paper, we constrain CP violation in the Higgs sector using the measured signal strengths in the various Higgs search channels. To this end, we introduce a general parametrization for a resonance which is an admixture of a CP-even Higgs-like state and a CP-odd scalar. By performing a fit to the available data from the Tevatron and LHC experiments, one obtains constraints on the mixing angle and the couplings of the resonance to Standard Model fields. Depending on the couplings, sizable mixing angles are still compatible with the data, but small mixing is in general preferred by the fit. In particular, we find that a pure CP-odd state is disfavored by the current data at the 3σ level. Additionally, we consider a mixed fermiophobic resonance and a model with two degenerate mixed resonances and find that both scenarios can successfully fit the data within current errors. Finally, we estimate that the mixing angle can be constrained to α<1.1 (0.7) in the full 8 TeV (14 TeV) run of the LHC.
Toward realistic gauge-Higgs grand unification
NASA Astrophysics Data System (ADS)
Furui, Atsushi; Hosotani, Yutaka; Yamatsu, Naoki
2016-09-01
The SO(11) gauge-Higgs grand unification in the Randall-Sundrum warped space is presented. The 4D Higgs field is identified as the zero mode of the fifth-dimensional component of the gauge potentials, or as the fluctuation mode of the Aharonov-Bohm phase θ along the fifth dimension. Fermions are introduced in the bulk in the spinor and vector representations of SO(11). SO(11) is broken to SO(4)×SO(6) by the orbifold boundary conditions, which is broken to SU2×U1×SU3 by a brane scalar. Evaluating the effective potential V(θ), we show that the electroweak symmetry is dynamically broken to U1. The quark-lepton masses are generated by the Hosotani mechanism and brane interactions, with which the observed mass spectrum is reproduced. Proton decay is forbidden thanks to the new fermion number conservation. It is pointed out that there appear light exotic fermions. The Higgs boson mass is determined with the quark-lepton masses given; however, it turns out to be smaller than the observed value.
Ultra-weak sector, Higgs boson mass, and the dilaton
Allison, Kyle; Hill, Christopher T.; Ross, Graham G.
2014-09-26
The Higgs boson mass may arise from a portal coupling to a singlet field $\\sigma$ which has a very large VEV $f \\gg m_\\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\\zeta_i$, where $\\zeta_i \\lesssim m_\\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\\sigma$ in the $\\zeta_i \\rightarrow 0$ limit. The singlet field $\\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.
Exotic quarks in Twin Higgs models
Cheng, Hsin -Chia; Jung, Sunghoon; Salvioni, Ennio; Tsai, Yuhsin
2016-03-14
The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ~ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of the model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. As a result, depending on the details of the twin sector, the exotic quarks may be probed up to ~ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.
Exotic quarks in Twin Higgs models
Cheng, Hsin -Chia; Jung, Sunghoon; Salvioni, Ennio; ...
2016-03-14
The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ~ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of themore » model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. As a result, depending on the details of the twin sector, the exotic quarks may be probed up to ~ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.« less
The RG-improved Twin Higgs effective potential at NNLL
NASA Astrophysics Data System (ADS)
Greco, Davide; Mimouni, Kin
2016-11-01
We present the Renormalization Group improvement of the Twin Higgs effective potential at cubic order in logarithmic accuracy. We first introduce a model-independent low-energy effective Lagrangian that captures both the pseudo-Nambu-Goldstone boson nature of the Higgs field and the twin light degrees of freedom charged under a copy of the Standard Model. We then apply the background field method to systematically re-sum all the one loop diagrams contributing to the potential. We show how this technique can be efficient to implicitly renormalize the higher-dimensional operators in the twin sector without classifying all of them. A prediction for the Higgs mass in the Twin Higgs model is derived and found to be of the order of M H ˜ 120 GeV with an ultraviolet cut-off m * ˜ 10-20 TeV. Irrespective of any possible ultraviolet completion of the low-energy Lagrangian, the infrared degrees of freedom alone are therefore enough to account for the observed value of the Higgs mass through running effects.
Exotic Higgs decay via charged Higgs
NASA Astrophysics Data System (ADS)
Li, Tong; Su, Shufang
2015-11-01
The most common search channel for heavy neutral Higgses in models with an extension of the Standard Model Higgs sector is A/H 0 → ττ which becomes ineffective when new decay modes of A/H 0 open. In this paper, we analyzed two such channels involving charged Higgses in the final states: A/H 0 → W ± H ∓ and H 0 → H + H -. With the consequent decay of H ± → τν, we found that the limits for σ × BR( gg → A/H 0 → W ± H ∓) × BR( H ± → τν) vary from 30 to 10fb for m A/ H 0 between 300 and 1000GeV for 95% C.L. exclusion, and about 80 to 30 fb for 5 σ discovery. For H + H - mode, 95% C.L. limits on σ × BR( gg → H 0 → H + H -) × BR2( H ± → τν) vary from 9 to 4 fb for m H 0 between 400 and 1000 GeV, while the 5σ reach is about 20 to 10 fb. We further interpret the cross section limits in the Type II 2HDM parameter space. While A → W ± H ∓ offers great sensitivity in both sin( β - α) versus tan β and m A versus tan β parameter space, H 0 → H + H - can cover most of the parameter space for H 0. Reach in H 0 → W ± H ∓ is more limited, especially for m H 0 > 2 m H ± . It is, however, complementary to H 0 → H + H - when BR( H 0 → H + H -) is accidentally suppressed.
On the origins and the historical roots of the Higgs boson research from a bibliometric perspective
NASA Astrophysics Data System (ADS)
Barth, A.; Marx, W.; Bornmann, L.; Mutz, R.
2014-06-01
The subject of our present paper is the analysis of the origins or historical roots of the Higgs boson research from a bibliometric perspective, using a segmented regression analysis in combination with a method named reference publication year spectroscopy (RPYS). Our analysis is based on the references cited in the Higgs boson publications published since 1974. The objective of our analysis consists of identifying specific individual publications in the Higgs boson research context to which the scientific community frequently had referred to. We are interested in seminal works which contributed to a high extent to the discovery of the Higgs boson. Our results show that researchers in the Higgs boson field preferably refer to more recently published papers —particularly papers published since the beginning of the sixties. For example, our analysis reveals seven major contributions which appeared within the sixties: Englert and Brout (1964), Higgs (1964, 2 papers), and Guralnik et al. (1964) on the Higgs mechanism as well as Glashow (1961), Weinberg (1967), and Salam (1968) on the unification of weak and electromagnetic interaction. Even if the Nobel Prize award highlights the outstanding importance of the work of Peter Higgs and Francois Englert, bibliometrics offer the additional possibility of getting hints to other publications in this research field (especially to historical publications), which are of vital importance from the expert point of view.
Data assimilation for massive autonomous systems based on a second-order adjoint method
NASA Astrophysics Data System (ADS)
Ito, Shin-ichi; Nagao, Hiromichi; Yamanaka, Akinori; Tsukada, Yuhki; Koyama, Toshiyuki; Kano, Masayuki; Inoue, Junya
2016-10-01
Data assimilation (DA) is a fundamental computational technique that integrates numerical simulation models and observation data on the basis of Bayesian statistics. Originally developed for meteorology, especially weather forecasting, DA is now an accepted technique in various scientific fields. One key issue that remains controversial is the implementation of DA in massive simulation models under the constraints of limited computation time and resources. In this paper, we propose an adjoint-based DA method for massive autonomous models that produces optimum estimates and their uncertainties within reasonable computation time and resource constraints. The uncertainties are given as several diagonal elements of an inverse Hessian matrix, which is the covariance matrix of a normal distribution that approximates the target posterior probability density function in the neighborhood of the optimum. Conventional algorithms for deriving the inverse Hessian matrix require O (C N2+N3) computations and O (N2) memory, where N is the number of degrees of freedom of a given autonomous system and C is the number of computations needed to simulate time series of suitable length. The proposed method using a second-order adjoint method allows us to directly evaluate the diagonal elements of the inverse Hessian matrix without computing all of its elements. This drastically reduces the number of computations to O (C ) and the amount of memory to O (N ) for each diagonal element. The proposed method is validated through numerical tests using a massive two-dimensional Kobayashi phase-field model. We confirm that the proposed method correctly reproduces the parameter and initial state assumed in advance, and successfully evaluates the uncertainty of the parameter. Such information regarding uncertainty is valuable, as it can be used to optimize the design of experiments.
The Higgs Portal and Cosmology
Assamagan, Ketevi; Chien-Yi Chen; Chou, John Paul; Curtin, David; Fedderke, Michael A.; Gershtein, Yuri; He, Xiao-Gang; Klute, Markus; Kozaczuk, Jonathon; Kotwal, Ashutosh; Lowette, Steven; No, Jose Miguel; Plehn, Tilman; Qian, Jianming; Ramsey-Musolf, Michael; Safonov, Alexei; Shelton, Jessie; Spannowsky, Michael; Su, Shufang; Walker, Devin G. E.; Willocq, Stephane; Winslow, Peter
2016-04-18
Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first-order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.
Adjoint Techniques for Topology Optimization of Structures Under Damage Conditions
NASA Technical Reports Server (NTRS)
Akgun, Mehmet A.; Haftka, Raphael T.
2000-01-01
The objective of this cooperative agreement was to seek computationally efficient ways to optimize aerospace structures subject to damage tolerance criteria. Optimization was to involve sizing as well as topology optimization. The work was done in collaboration with Steve Scotti, Chauncey Wu and Joanne Walsh at the NASA Langley Research Center. Computation of constraint sensitivity is normally the most time-consuming step of an optimization procedure. The cooperative work first focused on this issue and implemented the adjoint method of sensitivity computation (Haftka and Gurdal, 1992) in an optimization code (runstream) written in Engineering Analysis Language (EAL). The method was implemented both for bar and plate elements including buckling sensitivity for the latter. Lumping of constraints was investigated as a means to reduce the computational cost. Adjoint sensitivity computation was developed and implemented for lumped stress and buckling constraints. Cost of the direct method and the adjoint method was compared for various structures with and without lumping. The results were reported in two papers (Akgun et al., 1998a and 1999). It is desirable to optimize topology of an aerospace structure subject to a large number of damage scenarios so that a damage tolerant structure is obtained. Including damage scenarios in the design procedure is critical in order to avoid large mass penalties at later stages (Haftka et al., 1983). A common method for topology optimization is that of compliance minimization (Bendsoe, 1995) which has not been used for damage tolerant design. In the present work, topology optimization is treated as a conventional problem aiming to minimize the weight subject to stress constraints. Multiple damage configurations (scenarios) are considered. Each configuration has its own structural stiffness matrix and, normally, requires factoring of the matrix and solution of the system of equations. Damage that is expected to be tolerated is local
Advances in Global Adjoint Tomography -- Massive Data Assimilation
NASA Astrophysics Data System (ADS)
Ruan, Y.; Lei, W.; Bozdag, E.; Lefebvre, M. P.; Smith, J. A.; Krischer, L.; Tromp, J.
2015-12-01
Azimuthal anisotropy and anelasticity are key to understanding a myriad of processes in Earth's interior. Resolving these properties requires accurate simulations of seismic wave propagation in complex 3-D Earth models and an iterative inversion strategy. In the wake of successes in regional studies(e.g., Chen et al., 2007; Tape et al., 2009, 2010; Fichtner et al., 2009, 2010; Chen et al.,2010; Zhu et al., 2012, 2013; Chen et al., 2015), we are employing adjoint tomography based on a spectral-element method (Komatitsch & Tromp 1999, 2002) on a global scale using the supercomputer ''Titan'' at Oak Ridge National Laboratory. After 15 iterations, we have obtained a high-resolution transversely isotropic Earth model (M15) using traveltime data from 253 earthquakes. To obtain higher resolution images of the emerging new features and to prepare the inversion for azimuthal anisotropy and anelasticity, we expanded the original dataset with approximately 4,220 additional global earthquakes (Mw5.5-7.0) --occurring between 1995 and 2014-- and downloaded 300-minute-long time series for all available data archived at the IRIS Data Management Center, ORFEUS, and F-net. Ocean Bottom Seismograph data from the last decade are also included to maximize data coverage. In order to handle the huge dataset and solve the I/O bottleneck in global adjoint tomography, we implemented a python-based parallel data processing workflow based on the newly developed Adaptable Seismic Data Format (ASDF). With the help of the data selection tool MUSTANG developed by IRIS, we cleaned our dataset and assembled event-based ASDF files for parallel processing. We have started Centroid Moment Tensors (CMT) inversions for all 4,220 earthquakes with the latest model M15, and selected high-quality data for measurement. We will statistically investigate each channel using synthetic seismograms calculated in M15 for updated CMTs and identify problematic channels. In addition to data screening, we also modified
A self-adjoint decomposition of the radial momentum operator
NASA Astrophysics Data System (ADS)
Liu, Q. H.; Xiao, S. F.
2015-12-01
With acceptance of the Dirac's observation that the canonical quantization entails using Cartesian coordinates, we examine the operator erPr rather than Pr itself and demonstrate that there is a decomposition of erPr into a difference of two self-adjoint but noncommutative operators, in which one is the total momentum and another is the transverse one. This study renders the operator Pr indirectly measurable and physically meaningful, offering an explanation of why the mean value of Pr over a quantum mechanical state makes sense and supporting Dirac's claim that Pr "is real and is the true momentum conjugate to r".
NASA Technical Reports Server (NTRS)
Diosady, Laslo; Murman, Scott; Blonigan, Patrick; Garai, Anirban
2017-01-01
Presented space-time adjoint solver for turbulent compressible flows. Confirmed failure of traditional sensitivity methods for chaotic flows. Assessed rate of exponential growth of adjoint for practical 3D turbulent simulation. Demonstrated failure of short-window sensitivity approximations.
2015-11-10
Accepted 12 October 2015 Available online 10 November 2015 Keywords: Data assimilation Ajoint analysis Regional modeling a b s t r a c t Performance of...the adjoint and adjoint-free 4-dimensional variational (4dVar) data assimilation techniques is compared in application to the hydrographic surveys...and velocity observations collected in the Adriatic Sea in 2006. Assimilating the data into the Navy Coastal Ocean Model (NCOM) has shown that both
Phenomenology in the Higgs triplet model with the A4 symmetry
NASA Astrophysics Data System (ADS)
Fukuyama, Takeshi; Sugiyama, Hiroaki; Tsumura, Koji
2010-08-01
We discuss the phenomenology of doubly and singly charged Higgs bosons [of SU(2)L-triplet fields] in the simplest A4-symmetric version of the Higgs triplet model. Mass eigenstates of these Higgs bosons are obtained explicitly from the Higgs potential. It is shown that their decays into a pair of leptons have unique flavor structures which can be tested at the LHC if some of their masses are below the TeV scale. Sizable decay rates for τ→μ¯ee and τ→ēμμ can be obtained naturally, while other τ→ℓ¯ℓ'ℓ'', μ→ēee, and ℓ→ℓ'γ, are almost forbidden in this model. Contributions of these Higgs bosons to the nonstandard interactions of neutrinos are also considered.
Limits on Higgs bosons, scalar-quarkonia, and ηb's from radiative upsilon decays
NASA Astrophysics Data System (ADS)
Franzini, P.; Son, D.; Tuts, P. M.; Youssef, S.; Zhao, T.; Lee-Franzini, J.; Horstkotte, J.; Klopfenstein, C.; Kaarsberg, T.; Lovelock, D. M. J.; Schamberger, R. D.; Sontz, S. B.; Yanagisawa, C.
1987-05-01
We have searched for monochromatic photon signals in the reaction Υ(9460)-->X+γ in a sample of 420 000 Υ decays observed in the CUSB detector. From the absence of signal we obtain upper limits for Higgs-boson production in Υ decay which approach the minimal-standard-model expectations, including QCD radiative corrections, for low Higgs-boson masses. For two Higgs-boson models we obtain bounds on the ratio of the vacuum expectation values of the two neutral Higgs fields as a function of the Higgs-boson mass. We do not confirm the ζ(8.3) and find no evidence for a nearby bound scalar-quark-anti-scalar-quark state. We obtain a lower bound for the ηb mass using potential-model predictions.
Phenomenology in the Higgs triplet model with the A{sub 4} symmetry
Fukuyama, Takeshi; Sugiyama, Hiroaki; Tsumura, Koji
2010-08-01
We discuss the phenomenology of doubly and singly charged Higgs bosons [of SU(2){sub L}-triplet fields] in the simplest A{sub 4}-symmetric version of the Higgs triplet model. Mass eigenstates of these Higgs bosons are obtained explicitly from the Higgs potential. It is shown that their decays into a pair of leptons have unique flavor structures which can be tested at the LHC if some of their masses are below the TeV scale. Sizable decay rates for {tau}{yields}{mu}ee and {tau}{yields}e{mu}{mu} can be obtained naturally, while other {tau}{yields}ll{sup '}l{sup ''}, {mu}{yields}eee, and l{yields}l{sup '{gamma}}, are almost forbidden in this model. Contributions of these Higgs bosons to the nonstandard interactions of neutrinos are also considered.
Kim, Min-Geun; Jang, Hong-Lae; Cho, Seonho
2013-05-01
An efficient adjoint design sensitivity analysis method is developed for reduced atomic systems. A reduced atomic system and the adjoint system are constructed in a locally confined region, utilizing generalized Langevin equation (GLE) for periodic lattice structures. Due to the translational symmetry of lattice structures, the size of time history kernel function that accounts for the boundary effects of the reduced atomic systems could be reduced to a single atom’s degrees of freedom. For the problems of highly nonlinear design variables, the finite difference method is impractical for its inefficiency and inaccuracy. However, the adjoint method is very efficient regardless of the number of design variables since one additional time integration is required for the adjoint GLE. Through numerical examples, the derived adjoint sensitivity turns out to be accurate and efficient through the comparison with finite difference sensitivity.
Higgs searches at the Tevatron
Mastrandrea, Paolo; /INFN, Siena
2010-09-01
The search for the Standard Model Higgs boson in p{bar p} collisions at 1.96 TeV performed by CDF and D0 collaborations at the Tevatron collider is reported in this paper. The Higgs candidate events are reconstructed using different final states in order to optimize the sensitivity in the full range of the Higgs mass. The presented results use different statistical samples collected by the Tevatron up to 5.9 fb{sup -1}. Combining the most updated limits provided by the two experiments for all the final states analyzed, the Standard Model Higgs boson is excluded at 95% C.L. in the mass range 158-175 GeV/c{sup 2}, in good agreement with the prediction for the analyzed data sample.
Lincoln, Don
2011-07-07
Fermilab scientist Don Lincoln describes the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass.
Lincoln, Don
2016-07-12
Fermilab scientist Don Lincoln describes the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass.
Higgs phenomenology in warped extra dimensions with a fourth generation
Frank, Mariana; Korutlu, Beste; Toharia, Manuel
2011-10-01
We study a warped extra-dimension scenario where the standard model fields lie in the bulk, with the addition of a fourth family of fermions. We concentrate on the flavor structure of the Higgs couplings with fermions in the flavor anarchy ansatz. Even without a fourth family, these couplings will be generically misaligned with respect to the standard model fermion mass matrices. The presence of the fourth family typically enhances the misalignment effects and we show that one should expect them to be highly nonsymmetrical in the (34) intergenerational mixing. The radiative corrections from the new fermions and their flavor-violating couplings to the Higgs affect negligibly known experimental precision measurements such as the oblique parameters and Z{yields}bb or Z{yields}{mu}{sup +}{mu}{sup -}. On the other hand, {Delta}F=1, 2 processes, mediated by tree-level Higgs exchange, as well as radiative corrections to b{yields}s{gamma} and {mu}{yields}e{gamma} put some generic pressure on the allowed size of the flavor-violating couplings. But more importantly, these couplings will alter the Higgs decay patterns as well as those of the new fermions, and produce very interesting new signals associated to Higgs phenomenology in high energy colliders. These signals might become very important indirect signals for these type of models as they would be present even when the KK mass scale is high and no heavy KK particle is discovered.
Radiative PQ breaking and the Higgs boson mass
NASA Astrophysics Data System (ADS)
D'Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio
2015-06-01
The small and negative value of the Standard Model Higgs quartic coupling at high scales can be understood in terms of anthropic selection on a landscape where large and negative values are favored: most universes have a very short-lived electroweak vacuum and typical observers are in universes close to the corresponding metastability boundary. We provide a simple example of such a landscape with a Peccei-Quinn symmetry breaking scale generated through dimensional transmutation and supersymmetry softly broken at an intermediate scale. Large and negative contributions to the Higgs quartic are typically generated on integrating out the saxion field. Cancellations among these contributions are forced by the anthropic requirement of a sufficiently long-lived electroweak vacuum, determining the multiverse distribution for the Higgs quartic in a similar way to that of the cosmological constant. This leads to a statistical prediction of the Higgs boson mass that, for a wide range of parameters, yields the observed value within the 1σ statistical uncertainty of ˜ 5 GeV originating from the multiverse distribution. The strong CP problem is solved and single-component axion dark matter is predicted, with an abundance that can be understood from environmental selection. A more general setting for the Higgs mass prediction is discussed.
Higgs-flavon mixing and h → μτ
NASA Astrophysics Data System (ADS)
Huitu, Katri; Keus, Venus; Koivunen, Niko; Lebedev, Oleg
2016-05-01
ATLAS and CMS have reported an excess in the flavor violating decay of the Higgs boson, h → μτ . We show that this result can be accommodated through a mixing of the Higgs with a flavon, the field responsible for generating the Yukawa matrices in the lepton sector. We employ a version of the Froggatt-Nielsen mechanism at the electroweak scale, with only the leptons and the flavon transforming non-trivially under the corresponding symmetry group. Non-observation of charged lepton flavor violation (LFV) in other processes imposes important constraints on the model, which we find to be satisfied in substantial regions of parameter space.
The little skyrmion: new dark matter for little Higgs models
NASA Astrophysics Data System (ADS)
Gillioz, Marc; von Manteuffel, Andreas; Schwaller, Pedro; Wyler, Daniel
2011-03-01
We study skyrmions in the littlest Higgs model and discuss their possible role as dark matter candidates. Stable massive skyrmions can exist in the littlest Higgs model also in absence of an exact parity symmetry, since they carry a conserved topological charge due to the non-trivial third homotopy group of the SU(5)/SO(5) coset. We find a spherically symmetric skyrmion solution in this coset. The effects of gauge fields on the skyrmion solutions are analyzed and found to lead to an upper bound on the skyrmion mass. The relic abundance is in agreement with the observed dark matter density for reasonable parameter choices.
Probing the fermionic Higgs portal at lepton colliders
Fedderke, Michael A.; Lin, Tongyan; Wang, Lian -Tao
2016-04-26
Here, we study the sensitivity of future electron-positron colliders to UV completions of the fermionic Higgs portal operator H†Hχ¯χ. Measurements of precision electroweak S and T parameters and the e+e– → Zh cross-section at the CEPC, FCC-ee, and ILC are considered. The scalar completion of the fermionic Higgs portal is closely related to the scalar Higgs portal, and we summarize existing results. We devote the bulk of our analysis to a singlet-doublet fermion completion. Assuming the doublet is sufficiently heavy, we construct the effective field theory (EFT) at dimension-6 in order to compute contributions to the observables. We also providemore » full one-loop results for S and T in the general mass parameter space. In both completions, future precision measurements can probe the new states at the (multi-)TeV scale, beyond the direct reach of the LHC.« less
Higgs boson production and decay in 5D warped models
NASA Astrophysics Data System (ADS)
Frank, Mariana; Pourtolami, Nima; Toharia, Manuel
2016-03-01
We calculate the production and decay rates of the Higgs boson at the LHC in the context of general five-dimensional warped scenarios with a spacetime background modified from the usual AdS5 , with Standard Model (SM) fields propagating in the bulk. We extend previous work by considering the full flavor structure of the SM, and thus including all possible flavor effects coming from mixings with heavy fermions. We proceed in three different ways, first by only including two complete Kaluza-Klein (KK) levels (15 ×15 fermion mass matrices), then including three complete KK levels (21 ×21 fermion mass matrices) and finally we compare with the effect of including the infinite (full) KK towers. We present numerical results for the Higgs production cross section via gluon fusion and Higgs decay branching fractions in both the modified metric scenario and in the usual Randall-Sundrum metric scenario.
Symmetry breaking patterns for little Higgs models from strong dynamics
Batra, Puneet; Chacko, Z.
2008-03-01
We show how the symmetry breaking pattern of the simplest little Higgs model, and that of the smallest moose model that incorporates an approximate custodial SU(2), can be realized through the condensation of strongly coupled fermions. In each case a custodial SU(2) symmetry of the new strong dynamics limits the sizes of corrections to precision electroweak observables. In the case of the simplest little Higgs, there are no new light states beyond those present in the original model. However, our realization of the symmetry breaking pattern of the moose model predicts an additional scalar field with mass of order a TeV or higher that has exactly the same quantum numbers as the standard model Higgs and which decays primarily to third generation quarks.
Unitarity-violation in generalized Higgs inflation models
Lerner, Rose N.; McDonald, John E-mail: j.mcdonald@lancaster.ac.uk
2012-11-01
Unitarity-violation presents a challenge for non-minimally coupled models of inflation based on weak-scale particle physics. We examine the energy scale of tree-level unitarity-violation in scattering processes for generalized models with multiple scalar fields where the inflaton is either a singlet scalar or the Higgs. In the limit that the non-minimal couplings are all equal (e.g. in the case of Higgs or other complex inflaton), the scale of tree-level unitarity-violation matches the existing result. However if the inflaton is a singlet, and if it has a larger non-minimal coupling than other scalars in the model, then this hierarchy increases the scale of tree-level unitarity-violation. A sufficiently strong hierarchy pushes the scale of tree-level unitarity-violation above the Planck scale. We also discuss models which attempt to resolve the issue of unitarity-violation in Higgs Inflation.
Higgs mechanism and the added-mass effect.
Krishnaswami, Govind S; Phatak, Sachin S
2015-04-08
In the Higgs mechanism, mediators of the weak force acquire masses by interacting with the Higgs condensate, leading to a vector boson mass matrix. On the other hand, a rigid body accelerated through an inviscid, incompressible and irrotational fluid feels an opposing force linearly related to its acceleration, via an added-mass tensor. We uncover a striking physical analogy between the two effects and propose a dictionary relating them. The correspondence turns the gauge Lie algebra into the space of directions in which the body can move, encodes the pattern of gauge symmetry breaking in the shape of an associated body and relates symmetries of the body to those of the scalar vacuum manifold. The new viewpoint is illustrated with numerous examples, and raises interesting questions, notably on the fluid analogues of the broken symmetry and Higgs particle, and the field-theoretic analogue of the added mass of a composite body.
Higgs mechanism and the added-mass effect
Krishnaswami, Govind S.; Phatak, Sachin S.
2015-01-01
In the Higgs mechanism, mediators of the weak force acquire masses by interacting with the Higgs condensate, leading to a vector boson mass matrix. On the other hand, a rigid body accelerated through an inviscid, incompressible and irrotational fluid feels an opposing force linearly related to its acceleration, via an added-mass tensor. We uncover a striking physical analogy between the two effects and propose a dictionary relating them. The correspondence turns the gauge Lie algebra into the space of directions in which the body can move, encodes the pattern of gauge symmetry breaking in the shape of an associated body and relates symmetries of the body to those of the scalar vacuum manifold. The new viewpoint is illustrated with numerous examples, and raises interesting questions, notably on the fluid analogues of the broken symmetry and Higgs particle, and the field-theoretic analogue of the added mass of a composite body. PMID:27547077
Ultra-weak sector, Higgs boson mass, and the dilaton
Allison, Kyle; Hill, Christopher T.; Ross, Graham G.
2014-09-26
The Higgs boson mass may arise from a portal coupling to a singlet fieldmore » $$\\sigma$$ which has a very large VEV $$f \\gg m_\\text{Higgs}$$. This requires a sector of "ultra-weak" couplings $$\\zeta_i$$, where $$\\zeta_i \\lesssim m_\\text{Higgs}^2 / f^2$$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $$\\sigma$$ in the $$\\zeta_i \\rightarrow 0$$ limit. The singlet field $$\\sigma$$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.« less
Probing the fermionic Higgs portal at lepton colliders
Fedderke, Michael A.; Lin, Tongyan; Wang, Lian -Tao
2016-04-26
Here, we study the sensitivity of future electron-positron colliders to UV completions of the fermionic Higgs portal operator H^{†}Hχ¯χ. Measurements of precision electroweak S and T parameters and the e^{+}e^{–} → Zh cross-section at the CEPC, FCC-ee, and ILC are considered. The scalar completion of the fermionic Higgs portal is closely related to the scalar Higgs portal, and we summarize existing results. We devote the bulk of our analysis to a singlet-doublet fermion completion. Assuming the doublet is sufficiently heavy, we construct the effective field theory (EFT) at dimension-6 in order to compute contributions to the observables. We also provide full one-loop results for S and T in the general mass parameter space. In both completions, future precision measurements can probe the new states at the (multi-)TeV scale, beyond the direct reach of the LHC.
The Higgs portal above threshold
Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; ...
2016-02-18
The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. In this study, we systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14TeV LHC and a prospective 100TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an o ff-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy inmore » association with vector boson fusion, monojets, and top pairs. In addition, we forecast the sensitivity of searches in these channels at √s = 14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.« less
Can We Tell Students where the Higgs Boson Lies?
ERIC Educational Resources Information Center
Chu, Z. Kwang-Hua
2010-01-01
We pedagogically introduce the search for the Higgs boson and the measurement of its properties which will be one of the primary goals of the Large Hadron Collider. Our presentation will be useful to the relevant graduate and senior undergraduate students studying physics, as well as researchers in this field. (Contains 1 figure.)
Inflection-point B -L Higgs inflation
NASA Astrophysics Data System (ADS)
Okada, Nobuchika; Raut, Digesh
2017-02-01
Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass (ϕI≲MPl). In order for a renormalization group (RG) improved effective λ ϕ4 potential to develop an inflection point, the quartic coupling λ (ϕ ) must exhibit a minimum with an almost vanishing value in its RG evolution, namely λ (ϕI)≃0 and βλ(ϕI)≃0 , where βλ is the beta function of the quartic coupling. As an example, we consider the minimal gauged B -L extended Standard Model at the TeV scale, where we identify the B -L Higgs field as the inflaton field. For a successful inflection-point inflation, which is consistent with the current cosmological observations, the mass ratios among the Z' gauge boson, the right-handed neutrinos and the B -L Higgs boson are fixed. Our scenario can be tested in the future collider experiments such as the high-luminosity LHC and the SHiP experiments. In addition, the inflection-point inflation provides a unique prediction for the running of the spectral index α ≃-2.7 ×10-3(60/N) 2 (N is the e -folding number), which can be tested in the near future.
Sakurai Prize: The Future of Higgs Physics
NASA Astrophysics Data System (ADS)
Dawson, Sally
2017-01-01
The discovery of the Higgs boson relied critically on precision calculations. The quantum contributions from the Higgs boson to the W and top quark masses suggested long before the Higgs discovery that a Standard Model Higgs boson should have a mass in the 100-200 GeV range. The experimental extraction of Higgs properties requires normalization to the predicted Higgs production and decay rates, for which higher order corrections are also essential. As Higgs physics becomes a mature subject, more and more precise calculations will be required. If there is new physics at high scales, it will contribute to the predictions and precision Higgs physics will be a window to beyond the Standard Model physics.
T-Parity in Little Higgs Models
Krohn, David
2008-11-23
We examine quantum anomalies in the context of little Higgs theories. In particular, we investigate the restrictions imposed upon little Higgs models when one requires an exact T-parity. Applications to LHC phenomenology are briefly discussed.
Twin Higgs mechanism and a composite Higgs boson
NASA Astrophysics Data System (ADS)
Low, Matthew; Tesi, Andrea; Wang, Lian-Tao
2015-05-01
We combine the twin Higgs mechanism with the paradigm of composite Higgs models. In this class of models the Higgs is a pseudo-Nambu-Goldstone boson from a strongly coupled sector near the TeV scale, and it is additionally protected by a discrete symmetry due to the twin mechanism. We discuss the model-building issues associated with this setup and quantify the tuning needed to achieve the correct electroweak vacuum and the Higgs mass. In contrast to standard composite Higgs models, the lightest resonance associated with the top sector is the uncolored mirror top, while the colored top partners can be made parameterically heavier without extra tuning. In some cases, the vector resonances are predicted to lie in the multi-TeV range. We present models where the resonances—both fermions and vectors—being heavier alleviates the pressure on naturalness coming from direct searches demonstrating that theories with low tuning may survive constraints from the Large Hadron Collider.
NASA Astrophysics Data System (ADS)
Parkinson, Samuel D.; Funke, Simon W.; Hill, Jon; Piggott, Matthew D.; Allison, Peter A.
2017-03-01
Turbidity currents are one of the main drivers of sediment transport from the continental shelf to the deep ocean. The resulting sediment deposits can reach hundreds of kilometres into the ocean. Computer models that simulate turbidity currents and the resulting sediment deposit can help us to understand their general behaviour. However, in order to recreate real-world scenarios, the challenge is to find the turbidity current parameters that reproduce the observations of sediment deposits. This paper demonstrates a solution to the inverse sediment transportation problem: for a known sedimentary deposit, the developed model reconstructs details about the turbidity current that produced the deposit. The reconstruction is constrained here by a shallow water sediment-laden density current model, which is discretised by the finite-element method and an adaptive time-stepping scheme. The model is differentiated using the adjoint approach, and an efficient gradient-based optimisation method is applied to identify the turbidity parameters which minimise the misfit between the modelled and the observed field sediment deposits. The capabilities of this approach are demonstrated using measurements taken in the Miocene Marnoso-arenacea Formation (Italy). We find that whilst the model cannot match the deposit exactly due to limitations in the physical processes simulated, it provides valuable insights into the depositional processes and represents a significant advance in our toolset for interpreting turbidity current deposits.
Unsteady adjoint for large eddy simulation of a coupled turbine stator-rotor system
NASA Astrophysics Data System (ADS)
Talnikar, Chaitanya; Wang, Qiqi; Laskowski, Gregory
2016-11-01
Unsteady fluid flow simulations like large eddy simulation are crucial in capturing key physics in turbomachinery applications like separation and wake formation in flow over a turbine vane with a downstream blade. To determine how sensitive the design objectives of the coupled system are to control parameters, an unsteady adjoint is needed. It enables the computation of the gradient of an objective with respect to a large number of inputs in a computationally efficient manner. In this paper we present unsteady adjoint solutions for a coupled turbine stator-rotor system. As the transonic fluid flows over the stator vane, the boundary layer transitions to turbulence. The turbulent wake then impinges on the rotor blades, causing early separation. This coupled system exhibits chaotic dynamics which causes conventional adjoint solutions to diverge exponentially, resulting in the corruption of the sensitivities obtained from the adjoint solutions for long-time simulations. In this presentation, adjoint solutions for aerothermal objectives are obtained through a localized adjoint viscosity injection method which aims to stabilize the adjoint solution and maintain accurate sensitivities. Preliminary results obtained from the supercomputer Mira will be shown in the presentation.
Bound states in the Higgs model
NASA Astrophysics Data System (ADS)
di Leo, Leo; Darewych, Jurij W.
1994-02-01
We derive relativistic wave equations for the bound states of two Higgs bosons within the Higgs sector of the minimal standard model. The variational method and the Hamiltonian formalism of QFT are used to obtain the equations using a simple ||hh>+||hhh> Fock-space ansatz. We present approximate solutions of these equations for a range of Higgs boson masses, and explore the parameter space which corresponds to the existence of two-Higgs-boson bound states.
Measuring Higgs couplings from LHC data.
Klute, Markus; Lafaye, Rémi; Plehn, Tilman; Rauch, Michael; Zerwas, Dirk
2012-09-07
Following recent ATLAS and CMS publications we interpret the results of their Higgs searches in terms of standard model operators. For a Higgs boson mass of 125 GeV we determine several Higgs couplings from published 2011 data and extrapolate the results towards different scenarios of LHC running. Even though our analysis is limited by low statistics we already derive meaningful constraints on modified Higgs sectors.
THE HIGGS WORKING GROUP: SUMMARY REPORT.
DAWSON, S.; ET AL.
2005-08-01
This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e{sup +}e{sup -} collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg {yields} H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan {beta} and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e{sup +}e{sup -} collider.
Is the Higgs boson composed of neutrinos?
Krog, Jens; Hill, Christopher T.
2015-11-09
We show that conventional Higgs compositeness conditions can be achieved by the running of large Higgs-Yukawa couplings involving right-handed neutrinos that become active at ~1013–1014 GeV. Together with a somewhat enhanced quartic coupling arising by a Higgs portal interaction to a dark matter sector, we can obtain a Higgs boson composed of neutrinos. Furthermore, this is a “next-to-minimal” dynamical electroweak symmetry breaking scheme.
Is the Higgs boson composed of neutrinos?
Krog, Jens; Hill, Christopher T.
2015-11-09
We show that conventional Higgs compositeness conditions can be achieved by the running of large Higgs-Yukawa couplings involving right-handed neutrinos that become active at ~10^{13}–10^{14} GeV. Together with a somewhat enhanced quartic coupling arising by a Higgs portal interaction to a dark matter sector, we can obtain a Higgs boson composed of neutrinos. Furthermore, this is a “next-to-minimal” dynamical electroweak symmetry breaking scheme.
Fat jets for a light higgs boson.
Plehn, Tilman; Salam, Gavin P; Spannowsky, Michael
2010-03-19
At the LHC associated top quark and Higgs boson production with a Higgs boson decay to bottom quarks has long been a heavily disputed search channel. Recently, it has been found not to be viable. We show how it can be observed by tagging massive Higgs bosons and top jets. For this purpose we construct boosted top and Higgs taggers for standard-model processes in a complex QCD environment.
Higgs boson production with heavy quarks at hadron colliders
NASA Astrophysics Data System (ADS)
Jackson, Christopher B.
2005-11-01
One of the remaining puzzles in particle physics is the origin of electroweak symmetry breaking. In the Standard Model (SM), a single doublet of complex scalar fields is responsible for breaking the SU(2) L x U(1)Y gauge symmetry thus giving mass to the electroweak gauge bosons via the Higgs mechanism and to the fermions via Yukawa couplings. The remnant of the process is a vet to he discovered scalar particle, the Higgs boson (h). However, current and future experiments at hadron colliders hold great promise. Of particular interest at hadron colliders is the production of a Higgs boson in association with a pair of heavy quarks, pp¯(pp) → QQ¯h, where Q can be either a top or a bottom quark. Indeed, the production of a Higgs boson with a pair of top quarks provides a very distinctive signal in hadronic collisions where background processes are formidable, and it will be instrumental in the discovery of a Higgs boson below about 130 GeV at the LHC. On the other hand, the production of a Higgs boson with bottom quarks can be strongly enhanced in models of new physics beyond the SM, e.g. supersymmetric models. If this is the case, bb¯h production will play a crucial role at the Tevatron where it could provide the first signal of new physics. Given the prominent role that Higgs production with heavy quarks can play at hadron colliders, it becomes imperative to have precise theoretical predictions for total and differential cross sections. In this dissertation, we outline and present detailed results for the next-to-leading order (NLO) calculation of the Quantum Chromodynamic (QCD) corrections to QQ¯h production at both the Tevatron and the LHC. This calculation involves several difficult issues due to the three massive particles in the final state, a situation which is at the frontier of radiative correction calculations in quantum field theory. We detail the novel techniques developed to deal with these challenges. The calculation of pp¯(pp) → bb¯h at NLO in
Haydock's recursive solution of self-adjoint problems. Discrete spectrum
NASA Astrophysics Data System (ADS)
Moroz, Alexander
2014-12-01
Haydock's recursive solution is shown to underline a number of different concepts such as (i) quasi-exactly solvable models, (ii) exactly solvable models, (iii) three-term recurrence solutions based on Schweber's quantization criterion in Hilbert spaces of entire analytic functions, and (iv) a discrete quantum mechanics of Odake and Sasaki. A recurrent theme of Haydock's recursive solution is that the spectral properties of any self-adjoint problem can be mapped onto a corresponding sequence of polynomials {pn(E) } in energy variable E. The polynomials {pn(E) } are orthonormal with respect to the density of states n0(E) and energy eigenstate | E > is the generating function of {pn(E) } . The generality of Haydock's recursive solution enables one to see the different concepts from a unified perspective and mutually benefiting from each other. Some results obtained within the particular framework of any of (i) to (iv) may have much broader significance.
Self-adjoint integral operator for bounded nonlocal transport
NASA Astrophysics Data System (ADS)
Maggs, J. E.; Morales, G. J.
2016-11-01
An integral operator is developed to describe nonlocal transport in a one-dimensional system bounded on both ends by material walls. The "jump" distributions associated with nonlocal transport are taken to be Lévy α -stable distributions, which become naturally truncated by the bounding walls. The truncation process results in the operator containing a self-consistent, convective inward transport term (pinch). The properties of the integral operator as functions of the Lévy distribution parameter set [α ,γ ] and the wall conductivity are presented. The integral operator continuously recovers the features of local transport when α =2 . The self-adjoint formulation allows for an accurate description of spatial variation in the Lévy parameters in the nonlocal system. Spatial variation in the Lévy parameters is shown to result in internally generated flows. Examples of cold-pulse propagation in nonlocal systems illustrate the capabilities of the methodology.
Self-adjoint integral operator for bounded nonlocal transport.
Maggs, J E; Morales, G J
2016-11-01
An integral operator is developed to describe nonlocal transport in a one-dimensional system bounded on both ends by material walls. The "jump" distributions associated with nonlocal transport are taken to be Lévy α-stable distributions, which become naturally truncated by the bounding walls. The truncation process results in the operator containing a self-consistent, convective inward transport term (pinch). The properties of the integral operator as functions of the Lévy distribution parameter set [α,γ] and the wall conductivity are presented. The integral operator continuously recovers the features of local transport when α=2. The self-adjoint formulation allows for an accurate description of spatial variation in the Lévy parameters in the nonlocal system. Spatial variation in the Lévy parameters is shown to result in internally generated flows. Examples of cold-pulse propagation in nonlocal systems illustrate the capabilities of the methodology.
NASA Astrophysics Data System (ADS)
Fernández-López, Sheila; Carrera, Jesús; Ledo, Juanjo; Queralt, Pilar; Luquot, Linda; Martínez, Laura; Bellmunt, Fabián
2016-04-01
Seawater intrusion in aquifers is a complex phenomenon that can be characterized with the help of electric resistivity tomography (ERT) because of the low resistivity of seawater, which underlies the freshwater floating on top. The problem is complex because of the need for joint inversion of electrical and hydraulic (density dependent flow) data. Here we present an adjoint-state algorithm to treat electrical data. This method is a common technique to obtain derivatives of an objective function, depending on potentials with respect to model parameters. The main advantages of it are its simplicity in stationary problems and the reduction of computational cost respect others methodologies. The relationship between the concentration of chlorides and the resistivity values of the field is well known. Also, these resistivities are related to the values of potentials measured using ERT. Taking this into account, it will be possible to define the different resistivities zones from the field data of potential distribution using the basis of inverse problem. In this case, the studied zone is situated in Argentona (Baix Maresme, Catalonia), where the values of chlorides obtained in some wells of the zone are too high. The adjoint-state method will be used to invert the measured data using a new finite element code in C ++ language developed in an open-source framework called Kratos. Finally, the information obtained numerically with our code will be checked with the information obtained with other codes.
Perturbative unitarity bounds in composite two-Higgs doublet models
NASA Astrophysics Data System (ADS)
De Curtis, Stefania; Moretti, Stefano; Yagyu, Kei; Yildirim, Emine
2016-09-01
We study bounds from perturbative unitarity in a composite two-Higgs doublet model (C2HDM) based on the spontaneous breakdown of a global symmetry S O (6 )→S O (4 )×S O (2 ) at the compositeness scale f . The eight pseudo-Nambu-Goldstone bosons (pNGBs) emerging from such a dynamics are identified as two isospin doublet Higgs fields. We calculate the S -wave amplitude for all possible two-to-two-body elastic (pseudo)scalar boson scatterings at energy scales √{s } reachable at the Large Hadron Collider (LHC) and beyond it, including the longitudinal components of weak gauge boson states as the corresponding pNGB states. In our calculation, the Higgs potential is assumed to have the same form as that in the elementary two-Higgs doublet model (E2HDM) with a discrete Z2 symmetry, which is expected to be generated at the one-loop level via the Coleman-Weinberg mechanism. We find that the S -wave amplitude matrix can be block-diagonalized with maximally 2 ×2 submatrices in a way similar to the E2HDM case as long as we only keep the contributions from O (ξ s ) and O (ξ0s0) in the amplitudes, where ξ =vSM2/f2 and vSM≃246 GeV , which is an appropriate approximation for our analysis. By requiring the C2HDM to satisfy perturbative unitarity at energies reachable by the LHC, we derive bounds on its parameters such as ξ and the masses of extra Higgs bosons present in the scenario alongside the Standard Model-like Higgs state discovered in 2012.
Radion and Higgs masses in gauge-Higgs unification
Sakamura, Yutaka
2011-02-01
We evaluate the radion and Higgs masses in the gauge-Higgs unification models on the warped geometry, in which the modulus is stabilized by the Casimir energy. We analyze the one-loop effective potential and clarify the dependences of those masses on the Wilson line phase {theta}{sub H}. The radion mass varies 1-30 GeV for 0.06{<=}sin{theta}{sub H{<=}}0.3, while the Higgs mass is 150-200 GeV and depends on {theta}{sub H} only logarithmically. The radion couplings to the standard model particles are sensitive to the warp factor, and are too small to detect at colliders in the region where the five-dimensional description is valid.
Optimizing spectral wave estimates with adjoint-based sensitivity maps
NASA Astrophysics Data System (ADS)
Orzech, Mark; Veeramony, Jay; Flampouris, Stylianos
2014-04-01
A discrete numerical adjoint has recently been developed for the stochastic wave model SWAN. In the present study, this adjoint code is used to construct spectral sensitivity maps for two nearshore domains. The maps display the correlations of spectral energy levels throughout the domain with the observed energy levels at a selected location or region of interest (LOI/ROI), providing a full spectrum of values at all locations in the domain. We investigate the effectiveness of sensitivity maps based on significant wave height ( H s ) in determining alternate offshore instrument deployment sites when a chosen nearshore location or region is inaccessible. Wave and bathymetry datasets are employed from one shallower, small-scale domain (Duck, NC) and one deeper, larger-scale domain (San Diego, CA). The effects of seasonal changes in wave climate, errors in bathymetry, and multiple assimilation points on sensitivity map shapes and model performance are investigated. Model accuracy is evaluated by comparing spectral statistics as well as with an RMS skill score, which estimates a mean model-data error across all spectral bins. Results indicate that data assimilation from identified high-sensitivity alternate locations consistently improves model performance at nearshore LOIs, while assimilation from low-sensitivity locations results in lesser or no improvement. Use of sub-sampled or alongshore-averaged bathymetry has a domain-specific effect on model performance when assimilating from a high-sensitivity alternate location. When multiple alternate assimilation locations are used from areas of lower sensitivity, model performance may be worse than with a single, high-sensitivity assimilation point.
NASA Technical Reports Server (NTRS)
Arian, Eyal; Salas, Manuel D.
1997-01-01
We derive the adjoint equations for problems in aerodynamic optimization which are improperly considered as "inadmissible." For example, a cost functional which depends on the density, rather than on the pressure, is considered "inadmissible" for an optimization problem governed by the Euler equations. We show that for such problems additional terms should be included in the Lagrangian functional when deriving the adjoint equations. These terms are obtained from the restriction of the interior PDE to the control surface. Demonstrations of the explicit derivation of the adjoint equations for "inadmissible" cost functionals are given for the potential, Euler, and Navier-Stokes equations.
NASA Technical Reports Server (NTRS)
Nguyen, Nhan T.; Hornby, Gregory; Ishihara, Abe
2013-01-01
This paper describes two methods of trajectory optimization to obtain an optimal trajectory of minimum-fuel- to-climb for an aircraft. The first method is based on the adjoint method, and the second method is based on a direct trajectory optimization method using a Chebyshev polynomial approximation and cubic spine approximation. The approximate optimal trajectory will be compared with the adjoint-based optimal trajectory which is considered as the true optimal solution of the trajectory optimization problem. The adjoint-based optimization problem leads to a singular optimal control solution which results in a bang-singular-bang optimal control.
Adjoint-Based Methods for Estimating CO2 Sources and Sinks from Atmospheric Concentration Data
NASA Technical Reports Server (NTRS)
Andrews, Arlyn E.
2003-01-01
Work to develop adjoint-based methods for estimating CO2 sources and sinks from atmospheric concentration data was initiated in preparation for last year's summer institute on Carbon Data Assimilation (CDAS) at the National Center for Atmospheric Research in Boulder, CO. The workshop exercises used the GSFC Parameterized Chemistry and Transport Model and its adjoint. Since the workshop, a number of simulations have been run to evaluate the performance of the model adjoint. Results from these simulations will be presented, along with an outline of challenges associated with incorporating a variety of disparate data sources, from sparse, but highly precise, surface in situ observations to less accurate, global future satellite observations.
New spectra in the HEIDI Higgs models
NASA Astrophysics Data System (ADS)
van der Bij, J. J.; Puliçe, B.
2011-12-01
We study the so-called HEIDI models, which are renormalizable extensions of the standard model with a higher-dimensional scalar singlet field. As an additional parameter we consider a higher-dimensional mixing mass parameter. This leads to enriched possibilities compared to a previous study. We find effective spectral densities of the Higgs propagator, consisting of one, two or no particle peaks, together with a continuum. We compare with the LEP-2 data and determine for which range of the model parameters the data can be described. Assuming two peaks to be present we find for the new mass scale ν≈56±12 GeV, largely independent of the dimension. In the limiting case of d→6 and two peaks we find a higher-dimensional coupling constant α=0.70±0.18, indicative of strong interactions among the higher-dimensional fields. This Higgs might escape discovery at the LHC. That would provide a strong physics case for building a new lepton collider.
Roles of a 45-plet of Higgs particles in SU(5) grand unified theory
NASA Astrophysics Data System (ADS)
Hayashi, Hirofumi; Murayama, Akihiro; Hayashi, Mitsuo J.
1982-09-01
In the light of the notable role played by a 45-plet of Higgs particles in SU(5) grand unified theory, a harmless axion containing a component from a Higgs 45-plet is derived following the Dine-Fischler-Srednicki scheme in the SU(5)×U(1)PQ model (PQ refers to Peccei and Quinn). The breaking of U(1)PQ through instanton effects into Z6 gives a useful relation between vacuum expectation values of 45 and 5, Higgs fields. An estimation of the cosmological baryon-to-entropy ratio is also presented, and is consistent with the present observations.
Higgs-radion phenomenology in stabilized RS models
NASA Astrophysics Data System (ADS)
Boos, Eduard; Bunichev, Viacheslav; Keizerov, Sergey; Perfilov, Maxim; Rakhmetov, Eduard; Smolyakov, Mikhail; Svirina, Kseniia; Volobuev, Igor
2016-10-01
An important general prediction of stabilized brane world models is the existence of a bulk scalar radion field, whose lowest Kaluza-Klein (KK) mode is the scalar particle called the radion. This field comes from the fluctuations of the metric in the extra dimension and the radion mass can be smaller than that of all the massive KK modes of the other particles propagating in the multidimensional bulk. Due to its origin, the radion and its KK tower couple to the trace of the energy-momentum tensor of the Standard Model. These fields have the same quantum numbers as the neutral Higgs field and can mix with the latter, if they are coupled. We present a short review of some aspects of Higgs-radion phenomenology in stabilized brane-world models. In particular, we discuss the possibility of explaining the 750 GeV excess by the production of a radion-dominated state.
Non-minimal Higgs inflation and frame dependence in cosmology
Steinwachs, Christian F.; Kamenshchik, Alexander Yu.
2013-02-21
We investigate a very general class of cosmological models with scalar fields non-minimally coupled to gravity. A particular representative in this class is given by the non-minimal Higgs inflation model in which the Standard Model Higgs boson and the inflaton are described by one and the same scalar particle. While the predictions of the non-minimal Higgs inflation scenario come numerically remarkably close to the recently discovered mass of the Higgs boson, there remains a conceptual problem in this model that is associated with the choice of the cosmological frame. While the classical theory is independent of this choice, we find by an explicit calculation that already the first quantum corrections induce a frame dependence. We give a geometrical explanation of this frame dependence by embedding it into a more general field theoretical context. From this analysis, some conceptional points in the long lasting cosmological debate: 'Jordan frame vs. Einstein frame' become more transparent and in principle can be resolved in a natural way.
Vacuum topology of the two Higgs doublet model
NASA Astrophysics Data System (ADS)
Battye, Richard A.; Brawn, Gary D.; Pilaftsis, Apostolos
2011-08-01
We perform a systematic study of generic accidental Higgs-family and CP symmetries that could occur in the two-Higgs-doublet-model potential, based on a Majorana scalar-field formalism which realizes a subgroup of {text{GL}}left( {8,mathbb{C}} right) . We derive the general conditions of convexity and stability of the scalar potential and present analytical solutions for two non-zero neutral vacuum expectation values of the Higgs doublets for a typical set of six symmetries, in terms of the gauge-invariant parameters of the theory. By means of a homotopy-group analysis, we identify the topological defects associated with the spontaneous symmetry breaking of each symmetry, as well as the massless Goldstone bosons emerging from the breaking of the continuous symmetries. We find the existence of domain walls from the breaking of Z2, CP1 and CP2 discrete symmetries, vortices in models with broken U(1)PQ and CP3 symmetries and a global monopole in the SO(3)HF-broken model. The spatial profile of the topological defect solutions is studied in detail, as functions of the potential parameters of the two-Higgs doublet model. The application of our Majorana scalar-field formalism in studying more general scalar potentials that are not constrained by the U(1)Y hypercharge symmetry is discussed. In particular, the same formalism may be used to properly identify seven additional symmetries that may take place in a U(1)Y-invariant scalar potential.
Margaroli, Fabrizio
2014-09-15
We show the latest results from the CDF and D0 collaborations on the study of the Higgs boson, stemming from the analysis of the entire Tevatron Run\\,II dataset. Combining the results of many individual analyses, most of which use the full data set available, an excess with a significance of approximately three standard deviations with respect to the Standard Model hypothesis is observed at a Higgs boson mass of 125\\,GeV/$c^2$. The Tevatron unique environment allows in addition to study for the first time the spin-parity hypothesis of the Higgs boson in events where it decays to quarks. Within the current experimental uncertainties, the newly discovered boson behaves as expected by the SM in the fermionic sector.
Higgs triplets and limits from precision measurements
Chen, Mu-Chun; Dawson, Sally; Krupovnickas, Tadas; /Brookhaven
2006-04-01
In this letter, they present the results on a global fit to precision electroweak data in a Higgs triplet model. In models with a triplet Higgs boson, a consistent renormalization scheme differs from that of the Standard Model and the global fit shows that a light Higgs boson with mass of 100-200 GeV is preferred. Triplet Higgs bosons arise in many extensions of the Standard Model, including the left-right model and the Little Higgs models. The result demonstrates the importance of the scalar loops when there is a large mass splitting between the heavy scalars. It also indicates the significance of the global fit.
Three phases in the three-dimensional Abelian-Higgs model with nonlocal gauge interactions
Takashima, Shunsuke; Ichinose, Ikuo; Matsui, Tetsuo; Sakakibara, Kazuhiko
2006-08-15
We study the phase structure of the three-dimensional (3D) nonlocal compact U(1) lattice gauge theory coupled with a Higgs field by Monte Carlo simulations. The nonlocal interactions among gauge variables are along the temporal direction and mimic the effect of local coupling to massless particles. In contrast to the 3D local Abelian-Higgs model having only the confinement phase, the present model exhibits the confinement, Higgs, and Coulomb phases separated by three second-order transition lines emanating from a triple point. This result is relevant not only to the 3D massless QED coupled with a Higgs field but also to electron fractionalization phenomena in strongly correlated electron systems like the high-T{sub c} superconductors and the fractional quantum Hall effect.
Topics in little Higgs physics
NASA Astrophysics Data System (ADS)
Chang, Spencer
The Standard Model is the currently accepted model of elementary particle interactions as determined by many years of particle physics experiments. It is both highly predictive and successful in its predictions, which is one of the great achievements of the last half century of science. However, there are indications that the Standard Model is incomplete with the main evidence being the so called hierarchy problem. In general terms, the hierarchy problem suggests that the parameters of the Standard Model have to be severely fine tuned in order to describe the real world. Motivated by the naturalness issues the hierarchy problem provokes, many theories of beyond the Standard Model physics have been proposed that alleviate the fine tuning. Continuing this approach, recently a new scenario called "Little Higgs" theories has been suggested as a viable alternative to the Standard Model, which has some novel features compared to the other competitive theories. The fact that these Little Higgs models may describe the real world is interesting and motivates their study. In the first chapter, an introduction describing in elementary terms what the hierarchy problem is and how Little Higgs theories are a solution to this problem is presented. After this short introduction, two topics in Little Higgs theories are analyzed. The first subject is determining if Little Higgs theories are consistent with the precision experiments performed to date. This is covered in chapters two and three, where two different Little Higgs models with approximate custodial SU(2) symmetry are presented. This symmetry increases the range of parameter space where these Little Higgs theories are both consistent with precision tests and are natural under the sense of the hierarchy problem. Thus, these theories are viable candidates for beyond the Standard Model physics. The fourth chapter is on the second subject, which is analyzing the constraints that unitarity places upon the Little Higgs theories
Inversion of tsunami sources by the adjoint method in the presence of observational and model errors
NASA Astrophysics Data System (ADS)
Pires, C.; Miranda, P. M. A.
2003-04-01
The adjoint method is applied to the inversion of tsumani sources from tide-gauge observations in both idealized and realistic setups, with emphasis on the effects of observational, bathymetric and other model errors in the quality of the inversion. The method is developed in a way that allows for the direct optimization of seismic focal parameters, in the case of seismic tsunamis, through a 4-step inversion procedure that can be fully automated, consisting in (i) source area delimitation, by adjoint backward ray-tracing, (ii) adjoint optimization of the initial sea state, from a vanishing first-guess, (iii) non-linear adjustment of the fault model and (iv) final adjoint optimization in the fault parameter space. The methodology is systematically tested with synthetic data, showing its flexibility and robustness in the presence of significant amounts of error.
Adjoint-Based Algorithms for Adaptation and Design Optimizations on Unstructured Grids
NASA Technical Reports Server (NTRS)
Nielsen, Eric J.
2006-01-01
Schemes based on discrete adjoint algorithms present several exciting opportunities for significantly advancing the current state of the art in computational fluid dynamics. Such methods provide an extremely efficient means for obtaining discretely consistent sensitivity information for hundreds of design variables, opening the door to rigorous, automated design optimization of complex aerospace configuration using the Navier-Stokes equation. Moreover, the discrete adjoint formulation provides a mathematically rigorous foundation for mesh adaptation and systematic reduction of spatial discretization error. Error estimates are also an inherent by-product of an adjoint-based approach, valuable information that is virtually non-existent in today's large-scale CFD simulations. An overview of the adjoint-based algorithm work at NASA Langley Research Center is presented, with examples demonstrating the potential impact on complex computational problems related to design optimization as well as mesh adaptation.
Application of Adjoint Methodology in Various Aspects of Sonic Boom Design
NASA Technical Reports Server (NTRS)
Rallabhandi, Sriram K.
2014-01-01
One of the advances in computational design has been the development of adjoint methods allowing efficient calculation of sensitivities in gradient-based shape optimization. This paper discusses two new applications of adjoint methodology that have been developed to aid in sonic boom mitigation exercises. In the first, equivalent area targets are generated using adjoint sensitivities of selected boom metrics. These targets may then be used to drive the vehicle shape during optimization. The second application is the computation of adjoint sensitivities of boom metrics on the ground with respect to parameters such as flight conditions, propagation sampling rate, and selected inputs to the propagation algorithms. These sensitivities enable the designer to make more informed selections of flight conditions at which the chosen cost functionals are less sensitive.
Discrete Adjoint-Based Design Optimization of Unsteady Turbulent Flows on Dynamic Unstructured Grids
NASA Technical Reports Server (NTRS)
Nielsen, Eric J.; Diskin, Boris; Yamaleev, Nail K.
2009-01-01
An adjoint-based methodology for design optimization of unsteady turbulent flows on dynamic unstructured grids is described. The implementation relies on an existing unsteady three-dimensional unstructured grid solver capable of dynamic mesh simulations and discrete adjoint capabilities previously developed for steady flows. The discrete equations for the primal and adjoint systems are presented for the backward-difference family of time-integration schemes on both static and dynamic grids. The consistency of sensitivity derivatives is established via comparisons with complex-variable computations. The current work is believed to be the first verified implementation of an adjoint-based optimization methodology for the true time-dependent formulation of the Navier-Stokes equations in a practical computational code. Large-scale shape optimizations are demonstrated for turbulent flows over a tiltrotor geometry and a simulated aeroelastic motion of a fighter jet.
Almost commuting self-adjoint matrices: The real and self-dual cases
NASA Astrophysics Data System (ADS)
Loring, Terry A.; Sørensen, Adam P. W.
2016-08-01
We show that a pair of almost commuting self-adjoint, symmetric matrices is close to a pair of commuting self-adjoint, symmetric matrices (in a uniform way). Moreover, we prove that the same holds with self-dual in place of symmetric and also for paths of self-adjoint matrices. Since a symmetric, self-adjoint matrix is real, we get a real version of Huaxin Lin’s famous theorem on almost commuting matrices. Similarly, the self-dual case gives a version for matrices over the quaternions. To prove these results, we develop a theory of semiprojectivity for real C*-algebras and also examine various definitions of low-rank for real C*-algebras.
Phenomenology of the Higgs effective Lagrangian via F eynR ules
NASA Astrophysics Data System (ADS)
Alloul, Adam; Fuks, Benjamin; Sanz, Verónica
2014-04-01
The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of F eynR ules and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of F eynR ules capable to generate model files that can be understood by the M adG raph 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-Higgs production. We finally study contact interactions of gauge and Higgs bosons to fermions.
NASA Astrophysics Data System (ADS)
Low, Ian; Schwaller, Pedro; Shaughnessy, Gabe; Wagner, Carlos E. M.
2012-01-01
Current limits from the Large Hadron Collider exclude a standard model-like Higgs mass above 150 GeV, by placing an upper bound on the Higgs production rate. We emphasize that, alternatively, the limit could be interpreted as a lower bound on the total decay width of the Higgs boson. If the invisible decay width of the Higgs is of the same order as the visible decay width, a heavy Higgs boson could be consistent with null results from current searches. We propose a method to infer the invisible decay of the Higgs by using the width of the measured h→ZZ→4ℓ line shape, and study the effect on the width extraction due to a reduced signal strength. Assuming the invisible decay product is the dark matter, we show that minimal models are tightly constrained by limits from Higgs searches at the LHC and direct detection experiments of dark matter, unless the relic density constraint is relaxed.
Adjoint Algorithm for CAD-Based Shape Optimization Using a Cartesian Method
NASA Technical Reports Server (NTRS)
Nemec, Marian; Aftosmis, Michael J.
2004-01-01
Adjoint solutions of the governing flow equations are becoming increasingly important for the development of efficient analysis and optimization algorithms. A well-known use of the adjoint method is gradient-based shape optimization. Given an objective function that defines some measure of performance, such as the lift and drag functionals, its gradient is computed at a cost that is essentially independent of the number of design variables (geometric parameters that control the shape). More recently, emerging adjoint applications focus on the analysis problem, where the adjoint solution is used to drive mesh adaptation, as well as to provide estimates of functional error bounds and corrections. The attractive feature of this approach is that the mesh-adaptation procedure targets a specific functional, thereby localizing the mesh refinement and reducing computational cost. Our focus is on the development of adjoint-based optimization techniques for a Cartesian method with embedded boundaries.12 In contrast t o implementations on structured and unstructured grids, Cartesian methods decouple the surface discretization from the volume mesh. This feature makes Cartesian methods well suited for the automated analysis of complex geometry problems, and consequently a promising approach to aerodynamic optimization. Melvin et developed an adjoint formulation for the TRANAIR code, which is based on the full-potential equation with viscous corrections. More recently, Dadone and Grossman presented an adjoint formulation for the Euler equations. In both approaches, a boundary condition is introduced to approximate the effects of the evolving surface shape that results in accurate gradient computation. Central to automated shape optimization algorithms is the issue of geometry modeling and control. The need to optimize complex, "real-life" geometry provides a strong incentive for the use of parametric-CAD systems within the optimization procedure. In previous work, we presented
Preliminary Results from the Application of Automated Adjoint Code Generation to CFL3D
NASA Technical Reports Server (NTRS)
Carle, Alan; Fagan, Mike; Green, Lawrence L.
1998-01-01
This report describes preliminary results obtained using an automated adjoint code generator for Fortran to augment a widely-used computational fluid dynamics flow solver to compute derivatives. These preliminary results with this augmented code suggest that, even in its infancy, the automated adjoint code generator can accurately and efficiently deliver derivatives for use in transonic Euler-based aerodynamic shape optimization problems with hundreds to thousands of independent design variables.
NASA Astrophysics Data System (ADS)
Smith, J. A.; Peter, D. B.; Tromp, J.; Komatitsch, D.; Lefebvre, M. P.
2015-12-01
We present both SPECFEM3D_Cartesian and SPECFEM3D_GLOBE open-source codes, representing high-performance numerical wave solvers simulating seismic wave propagation for local-, regional-, and global-scale application. These codes are suitable for both forward propagation in complex media and tomographic imaging. Both solvers compute highly accurate seismic wave fields using the continuous Galerkin spectral-element method on unstructured meshes. Lateral variations in compressional- and shear-wave speeds, density, as well as 3D attenuation Q models, topography and fluid-solid coupling are all readily included in both codes. For global simulations, effects due to rotation, ellipticity, the oceans, 3D crustal models, and self-gravitation are additionally included. Both packages provide forward and adjoint functionality suitable for adjoint tomography on high-performance computing architectures. We highlight the most recent release of the global version which includes improved performance, simultaneous MPI runs, OpenCL and CUDA support via an automatic source-to-source transformation library (BOAST), parallel I/O readers and writers for databases using ADIOS and seismograms using the recently developed Adaptable Seismic Data Format (ASDF) with built-in provenance. This makes our spectral-element solvers current state-of-the-art, open-source community codes for high-performance seismic wave propagation on arbitrarily complex 3D models. Together with these solvers, we provide full-waveform inversion tools to image the Earth's interior at unprecedented resolution.
Radius stabilization and dark matter with a bulk Higgs in warped extra dimension
Ahmed, A.; Grzadkowski, B.; Gunion, J. F.; ...
2015-01-01
In this study, we employ an SU(2) bulk Higgs doublet as the stabilization field in the Randall–Sundrum model with appropriate bulk and brane-localized potentials. The gauge hierarchy problem can be solved for an exponentially IR-localized Higgs background field with mild values of fundamental parameters of the 5D theory. We consider an IR–UV–IR background geometry with the 5D SM fields in the bulk such that all the fields have even and odd towers of KK-modes. The zero-mode 4D effective theory contains all the SM fields plus a stable scalar, which serves as a dark matter candidate.
Double Higgs production in the Two Higgs Doublet Model at the linear collider
Arhrib, Abdesslam; Benbrik, Rachid; Chiang, C.-W.
2008-04-21
We study double Higgs-strahlung production at the future Linear Collider in the framework of the Two Higgs Doublet Models through the following channels: e{sup +}e{sup -}{yields}{phi}{sub i}{phi}{sub j}Z, {phi}{sub i} = h deg., H deg., A deg. All these processes are sensitive to triple Higgs couplings. Hence observations of them provide information on the triple Higgs couplings that help reconstructing the scalar potential. We discuss also the double Higgs-strahlung e{sup +}e{sup -}{yields}h deg. h deg. Z in the decoupling limit where h deg. mimics the SM Higgs boson.
Higgs production as a probe of chameleon dark energy
Brax, Philippe; Burrage, Clare; Davis, Anne-Christine; Seery, David; Weltman, Amanda
2010-05-15
In this paper we study various particle physics effects of a light, scalar dark energy field with chameleonlike couplings to matter. We show that a chameleon model with only matter couplings will induce a coupling to photons. In doing so, we derive the first microphysical realization of a chameleonic dark energy model coupled to the electromagnetic field strength. This analysis provides additional motivation for current and near-future tests of axionlike and chameleon particles. We find a new bound on the coupling strength of chameleons in uniformly coupled models. We also study the effect of chameleon fields on Higgs production, which is relevant for hadron colliders. These are expected to manufacture Higgs particles through weak boson fusion, or associated production with a Z or W{sup {+-}.} We show that, like the Tevatron, the LHC will not be able to rule out or observe chameleons through this mechanism, because gauge invariance of the low energy Lagrangian suppresses the corrections that may arise.
A Generalized Adjoint Approach for Quantifying Reflector Assembly Discontinuity Factor Uncertainties
Yankov, Artem; Collins, Benjamin; Jessee, Matthew Anderson; Downar, Thomas
2012-01-01
Sensitivity-based uncertainty analysis of assembly discontinuity factors (ADFs) can be readily performed using adjoint methods for infinite lattice models. However, there is currently no adjoint-based methodology to obtain uncertainties for ADFs along an interface between a fuel and reflector region. To accommodate leakage effects in a reflector region, a 1D approximation is usually made in order to obtain the homogeneous interface flux required to calculate the ADF. Within this 1D framework an adjoint-based method is proposed that is capable of efficiently calculating ADF uncertainties. In the proposed method the sandwich rule is utilized to relate the covariance of the input parameters of 1D diffusion theory in the reflector region to the covariance of the interface ADFs. The input parameters covariance matrix can be readily obtained using sampling-based codes such as XSUSA or adjoint-based codes such as TSUNAMI. The sensitivity matrix is constructed using a fixed-source adjoint approach for inputs characterizing the reflector region. An analytic approach is then used to determine the sensitivity of the ADFs to fuel parameters using the neutron balance equation. A stochastic approach is used to validate the proposed adjoint-based method.
The adjoint neutron transport equation and the statistical approach for its solution
NASA Astrophysics Data System (ADS)
Saracco, P.; Dulla, S.; Ravetto, P.
2016-11-01
The adjoint equation was introduced in the early days of neutron transport and its solution, the neutron importance, has been used for several applications in neutronics. The work presents at first a critical review of the adjoint neutron transport equation. Afterwards, the adjont model is constructed for a reference physical situation, for which an analytical approach is viable, i.e. an infinite homogeneous scattering medium. This problem leads to an equation that is the adjoint of the slowing-down equation, which is well known in nuclear reactor physics. A general closed-form analytical solution to such adjoint equation is obtained by a procedure that can be used also to derive the classical Placzek functions. This solution constitutes a benchmark for any statistical or numerical approach to the adjoint equation. A sampling technique to evaluate the adjoint flux for the transport equation is then proposed and physically interpreted as a transport model for pseudo-particles. This can be done by introducing appropriate kernels describing the transfer of the pseudo-particles in the phase space. This technique allows estimating the importance function by a standard Monte Carlo approach. The sampling scheme is validated by comparison with the analytical results previously obtained.
Cyclic cosmology, conformal symmetry and the metastability of the Higgs
NASA Astrophysics Data System (ADS)
Bars, Itzhak; Steinhardt, Paul J.; Turok, Neil
2013-10-01
Recent measurements at the LHC suggest that the current Higgs vacuum could be metastable with a modest barrier (height ( GeV)4) separating it from a ground state with negative vacuum density of order the Planck scale. We note that metastability is problematic for standard bang cosmology but is essential for cyclic cosmology in order to end one cycle, bounce, and begin the next. In this Letter, motivated by the approximate scaling symmetry of the standard model of particle physics and the primordial large-scale structure of the universe, we use our recent formulation of the Weyl-invariant version of the standard model coupled to gravity to track the evolution of the Higgs in a regularly bouncing cosmology. We find a band of solutions in which the Higgs field escapes from the metastable phase during each big crunch, passes through the bang into an expanding phase, and returns to the metastable vacuum, cycle after cycle after cycle. We show that, due to the effect of the Higgs, the infinitely cycling universe is geodesically complete, in contrast to inflation.
Quantum corrections in Higgs inflation: the real scalar case
George, Damien P.; Mooij, Sander; Postma, Marieke E-mail: sander.mooij@ing.uchile.cl
2014-02-01
We present a critical discussion of quantum corrections, renormalisation, and the computation of the beta functions and the effective potential in Higgs inflation. In contrast with claims in the literature, we find no evidence for a disagreement between the Jordan and Einstein frames, even at the quantum level. For clarity of discussion we concentrate on the case of a real scalar Higgs. We first review the classical calculation and then discuss the back reaction of gravity. We compute the beta functions for the Higgs quartic coupling and non-minimal coupling constant. Here, the mid-field regime is non-renormalisable, but we are able to give an upper bound on the 1-loop corrections to the effective potential. We show that, in computing the effective potential, the Jordan and Einstein frames are compatible if all mass scales are transformed between the two frames. As such, it is consistent to take a constant cutoff in either the Jordan or Einstein frame, and both prescriptions yield the same result for the effective potential. Our results are extended to the case of a complex scalar Higgs.
Finn, John M.
2015-03-01
Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a 'special divergence-free' property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Ref. [11], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Ref. [35], appears to work very well.
Big Data Challenges in Global Seismic 'Adjoint Tomography' (Invited)
NASA Astrophysics Data System (ADS)
Tromp, J.; Bozdag, E.; Krischer, L.; Lefebvre, M.; Lei, W.; Smith, J.
2013-12-01
The challenge of imaging Earth's interior on a global scale is closely linked to the challenge of handling large data sets. The related iterative workflow involves five distinct phases, namely, 1) data gathering and culling, 2) synthetic seismogram calculations, 3) pre-processing (time-series analysis and time-window selection), 4) data assimilation and adjoint calculations, 5) post-processing (pre-conditioning, regularization, model update). In order to implement this workflow on modern high-performance computing systems, a new seismic data format is being developed. The Adaptable Seismic Data Format (ASDF) is designed to replace currently used data formats with a more flexible format that allows for fast parallel I/O. The metadata is divided into abstract categories, such as "source" and "receiver", along with provenance information for complete reproducibility. The structure of ASDF is designed keeping in mind three distinct applications: earthquake seismology, seismic interferometry, and exploration seismology. Existing time-series analysis tool kits, such as SAC and ObsPy, can be easily interfaced with ASDF so that seismologists can use robust, previously developed software packages. ASDF accommodates an automated, efficient workflow for global adjoint tomography. Manually managing the large number of simulations associated with the workflow can rapidly become a burden, especially with increasing numbers of earthquakes and stations. Therefore, it is of importance to investigate the possibility of automating the entire workflow. Scientific Workflow Management Software (SWfMS) allows users to execute workflows almost routinely. SWfMS provides additional advantages. In particular, it is possible to group independent simulations in a single job to fit the available computational resources. They also give a basic level of fault resilience as the workflow can be resumed at the correct state preceding a failure. Some of the best candidates for our particular workflow
Plumes, Hotspot & Slabs Imaged by Global Adjoint Tomography
NASA Astrophysics Data System (ADS)
Bozdag, E.; Lefebvre, M. P.; Lei, W.; Peter, D. B.; Smith, J. A.; Komatitsch, D.; Tromp, J.
2015-12-01
We present the "first generation" global adjoint tomography model based on 3D wave simulations, which is the result of 15 conjugate-gradient iterations with confined transverse isotropy to the upper mantle. Our starting model is the 3D mantle and crustal models S362ANI (Kustowski et al. 2008) and Crust2.0 (Bassin et al. 2000), respectively. We take into account the full nonlinearity of wave propagation in numerical simulations including attenuation (both in forward and adjoint simulations), topography/bathymetry, etc., using the GPU version of the SPECFEM3D_GLOBE package. We invert for crust and mantle together without crustal corrections to avoid any bias in mantle structure. We started with an initial selection of 253 global CMT events within the magnitude range 5.8 ≤ Mw ≤ 7.0 with numerical simulations having resolution down to 27 s combining 30-s body and 60-s surface waves. After the 12th iteration we increased the resolution to 17 s, including higher-frequency body waves as well as going down to 45 s in surface-wave measurements. We run 180-min seismograms and assimilate all minor- and major-arc body and surface waves. Our 15th iteration model update shows a tantalisingly enhanced image of the Tahiti plume as well as various other plumes and hotspots, such as Caroline, Galapagos, Yellowstone, Erebus, etc. Furthermore, we see clear improvements in slab resolution along the Hellenic and Japan Arcs, as well as subduction along the East of Scotia Plate, which does not exist in the initial model. Point-spread function tests (Fichtner & Trampert 2011) suggest that we are close to the resolution of continental-scale studies in our global inversions and able to confidently map features, for instance, at the scale of the Yellowstone hotspot. This is a clear consequence of our multi-scale smoothing strategy, in which we define our smoothing operator as a function of the approximate Hessian kernel and smooth our gradients less wherever we have good ray coverage
Scrutinizing the alignment limit in two-Higgs-doublet models: mh=125 GeV
NASA Astrophysics Data System (ADS)
Bernon, Jérémy; Gunion, John F.; Haber, Howard E.; Jiang, Yun; Kraml, Sabine
2015-10-01
In the alignment limit of a multidoublet Higgs sector, one of the Higgs mass eigenstates aligns with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider C P -conserving two-Higgs-doublet models (2HDMs) of Type I and Type II near the alignment limit in which the lighter of the two C P -even Higgs bosons, h , is the SM-like state observed at 125 GeV. In particular, we focus on the 2HDM parameter regime where the coupling of h to gauge bosons approaches that of the SM. We review the theoretical structure and analyze the phenomenological implications of the regime of the alignment limit without decoupling, in which the other Higgs scalar masses are not significantly larger than mh and thus do not decouple from the effective theory at the electroweak scale. For the numerical analysis, we perform scans of the 2HDM parameter space employing the software packages 2hdmc and lilith, taking into account all relevant pre-LHC constraints, the latest constraints from the measurements of the 125 GeV Higgs signal at the LHC, as well as the most recent limits coming from searches for heavy Higgs-like states. We contrast these results with the alignment limit achieved via the decoupling of heavier scalar states, where h is the only light Higgs scalar. Implications for Run 2 at the LHC, including expectations for observing the other scalar states, are also discussed.
Atomic quantum simulation of a three-dimensional U(1) gauge-Higgs model
NASA Astrophysics Data System (ADS)
Kuno, Yoshihito; Sakane, Shinya; Kasamatsu, Kenichi; Ichinose, Ikuo; Matsui, Tetsuo
2016-12-01
In this paper, we study theoretically atomic quantum simulations of a U(1) gauge-Higgs model on a three-dimensional (3D) spatial lattice by using an extended Bose-Hubbard model with intersite repulsions on a 3D optical lattice. Here, the phase and density fluctuations of the boson variable on each site of the optical lattice describe the vector potential and the electric field on each link of the gauge-model lattice, respectively. The target gauge model is different from the standard Wilson-type U(1) gauge-Higgs model because it has plaquette and Higgs interactions with asymmetric couplings in the space-time directions. Nevertheless, the corresponding quantum simulation is still important as it provides us with a platform to study unexplored time-dependent phenomena characteristic of each phase in the general gauge-Higgs models. To determine the phase diagram of the gauge-Higgs model at zero temperature, we perform Monte Carlo simulations of the corresponding 3+1-dimensional U(1) gauge-Higgs model, and obtain the confinement and Higgs phases. To investigate the dynamical properties of the gauge-Higgs model, we apply the Gross-Pitaevskii equations to the extended Bose-Hubbard model. We simulate the time evolution of an electric flux that initially is put on a straight line connecting two external point charges. We also calculate the potential energy between this pair of charges and obtain the string tension in the confinement phase. Finally, we propose a feasible experimental setup for the atomic simulations of this quantum gauge-Higgs model on the 3D optical lattice. These results may serve as theoretical guides for future experiments.
Fermiophobic Higgs boson and supersymmetry
NASA Astrophysics Data System (ADS)
Gabrielli, E.; Kannike, K.; Mele, B.; Racioppi, A.; Raidal, M.
2012-09-01
If a light Higgs boson with mass 125 GeV is fermiophobic, or partially fermiophobic, then the minimal supersymmetric standard model is excluded. The minimal supersymmetric fermiophobic Higgs scenario can naturally be formulated in the context of the next-to-minimal supersymmetric standard model (NMSSM) that admits Z3 discrete symmetries. In the fermiophobic NMSSM, the supersymmetry naturalness criteria are relaxed by a factor Ncyt4/g4˜25, removing the little hierarchy problem and allowing sparticle masses to be naturally of order 2-3 TeV. This scale motivates wino or Higgsino dark matter. The SUSY flavor and CP problems as well as the constraints on sparticle and Higgs boson masses from b→sγ, Bs→μμ and direct LHC searches are relaxed in the fermiophobic NMSSM. The price to pay is that a new, yet unknown, mechanism must be introduced to generate fermion masses. We show that in the fermiophobic NMSSM the radiative Higgs boson branchings to γγ, γZ can be modified compared to the fermiophobic and ordinary standard model predictions, and fit present collider data better. Suppression of dark matter scattering off nuclei explains the absence of signal in XENON100.
A practical discrete-adjoint method for high-fidelity compressible turbulence simulations
Vishnampet, Ramanathan; Bodony, Daniel J.; Freund, Jonathan B.
2015-03-15
Methods and computing hardware advances have enabled accurate predictions of complex compressible turbulence phenomena, such as the generation of jet noise that motivates the present effort. However, limited understanding of underlying physical mechanisms restricts the utility of such predictions since they do not, by themselves, indicate a route to design improvements. Gradient-based optimization using adjoints can circumvent the flow complexity to guide designs, though this is predicated on the availability of a sufficiently accurate solution of the forward and adjoint systems. These are challenging to obtain, since both the chaotic character of the turbulence and the typical use of discretizations near their resolution limits in order to efficiently represent its smaller scales will amplify any approximation errors made in the adjoint formulation. Formulating a practical exact adjoint that avoids such errors is especially challenging if it is to be compatible with state-of-the-art simulation methods used for the turbulent flow itself. Automatic differentiation (AD) can provide code to calculate a nominally exact adjoint, but existing general-purpose AD codes are inefficient to the point of being prohibitive for large-scale turbulence simulations. Here, we analyze the compressible flow equations as discretized using the same high-order workhorse methods used for many high-fidelity compressible turbulence simulations, and formulate a practical space–time discrete-adjoint method without changing the basic discretization. A key step is the definition of a particular discrete analog of the continuous norm that defines our cost functional; our selection leads directly to an efficient Runge–Kutta-like scheme, though it would be just first-order accurate if used outside the adjoint formulation for time integration, with finite-difference spatial operators for the adjoint system. Its computational cost only modestly exceeds that of the flow equations. We confirm that
A practical discrete-adjoint method for high-fidelity compressible turbulence simulations
NASA Astrophysics Data System (ADS)
Vishnampet, Ramanathan; Bodony, Daniel J.; Freund, Jonathan B.
2015-03-01
Methods and computing hardware advances have enabled accurate predictions of complex compressible turbulence phenomena, such as the generation of jet noise that motivates the present effort. However, limited understanding of underlying physical mechanisms restricts the utility of such predictions since they do not, by themselves, indicate a route to design improvements. Gradient-based optimization using adjoints can circumvent the flow complexity to guide designs, though this is predicated on the availability of a sufficiently accurate solution of the forward and adjoint systems. These are challenging to obtain, since both the chaotic character of the turbulence and the typical use of discretizations near their resolution limits in order to efficiently represent its smaller scales will amplify any approximation errors made in the adjoint formulation. Formulating a practical exact adjoint that avoids such errors is especially challenging if it is to be compatible with state-of-the-art simulation methods used for the turbulent flow itself. Automatic differentiation (AD) can provide code to calculate a nominally exact adjoint, but existing general-purpose AD codes are inefficient to the point of being prohibitive for large-scale turbulence simulations. Here, we analyze the compressible flow equations as discretized using the same high-order workhorse methods used for many high-fidelity compressible turbulence simulations, and formulate a practical space-time discrete-adjoint method without changing the basic discretization. A key step is the definition of a particular discrete analog of the continuous norm that defines our cost functional; our selection leads directly to an efficient Runge-Kutta-like scheme, though it would be just first-order accurate if used outside the adjoint formulation for time integration, with finite-difference spatial operators for the adjoint system. Its computational cost only modestly exceeds that of the flow equations. We confirm that its
Multigrid methods for bifurcation problems: The self adjoint case
NASA Technical Reports Server (NTRS)
Taasan, Shlomo
1987-01-01
This paper deals with multigrid methods for computational problems that arise in the theory of bifurcation and is restricted to the self adjoint case. The basic problem is to solve for arcs of solutions, a task that is done successfully with an arc length continuation method. Other important issues are, for example, detecting and locating singular points as part of the continuation process, switching branches at bifurcation points, etc. Multigrid methods have been applied to continuation problems. These methods work well at regular points and at limit points, while they may encounter difficulties in the vicinity of bifurcation points. A new continuation method that is very efficient also near bifurcation points is presented here. The other issues mentioned above are also treated very efficiently with appropriate multigrid algorithms. For example, it is shown that limit points and bifurcation points can be solved for directly by a multigrid algorithm. Moreover, the algorithms presented here solve the corresponding problems in just a few work units (about 10 or less), where a work unit is the work involved in one local relaxation on the finest grid.
A compactification of the moduli space of principal Higgs bundles over singular curves
NASA Astrophysics Data System (ADS)
Lo Giudice, Alessio; Pustetto, Andrea
2016-12-01
A principal Higgs bundle (P , ϕ) over a singular curve X is a pair consisting of a principal bundle P and a morphism ϕ : X →Ad P ⊗ ΩX1. We construct the moduli space of principal Higgs G-bundles over an irreducible singular curve X using the theory of decorated vector bundles. More precisely, given a faithful representation ρ : G → Sl(V) of G, we consider principal Higgs bundles as triples (E , q , φ) , where E is a vector bundle with rk(E) = dim V over the normalization X ˜ of X, q is a parabolic structure on E and φ :Ea,b → L is a morphism of bundles, L being a line bundle and Ea,b ≑(E⊗a) ⊕ b a vector bundle depending on the Higgs field ϕ and on the principal bundle structure.
Non-Abelian dynamics in the resonant decay of the Higgs after inflation
Enqvist, Kari; Nurmi, Sami; Rusak, Stanislav E-mail: sami.nurmi@helsinki.fi
2014-10-01
We study the resonant decay of the Higgs condensate into weak gauge bosons after inflation and estimate the corrections arising from the non-Abelian self-interactions of the gauge fields. We find that non-Abelian interaction terms induce an effective mass which tends to shut down the resonance. For the broad resonance relevant for the Standard Model Higgs the produced gauge particles backreact on the dynamics of the Higgs condensate before the non-Abelian terms grow large. The non-Abelian terms can however significantly affect the final stages of the resonance after the backreaction. In the narrow resonance regime, which may be important for extensions of the Standard Model, the non-Abelian terms affect already the linear stage and terminate the resonance before the Higgs condensate is affected by the backreaction of decay products.
Light Higgs channel of the resonant decay of magnon condensate in superfluid (3)He-B.
Zavjalov, V V; Autti, S; Eltsov, V B; Heikkinen, P J; Volovik, G E
2016-01-08
In superfluids the order parameter, which describes spontaneous symmetry breaking, is an analogue of the Higgs field in the Standard Model of particle physics. Oscillations of the field amplitude are massive Higgs bosons, while oscillations of the orientation are massless Nambu-Goldstone bosons. The 125 GeV Higgs boson, discovered at Large Hadron Collider, is light compared with electroweak energy scale. Here, we show that such light Higgs exists in superfluid (3)He-B, where one of three Nambu-Goldstone spin-wave modes acquires small mass due to the spin-orbit interaction. Other modes become optical and acoustic magnons. We observe parametric decay of Bose-Einstein condensate of optical magnons to light Higgs modes and decay of optical to acoustic magnons. Formation of a light Higgs from a Nambu-Goldstone mode observed in (3)He-B opens a possibility that such scenario can be realized in other systems, where violation of some hidden symmetry is possible, including the Standard Model.
Light Higgs channel of the resonant decay of magnon condensate in superfluid 3He-B
Zavjalov, V. V.; Autti, S.; Eltsov, V. B.; Heikkinen, P. J.; Volovik, G. E.
2016-01-01
In superfluids the order parameter, which describes spontaneous symmetry breaking, is an analogue of the Higgs field in the Standard Model of particle physics. Oscillations of the field amplitude are massive Higgs bosons, while oscillations of the orientation are massless Nambu-Goldstone bosons. The 125 GeV Higgs boson, discovered at Large Hadron Collider, is light compared with electroweak energy scale. Here, we show that such light Higgs exists in superfluid 3He-B, where one of three Nambu-Goldstone spin-wave modes acquires small mass due to the spin–orbit interaction. Other modes become optical and acoustic magnons. We observe parametric decay of Bose-Einstein condensate of optical magnons to light Higgs modes and decay of optical to acoustic magnons. Formation of a light Higgs from a Nambu-Goldstone mode observed in 3He-B opens a possibility that such scenario can be realized in other systems, where violation of some hidden symmetry is possible, including the Standard Model. PMID:26743951
Geothermal reservoir monitoring based upon spectral-element and adjoint methods
NASA Astrophysics Data System (ADS)
Morency, C.; Templeton, D. C.; Harris, D.; Mellors, R. J.
2011-12-01
Induced seismicity associated with CO2 sequestration, enhanced oil recovery, and enhanced geothermal systems is triggered by fracturing during fluid injection. These events range from magnitude -1 (microseismicity) up to 3.5, for induced seismicity on pre-existing faults. In our approach, we are using seismic data collected at the Salton Sea geothermal field, to improve the current structural model (SCEC CVM4.0 including a 10m resolution topography) and to invert for the moment tensor and source location of the microseismic events. The key here is to refine the velocity model to then precisely invert for the location and mechanism (tensile or shear) of fracture openings. This information is crucial for geothermal reservoir assessment, especially in an unconventional setting where hydrofracturing is used to enhance productivity. The location of pre-existing and formed fractures as well as their type of openings are important elements for strategic decisions. Numerical simulations are performed using a spectral-element method, which contrary to finite-element methods (FEM), uses high degree Lagrange polynomials, allowing the technique to not only handle complex geometries, like the FEM, but also to retain the strength of exponential convergence and accuracy due to the use of high degree polynomials. Finite-frequency sensitivity kernels, used in the non-linear iterative inversions, are calculated based on an adjoint method.
Automated divertor target design by adjoint shape sensitivity analysis and a one-shot method
Dekeyser, W.; Reiter, D.; Baelmans, M.
2014-12-01
As magnetic confinement fusion progresses towards the development of first reactor-scale devices, computational tokamak divertor design is a topic of high priority. Presently, edge plasma codes are used in a forward approach, where magnetic field and divertor geometry are manually adjusted to meet design requirements. Due to the complex edge plasma flows and large number of design variables, this method is computationally very demanding. On the other hand, efficient optimization-based design strategies have been developed in computational aerodynamics and fluid mechanics. Such an optimization approach to divertor target shape design is elaborated in the present paper. A general formulation of the design problems is given, and conditions characterizing the optimal designs are formulated. Using a continuous adjoint framework, design sensitivities can be computed at a cost of only two edge plasma simulations, independent of the number of design variables. Furthermore, by using a one-shot method the entire optimization problem can be solved at an equivalent cost of only a few forward simulations. The methodology is applied to target shape design for uniform power load, in simplified edge plasma geometry.
NASA Astrophysics Data System (ADS)
Morimoto, Kenichi; Kinoshita, Hidenori; Suzuki, Yuji
2016-11-01
In the present study, an adjoint-based shape-optimization method has been developed for designing extended heat transfer surfaces in conjugate heat transfer problems. Here we specifically consider heat conduction-dominated solidification problem under different thermal boundary conditions: (i) the isothermal condition, and (ii) the conjugate condition with thermal coupling between the solidified liquid and the solid wall inside the domain bounded by the extended heat transfer surface. In the present shape-optimization scheme, extended heat transfer surfaces are successively refined in a local way based on the variational information of a cost functional with respect to the shape modification. In the computation of the developed scheme, a meshless method is employed for dealing with the complex boundary shape. For high-resolution analyses with boundary-fitted node arrangement, we have introduced a bubble-mesh method combined with a high-efficiency algorithm for searching neighboring bubbles within a cut-off distance. The present technique can be easily applied to convection problems including high Reynolds number flow. We demonstrate, for the isothermal boundary condition, that the present optimization leads to tree-like fin shapes, which achieve the temperature field with global similarity for different initial fin shapes. We will also show the computational results for the conjugate condition, which would regularize the present optimization due to the fin-efficiency effect.
Higgs potential in the type II seesaw model
Arhrib, A.; Benbrik, R.; Chabab, M.; Rahili, L.; Ramadan, J.; Moultaka, G.; Peyranere, M. C.
2011-11-01
The standard model Higgs sector, extended by one weak gauge triplet of scalar fields with a very small vacuum expectation value, is a very promising setting to account for neutrino masses through the so-called type II seesaw mechanism. In this paper we consider the general renormalizable doublet/triplet Higgs potential of this model. We perform a detailed study of its main dynamical features that depend on five dimensionless couplings and two mass parameters after spontaneous symmetry breaking, and highlight the implications for the Higgs phenomenology. In particular, we determine (i) the complete set of tree-level unitarity constraints on the couplings of the potential and (ii) the exact tree-level boundedness from below constraints on these couplings, valid for all directions. When combined, these constraints delineate precisely the theoretically allowed parameter space domain within our perturbative approximation. Among the seven physical Higgs states of this model, the mass of the lighter (heavier) CP{sub even} state h{sup 0} (H{sup 0}) will always satisfy a theoretical upper (lower) bound that is reached for a critical value {mu}{sub c} of {mu} (the mass parameter controlling triple couplings among the doublet/triplet Higgses). Saturating the unitarity bounds, we find an upper bound m{sub h}{sup 0}
NASA Astrophysics Data System (ADS)
Freire, Igor Leite; Santos Sampaio, Júlio Cesar
2014-02-01
In this paper we consider a class of evolution equations up to fifth-order containing many arbitrary smooth functions from the point of view of nonlinear self-adjointness. The studied class includes many important equations modeling different phenomena. In particular, some of the considered equations were studied previously by other researchers from the point of view of quasi self-adjointness or strictly self-adjointness. Therefore we find new local conservation laws for these equations invoking the obtained results on nonlinearly self-adjointness and the conservation theorem proposed by Nail Ibragimov.
Quantum corrections in Higgs inflation: the Standard Model case
NASA Astrophysics Data System (ADS)
George, Damien P.; Mooij, Sander; Postma, Marieke
2016-04-01
We compute the one-loop renormalization group equations for Standard Model Higgs inflation. The calculation is done in the Einstein frame, using a covariant formalism for the multi-field system. All counterterms, and thus the betafunctions, can be extracted from the radiative corrections to the two-point functions; the calculation of higher n-point functions then serves as a consistency check of the approach. We find that the theory is renormalizable in the effective field theory sense in the small, mid and large field regime. In the large field regime our results differ slightly from those found in the literature, due to a different treatment of the Goldstone bosons.
Collider signatures of flavorful Higgs bosons
NASA Astrophysics Data System (ADS)
Altmannshofer, Wolfgang; Eby, Joshua; Gori, Stefania; Lotito, Matteo; Martone, Mario; Tuckler, Douglas
2016-12-01
Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarks can become dominant. The most interesting decay modes include H /A →c c ,t c ,μ μ ,τ μ and H±→c b ,c s ,μ ν . Searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.
A Historical Profile of the Higgs Boson
Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.
2012-01-31
The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Inflation and pseudo-Goldstone Higgs boson
NASA Astrophysics Data System (ADS)
Alanne, Tommi; Sannino, Francesco; Tenkanen, Tommi; Tuominen, Kimmo
2017-02-01
We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that in such a model the scalar self-couplings can be parametrically suppressed and, consequently, the nonminimal couplings to gravity can be of order one or less, while the inflationary predictions of the model remain compatible with the precision cosmological observations. Furthermore, in the model we study, the existence of the electroweak scale is entirely due to the inflaton field. Our model therefore suggests that inflation and low energy particle phenomenology may be more entwined than assumed so far.
Recent Higgs results from the ATLAS experiment
Brendlinger, Kurt; Collaboration: ATLAS Collaboration
2014-06-24
This paper presents recent results on the Higgs boson from the ATLAS experiment at the Large Hadron Collider. The Collaboration reports on measurements of the signal strength, couplings, and spin of the Higgs in several decay channels. We find all measurements to be consistent with Standard Model predictions. The Higgs branching fraction to invisible particles is constrained and no evidence of physics beyond the Standard Model is found.
Towards magnetic sounding of the Earth's core by an adjoint method
NASA Astrophysics Data System (ADS)
Li, K.; Jackson, A.; Livermore, P. W.
2013-12-01
Earth's magnetic field is generated and sustained by the so called geodynamo system in the core. Measurements of the geomagnetic field taken at the surface, downwards continued through the electrically insulating mantle to the core-mantle boundary (CMB), provide important constraints on the time evolution of the velocity, magnetic field and temperature anomaly in the fluid outer core. The aim of any study in data assimilation applied to the Earth's core is to produce a time-dependent model consistent with these observations [1]. Snapshots of these ``tuned" models provide a window through which the inner workings of the Earth's core, usually hidden from view, can be probed. We apply a variational data assimilation framework to an inertia-free magnetohydrodynamic system (MHD) [2]. Such a model is close to magnetostrophic balance [3], to which we have added viscosity to the dominant forces of Coriolis, pressure, Lorentz and buoyancy, believed to be a good approximation of the Earth's dynamo in the convective time scale. We chose to study the MHD system driven by a static temperature anomaly to mimic the actual inner working of Earth's dynamo system, avoiding at this stage the further complication of solving for the time dependent temperature field. At the heart of the models is a time-dependent magnetic field to which the core-flow is enslaved. In previous work we laid the foundation of the adjoint methodology, applied to a subset of the full equations [4]. As an intermediate step towards our ultimate vision of applying the techniques to a fully dynamic mode of the Earth's core tuned to geomagnetic observations, we present the intermediate step of applying the adjoint technique to the inertia-free Navier-Stokes equation in continuous form. We use synthetic observations derived from evolving a geophysically-reasonable magnetic field profile as the initial condition of our MHD system. Based on our study, we also propose several different strategies for accurately
Bound states in the Higgs model
Di Leo, L.; Darewych, J.W. )
1994-02-01
We derive relativistic wave equations for the bound states of two Higgs bosons within the Higgs sector of the minimal standard model. The variational method and the Hamiltonian formalism of QFT are used to obtain the equations using a simple [vert bar][ital hh][r angle]+[vert bar][ital hhh][r angle] Fock-space ansatz. We present approximate solutions of these equations for a range of Higgs boson masses, and explore the parameter space which corresponds to the existence of two-Higgs-boson bound states.
CP violation in heavy MSSM Higgs scenarios
Carena, M.; Ellis, J.; Lee, J. S.; ...
2016-02-18
We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales MS above a few TeV and a charged Higgs boson mass MH+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observables, for instance electric dipole moments. To consider scenarios with amore » charged Higgs boson much heavier than the Standard Model (SM) particles but much lighter than the supersymmetric particles, we revisit previous calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the presence of CP violating phases, implementing improved matching and renormalization-group (RG) effects, as well as two-loop RG effects from the effective two-Higgs Doublet Model (2HDM) scale MH± to the scale MS. Here, we illustrate the possibility of non-decoupling CP-violating effects in the heavy Higgs sector using new benchmark scenarios named.« less
CP violation in heavy MSSM Higgs scenarios
Carena, M.; Ellis, J.; Lee, J. S.; Pilaftsis, A.; Wagner, C. E. M.
2016-02-18
We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales M_{S} above a few TeV and a charged Higgs boson mass M_{H}+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observables, for instance electric dipole moments. To consider scenarios with a charged Higgs boson much heavier than the Standard Model (SM) particles but much lighter than the supersymmetric particles, we revisit previous calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the presence of CP violating phases, implementing improved matching and renormalization-group (RG) effects, as well as two-loop RG effects from the effective two-Higgs Doublet Model (2HDM) scale M_{H}± to the scale M_{S}. Here, we illustrate the possibility of non-decoupling CP-violating effects in the heavy Higgs sector using new benchmark scenarios named.
Draper, Patrick; Liu Tao; Wagner, Carlos E. M.; Wang, Lian-Tao; Zhang Hao
2011-03-25
We study a limit of the nearly Peccei-Quinn-symmetric next-to-minimal supersymmetric standard model possessing novel Higgs and dark matter (DM) properties. In this scenario, there naturally coexist three light singletlike particles: a scalar, a pseudoscalar, and a singlinolike DM candidate, all with masses of order 0.1-10 GeV. The decay of a standard model-like Higgs boson to pairs of the light scalars or pseudoscalars is generically suppressed, avoiding constraints from collider searches for these channels. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a large direct-detection cross section consistent with the DM direct-detection experiments, CoGeNT and DAMA/LIBRA, preferred region simultaneously. This parameter space is consistent with experimental constraints from LEP, the Tevatron, {Upsilon}, and flavor physics.
Lincoln, Don
2016-07-12
With the discovery of what looks to be the Higgs boson, LHC researchers are turning their attention to the next big question, which is the predicted mass of the newly discovered particles. When the effects of quantum mechanics is taken into account, the mass of the Higgs boson should be incredibly high...perhaps upwards of a quadrillion times higher than what was observed. In this video, Fermilab's Dr. Don Lincoln explains how it is that the theory predicts that the mass is so large and gives at least one possible theoretical idea that might solve the problem. Whether the proposed idea is the answer or not, this question must be answered by experiments at the LHC or today's entire theoretical paradigm could be in jeopardy.
The Higgs Machine Learning Challenge
NASA Astrophysics Data System (ADS)
Adam-Bourdarios, C.; Cowan, G.; Germain-Renaud, C.; Guyon, I.; Kégl, B.; Rousseau, D.
2015-12-01
The Higgs Machine Learning Challenge was an open data analysis competition that took place between May and September 2014. Samples of simulated data from the ATLAS Experiment at the LHC corresponding to signal events with Higgs bosons decaying to τ+τ- together with background events were made available to the public through the website of the data science organization Kaggle (kaggle.com). Participants attempted to identify the search region in a space of 30 kinematic variables that would maximize the expected discovery significance of the signal process. One of the primary goals of the Challenge was to promote communication of new ideas between the Machine Learning (ML) and HEP communities. In this regard it was a resounding success, with almost 2,000 participants from HEP, ML and other areas. The process of understanding and integrating the new ideas, particularly from ML into HEP, is currently underway.
Lincoln, Don
2014-04-28
With the discovery of what looks to be the Higgs boson, LHC researchers are turning their attention to the next big question, which is the predicted mass of the newly discovered particles. When the effects of quantum mechanics is taken into account, the mass of the Higgs boson should be incredibly high...perhaps upwards of a quadrillion times higher than what was observed. In this video, Fermilab's Dr. Don Lincoln explains how it is that the theory predicts that the mass is so large and gives at least one possible theoretical idea that might solve the problem. Whether the proposed idea is the answer or not, this question must be answered by experiments at the LHC or today's entire theoretical paradigm could be in jeopardy.
Adjoint-based airfoil shape optimization in transonic flow
NASA Astrophysics Data System (ADS)
Gramanzini, Joe-Ray
The primary focus of this work is efficient aerodynamic shape optimization in transonic flow. Adjoint-based optimization techniques are employed on airfoil sections and evaluated in terms of computational accuracy as well as efficiency. This study examines two test cases proposed by the AIAA Aerodynamic Design Optimization Discussion Group. The first is a two-dimensional, transonic, inviscid, non-lifting optimization of a Modified-NACA 0012 airfoil. The second is a two-dimensional, transonic, viscous optimization problem using a RAE 2822 airfoil. The FUN3D CFD code of NASA Langley Research Center is used as the ow solver for the gradient-based optimization cases. Two shape parameterization techniques are employed to study their effect and the number of design variables on the final optimized shape: Multidisciplinary Aerodynamic-Structural Shape Optimization Using Deformation (MASSOUD) and the BandAids free-form deformation technique. For the two airfoil cases, angle of attack is treated as a global design variable. The thickness and camber distributions are the local design variables for MASSOUD, and selected airfoil surface grid points are the local design variables for BandAids. Using the MASSOUD technique, a drag reduction of 72.14% is achieved for the NACA 0012 case, reducing the total number of drag counts from 473.91 to 130.59. Employing the BandAids technique yields a 78.67% drag reduction, from 473.91 to 99.98. The RAE 2822 case exhibited a drag reduction from 217.79 to 132.79 counts, a 39.05% decrease using BandAids.
Reconstruction of Mantle Convection in the Geological Past Using the Adjoint Method
NASA Astrophysics Data System (ADS)
Liu, L.; Gurnis, M.
2006-12-01
In mantle convection, earlier work has demonstrated the effectiveness of the adjoint method, widely applied in models of atmospheric circulation. With CitComS.py, the spherical finite element model of mantle convection, and the Pyre framework, we developed an adjoint of the energy equation which, together with the forward modeling, solves for temperature conditions in the past. Our model is applied to several problems, including plume heads impacting and eroding the lithosphere. The assumed true initial condition is a hot spherical blob in the lower mantle, and the final state of the forward model qualitatively shows little information on initial conditions. The adjoint method allows us to retrieve this unknown initial condition iteratively with a first guess. We tested different kinds of first guess initials, and found that a better knowledge of the true initial leads to a better converged solution, both in the sense of mismatch pattern and its RMS norm. Since we have limited knowledge of past mantle structures, earlier adjoint models in mantle convection used arbitrary first guesses which caused large errors in the retrieved initial condition. Our experiments show that a simple backward integration of the energy equation while neglecting thermal diffusion can be used as a first guess and leads to a smaller error. This is potentially important because the overall effectiveness of the adjoint methods is almost doubled using this optimal first guess. We are now experimenting with partial data assimilation with dynamic topography and plate kinematics in conjunction with seismic tomography models.
Aerodynamic Optimization Design of Multi-stage Turbine Using the Continuous Adjoint Method
NASA Astrophysics Data System (ADS)
Chen, Lei; Chen, Jiang
2015-05-01
This paper develops a continuous adjoint formulation for the aerodynamic shape design of a turbine in a multi-stage environment based on S2 surface governed by the Euler equations with source terms. First, given the general expression of the objective function, the adjoint equations and their boundary conditions are derived by introducing the adjoint variable vectors. Then, the final expression of the objective function gradient only includes the terms pertinent to the physical shape variations. The adjoint system is solved numerically by a finite-difference method with the Jameson spatial scheme employing first and third order dissipative flux and the time-marching is conducted by Runge-Kutta time method. Integrating the blade stagger angles, stacking lines and passage perturbation parameterization with the Quasi-Newton method of BFGS, a gradient-based aerodynamic optimization design system is constructed. Finally, the application of the adjoint method is validated through the blade and passage optimization of a 2-stage turbine with an objective function of entropy generation. The efficiency increased by 0.37% with the deviations of the mass flow rate and the pressure ratio within 1% via the optimization, which demonstrates the capability of the gradient-based system for turbine aerodynamic design.
Generalized adjoint consistent treatment of wall boundary conditions for compressible flows
NASA Astrophysics Data System (ADS)
Hartmann, Ralf; Leicht, Tobias
2015-11-01
In this article, we revisit the adjoint consistency analysis of Discontinuous Galerkin discretizations of the compressible Euler and Navier-Stokes equations with application to the Reynolds-averaged Navier-Stokes and k- ω turbulence equations. Here, particular emphasis is laid on the discretization of wall boundary conditions. While previously only one specific combination of discretizations of wall boundary conditions and of aerodynamic force coefficients has been shown to give an adjoint consistent discretization, in this article we generalize this analysis and provide a discretization of the force coefficients for any consistent discretization of wall boundary conditions. Furthermore, we demonstrate that a related evaluation of the cp- and cf-distributions is required. The freedom gained in choosing the discretization of boundary conditions without loosing adjoint consistency is used to devise a new adjoint consistent discretization including numerical fluxes on the wall boundary which is more robust than the adjoint consistent discretization known up to now. While this work is presented in the framework of Discontinuous Galerkin discretizations, the insight gained is also applicable to (and thus valuable for) other discretization schemes. In particular, the discretization of integral quantities, like the drag, lift and moment coefficients, as well as the discretization of local quantities at the wall like surface pressure and skin friction should follow as closely as possible the discretization of the flow equations and boundary conditions at the wall boundary.
Assessing the Impact of Observations on Numerical Weather Forecasts Using the Adjoint Method
NASA Technical Reports Server (NTRS)
Gelaro, Ronald
2012-01-01
The adjoint of a data assimilation system provides a flexible and efficient tool for estimating observation impacts on short-range weather forecasts. The impacts of any or all observations can be estimated simultaneously based on a single execution of the adjoint system. The results can be easily aggregated according to data type, location, channel, etc., making this technique especially attractive for examining the impacts of new hyper-spectral satellite instruments and for conducting regular, even near-real time, monitoring of the entire observing system. This talk provides a general overview of the adjoint method, including the theoretical basis and practical implementation of the technique. Results are presented from the adjoint-based observation impact monitoring tool in NASA's GEOS-5 global atmospheric data assimilation and forecast system. When performed in conjunction with standard observing system experiments (OSEs), the adjoint results reveal both redundancies and dependencies between observing system impacts as observations are added or removed from the assimilation system. Understanding these dependencies may be important for optimizing the use of the current observational network and defining requirements for future observing systems
Higgs-otic inflation and moduli stabilization
NASA Astrophysics Data System (ADS)
Bielleman, Sjoerd; Ibáñez, Luis E.; Pedro, Francisco G.; Valenzuela, Irene; Wieck, Clemens
2017-02-01
We study closed-string moduli stabilization in Higgs-otic inflation in Type IIB orientifold backgrounds with fluxes. In this setup large-field inflation is driven by the vacuum energy of mobile D7-branes. Imaginary selfdual (ISD) three-form fluxes in the background source a μ-term and the necessary monodromy for large field excursions while imaginary anti-selfdual (IASD) three-form fluxes are sourced by non-perturbative contri-butions to the superpotential necessary for moduli stabilization. We analyze Kähler moduli stabilization and backreaction on the inflaton potential in detail. Confirming results in the recent literature, we find that integrating out heavy Kähler moduli leads to a controlled flattening of the inflaton potential. We quantify the flux tuning necessary for stability even during large-field inflation. Moreover, we study the backreaction of supersymmetrically stabilized complex structure moduli and the axio-dilaton in the Kähler metric of the inflaton. Contrary to previous findings, this backreaction can be pushed far out in field space if a similar flux tuning as in the Kähler sector is possible. This allows for a trans-Planckian field range large enough to support inflation.
NASA Astrophysics Data System (ADS)
Yoshida, Keisuke
This study describes the methodology on an inverse estimation of the bed roughness coefficients in open-channels with flood plains. The coefficients are identified by an adjoint shallow-water model and an optimal control theory. Several twin experiments were carried out with the synthetic data in order to validate the method. The data assimilated consists of values of the water level and depth-averaged velocity. The results showed that the coefficients can be accurately predicted with the velocity data, while the estimation fails with the water level data. This is because the cross-sectionally distributed bed roughness does not always influence the lateral profile of the water level, but the local velocity field. Namely, the relation between the lateral profile of the water level and the bed roughness turns out to be non-unique in open-channels with flood plains.
Exploring holographic Composite Higgs models
NASA Astrophysics Data System (ADS)
Croon, Djuna; Dillon, Barry M.; Huber, Stephan J.; Sanz, Veronica
2016-07-01
Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM5, to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of "colours" N , thus increasing the decay constant of the Goldstone Higgs. This is essentially a `Little Randall-Sundrum Model', which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM5 with a small UV cutoff is not in tension with the current experimental data.
NASA Astrophysics Data System (ADS)
Balakin, A. B.; Dehnen, H.; Zayats, A. E.
2007-12-01
We discuss a nonminimal Einstein-Yang-Mills-Higgs model with uniaxial anisotropy in the group space associated with the Higgs field. We apply this theory to the problem of propagation of color and color-acoustic waves in the gravitational background related to the nonminimal regular Wu-Yang monopole.
Scrutinizing the alignment limit in two-Higgs-doublet models. II. mH=125 GeV
NASA Astrophysics Data System (ADS)
Bernon, Jérémy; Gunion, John F.; Haber, Howard E.; Jiang, Yun; Kraml, Sabine
2016-02-01
In the alignment limit of a multidoublet Higgs sector, one of the Higgs mass eigenstates aligns in field space with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider C P -conserving two-Higgs-doublet models (2HDMs) of type I and type II near the alignment limit in which the heavier of the two C P -even Higgs bosons, H , is the SM-like state observed with a mass of 125 GeV, and the couplings of H to gauge bosons approach those of the SM. We review the theoretical structure and analyze the phenomenological implications of this particular realization of the alignment limit, where decoupling of the extra states cannot occur given that the lighter C P -even state h must, by definition, have a mass below 125 GeV. For the numerical analysis, we perform scans of the 2HDM parameter space employing the software packages 2hdmc and lilith, taking into account all relevant pre-LHC constraints, constraints from the measurements of the 125 GeV Higgs signal at the LHC, as well as the most recent limits coming from searches for other Higgs-like states. Implications for Run 2 at the LHC, including expectations for observing the other scalar states, are also discussed.
Neutral Supersymmetric Higgs Boson Searches
Robinson, Stephen Luke
2008-07-01
In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-tagging and in the application of these techniques to the MSSM Higgs search. Work was carried out on the Level-3 trigger b-tagging algorithms. The impact parameter (IP) b-tagger was retuned and the effects of increased instantaneous luminosity on the tagger were studied. An extension of the IP-tagger to use the z-tracking information was developed. A new b-tagger using secondary vertices was developed and commissioned. A tool was developed to allow the use of large multi-run samples for trigger studies involving b-quarks. Offline, a neural network (NN) b-tagger was trained combining the existing offline lifetime based b-tagging tools. The efficiency and fake rate of the NN b-tagger were measured in data and MC. This b-tagger was internally reviewed and certified by the Collaboration and now provides the official b-tagging for all analyses using the Run IIa dataset at D0. A search was performed for neutral MSSM Higgs bosons decaying to a b{bar b} pair and produced in association with one or more b-quarks. Limits are set on the cross-section times the branching ratio for such a process. The limits were interpreted in various MSSM scenarios. This analysis uses the NN b-tagger and was the first to use this tool. The analysis also relies on triggers using the Level-3 IP b-tagging tool described previously. A likelihood discriminant was used to improve the analysis and a neural network was developed to cross-check this technique. The result of the analysis has been submitted to PRL and
Time dependent adjoint-based optimization for coupled fluid-structure problems
NASA Astrophysics Data System (ADS)
Mishra, Asitav; Mani, Karthik; Mavriplis, Dimitri; Sitaraman, Jay
2015-07-01
A formulation for sensitivity analysis of fully coupled time-dependent aeroelastic problems is given in this paper. Both forward sensitivity and adjoint sensitivity formulations are derived that correspond to analogues of the fully coupled non-linear aeroelastic analysis problem. Both sensitivity analysis formulations make use of the same iterative disciplinary solution techniques used for analysis, and make use of an analogous coupling strategy. The information passed between fluid and structural solvers is dimensionally equivalent in all cases, enabling the use of the same data structures for analysis, forward and adjoint problems. The fully coupled adjoint formulation is then used to perform rotor blade design optimization for a four bladed HART2 rotor in hover conditions started impulsively from rest. The effect of time step size and mesh resolution on optimization results is investigated.
NASA Astrophysics Data System (ADS)
Subramanian, Ramanathan Vishnampet Ganapathi
Methods and computing hardware advances have enabled accurate predictions of complex compressible turbulence phenomena, such as the generation of jet noise that motivates the present effort. However, limited understanding of underlying physical mechanisms restricts the utility of such predictions since they do not, by themselves, indicate a route to design improvement. Gradient-based optimization using adjoints can circumvent the flow complexity to guide designs. Such methods have enabled sensitivity analysis and active control of turbulence at engineering flow conditions by providing gradient information at computational cost comparable to that of simulating the flow. They accelerate convergence of numerical design optimization algorithms, though this is predicated on the availability of an accurate gradient of the discretized flow equations. This is challenging to obtain, since both the chaotic character of the turbulence and the typical use of discretizations near their resolution limits in order to efficiently represent its smaller scales will amplify any approximation errors made in the adjoint formulation. Formulating a practical exact adjoint that avoids such errors is especially challenging if it is to be compatible with state-of-the-art simulation methods used for the turbulent flow itself. Automatic differentiation (AD) can provide code to calculate a nominally exact adjoint, but existing general-purpose AD codes are inefficient to the point of being prohibitive for large-scale turbulence simulations. We analyze the compressible flow equations as discretized using the same high-order workhorse methods used for many high-fidelity compressible turbulence simulations, and formulate a practical space--time discrete-adjoint method without changing the basic discretization. A key step is the definition of a particular discrete analog of the continuous norm that defines our cost functional; our selection leads directly to an efficient Runge--Kutta-like scheme
Production of light Higgs pairs in 2-Higgs doublet models via the Higgs-strahlung process at the LHC
NASA Astrophysics Data System (ADS)
Moretti, M.; Moretti, S.; Piccinini, F.; Pittau, R.; Rathsman, J.
2010-11-01
At the Large Hadron Collider, we prove the feasibility to detect pair production of the lightest CP -even Higgs boson h of a Type II 2-Higgs Doublet Model through the process q{overline q^{left( ' right)}} to Vhh (Higgs-strahlung, V = W ± ,Z), in presence of two h to boverline b decays. We also show that, through such production and decay channels, one has direct access to the following Higgs self-couplings, thus enabling one to distinguish between a standard and the Supersymmetric version of the above model: λ Hhh — which constrains the form of the Higgs potential — as well as λ W ± H ∓ h and λ Z Ah — which are required by gauge invariance. Unfortunately, such claims cannot be extended to the Minimal Supersymmetric Standard Model, where the extraction of the same signals is impossible.
Fermionic effective operators and Higgs production at a linear collider
Kile, Jennifer; Ramsey-Musolf, Michael J.
2007-09-01
We study the possible contributions of dimension six operators containing fermion fields to Higgs production at a 500 GeV or 1 TeV e{sup +}e{sup -} linear collider. We show that--depending on the production mechanism--the effects of such operators can be kinematically enhanced relative to standard model (SM) contributions. We determine constraints on the operator coefficients implied by existing precision electroweak measurements and the scale of neutrino mass. We find that even in the presence of such constraints, substantial deviations from SM Higgs production cross sections are possible. We compare the effects of fermionic operators with those associated with purely bosonic operators that have been previously discussed in the literature.
Yukawa alignment in the two-Higgs-doublet model
Pich, Antonio; Tuzon, Paula
2009-11-01
In multi-Higgs-doublet models the alignment in flavor space of the relevant Yukawa matrices guarantees the absence of tree-level flavor-changing couplings of the neutral scalar fields. We analyze the consequences of this condition within the two-Higgs-doublet model and show that it leads to a generic Yukawa structure which contains as particular cases all known specific implementations of the model based on Z{sub 2} symmetries. All possible freedom in the Yukawa sector gets parametrized in terms of three complex couplings {sigma}{sub f}. In spite of having flavor conservation in the neutral scalar couplings, the phases of these three parameters represent potential new sources of CP violation.
Higgs Boson, Magnetic Monopoles and Exotic Smoothness in 4D
NASA Astrophysics Data System (ADS)
Asselmeyer-Maluga, Torsten; Król, Jerzy
We present a model where three incompatible smoothness structures on open 4-manifolds are partly responsible for different physical effects, like: i. the appearance of magnetic matter and Higgs field as non-perturbative solutions of Yang-Mills theory, ii. in cosmology: the inflation, its speed, finite time of the acceleration and the Higgs mass, iii. the perturbative quantum matter as in the standard model of particles. The corresponding 3 smoothness structures are: i. exotic {R}4s with its exotic end S3 × {R}, ii. the fake S3 × Θ (8_{10)}{R} of Freedman, iii. the standard {R}4. It is conjectured that the issue of quantum gravity relies on the incompatibility of the structures.
Higgs mode in a two-dimensional superfluid.
Pollet, L; Prokof'ev, N
2012-07-06
We present solid evidence for the existence of a well-defined Higgs amplitude mode in two-dimensional relativistic field theories based on analytically continued results from quantum Monte Carlo simulations of the Bose-Hubbard model in the vicinity of the superfluid-Mott insulator quantum critical point, featuring emergent particle-hole symmetry and Lorentz invariance. The Higgs boson, seen as a well-defined low-frequency resonance in the spectral density, is quickly pushed to high energies in the superfluid phase and disappears by merging with the broad secondary peak at the characteristic interaction scale. Simulations of a trapped system of ultracold (87)Rb atoms demonstrate that the low-frequency resonance is lost for typical experimental parameters, while the characteristic frequency for the onset of a strong response is preserved.
Dark matter and the Higgs in natural SUSY
NASA Astrophysics Data System (ADS)
Basirnia, Aria; Macaluso, Sebastian; Shih, David
2017-03-01
Null results from dark matter (DM) direct detection experiments and the 125 GeV Higgs both pose serious challenges to minimal supersymmetry. In this paper, we propose a simple extension of the MSSM that economically solves both problems: a "dark sector" consisting of a singlet and a pair of SU(2) doublets. Loops of the dark sector fields help lift the Higgs mass to 125 GeV consistent with naturalness, while the lightest fermion in the dark sector can be viable thermal relic DM, provided that it is mostly singlet. The DM relic abundance is controlled by s-wave annihilation to tops and Higgsinos, leading to a tight relation between the relic abundance and the spin-dependent direct detection cross section. As a result, the model will be fully probed by the next generation of direct detection experiments. Finally we discuss the discovery potential at LHC Run II.
Renormalization of the Higgs sector in the triplet model
NASA Astrophysics Data System (ADS)
Aoki, Mayumi; Kanemura, Shinya; Kikuchi, Mariko; Yagyu, Kei
2012-08-01
We study radiative corrections to the mass spectrum and the triple Higgs boson coupling in the model with an additional Y = 1 triplet field. In this model, the vacuum expectation value for the triplet field is strongly constrained from the electroweak precision data, under which characteristic mass spectrum appear at the tree level; i.e., mH++2 - mH+2 ≃ mH+2 - mA2 and mA2 ≃ mH2, where the CP-even (H), the CP-odd (A) and the doubly-charged (H±±) as well as the singly-charged (H±) Higgs bosons are the triplet-like. We evaluate how the tree-level formulae are modified at the one-loop level. The hhh coupling for the standard model-like Higgs boson (h) is also calculated at the one-loop level. One-loop corrections to these quantities can be large enough for identification of the model by future precision data at the LHC or the International Linear Collider.
SU(2/1) gauge-Higgs unification
NASA Astrophysics Data System (ADS)
Loginov, E. K.
2016-06-01
We discuss a question whether the observed Weinberg angle and Higgs mass are calculable in the formalism based on a construction in which the electroweak gauge group SU(2) × U(1)Y is embedded in the graded Lie group SU(2/1). Here, we follow original works of Ne’eman and Fairlie believing that bosonic fields take their values in the Lie superalgebra and fermionic fields take their values in its representation space. At the same time, our approach differs significantly. The main one is that while for them the gauge symmetry group is SU(2/1), here we consider only symmetries generated by its even subgroup, i.e. symmetries of the standard electroweak model. The reason is that such formalism fixes the quartic Higgs coupling and at the same time removes the sign and statistics problems. The main result is that the presented model predicts values of the Weinberg angle and the Higgs mass correctly up to the two-loop level. Moreover, the model sets the unification scale coinciding with the electroweak scale and automatically describes the fermions correctly with the correct quark and lepton charges.
NASA Technical Reports Server (NTRS)
Yamaleev, N. K.; Diskin, B.; Nielsen, E. J.
2009-01-01
.We study local-in-time adjoint-based methods for minimization of ow matching functionals subject to the 2-D unsteady compressible Euler equations. The key idea of the local-in-time method is to construct a very accurate approximation of the global-in-time adjoint equations and the corresponding sensitivity derivative by using only local information available on each time subinterval. In contrast to conventional time-dependent adjoint-based optimization methods which require backward-in-time integration of the adjoint equations over the entire time interval, the local-in-time method solves local adjoint equations sequentially over each time subinterval. Since each subinterval contains relatively few time steps, the storage cost of the local-in-time method is much lower than that of the global adjoint formulation, thus making the time-dependent optimization feasible for practical applications. The paper presents a detailed comparison of the local- and global-in-time adjoint-based methods for minimization of a tracking functional governed by the Euler equations describing the ow around a circular bump. Our numerical results show that the local-in-time method converges to the same optimal solution obtained with the global counterpart, while drastically reducing the memory cost as compared to the global-in-time adjoint formulation.
Adjoint Sensitivity Analysis of a Coupled Groundwater-Surface Water Model
NASA Astrophysics Data System (ADS)
Kelley, V. A.
2013-12-01
Derivation of the exact equations of Adjoint Sensitivity Analysis for a coupled Groundwater-Surface water model is presented here, with reference to the Stream package in MODFLOW-2005. MODFLOW-2005 offers two distinct packages to simulate river boundary conditions in an aquifer model. They are the RIV (RIVer) Package and the STR (STReam) Package. The STR package simulates a coupled Groundwater and Surface Water flow model. As a result of coupling between the Groundwater and the Surface Water flows, the flows to/from the aquifer depend not just on the river stage and aquifer head at that location (as would happen in the RIV package); but on the river stages and aquifer heads at all upstream locations, in the complex network of streams with all its distributaries and diversions. This requires a substantial modification of the adjoint state equations (not required in RIV Package). The necessary equations for the STR Package have now been developed and implemented the MODFLOW-ADJOINT Code. The exact STR Adjoint code has been validated by comparing with the results from the parameter perturbation method, for the case of San Pedro Model (USGS) and Northern Arizona Regional Aquifer Model (USGS). When the RIV package is used for the same models, the sensitivity analysis results are incorrect for some nodes, indicating the advantage of using the exact methods of the STR Package in MODFLOW-Adjoint code. This exact analysis has been used for deriving the capture functions in the management of groundwater, subject to the constraints on the depletion of surface water supplies. Capture maps are used for optimal location of the pumping wells, their rates of withdrawals, and their timing. Because of the immense savings in computational times, with this Adjoint strategy, it is feasible to embed the groundwater management problem in a stochastic framework (probabilistic approach) to address the uncertainties in the groundwater model.
Higgs portal valleys, stability and inflation
NASA Astrophysics Data System (ADS)
Ballesteros, Guillermo; Tamarit, Carlos
2015-09-01
The measured values of the Higgs and top quark masses imply that the Standard Model potential is very likely to be unstable at large Higgs values. This is particularly problematic during inflation, which sources large perturbations of the Higgs. The instability could be cured by a threshold effect induced by a scalar with a large vacuum expectation value and directly connected to the Standard Model through a Higgs portal coupling. However, we find that in a minimal model in which the scalar generates inflation, this mechanism does not stabilize the potential because the mass required for inflation is beyond the instability scale. This conclusion does not change if the Higgs has a direct weak coupling to the scalar curvature. On the other hand, if the potential is absolutely stable, successful inflation in agreement with current CMB data can occur along a valley of the potential with a Mexican hat profile. We revisit the stability conditions, independently of inflation, and clarify that the threshold effect cannot work if the Higgs portal coupling is too small. We also show that inflation in a false Higgs vacuum appearing radiatively for a tuned ratio of the Higgs and top masses leads to an amplitude of primordial gravitational waves that is far too high, ruling out this possibility.
Physics opportunities at mu+ mu- Higgs factories
C. Blochinger et al.
2004-01-12
We update theoretical studies of the physics opportunities presented by {mu}{sup +} {mu}{sup -} Higgs factories. Interesting measurements of the Standard Model Higgs decays into {bar b}b, {tau}{sup +} {tau}{sup -} and WW* may be possible if the Higgs mass is less than about 160 GeV, as preferred by the precision electroweak data, the mass range being extended by varying appropriately the beam energy resolution. A suitable value of the beam energy resolution would also enable the uncertainty in the b-quark mass to be minimized, facilitating measurements of parameters in the MSSM at such a first {mu}{sup +} {mu}{sup -} Higgs factory. These measurements would be sensitive to radiative corrections to the Higgs-fermion-antifermion decay vertices, which may violate CP. Radiative corrections in the MSSM may also induce CP violation in Higgs-mass mixing, which can be probed via various asymmetries measurable using polarized {mu}{sup +} {mu}{sup -} beams. In addition, Higgs-chargino couplings may be probed at a second {mu}{sup +} {mu}{sup -} Higgs factory.
Higgs Boson Mass, New Physics and Inflation
Shafi, Qaisar
2008-05-13
Finding the Standard Model scalar (Higgs) boson is arguably the single most important mission of the LHC. I review predictions for the Higgs boson mass based on stability and perturbativity arguments, taking into account neutrino oscillations. Other topics that are briefly discussed include the CMSSM, extra dimensions, higher dimensional orbifold GUTS, and primordial inflation based on the Coleman-Weinberg potential.
Bounding the Higgs boson width through interferometry.
Dixon, Lance J; Li, Ye
2013-09-13
We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.
Particlelike solutions in modified gravity: The Higgs monopole
NASA Astrophysics Data System (ADS)
Schlögel, Sandrine; Rinaldi, Massimiliano; Staelens, François; Füzfa, André
2014-08-01
Higgs inflation has received remarkable attention in the last few years due to its simplicity and predictive power. The key point of this model is the nonminimal coupling to gravity in unitary gauge. As such, this theory is in fact a scalar-tensor modification of gravity that needs to be studied also below the energy scales of inflation. Motivated by this goal, we study in great analytical and numerical detail the static and spherically symmetric solutions of the equations of motion in the presence of standard baryonic matter, called "Higgs monopoles" and presented in Füzfa et al. [Phys. Rev. Lett. 111, 12 (2013)]. These particlelike solutions may arise naturally in tensor-scalar gravity with Mexican hat potential and are the only globally regular asymptotically flat solutions with finite classical energy. In the case when the parameters of the potential are taken to be the ones of the standard model, we find that the deviations from general relativity are extremely small, especially for bodies of astrophysical size and density. This allows us to derive a simplified description of the monopole, for which the metric inside the spherical matter distribution can be approximated by the standard metric of general relativity. We study how the properties of these monopoles depend on the strength of the nonminimal coupling to gravity and on the baryonic mass and compactness. An important and original result is the existence of a mechanism of resonant amplification of the Higgs field inside the monopole that comes into play for large nonminimal coupling. We show that this mechanism might degenerate into divergences of the Higgs field that reveal the existence of forbidden combinations of radius and baryonic energy density.
Finite-frequency sensitivity kernels for global seismic wave propagation based upon adjoint methods
NASA Astrophysics Data System (ADS)
Liu, Qinya; Tromp, Jeroen
2008-07-01
We determine adjoint equations and Fréchet kernels for global seismic wave propagation based upon a Lagrange multiplier method. We start from the equations of motion for a rotating, self-gravitating earth model initially in hydrostatic equilibrium, and derive the corresponding adjoint equations that involve motions on an earth model that rotates in the opposite direction. Variations in the misfit function χ then may be expressed as , where δlnm = δm/m denotes relative model perturbations in the volume V, δlnd denotes relative topographic variations on solid-solid or fluid-solid boundaries Σ, and ∇Σδlnd denotes surface gradients in relative topographic variations on fluid-solid boundaries ΣFS. The 3-D Fréchet kernel Km determines the sensitivity to model perturbations δlnm, and the 2-D kernels Kd and Kd determine the sensitivity to topographic variations δlnd. We demonstrate also how anelasticity may be incorporated within the framework of adjoint methods. Finite-frequency sensitivity kernels are calculated by simultaneously computing the adjoint wavefield forward in time and reconstructing the regular wavefield backward in time. Both the forward and adjoint simulations are based upon a spectral-element method. We apply the adjoint technique to generate finite-frequency traveltime kernels for global seismic phases (P, Pdiff, PKP, S, SKS, depth phases, surface-reflected phases, surface waves, etc.) in both 1-D and 3-D earth models. For 1-D models these adjoint-generated kernels generally agree well with results obtained from ray-based methods. However, adjoint methods do not have the same theoretical limitations as ray-based methods, and can produce sensitivity kernels for any given phase in any 3-D earth model. The Fréchet kernels presented in this paper illustrate the sensitivity of seismic observations to structural parameters and topography on internal discontinuities. These kernels form the basis of future 3-D tomographic inversions.
Global Adjoint Tomography: Combining Big Data with HPC Simulations
NASA Astrophysics Data System (ADS)
Bozdag, E.; Lefebvre, M. P.; Lei, W.; Peter, D. B.; Smith, J. A.; Komatitsch, D.; Tromp, J.
2014-12-01
The steady increase in data quality and the number of global seismographic stations have substantially grown the amount of data available for construction of Earth models. Meanwhile, developments in the theory of wave propagation, numerical methods and HPC systems have enabled unprecedented simulations of seismic wave propagation in realistic 3D Earth models which lead the extraction of more information from data, ultimately culminating in the use of entire three-component seismograms.Our aim is to take adjoint tomography further to image the entire planet which is one of the extreme cases in seismology due to its intense computational requirements and vast amount of high-quality seismic data that can potentially be assimilated in inversions. We have started low resolution (T > 27 s, soon will be > 17 s) global inversions with 253 earthquakes for a transversely isotropic crust and mantle model on Oak Ridge National Laboratory's Cray XK7 "Titan" system. Recent improvements in our 3D solvers, such as the GPU version of the SPECFEM3D_GLOBE package, will allow us perform higher-resolution (T > 9 s) and longer-duration (~180 m) simulations to take the advantage of high-frequency body waves and major-arc surface waves to improve imbalanced ray coverage as a result of uneven distribution of sources and receivers on the globe. Our initial results after 10 iterations already indicate several prominent features reported in high-resolution continental studies, such as major slabs (Hellenic, Japan, Bismarck, Sandwich, etc.) and enhancement in plume structures (the Pacific superplume, the Hawaii hot spot, etc.). Our ultimate goal is to assimilate seismic data from more than 6,000 earthquakes within the magnitude range 5.5 ≤ Mw ≤ 7.0. To take full advantage of this data set on ORNL's computational resources, we need a solid framework for managing big data sets during pre-processing (e.g., data requests and quality checks), gradient calculations, and post-processing (e
Adaptive mesh refinement and adjoint methods in geophysics simulations
NASA Astrophysics Data System (ADS)
Burstedde, Carsten
2013-04-01
required by human intervention and analysis. Specifying an objective functional that quantifies the misfit between the simulation outcome and known constraints and then minimizing it through numerical optimization can serve as an automated technique for parameter identification. As suggested by the similarity in formulation, the numerical algorithm is closely related to the one used for goal-oriented error estimation. One common point is that the so-called adjoint equation needs to be solved numerically. We will outline the derivation and implementation of these methods and discuss some of their pros and cons, supported by numerical results.
Probing the non-minimal Higgs sector at the SSC
Gunion, J.F.; Haber, H.E.; Komamiya, S.; Yamamoto, H.; Barbaro-Galtieri, A.
1987-11-01
Non-minimal Higgs sectors occur in the Standard Model with more than one Higgs doublet, as well as in theories that go beyond the Standard Model. In this report, we discuss how Higgs search strategies must be altered, with respect to the Standard Model approaches, in order to probe the non-minimal Higgs sectors at the SSC.
The Minimal Supersymmetric Fat Higgs Model
Harnik, Roni; Kribs, Graham D.; Larson, Daniel T.; Murayama, Hitoshi
2003-11-26
We present a calculable supersymmetric theory of a composite"fat'" Higgs boson. Electroweak symmetry is broken dynamically through a new gauge interaction that becomes strong at an intermediate scale. The Higgs mass can easily be 200-450 GeV along with the superpartner masses, solving the supersymmetric little hierarchy problem. We explicitly verify that the model is consistent with precision electroweak data without fine-tuning. Gauge coupling unification can be maintained despite the inherently strong dynamics involved in electroweak symmetry breaking. Supersymmetrizing the Standard Model therefore does not imply a light Higgs mass, contrary to the lore in the literature. The Higgs sector of the minimal Fat Higgs model has a mass spectrum that is distinctly different from the Minimal Supersymmetric Standard Model.
Minimal Composite Higgs Models at the LHC
Carena, Marcela; Da Rold, Leandro; Pontón, Eduardo
2014-06-26
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) → SO(4) symmetry breaking pattern, assuming the “partial compositeness” paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the Z b ¯ b coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.
Perturbative Higgs coupling C P violation, unitarity, and phenomenology
NASA Astrophysics Data System (ADS)
Englert, Christoph; Nordström, Karl; Sakurai, Kazuki; Spannowsky, Michael
2017-01-01
Perturbative probability conservation provides a strong constraint on the presence of new interactions of the Higgs boson. In this work we consider C P -violating Higgs interactions in conjunction with unitarity constraints in the gauge-Higgs and fermion-Higgs sectors. Injecting signal strength measurements of the recently discovered Higgs boson allows us to make concrete and correlated predictions of how C P violation in the Higgs sector can be directly constrained through collider searches for either characteristic new states or telltale enhancements in multi-Higgs processes.
NASA Astrophysics Data System (ADS)
Chen, H.; Li, K.
2012-12-01
We applied a wave-equation based adjoint wavefield method for seismic illumination/resolution analyses and full waveform inversion. A two-way wave-equation is used to calculate directional and diffracted energy fluxes for waves propagating between sources and receivers to the subsurface target. The first-order staggered-grid pressure-velocity formulation, which lacks the characteristic of being self-adjoint is further validated and corrected to render the modeling operator before its practical application. Despite most published papers on synthetic kernel research, realistic applications to two field experiments are demonstrated and emphasize its practical needs. The Fréchet sensitivity kernels are used to quantify the target illumination conditions. For realistic illumination measurements and resolution analyses, two completely different survey geometries and nontrivial pre-conditioning strategies based on seismic data type are demonstrated and compared. From illumination studies, particle velocity responses are more sensitive to lateral velocity variations than pressure records. For waveform inversion, the more accurately estimated velocity model obtained the deeper the depth of investigation would be reached. To achieve better resolution and illumination, closely spaced OBS receiver interval is preferred. Based on the results, waveform inversion is applied for a gas hydrate site in Taiwan for shallow structure and BSR detection. Full waveform approach potentially provides better depth resolution than ray approach. The quantitative analyses, a by-product of full waveform inversion, are useful for quantifying seismic processing and depth migration strategies.llumination/resolution analysis for a 3D MCS/OBS survey in 2008. Analysis of OBS data shows that pressure (top), horizontal (middle) and vertical (bottom) velocity records produce different resolving power for gas hydrate exploration. ull waveform inversion of 8 OBS data along Yuan-An Ridge in SW Taiwan
Higgs pair productions in the CP-violating two-Higgs-doublet model
NASA Astrophysics Data System (ADS)
Bian, Ligong; Chen, Ning
2016-09-01
In this work, we study the SM-like Higgs pair productions in the framework of the general CP-violating two-Higgs-doublet model. Several constraints are imposed to the model sequentially, including the SM-like Higgs boson signal fits, the precise measurements of the electric dipole moments, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for the heavy Higgs bosons. We show how the CP-violating mixing angles are related to the Higgs cubic self couplings in this setup. Based on these constraints, we suggest benchmark models for the future high-energy collider searches for the Higgs pair productions. The e + e - colliders operating at √{s} = (500 GeV, 1 TeV) are capable of measuring the Higgs cubic self couplings of the benchmark models directly. Afterwards, we estimate the cross sections of the resonance contributions to the Higgs pair productions for the benchmark models at the future LHC and SppC/Fcc-hh runs. Other possible decay modes for the heavy Higgs bosons are also discussed.
Bulk stabilization, the extra-dimensional Higgs portal and missing energy in Higgs events
NASA Astrophysics Data System (ADS)
Diener, Ross; Burgess, C. P.
2013-05-01
To solve the hierarchy problem, extra-dimensional models must explain why the new dimensions stabilize to the right size, and the known mechanisms for doing so require bulk scalars that couple to the branes. Because of these couplings the energetics of dimensional stabilization competes with the energetics of the Higgs vacuum, with potentially observable effects. These effects are particularly strong for one or two extra dimensions because the bulk-Higgs couplings can then be super-renormalizable or dimensionless. Experimental reach for such extra-dimensional Higgs `portals' are stronger than for gravitational couplings because they are less suppressed at low-energies. We compute how Higgs-bulk coupling through such a portal with two extra dimensions back-reacts onto properties of the Higgs boson. When the KK mass is smaller than the Higgs mass, mixing with KK modes results in an invisible Higgs decay width, missing-energy signals at high-energy colliders, and new mechanisms of energy loss in stars and supernovae. Astrophysical bounds turn out to be complementary to collider measurements, with observable LHC signals allowed by existing constraints. We comment on the changes to the Higgs mass-coupling relationship caused by Higgs-bulk mixing, and how the resulting modifications to the running of Higgs couplings alter vacuum-stability and triviality bounds.
Black holes and Higgs stability
Tetradis, Nikolaos
2016-09-20
We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.
The Higgs Working Group: Summary report
D. Cavalli et al.
2004-03-18
In this working group we have investigated the prospects for Higgs boson searches at the Tevatron and LHC and, in particular, the potential of these colliders to determine the Higgs properties once these particles have been found. The analyses were done in the framework of the Standard Model (SM) and its supersymmetric extensions as the minimal (MSSM) and next-to-minimal (NMSSM) supersymmetric extensions. The work for the discovery potential of the LHC mainly concentrated on the difficult regions of previous analyses as those which are plagued by invisible Higgs decays and Higgs decays into supersymmetric particles. Moreover, the additional signatures provided by the weak vector-boson fusion process (WBF) have been addressed and found to confirm the results of previous analyses. A major experimental effort has been put onto charged Higgs boson analyses. The final outcome was a significant improvement of the discovery potential at the Tevatron and LHC than previous analyses suggested. For an accurate determination of Higgs boson couplings, the theoretical predictions for the signal and background processes have to be improved. A lot of progress has been made during and after this workshop for the gluon-fusion gg {yields} H + (0, 1, 2jets) and the associated t{bar t}H production process. A thorough study of the present theoretical uncertainties of signal and background processes has been initialized, culminating in a list of open theoretical problems. A problem of major experimental interest is the proper treatment of processes involving bottom quark densities, which is crucial for some important signal and background processes. Further theoretical improvements have been achieved for the MSSM Higgs boson masses and Higgs bosons in the NMSSM. This report summarizes our work. The first part deals with theoretical developments for the signal and background processes. The second part gives an overview of the present status of Higgs boson searches at the Tevatron. The
Two Higgs doublet models with an S3 symmetry
NASA Astrophysics Data System (ADS)
Cogollo, D.; Silva, João P.
2016-05-01
We study all implementations of the S3 symmetry in the two Higgs doublet models with quarks, consistent with nonzero quark masses and a Cabibbo-Kobayashi-Maskawa (CKM) matrix, which is not block diagonal. We study the impact of the various soft-breaking terms and vacuum expectation values and find an interesting relation between the mixing angles α and β . We also show that, in this minimal setting, only two types of assignments are possible: Either all field sectors are in singlets or all field sectors have a doublet.
Non-decoupling effects in supersymmetric Higgs sectors
NASA Astrophysics Data System (ADS)
Kanemura, Shinya; Shindou, Tetsuo; Yagyu, Kei
2011-05-01
A wide class of Higgs sectors is investigated in supersymmetric standard models. When the lightest Higgs boson (h) looks the standard model one, the mass (mh) and the triple Higgs boson coupling (the hhh coupling) are evaluated at the one-loop level in each model. While mh is at most 120-130 GeV in the minimal supersymmetric standard model (MSSM), that in models with an additional neutral singlet or triplet fields can be much larger. The hhh coupling can also be sensitive to the models: while in the MSSM the deviation from the standard model prediction is not significant, that can be 30-60% in some models such as the MSSM with the additional singlet or with extra doublets and charged singlets. These models are motivated by specific physics problems like the μ-problem, the neutrino mass, the scalar dark matter and so on. Therefore, when h is found at the CERN Large Hadron Collider, we can classify supersymmetric models by measuring mh and the hhh coupling accurately at future collider experiments.
Constraints on gauge-Higgs unification models at the LHC
NASA Astrophysics Data System (ADS)
Kitazawa, Noriaki; Sakai, Yuki
2016-02-01
We examine the possibility of observing the Kaluza-Klein (KK) gluons in gauge-Higgs unification models at the LHC with the energy s=14 TeV. We consider a benchmark model with the gauge symmetry SU(3)C×SU(3)W in five-dimensional spacetime, where SU(3)C is the gauge symmetry of the strong interaction and SU(3)W is that for the electroweak interaction and a Higgs doublet field. It is natural in general to introduce SU(3)C gauge symmetry in five-dimensional spacetime as well as SU(3)W gauge symmetry in gauge-Higgs unification (GHU) models. Since the fifth dimension is compactified to S1/Z 2 orbifold, there are KK modes of gluons in low-energy effective theory in four-dimensional spacetime. We investigate the resonance contribution of the first KK gluon to dijet invariant mass distribution at the LHC, and provide signal-to-noise ratios in various cases of KK gluon masses and kinematical cuts. Although the results are given in a specific benchmark model, we discuss their application to general GHU models with KK gluons. GHU models can be verified or constrained through the physics of the strong interaction, though they are proposed to solve the naturalness problem in electroweak symmetry breaking.
Prospects for a low-mass Higgs boson
Junk, Thomas R.; /Illinois U., Urbana
2007-01-01
The SU(2){sub L} x U(1){sub Y} gauge theory of the electroweak interactions has enjoyed tremendous success over the past four decades, accurately predicting, or at least accommodating, all high-energy collider data. The gauge group must be broken somehow to U(1){sub EM}, because the unbroken theory predicts massless gauge bosons and massless fermions. The Standard Model incorporates a minimal Higgs sector with a single complex doublet field, to break the symmetry spontaneously, but it is not the only possibility. SUSY Higgses, general two-Higgs-doublet models, and other ideas may prove to model nature better than the minimal model. Many of these models, and even the SM, prefer a light Higgs boson, with a mass between the LEP limit of 114.4 GeV and 200 GeV. The Constrained MSSM favors masses under 120 GeV. A survey of the experimental work so far at LEP and the Tevatron, with estimations of the sensitivity of the upcoming LHC experiments is provided.
Higgs Inflation in f(Φ, r) Theory
NASA Astrophysics Data System (ADS)
Chakravarty, Girish Kumar; Mohanty, Subhendra; Singh, Naveen K.
2014-02-01
We generalize the scalar-curvature coupling model ξΦ2R of Higgs inflation to ξΦaRb to study inflation. We compute the amplitude and spectral index of curvature perturbations generated during inflation and fix the parameters of the model by comparing these with the Planck + WP data. We find that if the scalar self-coupling λ is in the range 10-5-0.1, parameter a in the range 2.3-3.6 and b in the range 0.77-0.22 at the Planck scale, one can have a viable inflation model even for ξ ≃ 1. The tensor to scalar ratio r in this model is small and our model with scalar-curvature couplings is not ruled out by observational limits on r unlike the pure (λ )/(4) Φ 4 theory. By requiring the curvature coupling parameter to be of order unity, we have evaded the problem of unitarity violation in scalar-graviton scatterings which plague the ξΦ2R Higgs inflation models. We conclude that the Higgs field may still be a good candidate for being the inflaton in the early universe if one considers higher-dimensional curvature coupling.
Higgs-gluon coupling in warped extra dimensional models with brane kinetic terms
NASA Astrophysics Data System (ADS)
Dey, Ujjal Kumar; Ray, Tirtha Sankar
2016-01-01
Warped models with the Higgs confined to the weak brane and the gauge and matter fields accessing the AdS5 bulk provide a viable setting to address the gauge hierarchy problem. Brane kinetic terms for the bulk fields are known to ease some of the tensions of these models with precision electroweak observables and flavor constraints. We study the loop-driven Higgs coupling to the gluons that are relevant to the Higgs program at the LHC, in this scenario. We demonstrate a partial cancellation in the contribution of the fermionic Kaluza-Klein (KK) towers within such framework relatively independent of the 5D parameters. The entire dependence of this coupling on the new physics arises from the mixing between the Standard Model states and the KK excitations. We find that the present precision in measurement of these couplings can lead to a constraint on the KK scale up to 1.2 TeV at 95% confidence level.
Analysis of Correlated Coupling of Monte Carlo Forward and Adjoint Histories
Ueki, Taro; Hoogenboom, J.E.; Kloosterman, J. L.
2001-02-15
In Monte Carlo correlated coupling, forward and adjoint particle histories are initiated in exactly opposite directions at an arbitrarily placed surface between a physical source and a physical detector. It is shown that this coupling calculation can become more efficient than standard forward calculations. In many cases, the basic form of correlated coupling is less efficient than standard forward calculations. This inherent inefficiency can be overcome by applying a black absorber perturbation to either the forward or the adjoint problem and by processing the product of batch averages as one statistical entity. The usage of the black absorber is based on the invariance of the response flow integral with a material perturbation in either the physical detector side volume in the forward problem or the physical source side volume in the adjoint problem. The batch-average product processing makes use of a quadratic increase of the nonzero coupled-score probability. All the developments have been done in such a way that improved efficiency schemes available in widely distributed Monte Carlo codes can be applied to both the forward and adjoint simulations. Also, the physical meaning of the black absorber perturbation is interpreted based on surface crossing and is numerically validated. In addition, the immediate reflection at the intermediate surface with a controlled direction change is investigated within the invariance framework. This approach can be advantageous for a void streaming problem.
Popov, A. V.
2016-01-15
Metallic lithium is used to demonstrate the possibilities of applying non-self-adjoint operators for quantitative description of orbital excitations of electrons in crystals. It is shown that, the nonequilibrium distribution function can be calculated when solving the spectral problem; therefore, the kinetic properties of a material can also be described with the unified band theory.
Adjoint-operators and non-adiabatic learning algorithms in neural networks
NASA Technical Reports Server (NTRS)
Toomarian, N.; Barhen, J.
1991-01-01
Adjoint sensitivity equations are presented, which can be solved simultaneously (i.e., forward in time) with the dynamics of a nonlinear neural network. These equations provide the foundations for a new methodology which enables the implementation of temporal learning algorithms in a highly efficient manner.
Sensitivity analysis of a model of CO2 exchange in tundra ecosystems by the adjoint method
Waelbroek, C.; Louis, J.F. |
1995-02-01
A model of net primary production (NPP), decomposition, and nitrogen cycling in tundra ecosystems has been developed. The adjoint technique is used to study the sensitivity of the computed annual net CO2 flux to perturbation in initial conditions, climatic inputs, and model`s main parameters describing current seasonal CO2 exchange in wet sedge tundra at Barrow, Alaska. The results show that net CO2 flux is most sensitive to parameters characterizing litter chemical composition and more sensitive to decomposition parameters than to NPP parameters. This underlines the fact that in nutrient-limited ecosystems, decomposition drives net CO2 exchange by controlling mineralization of main nutrients. The results also indicate that the short-term (1 year) response of wet sedge tundra to CO2-induced warming is a significant increase in CO2 emission, creating a positive feedback to atmosphreic CO2 accumulation. However, a cloudiness increase during the same year can severely alter this response and lead to either a slight decrease or a strong increase in emitted CO2, depending on its exact timing. These results demonstrate that the adjoint method is well suited to study systems encountering regime changes, as a single run of the adjoint model provides sensitivities of the net CO2 flux to perturbations in all parameters and variables at any time of the year. Moreover, it is shown that large errors due to the presence of thresholds can be avoided by first delimiting the range of applicability of the adjoint results.
Two-Point Boundary Value Problems and the Method of Adjoints.
ERIC Educational Resources Information Center
Fay, Temple H.; Miller, H. Vincent
1990-01-01
Discusses a numerical technique called the method of adjoints, turning a linear two-point boundary value problem into an initial value problem. Described are steps for using the method in linear or nonlinear systems. Applies the technique to solve a simple pendulum problem. Lists 15 references. (YP)
NASA Astrophysics Data System (ADS)
Liu, Yaning; Niu, Fenglin; Chen, Min; Yang, Wencai
2017-03-01
We construct a new 3-D shear wave speed model of the crust and the uppermost mantle beneath Northeast China using the ambient noise adjoint tomography method. Without intermediate steps of measuring phase dispersion, the adjoint tomography inverts for shear wave speeds of the crust and uppermost mantle directly from 6-40 s waveforms of Empirical Green's functions (EGFs) of Rayleigh waves, which are derived from interferometry of two years of ambient noise data recorded by the 127 Northeast China Extended Seismic Array stations. With an initial 3-D model derived from traditional asymptotic surface wave tomography method, adjoint tomography refines the 3-D model by iteratively minimizing the frequency-dependent traveltime misfits between EGFs and synthetic Green's functions measured in four period bands: 6-15 s, 10-20 s, 15-30 s, and 20-40 s. Our new model shows shear wave speed anomalies that are spatially correlated with known tectonic units such as the Great Xing'an range and the Changbaishan mountain range. The new model also reveals low wave speed conduits in the mid-lower crust and the uppermost mantle with a wave speed reduction indicative of partial melting beneath the Halaha, Xilinhot-Abaga, and Jingpohu volcanic complexes, suggesting that the Cenozoic volcanism in the area has a deep origin. Overall, the adjoint tomographic images show more vertically continuous velocity anomalies with larger amplitudes due to the consideration of the finite frequency and 3-D effects.
Sensitivity analysis of a model of CO2 exchange in tundra ecosystems by the adjoint method
NASA Technical Reports Server (NTRS)
Waelbroek, C.; Louis, J.-F.
1995-01-01
A model of net primary production (NPP), decomposition, and nitrogen cycling in tundra ecosystems has been developed. The adjoint technique is used to study the sensitivity of the computed annual net CO2 flux to perturbation in initial conditions, climatic inputs, and model's main parameters describing current seasonal CO2 exchange in wet sedge tundra at Barrow, Alaska. The results show that net CO2 flux is most sensitive to parameters characterizing litter chemical composition and more sensitive to decomposition parameters than to NPP parameters. This underlines the fact that in nutrient-limited ecosystems, decomposition drives net CO2 exchange by controlling mineralization of main nutrients. The results also indicate that the short-term (1 year) response of wet sedge tundra to CO2-induced warming is a significant increase in CO2 emission, creating a positive feedback to atmosphreic CO2 accumulation. However, a cloudiness increase during the same year can severely alter this response and lead to either a slight decrease or a strong increase in emitted CO2, depending on its exact timing. These results demonstrate that the adjoint method is well suited to study systems encountering regime changes, as a single run of the adjoint model provides sensitivities of the net CO2 flux to perturbations in all parameters and variables at any time of the year. Moreover, it is shown that large errors due to the presence of thresholds can be avoided by first delimiting the range of applicability of the adjoint results.
A coupled-adjoint method for high-fidelity aero-structural optimization
NASA Astrophysics Data System (ADS)
Martins, Joaquim Rafael Rost A.
A new integrated aero-structural design method for aerospace vehicles is presented. The approach combines an aero-structural analysis solver, a coupled aero-structural adjoint solver, a geometry engine, and an efficient gradient-based optimization algorithm. The aero-structural solver ensures accurate solutions by using high-fidelity models for the aerodynamics, structures, and coupling procedure. The coupled aero-structural adjoint solver is used to calculate the sensitivities of aerodynamic and structural cost functions with respect to both aerodynamic shape and structural variables. The aero-structural adjoint sensitivities are compared with those given by the complex-step derivative approximation and finite differences. The proposed method is shown to be both accurate and efficient, exhibiting a significant cost advantage when the gradient of a small number of functions with respect to a large number of design variables is needed. The optimization of a supersonic business jet configuration demonstrates the usefulness and importance of computing aero-structural sensitivities using the coupled-adjoint method.
Using adjoint-based optimization to study wing flexibility in flapping flight
NASA Astrophysics Data System (ADS)
Wei, Mingjun; Xu, Min; Dong, Haibo
2014-11-01
In the study of flapping-wing flight of birds and insects, it is important to understand the impact of wing flexibility/deformation on aerodynamic performance. However, the large control space from the complexity of wing deformation and kinematics makes usual parametric study very difficult or sometimes impossible. Since the adjoint-based approach for sensitivity study and optimization strategy is a process with its cost independent of the number of input parameters, it becomes an attractive approach in our study. Traditionally, adjoint equation and sensitivity are derived in a fluid domain with fixed solid boundaries. Moving boundary is only allowed when its motion is not part of control effort. Otherwise, the derivation becomes either problematic or too complex to be feasible. Using non-cylindrical calculus to deal with boundary deformation solves this problem in a very simple and still mathematically rigorous manner. Thus, it allows to apply adjoint-based optimization in the study of flapping wing flexibility. We applied the ``improved'' adjoint-based method to study the flexibility of both two-dimensional and three-dimensional flapping wings, where the flapping trajectory and deformation are described by either model functions or real data from the flight of dragonflies. Supported by AFOSR.
Probing the Higgs self coupling via single Higgs production at the LHC
Degrassi, G.; Giardino, P. P.; Maltoni, F.; ...
2016-12-16
Here, we propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. Furthermore, the method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, tmore » $$\\bar{t}$$ ) and decay (γγ,WW*/ZZ*→ 4f, b$$\\bar{b}$$,ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We also found that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.« less
Probing the Higgs self coupling via single Higgs production at the LHC
Degrassi, G.; Giardino, P. P.; Maltoni, F.; Pagani, D.
2016-12-16
Here, we propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. Furthermore, the method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, t$\\bar{t}$ ) and decay (γγ,WW*/ZZ*→ 4f, b$\\bar{b}$,ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We also found that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.
Probing the Higgs self coupling via single Higgs production at the LHC
NASA Astrophysics Data System (ADS)
Degrassi, G.; Giardino, P. P.; Maltoni, F.; Pagani, D.
2016-12-01
We propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. The method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production ( ggF, VBF, WH, ZH, toverline{t}H ) and decay (γ γ, W{W}^{ast }/Z{Z}^{ast}to 4f,boverline{b},τ τ ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We find that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.
Full Waveform Inversion Using the Adjoint Method for Earthquake Kinematics Inversion
NASA Astrophysics Data System (ADS)
Tago Pacheco, J.; Metivier, L.; Brossier, R.; Virieux, J.
2014-12-01
Extracting the information contained in seismograms for better description of the Earth structure and evolution is often based on only selected attributes of these signals. Exploiting the entire seismogram, Full Wave Inversion based on an adjoint estimation of the gradient and Hessian operators, has been recognized as a high-resolution imaging technique. Most of earthquake kinematics inversion are still based on the estimation of the Frechet derivatives for the gradient operator computation in linearized optimization. One may wonder the benefit of the adjoint formulation which avoids the estimation of these derivatives for the gradient estimation. Recently, Somala et al. (submitted) have detailed the adjoint method for earthquake kinematics inversion starting from the second-order wave equation in 3D media. They have used a conjugate gradient method for the optimization procedure. We explore a similar adjoint formulation based on the first-order wave equations while using different optimization schemes. Indeed, for earthquake kinematics inversion, the model space is the slip-rate spatio-temporal history over the fault. Seismograms obtained from a dislocation rupture simulation are linearly linked to this slip-rate distribution. Therefore, we introduce a simple systematic procedure based on Lagrangian formulation of the adjoint method in the linear problem of earthquake kinematics. We have developed both the gradient estimation using the adjoint formulation and the Hessian influence using the second-order adjoint formulation (Metivier et al, 2013, 2014). Since the earthquake kinematics is a linear problem, the minimization problem is quadratic, henceforth, only one solution of the Newton equations is needed with the Hessian impact. Moreover, the formal uncertainty estimation over slip-rate distribution could be deduced from this Hessian analysis. On simple synthetic examples for antiplane kinematic rupture configuration in 2D medium, we illustrate the properties of
NASA Astrophysics Data System (ADS)
Finn, John M.
2015-03-01
Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a "special divergence-free" (SDF) property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Feng and Shang [Numer. Math. 71, 451 (1995)], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Richardson and Finn [Plasma Phys. Controlled Fusion 54, 014004 (2012
Finn, John M.
2015-03-01
Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a 'special divergence-free' property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. Wemore » also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Ref. [11], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Ref. [35], appears to work very well.« less
Finn, John M.
2015-03-15
Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a “special divergence-free” (SDF) property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Feng and Shang [Numer. Math. 71, 451 (1995)], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Richardson and Finn [Plasma Phys. Controlled Fusion 54, 014004 (2012
Twin Higgs Asymmetric Dark Matter.
García García, Isabel; Lasenby, Robert; March-Russell, John
2015-09-18
We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20 GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.
NASA Astrophysics Data System (ADS)
Tape, Carl; Liu, Qinya; Tromp, Jeroen
2007-03-01
We employ adjoint methods in a series of synthetic seismic tomography experiments to recover surface wave phase-speed models of southern California. Our approach involves computing the Fréchet derivative for tomographic inversions via the interaction between a forward wavefield, propagating from the source to the receivers, and an `adjoint' wavefield, propagating from the receivers back to the source. The forward wavefield is computed using a 2-D spectral-element method (SEM) and a phase-speed model for southern California. A `target' phase-speed model is used to generate the `data' at the receivers. We specify an objective or misfit function that defines a measure of misfit between data and synthetics. For a given receiver, the remaining differences between data and synthetics are time-reversed and used as the source of the adjoint wavefield. For each earthquake, the interaction between the regular and adjoint wavefields is used to construct finite-frequency sensitivity kernels, which we call event kernels. An event kernel may be thought of as a weighted sum of phase-specific (e.g. P) banana-doughnut kernels, with weights determined by the measurements. The overall sensitivity is simply the sum of event kernels, which defines the misfit kernel. The misfit kernel is multiplied by convenient orthonormal basis functions that are embedded in the SEM code, resulting in the gradient of the misfit function, that is, the Fréchet derivative. A non-linear conjugate gradient algorithm is used to iteratively improve the model while reducing the misfit function. We illustrate the construction of the gradient and the minimization algorithm, and consider various tomographic experiments, including source inversions, structural inversions and joint source-structure inversions. Finally, we draw connections between classical Hessian-based tomography and gradient-based adjoint tomography.
SM Higgs properties measurement at ATLAS
Murray, William
2010-02-10
The discovery of a new particle in the Higgs searches being prepared for LHC will not guarantee that the Standard Model Higgs boson has been seen. This paper discusses the possibilities for measuring the spin, parity and couplings of the particle, under the assumption that it does in fact behave like the Standard Model Higgs. The key question, which cannot alas be answered, is: if it looks like a dog, and barks like a dog, how much of the DNA must we analyse to be sure that it is a dog?
Higgs boson at LHC: a diffractive opportunity
Ducati, M. B. Gay; Silveira, G. G.
2009-03-23
An alternative process is presented for diffractive Higgs boson production in peripheral pp collisions, where the particles interact through the Double Pomeron Exchange. The event rate is computed as a central-rapidity distribution for Tevatron and LHC energies leading to a result around 0.6 pb, higher than the predictions from previous approaches. Therefore, this result arises as an enhanced signal for the detection of the Higgs boson in hadron colliders. The predictions for the Higgs boson photoproduction are compared to the ones obtained from a similar approach proposed by the Durham group, enabling an analysis of the future developments of its application to pp and AA collisions.
Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; Strassler, Matthew
2016-07-01
Here, we present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.
Beyond the discovery: Higgs results from CMS
NASA Astrophysics Data System (ADS)
Mankel, Rainer
2016-11-01
The observation of a Higgs boson at a mass near 125 GeV in the year 2012 has been a milestone for elementary particle physics. Since this fundamental discovery, the CMS collaboration has scrutinized the complete LHC Run I dataset in depth, and studied the properties of the observed state in full detail. This includes investigations of more elusive production and decay modes, as well as searches for first indications of an extended Higgs sector, which would represent very likely a promising gateway to new physics. This article summarizes recent Higgs results from the CMS experiment.
Magnetic Soliton, Homotopy and Higgs Theory,
1986-04-24
OD-AL67 366 NAGETIC SOLITON ONOTOPY ND HIGGS THEORY(U) FOREIGNI n1/ 1TECHNOLOGY D V NRIGHT-PATTERSON AFD ON Y LI ET AL. UNCLSSIIED24 APR 86 FTD-ID...MAGNETIC SOLITON, HOMOTOPY AND HIGGS THEORY by Li Yuanjie and Lei Shizu *. . * . .%..**% . . .-..C./ ~~~Approved for public release; -," Distribution...HOMOTOPY AND HIGGS THEORY By: Li Yuanjie and Lei Shizu English pages: 9 Source: Huazhong Gongxueyuan Xuebao, Vol. 11, Nr. 6, 1983, pp. 65-70 Country of
Searching heavier Higgs boson via di-Higgs production at LHC Run-2
NASA Astrophysics Data System (ADS)
Lü, Lan-Chun; Du, Chun; Fang, Yaquan; He, Hong-Jian; Zhang, Huijun
2016-04-01
The discovery of a light Higgs particle h0 (125 GeV) opens up new prospect for searching heavier Higgs boson(s) at the LHC Run-2, which will unambiguously point to new physics beyond the standard model (SM). We study the detection of a heavier neutral Higgs boson H0 via di-Higgs production channel at the LHC (14 TeV), H0 →h0h0 → WW* γγ. This directly probes the Hhh cubic Higgs interaction, which exists in most extensions of the SM Higgs sector. For the decay products of final states WW*, we include both pure leptonic mode WW* → ℓ ν bar ℓ bar ν and semi-leptonic mode WW* → qqbar‧ ℓν. We analyze signals and backgrounds by performing fast detector simulation for the full process pp → H → hh → WW* γγ → ℓ ν bar ℓ bar νγγ and pp → H → hh → WW* γγ → ℓνqqbar‧ γγ, over the mass range MH = 250- 600 GeV. For generic two-Higgs-doublet models (2HDM), we present the discovery reach of the heavier Higgs boson at the LHC Run-2, and compare it with the current Higgs global fit of the 2HDM parameter space.
Vector-boson production of light Higgs pairs in 2-Higgs doublet models
NASA Astrophysics Data System (ADS)
Moretti, M.; Moretti, S.; Piccinini, F.; Pittau, R.; Rathsman, J.
2007-12-01
At the Large Hadron Collider, we prove the feasibility to detect pair production of the lightest CP-even Higgs boson h of Type II 2-Higgs Doublet Models through qq(') → qq(')hh (vector-boson fusion). We also show that, through the hh → 4b decay channel in presence of heavy-flavour tagging, further exploiting forward/backward jet sampling, one has direct access to the λHhh triple Higgs coupling—which constrains the form of the Higgs potential.
NNLO QCD corrections to Higgs boson production at large transverse momentum
NASA Astrophysics Data System (ADS)
Chen, X.; Cruz-Martinez, J.; Gehrmann, T.; Glover, E. W. N.; Jaquier, M.
2016-10-01
We derive the second-order QCD corrections to the production of a Higgs boson recoiling against a parton with finite transverse momentum, working in the effective field theory in which the top quark contributions are integrated out. To account for quark mass effects, we supplement the effective field theory result by the full quark mass dependence at leading order. Our calculation is fully differential in the final state kinematics and includes the decay of the Higgs boson to a photon pair. It allows one to make next-to-next-to-leading order (NNLO)-accurate theory predictions for Higgs-plus-jet final states and for the transverse momentum distribution of the Higgs boson, accounting for the experimental definition of the fiducial cross sections. The NNLO QCD corrections are found to be moderate and positive, they lead to a substantial reduction of the theory uncertainty on the predictions. We compare our results to 8 TeV LHC data from ATLAS and CMS. While the shape of the data is well-described for both experiments, we agree on the normalization only for CMS. By normalizing data and theory to the inclusive fiducial cross section for Higgs production, good agreement is found for both experiments, however at the expense of an increased theory uncertainty. We make predictions for Higgs production observables at the 13 TeV LHC, which are in good agreement with recent ATLAS data. At this energy, the leading order mass corrections to the effective field theory prediction become significant at large transverse momenta, and we discuss the resulting uncertainties on the predictions.
Partially natural two Higgs doublet models
Draper, Patrick; Haber, Howard E.; Ruderman, Joshua T.
2016-06-21
It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions at the electroweak scale, and the models possess a rich electroweak vacuum structure. Furthermore, the mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.
Higgs Effects in Top Quark Pair Production
Kuhn, J.H.
2003-06-13
Top quark production in p{bar p} and e{sup +}e{sup -} collisions is enhanced by the exchange of a Higgs boson. The enhancement factors are calculated in the threshold region using the Greens function method.
Top partner probes of extended Higgs sectors
NASA Astrophysics Data System (ADS)
Kearney, John; Pierce, Aaron; Thaler, Jesse
2013-08-01
Natural theories of the weak scale often include fermionic partners of the top quark. If the electroweak symmetry breaking sector contains scalars beyond a single Higgs doublet, then top partners can have sizable branching ratios to these extended Higgs sector states. In fact, top partner decays may provide the most promising discovery mode for such scalars, especially given the large backgrounds to direct and associated production. In this paper, we present a search strategy for top partner decays to a charged Higgs boson and a bottom quark, focusing on the case where the charged Higgs dominantly decays to third-generation quarks to yield a multi- b final state. We also discuss ways to extend this search to exotic neutral scalars decaying to bottom quark pairs.
UV-complete composite Higgs models
NASA Astrophysics Data System (ADS)
Agugliaro, Alessandro; Antipin, Oleg; Becciolini, Diego; De Curtis, Stefania; Redi, Michele
2017-02-01
We study confining gauge theories with fermions vectorial under the Standard Model (SM) that produce a Higgs doublet as a Nambu-Goldstone boson. The vacuum misalignment required to break the electroweak symmetry is induced by an elementary Higgs doublet with Yukawa couplings to the new fermions. The physical Higgs is a linear combination of elementary and composite Higgses while the SM fermions remain elementary. The full theory is renormalizable and the SM Yukawa couplings are generated from the ones of the elementary Higgs allowing to eliminate all flavor problems but with interesting effects for electric dipole moments of SM particles. We also discuss how ideas on the relaxation of the electroweak scale could be realized within this framework.
Top and higgs physics at the Tevatron
Pierre Savard
2002-12-23
We present a summary of our experimental understanding of the top quark and discuss the significant improvements expected in Run II at the Fermilab Tevatron Collider. We also discuss prospects for a Higgs boson discovery at the Tevatron.
Has a Higgs-flavon with a 750 GeV mass been detected at the LHC13?
NASA Astrophysics Data System (ADS)
Bolaños, A.; Diaz-Cruz, J. L.; Hernández-Tomé, G.; Tavares-Velasco, G.
2016-10-01
Higgs-flavon fields appear as a part of the Froggatt-Nielsen (FN) mechanism, which attempts to explain the hierarchy of Yukawa couplings. We explore the possibility that the 750 GeV diphoton resonance recently reported at the LHC13 could be identified with a low-scale Higgs-flavon field HF and find the region of the parameter space consistent with CMS and ATLAS data. It is found that the extra vector-like fermions of the ultraviolet completion of the FN mechanism are necessary in order to reproduce the observed signal. We consider a standard model (SM) extension that contains two Higgs doublets (a standard one and an inert one) and one complex FN singlet. The inert doublet includes a stable neutral boson, which provides a viable dark matter candidate, while the mixing of the standard doublet and the FN singlet induces flavor violation in the Higgs sector at the tree-level. Constraints on the parameters of the model are derived from the LHC Higgs data, which include the search for the lepton flavor violating decay of the SM Higgs boson h → μ bar τ. It is also found that in some region of the parameter space the model may give rise to a large branching ratio for the HF → hh decay, of the order of 0.1, which could be searched for at the LHC.
Higgs mass and gravity waves in standard model false vacuum inflation
NASA Astrophysics Data System (ADS)
Notari, Alessio
2015-03-01
In previous publications we have proposed that inflation can be realized in a second minimum of the standard model Higgs potential at energy scales of about 1 016 GeV , if the minimum is not too deep and if a mechanism which allows a transition to the radiation dominated era can be found. This is provided, e.g., by scalar-tensor gravity models or hybrid models. Using such ideas we had predicted the Higgs boson mass to be of about 126 ±3 GeV , which has been confirmed by the LHC, and that a possibly measurable amount of gravity waves should be produced. Using more refined recent theoretical calculations of the renormalization group equations we show that such scenario has the right scale of inflation only for small Higgs mass, lower than about 124 GeV, otherwise gravity waves are overproduced. The precise value is subject to some theoretical error and to experimental errors on the determination of the strong coupling constant. Finally we show that introducing a moderately large nonminimal coupling for the Higgs field the bound can shift to larger values and be reconciled with the LHC measurements of the Higgs mass.
One-loop corrections to the Higgs self-couplings in the singlet extension
NASA Astrophysics Data System (ADS)
Kanemura, Shinya; Kikuchi, Mariko; Yagyu, Kei
2017-04-01
We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state (H) appears in addition to the Higgs boson (h) with the mass 125 GeV. The hhh vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of H → hh is also computed at the one-loop level. We also take into account the bound from the precise measurement of the W boson mass, which gives the upper limit on the mixing angle α between two physical Higgs bosons for a given value of the mass of H (mH). We find that the deviation in the hhh coupling from the prediction in the standard model can maximally be about 250%, 150% and 75% for mH = 300, 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss deviations from the standard model prediction in double Higgs boson production from the gluon fusion at the LHC using the one-loop corrected Higgs boson vertices.
The Gravitational Origin of the Higgs Boson Mass
NASA Astrophysics Data System (ADS)
Winterberg, Friedwardt
2014-06-01
The Lorentzian interpretation of the special theory of relativity explains all the relativistic effects by true deformations of rods and clocks in absolute motion against a preferred reference system, and where Lorentz invariance is a dynamic symmetry with the Galilei group the more fundamental kinematic symmetry of nature. In an exactly nonrelativistic quantum field theory the particle number operator commutes with the Hamilton operator which permits to introduce negative besides positive masses as the fundamental constituents of matter. Assuming that space is densely filled with an equal number of positive and negative locally interacting Planck mass particles, with those of equal sign repelling and those of opposite sign attracting each other, all the particles except the Planck mass particles are quasiparticles of this positive-negative-mass Planck mass plasma. Very much as the Van der Waals forces is the residual short-range electromagnetic force holding condensed matter together, and the strong nuclear force the residual short range gluon force holding together nuclear matter, it is conjectured that the Higgs field is the residual short range gravitational force holding together pre-quark matter made up from large positive and negative masses of the order ±1013 GeV. This hypothesis supports a theory by Dehnen and Frommert who have shown that the Higgs field acts like a short range gravitational field, with a strength about 32 orders of magnitude larger than one would expect in the absence of the positive-negative pre-quark mass hypothesis.
Top-Higgs and top-pion phenomenology in the top triangle moose model
NASA Astrophysics Data System (ADS)
Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam
2011-03-01
We discuss the deconstructed version of a topcolor-assisted technicolor model wherein the mechanism of top quark mass generation is separated from the rest of electroweak symmetry breaking. The minimal deconstructed version of this scenario is a “triangle moose” model, where the top quark gets its mass from coupling to a top-Higgs field, while the gauge boson masses are generated from a Higgsless sector. The spectrum of the model includes scalar (top-Higgs) and pseudoscalar (top-pion) states. In this paper, we study the properties of these particles, discuss their production mechanisms and decay modes, and suggest how best to search for them at the LHC.
Top-Higgs and top-pion phenomenology in the top triangle moose model
Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam
2011-03-01
We discuss the deconstructed version of a topcolor-assisted technicolor model wherein the mechanism of top quark mass generation is separated from the rest of electroweak symmetry breaking. The minimal deconstructed version of this scenario is a ''triangle moose'' model, where the top quark gets its mass from coupling to a top-Higgs field, while the gauge boson masses are generated from a Higgsless sector. The spectrum of the model includes scalar (top-Higgs) and pseudoscalar (top-pion) states. In this paper, we study the properties of these particles, discuss their production mechanisms and decay modes, and suggest how best to search for them at the LHC.
Aspects of quantum corrections in a Lorentz-violating extension of the Abelian Higgs model
NASA Astrophysics Data System (ADS)
Brito, L. C. T.; Fargnoli, H. G.; Baêta Scarpelli, A. P.
2013-06-01
We investigate new aspects related to the Abelian gauge-Higgs model with the addition of the Carroll-Field-Jackiw term. We focus on one-loop quantum corrections to the photon and Higgs sectors due to spontaneous breaking of gauge symmetry and show that new finite and definite Lorentz-breaking terms are induced. Specifically in the gauge sector, a CPT-even aether term is induced. Besides, aspects of the one-loop renormalization of the background vector-dependent terms are discussed.
A Search for Dark Higgs Bosons
Lees, J.P.
2012-06-08
Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs boson using 516 fb{sup -1} of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the Standard Model-dark sector mixing angle and the dark sector coupling constant.
Improving acceptance for Higgs events at CDF
Sforza, Federico; /INFN, Pisa
2008-03-01
The Standard Model of elementary particles predicts the existence of the Higgs boson as the responsable of the electroweak symmetry breaking, the process by which fermions and vector bosons acquire mass. The Higgs existence is one of the most important questions in the present high energy physics research. This work concerns the search of W H associate production at the CDF II experiment (Collider Detector at Fermilab).
Discovering uncolored naturalness in exotic Higgs decays
NASA Astrophysics Data System (ADS)
Curtin, David; Verhaaren, Christopher B.
2015-12-01
Solutions to the hierarchy problem usually require top partners. In standard SUSY or composite Higgs theories, the partners carry SM color and are becoming increasingly constrained by LHC searches. However, theories like Folded SUSY (FS), Twin Higgs (TH) and Quirky Little Higgs (QLH) introduce uncolored top partners, which can be SM singlets or carry electroweak charge. Their small production cross section left doubt as to whether the LHC can effectively probe such scenarios. Typically, these partners are charged under their own mirror color gauge group. In FS and QLH, the absence of light mirror matter allows glueballs to form at the bottom of the mirror spectrum. This is also the case in some TH realizations. The Higgs can decay to these mirror glueballs, with the glueballs decaying into SM particles with potentially observable lifetimes. We undertake the first detailed study of this glueball signature and quantitatively demonstrate the discovery potential of uncolored naturalness via exotic Higgs decays at the LHC and a potential future 100TeV collider. Our findings indicate that mirror glueballs are the smoking gun signature of natural FS and QLH type theories, in analogy to tree-level Higgs coupling shifts for the TH. We show that glueball masses in the ˜ 10-60 GeV mass range are theoretically preferred. Careful treatment of lifetime, mirror-hadronization and non-perturbative uncertainties is required to perform meaningful collider studies. We outline several new search strategies for exotic Higgs decays of the form h → XX → 4 f at the LHC, with X having lifetimes in the 10 μm to km range. We find that FS stops can be probed with masses up to 600 (1100) GeV at the LHC with 300 (3000) fb-1 of data, and TH top partners could be accessible with masses up to 900 (1500) GeV. This makes exotic Higgs decays the prime discovery channel for uncolored naturalness at the LHC.
Higgs results from the Tevatron Run II
Tuchming, B.; /DAPNIA, Saclay
2005-01-01
The data taken at the Tevatron experiments have been analyzed to search for Higgs bosons. For the Standard Model Higgs searches, no excess is observed, the data are in good agreement with the expectations, so that limits are set on the production rates. For various theoretical models beyond the Standard Model, there is no excess either, which allows to derive constraints in their respective parameter spaces.
The Higgs boson in the Standard Model
NASA Astrophysics Data System (ADS)
Djouadi, Abdelhak; Grazzini, Massimiliano
2016-10-01
The major goal of the Large Hadron Collider is to probe the electroweak symmetry breaking mechanism and the generation of the elementary particle masses. In the Standard Model this mechanism leads to the existence of a scalar Higgs boson with unique properties. We review the physics of the Standard Model Higgs boson, discuss its main search channels at hadron colliders and the corresponding theoretical predictions. We also summarize the strategies to study its basic properties.
Factorization and NNLL Resummation for Higgs production with a jet veto
NASA Astrophysics Data System (ADS)
Becher, Thomas; Neubert, Matthias
2012-07-01
Using methods of effective field theory, we derive the first all-order factorization theorem for the Higgs-boson production cross section with a jet veto, imposed by means of a standard sequential recombination jet algorithm. Like in the case of small-qT resummation in Drell-Yan and Higgs production, the factorization is affected by a collinear anomaly. Our analysis provides the basis for a systematic resummation of large logarithms { ln }( {{m_H}/p_T^{{veto}}} ) beyond leading-logarithmic order. Specifically, we present predictions for the resummed jetveto cross section and efficiency at next-to-next-to-leading logarithmic order. Our results have important implications for Higgs-boson searches at the LHC, where a jet veto is required to suppress background events.
Coupling of Higgs and Leggett modes in non-equilibrium superconductors.
Krull, H; Bittner, N; Uhrig, G S; Manske, D; Schnyder, A P
2016-06-21
In equilibrium systems amplitude and phase collective modes are decoupled, as they are mutually orthogonal excitations. The direct detection of these Higgs and Leggett collective modes by linear-response measurements is not possible, because they do not couple directly to the electromagnetic field. In this work, using numerical exact simulations we show for the case of two-gap superconductors, that optical pump-probe experiments excite both Higgs and Leggett modes out of equilibrium. We find that this non-adiabatic excitation process introduces a strong interaction between the collective modes, which is absent in equilibrium. Moreover, we propose a type of pump-probe experiment, which allows to probe and coherently control the Higgs and Leggett modes, and thus the order parameter directly. These findings go beyond two-band superconductors and apply to general collective modes in quantum materials.
Coupling of Higgs and Leggett modes in non-equilibrium superconductors
Krull, H.; Bittner, N.; Uhrig, G. S.; Manske, D.; Schnyder, A. P.
2016-01-01
In equilibrium systems amplitude and phase collective modes are decoupled, as they are mutually orthogonal excitations. The direct detection of these Higgs and Leggett collective modes by linear-response measurements is not possible, because they do not couple directly to the electromagnetic field. In this work, using numerical exact simulations we show for the case of two-gap superconductors, that optical pump–probe experiments excite both Higgs and Leggett modes out of equilibrium. We find that this non-adiabatic excitation process introduces a strong interaction between the collective modes, which is absent in equilibrium. Moreover, we propose a type of pump–probe experiment, which allows to probe and coherently control the Higgs and Leggett modes, and thus the order parameter directly. These findings go beyond two-band superconductors and apply to general collective modes in quantum materials. PMID:27323887
Higgs mass from compositeness at a multi-TeV scale
Cheng, Hsin -Chia; Dobrescu, Bogdan A.; Gu, Jiayin
2014-08-18
Within composite Higgs models based on the top seesaw mechanism, we show that the Higgs field can arise as the pseudo Nambu-Goldstone boson of the broken U(3)more » $$_{L}$$ chiral symmetry associated with a vector-like quark and the t-b doublet. As a result, the lightest CP-even neutral state of the composite scalar sector is lighter than the top quark, and can be identified as the newly discovered Higgs boson. As a result, constraints on weak-isospin violation push the chiral symmetry breaking scale above a few TeV, implying that other composite scalars are probably too heavy to be probed at the LHC, but may be within reach at a future hadron collider with center-of-mass energy of about 100 TeV.« less
Higgs mass from compositeness at a multi-TeV scale
Cheng, Hsin -Chia; Dobrescu, Bogdan A.; Gu, Jiayin
2014-08-18
Within composite Higgs models based on the top seesaw mechanism, we show that the Higgs field can arise as the pseudo Nambu-Goldstone boson of the broken U(3)$_{L}$ chiral symmetry associated with a vector-like quark and the t-b doublet. As a result, the lightest CP-even neutral state of the composite scalar sector is lighter than the top quark, and can be identified as the newly discovered Higgs boson. As a result, constraints on weak-isospin violation push the chiral symmetry breaking scale above a few TeV, implying that other composite scalars are probably too heavy to be probed at the LHC, but may be within reach at a future hadron collider with center-of-mass energy of about 100 TeV.
NASA Astrophysics Data System (ADS)
Reece, Matthew
2016-10-01
I give an overview of the physics potential at possible future e+e- colliders, including the ILC, FCC-ee, and CEPC. The goal is to explain some of the measurements that can be done in the context of electroweak precision tests and Higgs couplings, to compare some of the options under consideration, and to put the measurements in context by summarizing their implications for some new physics scenarios. This is a writeup of a plenary talk at the Hong Kong University of Science and Technology Jockey Club Institute for Advanced Study Program on High Energy Physics Conference, 18-21 January 2016. Some previously unpublished electroweak precision results for FCC-ee and CEPC are included.
Long lived fourth generation and the Higgs
NASA Astrophysics Data System (ADS)
Keung, Wai-Yee; Schwaller, Pedro
2011-06-01
A chiral fourth generation is a simple and well motivated extension of the standard model, and has important consequences for Higgs phenomenology. Here we consider a scenario where the fourth generation neutrinos are long lived and have both a Dirac and Majorana mass term. Suchneutrinoscanbeaslightas40GeVandcanbethedominant decay mode of the Higgs boson for Higgs masses below the W-boson threshold. We study the effect of the Majorana mass term on the Higgs branching fractions and reevaluate the Tevatron constraints on the Higgs mass. We discuss the prospects for the LHC to detect the semi-invisible Higgs decays into fourth generation neutrino pairs. Under the assumption that the lightest fourth generation neutrino is stable, its thermal relic density can be up to 20% of the observed dark matter density in the universe. This is in agreement with current constraints on the spin dependent neutrino-neutron cross section, but can be probed by the next generation of dark matter direct detection experiments.
A Historical Profile of the Higgs Boson
NASA Astrophysics Data System (ADS)
Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.
2016-10-01
The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible production in e+ e-, bar pp and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which were complemented by searches at the Fermilab Tevatron. Then the LHC experiments ATLAS and CMS entered the hunt, announcing on July 4, 2012 the discovery of a "Higgs-like" particle with a mass of about 125 GeV. This identification has been supported by subsequent measurements of its spin, parity and coupling properties. It was widely anticipated that the Higgs boson would be accompanied by supersymmetry, although other options, like compositeness, were not completely excluded. So far there are no signs of any new physics, and the measured properties of the Higgs boson are consistent with the predictions of the minimal Standard Model. This article reviews some of the key historical developments in Higgs physics over the past half-century.
Collider signatures of flavorful Higgs bosons
Altmannshofer, Wolfgang; Eby, Joshua; Gori, Stefania; ...
2016-12-30
Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarksmore » can become dominant. The most interesting decay modes include H/A → cc,tc,μμ,τμ and H± → cb,cs,μν. As a result, searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.« less
Collider signatures of flavorful Higgs bosons
Altmannshofer, Wolfgang; Eby, Joshua; Gori, Stefania; Lotito, Matteo; Martone, Mario; Tuckler, Douglas
2016-12-30
Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarks can become dominant. The most interesting decay modes include H/A → cc,tc,μμ,τμ and H^{±} → cb,cs,μν. As a result, searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.
Sphalerons in composite and nonstandard Higgs models
NASA Astrophysics Data System (ADS)
Spannowsky, Michael; Tamarit, Carlos
2017-01-01
After the discovery of the Higgs boson and the rather precise measurement of all electroweak boson's masses the local structure of the electroweak symmetry breaking potential is already quite well established. However, despite being a key ingredient to a fundamental understanding of the underlying mechanism of electroweak symmetry breaking, the global structure of the electroweak potential remains entirely unknown. The existence of sphalerons, unstable solutions of the classical action of motion that are interpolating between topologically distinct vacua, is a direct consequence of the Standard Model's SU (2 )L gauge group. Nevertheless, the sphaleron energy depends on the shape of the Higgs potential away from the minimum and can therefore be a litmus test for its global structure. Focusing on two scenarios, the minimal composite Higgs model SO (5 )/SO (4 ) or an elementary Higgs with a deformed electroweak potential, we calculate the change of the sphaleron energy compared to the Standard Model prediction. We find that the sphaleron energy would have to be measured to O (10 )% accuracy to exclude sizeable global deviations from the Standard Model Higgs potential. We further find that because of the periodicity of the scalar potential in composite Higgs models a second sphaleron branch with larger energy arises.
Cosmology with nonminimal kinetic coupling and a Higgs-like potential
Matsumoto, Jiro; Sushkov, Sergey V. E-mail: sergey_sushkov@mail.ru
2015-11-01
We consider cosmological dynamics in the theory of gravity with the scalar field possessing the nonminimal kinetic coupling to curvature given as κG{sup μν}φ{sub ,μ}φ{sub ,ν}, and the Higgs-like potential . Using the dynamical system method, we analyze stationary points, their stability, and all possible asymptotical regimes of the model under consideration. We show that the Higgs field with the kinetic coupling provides an existence of accelerated regimes of the Universe evolution. There are three possible cosmological scenarios with acceleration: (i) The late-time de Sitter epoch when the Hubble parameter tends to the constant value, as t → ∞, while the scalar field tends to zero, 0φ(t)→ , so that the Higgs potential reaches its local maximum . (ii) The Big Rip when H(t)∼(t{sub *}−t){sup −1} → ∞ and φ(t)∼(t{sub *}−t){sup −2} → ∞ as t → t{sub *}. (iii) The Little Rip when H(t)∼ t{sup 1/2} → ∞ and φ(t)∼ t{sup 1/4} → ∞ as t → ∞. Also, we derive modified slow-roll conditions for the Higgs field and demonstrate that they lead to the Little Rip scenario.
NASA Technical Reports Server (NTRS)
Grossman, Bernard
1999-01-01
The technical details are summarized below: Compressible and incompressible versions of a three-dimensional unstructured mesh Reynolds-averaged Navier-Stokes flow solver have been differentiated and resulting derivatives have been verified by comparisons with finite differences and a complex-variable approach. In this implementation, the turbulence model is fully coupled with the flow equations in order to achieve this consistency. The accuracy demonstrated in the current work represents the first time that such an approach has been successfully implemented. The accuracy of a number of simplifying approximations to the linearizations of the residual have been examined. A first-order approximation to the dependent variables in both the adjoint and design equations has been investigated. The effects of a "frozen" eddy viscosity and the ramifications of neglecting some mesh sensitivity terms were also examined. It has been found that none of the approximations yielded derivatives of acceptable accuracy and were often of incorrect sign. However, numerical experiments indicate that an incomplete convergence of the adjoint system often yield sufficiently accurate derivatives, thereby significantly lowering the time required for computing sensitivity information. The convergence rate of the adjoint solver relative to the flow solver has been examined. Inviscid adjoint solutions typically require one to four times the cost of a flow solution, while for turbulent adjoint computations, this ratio can reach as high as eight to ten. Numerical experiments have shown that the adjoint solver can stall before converging the solution to machine accuracy, particularly for viscous cases. A possible remedy for this phenomenon would be to include the complete higher-order linearization in the preconditioning step, or to employ a simple form of mesh sequencing to obtain better approximations to the solution through the use of coarser meshes. . An efficient surface parameterization based
NASA Technical Reports Server (NTRS)
Grossman, Bernard
1999-01-01
Compressible and incompressible versions of a three-dimensional unstructured mesh Reynolds-averaged Navier-Stokes flow solver have been differentiated and resulting derivatives have been verified by comparisons with finite differences and a complex-variable approach. In this implementation, the turbulence model is fully coupled with the flow equations in order to achieve this consistency. The accuracy demonstrated in the current work represents the first time that such an approach has been successfully implemented. The accuracy of a number of simplifying approximations to the linearizations of the residual have been examined. A first-order approximation to the dependent variables in both the adjoint and design equations has been investigated. The effects of a "frozen" eddy viscosity and the ramifications of neglecting some mesh sensitivity terms were also examined. It has been found that none of the approximations yielded derivatives of acceptable accuracy and were often of incorrect sign. However, numerical experiments indicate that an incomplete convergence of the adjoint system often yield sufficiently accurate derivatives, thereby significantly lowering the time required for computing sensitivity information. The convergence rate of the adjoint solver relative to the flow solver has been examined. Inviscid adjoint solutions typically require one to four times the cost of a flow solution, while for turbulent adjoint computations, this ratio can reach as high as eight to ten. Numerical experiments have shown that the adjoint solver can stall before converging the solution to machine accuracy, particularly for viscous cases. A possible remedy for this phenomenon would be to include the complete higher-order linearization in the preconditioning step, or to employ a simple form of mesh sequencing to obtain better approximations to the solution through the use of coarser meshes. An efficient surface parameterization based on a free-form deformation technique has been
NASA Astrophysics Data System (ADS)
Humbird, Kelli D.; McClarren, Ryan G.
2017-03-01
Uncertainty quantification and sensitivity analyses are a vital component for predictive modeling in the sciences and engineering. The adjoint approach to sensitivity analysis requires solving a primary system of equations and a mathematically related set of adjoint equations. The information contained in the equations can be combined to produce sensitivity information in a computationally efficient manner. In this work, sensitivity analyses are performed on systems described by flux-limited radiative diffusion using the adjoint approach. The sensitivities computed are shown to agree with standard perturbation theory and require significantly less computational time. The adjoint approach saves the computational cost of one forward solve per sensitivity, making the method attractive when multiple sensitivities are of interest.
Radiative corrections to the triple Higgs coupling in the inert Higgs doublet model
NASA Astrophysics Data System (ADS)
Arhrib, Abdesslam; Benbrik, Rachid; El Falaki, Jaouad; Jueid, Adil
2015-12-01
We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and e + e - Linear Collider machines, accurate theoretical predictions are required. We study the radiative corrections to the triple Higgs coupling hhh and to hZZ, hW W couplings in the context of the IHDM. By combining several theoretical and experimental constraints on parameter space, we show that extra particles might modify the triple Higgs coupling near threshold regions. Finally, we discuss the effect of these corrections on the double Higgs production signal at the e + e - LC and show that they can be rather important.
Carena, Marcela; Haber, Howard E.; Low, Ian; ...
2015-02-03
Precision measurements of the Higgs boson properties at the LHC provide relevant constraints on possible weak-scale extensions of the Standard Model (SM). In the context of the minimal supersymmetric Standard Model (MSSM) these constraints seem to suggest that all the additional, non-SM-like Higgs bosons should be heavy, with masses larger than about 400 GeV. This article shows that such results do not hold when the theory approaches the conditions for “alignment independent of decoupling,” where the lightest CP-even Higgs boson has SM-like tree-level couplings to fermions and gauge bosons, independently of the nonstandard Higgs boson masses. In addition, the combinationmore » of current bounds from direct Higgs boson searches at the LHC, along with the alignment conditions, have a significant impact on the allowed MSSM parameter space yielding light additional Higgs bosons. In particular, after ensuring the correct mass for the lightest CP-even Higgs boson, we find that precision measurements and direct searches are complementary and may soon be able to probe the region of non-SM-like Higgs boson with masses below the top quark pair mass threshold of 350 GeV and low to moderate values of tanβ.« less
Carena, Marcela; Haber, Howard E.; Low, Ian; Shah, Nausheen R.; Wagner, Carlos E. M.
2015-02-03
Precision measurements of the Higgs boson properties at the LHC provide relevant constraints on possible weak-scale extensions of the Standard Model (SM). In the context of the minimal supersymmetric Standard Model (MSSM) these constraints seem to suggest that all the additional, non-SM-like Higgs bosons should be heavy, with masses larger than about 400 GeV. This article shows that such results do not hold when the theory approaches the conditions for “alignment independent of decoupling,” where the lightest CP-even Higgs boson has SM-like tree-level couplings to fermions and gauge bosons, independently of the nonstandard Higgs boson masses. In addition, the combination of current bounds from direct Higgs boson searches at the LHC, along with the alignment conditions, have a significant impact on the allowed MSSM parameter space yielding light additional Higgs bosons. In particular, after ensuring the correct mass for the lightest CP-even Higgs boson, we find that precision measurements and direct searches are complementary and may soon be able to probe the region of non-SM-like Higgs boson with masses below the top quark pair mass threshold of 350 GeV and low to moderate values of tanβ.
Special Mixing of the Neutral Higgs Bosons States in the Standard Model with Two Higgs Doublets
Juarez W, S. R.; Morales C, D.
2008-07-02
The Higgs sector of the Standard Model (SM) requires careful investigation in order to look for new physics. In the SM the masses of the physical particles arise, after the spontaneous symmetry breaking (SSB), through its couplings with a single Higgs doublet. In the simplest extension of the SM, called the Two Higgs Doublet Model (2HDM), a second Higgs doublet is introduced, with a potential dependent on seven parameters, which are related to five Higgs bosons, whose existence is predicted by the model. In this context, we obtain the masses and the physical eigenstates of the new scalar particles: two charged ones (H{sup {+-}}) and three neutral (A{sup 0}), (h{sup 0},H{sup 0}). We explore a particular situation in which very simple relations between the parameters and the masses are satisfied.
Dual Superconductivity in Abelian Higgs Model of QCD
NASA Astrophysics Data System (ADS)
Rajput, B. S.
2017-04-01
The study of generalized field associated with Abelian dyons has been undertaken and it has been demonstrated that topologically, a non-Abelian gauge theory is equivalent to a set of Abelian gauge theories supplemented by dyons which undergo condensation leading to confinement and consequently to superconducting model of QCD vacuum, where the Higgs field plays the role of a regulator only. Constructing the effective action for dyonic field in Abelian projection of QCD, it has been demonstrated that any charge (electrical or magnetic) of dyon screens its own direct potential to which it minimally couples and anti-screens the dual potential leading to dual superconductivity in accordance with generalized Meissner effect. In this Abelian projection of QCD an Abelian Higgs model (AHM) has been successfully constructed and it has been shown to incorporate dual superconductivity and confinement as the consequence of dyonic condensation. It has been demonstrated that in AHM t' Hooft loop creates the string (AHM-string) around which the monopole current under London limit leads to vanishing coherence length in the chromo-magnetic superconductor. It has also been shown that in London limit the squared density of monopole current around AHM-string has a maximum at the distance of the order of penetration length.
125 GeV Higgs state in the context of four generations with two Higgs doublets
NASA Astrophysics Data System (ADS)
Geller, Michael; Bar-Shalom, Shaouly; Eilam, Gad; Soni, Amarjit
2012-12-01
We interpret the recent discovery of a 125 GeV Higgs-like state in the context of a two-Higgs-doublet model with a heavy fourth sequential generation of fermions, in which one Higgs doublet couples only to the fourth-generation fermions, while the second doublet couples to the lighter fermions of the first three families. This model is designed to accommodate the apparent heaviness of the fourth-generation fermions and to effectively address the low-energy phenomenology of a dynamical electroweak-symmetry-breaking scenario. The physical Higgs states of the model are, therefore, viewed as composites primarily of the fourth-generation fermions. We find that the lightest Higgs, h, is a good candidate for the recently discovered 125 GeV spin-zero particle, when tanβ˜O(1), for typical fourth-generation fermion masses of M4G=400-600GeV, and with a large t-t' mixing in the right-handed quark sector. This, in turn, leads to BR(t'→th)˜O(1), which drastically changes the t' decay pattern. We also find that, based on the current Higgs data, this two-Higgs-doublet model generically predicts an enhanced production rate (compared to the Standard Model) in the pp→h→ττ channel, and reduced rates in the VV→h→γγ and pp¯/pp→V→hV→Vbb channels. Finally, the heavier CP-even Higgs is excluded by the current data up to mH˜500GeV, while the pseudoscalar state, A, can be as light as 130 GeV. These heavier Higgs states and the expected deviations from the Standard Model din some of the Higgs production channels can be further excluded or discovered with more data.
NASA Technical Reports Server (NTRS)
Nielsen, Eric J.; Kleb, William L.
2005-01-01
A methodology is developed and implemented to mitigate the lengthy software development cycle typically associated with constructing a discrete adjoint solver for aerodynamic simulations. The approach is based on a complex-variable formulation that enables straightforward differentiation of complicated real-valued functions. An automated scripting process is used to create the complex-variable form of the set of discrete equations. An efficient method for assembling the residual and cost function linearizations is developed. The accuracy of the implementation is verified through comparisons with a discrete direct method as well as a previously developed handcoded discrete adjoint approach. Comparisons are also shown for a large-scale configuration to establish the computational efficiency of the present scheme. To ultimately demonstrate the power of the approach, the implementation is extended to high temperature gas flows in chemical nonequilibrium. Finally, several fruitful research and development avenues enabled by the current work are suggested.
Efficient Construction of Discrete Adjoint Operators on Unstructured Grids Using Complex Variables
NASA Technical Reports Server (NTRS)
Nielsen, Eric J.; Kleb, William L.
2005-01-01
A methodology is developed and implemented to mitigate the lengthy software development cycle typically associated with constructing a discrete adjoint solver for aerodynamic simulations. The approach is based on a complex-variable formulation that enables straightforward differentiation of complicated real-valued functions. An automated scripting process is used to create the complex-variable form of the set of discrete equations. An efficient method for assembling the residual and cost function linearizations is developed. The accuracy of the implementation is verified through comparisons with a discrete direct method as well as a previously developed handcoded discrete adjoint approach. Comparisons are also shown for a large-scale configuration to establish the computational efficiency of the present scheme. To ultimately demonstrate the power of the approach, the implementation is extended to high temperature gas flows in chemical nonequilibrium. Finally, several fruitful research and development avenues enabled by the current work are suggested.
Adjoint equations and analysis of complex systems: Application to virus infection modelling
NASA Astrophysics Data System (ADS)
Marchuk, G. I.; Shutyaev, V.; Bocharov, G.
2005-12-01
Recent development of applied mathematics is characterized by ever increasing attempts to apply the modelling and computational approaches across various areas of the life sciences. The need for a rigorous analysis of the complex system dynamics in immunology has been recognized since more than three decades ago. The aim of the present paper is to draw attention to the method of adjoint equations. The methodology enables to obtain information about physical processes and examine the sensitivity of complex dynamical systems. This provides a basis for a better understanding of the causal relationships between the immune system's performance and its parameters and helps to improve the experimental design in the solution of applied problems. We show how the adjoint equations can be used to explain the changes in hepatitis B virus infection dynamics between individual patients.
An Exact Dual Adjoint Solution Method for Turbulent Flows on Unstructured Grids
NASA Technical Reports Server (NTRS)
Nielsen, Eric J.; Lu, James; Park, Michael A.; Darmofal, David L.
2003-01-01
An algorithm for solving the discrete adjoint system based on an unstructured-grid discretization of the Navier-Stokes equations is presented. The method is constructed such that an adjoint solution exactly dual to a direct differentiation approach is recovered at each time step, yielding a convergence rate which is asymptotically equivalent to that of the primal system. The new approach is implemented within a three-dimensional unstructured-grid framework and results are presented for inviscid, laminar, and turbulent flows. Improvements to the baseline solution algorithm, such as line-implicit relaxation and a tight coupling of the turbulence model, are also presented. By storing nearest-neighbor terms in the residual computation, the dual scheme is computationally efficient, while requiring twice the memory of the flow solution. The scheme is expected to have a broad impact on computational problems related to design optimization as well as error estimation and grid adaptation efforts.
Application of Adjoint Methodology to Supersonic Aircraft Design Using Reversed Equivalent Areas
NASA Technical Reports Server (NTRS)
Rallabhandi, Sriram K.
2013-01-01
This paper presents an approach to shape an aircraft to equivalent area based objectives using the discrete adjoint approach. Equivalent areas can be obtained either using reversed augmented Burgers equation or direct conversion of off-body pressures into equivalent area. Formal coupling with CFD allows computation of sensitivities of equivalent area objectives with respect to aircraft shape parameters. The exactness of the adjoint sensitivities is verified against derivatives obtained using the complex step approach. This methodology has the benefit of using designer-friendly equivalent areas in the shape design of low-boom aircraft. Shape optimization results with equivalent area cost functionals are discussed and further refined using ground loudness based objectives.
NASA Astrophysics Data System (ADS)
Kraft, S.; Puel, G.; Aubry, D.; Funfschilling, C.
2016-12-01
For the calibration of multi-body models of railway vehicles, the identification of the model parameters from on-track measurement is required. This involves the solution of an inverse problem by minimising the misfit function which describes the distance between model and measurement using optimisation methods. The application of gradient-based optimisation methods is advantageous but necessitates an efficient approach for the computation of the gradients considering the large number of model parameters and the costly evaluation of the forward model. This work shows that the application of the adjoint state approach to the nonlinear vehicle-track multi-body system is suitable, reducing on the one hand the computational cost and increasing on the other hand the precision of the gradients. Gradients from the adjoint state method are computed for vehicle models and validated taking into account measurement noise.
A Low-Order Galerkin Model Based on DMD and Adjoint-DMD modes
NASA Astrophysics Data System (ADS)
Zhang, Wei; Wei, Mingjun
2016-11-01
Dynamic Mode Decomposition (DMD) has emerged as a new tool for the understanding of flow dynamics associated with frequencies. The DMD modes computed by this process have been considered as an alternative of base functions for model order reduction. However, DMD modes are not orthogonal bases which are usually desired for the simplicity of Galerkin models. Therefore, we used the bi-orthogonal pair of DMD modes and adjoint DMD modes to solve this problem, and introduced an easy approach to derive a simple DMD-Galerkin projection model. The introduction of adjoint DMD modes also provides an easy way to rank DMD modes for order reduction. The approach is applied on a flow-passing-cylinder case in both transition and periodic stages. For the periodic case, DMD-Galerkin model is similar to POD-Galerkin model; and for the transition case, DMD-Galerkin model carries more clear frequency features. Supported by ARL.
NASA Astrophysics Data System (ADS)
Marcotte, Christopher D.; Grigoriev, Roman O.
2016-09-01
This paper introduces a numerical method for computing the spectrum of adjoint (left) eigenfunctions of spiral wave solutions to reaction-diffusion systems in arbitrary geometries. The method is illustrated by computing over a hundred eigenfunctions associated with an unstable time-periodic single-spiral solution of the Karma model on a square domain. We show that all leading adjoint eigenfunctions are exponentially localized in the vicinity of the spiral tip, although the marginal modes (response functions) demonstrate the strongest localization. We also discuss the implications of the localization for the dynamics and control of unstable spiral waves. In particular, the interaction with no-flux boundaries leads to a drift of spiral waves which can be understood with the help of the response functions.
Got a Minute? Which Higgs did we find?
Stupak, John
2016-07-12
Dr. John Stupak talks about the discovery of the Higgs boson. Did scientists find the Higgs boson predicted back in 1964 or did they find just one of a group of particles, with the others still to be found?
Models of little Higgs and electroweak precision tests
Chen, Mu-Chun; /Fermilab
2006-01-01
The little Higgs idea is an alternative to supersymmetry as a solution to the gauge hierarchy problem. In this note, the author reviews various little Higgs models and their phenomenology with emphasis on the precision electroweak constraints in these models.
Got a Minute? Which Higgs did we find?
Stupak, John
2014-06-26
Dr. John Stupak talks about the discovery of the Higgs boson. Did scientists find the Higgs boson predicted back in 1964 or did they find just one of a group of particles, with the others still to be found?
Adjoint-Free Variational Data Assimilation into a Regional Wave Model
2015-07-01
algorithm assimilating HFR data was ex- ecuted in 74 s on a single processor . A series of OI and a4DVAR experiments were con- ducted, involving assimilation...Adjoint-Free Variational Data Assimilation into a Regional Wave Model GLEB PANTELEEV University of Alaska Fairbanks, Fairbanks, Alaska, and National...Manuscript received 12 September 2014, in final form 23 December 2014) ABSTRACT A variational data assimilation algorithm is developed for the ocean
Adjoint-based uncertainty quantification and sensitivity analysis for reactor depletion calculations
NASA Astrophysics Data System (ADS)
Stripling, Hayes Franklin
Depletion calculations for nuclear reactors model the dynamic coupling between the material composition and neutron flux and help predict reactor performance and safety characteristics. In order to be trusted as reliable predictive tools and inputs to licensing and operational decisions, the simulations must include an accurate and holistic quantification of errors and uncertainties in its outputs. Uncertainty quantification is a formidable challenge in large, realistic reactor models because of the large number of unknowns and myriad sources of uncertainty and error. We present a framework for performing efficient uncertainty quantification in depletion problems using an adjoint approach, with emphasis on high-fidelity calculations using advanced massively parallel computing architectures. This approach calls for a solution to two systems of equations: (a) the forward, engineering system that models the reactor, and (b) the adjoint system, which is mathematically related to but different from the forward system. We use the solutions of these systems to produce sensitivity and error estimates at a cost that does not grow rapidly with the number of uncertain inputs. We present the framework in a general fashion and apply it to both the source-driven and k-eigenvalue forms of the depletion equations. We describe the implementation and verification of solvers for the forward and ad- joint equations in the PDT code, and we test the algorithms on realistic reactor analysis problems. We demonstrate a new approach for reducing the memory and I/O demands on the host machine, which can be overwhelming for typical adjoint algorithms. Our conclusion is that adjoint depletion calculations using full transport solutions are not only computationally tractable, they are the most attractive option for performing uncertainty quantification on high-fidelity reactor analysis problems.
Seismic wave-speed structure beneath the metropolitan area of Japan based on adjoint tomography
NASA Astrophysics Data System (ADS)
Miyoshi, T.; Obayashi, M.; Tono, Y.; Tsuboi, S.
2015-12-01
We have obtained a three-dimensional (3D) model of seismic wave-speed structure beneath the metropolitan area of Japan. We applied the spectral-element method (e.g. Komatitsch and Tromp 1999) and adjoint method (Liu and Tromp 2006) to the broadband seismograms in order to infer the 3D model. We used the travel-time tomography result (Matsubara and Obara 2011) as an initial 3D model and used broadband waveforms recorded at the NIED F-net stations. We selected 147 earthquakes with magnitude of larger than 4.5 from the F-net earthquake catalog and used their bandpass filtered seismograms between 5 and 20 second with a high S/N ratio. The 3D model used for the forward and adjoint simulations is represented as a region of approximately 500 by 450 km in horizontal and 120 km in depth. Minimum period of theoretical waveforms was 4.35 second. For the adjoint inversion, we picked up the windows of the body waves from the observed and theoretical seismograms. We used SPECFEM3D_Cartesian code (e.g. Peter et al. 2011) for the forward and adjoint simulations, and their simulations were implemented by K-computer in RIKEN. Each iteration required about 0.1 million CPU hours at least. The model parameters of Vp and Vs were updated by using the steepest descent method. We obtained the fourth iterative model (M04), which reproduced observed waveforms better than the initial model. The shear wave-speed of M04 was significantly smaller than the initial model at any depth. The model of compressional wave-speed was not improved by inversion because of small alpha kernel values. Acknowledgements: This research was partly supported by MEXT Strategic Program for Innovative Research. We thank to the NIED for providing seismological data.
Parallelized Three-Dimensional Resistivity Inversion Using Finite Elements And Adjoint State Methods
NASA Astrophysics Data System (ADS)
Schaa, Ralf; Gross, Lutz; Du Plessis, Jaco
2015-04-01
The resistivity method is one of the oldest geophysical exploration methods, which employs one pair of electrodes to inject current into the ground and one or more pairs of electrodes to measure the electrical potential difference. The potential difference is a non-linear function of the subsurface resistivity distribution described by an elliptic partial differential equation (PDE) of the Poisson type. Inversion of measured potentials solves for the subsurface resistivity represented by PDE coefficients. With increasing advances in multichannel resistivity acquisition systems (systems with more than 60 channels and full waveform recording are now emerging), inversion software require efficient storage and solver algorithms. We developed the finite element solver Escript, which provides a user-friendly programming environment in Python to solve large-scale PDE-based problems (see https://launchpad.net/escript-finley). Using finite elements, highly irregular shaped geology and topography can readily be taken into account. For the 3D resistivity problem, we have implemented the secondary potential approach, where the PDE is decomposed into a primary potential caused by the source current and the secondary potential caused by changes in subsurface resistivity. The primary potential is calculated analytically, and the boundary value problem for the secondary potential is solved using nodal finite elements. This approach removes the singularity caused by the source currents and provides more accurate 3D resistivity models. To solve the inversion problem we apply a 'first optimize then discretize' approach using the quasi-Newton scheme in form of the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) method (see Gross & Kemp 2013). The evaluation of the cost function requires the solution of the secondary potential PDE for each source current and the solution of the corresponding adjoint-state PDE for the cost function gradients with respect to the subsurface
Neural network training by integration of adjoint systems of equations forward in time
NASA Technical Reports Server (NTRS)
Toomarian, Nikzad (Inventor); Barhen, Jacob (Inventor)
1992-01-01
A method and apparatus for supervised neural learning of time dependent trajectories exploits the concepts of adjoint operators to enable computation of the gradient of an objective functional with respect to the various parameters of the network architecture in a highly efficient manner. Specifically, it combines the advantage of dramatic reductions in computational complexity inherent in adjoint methods with the ability to solve two adjoint systems of equations together forward in time. Not only is a large amount of computation and storage saved, but the handling of real-time applications becomes also possible. The invention has been applied it to two examples of representative complexity which have recently been analyzed in the open literature and demonstrated that a circular trajectory can be learned in approximately 200 iterations compared to the 12000 reported in the literature. A figure eight trajectory was achieved in under 500 iterations compared to 20000 previously required. The trajectories computed using our new method are much closer to the target trajectories than was reported in previous studies.
Towards efficient backward-in-time adjoint computations using data compression techniques
Cyr, E. C.; Shadid, J. N.; Wildey, T.
2014-12-16
In the context of a posteriori error estimation for nonlinear time-dependent partial differential equations, the state-of-the-practice is to use adjoint approaches which require the solution of a backward-in-time problem defined by a linearization of the forward problem. One of the major obstacles in the practical application of these approaches, we found, is the need to store, or recompute, the forward solution to define the adjoint problem and to evaluate the error representation. Our study considers the use of data compression techniques to approximate forward solutions employed in the backward-in-time integration. The development derives an error representation that accounts for themore » difference between the standard-approach and the compressed approximation of the forward solution. This representation is algorithmically similar to the standard representation and only requires the computation of the quantity of interest for the forward solution and the data-compressed reconstructed solution (i.e. scalar quantities that can be evaluated as the forward problem is integrated). This approach is then compared with existing techniques, such as checkpointing and time-averaged adjoints. Lastly, we provide numerical results indicating the potential efficiency of our approach on a transient diffusion–reaction equation and on the Navier–Stokes equations. These results demonstrate memory compression ratios up to 450×450× while maintaining reasonable accuracy in the error-estimates.« less
Neural Network Training by Integration of Adjoint Systems of Equations Forward in Time
NASA Technical Reports Server (NTRS)
Toomarian, Nikzad (Inventor); Barhen, Jacob (Inventor)
1999-01-01
A method and apparatus for supervised neural learning of time dependent trajectories exploits the concepts of adjoint operators to enable computation of the gradient of an objective functional with respect to the various parameters of the network architecture in a highly efficient manner. Specifically. it combines the advantage of dramatic reductions in computational complexity inherent in adjoint methods with the ability to solve two adjoint systems of equations together forward in time. Not only is a large amount of computation and storage saved. but the handling of real-time applications becomes also possible. The invention has been applied it to two examples of representative complexity which have recently been analyzed in the open literature and demonstrated that a circular trajectory can be learned in approximately 200 iterations compared to the 12000 reported in the literature. A figure eight trajectory was achieved in under 500 iterations compared to 20000 previously required. Tbc trajectories computed using our new method are much closer to the target trajectories than was reported in previous studies.
Minimal Composite Higgs Models at the LHC
Carena, Marcela; Da Rold, Leandro; Pontón, Eduardo
2014-06-26
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) → SO(4) symmetry breaking pattern, assuming the “partial compositeness” paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the Z b ¯ b coupling, i.e. the 5, 10 and 14. We findmore » a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.« less
The Higgs Boson Search and Discovery
NASA Astrophysics Data System (ADS)
Bernardi, Gregorio; Konigsberg, Jacobo
2016-10-01
We present a brief account of the search for the Higgs boson at the three major colliders that have operated over the last three decades: LEP, the Tevatron, and the LHC. The experimental challenges encountered stemmed from the distinct event phenomenology as determined by the colliders energy and the possible values for the Higgs boson mass, and from the capability of these colliders to deliver as much collision data as possible to fully explore the mass spectrum within their reach. Focusing more on the hadron collider searches during the last decade, we discuss how the search for the Higgs boson was advanced through mastering the experimental signatures of standard theory backgrounds, through the comprehensive utilization of the features of the detectors involved in the searches, and by means of advanced data analysis techniques. The search culminated in 2012 with the discovery, by the ATLAS and CMS collaborations, of a Higgs-like particle with mass close to 125 GeV, confirmed more recently to have properties consistent with those expected from the standard theory Higgs boson.
The flavor of the Composite Twin Higgs
NASA Astrophysics Data System (ADS)
Csáki, Csaba; Geller, Michael; Telem, Ofri; Weiler, Andreas
2016-09-01
The assumption of anarchic quark flavor puts serious stress on composite Higgs models: flavor bounds imply a tuning of a few per-mille (at best) in the Higgs potential. Composite twin Higgs (CTH) models significantly reduce this tension by opening up a new region of parameter space, obtained by raising the coupling among the composites close to the strong coupling limit g ∗ ˜ 4π, thereby raising the scale of composites to around 10 TeV. This does not lead to large tuning in the Higgs potential since the leading quantum corrections are canceled by the twin partners (rather than the composites). We survey the leading flavor bounds on the CTH, which correspond to tree-level Δ F = 2 four-Fermi operators from Kaluza-Klein (KK) Z exchange in the kaon system and 1-loop corrections from KK fermions to the electric dipole moment of the neutron. We provide a parametric estimate for these bounds and also perform a numeric scan of the parameter space using the complete calculation for both quantities. The results confirm our expectation that CTH models accommodate anarchic flavor significantly better than regular composite Higgs (CH) models. Our conclusions apply both to the identical and fraternal twin cases.
Probing triple Higgs couplings of the two Higgs doublet model at a linear collider
Arhrib, Abdesslam; Benbrik, Rachid; Chiang, C.-W.
2008-06-01
We study double Higgs production at the future linear collider in the framework of the two Higgs doublet models through the following channels: e{sup +}e{sup -}{yields}{phi}{sub i}{phi}{sub j}Z, {phi}{sub i}=h{sup 0}, H{sup 0}, A{sup 0}, H{sup {+-}}. All these processes are sensitive to triple Higgs couplings. Hence observations of them provide information on the triple Higgs couplings that help reconstructing the scalar potential. We also discuss the double Higgs-Strahlung e{sup +}e{sup -}{yields}h{sup 0}h{sup 0}Z in the decoupling limit where h{sup 0} mimics the standard model Higgs boson. The processes e{sup +}e{sup -}{yields}h{sup 0}h{sup 0}Z and e{sup +}e{sup -}{yields}h{sup 0}H{sup 0}Z are also discussed in the fermiophobic limit where distinctive signatures such as 4{gamma}+X, 2{gamma}+X, and 6{gamma}+X are expected in the Type-I two Higgs doublet model.
Neutral Higgs boson pair production in photon-photon annihilation in the two Higgs doublet model
Arhrib, Abdesslam; Benbrik, Rachid; Chen, C.-H.; Santos, Rui
2009-07-01
We study double Higgs production in photon-photon collisions as a probe of the new dynamics of Higgs interactions in the framework of two Higgs doublet models. We analyze neutral Higgs bosons production and decay in the fusion processes, {gamma}{gamma}{yields}S{sub i}S{sub j}, S{sub i}=h{sup 0}, H{sup 0}, A{sup 0}, and show that both h{sup 0}h{sup 0} and A{sup 0}A{sup 0} production can be enhanced by threshold effects in the region E{sub {gamma}}{sub {gamma}}{approx_equal}2m{sub H{+-}}. Resonant effects due to the heavy Higgs H{sup 0} can also play a role in the cross section enhancement when it is allowed to decay to two light CP-even h{sup 0} or to two light CP-odd A{sup 0} scalars. We have scanned the allowed parameter space of the two Higgs doublet model and found a vast region of the parameter space where the cross section is 2 orders of magnitude above the standard model cross section. We further show that the standard model experimental analysis can be used to discover or to constrain the two Higgs doublet model parameter space.
A light Higgs scalar in the NMSSM confronted with the latest LHC Higgs data
NASA Astrophysics Data System (ADS)
Cao, Junjie; Ding, Fangfang; Han, Chengcheng; Yang, Jin Min; Zhu, Jingya
2013-11-01
In the Next-to-Minimal Supersymemtric Standard Model (NMSSM), one of the neutral Higgs scalars (CP-even or CP-odd) may be lighter than half of the SM-like Higgs boson. In this case, the SM-like Higgs boson h can decay into such a light scalar pair and consequently the γγ and ZZ * signal rates at the LHC will be suppressed. In this work, we examine the constraints of the latest LHC Higgs data on such a possibility. We perform a comprehensive scan over the parameter space of the NMSSM by considering various experimental constraints and find that the LHC Higgs data can readily constrain the parameter space and the properties of the light scalar, e.g., at 3 σ level this light scalar should be highly singlet dominant and the branching ratio of the SM-like Higgs boson decay into the scalar pair should be less than 30%. Also we investigate the detection of this scalar at various colliders. Through a detailed Monte Carlo simulation we find that under the constraints of the current Higgs data this light scalar can be accessible at the LHC-14 with an integrated luminosity over 300 fb-1.
Search for heavy neutral MSSM Higgs bosons with CMS: reach and Higgs mass precision
NASA Astrophysics Data System (ADS)
Gennai, S.; Heinemeyer, S.; Kalinowski, A.; Kinnunen, R.; Lehti, S.; Nikitenko, A.; Weiglein, G.
2007-10-01
The search for MSSM Higgs bosons will be an important goal at the LHC. We analyze the search reach of the CMS experiment for the heavy neutral MSSM Higgs bosons with an integrated luminosity of 30 or 60 fb-1. This is done by combining the latest results for the CMS experimental sensitivities based on full simulation studies with state-of-the-art theoretical predictions of the MSSM Higgs-boson properties. The results are interpreted in MSSM benchmark scenarios in terms of the parameters tan β and the Higgs-boson mass scale, MA. We study the dependence of the 5σ discovery contours in the MA tan β plane on variations of the other supersymmetric parameters. The largest effects arise from a change in the higgsino mass parameter μ, which enters both via higher-order radiative corrections and via the kinematics of Higgs decays into supersymmetric particles. While the variation of μ can shift the prospective discovery reach (and correspondingly the ”LHC wedge” region) by about Δtan β=10, we find that the discovery reach is rather stable with respect to the impact of other supersymmetric parameters. Within the discovery region we analyze the accuracy with which the masses of the heavy neutral Higgs bosons can be determined. We find that an accuracy of 1 4% should be achievable, which could make it possible in favorable regions of the MSSM parameter space to experimentally resolve the signals of the two heavy MSSM Higgs bosons at the LHC.
Higgs decays in gauge extensions of the standard model
NASA Astrophysics Data System (ADS)
Bunk, Don; Hubisz, Jay; Jain, Bithika
2014-02-01
We explore the phenomenology of virtual spin-1 contributions to the h→γγ and h→Zγ decay rates in gauge extensions of the standard model. We consider generic Lorentz and gauge-invariant vector self-interactions, which can have nontrivial structure after diagonalizing the quadratic part of the action. Such features are phenomenologically relevant in models where the electroweak gauge bosons mix with additional spin-1 fields, such as occurs in little Higgs models, extra dimensional models, strongly coupled variants of electroweak symmetry breaking, and other gauge extensions of the standard model. In models where nonrenormalizable operators mix field strengths of gauge groups, the one-loop Higgs decay amplitudes can be logarithmically divergent, and we provide power counting for the size of the relevant counterterm. We provide an example calculation in a four-site moose model that contains degrees of freedom that model the effects of vector and axial-vector resonances arising from TeV scale strong dynamics.
Investigating Sensitivity to Saharan Dust in Tropical Cyclone Formation Using Nasa's Adjoint Model
NASA Technical Reports Server (NTRS)
Holdaway, Daniel
2015-01-01
As tropical cyclones develop from easterly waves coming of the coast of Africa they interact with dust from the Sahara desert. There is a long standing debate over whether this dust inhibits or advances the developing storm and how much influence it has. Dust can surround the storm and absorb incoming solar radiation, cooling the air below. As a result an energy source for the system is potentially diminished, inhibiting growth of the storm. Alternatively dust may interact with clouds through micro-physical processes, for example by causing more moisture to condense, potentially increasing the strength. As a result of climate change, concentrations and amount of dust in the atmosphere will likely change. It it is important to properly understand its effect on tropical storm formation. The adjoint of an atmospheric general circulation model provides a very powerful tool for investigating sensitivity to initial conditions. The National Aeronautics and Space Administration (NASA) has recently developed an adjoint version of the Goddard Earth Observing System version 5 (GEOS-5) dynamical core, convection scheme, cloud model and radiation schemes. This is extended so that the interaction between dust and radiation is also accounted for in the adjoint model. This provides a framework for examining the sensitivity to dust in the initial conditions. Specifically the set up allows for an investigation into the extent to which dust affects cyclone strength through absorption of radiation. In this work we investigate the validity of using an adjoint model for examining sensitivity to dust in hurricane formation. We present sensitivity results for a number of systems that developed during the Atlantic hurricane season of 2006. During this period there was a significant outbreak of Saharan dust and it is has been argued that this outbreak was responsible for the relatively calm season. This period was also covered by an extensive observation campaign. It is shown that the
Investigating sensitivity to Saharan dust in tropical cyclone formation using NASA's adjoint model
NASA Astrophysics Data System (ADS)
Holdaway, Daniel
2015-04-01
As tropical cyclones develop from easterly waves coming off the coast of Africa they interact with dust from the Sahara desert. There is a long standing debate over whether this dust inhibits or advances the developing storm and how much influence it has. Dust can surround the storm and absorb incoming solar radiation, cooling the air below. As a result an energy source for the system is potentially diminished, inhibiting growth of the storm. Alternatively dust may interact with clouds through micro-physical processes, for example by causing more moisture to condense, potentially increasing the strength. As a result of climate change, concentrations and amount of dust in the atmosphere will likely change. It it is important to properly understand its effect on tropical storm formation. The adjoint of an atmospheric general circulation model provides a very powerful tool for investigating sensitivity to initial conditions. The National Aeronautics and Space Administration (NASA) has recently developed an adjoint version of the Goddard Earth Observing System version 5 (GEOS-5) dynamical core, convection scheme, cloud model and radiation schemes. This is extended so that the interaction between dust and radiation is also accounted for in the adjoint model. This provides a framework for examining the sensitivity to dust in the initial conditions. Specifically the set up allows for an investigation into the extent to which dust affects cyclone strength through absorption of radiation. In this work we investigate the validity of using an adjoint model for examining sensitivity to dust in hurricane formation. We present sensitivity results for a number of systems that developed during the Atlantic hurricane season of 2006. During this period there was a significant outbreak of Saharan dust and it is has been argued that this outbreak was responsible for the relatively calm season. This period was also covered by an extensive observation campaign. It is shown that the
Reentry-Vehicle Shape Optimization Using a Cartesian Adjoint Method and CAD Geometry
NASA Technical Reports Server (NTRS)
Nemec, Marian; Aftosmis, Michael J.
2006-01-01
A DJOINT solutions of the governing flow equations are becoming increasingly important for the development of efficient analysis and optimization algorithms. A well-known use of the adjoint method is gradient-based shape. Given an objective function that defines some measure of performance, such as the lift and drag functionals, its gradient is computed at a cost that is essentially independent of the number of design variables (e.g., geometric parameters that control the shape). Classic aerodynamic applications of gradient-based optimization include the design of cruise configurations for transonic and supersonic flow, as well as the design of high-lift systems. are perhaps the most promising approach for addressing the issues of flow solution automation for aerodynamic design problems. In these methods, the discretization of the wetted surface is decoupled from that of the volume mesh. This not only enables fast and robust mesh generation for geometry of arbitrary complexity, but also facilitates access to geometry modeling and manipulation using parametric computer-aided design (CAD). In previous work on Cartesian adjoint solvers, Melvin et al. developed an adjoint formulation for the TRANAIR code, which is based on the full-potential equation with viscous corrections. More recently, Dadone and Grossman presented an adjoint formulation for the two-dimensional Euler equations using a ghost-cell method to enforce the wall boundary conditions. In Refs. 18 and 19, we presented an accurate and efficient algorithm for the solution of the adjoint Euler equations discretized on Cartesian meshes with embedded, cut-cell boundaries. Novel aspects of the algorithm were the computation of surface shape sensitivities for triangulations based on parametric-CAD models and the linearization of the coupling between the surface triangulation and the cut-cells. The accuracy of the gradient computation was verified using several three-dimensional test cases, which included design
Analytic one-loop amplitudes for a Higgs boson plus four partons
Dixon, Lance J.; Sofianatos, Yorgos; /SLAC
2009-06-02
We compute the one-loop QCD amplitudes for the processes H{anti q}q{anti Q}Q and H{anti q}qgg, the latter restricted to the case of opposite-helicity gluons. Analytic expressions are presented for the color- and helicity-decomposed amplitudes. The coupling of the Higgs boson to gluons is treated by an effective interaction in the limit of large top quark mass. The Higgs field is split into a complex field {phi} and its complex conjugate {phi}{sup {dagger}}. The split is useful because amplitudes involving {phi} have different analytic structure from those involving {phi}{sup {dagger}}. We compute the cut-containing pieces of the amplitudes using generalized unitarity. The remaining rational parts are obtained by on-shell recursion. Our results for H{anti q}q{anti Q}Q agree with previous semi-numerical computations. We also show how to convert existing semi-numerical results for the production of a scalar Higgs boson into analogous results for a pseudoscalar Higgs boson.
An extended standard model and its Higgs geometry from the matrix model
NASA Astrophysics Data System (ADS)
Steinacker, Harold C.; Zahn, Jochen
2014-08-01
We find a simple brane configuration in the IKKT matrix model which resembles the standard model at low energies, with a second Higgs doublet and right-handed neutrinos. The electroweak sector is realized geometrically in terms of two minimal fuzzy ellipsoids, which can be interpreted in terms of four point-branes in the extra dimensions. The electroweak Higgs connects these branes and is an indispensable part of the geometry. Fermionic would-be zero modes arise at the intersections with two larger branes, leading precisely to the correct chiral matter fields at low energy, along with right-handed neutrinos which can acquire a Majorana mass due to a Higgs singlet. The larger branes give rise to SU(3)_c, extended by U(1)_B and another U(1) which are anomalous at low energies and expected to disappear. At higher energies, mirror fermions and additional fields arise, completing the full {N}=4 supersymmetry. The brane configuration is a solution of the model, assuming a suitable effective potential and a non-linear stabilization of the singlet Higgs. The basic results can be carried over to {N}=4 SU(N) super Yang-Mills on ordinary Minkowski space with sufficiently large N.
Beyond the standard Higgs after the 125 GeV Higgs discovery
Grojean, C.
2015-01-01
An elementary, weakly coupled and solitary Higgs boson allows one to extend the validity of the Standard Model up to very high energy, maybe as high as the Planck scale. Nonetheless, this scenario fails to fill the universe with dark matter and does not explain the matter–antimatter asymmetry. However, amending the Standard Model tends to destabilize the weak scale by large quantum corrections to the Higgs potential. New degrees of freedom, new forces, new organizing principles are required to provide a consistent and natural description of physics beyond the standard Higgs.
Search for a lighter Higgs boson in Two Higgs Doublet Models
NASA Astrophysics Data System (ADS)
Cacciapaglia, Giacomo; Deandrea, Aldo; Gascon-Shotkin, Suzanne; Le Corre, Solène; Lethuillier, Morgan; Tao, Junquan
2016-12-01
We consider present constraints on Two Higgs Doublet Models, both from the LHC at Run 1 and from other sources in order to explore the possibility of constraining a neutral scalar or pseudo-scalar particle lighter than the 125 GeV Higgs boson. Such a lighter particle is not yet completely excluded by present data. We show with a simplified analysis that some new constraints could be obtained at the LHC if such a search is performed by the experimental collaborations, which we therefore encourage to continue carrying out light diphoton resonance searches at √{s}=13 TeV in the context of Two Higgs Doublet Models.
Heberton, C.I.; Russell, T.F.; Konikow, L.F.; Hornberger, G.Z.
2000-01-01
This report documents the U.S. Geological Survey Eulerian-Lagrangian Localized Adjoint Method (ELLAM) algorithm that solves an integral form of the solute-transport equation, incorporating an implicit-in-time difference approximation for the dispersive and sink terms. Like the algorithm in the original version of the U.S. Geological Survey MOC3D transport model, ELLAM uses a method of characteristics approach to solve the transport equation on the basis of the velocity field. The ELLAM algorithm, however, is based on an integral formulation of conservation of mass and uses appropriate numerical techniques to obtain global conservation of mass. The implicit procedure eliminates several stability criteria required for an explicit formulation. Consequently, ELLAM allows large transport time increments to be used. ELLAM can produce qualitatively good results using a small number of transport time steps. A description of the ELLAM numerical method, the data-input requirements and output options, and the results of simulator testing and evaluation are presented. The ELLAM algorithm was evaluated for the same set of problems used to test and evaluate Version 1 and Version 2 of MOC3D. These test results indicate that ELLAM offers a viable alternative to the explicit and implicit solvers in MOC3D. Its use is desirable when mass balance is imperative or a fast, qualitative model result is needed. Although accurate solutions can be generated using ELLAM, its efficiency relative to the two previously documented solution algorithms is problem dependent.
NASA Astrophysics Data System (ADS)
Horbach, A.; Bunge, H.-P.
2012-04-01
Forward simulations of mantle circulation processes in the Earth's interior suffer from the problem of an unknown initial condition, that is the temperature distribution of the past is not known a-priori. With the help of the adjoint method (Bunge (2003)), we are able to determine an optimal initial condition iteratively, given a temperature model of the present time. Here we use an s-wave tomography (Grand (1997)) as the estimator for present-day Earth structure. The seismic model is converted into temperature using a published self-consistent mineralogical model (Piazzoni (2007)), allowing us to constrain a time series of mantle flow consistent with the present-day estimator for the past 40 Myrs. Temperature fluctuations initiate density anomalies, which in turn influence the Earth's external gravitational field. Gravity provides an important constraint for geodynamic modelling. We find a very high correlation of our model geoid for the present time to current satellite derived geoid solutions. Furthermore, our models of paleo circulation allow us to determine time-series of the geoid for the past 40 Ma. Some remarkable geodynamic features can be recognized from our proof-of-concept models, especially the sinking of the Farallon and the Tethys slab through the Earth's mantle, and their associated effects on past topography and geoid.
Ian Hinchliffe Answers Your Higgs Boson Questions
Hinchliffe, Ian
2012-01-01
contingent with the ATLAS experiment at CERN, answers many of your questions about the Higgs boson. Ian invited viewers to send in questions about the Higgs via email, Twitter, Facebook, or YouTube in an "Ask a Scientist" video posted July 3: http://youtu.be/xhuA3wCg06s CERN's July 4 announcement that the ATLAS and CMS experiments at the Large Hadron Collider have discovered a particle "consistent with the Higgs boson" has raised questions about what scientists have found and what still remains to be found -- and what it all means. If you have suggestions for future "Ask a Scientist" videos, post them below or send ideas to askascientist@lbl.gov
Searching for displaced Higgs boson decays
NASA Astrophysics Data System (ADS)
Csáki, Csaba; Kuflik, Eric; Lombardo, Salvator; Slone, Oren
2015-10-01
We study a simplified model of the Standard Model (SM) Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs boson decays below 10 cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at √{s }=13 TeV . With 20 fb-1 of data, we find that Higgs branching ratios down to 2 ×1 0-4 can be probed for centimeter decay lengths.
Dissertori, G
2015-01-13
Enormous efforts at accelerators and experiments all around the world have gone into the search for the long-sought Higgs boson, postulated almost five decades ago. This search has culminated in the discovery of a Higgs-like particle by the ATLAS and CMS experiments at CERN's Large Hadron Collider in 2012. Instead of describing this widely celebrated discovery, in this article I will rather focus on earlier attempts to discover the Higgs boson, or to constrain the range of possible masses by interpreting precise data in the context of the Standard Model of particle physics. In particular, I will focus on the experimental efforts carried out during the last two decades, at the Large Electron Positron collider, CERN, Geneva, Switzerland, and the Tevatron collider, Fermilab, near Chicago, IL, USA.
Charged Particle Optics in Circular Higgs Factory
Cai, Yunhai
2015-02-26
Similar to a super B-factory, a circular Higgs factory will require strong focusing systems near the interaction points and a low-emittance lattice in arcs to achieve a factory luminosity. At electron beam energy of 120 GeV, beamstrahlung effects during the collision pose an additional challenge to the collider design. In particular, a large momentum acceptance at 2 percent level is necessary to retain an adequate beam lifetime. This turns out to be the most challenging aspect in the design of circular Higgs factory. In this paper, an example will be provided to illustrate the beam dynamics in circular Higgs factory, emphasizing on the chromatic optics. Basic optical modules and advanced analysis will be presented. Most important, we will show that 2% momentum aperture is achievable
Ian Hinchliffe Answers Your Higgs Boson Questions
Hinchliffe, Ian
2016-07-12
contingent with the ATLAS experiment at CERN, answers many of your questions about the Higgs boson. Ian invited viewers to send in questions about the Higgs via email, Twitter, Facebook, or YouTube in an "Ask a Scientist" video posted July 3: http://youtu.be/xhuA3wCg06s CERN's July 4 announcement that the ATLAS and CMS experiments at the Large Hadron Collider have discovered a particle "consistent with the Higgs boson" has raised questions about what scientists have found and what still remains to be found -- and what it all means. If you have suggestions for future "Ask a Scientist" videos, post them below or send ideas to askascientist@lbl.gov
Definition of magnetic monopole numbers for SU(N) lattice gauge-Higgs models
NASA Astrophysics Data System (ADS)
Hollands, S.; Müller-Preussker, M.
2001-05-01
A geometric definition for a magnetic charge of Abelian monopoles in SU(N) lattice gauge theories with Higgs fields is presented. The corresponding local monopole number defined for almost all field configurations does not require gauge fixing and is stable against small perturbations. Its topological content is that of a three-cochain. A detailed prescription for calculating the local monopole number is worked out. Our method generalizes a magnetic charge definition previously invented by Phillips and Stone for SU(2).