Science.gov

Sample records for one-loop scalar pentagon

  1. ONELOOP: For the evaluation of one-loop scalar functions

    NASA Astrophysics Data System (ADS)

    van Hameren, A.

    2011-11-01

    ONELOOP is a program to evaluate the one-loop scalar 1-point, 2-point, 3-point and 4-point functions, for all kinematical configurations relevant for collider-physics, and for any non-positive imaginary parts of the internal squared masses. It deals with all UV and IR divergences within dimensional regularization. Furthermore, it provides routines to evaluate these functions using straightforward numerical integration. Program summaryProgram title: OneLOop Catalogue identifier: AEJO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 12 061 No. of bytes in distributed program, including test data, etc.: 74 163 Distribution format: tar.gz Programming language: Fortran Computer: Workstations Operating system: Linux, Unix RAM: Negligible Classification: 4.4, 11.1 Nature of problem: In order to reach next-to-leading order precision in the calculation of cross sections of hard scattering processes, one-loop amplitudes have to be evaluated. This is done by expressing them as linear combination of one-loop scalar functions. In a concrete calculation, these functions eventually have to be evaluated. If the scattering process involves unstable particles, consistency requires the evaluation of these functions with complex internal masses. Solution method: Expressions for the one-loop scalar functions in terms of single-variable analytic functions existing in literature have been implemented. Restrictions: The applicability is restricted to the kinematics occurring in collider-physics. Running time: The evaluation of the most general 4-point function with 4 complex masses takes about 180 μs, and the evaluation of the 4-point function with 4 real masses takes about 18 μs on a 2.80 GHz Intel Xeon processor.

  2. All one-loop scalar vertices in the effective potential approach

    NASA Astrophysics Data System (ADS)

    Camargo-Molina, José Eliel; Morais, António P.; Pasechnik, Roman; Sampaio, Marco O. P.; Wessén, Jonas

    2016-08-01

    Using the one-loop Coleman-Weinberg effective potential, we derive a general analytic expression for all the derivatives of the effective potential with respect to any number of classical scalar fields. The result is valid for a renormalisable theory in four dimensions with any number of scalars, fermions or gauge bosons. This result corresponds to the zero-external momentum contribution to a general one-loop diagram with N scalar external legs. We illustrate the use of the general result in two simple scalar singlet extensions of the Standard Model, to obtain the dominant contributions to the triple couplings of light scalar particles under the zero external momentum approximation.

  3. One-loop pentagon integral in d dimensions from differential equations in ɛ-form

    NASA Astrophysics Data System (ADS)

    Kozlov, Mikhail G.; Lee, Roman N.

    2016-02-01

    We apply the differential equation technique to the calculation of the one-loop massless diagram with five onshell legs. Using the reduction to ɛ-form, we manage to obtain a simple one-fold integral representation exact in space-time dimensionality. The expansion of the obtained result in ɛ and the analytical continuation to physical regions are discussed.

  4. High-temperature expansion of the one-loop free energy of a scalar field on a curved background

    NASA Astrophysics Data System (ADS)

    Kalinichenko, I. S.; Kazinski, P. O.

    2013-04-01

    The complete form of the high-temperature expansion of the one-loop contribution to the free energy of a scalar field on a stationary gravitational background is derived. The explicit expressions for the divergent and finite parts of the high-temperature expansion in a three-dimensional space without boundaries are obtained. These formulas generalize the known one for the stationary spacetime. In particular, we confirm that for a massless conformal scalar field the leading correction to the Planck law proportional to the temperature squared turns out to be nonzero due to the nonstatic nature of the metric. The explicit expression for the so-called energy-time anomaly is found. The interrelation between this anomaly and the conformal (trace) anomaly is established. The natural simplest Lagrangian for the “Killing vector field” is given.

  5. On a family of (1+1)-dimensional scalar field theory models: Kinks, stability, one-loop mass shifts

    SciTech Connect

    Alonso-Izquierdo, A.; Mateos Guilarte, J.

    2012-09-15

    In this paper we construct a one-parametric family of (1+1)-dimensional one-component scalar field theory models supporting kinks. Inspired by the sine-Gordon and {phi}{sup 4} models, we look at all possible extensions such that the kink second-order fluctuation operators are Schroedinger differential operators with Poeschl-Teller potential wells. In this situation, the associated spectral problem is solvable and therefore we shall succeed in analyzing the kink stability completely and in computing the one-loop quantum correction to the kink mass exactly. When the parameter is a natural number, the family becomes the hierarchy for which the potential wells are reflectionless, the two first levels of the hierarchy being the sine-Gordon and {phi}{sup 4} models. - Highlights: Black-Right-Pointing-Pointer We construct a family of scalar field theory models supporting kinks. Black-Right-Pointing-Pointer The second-order kink fluctuation operators involve Poeschl-Teller potential wells. Black-Right-Pointing-Pointer We compute the one-loop quantum correction to the kink mass with different methods.

  6. Non-perturbative corrections to the one-loop free energy induced by a massive scalar field on a stationary slowly varying in space gravitational background

    NASA Astrophysics Data System (ADS)

    Kalinichenko, Igor; Kazinski, Peter

    2014-08-01

    The explicit expressions for the one-loop non-perturbative corrections to the gravitational effective action induced by a scalar field on a stationary gravitational background are obtained both at zero and finite temperatures. The perturbative and non-perturbative contributions to the one-loop effective action are explicitly separated. It is proved that, after a suitable renormalization, the perturbative part of the effective action at zero temperature can be expressed in a covariant form solely in terms of the metric and its derivatives. This part coincides with the known large mass expansion of the one-loop effective action. The non-perturbative part of the renormalized one-loop effective action at zero temperature is proved to depend explicitly on the Killing vector defining the vacuum state of quantum fields. This part cannot be expressed in a covariant way through the metric and its derivatives alone. The implications of this result for the structure and symmetries of the effective action for gravity are discussed.

  7. One-loop effective lagrangians after matching

    NASA Astrophysics Data System (ADS)

    del Aguila, F.; Kunszt, Z.; Santiago, J.

    2016-05-01

    We discuss the limitations of the covariant derivative expansion prescription advocated to compute the one-loop Standard Model (SM) effective lagrangian when the heavy fields couple linearly to the SM. In particular, one-loop contributions resulting from the exchange of both heavy and light fields must be explicitly taken into account through matching because the proposed functional approach alone does not account for them. We review a simple case with a heavy scalar singlet of charge -1 to illustrate the argument. As two other examples where this matching is needed and this functional method gives a vanishing result, up to renormalization of the heavy sector parameters, we re-evaluate the one-loop corrections to the T-parameter due to a heavy scalar triplet with vanishing hypercharge coupling to the Brout-Englert-Higgs boson and to a heavy vector-like quark singlet of charged 2 / 3 mixing with the top quark, respectively. In all cases we make use of a new code for matching fundamental and effective theories in models with arbitrary heavy field additions.

  8. Constructing QCD one-loop amplitudes

    SciTech Connect

    Forde, Darren; /SLAC /UCLA

    2008-02-22

    In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behavior of the cut integrand as the unconstrained parameters of a specifically chosen parameterization of the cut loop momentum approach infinity. Measurements of new physics at the forthcoming experimental program at CERN's Large Hadron Collider (LHC) will require a precise understanding of processes at next-to-leading order (NLO). This places increased demands for the computation of new one-loop amplitudes. This in turn has spurred recent developments towards improved calculational techniques. Direct calculations using Feynman diagrams are in general inefficient. Developments of more efficient techniques have usually centered around unitarity techniques [1], where tree amplitudes are effectively 'glued' together to form loops. The most straightforward application of this method, in which the cut loop momentum is in D = 4, allows for the computation of 'cut-constructible' terms only, i.e. (poly)logarithmic containing terms and any related constants. QCD amplitudes contain, in addition to such terms, rational pieces which cannot be derived using such cuts. These 'missing' rational parts can be extracted using cut loop momenta in D = 4-2 {var_epsilon}. The greater difficulty of such calculations has restricted the application of this approach, although recent developments [3, 4] have provided new promise for this technique. Recently the application of on-shell recursion relations [5] to obtaining the 'missing' rational parts of one-loop processes [6] has provided an alternative very promising solution to this problem. In combination with unitarity methods an 'on-shell bootstrap' approach provides an efficient technique for computing complete one-loop QCD amplitudes [7]. Additionally

  9. Pentagon-pentagon correlations in water

    SciTech Connect

    Speedy, R.J.; Mezei, M.

    1985-01-03

    Computer simulation studies on the concentration of pentagonal rings of hydrogen-bonded water molecules (pentagons) and the spatial correlation of pentagons in liquid water are detailed. The pentagon-pentagon correlation function g/sub 55/(r) has a peak at r similarly ordered 3.2 A. The results support the idea that the anomalies of water may be related to the self-replicating propensity of pentagons in the random network. 24 references, 8 figures, 1 table.

  10. Semi-numerical evaluation of one-loop corrections

    SciTech Connect

    Ellis, R.K.; Giele, W.T.; Zanderighi, G.; /Fermilab

    2005-08-01

    We present a semi-numerical algorithm to calculate one-loop virtual corrections to scattering amplitudes. The divergences of the loop amplitudes are regulated using dimensional regularization. We treat in detail the case of amplitudes with up to five external legs and massless internal lines, although the method is more generally applicable. Tensor integrals are reduced to generalized scalar integrals, which in turn are reduced to a set of known basis integrals using recursion relations. The reduction algorithm is modified near exceptional configurations to ensure numerical stability. To test the procedure we apply these techniques to one-loop corrections to the Higgs to four quark process for which analytic results have recently become available.

  11. Direct Extraction of One-loop Integral Coefficients

    SciTech Connect

    Forde, Darren

    2007-04-16

    We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding bubble and triangle integral functions. After choosing a specific parameterization of the cut loop momentum we can uniquely identify the coefficients of the desired integral functions simply by examining the behavior of the cut integrand as the unconstrained parameters of the cut loop momentum approach infinity. In this way we can produce compact forms for scalar integral coefficients. Applications of this method are presented for both QCD and electroweak processes, including an alternative form for the recently computed three-mass triangle coefficient in the six-photon amplitude A{sub 6}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup -}, 6{sup +}). The direct nature of this extraction procedure allows for a very straightforward automation of the procedure.

  12. Reduction of One-Loop Amplitudes at the Integrand Level -- NLO QCD Calculations

    NASA Astrophysics Data System (ADS)

    Ossola, G.; Papadopoulos, C. G.; Pittau, R.

    2008-07-01

    The recently proposed method (OPP) to extract the coefficients of the scalar one-loop integrals to any multi-particle (sub)-amplitude is described. Within this method no analytical information on the structure of the amplitude is needed, allowing for a purely numerical, but still algebraic, implementation of the algorithm. The algorithm can be used to automatically perform one-loop calculation both in QCD and in the EW Theory. As an application, we give QCD one-loop results for the process p p to ZZZ at the LHC.

  13. The universal one-loop effective action

    NASA Astrophysics Data System (ADS)

    Drozd, Aleksandra; Ellis, John; Quevillon, Jérémie; You, Tevong

    2016-03-01

    We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.

  14. One-loop diagrams in AdS space

    SciTech Connect

    Hung Lingyan; Shang Yanwen

    2011-01-15

    We study the complex scalar loop corrections to the boundary-boundary gauge two-point function in pure AdS space in Poincare coordinates, in the presence of boundary quadratic perturbations to the scalar. These perturbations correspond to double-trace perturbations in the dual CFT and modify the boundary conditions of the bulk scalars in AdS. We find that, in addition to the usual UV divergences, the one-loop calculation suffers from a divergence originating in the limit as the loop vertices approach the AdS horizon. We show that this type of divergence is independent of the boundary coupling; making use of this we extract the finite relative variation of the imaginary part of the loop via Cutkosky rules as the boundary perturbation varies. Applying our methods to compute the effects of a time-dependent impurity to the conductivities using the replica trick in AdS/CFT, we find that generally an IR-relevant disorder reduces the conductivity and that in the extreme low frequency limit the correction due to the impurities overwhelms the planar CFT result even though it is supposedly 1/N{sup 2} suppressed. We also comment on the more physical scenario of a time-independent impurity.

  15. One loop superstring effective actions and N=8 supergravity

    SciTech Connect

    Moura, Filipe

    2008-06-15

    In a previous article we have shown the existence of a new independent R{sup 4} term, at one loop, in the type IIA and heterotic effective actions, after reduction to four dimensions, besides the usual square of the Bel-Robinson tensor. It had been shown that such a term could not be directly supersymmetrized, but we showed that was possible after coupling to a scalar chiral multiplet. In this article, we study the extended (N=8) supersymmetrization of this term, where no other coupling can be taken. We show that such supersymmetrization cannot be achieved at the linearized level. This is in conflict with the theory one gets after toroidal compactification of type II superstrings being N=8 supersymmetric. We interpret this result in the face of the recent claim that perturbative supergravity cannot be decoupled from string theory in d{>=}4, and N=8, d=4 supergravity is in the swampland.

  16. Nonorientable one-loop amplitudes for the bosonic open string: Electrostatics on a Moebius strip

    SciTech Connect

    Rodrigues, J.P.

    1987-11-01

    The partition function, N-point scalar, and four-point vector nonorientable one-loop amplitudes for the bosonic open string in the critical dimension are obtained using a first quantized path integral treatment of Polyakov's string that assumes scale independence.

  17. One-loop corrections from higher dimensional tree amplitudes

    NASA Astrophysics Data System (ADS)

    Cachazo, Freddy; He, Song; Yuan, Ellis Ye

    2016-08-01

    We show how one-loop corrections to scattering amplitudes of scalars and gauge bosons can be obtained from tree amplitudes in one higher dimension. Starting with a complete tree-level scattering amplitude of n + 2 particles in five dimensions, one assumes that two of them cannot be "detected" and therefore an integration over their LIPS is carried out. The resulting object, function of the remaining n particles, is taken to be four-dimensional by restricting the corresponding momenta. We perform this procedure in the context of the tree-level CHY formulation of amplitudes. The scattering equations obtained in the procedure coincide with those derived by Geyer et al. from ambitwistor constructions and recently studied by two of the authors for bi-adjoint scalars. They have two sectors of solutions: regular and singular. We prove that the contribution from regular solutions generically gives rise to unphysical poles. However, using a BCFW argument we prove that the unphysical contributions are always homogeneous functions of the loop momentum and can be discarded. We also show that the contribution from singular solutions turns out to be homogeneous as well.

  18. Effective nonrenormalizable theories at one loop

    SciTech Connect

    Gaillard, M.K.

    1987-10-12

    The paper focuses on a nonrenormalizable theory that is more closely related to those suggested by superstrings, namely a gauged nonlinear delta-model, but one which can also be obtained analytically in a particular limit of a parameter (m/sub H/ ..-->.. infinity) of the standard, renormalizable electroweak theory. This will provide another laboratory for testing the validity of calculations using the effective theory. We find (as for certain superstring inspired models to be discussed later) features similar to those for the Fermi theory: quadratic divergences can be reinterpreted as renormalizations, while new terms are generated at the level of logarithmic divergences. Also introduced in the context of more familiar physics are notions such as scalar metric, scalar curvature and nonlinear symmetries, that play an important role in formal aspects of string theories. 58 refs., 12 figs.

  19. One-loop graviton corrections to the curvature perturbation from inflation

    SciTech Connect

    Dimastrogiovanni, Emanuela; Bartolo, Nicola E-mail: nicola.bartolo@pd.infn.it

    2008-11-15

    We compute one-loop corrections to the power spectrum of the curvature perturbation in single-field slow-roll inflation arising from gravitons and inflaton interactions. The quantum corrections due to gravitons to the power spectrum of the inflaton field are computed around the time of horizon crossing and their effect on the curvature perturbation is obtained on superhorizon scales through the {delta}N formalism. We point out that one-loop corrections from the tensor modes are of the same magnitude as those coming from scalar self-interactions; therefore they cannot be neglected in a self-consistent calculation.

  20. The rational parts of one-loop QCD amplitudes III: The six-gluon case

    NASA Astrophysics Data System (ADS)

    Xiao, Zhi-Guang; Yang, Gang; Zhu, Chuan-Jie

    2006-12-01

    The rational parts of 6-gluon one-loop amplitudes with scalars circulating in the loop are computed by using the newly developed method for computing the rational parts directly from Feynman integrals. We present the analytic results for the two MHV helicity configurations: (123456) and (123456), and the two NMHV helicity configurations: (123456) and (123456). Combined with the previously computed results for the cut-constructible part, our results are the last missing pieces for the complete partial helicity amplitudes of the 6-gluon one-loop QCD amplitude.

  1. Third generation sfermion decays into Z and W gauge bosons: Full one-loop analysis

    SciTech Connect

    Arhrib, Abdesslam; Benbrik, Rachid

    2005-05-01

    The complete one-loop radiative corrections to third-generation scalar fermions into gauge bosons Z and W{sup {+-}} is considered. We focus on f-tilde{sub 2}{yields}Zf-tilde{sub 1} and f-tilde{sub i}{yields}W{sup {+-}}f-tilde{sub j}{sup '}, f,f{sup '}=t,b. We include SUSY-QCD, QED, and full electroweak corrections. It is found that the electroweak corrections can be of the same order as the SUSY-QCD corrections. The two sets of corrections interfere destructively in some region of parameter space. The full one-loop correction can reach 10% in some supergravity scenario, while in model independent analysis like general the minimal supersymmetric standard model, the one-loop correction can reach 20% for large tan{beta} and large trilinear soft breaking terms A{sub b}.

  2. One-loop gravitational wave spectrum in de Sitter spacetime

    SciTech Connect

    Fröb, Markus B.; Verdaguer, Enric

    2012-08-01

    The two-point function for tensor metric perturbations around de Sitter spacetime including one-loop corrections from massless conformally coupled scalar fields is calculated exactly. We work in the Poincare patch (with spatially flat sections) and employ dimensional regularization for the renormalization process. Unlike previous studies we obtain the result for arbitrary time separations rather than just equal times. Moreover, in contrast to existing results for tensor perturbations, ours is manifestly invariant with respect to the subgroup of de Sitter isometries corresponding to a simultaneous time translation and rescaling of the spatial coordinates. Having selected the right initial state for the interacting theory via an appropriate iε prescription is crucial for that. Finally, we show that although the two-point function is a well-defined spacetime distribution, the equal-time limit of its spatial Fourier transform is divergent. Therefore, contrary to the well-defined distribution for arbitrary time separations, the power spectrum is strictly speaking ill-defined when loop corrections are included.

  3. PV at the Pentagon

    SciTech Connect

    Bing, J.

    2000-02-01

    The US Department of Defense joins the battle against global warming with a photovoltaic installation at the Pentagon heating and refrigeration plant. Sitting in a line between the Pentagon and the Oval Office are four concentric arcs of iridescent silicon. In June 1999, the first half of this thirty kilowatt photovoltaic (PV) system was dedicated on the grounds of the heating and refrigeration plant that serves the Pentagon near Washington, DC. This first half of the system (the two center arcs) is the world's largest array composed solely of Ascension Technology's SunSine{reg{underscore}sign}300 AC modules. Each of these photovoltaic panels has its own DC to AC inverter mounted directly on its back side. The second half of the installation, brought on line in October 1999, includes a conventional DC array that powers a pair of newly developed Trace Technologies 10 kW inverters. The AC output of these two unique PV systems is combined at a central collection point and funneled into the electric grid that supplies power to the Pentagon. The project is a collaboration of the US Department of Defense (DoD) and the US Department of Energy (DOE), with cost-sharing support from Virginia Power, Johnson Controls, the Utility Photovoltaic Group (UPVG), and Applied Power Corporation. The systems were designed and installed by Ascension Technology, a division of Applied Power Corporation, with modules supplied by ASE Americas. This installation provides a unique real-world environment for researchers, utility engineers and power plant managers to test and compare the reliability, scalability, noise immunity and power quality of these two distinct approaches to PV energy production.

  4. A Mathematica package for calculation of one-loop penguins in FCNC processes

    NASA Astrophysics Data System (ADS)

    Bednyakov, Alexander Vadimovich; Tanyıldızı, Şükrü Hanif

    2015-09-01

    In this work, we present a Mathematica package Peng4BSM@LO which calculates the contributions to the Wilson Coefficients of certain effective operators originating from the one-loop penguin Feynman diagrams. Both vector and scalar external legs are considered. The key feature of our package is the ability to find the corresponding expressions in almost any New Physics model which extends the SM and has no flavor changing neutral current (FCNC) transitions at the tree level.

  5. Full one-loop amplitudes from tree amplitudes

    SciTech Connect

    Giele, Walter T.; Kunszt, Zoltan; Melnikov, Kirill; /Hawaii U.

    2008-01-01

    We establish an efficient polynomial-complexity algorithm for one-loop calculations, based on generalized D-dimensional unitarity. It allows automated computations of both cut-constructible and rational parts of one-loop scattering amplitudes from on-shell tree amplitudes. We illustrate the method by (re)-computing all four-, five- and six-gluon scattering amplitudes in QCD at one-loop.

  6. Complete algebraic reduction of one-loop tensor Feynman integrals

    SciTech Connect

    Fleischer, J.; Riemann, T.

    2011-04-01

    We set up a new, flexible approach for the tensor reduction of one-loop Feynman integrals. The 5-point tensor integrals up to rank R=5 are expressed by 4-point tensor integrals of rank R-1, such that the appearance of the inverse 5-point Gram determinant is avoided. The 4-point tensor coefficients are represented in terms of 4-point integrals, defined in d dimensions, 4-2{epsilon}{<=}d{<=}4-2{epsilon}+2(R-1), with higher powers of the propagators. They can be further reduced to expressions which stay free of the inverse 4-point Gram determinants but contain higher-dimensional 4-point integrals with only the first power of scalar propagators, plus 3-point tensor coefficients. A direct evaluation of the higher-dimensional 4-point functions would avoid the appearance of inverse powers of the Gram determinants completely. The simplest approach, however, is to apply here dimensional recurrence relations in order to reduce them to the familiar 2- to 4-point functions in generic dimension d=4-2{epsilon}, introducing thereby coefficients with inverse 4-point Gram determinants up to power R for tensors of rank R. For small or vanishing Gram determinants--where this reduction is not applicable--we use analytic expansions in positive powers of the Gram determinants. Improving the convergence of the expansions substantially with Pade approximants we close up to the evaluation of the 4-point tensor coefficients for larger Gram determinants. Finally, some relations are discussed which may be useful for analytic simplifications of Feynman diagrams.

  7. A critical analysis of one-loop neutrino mass models with minimal dark matter

    NASA Astrophysics Data System (ADS)

    Ahriche, Amine; McDonald, Kristian L.; Nasri, Salah; Picek, Ivica

    2016-06-01

    A recent paper investigated minimal RνMDM models with the type T1-iii and T3 one-loop topologies. However, the candidate most-minimal model does not possess an accidental symmetry - the scalar potential contains an explicit symmetry breaking term, rendering the dark matter unstable. We present two models that cure this problem. However, we further show that all of the proposed minimal one-loop RνMDM models suffer from a second problem - an additional source of explicit Z2 symmetry breaking in the Yukawa sector. We perform a more-general analysis to show that neutrino mass models using either the type T3 or type T1-iii one-loop topologies do not give viable minimal dark matter candidates. Consequently, one-loop models of neutrino mass with minimal dark matter do not appear possible. Thus, presently there remains a single known (three-loop) model of neutrino mass that gives stable dark matter without invoking any new symmetries.

  8. One-loop soft supersymmetry breaking terms in superstring effective theories.

    SciTech Connect

    Binetruy, Pierre; Gaillard, Mary K.; Nelson, Brent D.

    2000-11-01

    We perform a systematic analysis of soft supersymmetry breaking terms at the one loop level in a large class of string effective field theories. This includes the so-called anomaly mediated contributions. We illustrate our results for several classes of orbifold models. In particular, we discuss a class of models where soft supersymmetry breaking terms are determined by quasi model independent anomaly mediated contributions, with possibly non-vanishing scalar masses at the one loop level. We show that the latter contribution depends on the detailed prescription of the regularization process which is assumed to represent the Planck scale physics of the underlying fundamental theory. The usual anomaly mediation case with vanishing scalar masses at one loop is not found to be generic. However gaugino masses and A-terms always vanish at tree level if supersymmetry breaking is moduli dominated with the moduli stabilized at self-dual points, whereas the manishing of the B-term depends on the origin of the mu-term in the underlying theory. We also discuss the supersymmetric spectrum of O-I and O-II models, as well as a model of gaugino condensation. For reference, explicit spectra corresponding to a Higgs mass of 114 GeV are given. Finally, we address general strategies for distinguishing among these models.

  9. One loop partition function of three-dimensional flat gravity

    NASA Astrophysics Data System (ADS)

    Barnich, G.; González, H. A.; Maloney, A.; Oblak, B.

    2015-04-01

    In this note we point out that the one-loop partition function of threedimensional flat gravity, computed along the lines originally developed for the anti-de Sitter case, reproduces characters of the BMS3 group.

  10. New Method for One-Loop Scattering Amplitudes in Field Theory

    SciTech Connect

    Ossola, Giovanni

    2009-12-17

    We review the main features of the OPP method for the evaluation of one-loop amplitudes of arbitrary scattering processes. In this approach, the coefficients of the scalar integrals are extracted by means of simple algebraic equations constructed by numerically evaluating the numerator of the integrand for specific choices of the integration momentum. No analytical information on the structure of the amplitude is needed, allowing for a purely numerical, but still algebraic, implementation of the algorithm. The method works for any set of internal and/or external masses, without being limited to massless theories.

  11. One-loop amplitudes on the Riemann sphere

    NASA Astrophysics Data System (ADS)

    Geyer, Yvonne; Mason, Lionel; Monteiro, Ricardo; Tourkine, Piotr

    2016-03-01

    The scattering equations provide a powerful framework for the study of scattering amplitudes in a variety of theories. Their derivation from ambitwistor string theory led to proposals for formulae at one loop on a torus for 10 dimensional supergravity, and we recently showed how these can be reduced to the Riemann sphere and checked in simple cases. We also proposed analogous formulae for other theories including maximal super-Yang-Mills theory and supergravity in other dimensions at one loop. We give further details of these results and extend them in two directions. Firstly, we propose new formulae for the one-loop integrands of Yang-Mills theory and gravity in the absence of supersymmetry. These follow from the identification of the states running in the loop as expressed in the ambitwistor-string correlator. Secondly, we give a systematic proof of the non-supersymmetric formulae using the worldsheet factorisation properties of the nodal Riemann sphere underlying the scattering equations at one loop. Our formulae have the same decomposition under the recently introduced Q-cuts as one-loop integrands and hence give the correct amplitudes.

  12. Superstring one-loop and gravitino contributions to planckian scattering

    NASA Astrophysics Data System (ADS)

    Bellini, Alessandro; Ademollo, Marco; Ciafaloni, Marcello

    1993-03-01

    Corrections to the semiclassical approximation in nearly forward planckian energy collisions are reconsidered. Starting from the one-loop superstring amplitude, we are able to disentangle the first subleading high-energy contribution at large impact parameters, and we thus directly compute the one-loop correction to the superstring eikonal. By comparing this result with previous ones by Amati, Ciafaloni and Veneziano (ACV) for pure gravity, we identify one-loop gravitino contributions which agree with previous results by Lipatov. We finally argue, on the basis of analyticity and unitarity, that gravitinos do not contribute at all the large-distance two-loop ACV correction, which thus acquires a universal "classical" interpretation.

  13. All one-loop NMHV gluon amplitudes in = 1 SYM

    NASA Astrophysics Data System (ADS)

    Ochirov, Alexander

    2013-12-01

    We compute the next-to-maximally-helicity-violating one-loop n-gluon amplitudes in = 1 super-Yang-Mills theory. These amplitudes contain three negative-helicity gluons and an arbitrary number of positive-helicity gluons, and constitute the first infinite series of amplitudes beyond the simplest, MHV, amplitudes. We assemble ingredients from the = 4 NMHV tree super-amplitude into previously unwritten double cuts and use the spinor integration technique to calculate all bubble coefficients. We also derive the missing box coefficients from quadruple cuts. Together with the known formula for three-mass triangles, this completes the set of NMHV one-loop master integral coefficients in = 1 SYM. To facilitate further use of our results, we provide their Mathematica implementation.

  14. N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop

    SciTech Connect

    Bern, Z.; Boucher-Veronneau, C.; Johansson, H.; /Saclay

    2011-08-19

    We expose simple and practical relations between the integrated four- and five-point one-loop amplitudes of N {ge} 4 supergravity and the corresponding (super-)Yang-Mills amplitudes. The link between the amplitudes is simply understood using the recently uncovered duality between color and kinematics that leads to a double-copy structure for gravity. These examples provide additional direct confirmations of the duality and double-copy properties at loop level for a sample of different theories.

  15. Symbols of one-loop integrals from mixed Tate motives

    NASA Astrophysics Data System (ADS)

    Spradlin, Marcus; Volovich, Anastasia

    2011-11-01

    We use a result on mixed Tate motives due to Goncharov [1] to show that the symbol of an arbitrary one-loop 2 m-gon integral in 2 m dimensions may be read off directly from its Feynman parameterization. The algorithm proceeds via recursion in m seeded by the well-known box integrals in four dimensions. As a simple application of this method we write down the symbol of a three-mass hexagon integral in six dimensions.

  16. One-loop effective potential of the Higgs field on the Schwarzschild background

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.

    2009-12-01

    A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. It is shown that the obtained potential is generally covariant, depends on the space point through the metric component g00 in the adapted coordinates, and has the same form for an arbitrary static, spherically symmetric background. Some properties of this potential are investigated. In particular, if the conformal symmetry holds valid for massless particles on the given background, there exist only two possible scenarios depending on the sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely, when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. If the conformal symmetry is spoiled, an additional term in the effective potential appears and the intermediate regime arises. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases. It should be mentioned that the use of the one-loop approximation becomes questionable in the region where the one-loop effective potential acquires large values. So, in that region, we can believe in the obtained results only to a certain extent.

  17. Closed-form decomposition of one-loop massive amplitudes

    SciTech Connect

    Britto, Ruth; Feng Bo; Mastrolia, Pierpaolo

    2008-07-15

    We present formulas for the coefficients of 2-, 3-, 4-, and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions, after simple algebraic manipulations. The formulas presented here are suitable for analytical as well as numerical evaluation. Their validity is confirmed in two known cases of helicity amplitudes contributing to gg{yields}gg and gg{yields}gH, where the masses of the Higgs and the fermion circulating in the loop are kept as free parameters.

  18. The one loop corrections to the neutrino masses in BLMSSM

    NASA Astrophysics Data System (ADS)

    Zhao, Shu-Min; Feng, Tai-Fu; Dong, Xing-Xing; Zhang, Hai-Bin; Ning, Guo-Zhu; Guo, Tao

    2016-09-01

    The neutrino masses and mixings are studied in the model which is the supersymmetric extension of the standard model with local gauged baryon and lepton numbers (BLMSSM). At tree level the neutrinos can obtain tiny masses through the See-Saw mechanism in the BLMSSM. The one-loop corrections to the neutrino masses and mixings are important, and they are studied in this work with the mass insertion approximation. We study the numerical results and discuss the allowed parameter space of BLMSSM. It can contribute to study the neutrino masses and to explore the new physics beyond the standard model (SM).

  19. Two loop divergences studied with one loop constrained differential renormalization

    SciTech Connect

    Seijas, Cesar . E-mail: cesar@fpaxp1.usc.es

    2007-08-15

    In the context of differential renormalization, using constrained differential renormalization rules at one-loop, we show how to obtain concrete results in two-loop calculations without making use of Ward identities. In order to do that, we obtain a list of integrals with overlapping divergences compatible with CDR that can be applied to various two-loop background field calculations. As an example, we obtain the two-loop coefficient of the beta function of QED, SuperQED and Yang-Mills theory.

  20. Elliptic multiple zeta values and one-loop superstring amplitudes

    NASA Astrophysics Data System (ADS)

    Broedel, Johannes; Mafra, Carlos R.; Matthes, Nils; Schlotterer, Oliver

    2015-07-01

    We investigate iterated integrals on an elliptic curve, which are a natural genus-one generalization of multiple polylogarithms. These iterated integrals coincide with the multiple elliptic polylogarithms introduced by Brown and Levin when constrained to the real line. At unit argument they reduce to an elliptic analogue of multiple zeta values, whose network of relations we start to explore. A simple and natural application of this framework are one-loop scattering amplitudes in open superstring theory. In particular, elliptic multiple zeta values are a suitable language to express their low energy limit. Similar to the techniques available at tree-level, our formalism allows to completely automatize the calculation.

  1. An explanation of one-loop induced h → μτ decay

    NASA Astrophysics Data System (ADS)

    Baek, Seungwon; Nomura, Takaaki; Okada, Hiroshi

    2016-08-01

    We discuss a possibility to explain the excess of h → μτ at one-loop level. We introduce three generations of vector-like lepton doublet L‧ and two singlet scalars S1,2 which are odd under Z2, while all the standard model fields are even under this discrete symmetry. We show that S1 can be a good dark matter candidate. We show that we can explain the dark matter relic abundance, large part of the discrepancy of muon g - 2 between experiments and the standard model predictions, as well as the h → μτ excess of ∼ 1%, while evading constraints from experiments of dark matter direct detection and charged lepton flavor violating processes. We also consider prospects of production of S2 at LHC with energy √{ s} = 14 TeV.

  2. A simple method for one-loop renormalization in curved space-time

    SciTech Connect

    Markkanen, Tommi; Tranberg, Anders E-mail: anders.tranberg@uis.no

    2013-08-01

    We present a simple method for deriving the renormalization counterterms from the components of the energy-momentum tensor in curved space-time. This method allows control over the finite parts of the counterterms and provides explicit expressions for each term separately. As an example, the method is used for the self-interacting scalar field in a Friedmann-Robertson-Walker metric in the adiabatic approximation, where we calculate the renormalized equation of motion for the field and the renormalized components of the energy-momentum tensor to fourth adiabatic order while including interactions to one-loop order. Within this formalism the trace anomaly, including contributions from interactions, is shown to have a simple derivation. We compare our results to those obtained by two standard methods, finding agreement with the Schwinger-DeWitt expansion but disagreement with adiabatic subtractions for interacting theories.

  3. Pentagon getting first energy audit

    SciTech Connect

    Betts, M.

    1982-03-29

    The General Services Administration is conducting the first comprehensive energy audit of the Pentagon, the world's largest office building, after criticism from the General Accounting Office over the delay. The auditors will identify both low-cost options with quick returns and opportunities for major retrofit projects. The building design is not energy-efficient, and had the second highest use of Btus per gross square foot of area buildings in 1981. (DCK)

  4. A Pentagon Based Carbon Sheet

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Zhang, Shunhong; Zhou, Jian; Chen, Xiaoshuang; Kawazoe, Yoshiyuki; Jena, Puru; A international Team Collaboration

    2015-03-01

    A new two-dimensional (2D) meta-stable carbon allotrope, penta-graphene, composed entirely of carbon pentagons and resembling the Cairo pentagonal tiling, is proposed. State-of-the-art theoretical calculations confirm that the new carbon polymorph is not only dynamically and mechanically stable, but also can withstand temperatures as high as 1000 K. Due to its unique atomic configuration penta-graphene has an unusual negative Poisson's ratio (NPR) and ultra-high ideal strength that can even outperform graphene. Furthermore, unlike graphene that needs to be functionalized for opening a band gap, penta-graphene possesses an intrinsic quasi-direct band gap as large as 3.25 eV - close to that of ZnO and GaN. Equally important, when rolled up, penta-graphene can form a pentagon-based nanotube. The resulting penta-carbon nanotubes are semiconducting regardless of their chirality. When stacked in different patterns, dynamically and thermally stable 3D twin structures of T12-carbon are generated with band gaps even larger than that of T12-carbon. The versatility of penta-graphene and its derivatives are expected to have broad applications in nanoelectronics and nanomechanics. Peking University.

  5. Bootstrapping One-Loop QCD Amplitudeswith General Helicities

    SciTech Connect

    Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren; Kosower, David A.

    2006-04-25

    The recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD combines the unitarity method with loop-level on-shell recursion. For generic helicity configurations, the recursion relations may involve undetermined contributions from non-standard complex singularities or from large values of the shift parameter. Here we develop a strategy for sidestepping difficulties through use of pairs of recursion relations. To illustrate the strategy, we present sets of recursion relations needed for obtaining n-gluon amplitudes in QCD. We give a recursive solution for the one-loop n-gluon QCD amplitudes with three or four color-adjacent gluons of negative helicity and the remaining ones of positive helicity. We provide an explicit analytic formula for the QCD amplitude A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}), as well as numerical results for A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}), and A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup -}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}). We expect the on-shell bootstrap approach to have widespread applications to phenomenological studies at colliders.

  6. Dirac dark matter with a charged mediator: a comprehensive one-loop analysis of the direct detection phenomenology

    SciTech Connect

    Ibarra, Alejandro; Wild, Sebastian E-mail: sebastian.wild@ph.tum.de

    2015-05-01

    We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess.

  7. Dirac dark matter with a charged mediator: a comprehensive one-loop analysis of the direct detection phenomenology

    SciTech Connect

    Ibarra, Alejandro; Wild, Sebastian

    2015-05-26

    We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess.

  8. One-Loop Calculations with BlackHat

    SciTech Connect

    Berger, C.F.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Forde, D.; Ita, H.; Kosower, D.A.; Maitre, D.

    2008-08-01

    We describe BlackHat, an automated C++ program for calculating one-loop amplitudes, and the techniques used in its construction. These include the unitarity method and on-shell recursion. The other ingredients are compact analytic formulae for tree amplitudes for four-dimensional helicity states. The program computes amplitudes numerically, using analytic formula only for the tree amplitudes, the starting point for the recursion, and the loop integrals. We make use of recently developed on-shell methods for evaluating coefficients of loop integrals, in particular a discrete Fourier projection as a means of improving numerical stability. We illustrate the good numerical stability of this approach by computing six-, seven- and eight-gluon amplitudes in QCD and comparing against known analytic results.

  9. One-loop quantum gravity repulsion in the early Universe.

    PubMed

    Broda, Bogusław

    2011-03-11

    Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.

  10. Regioselective Oxidation of Fused-Pentagon Chlorofullerenes.

    PubMed

    Zhang, Zhen-Qiang; Chen, Shu-Fen; Gao, Cong-Li; Zhou, Ting; Shan, Gui-Juan; Tan, Yuan-Zhi; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2016-01-19

    Two monoxides of typical smaller chlorofullerenes, (#271)C50Cl10O and (#913)C56Cl10O, featured with double-fused-pentagons, were synthesized to demonstrate further regioselective functionalization of non-IPR (IPR = isolated pentagon rule) chlorofullerenes. Both non-IPR chlorofullerene oxides exhibit an epoxy structure at the ortho-site of fused pentagons. In terms of the geometrical analysis and theoretical calculations, the principles for regioselective epoxy oxidation of non-IPR chlorofullerenes are revealed to follow both "fused-pentagon ortho-site" and "olefinic bond" rules, which are valuable for prediction of oxidation of non-IPR chlorofullerenes. PMID:26726707

  11. Pentagon After Action Reports: The Jack Taylor Debate.

    ERIC Educational Resources Information Center

    Abbott, Stan

    In requesting after action reports--Pentagon-prepared summaries of interviews between reporters and Pentagon officials--investigative reporter Jack Taylor both aroused Pentagon opposition and created a rift between the Pentagon press corps and outside reporters. To investigate whether the full-time Pentagon press corps was reporting as…

  12. 14. Detail of possible entrance on north side of Pentagon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Detail of possible entrance on north side of Pentagon 2 (note leaning logs at center). View to west. - Pentagon Site, Pentagon 2, West of Barry's Landing off Highway 37, Fort Smith, Big Horn County, MT

  13. 15. Detail of log cribbing on southeast side of Pentagon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Detail of log cribbing on southeast side of Pentagon 1 (note stone in center). View to northwest. - Pentagon Site, Pentagon 1, West of Barry's Landing off Highway 37, Fort Smith, Big Horn County, MT

  14. 1. Overall view of Pentagon 2 (in center of photo), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Overall view of Pentagon 2 (in center of photo), with Bad Pass Trail in background. View to southeast. - Pentagon Site, Pentagon 2, West of Barry's Landing off Highway 37, Fort Smith, Big Horn County, MT

  15. 11. Detail of log cribbing on north side of Pentagon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Detail of log cribbing on north side of Pentagon 1, (note stone in left foreground). View to south. - Pentagon Site, Pentagon 1, West of Barry's Landing off Highway 37, Fort Smith, Big Horn County, MT

  16. One-loop quantum gravity in the Einstein universe

    NASA Astrophysics Data System (ADS)

    Avramidi, Ivan G.; Collopy, Samuel J.

    2015-11-01

    We study quantum gravity with the Einstein-Hilbert action including the cosmological constant on the Euclidean Einstein universe S 1 × S 3. We compute exactly the spectra and the heat kernels of the relevant operators on S 3 and use these results to compute the heat trace of the graviton and ghost operators and the exact one-loop effective action on S 1 × S 3. We show that the system is unstable in the infrared limit due to the presence of the negative modes of the graviton and the ghost operators. We study the thermal properties of the model with the temperature T = (2 πa 1)-1 determined by the radius a 1 of the circle S 1. We show that the heat capacity C v is well defined and behaves like ˜ T 3 in the high temperature limit and has a singularity of the type ˜ ( T - T c )-1, indicating a second-order phase transition, with the critical temperature T c determined by the cosmological constant Λ and the radius a of the sphere S 3. We also discuss some peculiar properties of the model such as the negative heat capacity as well as possible physical applications.

  17. Electroweak precision observables at one loop in Higgsless models

    SciTech Connect

    Cata, Oscar; Kamenik, Jernej F.

    2011-03-01

    We study the viability of generic Higgsless models at low energies when compliance with electroweak precision observables and unitarity constraints up to the TeV scale are imposed. Our analysis shows that consistency with S and T can be achieved at the one-loop level even with a single light vector state, m{sub V} < or approx. 500 GeV. However, this scenario turns out to be strongly disfavored when direct resonance searches at the Tevatron are also taken into account. We show that a fully consistent picture can be obtained if an axial state is introduced. Interestingly, m{sub V} is still predicted to be light (below 1 TeV) while typical values of m{sub A} span over the window 1.2m{sub V}{<=}m{sub A}{<=}1.4m{sub V}. Our results for the vector channel are rather robust and well within the reach of present-day colliders, while the axial channel is more loosely constrained.

  18. Regular Pentagons and the Fibonacci Sequence.

    ERIC Educational Resources Information Center

    French, Doug

    1989-01-01

    Illustrates how to draw a regular pentagon. Shows the sequence of a succession of regular pentagons formed by extending the sides. Calculates the general formula of the Lucas and Fibonacci sequences. Presents a regular icosahedron as an example of the golden ratio. (YP)

  19. Pentagon chain in external fields

    NASA Astrophysics Data System (ADS)

    Kovács, György; Gulácsi, Zsolt

    2015-11-01

    We consider a pentagon chain described by a Hubbard type of model considered under periodic boundary conditions. The system (i) is placed in an external magnetic field perpendicular to the plane of the cells, and (ii) is in a site-selective manner under the action of an external electric potential. In these conditions, we show in an exact manner that the physical properties of the system can be qualitatively changed. The changes cause first strong modifications of the band structure of the system created by the one-particle part of the Hamiltonian, and second, produce marked changes of the phase diagram. We exemplify this by deducing ferromagnetic ground states in the presence of external fields in two different domains of the parameter space.

  20. Analytic one-loop amplitudes for a Higgs boson plus four partons

    SciTech Connect

    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.

  1. Automated One-loop Computation in Quarkonium Process within NRQCD Framework

    NASA Astrophysics Data System (ADS)

    Feng, Feng

    2014-06-01

    In last decades, it has been realized that the next-to-leading order corrections may become very important, and sometimes requisite, for some processes involving quarkoinum production or decay, e.g., e+e- → J/ψ + ηc and J/ψ → 3γ. In this article, we review some basic steps to perform automated one-loop computations in quarkonium process within the Non-relativistic Quantum Chromodynamics (NRQCD) factorization framework1 and we give an introduction to some related public tools or packages and their usages in each step. We start from generating Feynman diagrams and amplitudes with FEYNARTS for the quarkonium process, performing Dirac- and Color- algebras simplifications using FEYNCALC and FEYNCALCFORMLINK, and then to doing partial fractions on the linear-dependent propagators by APART, and finally to reducing the Tensor Integrals (TI) into Scalar Integrals (SI) or Master Integrals (MI) using Integration-By-Parts (IBP) method with the help of FIRE. We will use a simple concrete example to demonstrate the basic usages of the corresponding packages or tools in each step.

  2. Activities: Golden Triangles, Pentagons, and Pentagrams.

    ERIC Educational Resources Information Center

    Miller, William A.; Clason, Robert G.

    1994-01-01

    Presents lesson plans for activities to introduce recursive sequences of polygons: golden triangles, regular pentagons, and pentagrams. The resulting number patterns involve Fibonacci sequences. Includes reproducible student worksheets. (MKR)

  3. The Pentagon Problem: Geometric Reasoning with Technology.

    ERIC Educational Resources Information Center

    Zbiek, Rose Mary

    1996-01-01

    Presents an activity, involving pentagons and using a figure manipulator such as The Geometer's Sketchpad, that requires students to reason geometrically without making unsubstantiated assumptions based on diagrams. (MKR)

  4. Bern-Carrasco-Johansson relations for one-loop QCD integral coefficients

    NASA Astrophysics Data System (ADS)

    Chester, David

    2016-03-01

    We present a set of one-loop integral coefficient relations in QCD. The unitarity method is useful for exposing one-loop amplitudes in terms of tree amplitudes. The coefficient relations are induced by tree-level Bern-Carrasco-Johansson amplitude relations. We provide examples for box, triangle, and bubble coefficients. These relations reduce the total number of independent coefficients needed to calculate one-loop QCD amplitudes.

  5. Experimental Realization of a Quantum Pentagonal Lattice

    PubMed Central

    Yamaguchi, Hironori; Okubo, Tsuyoshi; Kittaka, Shunichiro; Sakakibara, Toshiro; Araki, Koji; Iwase, Kenji; Amaya, Naoki; Ono, Toshio; Hosokoshi, Yuko

    2015-01-01

    Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL. PMID:26468930

  6. Experimental Realization of a Quantum Pentagonal Lattice.

    PubMed

    Yamaguchi, Hironori; Okubo, Tsuyoshi; Kittaka, Shunichiro; Sakakibara, Toshiro; Araki, Koji; Iwase, Kenji; Amaya, Naoki; Ono, Toshio; Hosokoshi, Yuko

    2015-01-01

    Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL. PMID:26468930

  7. Experimental Realization of a Quantum Pentagonal Lattice

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hironori; Okubo, Tsuyoshi; Kittaka, Shunichiro; Sakakibara, Toshiro; Araki, Koji; Iwase, Kenji; Amaya, Naoki; Ono, Toshio; Hosokoshi, Yuko

    2015-10-01

    Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL.

  8. The corrections from one loop and two-loop Barr-Zee type diagrams to muon MDM in BLMSSM

    NASA Astrophysics Data System (ADS)

    Zhao, Shu-Min; Feng, Tai-Fu; Zhang, Hai-Bin; Yan, Ben; Zhan, Xi-Jie

    2014-11-01

    In a supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries(BLMSSM) and the Yukawa couplings between Higgs doublets and exotic quarks are considered, we study the one loop diagrams and the two-loop Barr-Zee type diagrams with a closed Fermi(scalar) loop between the vector Boson and Higgs. Using the effective Lagrangian method, we deduce the Wilson coefficients of dimension 6 operators contributing to the anomalous magnetic moment of muon, which satisfies the electromagnetic gauge invariance. In the numerical analysis, we consider the experiment constraints from Higgs and neutrino data. In some parameter space, the new physics contribution is large and even reaches 24 × 10-10, which can remedy the deviation well.

  9. The One-Loop Six-Dimensional Hexagon Integral and its Relation to MHV Amplitudes in N=4 SYM

    SciTech Connect

    Dixon, Lance J.; Drummond, James M.; Henn, Johannes M.; /Humboldt U., Berlin

    2011-08-19

    We provide an analytic formula for the (rescaled) one-loop scalar hexagon integral {tilde {Phi}}{sub 6} with all external legs massless, in terms of classical polylogarithms. We show that this integral is closely connected to two integrals appearing in one- and two-loop amplitudes in planar N = 4 super-Yang-Mills theory, {Omega}{sup (1)} and {Omega}{sup (2)}. The derivative of {Omega}{sup (2)} with respect to one of the conformal invariants yields {tilde {Phi}}{sub 6}, while another first-order differential operator applied to {tilde {Phi}}{sub 6} yields {Omega}{sup (1)}. We also introduce some kinematic variables that rationalize the arguments of the polylogarithms, making it easy to verify the latter differential equation. We also give a further example of a six-dimensional integral relevant for amplitudes in N = 4 super-Yang-Mills.

  10. Hexagonal and Pentagonal Fractal Multiband Antennas

    NASA Technical Reports Server (NTRS)

    Tang, Philip W.; Wahid, Parveen

    2005-01-01

    Multiband dipole antennas based on hexagonal and pentagonal fractals have been analyzed by computational simulations and functionally demonstrated in experiments on prototypes. These antennas are capable of multiband or wide-band operation because they are subdivided into progressively smaller substructures that resonate at progressively higher frequencies by virtue of their smaller dimensions. The novelty of the present antennas lies in their specific hexagonal and pentagonal fractal configurations and the resonant frequencies associated with them. These antennas are potentially applicable to a variety of multiband and wide-band commercial wireless-communication products operating at different frequencies, including personal digital assistants, cellular telephones, pagers, satellite radios, Global Positioning System receivers, and products that combine two or more of the aforementioned functions. Perhaps the best-known prior multiband antenna based on fractal geometry is the Sierpinski triangle antenna (also known as the Sierpinski gasket), shown in the top part of the figure. In this antenna, the scale length at each iteration of the fractal is half the scale length of the preceding iteration, yielding successive resonant frequencies related by a ratio of about 2. The middle and bottom parts of the figure depict the first three iterations of the hexagonal and pentagonal fractals along with typical dipole-antenna configuration based on the second iteration. Successive resonant frequencies of the hexagonal fractal antenna have been found to be related by a ratio of about 3, and those of the pentagonal fractal antenna by a ratio of about 2.59.

  11. Pentagon Seeks to Build Bridges to Academe.

    ERIC Educational Resources Information Center

    Norman, Colin

    1985-01-01

    The Department of Defense is increasing funding for high-risk basic research, research fellowships, multidisciplinary centers, and purchase of research equipment at universities. Disputes on publishing unclassified data remain, but the Pentagon supports broad university programs and the education of scientists and engineers to meet defense and…

  12. A New Angle for Constructing Pentagons.

    ERIC Educational Resources Information Center

    Benson, John; Borkovitz, Debra

    1982-01-01

    The construction of a pentagon is divided into three problems, designed to enhance the traditional high school geometry class. The material is seen to serve as a potential springboard for many other activities. It is felt most students could not realistically be expected to solve the third problem by themselves. (MP)

  13. The ILS--The Pentagon Library's Experience.

    ERIC Educational Resources Information Center

    Mullane, Ruth

    1984-01-01

    Describes implementation of five subsystems of Integrated Library System's (ILS) version 2.1 (minicomputer-based automated library system) at the Pentagon Library: online catalog (search strategies, user acceptance); bibliographic subsystems (cataloging, retrospective conversion); circulation; serials check-in; administrative subsystem (report…

  14. Coannihilation with a chargino and gauge boson pair production at one-loop

    SciTech Connect

    Baro, N.; Chalons, G.; Hao, Sun

    2010-02-10

    We present a complete calculation of the electroweak one-loop corrections to the relic density within the MSSM framework. In the context of the neutralino as dark matter candidate, we review different scenarios of annihilation and coannihilation with a chargino. In particular we investigate predictions for the annihilation into gauge boson pairs for different kinds of neutralino: bino-, wino- and higgsino-like. We present some interesting effects which are not present at tree-level and show up at one-loop. To deal with the large number of diagrams occurring in the calculations, we have developed an automatic tool for the computation at one-loop of any process in the MSSM. We have implemented a complete on-shell gauge invariant renormalization scheme, with the possibility of switching to other schemes. We emphasize the variations due to the choice of the renormalization scheme, in particular the one-loop definition of the parameter tan beta.

  15. One-Loop Helicity Amplitudes for tt Production at Hadron Colliders

    SciTech Connect

    Badger, Simon; Sattler, Ralf; Yundin, Valery

    2011-04-01

    We present compact analytic expressions for all one-loop helicity amplitudes contributing to tt production at hadron colliders. Using recently developed generalized unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation.

  16. One-loop modified gravity in a de Sitter universe, quantum-corrected inflation, and its confrontation with the Planck result

    NASA Astrophysics Data System (ADS)

    Bamba, Kazuharu; Cognola, Guido; Odintsov, Sergei D.; Zerbini, Sergio

    2014-07-01

    Motivated by issues on inflation, a generalized modified gravity model is investigated, where the model Lagrangian is described by a smooth function f(R,K,ϕ) of the Ricci scalar R, the kinetic term K of a scalar field ϕ. In particular, the one-loop effective action in the de Sitter background is examined on shell as well as off shell in the Landau gauge. In addition, the on-shell quantum equivalence of f(R) gravity in the Jordan and Einstein frames is explicitly demonstrated. Furthermore, we present applications related to the stability of the de Sitter solutions and the one-loop quantum correction to inflation in quantum-corrected R2 gravity. It is shown that, for a certain range of parameters, the spectral index of the curvature perturbations can be consistent with the Planck analysis, but the tensor-to-scalar ratio is smaller than the minimum value within the 1σ error range of the BICEP2 result.

  17. The pentagon relation and incidence geometry

    SciTech Connect

    Doliwa, Adam; Sergeev, Sergey M.

    2014-06-01

    We define a map S:D²×D²→D²×D², where D is an arbitrary division ring (skew field), associated with the Veblen configuration, and we show that such a map provides solutions to the functional dynamical pentagon equation. We explain that fact in elementary geometric terms using the symmetry of the Veblen and Desargues configurations. We introduce also another map of a geometric origin with the pentagon property. We show equivalence of these maps with recently introduced Desargues maps which provide geometric interpretation to a non-commutative version of Hirota's discrete Kadomtsev–Petviashvili equation. Finally, we demonstrate that in an appropriate gauge the (commutative version of the) maps preserves a natural Poisson structure—the quasiclassical limit of the Weyl commutation relations. The corresponding quantum reduction is then studied. In particular, we discuss uniqueness of the Weyl relations for the ultra-local reduction of the map. We give then the corresponding solution of the quantum pentagon equation in terms of the non-compact quantum dilogarithm function.

  18. Systematic study of the d = 5 Weinberg operator at one-loop order

    NASA Astrophysics Data System (ADS)

    Bonnet, Florian; Hirsch, Martin; Ota, Toshihiko; Winter, Walter

    2012-07-01

    We perform a systematic study of the d = 5 Weinberg operator at the one-loop level. We identify three different categories of neutrino mass generation: (1) finite irreducible diagrams; (2) finite extensions of the usual seesaw mechanisms at one-loop and (3) divergent loop realizations of the seesaws. All radiative one-loop neutrino mass models must fall into one of these classes. Case (1) gives the leading contribution to neutrino mass naturally and a classic example of this class is the Zee model. We demonstrate that in order to prevent that a tree level contribution dominates in case (2), Majorana fermions running in the loop and an additional {Z_2} symmetry are needed for a genuinely leading one-loop contribution. In the type-II loop extensions, the Yukawa coupling will be generated at one loop, whereas the type-I/III extensions can be interpreted as loop-induced inverse or linear seesaw mechanisms. For the divergent diagrams in category (3), the tree level contribution cannot be avoided and is in fact needed as counter term to absorb the divergence.

  19. One-loop calculations in quantum field theory: from Feynman diagrams to unitarity cuts

    SciTech Connect

    Ellis, R. Keith; Kunszt, Zoltan; Melnikov, Kirill; Zanderighi, Giulia

    2012-09-01

    The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of one-loop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.

  20. A Proposal for a Standard Interface Between Monte Carlo Tools And One-Loop Programs

    SciTech Connect

    Binoth, T.; Boudjema, F.; Dissertori, G.; Lazopoulos, A.; Denner, A.; Dittmaier, S.; Frederix, R.; Greiner, N.; Hoeche, Stefan; Giele, W.; Skands, P.; Winter, J.; Gleisberg, T.; Archibald, J.; Heinrich, G.; Krauss, F.; Maitre, D.; Huber, M.; Huston, J.; Kauer, N.; Maltoni, F.; /Louvain U., CP3 /Milan Bicocca U. /INFN, Turin /Turin U. /Granada U., Theor. Phys. Astrophys. /CERN /NIKHEF, Amsterdam /Heidelberg U. /Oxford U., Theor. Phys.

    2011-11-11

    Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarises the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV Colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.

  1. One-loop F(R, P, Q) gravity in de Sitter universe

    NASA Astrophysics Data System (ADS)

    Cognola, Guido; Zerbini, Sergio

    2012-09-01

    Motivated by the dark energy issue, the one-loop quantization approach for a class of relativistic higher order theories is discussed in some detail. A specific F(R, P, Q) gravity model at the one-loop level in a de Sitter universe is investigated, extending the similar program developed for the case of F(R) gravity. The stability conditions under arbitrary perturbations are derived. 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’.

  2. Bond resonance energy and verification of the isolated pentagon rule

    SciTech Connect

    Aihara, Jun Ichi

    1995-04-12

    The isolated pentagon rule (IPR) states that fullerenes with isolated pentagons are kinetically much more stable than their fused pentagon counterparts. This rule can be verified in terms of a graph-theoretically defined bond resonance energy. In general, a {pi} bond shared by two pentagons has a large negative bond resonance energy, thus contributing significantly to the increase in kinetic instability or chemical reactivity of the molecule. The existence of such highly antiaromatic local structures sharply distinguishes IPR-violating fullerenes from isolated-pentagon isomers. {pi}bonds shared by two pentagons are shared by many antiaromatic conjugated circuits but not by relatively small aromatic conjugated circuits. 39 refs., 3 figs., 5 tabs.

  3. One-loop quantum electrodynamic correction to the gravitational potentials on de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Wang, C. L.; Woodard, R. P.

    2015-10-01

    We compute the one-loop photon contribution to the graviton self-energy on a de Sitter background and use it to solve the linearized Einstein equation for a point mass. Our results show that a comoving observer sees a logarithmic spatial running Newton's constant. Equivalently, a static observer reports a secular suppression of the Newtonian potential.

  4. Numerical evaluation of one-loop diagrams near exceptional momentum configurations

    SciTech Connect

    Walter T Giele; Giulia Zanderighi; E.W.N. Glover

    2004-07-06

    One problem which plagues the numerical evaluation of one-loop Feynman diagrams using recursive integration by part relations is a numerical instability near exceptional momentum configurations. In this contribution we will discuss a generic solution to this problem. As an example we consider the case of forward light-by-light scattering.

  5. Towards the one-loop Kähler metric of Calabi-Yau orientifolds

    NASA Astrophysics Data System (ADS)

    Berg, Marcus; Haack, Michael; Kang, Jin U.; Sjörs, Stefan

    2014-12-01

    We evaluate string one-loop contributions to the Kähler metric of closed string moduli in toroidal minimally supersymmetric (Calabi-Yau) orientifolds with D-branes. We focus on the poorly understood = 1 sectors that receive contributions from all massive string states.

  6. Renovating the Pentagon's heating and refrigeration plant

    SciTech Connect

    Snyder, G.C. Jr. )

    1992-07-01

    This paper reports that the Pentagon heating plant originally burned coal, but has since been converted to natural gas and oil. Fifty years of service have caught up with the facility and now none of the five original boilers remains operational. Much of the old coal and ash handling equipment remain in the plant but have not been used since the conversion from coal. The inoperative conveyors and bins stand in silent testimony to a time of simpler environmental and licensing concerns. Rented, temporary, trailer-mounted boilers now supply most of the heating needs. The existing plant is on a small site about 1,500 ft (460 m) southeast of the Pentagon. Chilled water and steam are supplied to the Pentagon through steel piping in an underground concrete tunnel. Chilled water and steam are also supplied to Federal Office Building 2 (FOB-2) and Henderson Hall. FOB-2 is a 1,028,000 ft{sup 2} (95,500 m{sup 2}) office building now used by the U.S. Navy. Henderson Hall (steam only) is a 22 acre (8.9 hectares) complex of buildings that serves elements of the headquarters of the U.S. Marine Corps. FOB-2 and Henderson Hall are situated on the far west side of the Pentagon from the central plant. This necessitates piping runs of over 7,000 ft (2,100 m) one way. Distribution of chilled water is now made using a radial arrangement of progressively smaller lines that branch from the single 36 in. (91 cm) supply and return mains from the plant. A single 24 in. (61 cm) branch conveys chilled water to FOB-2 using the central plant pumps. The existing heating distribution also is a radial arrangement that conveys saturated steam at 125 psig (860 kPa). The system's age and inefficiency are exhibited by the need to have a makeup water rate that is, at times, 50% of the total steam delivery rate.

  7. Massive basketball diagram for a thermal scalar field theory

    NASA Astrophysics Data System (ADS)

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-01

    The ``basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a φ4 interaction to three-loop order.

  8. Constructing I[subscript h] Symmetrical Fullerenes from Pentagons

    ERIC Educational Resources Information Center

    Gan, Li-Hua

    2008-01-01

    Twelve pentagons are sufficient and necessary to form a fullerene cage. According to this structural feature of fullerenes, we propose a simple and efficient method for the construction of I[subscript h] symmetrical fullerenes from pentagons. This method does not require complicated mathematical knowledge; yet it provides an excellent paradigm for…

  9. Pentagon Spending on Research Sees Largest Increase in a Decade.

    ERIC Educational Resources Information Center

    Brainard, Jeffrey

    1999-01-01

    Examines trends in Pentagon support of campus-based military research and reports that lawmakers gave the Defense Department a science budget 11 percent higher in 2000 than in 1999. Notes critics' concerns about Pentagon priorities versus the nation's science needs and lobbying by university and industry groups in the Coalition for National…

  10. Quantum magnetic flux lines, BPS vortex zero modes, and one-loop string tension shifts

    NASA Astrophysics Data System (ADS)

    Alonso-Izquierdo, A.; Mateos Guilarte, J.; de la Torre Mayado, M.

    2016-08-01

    Spectral heat kernel/zeta function regularization procedures are employed in this paper to control the divergences arising from vacuum fluctuations of Bogomolnyi-Prasad-Sommerfield vortices in the Abelian Higgs model. Zero modes of vortex fluctuations are the source of difficulties appearing when the standard Gilkey-de Witt expansion is the tool used in the calculations of one-loop shifts of vortex masses and string tensions. A modified GdW expansion is developed to diminish the impact of the infrared divergences due to the vortex zero modes of fluctuation. With this new technique at our disposal we compute the one-loop vortex mass shifts in the planar AHM and the quantum corrections to the string tension of the magnetic flux tubes living in three dimensions. In both cases it is observed that weak repulsive forces surge between these classically noninteracting topological defects caused by vacuum quantum fluctuations.

  11. String-inspired BCJ numerators for one-loop MHV amplitudes

    NASA Astrophysics Data System (ADS)

    He, Song; Monteiro, Ricardo; Schlotterer, Oliver

    2016-01-01

    We find simple expressions for the kinematic numerators of one-loop MHV amplitudes in maximally supersymmetric Yang-Mills theory and supergravity, at any multiplicity. The gauge-theory numerators satisfy the Bern-Carrasco-Johansson (BCJ) duality between color and kinematics, so that the gravity numerators are simply the square of the gauge-theory ones. The duality holds because the numerators can be written in terms of structure constants of a kinematic algebra, which is familiar from the BCJ organization of self-dual gauge theory and gravity. The close connection that we find between one-loop amplitudes in the self-dual case and in the maximally supersymmetric case is reminiscent of the dimension-shifting formula. The starting point for arriving at our expressions is the dimensional reduction of ten-dimensional amplitudes obtained in the field-theory limit of open superstrings.

  12. Relic density at one-loop with gauge boson pair production

    SciTech Connect

    Baro, N.; Boudjema, F.; Chalons, G.; Hao Sun

    2010-01-01

    We have computed the full one-loop corrections (electroweak as well as QCD) to processes contributing to the relic density of dark matter in the minimal supersymmetric standard model where the lightest supersymmetric particle is the lightest neutralino. We cover scenarios where the most important channels are those with gauge boson pair production. This includes the case of a bino with some wino admixture, a Higgsino and a wino. In this paper we specialize to the case of light dark matter much below the TeV scale. The corrections can have a non-negligible impact on the predictions and should be taken into account in view of the present and forthcoming increasing precision on the relic density measurements. Our calculations are made with the help of SLOOPS, an automatic tool for the calculation of one-loop processes in the minimal supersymmetric standard model. The renormalization scheme dependence of the results as concerns tan{beta} is studied.

  13. All One-loop Maximally Helicity Violating Gluonic Amplitudes in QCD

    SciTech Connect

    Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren; Kosower, David A.

    2006-07-05

    We use on-shell recursion relations to compute analytically the one-loop corrections to maximally-helicity-violating n-gluon amplitudes in QCD. The cut-containing parts have been computed previously; our work supplies the remaining rational parts for these amplitudes, which contain two gluons of negative helicity and the rest positive, in an arbitrary color ordering. We also present formulae specific to the six-gluon cases, with helicities (-+-+++) and (-++-++), as well as numerical results for six, seven, and eight gluons. Our construction of the n-gluon amplitudes illustrates the relatively modest growth in complexity of the on-shell-recursive calculation as the number of external legs increases. These amplitudes add to the growing body of one-loop amplitudes known for all n, which are useful for studies of general properties of amplitudes, including their twistor-space structure.

  14. Threshold pp-->ppπ0 up to one-loop accuracy

    NASA Astrophysics Data System (ADS)

    Ando, S.; Park, T.-S.; Min, D.-P.

    2001-06-01

    The pp-->ppπ0 cross section near threshold is computed up to one-loop order including the initial and final state interactions using the hybrid heavy baryon chiral perturbation theory and the counting rule a la Weinberg. With the counter terms whose coefficients are fixed by the resonance-saturation assumption, we find that the one-loop contributions are as important as the tree-order contribution and bring the present theoretical estimation of the total cross section close to the experimental data. The short-ranged contributions are controlled by means of a cutoff, and a mild cutoff dependence is observed when all diagrams of the given chiral order are summed. To the order treated, however, the expansion is found to converge rather slowly, calling for further studies of the process.

  15. Complete one-loop electroweak corrections to ZZZ production at the ILC

    NASA Astrophysics Data System (ADS)

    Ji-Juan, Su; Wen-Gan, Ma; Ren-You, Zhang; Shao-Ming, Wang; Lei, Guo

    2008-07-01

    We study the complete O(αew) electroweak (EW) corrections to the production of three Z0 bosons in the framework of the standard model (SM) at the ILC. The leading-order and the EW next-to-leading-order corrected cross sections are presented, and their dependence on the colliding energy s and Higgs-boson mass mH is analyzed. We investigate also the LO and one-loop EW corrected distributions of the transverse momentum of the final Z0 boson, and the invariant mass of the Z0Z0 pair. Our numerical results show that the EW one-loop correction generally suppresses the tree-level cross section, and the relative correction with mH=120GeV(150GeV) varies between -15.8%(-13.9%) and -7.5%(-6.2%) when s goes up from 350 GeV to 1 TeV.

  16. Package-X: A Mathematica package for the analytic calculation of one-loop integrals

    NASA Astrophysics Data System (ADS)

    Patel, Hiren H.

    2015-12-01

    Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of UV divergent, IR divergent, and finite parts for any kinematic configuration involving real-valued external invariants and internal masses. Output expressions can be readily evaluated numerically and manipulated symbolically with built-in Mathematica functions. Emphasis is on evaluation speed, on readability of results, and especially on user-friendliness. Also included is a routine to compute traces of products of Dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one-loop. The package is intended to be used both as a research tool and as an educational tool.

  17. One-Loop Multi-Parton Amplitudes with a Vector Boson for the LHC

    SciTech Connect

    Berger, C.F.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Forde, D.; Ita, H.; Kosower, D.A.; Maitre, D.; /SLAC

    2008-08-11

    In this talk, we present the first, numerically stable, results for the one-loop amplitudes needed for computing W; Z + 3 jet cross sections at the LHC to next-to-leading order in the QCD coupling. We implemented these processes in BlackHat, an automated program based on on-shell methods. These methods scale very well with increasing numbers of external partons, and are applicable to a wide variety of problems of phenomenological interest at the LHC.

  18. One-loop fluctuation-dissipation formula for bubble-wall velocity

    SciTech Connect

    Arnold, P.

    1993-06-01

    The limiting bubble wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. It is demonstrated that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas limit.

  19. Symmetry breaking and restoration for interacting scalar and gauge fields in Lifshitz type theories

    NASA Astrophysics Data System (ADS)

    Farakos, K.; Metaxas, D.

    2012-05-01

    We consider the one-loop effective potential at zero and finite temperature in field theories with anisotropic space-time scaling, with critical exponent z = 2, including both scalar and gauge fields. Depending on the relative strength of the coupling constants for the gauge and scalar interactions, we find that there is a symmetry breaking term induced at one loop at zero temperature and we find symmetry restoration through a first-order phase transition at high temperature.

  20. Capturing the Fused-Pentagon C74 by Stepwise Chlorination.

    PubMed

    Gao, Cong-Li; Abella, Laura; Tan, Yuan-Zhi; Wu, Xin-Zhou; Rodríguez-Fortea, Antonio; Poblet, Josep M; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2016-07-18

    As a bridge to connect medium-sized fullerenes, fused-pentagon C74 is still missing heretofore. Of 14 246 possible isomers, the first fused-pentagon C74 with the Fowler-Manolopoulos code of 14 049 was stabilized as C74Cl10 in the chlorine-involving carbon arc. The structure of C74Cl10 was identified by X-ray crystallography. The stabilization of pristine fused-pentagon C74 by stepwise chlorination was clarified in both theoretical simulation with density functional theory calculations and experimental fragmentation with multistage mass spectrometry. PMID:27341488

  1. Radiative corrections to the non commutative photon propagator at one-loop order

    SciTech Connect

    Boutalbi, E.; Kouadik, S.

    2012-06-27

    We study the non-commutative gauge theory on the Moyal space. We add the harmonic potential introduced by Grosse and Wulkenhaar to the Maxwell Lagrange as well as the Gauge fixation. We determine the non-commutative U{sub *}(1) Gauge action which is invariant under the BRST transformations in the matrix basis. We determine in this basis the quadratic parts and the vertex of the Gauge field A{sub {mu}} and of the Faddeev-Popov ghost fields c(bar sign)andc. Finally, we study the perturbative correction to one loop order of the one point function in the matrix basis.

  2. A FDR-Preserving Field Theory for Interacting Brownian Particles: One-Loop Theory and MCT

    SciTech Connect

    Kim, Bongsoo; Kawasaki, Kyozi

    2008-02-21

    We develop a field theoretical treatment of a model of interacting Brownian particles. We pay particlular attention to the requirement of the time reversal (TR) invariance and the flucutation-dissipation relationship (FDR). Previous field theoretical formulations were found to be inconsistent with this requirement. The method used in the present formulation is a modified version of the auxilliary field method due originally to Andreanov, Biroli and Lefevre (ABL). We recover the correct diffusion law when the interaction is dropped as well as the standard mode coupling equation in the one-loop order calculation for interacting Brownian particle systems.

  3. One loop graviton self-energy in a locally de Sitter background

    SciTech Connect

    tSAMIS, n.c. |; Woodard, R.P.

    1996-02-01

    The graviton tadpole has recently been computed at two loops in a locally de Sitter background. We apply intermediate results of this work to exhibit the graviton self-energy at one loop. This quantity is interesting both to check the accuracy of the first calculation and to understand the relaxation effect it reveals. In the former context we show that the self-energy obeys the appropriate Ward identity. We also show that its flat space limit agrees with the flat space result obtained by Capper in what should be the same gauge. 15 refs., 4 figs., 10 tabs.

  4. Supermatrix proper-time representation of one-loop effective action and gauge invariance

    SciTech Connect

    Min, H. ); Lee, C. )

    1990-01-15

    Starting from the supermatrix proper-time representation, we construct the gauge-invariant one-loop effective action for generic renormalizable field theories involving spin-0, -1/2, and -1 fields in flat or curved spacetime. In the presence of fermion couplings involving the {gamma}{sub 5} matrix (but the theory having no genuine gauge anomaly), gauge invariance requires that the usual ultraviolet renormalization procedure be supplemented by appropriate finite renormalization terms. The supermatrix method is very convenient for finding the finite renormalization terms associated with vertex functions involving some external fermion legs.

  5. VIEW SOUTH TOWARD MOVEABLE FIELD LEVEL SEATS. NOTE RETRACTABLE PENTAGONAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW SOUTH TOWARD MOVEABLE FIELD LEVEL SEATS. NOTE RETRACTABLE PENTAGONAL LIGHT RING GONDOLA SUSPENDED FROM ROOF CUPOLA. SKY LIGHTS PAINTED OVER TO REDUCE GLARE FOR BASEBALL OUTFIELDERS. - Houston Astrodome, 8400 Kirby Drive, Houston, Harris County, TX

  6. The concept of 'giftedness': a pentagonal implicit theory.

    PubMed

    Sternberg, R J

    1993-01-01

    This paper presents a pentagonal implicit theory of giftedness and a set of data testing the theory. The exposition is divided into five parts. First, I discuss what an implicit theory is and why such theories are important. Second, I describe the pentagonal theory, specifying five conditions claimed to be individually necessary and jointly sufficient for a person to be labelled as gifted. These conditions not only help us understand why some people are labelled as 'gifted', but also why some others are not. Third, I consider the relation of the pentagonal theory to explicit theories of giftedness. Fourth, I present data supporting the theory. Finally, I discuss some implications of the pentagonal theory for gifted education.

  7. 70. AERIAL VIEW OF ROUTE 110 WITH PENTAGON AND PARKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. AERIAL VIEW OF ROUTE 110 WITH PENTAGON AND PARKING AREA LOOKING SOUTHEAST.(EXPRESSWAY V.S. PARKWAY) - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

  8. Hartree approximation to the one loop quantum gravitational correction to the graviton mode function on de Sitter

    SciTech Connect

    Mora, P.J.; Woodard, R.P.; Tsamis, N.C. E-mail: tsamis@physics.uoc.gr

    2013-10-01

    We use the Hartree approximation to the Einstein equation on de Sitter background to solve for the one loop correction to the graviton mode function. This should give a reasonable approximation to how the ensemble of inflationary gravitons affects a single external graviton. At late times we find that the one loop correction to the plane wave mode function u(η,k) goes like GH{sup 2}ln (a)/a{sup 2}, where a is the inflationary scale factor. One consequence is that the one loop corrections to the ''electric'' components of the linearized Weyl tensor grow compared to the tree order result.

  9. Functionalization of pentagon-pentagon edges of fullerenes by cyclic polysulfides: A DFT study

    NASA Astrophysics Data System (ADS)

    Anafcheh, Maryam; Khodadadi, Zahra; Ektefa, Fatemeh; Ghafouri, Reza

    2016-05-01

    We have performed a computational study to investigate the cyclosulfurization of the pentagon-pentagon (p-p) junctions in the non-IPR fullerenes C60(D3) and C70(C2v), and also Stone-Wales defective C60 fullerene. Our results indicate the exothermic character of cyclosulfurization processes which can be related to the increase of pyramidalization angle (spherical excesses) and p characters of natural hybrid orbitals of C atoms at the p-p junctions. In fact these lead to the structural strain relief and stability of the cyclosulfurization derivatives of the non-IPR fullerenes. Moreover, the cyclosulfurization reaction of p-p bonds on the C70(C2v) is more energetically favorable than that of C60(D3), due to the higher curvature of carbon sites and the larger values of the p characters of natural hybrid orbitals in the C70(C2v). On the other hand, localization of the excess electrons on the C atoms at the p-p junctions leads to the low tendency of the charged non-IPR fullerenes to cyclosulfurization process. The desulfurization pathway of the exohedral derivatives of C70(C2v) indicates that it is energetically unfavorable for the functionalized fullerenes to break into individual fullerene and sulfur molecules. HOMO-LUMO gaps almost are independent of the number of pentathiepin rings while sensitive to the type of parent fullerene.

  10. Complete spectrum of long operators in Script N = 4 SYM at one loop

    NASA Astrophysics Data System (ADS)

    Beisert, Niklas; Kazakov, Vladimir A.; Sakai, Kazuhiro; Zarembo, Konstantin

    2005-07-01

    We construct the complete spectral curve for an arbitrary local operator, including fermions and covariant derivatives, of one-loop Script N = 4 gauge theory in the thermodynamic limit. This curve perfectly reproduces the Frolov-Tseytlin limit of the full spectral curve of classical strings on AdS5 × S5 derived in [64]. To complete the comparison we introduce stacks, novel bound states of roots of different flavors which arise in the thermodynamic limit of the corresponding Bethe ansatz equations. We furthermore show the equivalence of various types of Bethe equations for the underlying fraktur sfraktur u(2,2|4) superalgebra, in particular of the type ``Beauty'' and ``Beast''.

  11. Spinning strings at one-loop in AdS4 × Bbb P3

    NASA Astrophysics Data System (ADS)

    McLoughlin, Tristan; Roiban, Radu

    2008-12-01

    We analyze the folded spinning string in AdS4 × Bbb P3 with spin S in AdS4 and angular momentum J in Bbb P3. We calculate the one-loop correction to its energy in the scaling limit of both ln S and J large with their ratio kept fixed. This result should correspond to the first subleading strong coupling correction to the anomalous dimension of operators of the type Tr(DS(Y†Y)J) in the dual Script N = 6 Chern-Simons-matter theory. Our result appears to depart from the predictions for the generalized scaling function found from the all-loop Bethe equations conjectured for this AdS4/CFT3 duality. We comment on the possible origin of this difference.

  12. 2D quantum gravity at one loop with Liouville and Mabuchi actions

    NASA Astrophysics Data System (ADS)

    Bilal, Adel; Ferrari, Frank; Klevtsov, Semyon

    2014-03-01

    We study a new two-dimensional quantum gravity theory, based on a gravitational action containing both the familiar Liouville term and the Mabuchi functional, which has been shown to be related to the coupling of non-conformal matter to gravity. We compute the one-loop string susceptibility from a first-principle, path integral approach in the Kähler parameterization of the metrics and discuss the particularities that arise in the case of the pure Mabuchi theory. While we mainly use the most convenient spectral cutoff regularization to perform our calculations, we also discuss the interesting subtleties associated with the multiplicative anomaly in the familiar ζ-function scheme, which turns out to have a genuine physical effect for our calculations. In particular, we derive and use a general multiplicative anomaly formula for Laplace-type operators on arbitrary compact Riemann surfaces.

  13. One-loop superstring six-point amplitudes and anomalies in pure spinor superspace

    NASA Astrophysics Data System (ADS)

    Mafra, Carlos R.; Schlotterer, Oliver

    2016-04-01

    We present the massless six-point one-loop amplitudes in the open and closed superstring using BRST cohomology arguments from the pure spinor formalism. The hexagon gauge anomaly is traced back to a class of kinematic factors in pure spinor superspace which were recently introduced as BRST pseudo-invariants. This complements previous work where BRST invariance arguments were used to derive the non-anomalous part of the amplitude. The associated worldsheet functions are non-singular and demonstrated to yield total derivatives on moduli space upon gauge variation. These cohomology considerations yield an efficient organizing principle for closed-string amplitudes that match expectations from S-duality in the low-energy limit.

  14. Impacts of biasing schemes in the one-loop integrated perturbation theory

    NASA Astrophysics Data System (ADS)

    Matsubara, Takahiko; Desjacques, Vincent

    2016-06-01

    The impact of biasing schemes on the clustering of tracers of the large-scale structure is analytically studied in the weakly nonlinear regime. For this purpose, we use the one-loop approximation of the integrated perturbation theory together with the renormalized bias functions of various, physically motivated Lagrangian bias schemes. These include the halo, peaks, and excursion set peaks model, for which we derive useful formulas for the evaluation of their renormalized bias functions. The shapes of the power spectra and correlation functions are affected by the different bias models at the level of a few percent on weakly nonlinear scales. These effects are studied quantitatively both in real and redshift space. The amplitude of the scale-dependent bias in the presence of primordial non-Gaussianity also depends on the details of the bias models. If left unaccounted for, these theoretical uncertainties could affect the robustness of the cosmological constraints extracted from galaxy clustering data.

  15. Bloch-Nordsieck thermometers: one-loop exponentiation in finite temperature QED

    NASA Astrophysics Data System (ADS)

    Gupta, Sourendu; Indumathi, D.; Mathews, Prakash; Ravindran, V.

    1996-02-01

    We study the scattering of hard external particles in a heat bath in a real-time formalism for finite temperature QED. We investigate the distribution of the 4-momentum difference of initial and final hard particles in a fully covariant manner when the scale of the process, Q, is much larger than the temperature, T. Our computations are valid for all T subject to this constraint. We exponentiate the leading infra-red term at one-loop order through a resummation of soft (thermal) photon emissions and absorptions. For T > 0, we find that tensor structures arise which are not present at T = 0. These cant' thermal signatures. As a result, external particles can serve as thermometers introduced into the heat bath. We investigate the phase space origin of log( Q/ m) and log ( Q/ T) teens.

  16. Integrated perturbation theory and one-loop power spectra of biased tracers

    NASA Astrophysics Data System (ADS)

    Matsubara, Takahiko

    2014-08-01

    General and explicit predictions from the integrated perturbation theory (iPT) for power spectra and correlation functions of biased tracers are derived and presented in the one-loop approximation. The iPT is a general framework of the nonlinear perturbation theory of cosmological density fields in the presence of nonlocal bias, redshift-space distortions, and primordial non-Gaussianity. Analytic formulas of auto and cross power spectra of nonlocally biased tracers in both real and redshift spaces are derived and the results are comprehensively summarized. The main difference from previous formulas derived by the present author is to include the effects of generally nonlocal Lagrangian bias and primordial non-Gaussianity, and the derivation method of the new formula is fundamentally different from the previous one. Relations to recent work on improved methods of nonlinear perturbation theory in the literature are clarified and discussed.

  17. The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures

    DOE PAGES

    Angulo, Raul E.; Foreman, Simon; Schmittfull, Marcel; Senatore, Leonardo

    2015-10-14

    With this study, given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/kNL, where k is the wavenumber of interest and kNL is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k ≃ 0.3 hmore » Mpc–1 and k ≃ 0.6 h Mpc–1 at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which kNL is smaller than in the previously considered cases (σ8=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k ≃ 0.25 h Mpc–1, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k ≃ 0.25 h Mpc–1, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.« less

  18. Scalar explanation of diphoton excess at LHC

    NASA Astrophysics Data System (ADS)

    Han, Huayong; Wang, Shaoming; Zheng, Sibo

    2016-06-01

    Inspired by the diphoton signal excess observed in the latest data of 13 TeV LHC, we consider either a 750 GeV real scalar or pseudo-scalar responsible for this anomaly. We propose a concrete vector-like quark model, in which the vector-like fermion pairs directly couple to this scalar via Yukawa interaction. For this setting the scalar is mainly produced via gluon fusion, then decays at the one-loop level to SM diboson channels gg , γγ , ZZ , WW. We show that for the vector-like fermion pairs with exotic electric charges, such model can account for the diphoton excess and is consistent with the data of 8 TeV LHC simultaneously in the context of perturbative analysis.

  19. Lagrangian perturbations and the matter bispectrum II: the resummed one-loop correction to the matter bispectrum

    SciTech Connect

    Rampf, Cornelius; Wong, Yvonne Y.Y. E-mail: yvonne.wong@physik.rwth-aachen.de

    2012-06-01

    This is part two in a series of papers in which we investigate an approach based on Lagrangian perturbation theory (LPT) to study the non-linear evolution of the large-scale structure distribution in the universe. Firstly, we compute the matter bispectrum in real space using LPT up one-loop order, for both Gaussian and non-Gaussian initial conditions. In the initial position limit, we find that the one-loop bispectrum computed in this manner is identical to its counterpart obtained from standard Eulerian perturbation theory (SPT). Furthermore, the LPT formalism allows for a simple reorganisation of the perturbative series corresponding to the resummation of an infinite series of perturbations in SPT. Applying this method, we find a resummed one-loop bispectrum that compares favourably with results from N-body simulations. We generalise the resummation method also to the computation of the redshift-space bispectrum up to one loop.

  20. Scalar field equations from quantum gravity during inflation

    SciTech Connect

    Kahya, E. O.; Woodard, R. P.

    2008-04-15

    We exploit a previous computation of the self-mass-squared from quantum gravity to include quantum corrections to the scalar evolution equation. The plane wave mode functions are shown to receive no significant one loop corrections at late times. This result probably applies as well to the inflaton of scalar-driven inflation. If so, there is no significant correction to the {phi}{phi} correlator that plays a crucial role in computations of the power spectrum.

  1. The maximum pentagon separation rule provides a guideline for the structures of endohedral metallofullerenes

    NASA Astrophysics Data System (ADS)

    Rodríguez-Fortea, Antonio; Alegret, Núria; Balch, Alan L.; Poblet, Josep M.

    2010-11-01

    Fullerenes tend to follow the isolated pentagon rule, which requires that each of the 12 pentagons is surrounded only by hexagons. Over the past decade many violations to this rule were reported for endohedral fullerenes. Based on the ionic model M3N6+@C2n6- and the orbital energies of the isolated cages, in 2005 we formulated a molecular orbital rule to identify the most suitable hosting cages in endohedral metallofullerenes. Now, we give physical support to the orbital rule, and we propose the maximum pentagon separation rule, which can be applied to either isolated pentagon rule cages or to non-isolated pentagon rule cages with the same number of adjacent pentagon pairs. The maximum pentagon separation rule can be formulated as 'The electron transfer from the internal cluster to the fullerene host preferentially adds electrons to the pentagons; therefore, the most suitable carbon cages are those with the largest separations among the 12 pentagons'.

  2. The maximum pentagon separation rule provides a guideline for the structures of endohedral metallofullerenes.

    PubMed

    Rodríguez-Fortea, Antonio; Alegret, Núria; Balch, Alan L; Poblet, Josep M

    2010-11-01

    Fullerenes tend to follow the isolated pentagon rule, which requires that each of the 12 pentagons is surrounded only by hexagons. Over the past decade many violations to this rule were reported for endohedral fullerenes. Based on the ionic model M(3)N(6+)@C(2n)(6-) and the orbital energies of the isolated cages, in 2005 we formulated a molecular orbital rule to identify the most suitable hosting cages in endohedral metallofullerenes. Now, we give physical support to the orbital rule, and we propose the maximum pentagon separation rule, which can be applied to either isolated pentagon rule cages or to non-isolated pentagon rule cages with the same number of adjacent pentagon pairs. The maximum pentagon separation rule can be formulated as 'The electron transfer from the internal cluster to the fullerene host preferentially adds electrons to the pentagons; therefore, the most suitable carbon cages are those with the largest separations among the 12 pentagons'.

  3. Radiative neutrino model with an inert triplet scalar

    NASA Astrophysics Data System (ADS)

    Okada, Hiroshi; Orikasa, Yuta

    2016-09-01

    We study a one-loop induced radiative neutrino model with an inert isospin triplet scalar field in the general framework of U (1 )Y , in which we discuss current neutrino oscillation data, lepton flavor violations, a muon anomalous magnetic moment, and a dark matter candidate depending on the number of hypercharges. We show global analysis combining all the constraints and discuss the model.

  4. The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures

    SciTech Connect

    Angulo, Raul E.; Foreman, Simon; Schmittfull, Marcel; Senatore, Leonardo

    2015-10-14

    With this study, given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/kNL, where k is the wavenumber of interest and kNL is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k ≃ 0.3 h Mpc–1 and k ≃ 0.6 h Mpc–1 at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which kNL is smaller than in the previously considered cases (σ8=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k ≃ 0.25 h Mpc–1, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k ≃ 0.25 h Mpc–1, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.

  5. One-loop Electroweak Radiative Corrections for Polarized Møller Scattering

    NASA Astrophysics Data System (ADS)

    Barkanova, Svetlana; Aleksejevs, Aleksandrs; Ilyichev, Alexander; Kolomensky, Yury; Zykunov, Vladimir

    2011-04-01

    Møller scattering measurements are a clean, powerful probe of new physics effects. However, before physics of interest can be extracted from the experimental data, radiative corrections must be taken into account very carefully. Using two different approaches, we perform updated and detailed calculations of the complete one-loop set of electroweak radiative corrections to parity violating electron-electron scattering asymmetry at low energies relevant for the ultra-precise 11 GeV MOLLER experiment planned at JLab. Although contributions from some of the self-energies and vertex diagrams calculated in the two approaches can differ significantly, our full gauge-invariant set still guarantees that the total relative weak corrections are in excellent agreement for the two methods of calculation. Our numerical results are presented for a range of experimental cuts and the relative importance of various contributions is analyzed. We also provide very compact expressions analytically free from non-physical parameters and show them to be valid for fast yet accurate estimations.

  6. Two aspects of one loop structure: Unitarity delay in the Standard Model and modular invariance in string theory

    SciTech Connect

    Ahn, C.

    1989-08-01

    We study two aspects of one loop structures in quantum field theories which describe two different areas of particle physics: the one loop unitarity behavior of the Standard Model of electroweak interactions and modular invariance of string model theory. Loop expansion has its importance in that it contains quantum fluctuations due to all physical states in the theory. Therefore, by studying the various models to one loop, we can understand how the contents of the theory can contribute to physically measurable quantities and how the consistency at quantum level restricts the physical states of the theory, as well. In the first half of the thesis, we study one loop corrections to the process {ital e}{sup +}{ital e}{sup {minus}} {yields} {ital W}{sup +}{ital W}{sup {minus}}. In this process, there is a delicate unitarity-saving cancellation between s-channel and t-channel tree level Feynman diagrams. If the one loop contribution due to heavy particles corrects the channels asymmetrically, the cancellation, hence unitarity, will be delayed up to the mass scale of these heavy particles. We refer to this phenomena as the unitarity delay effect. Due to this effect, cross section below these mass scales can have significant radiative corrections which may provide an appropriate window through which we can see the high energy structure of the Standard Model from relatively low energy experiments. In the second half, we will show how quantum consistency can restrict the physical states in string theory. 53 refs., 13 figs.

  7. A small-world and scale-free network generated by Sierpinski Pentagon

    NASA Astrophysics Data System (ADS)

    Chen, Jin; Le, Anbo; Wang, Qin; Xi, Lifeng

    2016-05-01

    The Sierpinski Pentagon is used to construct evolving networks, whose nodes are all solid regular pentagons in the construction of the Sierpinski Pentagon up to the stage t and any two nodes are neighbors if and only if the intersection of corresponding pentagons is non-empty and non-singleton. We show that such networks have the small-world and scale-free effects, but are not fractal scaling.

  8. Single pentagon in a hexagonal carbon lattice revealed by scanning tunneling microscopy

    SciTech Connect

    An, B.; Fukuyama, S.; Yokogawa, K.; Yoshimura, M.; Egashira, M.; Korai, Y.; Mochida, I.

    2001-06-04

    The electronic structure of a single pentagon in a hexagonal carbon lattice has been revealed on an atomic scale by scanning tunneling microscopy. The pentagon is located at the apex of the conical protuberance of the graphitic particle. The enhanced charge density localized at each carbon atom in the pentagon is identified, and the ringlike pattern of the ({radical}3{times}{radical}3)R30{degree} superstructure of graphite is clearly observed around the pentagon. {copyright} 2001 American Institute of Physics.

  9. Noncommutative scalar field minimally coupled to nonsymmetric gravity

    SciTech Connect

    Kouadik, S.; Sefai, D.

    2012-06-27

    We construct a non-commutative non symmetric gravity minimally coupled model (the star product only couples matter). We introduce the action for the system considered namely a non-commutative scalar field propagating in a nontrivial gravitational background. We expand the action in powers of the anti-symmetric field and the graviton to second order adopting the assumption that the scalar is weekly coupled to the graviton. We compute the one loop radiative corrections to the self-energy of a scalar particle.

  10. Massive basketball diagram for a thermal scalar field theory

    SciTech Connect

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-15

    The ''basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a {phi}{sup 4} interaction to three-loop order. (c) 2000 The American Physical Society.

  11. The Pentagon's Military Analyst Program

    ERIC Educational Resources Information Center

    Valeri, Andy

    2014-01-01

    This article provides an investigatory overview of the Pentagon's military analyst program, what it is, how it was implemented, and how it constitutes a form of propaganda. A technical analysis of the program is applied using the theoretical framework of the propaganda model first developed by Noam Chomsky and Edward S. Herman. Definitions…

  12. Pentagonal monolayer crystals of carbon, boron nitride, and silver azide

    SciTech Connect

    Yagmurcukardes, M. Senger, R. T.; Sahin, H.; Kang, J.; Torun, E.; Peeters, F. M.

    2015-09-14

    In this study, we present a theoretical investigation of structural, electronic, and mechanical properties of pentagonal monolayers of carbon (p-graphene), boron nitride (p-B{sub 2}N{sub 4} and p-B{sub 4}N{sub 2}), and silver azide (p-AgN{sub 3}) by performing state-of-the-art first principles calculations. Our total energy calculations suggest feasible formation of monolayer crystal structures composed entirely of pentagons. In addition, electronic band dispersion calculations indicate that while p-graphene and p-AgN{sub 3} are semiconductors with indirect bandgaps, p-BN structures display metallic behavior. We also investigate the mechanical properties (in-plane stiffness and the Poisson's ratio) of four different pentagonal structures under uniaxial strain. p-graphene is found to have the highest stiffness value and the corresponding Poisson's ratio is found to be negative. Similarly, p-B{sub 2}N{sub 4} and p-B{sub 4}N{sub 2} have negative Poisson's ratio values. On the other hand, the p-AgN{sub 3} has a large and positive Poisson's ratio. In dynamical stability tests based on calculated phonon spectra of these pentagonal monolayers, we find that only p-graphene and p-B{sub 2}N{sub 4} are stable, but p-AgN{sub 3} and p-B{sub 4}N{sub 2} are vulnerable against vibrational excitations.

  13. Spectral Signatures of the Pentagonal Water Cluster in Bacteriorhodopsin

    SciTech Connect

    Baer, Marcel; Mathias, Gerald; Kuo, I-F W.; Tobias, Douglas J.; Mundy, Christopher J.; Marx, Dominik

    2008-12-22

    We utilize QM/MM methodology with different size QM regions to elucidate the spectral fingerprint of the pentagonal water cluster in Bacteriorhodopsin. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

  14. One-loop gluon amplitude for heavy-quark production at next-to-next-to-leading order

    SciTech Connect

    Anastasiou, Charalampos; Aybat, S. Mert

    2008-12-01

    We compute the one-loop QCD amplitude for the process gg{yields}QQ in dimensional regularization through order {epsilon}{sup 2} in the dimensional regulator and for arbitrary quark mass values. This result is an ingredient of the next-to-next-to-leading order cross section for heavy-quark production at hadron colliders. The calculation is performed in conventional dimensional regularization using well-known reduction techniques as well as a method based on recent ideas for the functional form of one-loop integrands in four dimensions.

  15. Gamma-ray lines and one-loop continuum from s-channel dark matter annihilations

    SciTech Connect

    Jackson, C.B.; Servant, Géraldine; Shaughnessy, Gabe; Tait, Tim M.P.; Taoso, Marco E-mail: chris@uta.edu E-mail: ttait@uci.edu

    2013-07-01

    The era of indirect detection searches for dark matter has begun, with the sensitivities of gamma-ray detectors now approaching the parameter space relevant for weakly interacting massive particles. In particular, gamma ray lines would be smoking gun signatures of dark matter annihilation, although they are typically suppressed compared to the continuum. In this paper, we pay particular attention to the 1-loop continuum generated together with the gamma-ray lines and investigate under which conditions a dark matter model can naturally lead to a line signal that is relatively enhanced. We study generic classes of models in which DM is a fermion that annihilates through an s-channel mediator which is either a vector or scalar and identify the coupling and mass conditions under which large line signals occur. We focus on the ''forbidden channel mechanism'' advocated a few years ago in the ''Higgs in space'' scenario for which tree level annihilation is kinematically forbidden today. Detailed calculations of all 1-loop annihilation channels are provided. We single out very simple models with a large line over continuum ratio and present general predictions for a large range of WIMP masses that are relevant not only for Fermi and Hess II but also for the next generation of telescopes such as CTA and Gamma-400. Constraints from the relic abundance, direct detection and collider bounds are also discussed.

  16. Controlled synthesis of pentagonal gold nanotubes at room temperature.

    PubMed

    Bi, Yingpu; Lu, Gongxuan

    2008-07-01

    Large quantities of pentagonal gold nanotubes have been synthesized by reducing chloroauric acid with silver nanowires in an aqueous solution of hexadecyltrimethylammonium bromide (CTAB) at room temperature. These gold nanotubes possess perfect structures, smooth surfaces, highly crystalline walls, and similar cross-sections to that of the silver template. In this process, the CTAB participation was found to be crucial for shape-controlled synthesis of pentagonal gold nanotubes. In the absence of CTAB, loose and hollow gold structures were routinely generated, while bundled gold nanotubes with rough surfaces were obtained by replacing the CTAB with poly(vinyl pyrrolidone) (PVP). The possible formation mechanism of pentagonal gold nanotubes has also been discussed on the basis of various growth stages studied by field-emission scanning electron microscopy (FE-SEM) images. In addition, the catalytic properties of these hollow nanostructures for hydrogen generation reaction from HCHO solution have also been investigated. They showed higher activity than that of spherical gold nanoparticles. PMID:21828702

  17. Direct detection of the Wino and Higgsino-like neutralino dark matter at one-loop level

    SciTech Connect

    Hisano, Junji; Matsumoto, Shigeki; Saito, Osamu; Nojiri, Mihoko M.

    2005-01-01

    The neutralino-nucleon ({chi}-tilde{sup 0}-N) scattering is an important process for direct dark matter searches. In this paper we discuss one-loop contributions to the cross section in the winolike and Higgsino-like LSP cases. The neutralino-nucleon scattering mediated by the Higgs {chi}-tilde{sup 0}{chi}-tilde{sup 0} and Z{chi}-tilde{sup 0}{chi}-tilde{sup 0} couplings at tree level is suppressed by the gaugino-Higgsino mixing at tree-level when the neutralino is close to a weak eigenstate. The one-loop contribution to the cross section, generated by the gauge interaction, is not suppressed by any SUSY particle mass or mixing in the wino- and Higgsino-like LSP cases. It may significantly alter the total cross section when {sigma}{sub {chi}}{sub -tilde{sup 0}}{sub N}{approx}10{sup -45} cm{sup 2} or less.

  18. One-loop amplitudes of winding strings in AdS3 and the Coulomb gas approach

    NASA Astrophysics Data System (ADS)

    Giribet, Gaston

    2016-03-01

    We discuss a Coulomb gas realization of n -point correlation functions in the S L (2 ,R ) Wess-Zumino-Witten (WZW) model that is suitable to compute scattering amplitudes of winding strings in three-dimensional anti-de Sitter space at tree level and one loop. This is a refined version of previously proposed free-field realizations that, among other features, make the H3+ WZW-Liouville correspondence manifest.

  19. Three-loop radiative-recoil corrections to hyperfine splitting generated by one-loop fermion factors

    SciTech Connect

    Eides, Michael I.; Grotch, Howard; Shelyuto, Valery A.

    2004-10-01

    We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium generated by diagrams with one-loop radiative photon insertions both in the electron and muon lines. An analytic result for these nonlogarithmic corrections of order {alpha}(Z{sup 2}{alpha})(Z{alpha})(m/M)E{sub F} is obtained. This result constitutes a next step in the implementation of the program of reduction of the theoretical uncertainty of hyperfine splitting below 10 Hz.

  20. Full one-loop electroweak and NLO QCD corrections to the associated production of chargino and neutralino at hadron colliders

    SciTech Connect

    Sun Hao; Han Liang; Zhang Renyou; Jiang Yi; Guo Lei; Ma Wengan

    2006-03-01

    We study the process of the association production of chargino and neutralino including the next-to-leading order (NLO) QCD and the complete one-loop electroweak corrections in the framework of the minimal supersymmetric standard model at the Fermilab Tevatron and the CERN Large Hadron Collider. In both the NLO QCD and one-loop electroweak calculations we apply the algorithm of the phase-space slicing method. We find that the NLO QCD corrections generally increase the Born cross sections, while the electroweak relative corrections decrease the Born cross section in most of the chosen parameter space. The NLO QCD and electroweak relative corrections typically have the values of about 32% and -8% at the Tevatron, and about 42% and -6% at the Large Hadron Collider, respectively. The results show that both the NLO QCD and the complete one-loop electroweak corrections to the processes pp/pp{yields}{chi}-tilde{sub 1}{sup {+-}}{chi}-tilde{sub 2}{sup 0}+X are generally significant and should be taken into consideration in precision experimental analysis.

  1. Molecular structures of unstable isolated-pentagon-rule fullerenes C72-C86

    NASA Astrophysics Data System (ADS)

    Khamatgalimov, A. R.; Kovalenko, V. I.

    2016-08-01

    Published data on fullerenes C72 to C86 which obey the isolated pentagon rule (IPR) are generalized. Analysis of unstable isolated-pentagon-rule fullerenes is carried out and the instability criteria are formulated. Two main reasons for the instability of IPR fullerene molecules are identified: their radical nature and/or local overstrain. The classification of fullerenes and a revised isolated pentagon rule are presented. The bibliography includes 119 references.

  2. Study of symmetry breaking of charged scalar field: Hydrodynamic version

    NASA Astrophysics Data System (ADS)

    Matos, T.; Rodríguez-Meza, M. A.

    2014-11-01

    We rewrite the Klein-Gordon (KG) equation for a complex scalar field as a new Gross-Pitaevskii (GP)-like equation. The potential of the scalar field is a mexican-hat potential and the field is in a thermal bath with one loop contribution. We interpret the new GP equation as a finite temperature generalization of the GP equation for a charged field. We find its hydrodynamic version as well and using it, we derive the corresponding thermodynamics. We also obtain a generalized first law for a charged Bose-Einstein Condensate (BEC).

  3. Water-Soluble Pentagonal-Prismatic Titanium-Oxo Clusters.

    PubMed

    Zhang, Guanyun; Liu, Caiyun; Long, De-Liang; Cronin, Leroy; Tung, Chen-Ho; Wang, Yifeng

    2016-09-01

    By using solubility control to crystallize the prenucleation clusters of hydrosol, a family of titanium-oxo clusters possessing the {Ti18O27} core in which the 18 Ti(IV)-ions are uniquely connected with μ-oxo ligands into a triple-decked pentagonal prism was obtained. The cluster cores are wrapped by external sulfate and aqua ligands, showing good solubilities and stabilities in a variety of solvents including acetonitrile and water and allowing their solution chemistry being studied by means of electrospray ionization mass spectroscopy, (17)O NMR, and vibrational spectroscopy. Furthermore, this study provides new titanium oxide candidates for surface modifications and homogeneous photocatalysis. PMID:27525444

  4. HFOLD - A program package for calculating two-body MSSM Higgs decays at full one-loop level.

    PubMed

    Frisch, W; Eberl, H; Hluchá, H

    2011-10-01

    HFOLD (Higgs Full One Loop Decays) is a Fortran program package for calculating all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The package is done in the SUSY Parameter Analysis convention and supports the SUSY Les Houches Accord input and output format. PROGRAM SUMMARY: Program title: HFOLD Catalogue identifier: AEJG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 340 621 No. of bytes in distributed program, including test data, etc.: 1 760 051 Distribution format: tar.gz Programming language: Fortran 77 Computer: Workstation, PC Operating system: Linux RAM: 524 288 000 Bytes Classification: 11.1 External routines: LoopTools 2.2 (http://www.feynarts.de/looptools/), SLHALib 2.2 (http://www.feynarts.de/slha/). The LoopTools code is included in the distribution package. Nature of problem: A future high-energy e+e- linear collider will be the best environment for the precise measurements of masses, cross sections, branching ratios, etc. Experimental accuracies are expected at the per-cent down to the per-mile level. These must be matched from the theoretical side. Therefore higher order calculations are mandatory. Solution method: This program package calculates all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The renormalization is done in the DR scheme following the SUSY Parameter Analysis convention. The program supports the SUSY Les Houches Accord input and output format. Running time: The example provided takes only a few seconds to run. PMID:21969735

  5. HFOLD - A program package for calculating two-body MSSM Higgs decays at full one-loop level.

    PubMed

    Frisch, W; Eberl, H; Hluchá, H

    2011-10-01

    HFOLD (Higgs Full One Loop Decays) is a Fortran program package for calculating all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The package is done in the SUSY Parameter Analysis convention and supports the SUSY Les Houches Accord input and output format. PROGRAM SUMMARY: Program title: HFOLD Catalogue identifier: AEJG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 340 621 No. of bytes in distributed program, including test data, etc.: 1 760 051 Distribution format: tar.gz Programming language: Fortran 77 Computer: Workstation, PC Operating system: Linux RAM: 524 288 000 Bytes Classification: 11.1 External routines: LoopTools 2.2 (http://www.feynarts.de/looptools/), SLHALib 2.2 (http://www.feynarts.de/slha/). The LoopTools code is included in the distribution package. Nature of problem: A future high-energy e+e- linear collider will be the best environment for the precise measurements of masses, cross sections, branching ratios, etc. Experimental accuracies are expected at the per-cent down to the per-mile level. These must be matched from the theoretical side. Therefore higher order calculations are mandatory. Solution method: This program package calculates all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The renormalization is done in the DR scheme following the SUSY Parameter Analysis convention. The program supports the SUSY Les Houches Accord input and output format. Running time: The example provided takes only a few seconds to run.

  6. Charged Higgs Boson production at e^+e^- colliders in the complex MSSM: a full one-loop analysis

    NASA Astrophysics Data System (ADS)

    Heinemeyer, S.; Schappacher, C.

    2016-10-01

    For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector precise knowledge of their production properties is mandatory. We evaluate the cross sections for the charged Higgs boson production at e^+e^- colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism e^+e^- → H^+ H^- and e^+e^- → H^{± } W^{∓ }, including soft and hard QED radiation. The dependence of the Higgs boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many cross sections. They are, depending on the production channel, roughly of 5-10 % of the tree-level results, but can go up to 20 % or higher. The full one-loop contributions are important for a future linear e^+e^- collider such as the ILC or CLIC.

  7. Lattice Wess-Zumino model with Ginsparg-Wilson fermions: One-loop results and GPU benchmarks

    SciTech Connect

    Chen Chen; Dzienkowski, Eric; Giedt, Joel

    2010-10-15

    We numerically evaluate the one-loop counterterms for the four-dimensional Wess-Zumino model formulated on the lattice using Ginsparg-Wilson fermions of the overlap (Neuberger) variety, together with an auxiliary fermion (plus superpartners), such that a lattice version of U(1){sub R} symmetry is exactly preserved in the limit of vanishing bare mass. We confirm previous findings by other authors that at one loop there is no renormalization of the superpotential in the lattice theory, but that there is a mismatch in the wave-function renormalization of the auxiliary field. We study the range of the Dirac operator that results when the auxiliary fermion is integrated out, and show that localization does occur, but that it is less pronounced than the exponential localization of the overlap operator. We also present preliminary simulation results for this model, and outline a strategy for nonperturbative improvement of the lattice supercurrent through measurements of supersymmetry Ward identities. Related to this, some benchmarks for our graphics processing unit code are provided. Our simulation results find a nearly vanishing vacuum expectation value for the auxiliary field, consistent with approximate supersymmetry at weak coupling.

  8. One-Loop β Functions for Yukawa Couplings in the Electroweak-Scale Right-Handed Neutrino Model

    NASA Astrophysics Data System (ADS)

    Nhu Le, Nguyen; Quang Hung, Pham

    2014-09-01

    Fermions in the model of electroweak-scale right-handed neutrinos (EWRH) with masses of the order of 300 GeV or more could result in dynamical electroweak symmetry breaking by forming condensates through the exchange of a fundamental Higgs scalar doublet or triplet. These condensates are dynamically studied within the framework of the Schwinger- Dyson equation. With the electroweak symmetry broken by condensates, the fully worked-out model of EWRH in which there are two doublets and two triplets, one of which is composite and the others being the original fundamental scalar doublet and triplet could be suitable for recent LHC discovery of the 125 GeV scalar particle.

  9. Regular scalar collapse

    NASA Astrophysics Data System (ADS)

    Lasukov, V. V.

    2012-06-01

    It is shown that negative Scalars can claim to be the object referred to as black holes, therefore observation of black holes means observation of Scalars. In contrast to blackholes, negative Scalars contain no singularity inside. Negative Scalars can be observed from the effect of generation of ordinary matter by the Lemaître primordial atom.

  10. Revealing the interactions between pentagon-octagon-pentagon defect graphene and organic donor/acceptor molecules: a theoretical study.

    PubMed

    Li, Jie-Wei; Liu, Yu-Yu; Xie, Ling-Hai; Shang, Jing-Zhi; Qian, Yan; Yi, Ming-Dong; Yu, Ting; Huang, Wei

    2015-02-21

    Defect engineering and the non-covalent interaction strategy allow for dramatically tuning the optoelectronic features of graphene. Herein, we theoretically investigated the intrinsic mechanism of non-covalent interactions between pentagon-octagon-pentagon (5-8-5) defect graphene (DG) and absorbed molecules, tetrathiafulvalene (TTF), perfluoronaphthalene (FNa), tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), through geometry, distance, interaction energy, Mulliken charge distribution, terahertz frequency vibration, visualization of the interactions, charge density difference, electronic transition behaviour, band structure and density of state. All the calculations were performed using density functional theory including a dispersion correction (DFT-D). The calculated results indicate that the cyano- (CN) group (electron withdraw group) in TCNQ and F4TCNQ, rather than the F group, gain the electron from DG effectively and exhibit much stronger interactions via wavefunction overlap with DG, leading to a short non-covalent interaction distance, a large interaction energy and a red-shift of out-of-plane terahertz frequency vibration, changing the bands near the Fermi level and enhancing the infrared (IR) light absorption significantly. The enhancement of such IR absorbance offering a broader absorption (from 300 to 1200 nm) will benefit light harvesting in potential applications of solar energy conversion.

  11. Revealing the interactions between pentagon-octagon-pentagon defect graphene and organic donor/acceptor molecules: a theoretical study.

    PubMed

    Li, Jie-Wei; Liu, Yu-Yu; Xie, Ling-Hai; Shang, Jing-Zhi; Qian, Yan; Yi, Ming-Dong; Yu, Ting; Huang, Wei

    2015-02-21

    Defect engineering and the non-covalent interaction strategy allow for dramatically tuning the optoelectronic features of graphene. Herein, we theoretically investigated the intrinsic mechanism of non-covalent interactions between pentagon-octagon-pentagon (5-8-5) defect graphene (DG) and absorbed molecules, tetrathiafulvalene (TTF), perfluoronaphthalene (FNa), tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), through geometry, distance, interaction energy, Mulliken charge distribution, terahertz frequency vibration, visualization of the interactions, charge density difference, electronic transition behaviour, band structure and density of state. All the calculations were performed using density functional theory including a dispersion correction (DFT-D). The calculated results indicate that the cyano- (CN) group (electron withdraw group) in TCNQ and F4TCNQ, rather than the F group, gain the electron from DG effectively and exhibit much stronger interactions via wavefunction overlap with DG, leading to a short non-covalent interaction distance, a large interaction energy and a red-shift of out-of-plane terahertz frequency vibration, changing the bands near the Fermi level and enhancing the infrared (IR) light absorption significantly. The enhancement of such IR absorbance offering a broader absorption (from 300 to 1200 nm) will benefit light harvesting in potential applications of solar energy conversion. PMID:25559269

  12. Theoretical Prediction of Hydrogen Separation Performance of Two-Dimensional Carbon Network of Fused Pentagon.

    PubMed

    Zhu, Lei; Xue, Qingzhong; Li, Xiaofang; Jin, Yakang; Zheng, Haixia; Wu, Tiantian; Guo, Qikai

    2015-12-30

    Using the van-der-Waals-corrected density functional theory (DFT) and molecular dynamic (MD) simulations, we theoretically predict the H2 separation performance of a new two-dimensional sp(2) carbon allotropes-fused pentagon network. The DFT calculations demonstrate that the fused pentagon network with proper pore sizes presents a surmountable energy barrier (0.18 eV) for H2 molecule passing through. Furthermore, the fused pentagon network shows an exceptionally high selectivity for H2/gas (CO, CH4, CO2, N2, et al.) at 300 and 450 K. Besides, using MD simulations we demonstrate that the fused pentagon network exhibits a H2 permeance of 4 × 10(7) GPU at 450 K, which is much higher than the value (20 GPU) in the current industrial applications. With high selectivity and excellent permeability, the fused pentagon network should be an excellent candidate for H2 separation. PMID:26632974

  13. Origin of kinetic instability of fullerenes that violate the isolated pentagon rule.

    PubMed

    Aihara, Jun-ichi

    2015-03-26

    The isolated pentagon rule (IPR) holds without exceptions for neutral fullerene molecules. Unlike those in non-IPR fullerenes, 5/5 bonds (i.e., π-bonds shared by two pentagons) in many planar polycyclic π-systems are kinetically rather stable with large positive bond resonance energies (BREs), where BRE is a graph-theoretically defined index of kinetic stability. Geometric conditions were explored for designing planar polycyclic π-systems with unstable 5/5 bonds. We then found that the kinetic instability of non-IPR fullerenes stems from the coexistence of pentalene substructures and nearby disjoint pentagons. Proper arrangements of fused pentagons and disjoint pentagons make the 5/5 bonds highly reactive with large negative BREs. PMID:25746678

  14. Explicit one-loop corrections to the strong CP-violating phase in SU(2)/sub L/ x U(1)

    SciTech Connect

    Goffin, V.; Segre, G.; Weldon, H.A.

    1980-03-01

    In a CP-invariant Lagrangian the spontaneous symmetry breaking that generates the quark mass matrix m will induce CP violations into the strong interactions with strength theta/sub QFD/=arg Detm, where QFD refers to quantum flavor dynamics. Even if Detm is real in tree approximation, it will generally not be in higher order. We show that in any SU(2)/sub L/ x U(1) model the only one-loop corrections to theta/sub QFD/ come from Higgs particles. These are explicitly calculated in a six-quark model with permutation symmetry. We find theta/sub QFD/ approx. = 10/sup -10/(m/sub s//m/sub b/)(m/sub t//m/sub b/)/sup 2/ in one case and theta/sub QFD/ approx. = 10/sup -8/(m/sub c//m/sub t/) in a second case. Cabibbo angles and CP violation in the kaon system are also examined.

  15. Continuum behavior of lattice QED, discretized with one-sided lattice differences, in one-loop order

    SciTech Connect

    Sadooghi, N.; Rothe, H.J.

    1997-06-01

    A lattice action for QED is considered, where the derivatives in the Dirac operator are replaced by one-sided lattice differences. A systematic expansion in the lattice spacing of the one-loop contribution to the fermion self-energy, vacuum polarization tensor, and vertex function is carried out for an arbitrary choice of one-sided lattice differences. It is shown that only the vacuum polarization tensor possesses the correct continuum limit, while the fermion self-energy and vertex function receive noncovariant contributions. A lattice action, discretized with a fixed choice of one-sided lattice differences, therefore, does not define a renormalizable field theory. The noncovariant contributions can, however, be eliminated by averaging the expression over all possible choices of one-sided lattice differences. {copyright} {ital 1997} {ital The American Physical Society}

  16. Pentagone internalises glypicans to fine-tune multiple signalling pathways.

    PubMed

    Norman, Mark; Vuilleumier, Robin; Springhorn, Alexander; Gawlik, Jennifer; Pyrowolakis, George

    2016-01-01

    Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated. PMID:27269283

  17. The one-loop worldsheet S-matrix for the AdS n × S n × T 10-2 n superstring

    NASA Astrophysics Data System (ADS)

    Roiban, Radu; Sundin, Per; Tseytlin, Arkady; Wulff, Linus

    2014-08-01

    We compute the massive-sector worldsheet S-matrix for superstring theories in AdS n × S n × T 10-2 n (with n = 2 , 3 , 5) in the near BMN expansion up to one-loop order in inverse string tension. We show that, after taking into account the wave function renormalization, the one-loop S-matrix is UV finite. In an appropriate regularization scheme the S-matrix is consistent with the underlying symmetries of the superstring theory, i.e. for the n=3 ,5casesitcoincideswiththeoneimpliedbythelight-conegaugesymmetrieswiththe dressing phases determined from the crossing equations. For the n = 2 , 3 cases we observe that the massless modes decouple from the one-loop calculation of massive mode scattering, i.e. the 2 n-dimensional supercoset sigma model and the full 10-dimensional superstring happen to have the same massive one-loop S-matrix.

  18. golem95: A numerical program to calculate one-loop tensor integrals with up to six external legs

    NASA Astrophysics Data System (ADS)

    Binoth, T.; Guillet, J.-Ph.; Heinrich, G.; Pilon, E.; Reiter, T.

    2009-11-01

    We present a program for the numerical evaluation of form factors entering the calculation of one-loop amplitudes with up to six external legs. The program is written in Fortran95 and performs the reduction to a certain set of basis integrals numerically, using a formalism where inverse Gram determinants can be avoided. It can be used to calculate one-loop amplitudes with massless internal particles in a fast and numerically stable way. Catalogue identifier: AEEO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 50 105 No. of bytes in distributed program, including test data, etc.: 241 657 Distribution format: tar.gz Programming language: Fortran95 Computer: Any computer with a Fortran95 compiler Operating system: Linux, Unix RAM: RAM used per form factor is insignificant, even for a rank six six-point form factor Classification: 4.4, 11.1 External routines: Perl programming language (http://www.perl.com/) Nature of problem: Evaluation of one-loop multi-leg tensor integrals occurring in the calculation of next-to-leading order corrections to scattering amplitudes in elementary particle physics. Solution method: Tensor integrals are represented in terms of form factors and a set of basic building blocks ("basis integrals"). The reduction to the basis integrals is

  19. Constructing scalar-photon three point vertex in massless quenched scalar QED

    NASA Astrophysics Data System (ADS)

    Fernández-Rangel, L. Albino; Bashir, Adnan; Gutiérrez-Guerrero, L. X.; Concha-Sánchez, Y.

    2016-03-01

    Nonperturbative studies of Schwinger-Dyson equations require their infinite, coupled tower to be truncated in order to reduce them to a practically solvable set. In this connection, a physically acceptable Ansatz for the three point vertex is the most favorite choice. Scalar quantum electrodynamics (sQED) provides a simple and neat platform to address this problem. The most general form of the three point scalar-photon vertex can be expressed in terms of only two independent form factors, a longitudinal and a transverse one. Ball and Chiu have demonstrated that the longitudinal vertex is fixed by requiring the Ward-Fradkin-Green-Takahashi identity while the transverse vertex remains undetermined. In massless quenched sQED, we construct the transverse part of the nonperturbative scalar-photon vertex. This construction (i) ensures multiplicative renormalizability of the scalar propagator in keeping with the Landau-Khalatnikov-Fradkin transformations, (ii) has the same transformation properties as the bare vertex under charge conjugation, parity and time reversal, (iii) has no kinematic singularities and (iv) reproduces the one-loop asymptotic result in the weak coupling regime of the theory.

  20. Enhanced one-loop corrections to WIMP annihilation and their thermal relic density in the coannihilation region

    NASA Astrophysics Data System (ADS)

    Drees, Manuel; Gu, Jie

    2013-03-01

    We consider quantum corrections to coannihilation processes of weakly interacting massive particles (WIMPs) due to the exchange of light bosons in the initial state (“Sommerfeld corrections”). We work at the one-loop level, i.e. we assume that these corrections can be treated perturbatively. Coannihilation is important if there is at least one additional new particle with mass close to the lightest WIMP, which is a dark matter candidate. In this case the exchange of a (relatively light) boson in the initial state can change the identity of the annihilating particles. The corrections we are interested in factorize, as in the case of WIMP self-annihilation treated previously, but they can mix different tree-level amplitudes. Moreover, even small mass splittings between the external particles and those in the loop can change the relevant loop functions significantly. We find exact analytical expressions for these functions and illustrate the effects by considering the cases of wino- or Higgsino-like neutralinos as examples.

  1. Dynamic criticality far from equilibrium: One-loop flow of Burgers-Kardar-Parisi-Zhang systems with broken Galilean invariance

    NASA Astrophysics Data System (ADS)

    Strack, Philipp

    2015-03-01

    Burgers-Kardar-Parisi-Zhang (KPZ) scaling has recently (re-) surfaced in a variety of physical contexts, ranging from anharmonic chains to quantum systems such as open superfluids, in which a variety of random forces may be encountered and/or engineered. Motivated by these developments, we here provide a generalization of the KPZ universality class to situations with long-ranged temporal correlations in the noise, which purposefully break the Galilean invariance that is central to the conventional KPZ solution. We compute the phase diagram and critical exponents of the KPZ equation with 1 /f noise (KPZ1 /f) in spatial dimensions 1 ≤d <4 using the dynamic renormalization group with a frequency cutoff technique in a one-loop truncation. Distinct features of KPZ1 /f are (i) a generically scale-invariant, rough phase at high noise levels that violates fluctuation-dissipation relations and exhibits hyperthermal statistics even in d =1 , (ii) a fine-tuned roughening transition at which the flow fulfills an emergent thermal-like fluctuation-dissipation relation, that separates the rough phase from (iii) a massive phase in 1

  2. One-loop omega-potential of quantum fields with ellipsoid constant-energy surface dispersion law

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.; Shipulya, M. A.

    2011-10-01

    Rapidly convergent expansions of a one-loop contribution to the partition function of quantum fields with ellipsoid constant-energy surface dispersion law are derived. The omega-potential is naturally decomposed into three parts: the quasiclassical contribution, the contribution from the branch cut of the dispersion law, and the oscillating part. The low- and high-temperature expansions of the quasiclassical part are obtained. An explicit expression and a relation of the contribution from the cut with the Casimir term and vacuum energy are established. The oscillating part is represented in the form of the Chowla-Selberg expansion of the Epstein zeta function. Various resummations of this expansion are considered. The general procedure developed is then applied to two models: massless particles in a box both at zero and nonzero chemical potential, and electrons in a thin metal film. Rapidly convergent expansions of the partition function and average particle number are obtained for these models. In particular, the oscillations of the chemical potential of conduction electrons in graphene and a thin metal film due to a variation of size of the crystal are described.

  3. Dynamic criticality far from equilibrium: One-loop flow of Burgers-Kardar-Parisi-Zhang systems with broken Galilean invariance.

    PubMed

    Strack, Philipp

    2015-03-01

    Burgers-Kardar-Parisi-Zhang (KPZ) scaling has recently (re-) surfaced in a variety of physical contexts, ranging from anharmonic chains to quantum systems such as open superfluids, in which a variety of random forces may be encountered and/or engineered. Motivated by these developments, we here provide a generalization of the KPZ universality class to situations with long-ranged temporal correlations in the noise, which purposefully break the Galilean invariance that is central to the conventional KPZ solution. We compute the phase diagram and critical exponents of the KPZ equation with 1/f noise (KPZ1/f) in spatial dimensions 1≤d<4 using the dynamic renormalization group with a frequency cutoff technique in a one-loop truncation. Distinct features of KPZ1/f are (i) a generically scale-invariant, rough phase at high noise levels that violates fluctuation-dissipation relations and exhibits hyperthermal statistics even in d=1, (ii) a fine-tuned roughening transition at which the flow fulfills an emergent thermal-like fluctuation-dissipation relation, that separates the rough phase from (iii) a massive phase in 1

  4. Hexagon and pentagon identities for the Z sub 3 Potts model

    SciTech Connect

    Ryang, S. )

    1991-04-15

    Investigating the transformation properties of the conformal blocks in the {ital Z}{sub 3} Potts model we derive some braid matrices. From the obtained braid matrices we explicitly show how the hexagon and pentagon identities are satisfied.

  5. Pentagone internalises glypicans to fine-tune multiple signalling pathways

    PubMed Central

    Norman, Mark; Vuilleumier, Robin; Springhorn, Alexander; Gawlik, Jennifer; Pyrowolakis, George

    2016-01-01

    Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated. DOI: http://dx.doi.org/10.7554/eLife.13301.001 PMID:27269283

  6. One-loop divergences in non-Abelian supersymmetric theories regularized by BRST-invariant version of the higher derivative regularization

    NASA Astrophysics Data System (ADS)

    Aleshin, S. S.; Kazantsev, A. E.; Skoptsov, M. B.; Stepanyantz, K. V.

    2016-05-01

    We consider a general non-Abelian renormalizable {N} = 1 supersymmetric gauge theory, regularized by higher covariant derivatives without breaking the BRST invariance, and calculate one-loop divergences for a general form of higher derivative regulator and of the gauge fixing term. It is demonstrated that the momentum integrals giving the one-loop β-function are integrals of double total derivatives independently of a particular choice of the higher derivative term. Evaluating them we reproduce the well-known result for the one-loop β-function. Also we find that the three-point ghost vertices with a single line of the quantum gauge superfield are not renormalized in the considered approximation.

  7. Scalar Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Mottola, Emil

    2016-03-01

    General Relativity receives quantum corrections relevant at macroscopic distance scales and near event horizons. These arise from the conformal scalar degree of freedom in the extended effective field theory (EFT) of gravity generated by the trace anomaly of massless quantum fields in curved space. Linearized around flat space this quantum scalar degree of freedom combines with the conformal part of the metric and predicts the existence of scalar spin-0 ``breather'' propagating gravitational waves in addition to the transverse tensor spin-2 waves of classical General Relativity. Estimates of the expected strength of scalar gravitational radiation from compact astrophysical sources are given.

  8. Electroweak baryogenesis in a scalar-assisted vectorlike fermion model

    NASA Astrophysics Data System (ADS)

    Xiao, Ming-Lei; Yu, Jiang-Hao

    2016-07-01

    We extend the standard model to a scalar-assisted vectorlike fermion model to realize electroweak baryogenesis. The extended Cabibbo-Kobayashi-Maskawa matrix, due to the mixing among the vectorlike quark and the standard model quarks, provides additional sources of the C P violation. Together with the enhancement from a large vectorlike quark mass, a large enough baryon-to-photon ratio could be obtained. The strongly first-order phase transition could be realized via the potential barrier which separates the broken minimum and the symmetric minimum in the scalar potential. We investigate in detail the one loop temperature-dependent effective potential and perform a random parameter scan to study the allowed parameter region that satisfies the strongly first order phase transition criteria vc≥Tc. Several distinct patterns of phase transition are classified and discussed. Among these patterns, a large trilinear mass term between the Higgs boson and the scalar is preferred, for it controls the width of the potential barrier. Our results indicate large quartic scalar couplings and a moderate mixing angle between the Higgs boson and the new scalar. This parameter region could be further explored at the Run 2 LHC.

  9. Design of modified pentagonal patch antenna on defective ground for Wi-Max/WLAN application

    NASA Astrophysics Data System (ADS)

    Rawat, Sanyog; Sharma, K. K.

    2016-04-01

    This paper presents the design and performance of a modified pentagonal patch antenna with defective ground plane. A pentagonal slot is inserted in the pentagonal patch and slot loaded ground through optimized dimensions is used in the antenna to resonate it at dual frequency. The geometry operates at two resonant frequencies (2.5 GHz and 5.58 GHz) and offers impedance bandwidth of 864 MHz and 554 MHz in the two bands of interest. The proposed antenna covers the lower band (2.45 to 2.484/2.495 to 2.695 GHz) and upper band (5.15 to 5.825 GHz/5.25 to 5.85 GHz) allocated for Wi-Max and WLAN communication systems.

  10. Electron diffraction analysis of the pentagonal arrangement of grains found in CVD pure Ni films

    SciTech Connect

    Campbell, A.N.; Carr, M.J.; VanderSande, J.B.

    1986-01-01

    The structure of each crystal in the pentagon is fcc, as verified by diffraction patterns from individual grains. It is suggested that the large pentagonal regions observed were nucleated by small decahedral clusters of Ni atoms during the early stages of the deposition. However, for grains as large as those shown the body centered orthorhombic structure is not stable; at some point during the growth process the crystal structure reverted to the energetically preferred fcc. The relative orientation between the individual crystals, having been established by the decahedral nucleus, was preserved during growth. The 7.5/sup 0/ mismatch was taken up evenly around the pentagon by the formation of dislocations and/or secondary twins at the boundaries.

  11. Enhancing immunomodulation on innate immunity by shape transition among RNA triangle, square and pentagon nanovehicles

    PubMed Central

    Khisamutdinov, Emil F.; Li, Hui; Jasinski, Daniel L.; Chen, Jiao; Fu, Jian; Guo, Peixuan

    2014-01-01

    Modulation of immune response is important in cancer immunotherapy, vaccine adjuvant development and inflammatory or immune disease therapy. Here we report the development of new immunomodulators via control of shape transition among RNA triangle, square and pentagon. Changing one RNA strand in polygons automatically induced the stretching of the interior angle from 60° to 90° or 108°, resulting in self-assembly of elegant RNA triangles, squares and pentagons. When immunological adjuvants were incorporated, their immunomodulation effect for cytokine TNF-α and IL-6 induction was greatly enhanced in vitro and in animals up to 100-fold, while RNA polygon controls induced unnoticeable effect. The RNA nanoparticles were delivered to macrophages specifically. The degree of immunostimulation greatly depended on the size, shape and number of the payload per nanoparticles. Stronger immune response was observed when the number of adjuvants per polygon was increased, demonstrating the advantage of shape transition from triangle to pentagon. PMID:25092921

  12. Time transients in the quantum corrected Newtonian potential induced by a massless nonminimally coupled scalar field

    SciTech Connect

    Marunovic, Anja; Prokopec, Tomislav

    2011-05-15

    We calculate the one-loop graviton vacuum polarization induced by a massless, nonminimally coupled scalar field on Minkowski background. We make use of the Schwinger-Keldysh formalism, which allows us to study time dependent phenomena. As an application we compute the leading quantum correction to the Newtonian potential of a point particle. The novel aspect of the calculation is the use of the Schwinger-Keldysh formalism, within which we calculate the time transients induced by switching on the graviton-scalar coupling.

  13. Inflationary universe from higher derivative quantum gravity coupled with scalar electrodynamics

    NASA Astrophysics Data System (ADS)

    Myrzakulov, R.; Odintsov, S. D.; Sebastiani, L.

    2016-06-01

    We study inflation for a quantum scalar electrodynamics model in curved space-time and for higher-derivative quantum gravity (QG) coupled with scalar electrodynamics. The corresponding renormalization-group (RG) improved potential is evaluated for both theories in Jordan frame where non-minimal scalar-gravitational coupling sector is explicitly kept. The role of one-loop quantum corrections is investigated by showing how these corrections enter in the expressions for the slow-roll parameters, the spectral index and the tensor-to-scalar ratio and how they influence the bound of the Hubble parameter at the beginning of the primordial acceleration. We demonstrate that the viable inflation maybe successfully realized, so that it turns out to be consistent with last Planck and BICEP2/Keck Array data.

  14. Comparison of aerodynamic characteristics of pentagonal and hexagonal shaped bridge decks

    NASA Astrophysics Data System (ADS)

    Haque, Md. Naimul; Katsuchi, Hiroshi; Yamada, Hitoshi; Nishio, Mayuko

    2016-07-01

    Aerodynamics of the long-span bridge deck should be well understood for an efficient design of the bridge system. For practical bridges various deck shapes are being recommended and adopted, yet not all of their aerodynamic behaviors are well interpreted. In the present study, a numerical investigation was carried out to explore the aerodynamic characteristics of pentagonal and hexagonal shaped bridge decks. A relative comparison of steady state aerodynamic responses was made and the flow field was critically analyzed for better understanding the aerodynamic responses. It was found that the hexagonal shaped bridge deck has better aerodynamic characteristics as compared to the pentagonal shaped bridge deck.

  15. Scalar Contribution to the Graviton Self-Energy During Inflation

    SciTech Connect

    Park, Sohyun

    2012-01-01

    We use dimensional regularization to evaluate the one loop contribution to the graviton self-energy from a massless, minimally coupled scalar on a locally de Sitter background. For noncoincident points our result agrees with the stress tensor correlators obtained recently by Perez-Nadal, Roura and Verdaguer. We absorb the ultraviolet divergences using the R2 and C2 counterterms first derived by ’t Hooft and Veltman, and we take the D = 4 limit of the finite remainder. The renormalized result is expressed as the sum of two transverse, 4th order differential operators acting on nonlocal, de Sitter invariant structure functions. In this form it can be used to quantum-correct the linearized Einstein equations so that one can study how the inflationary production of infrared scalars affects the propagation of dynamical gravitons and the force of gravity. We have seen that they have no effect on the propagation of dynamical gravitons. Our computation motivates a conjecture for the first correction to the vacuum state wave functional of gravitons. We comment as well on performing the same analysis for the more interesting contribution from inflationary gravitons, and on inferring one loop corrections to the force of gravity.

  16. Factorization for radiative heavy quarkonium decays into scalar Glueball

    NASA Astrophysics Data System (ADS)

    Zhu, Ruilin

    2015-09-01

    We establish the factorization formula for scalar Glueball production through radiative decays of vector states of heavy quarkonia, e.g. J/ ψ, ψ(2 S) and Υ( nS), where the Glueball mass is much less than the parent heavy quarkonium mass. The factorization is demonstrated explicitly at one-loop level through the next-to-leading order (NLO) corrections to the hard kernel, the non-relativistic QCD (NRQCD) long-distance matrix elements (LDMEs) of the heavy quarkonium, and the light-cone distribution amplitude (LCDA) of scalar Glueball. The factorization provides a comprehensive theoretical approach to investigate Glueball production in the radiative decays of vector states of heavy quarkonia and determine the physic nature of Glueball. We discuss the scale evolution equation of LCDA for scalar Glueball. In the end, we extract the value of the decay constant of Scalar Glueball from Lattice QCD calculation and analyze the mixing effect among f 0(1370), f 0(1500) and f 0(1710).

  17. Maximum aromaticity or maximum pentagon separation; which is the origin behind the stability of endohedral metallofullerenes?

    PubMed

    Rodríguez-Fortea, Antonio; Poblet, Josep M

    2014-01-01

    Two different interpretations have been recently proposed to rationalize the stabilization of some hosting cages in endohedral metallofullerenes as a consequence of the larger localization of the negative charge on pentagonal rather than on hexagonal faces. We try to figure out the physical origin that mainly governs the stability of charged fullerenes; is it aromaticity or electrostatics?

  18. Maximum aromaticity or maximum pentagon separation; which is the origin behind the stability of endohedral metallofullerenes?

    PubMed

    Rodríguez-Fortea, Antonio; Poblet, Josep M

    2014-01-01

    Two different interpretations have been recently proposed to rationalize the stabilization of some hosting cages in endohedral metallofullerenes as a consequence of the larger localization of the negative charge on pentagonal rather than on hexagonal faces. We try to figure out the physical origin that mainly governs the stability of charged fullerenes; is it aromaticity or electrostatics? PMID:25467947

  19. How does particle shape affect the near jamming properties of granular materials? Pentagons vs. disks

    NASA Astrophysics Data System (ADS)

    Zhao, Yiqiu; Bares, Jonathan; Behringer, Bob

    Understanding the role of particle shape in system-scale properties is a fundamental challenge in granular physics. We investigated the difference between the response of systems made of pentagons vs. more traditional disks. We performed isotropic compression experiments on 2D photoelastic pentagons and disks near the jamming transition. These experiments show qualitative and quantitative differences in the macroscopic responses of the two systems, such as shifts in the packing fraction at jamming onset and differences in the contact number evolution. Some of these differences are due to a reduction of packing order and the appearance of side-side contacts for the pentatons. We also examined the stress relaxation and dynamical heterogeneity of pentagon particles by performing cyclic compression to allow the system explore phase diagram. We contrast disk and pentagon evolution using four-point-susceptibility and G2 techniques. Work supported by NSF-DMR1206351, DMS1248071, NASA NNX15AD38G, and the W.M. Keck Foundation.

  20. From Pentagon to Triangle: A Cross-Cultural Investigation of an Implicit Theory of Giftedness.

    ERIC Educational Resources Information Center

    Zhang, Li-fang; Hui, Sammy King-fai

    2002-01-01

    This study examined use of Sternberg and Zhang's (1995) pentagonal implicit theory of giftedness by 189 preservice teachers in China. In making judgments about giftedness, study participants considered three of the models' five criteria: excellence, productivity, and value (but not rarity and demonstrability). Results are compared to similar…

  1. The trace anomaly and massless scalar degrees of freedom

    SciTech Connect

    Gianotti, Maurizio; Mottola, Emil

    2008-01-01

    The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, we compute the full one-loop triangle amplitude of the fermionic stress tensor with two current vertices, {open_square}T{sup {mu}{nu}}J{sup {alpha}}J{sup {beta}}, and exhibit the scalar pole in this amplitude associated with the trace anomaly, in the limit of zero electron mass m{yields}0. To emphasize the infrared aspect of the anomaly, we use a dispersive approach and show that this amplitude and the existence of the massless scalar pole is determined completely by its ultraviolet finite terms, together with the requirements of Poincare invariance of the vacuum, Bose symmetry under interchange of J{sup {alpha}} and J{sup {beta}}, and vector current and stress-tensor conservation. We derive a sum rule for the appropriate positive spectral function corresponding to the discontinuity of the triangle amplitude, showing that it becomes proportional to {delta}(k{sup 2}) and therefore contains a massless scalar intermediate state in the conformal limit of zero electron mass. The effective action corresponding to the trace of the triangle amplitude can be expressed in local form by the introduction of two scalar auxiliary fields which satisfy massless wave equations. These massless scalar degrees of freedom couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects.

  2. Regarding the scalar mesons

    SciTech Connect

    Liu Yunhu; Shao Jianxin; Wang Xiaogang; Zhang Ziying; Li Demin

    2008-02-01

    Based on the main assumption that the D{sub sJ}(2860) belongs to the 2{sup 3}P{sub 0} qq multiplet, the masses of the scalar meson nonet are estimated in the framework of the relativistic independent quark model, Regge phenomenology, and meson-meson mixing. We suggest that the a{sub 0}(1005), K{sub 0}*(1062), f{sub 0}(1103), and f{sub 0}(564) constitute the ground scalar meson nonet; it is supposed that these states would likely correspond to the observed states a{sub 0}(980), {kappa}(900), f{sub 0}(980), and f{sub 0}(600)/{sigma}, respectively. Also a{sub 0}(1516), K{sub 0}*(1669), f{sub 0}(1788), and f{sub 0}(1284) constitute the first radial scalar meson nonet, it is supposed that these states would likely correspond to the observed states a{sub 0}(1450), K{sub 0}*(1430), f{sub 0}(1710), and f{sub 0}(1370), respectively. The scalar state f{sub 0}(1500) may be a good candidate for the ground scalar glueball. The agreement between the present findings and those given by other different approaches is satisfactory.

  3. SFOLD — A program package for calculating two-body sfermion decays at full one-loop level in the MSSM

    NASA Astrophysics Data System (ADS)

    Hluchá, H.; Eberl, H.; Frisch, W.

    2012-10-01

    SFOLD (Sfermion Full One-Loop Decays) is a Fortran program package for calculating all sfermion two-body decay widths and the corresponding branching ratios at full one-loop level within the MSSM. The package adopts the SUSY Parameter Analysis convention and supports the SUSY Les Houches Accord input and output format. With the SFOLD package we found non-negligible electroweak corrections in bosonic decays of b˜,t˜ and τ˜. Program summaryProgram title: SFOLD Catalogue identifier: AEMZ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMZ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 263346 No. of bytes in distributed program, including test data, etc.: 1481697 Distribution format: tar.gz Programming language: Fortran 77. Computer: Workstation, PC. Operating system: Linux. RAM: approx. 500 Mbytes Classification: 11.1. External routines: LoopTools 2.6 (http://www.feynarts.de/looptools/), SLHALib 2.2 (http://www.feynarts.de/slha/) Nature of problem: If the MSSM is realized in nature, LHC will produce supersymmetric particles copiously. The best environment for a precise determination of the model parameters would be a high energy e+e- linear collider. Experimental accuracies are expected at the per-cent down to the per-mill level. These must be matched from the theoretical side. Therefore loop calculations are mandatory. Solution method: This program package calculates all sfermion two-body decay widths and the corresponding branching ratios at full one-loop level within the MSSM. The renormalization is done in the DR¯ scheme following the SUSY Parameter Analysis convention. The program supports the SUSY Les Houches Accord input and output format. Running time: The test provided just takes a few seconds to run.

  4. Constraint on R-parity violating MSSM at the one-loop level from CP-odd N-N interaction

    SciTech Connect

    Yamanaka, Nodoka; Sato, Toru; Kubota, Takahiro

    2011-10-21

    Minimal supersymmetric standard model with R-parity violation (RPVMSSM) contributes to the P-, CP-odd four-quark interaction. The P-, CP-odd four-quark interaction is constrained by the new {sup 199}Hg EDM experimental data. It is then possible to constrain R-parity violating (RPV) couplings from the {sup 199}Hg EDM data. In this talk, we analyze the RPV contribution to the P-, CP-odd four-quark interaction at the one-loop level to give constraints on RPV parameters.

  5. One-loop corrections to the perturbative unitarity bounds in the CP-conserving two-Higgs doublet model with a softly broken {mathbb{Z}}_2 symmetry

    NASA Astrophysics Data System (ADS)

    Grinstein, Benjamín; Murphy, Christopher W.; Uttayarat, Patipan

    2016-06-01

    We compute all of the one-loop corrections that are enhanced, O( λ i λ j /16 π 2), in the limit s ≫ | λ i | v 2 ≫ M W 2 , s ≫ m 12 2 to all the 2 → 2 longitudinal vector boson and Higgs boson scattering amplitudes in the CP -conserving two-Higgs doublet model with a softly broken {mathbb{Z}}_2 symmetry. In the two simplified scenarios we study, the typical bound we find is | λ i ( s)| ⪷ 4.

  6. Radiative corrections to the Higgs boson couplings in the model with an additional real singlet scalar field

    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.

  7. Renormalization group equation study of the scalar sector of the minimal B-L extension of the standard model

    SciTech Connect

    Basso, Lorenzo; Moretti, Stefano; Pruna, Giovanni Marco

    2010-09-01

    We present the complete set of renormalization group equations at one loop for the nonexotic minimal U(1) extension of the standard model (SM). It includes all models that are anomaly-free with the SM fermion content augmented by one right-handed neutrino per generation. We then pursue the numerical study of the pure B-L model, deriving the triviality and vacuum stability bounds on an enlarged scalar sector comprising one additional Higgs singlet field with respect to the SM.

  8. Electronic and transport properties in circular graphene structures with a pentagonal disclination

    PubMed Central

    2013-01-01

    We investigate the electronic and transport properties of circular graphene structures (quantum dots) that include a pentagonal defect. In our calculations, we employ a tight-binding model determining total and local density of states, transmission function and participation number. For the closed structure, we observe that the effect of the defect is concentrated mainly on energies near to zero, which is characteristic of edge states in graphene. The density of states and transmission functions for small energies show several peaks associated with the presence of quasi-bound states generated by the defect and localized edge states produced by both the circular boundaries of the finite lattice and induced by the presence of the pentagonal defect. These results have been checked by calculating the participation number, which is obtained from the eigenstates. We observe changes in the available quasi-bound states due to the defect and the creation of new peaks in the transmission function. PMID:23718555

  9. Multi-disclination configurations in pentagonal microcrystals and two-dimensional carbon structures

    NASA Astrophysics Data System (ADS)

    Yasnikov, I. S.; Kolesnikova, A. L.; Romanov, A. E.

    2016-06-01

    A mechanism of decrease in the elastic (latent) energy of a solid containing disclination defects by introducing multi-disclination configurations of opposite sign has been considered. The relation of the proposed model with relaxation modifications of microcrystals with pentagonal symmetry, as well as with the structure of two-dimensional carbon films, has been discussed. An approach to the prediction of new carbon structures inherently containing multi-disclination configurations with screening has been demonstrated.

  10. Evolution of Pentagonal Nano- and Micro-Objects in Temperature Fields

    NASA Astrophysics Data System (ADS)

    Dorogov, M. V.; Vikarchuk, A. A.; Romanov, A. E.

    2015-10-01

    The effect of temperature and annealing atmosphere on the structure and morphology of small icosahedral copper particles and filamentary pentagonal crystals has been investigated. Particles and filamentary crystals were obtained by electrodeposition of metal, and their structure and morphology were investigated by electron microscopy and x-ray diffraction. It has been shown that during annealing, whiskers are formed on the surface of the particles together with porous and "flake" structures, and cavities are formed inside them.

  11. Structure of force networks in tapped particulate systems of disks and pentagons. I. Clusters and loops

    NASA Astrophysics Data System (ADS)

    Pugnaloni, Luis A.; Carlevaro, C. Manuel; Kramár, M.; Mischaikow, K.; Kondic, L.

    2016-06-01

    The force network of a granular assembly, defined by the contact network and the corresponding contact forces, carries valuable information about the state of the packing. Simple analysis of these networks based on the distribution of force strengths is rather insensitive to the changes in preparation protocols or to the types of particles. In this and the companion paper [Kondic et al., Phys. Rev. E 93, 062903 (2016), 10.1103/PhysRevE.93.062903], we consider two-dimensional simulations of tapped systems built from frictional disks and pentagons, and study the structure of the force networks of granular packings by considering network's topology as force thresholds are varied. We show that the number of clusters and loops observed in the force networks as a function of the force threshold are markedly different for disks and pentagons if the tangential contact forces are considered, whereas they are surprisingly similar for the network defined by the normal forces. In particular, the results indicate that, overall, the force network is more heterogeneous for disks than for pentagons. Such differences in network properties are expected to lead to different macroscale response of the considered systems, despite the fact that averaged measures (such as force probability density function) do not show any obvious differences. Additionally, we show that the states obtained by tapping with different intensities that display similar packing fraction are difficult to distinguish based on simple topological invariants.

  12. Structure of force networks in tapped particulate systems of disks and pentagons. I. Clusters and loops.

    PubMed

    Pugnaloni, Luis A; Carlevaro, C Manuel; Kramár, M; Mischaikow, K; Kondic, L

    2016-06-01

    The force network of a granular assembly, defined by the contact network and the corresponding contact forces, carries valuable information about the state of the packing. Simple analysis of these networks based on the distribution of force strengths is rather insensitive to the changes in preparation protocols or to the types of particles. In this and the companion paper [Kondic et al., Phys. Rev. E 93, 062903 (2016)10.1103/PhysRevE.93.062903], we consider two-dimensional simulations of tapped systems built from frictional disks and pentagons, and study the structure of the force networks of granular packings by considering network's topology as force thresholds are varied. We show that the number of clusters and loops observed in the force networks as a function of the force threshold are markedly different for disks and pentagons if the tangential contact forces are considered, whereas they are surprisingly similar for the network defined by the normal forces. In particular, the results indicate that, overall, the force network is more heterogeneous for disks than for pentagons. Such differences in network properties are expected to lead to different macroscale response of the considered systems, despite the fact that averaged measures (such as force probability density function) do not show any obvious differences. Additionally, we show that the states obtained by tapping with different intensities that display similar packing fraction are difficult to distinguish based on simple topological invariants. PMID:27415342

  13. Structure of force networks in tapped particulate systems of disks and pentagons. I. Clusters and loops.

    PubMed

    Pugnaloni, Luis A; Carlevaro, C Manuel; Kramár, M; Mischaikow, K; Kondic, L

    2016-06-01

    The force network of a granular assembly, defined by the contact network and the corresponding contact forces, carries valuable information about the state of the packing. Simple analysis of these networks based on the distribution of force strengths is rather insensitive to the changes in preparation protocols or to the types of particles. In this and the companion paper [Kondic et al., Phys. Rev. E 93, 062903 (2016)10.1103/PhysRevE.93.062903], we consider two-dimensional simulations of tapped systems built from frictional disks and pentagons, and study the structure of the force networks of granular packings by considering network's topology as force thresholds are varied. We show that the number of clusters and loops observed in the force networks as a function of the force threshold are markedly different for disks and pentagons if the tangential contact forces are considered, whereas they are surprisingly similar for the network defined by the normal forces. In particular, the results indicate that, overall, the force network is more heterogeneous for disks than for pentagons. Such differences in network properties are expected to lead to different macroscale response of the considered systems, despite the fact that averaged measures (such as force probability density function) do not show any obvious differences. Additionally, we show that the states obtained by tapping with different intensities that display similar packing fraction are difficult to distinguish based on simple topological invariants.

  14. Pragmatic Aspects of Scalar Modifiers

    ERIC Educational Resources Information Center

    Sawada, Osamu

    2010-01-01

    This dissertation investigates the pragmatic aspects of scalar modifiers from the standpoint of the interface between semantics and pragmatics, focusing on (i) the (non) parallelism between the truth-conditional scalar modifiers and the non-truth-conditional scalar modifiers, (ii) the compositionality and dimensionality of non-truth-conditional…

  15. Feynman rules for the rational part of the standard model one-loop amplitudes in the 't Hooft-Veltman γ 5 scheme

    NASA Astrophysics Data System (ADS)

    Shao, Hua-Sheng; Zhang, Yu-Jie; Chao, Kuang-Ta

    2011-09-01

    We study Feynman rules for the rational part R of the Standard Model amplitudes at one-loop level in the 't Hooft-Veltman γ 5 scheme. Comparing our results for quantum chromodynamics and electroweak 1-loop amplitudes with that obtained based on the Kreimer-Korner-Schilcher (KKS) γ 5 scheme, we find the latter result can be recovered when our γ 5 scheme becomes identical (by setting g5 s = 1 in our expressions) with the KKS scheme. As an independent check, we also calculate Feynman rules obtained in the KKS scheme, finding our results in complete agreement with formulae presented in the literature. Our results, which are studied in two different γ 5 schemes, may be useful for clarifying the γ 5 problem in dimensional regularization. They are helpful to eliminate or find ambiguities arising from different dimensional regularization schemes.

  16. Two Higgs doublet models augmented by a scalar colour octet

    NASA Astrophysics Data System (ADS)

    Cheng, Li; Valencia, German

    2016-09-01

    The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet models (2HDM). In this paper we extend those studies to include constraints on the one loop couplings of the Higgs to gluons and photons. These couplings are particularly sensitive to the existence of new coloured particles that are hard to detect otherwise and we use them to constrain a 2HDM augmented with a colour-octet scalar, a possibility motivated by minimal flavour violation. We first study theoretical constraints on this model and then compare them with LHC measurements.

  17. Conformal scalar field wormholes

    NASA Technical Reports Server (NTRS)

    Halliwell, Jonathan J.; Laflamme, Raymond

    1989-01-01

    The Euclidian Einstein equations with a cosmological constant and a conformally coupled scalar field are solved, taking the metric to be of the Robertson-Walker type. In the case Lambda = 0, solutions are found which represent a wormhole connecting two asymptotically flat Euclidian regions. In the case Lambda greater than 0, the solutions represent tunneling from a small Tolman-like universe to a large Robertson-Walker universe.

  18. Scalar and Pseudoscalar Glueballs

    NASA Astrophysics Data System (ADS)

    Cheng, Hai-Yang

    We employ two simple and robust results to constrain the mixing matrix of the isosinglet scalar mesons f0(1710), f0(1500), f0(1370): one is the approximate SU(3) symmetry empirically observed in the scalar sector above 1 GeV and confirmed by lattice QCD, and the other is the scalar glueball mass at 1710 MeV in the quenched approximation. In the SU(3) symmetry limit, f0(1500) becomes a pure SU(3) octet and is degenerate with a0(1450), while f0(1370) is mainly an SU(3) singlet with a slight mixing with the scalar glueball which is the primary component of f0(1710). These features remain essentially unchanged even when SU(3) breaking is taken into account. The observed enhancement of ωf0(1710) production over ɸf0(1710) in hadronic J/ψ decays and the copious f0(1710) production in radiative J/ψ decays lend further support to the prominent glueball nature of f0(1710). We deduce the mass of the pseudoscalar glueball G from an η-η‧-G mixing formalism based on the anomalous Ward identity for transition matrix elements. With the inputs from the recent KLOE experiment, we find a solution for the pseudoscalar glueball mass around (1.4±0.1) GeV, which is fairly insensitive to a range of inputs with or without Okubo-Zweig-Iizuka-rule violating effects. This affirms that η(1405), having a large production rate in the radiative J/ψ decay and not seen in γγ reactions, is indeed a leading candidate for the pseudoscalar glueball. It is much lower than the results from quenched lattice QCD (> 2.0 GeV) due to the dynamic fermion effect. It is thus urgent to have a full QCD lattice calculation of pseudoscalar glueball masses.

  19. Imploding scalar fields

    SciTech Connect

    Roberts, M.D.

    1996-09-01

    Static spherically symmetric uncoupled scalar space{endash}times have no event horizon and a divergent Kretschmann singularity at the origin of the coordinates. The singularity is always present so that nonstatic solutions have been sought to see if the singularities can develop from an initially singular free space{endash}time. In flat space{endash}time the Klein{endash}Gordon equation {D`Alembertian}{var_phi}=0 has the nonstatic spherically symmetric solution {var_phi}={sigma}({ital v})/{ital r}, where {sigma}({ital v}) is a once differentiable function of the null coordinate {ital v}. In particular, the function {sigma}({ital v}) can be taken to be initially zero and then grow, thus producing a singularity in the scalar field. A similar situation occurs when the scalar field is coupled to gravity via Einstein{close_quote}s equations; the solution also develops a divergent Kretschmann invariant singularity, but it has no overall energy. To overcome this, Bekenstein{close_quote}s theorems are applied to give two corresponding conformally coupled solutions. One of these has positive ADM mass and has the following properties: (i) it develops a Kretschmann invariant singularity, (ii) it has no event horizon, (iii) it has a well-defined source, (iv) it has well-defined junction condition to Minkowski space{endash}time, and (v) it is asymptotically flat with positive overall energy. This paper presents this solution and several other nonstatic scalar solutions. The properties of these solutions which are studied are limited to the following three: (i) whether the solution can be joined to Minkowski space{endash}time, (ii) whether the solution is asymptotically flat, (iii) and, if so, what the solutions{close_quote} Bondi and ADM masses are. {copyright} {ital 1996 American Institute of Physics.}

  20. Scalar multi-wormholes

    NASA Astrophysics Data System (ADS)

    Egorov, A. I.; Kashargin, P. E.; Sushkov, Sergey V.

    2016-09-01

    In 1921 Bach and Weyl derived the method of superposition to construct new axially symmetric vacuum solutions of general relativity. In this paper we extend the Bach–Weyl approach to non-vacuum configurations with massless scalar fields. Considering a phantom scalar field with the negative kinetic energy, we construct a multi-wormhole solution describing an axially symmetric superposition of N wormholes. The solution found is static, everywhere regular and has no event horizons. These features drastically tell the multi-wormhole configuration from other axially symmetric vacuum solutions which inevitably contain gravitationally inert singular structures, such as ‘struts’ and ‘membranes’, that keep the two bodies apart making a stable configuration. However, the multi-wormholes are static without any singular struts. Instead, the stationarity of the multi-wormhole configuration is provided by the phantom scalar field with the negative kinetic energy. Anther unusual property is that the multi-wormhole spacetime has a complicated topological structure. Namely, in the spacetime there exist 2 N asymptotically flat regions connected by throats.

  1. Scalar multi-wormholes

    NASA Astrophysics Data System (ADS)

    Egorov, A. I.; Kashargin, P. E.; Sushkov, Sergey V.

    2016-09-01

    In 1921 Bach and Weyl derived the method of superposition to construct new axially symmetric vacuum solutions of general relativity. In this paper we extend the Bach-Weyl approach to non-vacuum configurations with massless scalar fields. Considering a phantom scalar field with the negative kinetic energy, we construct a multi-wormhole solution describing an axially symmetric superposition of N wormholes. The solution found is static, everywhere regular and has no event horizons. These features drastically tell the multi-wormhole configuration from other axially symmetric vacuum solutions which inevitably contain gravitationally inert singular structures, such as ‘struts’ and ‘membranes’, that keep the two bodies apart making a stable configuration. However, the multi-wormholes are static without any singular struts. Instead, the stationarity of the multi-wormhole configuration is provided by the phantom scalar field with the negative kinetic energy. Anther unusual property is that the multi-wormhole spacetime has a complicated topological structure. Namely, in the spacetime there exist 2 N asymptotically flat regions connected by throats.

  2. Triangle and concave pentagon electrodes for an improved broadband frequency response of stripline beam position monitors

    NASA Astrophysics Data System (ADS)

    Shobuda, Yoshihiro; Chin, Yong Ho; Takata, Koji; Toyama, Takeshi; Nakamura, Keigo

    2016-02-01

    The frequency domain performance of a stripline beam position monitor depends largely on the longitudinal shape of its electrode. Some shapes other than a conventional rectangle have been proposed and tested. To attain a good impedance matching along the electrode, they need to be precisely bent down toward their downstream in proportion to their width. This is a considerable task, and a failure to comply with it will result in a large distortion of the frequency-domain transfer function from the ideal one due to unwanted signal reflections. In this report, we first propose a triangle electrode for easy fabrication and setup: it only requires that a triangularly cut flat electrode will be placed in a chamber while being obliquely inclined toward the downstream port. Theoretical and simulation results show that the simple triangle electrode has a remarkably flatter frequency response than the rectangle one. The frequency response, in particular at high frequencies, can be further improved by attaching an "apron" plate, perpendicular to the upstream edge of the electrode. The overshooting of the frequency response at low frequency can be eliminated by replacing the straight sidelines of the triangle by three-point polylines (with a result that the triangle is transformed to a concave pentagon). The concave pentagon electrode needs to be bent only once at the middle point of the polylines for a good impedance matching and thus its fabrication and setup remain to be easy. Rf measurements for the various electrode shapes have been carried out. We found that the concave pentagon electrode achieves a wide and flat frequency response up to about 4 GHz for the J-PARC Main Ring (MR).

  3. Regional significance of Mississippian rocks at Pentagon Mountain, Lewis and Clark Range, northwestern Montana

    SciTech Connect

    Nichols, K.M.

    1985-05-01

    Pentagon Mountain exposes one of the best of the few sections of Mississippian rocks in the Lewis and Clark Range of northwestern Montana. This section consists of 225 m (738 ft) of marine carbonate rocks from which conodonts, ranging in age from earliest Osagean to early Meramecian, have been identified. Its stratigraphic base is well exposed, but the top has been eroded. Five units are recognized in this sequence, in ascending order: (1) phosphatized coarsely crinoidal and spiculitic wackestone, (2) dolomitic lime mudstone or wackestone, thinly interbedded with spiculitic biogenic chert, (3) partly dolomitized lime bioclastic wackestone showing much pressure-solution compaction, (4) partly dolomitized lime bioclastic packstone or wackestone, also showing much pressure-solution compaction, and (5) dolomitic mudstone. The Mississippian sequence at Pentagon Mountain can be readily correlated lithologically, across the Lewis thrust system with Mississippian rocks that crop out to the east in the Sawtooth Range. This implies either that Mississippian units were originally widespread or that the magnitude of thrusting between the Mississippian rocks in the Lewis and Clark Range and those in the Sawtooth Range was insignificant. However, Mississippian rocks at Pentagon Mountain exhibit extreme pressure-solution compaction, which suggests greater stratigraphic or structural burial of these rocks than their Mississippian counterparts in the Sawtooth Range. Secondary dolomite is pervasive in the lower part of the Mississippian section in the Lewis and Clark Range, and spectacular solution breccias locally disrupt the base of the section. These breccias and the adjacent dolomite are probably related, as both are thought to result from the passage of fluids through these rocks during Laramide uplift and/or post Laramide erosion and extension.

  4. Geometric scalar theory of gravity

    SciTech Connect

    Novello, M.; Bittencourt, E.; Goulart, E.; Salim, J.M.; Toniato, J.D.; Moschella, U. E-mail: eduhsb@cbpf.br E-mail: egoulart@cbpf.br E-mail: toniato@cbpf.br

    2013-06-01

    We present a geometric scalar theory of gravity. Our proposal will be described using the ''background field method'' introduced by Gupta, Feynman, Deser and others as a field theory formulation of general relativity. We analyze previous criticisms against scalar gravity and show how the present proposal avoids these difficulties. This concerns not only the theoretical complaints but also those related to observations. In particular, we show that the widespread belief of the conjecture that the source of scalar gravity must be the trace of the energy-momentum tensor — which is one of the main difficulties to couple gravity with electromagnetic phenomenon in previous models — does not apply to our geometric scalar theory. From the very beginning this is not a special relativistic scalar gravity. The adjective ''geometric'' pinpoints its similarity with general relativity: this is a metric theory of gravity. Some consequences of this new scalar theory are explored.

  5. Multi-disclinational description of pentagonal particles with subsurface layer free of twin boundaries

    NASA Astrophysics Data System (ADS)

    Yasnikov, I. S.; Kolesnikova, A. L.; Romanov, A. E.

    2015-09-01

    We present the results on the modelling of structural changes in pentagonal small particles (PSPs) during their growth. We prove that after a certain critical size it becomes energetically favourable for a PSP to form a subsurface layer free of twin boundaries (TBs), which are only typical structural elements for smaller size PSPs. In this layer, the low-angle dislocation boundaries (DBs) are formed. Our calculations of the energy stored in the transformed PSP are based on the disclination model of a PSP, in which the TB junctions, as well as TB-DB junctions are treated as wedge disclinations.

  6. Ag microtubes with novel pentagon pores templated by fivefold symmetric Cu microrods

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Teng, Fei; Zhang, Tongyu; Kan, Yandong; Yang, Liming; Gu, Wenhao; Liu, Zailun; Liu, Zhe; Zhang, An; Teng, Yiran

    2016-10-01

    In this work, we report a green, simple and fast method to fabricate novel Cu@Ag core@shell and Ag microstructures. According to galvanic replacement, the novel pentagon-shaped pores of Ag can form from the shape memory effect of fivefold symmetric Cu template. Additionally, the Ag and Cu@Ag crystals with different microstructures can be controlled by changing the complexing agent, solvent, as well as the ion concentration and source of silver. This work suggests that a shape memory of template can be used for micro/nanostructure control.

  7. Unveiling the pentagonal nature of perfectly aligned single-and double-strand Si nano-ribbons on Ag(110)

    PubMed Central

    Cerdá, Jorge I.; Sławińska, Jagoda; Le Lay, Guy; Marele, Antonela C.; Gómez-Rodríguez, José M.; Dávila, María E.

    2016-01-01

    Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin–orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one. PMID:27708263

  8. Unveiling the pentagonal nature of perfectly aligned single-and double-strand Si nano-ribbons on Ag(110)

    NASA Astrophysics Data System (ADS)

    Cerdá, Jorge I.; Sławińska, Jagoda; Le Lay, Guy; Marele, Antonela C.; Gómez-Rodríguez, José M.; Dávila, María E.

    2016-10-01

    Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin-orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one.

  9. Coupled effect of size, strain rate, and temperature on the shape memory of a pentagonal Cu nanowire

    NASA Astrophysics Data System (ADS)

    Sutrakar, Vijay Kumar; Mahapatra, D. Roy

    2009-01-01

    A body-centered pentagonal nanobridge structure with lattice constants c = 2.35 and a = 2.53 Å has been observed under high strain rate tensile loading on an initially constrained \\langle 100\\rangle \\mbox {/} \\{100\\} Cu nanowire at various temperatures. Extensive molecular dynamics (MD) simulations have been performed using the embedded atom method (EAM) for cross-sectional dimensions ranging from 0.723 × 0.723 to 2.169 × 2.169 nm2, temperature ranging from 10 to 600 K, and strain rates of 109-107 s-1. Formations of such pentagonal nanowire are observed for a temperature range 200-600 K for particular cross-sectional dimensions and strain rates. A large inelastic deformation of ~50% is obtained under both isothermal loading and adiabatic loading. With very high degree of repeatability of such pentagonal nanowire formation, the present findings indicate that the interesting stability property and high strength of elongated nanowires have various potential applications in nanomechanical and nanoelectronic devices. Further, we demonstrate a novel thermomechanical unloading mechanism by which it is possible to impart recovery from a pentagonal nanowire following a hysteresis loop: \\langle 100\\rangle \\mbox {/}\\{100\\}\\to \\mathrm {pentagonal}\\to \\langle 110\\rangle \\mbox {/}\\{111\\}\\to \\langle 100\\rangle \\mbox {/} \\{100\\} .

  10. Fermion-scalar conformal blocks

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-04-13

    In this study, we compute the conformal blocks associated with scalar-scalar-fermionfermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. In addition, conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  11. Complete one-loop MSSM predictions for B{sup 0}{yields}l{sup +}l{sup '-} at the Tevatron and LHC

    SciTech Connect

    Dedes, Athanasios; Rosiek, Janusz; Tanedo, Philip

    2009-03-01

    During the last few years the Tevatron has dramatically improved the bounds on rare B-meson decays into two leptons. In the case of B{sub s}{sup 0}{yields}{mu}{sup +}{mu}{sup -}, the current bound is only 10 times greater than the standard model expectation. Sensitivity to this decay is one of the benchmark goals for LHCb performance and physics. The Higgs penguin dominates this rate in the region of large tan{beta} of the minimal supersymmetric standard model. This is not necessarily the case in the region of low tan{beta}, since box and Z-penguin diagrams may contribute at a comparable rate. In this article, we compute the complete one-loop minimal supersymmetric standard model contribution to B{sub s,d}{sup 0}{yields}l{sup +}l{sup '-} for l, l{sup '}=e, {mu}. We study the predictions for general values of tan{beta} with arbitrary flavor mixing parameters. We discuss the possibility of both enhancing and suppressing the branching ratios relative to their standard model expectations. In particular, we find that there are 'cancellation regions' in parameter space where the branching ratio is suppressed well below the standard model expectation, making it effectively invisible to the LHC.

  12. Endohedral nickel, palladium, and platinum atoms in 10-vertex germanium clusters: competition between bicapped square antiprismatic and pentagonal prismatic structures.

    PubMed

    King, R B; Silaghi-Dumitrescu, I; Uţa, M M

    2009-01-22

    Density functional theory predicts significant differences in the preferred structures of endohedral M@Ge10z (M = Ni, Pd, Pt; z = 0, 2-, 4-) clusters upon a change of the central metal atom in otherwise isoelectronic systems. For the neutral clusters M@Ge10 the global minima are singlet bicapped square antiprisms. However, triplet regular pentagonal prismatic structures become increasingly energetically competitive in the series Ni --> Pd -> Pt. The pentagonal prismatic dianions M@Ge10(2-) (M = Ni, Pd, Pt) appear to have closed shell structures and are the global minima for palladium and platinum. However, the global minimum for Ni@Ge102- is the capped square antiprism suggested by the Wade-Mingos rules. A number of singlet low-energy unsymmetrical structures are found for the tetraanions M@Ge10(4-). However, for the palladium and platinum tetraanions triplet pentagonal prismatic structures are energetically competitive with the unsymmetrical structures.

  13. Structure of force networks in tapped particulate systems of disks and pentagons. II. Persistence analysis

    NASA Astrophysics Data System (ADS)

    Kondic, L.; Kramár, M.; Pugnaloni, Luis A.; Carlevaro, C. Manuel; Mischaikow, K.

    2016-06-01

    In the companion paper [Pugnaloni et al., Phys. Rev. E 93, 062902 (2016), 10.1103/PhysRevE.93.062902], we use classical measures based on force probability density functions (PDFs), as well as Betti numbers (quantifying the number of components, related to force chains, and loops), to describe the force networks in tapped systems of disks and pentagons. In the present work, we focus on the use of persistence analysis, which allows us to describe these networks in much more detail. This approach allows us not only to describe but also to quantify the differences between the force networks in different realizations of a system, in different parts of the considered domain, or in different systems. We show that persistence analysis clearly distinguishes the systems that are very difficult or impossible to differentiate using other means. One important finding is that the differences in force networks between disks and pentagons are most apparent when loops are considered: the quantities describing properties of the loops may differ significantly even if other measures (properties of components, Betti numbers, force PDFs, or the stress tensor) do not distinguish clearly or at all the investigated systems.

  14. Structure of force networks in tapped particulate systems of disks and pentagons. II. Persistence analysis.

    PubMed

    Kondic, L; Kramár, M; Pugnaloni, Luis A; Carlevaro, C Manuel; Mischaikow, K

    2016-06-01

    In the companion paper [Pugnaloni et al., Phys. Rev. E 93, 062902 (2016)10.1103/PhysRevE.93.062902], we use classical measures based on force probability density functions (PDFs), as well as Betti numbers (quantifying the number of components, related to force chains, and loops), to describe the force networks in tapped systems of disks and pentagons. In the present work, we focus on the use of persistence analysis, which allows us to describe these networks in much more detail. This approach allows us not only to describe but also to quantify the differences between the force networks in different realizations of a system, in different parts of the considered domain, or in different systems. We show that persistence analysis clearly distinguishes the systems that are very difficult or impossible to differentiate using other means. One important finding is that the differences in force networks between disks and pentagons are most apparent when loops are considered: the quantities describing properties of the loops may differ significantly even if other measures (properties of components, Betti numbers, force PDFs, or the stress tensor) do not distinguish clearly or at all the investigated systems. PMID:27415343

  15. Structure of force networks in tapped particulate systems of disks and pentagons. II. Persistence analysis.

    PubMed

    Kondic, L; Kramár, M; Pugnaloni, Luis A; Carlevaro, C Manuel; Mischaikow, K

    2016-06-01

    In the companion paper [Pugnaloni et al., Phys. Rev. E 93, 062902 (2016)10.1103/PhysRevE.93.062902], we use classical measures based on force probability density functions (PDFs), as well as Betti numbers (quantifying the number of components, related to force chains, and loops), to describe the force networks in tapped systems of disks and pentagons. In the present work, we focus on the use of persistence analysis, which allows us to describe these networks in much more detail. This approach allows us not only to describe but also to quantify the differences between the force networks in different realizations of a system, in different parts of the considered domain, or in different systems. We show that persistence analysis clearly distinguishes the systems that are very difficult or impossible to differentiate using other means. One important finding is that the differences in force networks between disks and pentagons are most apparent when loops are considered: the quantities describing properties of the loops may differ significantly even if other measures (properties of components, Betti numbers, force PDFs, or the stress tensor) do not distinguish clearly or at all the investigated systems.

  16. The formation of pentagon-heptagon pair defect by the reconstruction of vacancy defects in carbon nanotube

    NASA Astrophysics Data System (ADS)

    Lee, Gun-Do; Wang, C. Z.; Yoon, Euijoon; Hwang, Nong-Moon; Ho, K. M.

    2008-01-01

    The reconstruction process of vacancy hole in carbon nanotube is investigated by tight-binding molecular dynamics simulations and by ab initio total energy calculations. In the molecular dynamics simulation, a vacancy hole is found to reconstruct into two separated pentagon-heptagon pair defects. As the result of reconstruction, the radius of the carbon nanotube is reduced and the chirality of the tube is partly changed. During the vacancy hole healing process, the formation of pentagonal and heptagonal rings is proceeded by the subsequent Stone-Wales [Chem. Phys. Lett. 128, 501 (1986)] transformation.

  17. The formation of pentagon-heptagon pair defect by the reconstruction og vacancy defects in carbon nanotube

    SciTech Connect

    Lee, G.D.; Wang, C.Z.; Yoon, E.; Hwang, N.M.; Ho, K.M.

    2008-01-29

    The reconstruction process of vacancy hole in carbon nanotube is investigated by tight-binding molecular dynamics simulations and by ab initio total energy calculations. In the molecular dynamics simulation, a vacancy hole is found to reconstruct into two separated pentagon-heptagon pair defects. As the result of reconstruction, the radius of the carbon nanotube is reduced and the chirality of the tube is partly changed. During the vacancy hole healing process, the formation of pentagonal and heptagonal rings is proceeded by the subsequent Stone-Wales.

  18. Light scalar susceptibilities and the {pi}{sup 0}-{eta} mixing

    SciTech Connect

    Torres Andres, Ricardo; Gomez Nicola, Angel

    2011-05-23

    We have performed a thermal analysis of the light scalar susceptibilities in the context of SU(3)-Chiral Perturbation Theory to one loop taking into account the QCD source of isospin breaking (IB), i.e corrections coming from m{sub u{ne}}m{sub d}. We find that the value of the connected scalar susceptibility in the infrared regime and below the critical temperature is entirely dominated by the {pi}{sup 0}-{eta} mixing, which leads to model-independent O(Vegr;{sup 0}) corrections, where {epsilon}{approx}m{sub d}-m{sub u}, in the combination {chi}{sub uu}-{chi}{sub ud} of flavour breaking susceptibilities.

  19. Electroweak Baryogenesis and Colored Scalars

    SciTech Connect

    Cohen, Timothy; Pierce, Aaron; /Michigan U., MCTP

    2012-02-15

    We consider the 2-loop finite temperature effective potential for a Standard Model-like Higgs boson, allowing Higgs boson couplings to additional scalars. If the scalars transform under color, they contribute 2-loop diagrams to the effective potential that include gluons. These 2-loop effects are perhaps stronger than previously appreciated. For a Higgs boson mass of 115 GeV, they can increase the strength of the phase transition by as much as a factor of 3.5. It is this effect that is responsible for the survival of the tenuous electroweak baryogenesis window of the Minimal Supersymmetric Standard Model. We further illuminate the importance of these 2-loop diagrams by contrasting models with colored scalars to models with singlet scalars. We conclude that baryogenesis favors models with light colored scalars. This motivates searches for pair-produced di-jet resonances or jet(s) + = E{sub T}.

  20. Scalar-tensor theories with an external scalar

    NASA Astrophysics Data System (ADS)

    Chauvineau, Bertrand; Rodrigues, Davi C.; Fabris, Júlio C.

    2016-06-01

    Scalar-tensor (ST) gravity is considered in the case where the scalar is an external field. We show that general relativity (GR) and usual ST gravity are particular cases of the external scalar-tensor (EST) gravity. It is shown with a particular cosmological example that it is possible to join a part of a GR solution to a part of a ST one such that the complete solution neither belongs to GR nor to ST, but fully satisfies the EST field equations. We argue that external fields may effectively work as a type of screening mechanism for ST theories.

  1. Scalar mode propagation in modified gravity with a scalar field

    SciTech Connect

    De Felice, Antonio; Suyama, Teruaki

    2009-10-15

    We study the propagation of the scalar modes around a Friedmann-Lemaitre-Robertson-Walker universe for general modifications of gravity in the presence of a real scalar field. In general, there will be two propagating scalar perturbation fields, which will have in total 4 degrees of freedom. Two of these degrees will have a superluminal propagation - with k-dependent speed of propagation - whereas the other two will have the speed of light. Therefore, the scalar degrees of freedom do not modify the general feature of modified gravity models: the appearance of modes whose frequency depends on the second power of the modulus of the wave vector. Constraints are given and special cases are discussed.

  2. Are stealth scalar fields stable?

    SciTech Connect

    Faraoni, Valerio; Moreno, Andres F. Zambrano

    2010-06-15

    Nongravitating (stealth) scalar fields associated with Minkowski space in scalar-tensor gravity are examined. Analytical solutions for both nonminimally coupled scalar field theory and for Brans-Dicke gravity are studied and their stability with respect to tensor perturbations is assessed using a covariant and gauge-invariant formalism developed for alternative gravity. For Brans-Dicke solutions, the stability with respect to homogeneous perturbations is also studied. There are regions of parameter space corresponding to stability and other regions corresponding to instability.

  3. Is Julian Assange an International Version of Daniel Ellsberg and WikiLeaks the Modern Equivalent of the Pentagon Papers?

    ERIC Educational Resources Information Center

    Freivogel, William H.

    2011-01-01

    History has placed the stamp of approval on the publication of the Pentagon Papers, the top-secret history of the Vietnam War. If WikiLeaks editor-in-chief Julian Assange is another Daniel Ellsberg, then it is possible the website's disclosures will be viewed over time as similarly in the public interest. A classroom discussion on the release of…

  4. Flexible structural and electronic properties of a pentagonal B2C monolayer via external strain: a computational investigation.

    PubMed

    Li, Fengyu; Tu, Kaixiong; Zhang, Haijun; Chen, Zhongfang

    2015-10-01

    Inspired by the recent theoretical finding that penta-graphene, composed entirely of carbon pentagons, is dynamically and mechanically stable [Proc. Natl. Acad. Sci. U. S. A., 2015, 112, 2372-2377], we computationally designed a new two-dimensional (2D) inorganic material, a pentagonal B2C monolayer (penta-B2C), in which each pentagon contains three boron and two carbon atoms, the C atom is four-coordinated with four B atoms, and all the B atoms are three-coordinated with two C atoms and one B atom, forming a buckled 2D network. The pentagonal B2C monolayer is semiconducting with a wide indirect band gap of 2.28 eV from HSE calculations. The absence of imaginary modes in its phonon spectrum, and the high melting point predicted by molecular dynamics (MD) simulations indicate its good stability. Interestingly, the buckled structure could be stretched to planar under 15% biaxial tensile strain, and the band gap will be strikingly reduced to 0.06 eV. The semiconducting properties of penta-B2C could also be switched to those of a metallic semiconductor under certain biaxial strains, while uniaxial strains could only tune the band gaps without changing the semiconducting characteristics.

  5. Flexible structural and electronic properties of a pentagonal B2C monolayer via external strain: a computational investigation.

    PubMed

    Li, Fengyu; Tu, Kaixiong; Zhang, Haijun; Chen, Zhongfang

    2015-10-01

    Inspired by the recent theoretical finding that penta-graphene, composed entirely of carbon pentagons, is dynamically and mechanically stable [Proc. Natl. Acad. Sci. U. S. A., 2015, 112, 2372-2377], we computationally designed a new two-dimensional (2D) inorganic material, a pentagonal B2C monolayer (penta-B2C), in which each pentagon contains three boron and two carbon atoms, the C atom is four-coordinated with four B atoms, and all the B atoms are three-coordinated with two C atoms and one B atom, forming a buckled 2D network. The pentagonal B2C monolayer is semiconducting with a wide indirect band gap of 2.28 eV from HSE calculations. The absence of imaginary modes in its phonon spectrum, and the high melting point predicted by molecular dynamics (MD) simulations indicate its good stability. Interestingly, the buckled structure could be stretched to planar under 15% biaxial tensile strain, and the band gap will be strikingly reduced to 0.06 eV. The semiconducting properties of penta-B2C could also be switched to those of a metallic semiconductor under certain biaxial strains, while uniaxial strains could only tune the band gaps without changing the semiconducting characteristics. PMID:26315808

  6. Scalar cosmological perturbations

    NASA Astrophysics Data System (ADS)

    Uggla, Claes; Wainwright, John

    2012-05-01

    Scalar perturbations of Friedmann-Lemaitre cosmologies can be analyzed in a variety of ways using Einstein’s field equations, the Ricci and Bianchi identities, or the conservation equations for the stress-energy tensor, and possibly introducing a timelike reference congruence. The common ground is the use of gauge invariants derived from the metric tensor, the stress-energy tensor, or from vectors associated with a reference congruence, as basic variables. Although there is a complication in that there is no unique choice of gauge invariants, we will show that this can be used to advantage. With this in mind our first goal is to present an efficient way of constructing dimensionless gauge invariants associated with the tensors that are involved, and of determining their inter-relationships. Our second goal is to give a unified treatment of the various ways of writing the governing equations in dimensionless form using gauge-invariant variables, showing how simplicity can be achieved by a suitable choice of variables and normalization factors. Our third goal is to elucidate the connection between the metric-based approach and the so-called 1 + 3 gauge-invariant approach to cosmological perturbations. We restrict our considerations to linear perturbations, but our intent is to set the stage for the extension to second-order perturbations.

  7. Two-dimensional pentagonal crystals and possible spin-polarized Dirac dispersion relations

    SciTech Connect

    Tang, Chi-Pui; Xiong, Shi-Jie Shi, Wu-Jun; Cao, Jie

    2014-03-21

    Based on first-principles calculations we show that the two-dimensional pentagonal (pt) structures, the compositions of pt-BN{sub 2}, pt-C, and pt-Fe{sub 2}S, are stable. As a common feature, they are composed of 3 components: 2 stretched honeycomb sublattices and 1 square sublattice, conferring flexibility of tailoring the properties peculiar to the graphene. Although the Dirac dispersion relation is removed in metallic pt-BN{sub 2} and insulating pt-C due to the hybridization of two honeycomb sublattices, it survives in pt-Fe{sub 2}S because of the suppression of such hybridization between different spins. As a result, in the dispersion relation of pt-Fe{sub 2}S spin-polarized and anisotropic Dirac cones occur. We suggest that such type of dispersion relation can be used to produce spin-filter effect by applying electric bias in a specific direction.

  8. The Regioselectivity of Bingel-Hirsch Cycloadditions on Isolated Pentagon Rule Endohedral Metallofullerenes.

    PubMed

    Garcia-Borràs, Marc; Cerón, Maira R; Osuna, Sílvia; Izquierdo, Marta; Luis, Josep M; Echegoyen, Luis; Solà, Miquel

    2016-02-12

    In this work, the Bingel-Hirsch addition of diethylbromomalonate to all non-equivalent bonds of Sc3N@D3h -C78 was studied using density functional theory calculations. The regioselectivities observed computationally allowed the proposal of a set of rules, the predictive aromaticity criteria (PAC), to identify the most reactive bonds of a given endohedral metallofullerene based on a simple evaluation of the cage structure. The predictions based on the PAC are fully confirmed by both the computational and experimental exploration of the Bingel-Hirsch reaction of Sc3N@D5h -C80, thus indicating that these rules are rather general and applicable to other isolated pentagon rule endohedral metallofullerenes.

  9. Reagan's energy war: can deregulation and the Pentagon save the nuclear industry

    SciTech Connect

    Feeney, A.

    1981-11-01

    Mr. Feeney feels that Administration energy policies claiming to protect democracy and reduce government interference will transfer money and political control from the people to the energy corporations and the Pentagon. Critics deplore the hard-path approach of downgrading conservation and solar energy in favor of nuclear energy, which some see as setting the stage for a nuclear war in this decade. They see the plan to abolish DOE as providing an opportunity to bail out the nuclear industry, bury environmental and alternative energy research, and block regulations. Critics question why Reagan's devotion to the free market is not applied to the nuclear industry, although they disagree on the linkage with nuclear weapons of new fuel cycle proposals and the use of national security to solve the waste disposal problem by nationalizing and militarizing the fuel cycle. (DCK)

  10. Nanosurgery in Carbon Nanotubes: Efficient Elimination of Pentagon-Heptagon Defects Using Femtosecond Laser Pulses

    NASA Astrophysics Data System (ADS)

    Garcia, Martin; Romero, Aldo; Jeschke, Harald

    2005-03-01

    Using non-adiabatic molecular dynamics simulations we demonstrate that femtosecond laser pulses are able to eliminate pentagon-heptagon defects within carbon nanotubes. We conclude that ultrafast healing of zig-zag and armchair nanotubes can be achieved with pulse durations of 50 fs within a wide range of laser intensities. This nonthermal transition occurs at a relatively low lattice temperature (˜450 K) and is driven by the electronic entropy, which is dramatically increased by the action of the laser pulse, thus causing 5-7-5-7 defects to become unstable at very high electronic temperatures. The intermediate steps of the inverse Stone-Wales-type transformation are qualitatively different from those occurring in thermally driven phenomena.

  11. "The only feasible means." The Pentagon's ambivalent relationship with the Nuremberg Code.

    PubMed

    Moreno, J D

    1996-01-01

    Convinced that armed conflict with the Soviet Union was all but inevitable, that such conflict would involve unconventional atomic, biological, and chemical warfare, and that research with human subjects was essential to respond to the threat, in the early 1950s the U.S. Department of Defense promulgated a policy governing human experimentation based on the Nuremberg Code. Yet the policymaking process focused on the abstract issue of whether human experiments should go forward at all, ignoring the reality of humans subjects research already under way and leaving unanswered ethical questions about how to conduct such research. Documents newly released to the Advisory Committee on Human Radiation Experiments tell the story of the Pentagon policy.

  12. Performance and Maqasid al-Shari'ah's Pentagon-Shaped Ethical Measurement.

    PubMed

    Bedoui, Houssem Eddine; Mansour, Walid

    2015-06-01

    Business performance is traditionally viewed from the one-dimensional financial angle. This paper develops a new approach that links performance to the ethical vision of Islam based on maqasid al-shari'ah (i.e., the objectives of Islamic law). The approach involves a Pentagon-shaped performance scheme structure via five pillars, namely wealth, posterity, intellect, faith, and human self. Such a scheme ensures that any firm or organization can ethically contribute to the promotion of human welfare, prevent corruption, and enhance social and economic stability and not merely maximize its own performance in terms of its financial return. A quantitative measure of ethical performance is developed. It surprisingly shows that a firm or organization following only the financial aspect at the expense of the others performs poorly. This paper discusses further the practical instances of the quantitative measurement of the ethical aspects of the system taken at an aggregate level.

  13. Endohedrally stabilized C70 isomer with fused pentagons characterized by crystallography.

    PubMed

    Feng, Lai; Zhang, Meirong; Hao, Yajuan; Tang, Qiangqiang; Chen, Ning; Slanina, Zdeněk; Uhlík, Filip

    2016-05-10

    Besides the conventional D5h(8149)-C70 fullerene, there are a large number of C70 isomers that violate the isolated pentagon rule (IPR). However, these non-IPR C70 fullerenes have been less investigated owing to their low stabilities or high reactivities. In this study, we report for the first time the X-ray structure of an unconventional endohedral C70 fullerene, Sc2O@C2(7892)-C70. The combined study of geometrical analysis and computation further reveals the ionic and covalent interactions between the cluster and the cage, both of which contribute to the stabilization of this non-IPR C70 fullerene. In addition, a close structural relationship between the non-IPR C2(7892)-C70 and the IPR D5h(8149)-C70 has been demonstrated, which might provide an alternative explanation of the formation of non-IPR fullerenes. PMID:27090070

  14. The Regioselectivity of Bingel-Hirsch Cycloadditions on Isolated Pentagon Rule Endohedral Metallofullerenes.

    PubMed

    Garcia-Borràs, Marc; Cerón, Maira R; Osuna, Sílvia; Izquierdo, Marta; Luis, Josep M; Echegoyen, Luis; Solà, Miquel

    2016-02-12

    In this work, the Bingel-Hirsch addition of diethylbromomalonate to all non-equivalent bonds of Sc3N@D3h -C78 was studied using density functional theory calculations. The regioselectivities observed computationally allowed the proposal of a set of rules, the predictive aromaticity criteria (PAC), to identify the most reactive bonds of a given endohedral metallofullerene based on a simple evaluation of the cage structure. The predictions based on the PAC are fully confirmed by both the computational and experimental exploration of the Bingel-Hirsch reaction of Sc3N@D5h -C80, thus indicating that these rules are rather general and applicable to other isolated pentagon rule endohedral metallofullerenes. PMID:26765333

  15. Symmetry inheritance of scalar fields

    NASA Astrophysics Data System (ADS)

    Smolić, Ivica

    2015-07-01

    Matter fields do not necessarily have to share the symmetries with the spacetime they live in. When this happens, we speak of the symmetry inheritance of fields. In this paper we classify the obstructions of symmetry inheritance by the scalar fields, both real and complex, and look more closely at the special cases of stationary and axially symmetric spacetimes. Since the symmetry noninheritance is present in the scalar fields of boson stars and may enable the existence of the black hole scalar hair, our results narrow the possible classes of such solutions. Finally, we define and analyse the symmetry noninheritance contributions to the Komar mass and angular momentum of the black hole scalar hair.

  16. Scalar graviton as dark matter

    SciTech Connect

    Pirogov, Yu. F.

    2015-06-15

    The basics of the theory of unimodular bimode gravity built on the principles of unimodular gauge invariance/relativity and general covariance are exposed. Besides the massless tensor graviton of General Relativity, the theory includes an (almost) massless scalar graviton treated as the gravitational dark matter. A spherically symmetric vacuum solution describing the coherent scalar-graviton field for the soft-core dark halos, with the asymptotically flat rotation curves, is demonstrated as an example.

  17. Color Sextet Scalars in Early LHC Experiments

    SciTech Connect

    Berger, Edmond L.; Cao Qinghong; Chen, Chuan-Ren; Shaughnessy, Gabe; Zhang Hao

    2010-10-29

    We explore the potential for discovery of an exotic color sextet scalar in same-sign top quark pair production in early running at the LHC. We present the first phenomenological analysis at colliders of color sextet scalars with full top quark spin correlations included. We demonstrate that one can measure the scalar mass, the top quark polarization, and confirm the scalar resonance with 1 fb{sup -1} of integrated luminosity. The top quark polarization can distinguish gauge triplet and singlet scalars.

  18. The emergence of scalar meanings

    PubMed Central

    Etxeberria, Urtzi; Irurtzun, Aritz

    2015-01-01

    This paper analyzes the emergence of scalar additive meanings. We show that in Basque the same particle ere can obtain both the “simple additive” reading (akin to English too) and the “scalar additive” reading (akin to English even) but we argue that we do not have to distinguish two types of ere. We provide evidence, by means of a production and a perception experiment, that the reading is disambiguated by means of prosody (the placement of nuclear stress), which is a correlate of focus. We argue that the scalarity effect is generated by the combination of two presuppositions (a focus-induced one and a lexical one) and the assertion of the sentence. PMID:25745405

  19. Scalar-tensor cosmological models

    NASA Astrophysics Data System (ADS)

    Serna, A.; Alimi, J. M.

    1996-03-01

    We analyze the qualitative behavior of scalar-tensor cosmologies with an arbitrary monotonic $\\omega(\\Phi)$ function. In particular, we are interested in scalar-tensor theories distinguishable at early epochs from general relativity (GR) but leading to predictions compatible with solar-system experiments. After extending the method developed by Lorentz-Petzold and Barrow, we establish the conditions required for convergence towards GR at $t \\rightarrow \\infty$. Then, we obtain all the asymptotic analytical solutions at early times which are possible in the framework of these theories. The subsequent qualitative evolution, from these asymptotic solutions until their later convergence towards GR, is analyzed by means of numerical computations. From this analysis, we are able to establish a classification of the different qualitative behaviors of scalar-tensor cosmological models with an arbitrary monotonic $\\omega(\\Phi)$ function

  20. Scalar transport by planktonic swarms

    NASA Astrophysics Data System (ADS)

    Martinez-Ortiz, Monica; Dabiri, John O.

    2012-11-01

    Nutrient and energy transport in the ocean is primarily governed by the action of physical phenomena. In previous studies it has been suggested that aquatic fauna may significantly contribute to this process through the action of the induced drift mechanism. In this investigation, the role of planktonic swarms as ecosystem engineers is assessed through the analysis of scalar transport within a stratified water column. The vertical migration of Artemia salina is controlled via luminescent signals on the top and bottom of the column. The scalar transport of fluorescent dye is visualized and quantified through planar laser induced fluorescence (PLIF). Preliminary results show that the vertical movement of these organisms enhances scalar transport relative to control cases in which only buoyancy forces and diffusion are present. Funded by the BSF program (2011553).

  1. Migrations of pentagon-heptagon defects in hexagonal boron nitride monolayer: the first-principles study.

    PubMed

    Wang, J; Li, S N; Liu, J B

    2015-04-16

    The first-principles calculations are employed to study the migrations of pentagon-heptagon (5-7) defects in hexagonal boron nitride monolayer (h-BN). A type of grain boundaries, consisted of 5-7 defects, is constructed on the basis of experimental observations. With the absorption of a pair of atoms, one 5-7 defect in the grain boundary migrates apart by one unit cell and afterward migrates again through the bond rotation. It is also found that the two migrations could be replaced by one single step when the pair of absorbed atoms is located at another specific site in the same heptagon. Energy barriers and reaction paths for the migrations of 5-7 defects in h-BN by the bond rotation are theoretically investigated by the standard nudged elastic band method and the generalized solid-state nudged elastic band method. To elucidate the difference between the bond rotation process of the 5-7 defects with N-N bonds and those with B-B bonds, a couple of typical 21.7° grain boundaries with either N-N or B-B bonds are investigated. It is shown that the energy barrier of the migration of defects with N-N bonds is lower than that with B-B bonds in this type of grain boundaries. PMID:25811102

  2. Translation symmetry breakdown in low-dimensional lattices of pentagonal rings.

    PubMed

    Avramov, Paul; Demin, Victor; Luo, Ming; Choi, Cheol Ho; Sorokin, Pavel B; Yakobson, Boris; Chernozatonskii, Leonid

    2015-11-19

    The mechanism of translation symmetry breakdown in newly proposed low-dimensional carbon pentagon-constituted nanostructures (e.g., pentagraphene) with multiple sp(2)/sp(3) sublattices was studied by GGA DFT, DFTB, and model potential approaches. It was found that finite nanoclusters suffer strong uniform unit cell bending followed by breaking of crystalline lattice linear translation invariance caused by structural mechanical stress. It was shown that 2D sp(2)/sp(3) nanostructures are correlated transition states between two symmetrically equivalent bent structures. At DFT level of theory the distortion energy of the flakes (7.5 × 10(-2) eV/atom) is much higher the energy of dynamical stabilization of graphene. Strong mechanical stress prevents stabilization of the nanoclusters on any type of supports by either van der Waals or covalent bonding and should lead to formation of pentatubes, nanorings, or nanofoams rather than infinite nanoribbons or nanosheets. Formation of two-layered pentagraphene structures leads to compensation of the stress and stabilization of flat finite pentaflakes. PMID:26582476

  3. Energetic analysis of pentagon road intermediates of C{sub 60}-buckminsterfullerene formation

    SciTech Connect

    Bates, K.R.; Scuseria, G.E.

    1997-04-17

    We report an energetic analysis of the principal intermediates of the pentagon road (PR) scheme for formation of C{sub 60}-Buckminsterfullerene. All calculations were initially performed using the tight-binding semiempirical method. For selected cases, more rigorous 3-21G/HF and 3-21G/B3LYP calculations were carried out. The first part of this study includes an energetic comparison between the 30-, 40-, and 50-atom PR intermediates and a representative group of 30-, 40-, and 50-atom carbon clusters. While C{sub 30} PR is higher in energy than a large variety of graphene sheets and fullerenes, C{sub 40} PR and C{sub 50} PR are considerably lower in energy than many other isomers; only fullerenes are more stable. Additionally, we examine a plausible mechanism by which C{sub 50} PR rearranges to form a C{sub 50} cage with D{sub 5h} symmetry. Because of its large energy barrier, this process is unlikely to affect the C{sub 60} growth mechanism. 17 refs., 9 figs., 3 tabs.

  4. Scalar fields and particle accelerators

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph; Bose, Benjamin

    2015-06-01

    The phenomenon discovered in 2009 by Bañados, Silk and West where particle collisions can achieve arbitrary high center-of-mass (c.m.) energies close to the event horizon of an extreme Kerr black hole, has generated a lot of interest. Although rotation seemed to be an essential requirement, it was later shown that arbitrary high energies can also be achieved for collisions between radially moving particles near the horizon of the electrically charged extreme Reissner-Nordström black hole. Recently Patil and Joshi claimed that instead of spinning up the black hole one can also crank up the c.m. energy of particle collisions by "charging up" a static black hole with a massless scalar field. In this regard they showed that infinite energies can be attained in the vicinity of the naked singularity of the Janis-Newman-Wincour (JNW) spacetime, which contains a massless scalar field that also becomes infinite at the position of the curvature singularity. In this study we show that Patil and Joshi's claim does not apply for other static black hole systems endowed with a massless scalar field. In particular we consider the well-known Bekenstein black hole and the recently discovered Martínez-Troncoso-Zanelli black hole, and show that the expression of the c.m. energy for particle collisions near the event horizons of these black holes is no different than the corresponding case with vanishing scalar field represented by the Schwarzschild solution. Moreover by studying the motion of scalar test charges that interact with the background scalar field in these black hole spacetimes we show that the resulting c.m. energies are even smaller than in the case of free particles. This shows that the infinite energies obtained by Patil and Joshi may not be due to the fact that the black hole contains a massless scalar field, but may be instead related to the geometry of the naked singularity in the JNW spacetime. An analogous case of infinite c.m. energy in the vicinity of a naked

  5. Scalar limitations of diffractive optical elements

    NASA Technical Reports Server (NTRS)

    Johnson, Eric G.; Hochmuth, Diane; Moharam, M. G.; Pommet, Drew

    1993-01-01

    In this paper, scalar limitations of diffractive optic components are investigated using coupled wave analyses. Results are presented for linear phase gratings and fanout devices. In addition, a parametric curve is given which correlates feature size with scalar performance.

  6. MAGSAT scalar and vector anomaly data analysis

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Efforts on the analysis of MAGSAT scalar anomaly data, the application of the scalar analysis results to three component vector data, and the comparison of MAGSAT data with corresponding MAGNET aeromagnetic and free air gravity anomaly data are briefly described.

  7. C74 endohedral metallofullerenes violating the isolated pentagon rule: a density functional theory study

    NASA Astrophysics Data System (ADS)

    Zheng, Hong; Zhao, Xiang; Ren, Ting; Wang, Wei-Wei

    2012-07-01

    Precise studies on M2@C74 (M = Sc, La) series by means of DFT methods have disclosed that certain non-IPR isomers are more stable than the IPR structure. M2@C2(13295)-C74 and M2@C2(13333)-C74, both of which have two pentagon adjacencies (PA), present excellent thermodynamic stability with very small energy differences. Statistical mechanics calculations on the M2@C74 series reveal that M2@C2(13295)-C74 and M2@C2(13333)-C74 are quite favoured by entropy effects below 3000 K. Sc2@C74 and La2@C74 series are found to have similar electronic transfer but different electronic structures due to the distinct properties of scandium and lanthanum elements according to Natural Bond Orbital (NBO) analysis in conjunction with orbital interaction diagrams. Investigations of bonding energies reflect quite different influences of the two types of metal atoms to C74 metallo-fullerenes. Further examinations on C74 metallo-fullerenes uncover significant stabilization effects of metal atoms acting on PA fragments. Geometrical structures of certain non-IPR cages (from C72 to C76), which exhibit splendid stabilities when encapsulating metallo-clusters, are found to be related by Stone-Wales transformation and C2 addition. Furthermore, IR spectra and 13C NMR spectra of M2@C2(13295)-C74 and M2@C2(13333)-C74 have been simulated to assist further experimental characterization.Precise studies on M2@C74 (M = Sc, La) series by means of DFT methods have disclosed that certain non-IPR isomers are more stable than the IPR structure. M2@C2(13295)-C74 and M2@C2(13333)-C74, both of which have two pentagon adjacencies (PA), present excellent thermodynamic stability with very small energy differences. Statistical mechanics calculations on the M2@C74 series reveal that M2@C2(13295)-C74 and M2@C2(13333)-C74 are quite favoured by entropy effects below 3000 K. Sc2@C74 and La2@C74 series are found to have similar electronic transfer but different electronic structures due to the distinct properties of

  8. C₇₄ endohedral metallofullerenes violating the isolated pentagon rule: a density functional theory study.

    PubMed

    Zheng, Hong; Zhao, Xiang; Ren, Ting; Wang, Wei-Wei

    2012-08-01

    Precise studies on M(2)@C(74) (M = Sc, La) series by means of DFT methods have disclosed that certain non-IPR isomers are more stable than the IPR structure. M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74), both of which have two pentagon adjacencies (PA), present excellent thermodynamic stability with very small energy differences. Statistical mechanics calculations on the M(2)@C(74) series reveal that M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74) are quite favoured by entropy effects below 3000 K. Sc(2)@C(74) and La(2)@C(74) series are found to have similar electronic transfer but different electronic structures due to the distinct properties of scandium and lanthanum elements according to Natural Bond Orbital (NBO) analysis in conjunction with orbital interaction diagrams. Investigations of bonding energies reflect quite different influences of the two types of metal atoms to C(74) metallo-fullerenes. Further examinations on C(74) metallo-fullerenes uncover significant stabilization effects of metal atoms acting on PA fragments. Geometrical structures of certain non-IPR cages (from C(72) to C(76)), which exhibit splendid stabilities when encapsulating metallo-clusters, are found to be related by Stone-Wales transformation and C(2) addition. Furthermore, IR spectra and (13)C NMR spectra of M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74) have been simulated to assist further experimental characterization.

  9. Bianchi I in scalar and scalar-tensor cosmologies

    NASA Astrophysics Data System (ADS)

    Belinchón, José

    2012-08-01

    We study how the constants G and Λ may vary in different theoretical models (general relativity (GR) with a perfect fluid, scalar cosmological models (SM) ("quintessence") with and without interacting scalar and matter fields and three scalar-tensor theories (STT) with a dynamical Λ) in order to explain some observational results. We apply the program outlined in section II to study the Bianchi I models, under the self-similarity hypothesis. We put special emphasis on calculating exact power-law solutions which allow us to compare the different models. In all the studied cases we conclude that the solutions are isotropic and noninflationary. We also arrive at the conclusion that in the GR model with time-varying constants, Λ vanishes while G is constant. In the SM all the solutions are massless i.e. the potential vanishes and all the interacting models are inconsistent from the thermodynamical point of view. The solutions obtained in the STT collapse to the perfect fluid one obtained in the GR model where G is a true constant and Λ vanishes as in the GR and SM frameworks.

  10. Constrained inflaton due to a complex scalar

    SciTech Connect

    Budhi, Romy H. S.; Kashiwase, Shoichi; Suematsu, Daijiro

    2015-09-14

    We reexamine inflation due to a constrained inflaton in the model of a complex scalar. Inflaton evolves along a spiral-like valley of special scalar potential in the scalar field space just like single field inflation. Sub-Planckian inflaton can induce sufficient e-foldings because of a long slow-roll path. In a special limit, the scalar spectral index and the tensor-to-scalar ratio has equivalent expressions to the inflation with monomial potential φ{sup n}. The favorable values for them could be obtained by varying parameters in the potential. This model could be embedded in a certain radiative neutrino mass model.

  11. Radiation patterns of 'scalar' lightpipes

    NASA Astrophysics Data System (ADS)

    Padman, Rachael; Murphy, J. A.

    At long wavelengths, diffraction effects cause condensing lightpipes to have a significant response in directions within the geometric-optics shadow zone. Here, using an analogy with the corrugated 'scalar' horns often used in antenna engineering, it is suggested that a lightpipe with anisotropic surface impedance on its interior surfaces can have substantially reduced sidelobe levels. This may be important for measurements requiring high dynamic range, particularly in the far-IR.

  12. Scalar meson f{sub 0}(980) in heavy-meson decays.

    SciTech Connect

    El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.; Physics; Lab. de Physique Nucleaire et de Hautes Energies; Lab. Nazionali di Frascati

    2009-04-01

    A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s} {yields} f{sub 0}(980)P, with P = {pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s} {yields} {pi}{pi}{pi}, K{sup -} K{pi} and from the f{sub 0}(980) {yields} {pi}{sup +}{pi}{sup -} and f{sub 0}(980) {yields} K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s} {yields} f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a q{bar q} state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of u{bar u}, d{bar d}, and s{bar s} pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s} {yields} f{sub 0}(980), as well as to make predictions for B and B{sub s} {yields} f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.

  13. Scalar meson f{sub 0}(980) in heavy-meson decays

    SciTech Connect

    El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.

    2009-04-01

    A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s}{yields}f{sub 0}(980)P, with P={pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s}{yields}{pi}{pi}{pi}, KK{pi} and from the f{sub 0}(980){yields}{pi}{sup +}{pi}{sup -} and f{sub 0}(980){yields}K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s}{yields}f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a qq state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of uu, dd, and ss pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s}{yields}f{sub 0}(980), as well as to make predictions for B and B{sub s}{yields}f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.

  14. Entropic quantization of scalar fields

    SciTech Connect

    Ipek, Selman; Caticha, Ariel

    2015-01-13

    Entropic Dynamics is an information-based framework that seeks to derive the laws of physics as an application of the methods of entropic inference. The dynamics is derived by maximizing an entropy subject to constraints that represent the physically relevant information that the motion is continuous and non-dissipative. Here we focus on the quantum theory of scalar fields. We provide an entropic derivation of Hamiltonian dynamics and using concepts from information geometry derive the standard quantum field theory in the Schrödinger representation.

  15. Slowly rotating neutron stars in scalar-tensor theories with a massive scalar field

    NASA Astrophysics Data System (ADS)

    Yazadjiev, Stoytcho S.; Doneva, Daniela D.; Popchev, Dimitar

    2016-04-01

    In the scalar-tensor theories with a massive scalar field, the coupling constants, and the coupling functions in general, which are observationally allowed, can differ significantly from those in the massless case. This fact naturally implies that the scalar-tensor neutron stars with a massive scalar field can have rather different structure and properties in comparison with their counterparts in the massless case and in general relativity. In the present paper, we study slowly rotating neutron stars in scalar-tensor theories with a massive gravitational scalar. Two examples of scalar-tensor theories are examined—the first example is the massive Brans-Dicke theory and the second one is a massive scalar-tensor theory indistinguishable from general relativity in the weak-field limit. In the latter case, we study the effect of the scalar field mass on the spontaneous scalarization of neutron stars. Our numerical results show that the inclusion of a mass term for the scalar field indeed changes the picture drastically compared to the massless case. It turns out that mass, radius, and moment of inertia for neutron stars in massive scalar-tensor theories can differ drastically from the pure general relativistic solutions if sufficiently large masses of the scalar field are considered.

  16. Symmetry-Supported Magnetic Blocking at 20 K in Pentagonal Bipyramidal Dy(III) Single-Ion Magnets.

    PubMed

    Chen, Yan-Cong; Liu, Jun-Liang; Ungur, Liviu; Liu, Jiang; Li, Quan-Wen; Wang, Long-Fei; Ni, Zhao-Ping; Chibotaru, Liviu F; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-03-01

    Single-molecule magnets (SMMs) that can be trapped in one of the bistable magnetic states separated by an energy barrier are among the most promising candidates for high-density information storage, quantum processing, and spintronics. To date, a considerable series of achievements have been made. However, the presence of fast quantum tunnelling of magnetization (QTM) in most SMMs, especially in single-ion magnets (SIMs), provides a rapid relaxation route and often sets up a limit for the relaxation time. Here, we pursue the pentagonal bipyramidal symmetry to suppress the QTM and present pentagonal bipyramidal Dy(III) SIMs [Dy(Cy3PO)2(H2O)5]Cl3·(Cy3PO)·H2O·EtOH (1) and [Dy(Cy3PO)2(H2O)5]Br3·2(Cy3PO)·2H2O·2EtOH (2), (Cy3PO = tricyclohexyl phosphine oxide). Magnetic characterizations reveal their fascinating SMM properties with high energy barriers as 472(7) K for 1 and 543(2) K for 2, along with a record magnetic hysteresis temperature up to 20 K for 2. These results, combined with the ab initio calculations, offer an illuminating insight into the vast possibility and potential of what the symmetry rules can achieve in molecular magnetism. PMID:26883386

  17. Symmetry-Supported Magnetic Blocking at 20 K in Pentagonal Bipyramidal Dy(III) Single-Ion Magnets.

    PubMed

    Chen, Yan-Cong; Liu, Jun-Liang; Ungur, Liviu; Liu, Jiang; Li, Quan-Wen; Wang, Long-Fei; Ni, Zhao-Ping; Chibotaru, Liviu F; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-03-01

    Single-molecule magnets (SMMs) that can be trapped in one of the bistable magnetic states separated by an energy barrier are among the most promising candidates for high-density information storage, quantum processing, and spintronics. To date, a considerable series of achievements have been made. However, the presence of fast quantum tunnelling of magnetization (QTM) in most SMMs, especially in single-ion magnets (SIMs), provides a rapid relaxation route and often sets up a limit for the relaxation time. Here, we pursue the pentagonal bipyramidal symmetry to suppress the QTM and present pentagonal bipyramidal Dy(III) SIMs [Dy(Cy3PO)2(H2O)5]Cl3·(Cy3PO)·H2O·EtOH (1) and [Dy(Cy3PO)2(H2O)5]Br3·2(Cy3PO)·2H2O·2EtOH (2), (Cy3PO = tricyclohexyl phosphine oxide). Magnetic characterizations reveal their fascinating SMM properties with high energy barriers as 472(7) K for 1 and 543(2) K for 2, along with a record magnetic hysteresis temperature up to 20 K for 2. These results, combined with the ab initio calculations, offer an illuminating insight into the vast possibility and potential of what the symmetry rules can achieve in molecular magnetism.

  18. Schwarzschild black holes can wear scalar wigs.

    PubMed

    Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier

    2012-08-24

    We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.

  19. Schwarzschild Black Holes can Wear Scalar Wigs

    NASA Astrophysics Data System (ADS)

    Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier

    2012-08-01

    We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.

  20. Scalar and Pseudoscalar Glueballs Revisited

    SciTech Connect

    Cheng Haiyang

    2010-08-05

    Using two simple and robust inputs to constrain the mixing matrix of the isosinglet scalar mesons f{sub 0}(1710), f{sub 0}(1500), f{sub 0}(1370), we have shown that in the SU(3) symmetry limit, f{sub 0}(1500) becomes apure SU(3) octet and is degenerate with a{sub 0}(1450), while f{sub 0}(1370) is mainly an SU(3) singlet with a slight mixing with the scalar glueball which is the primary component of f{sub 0}(1710). These features remain essentially unchanged even when SU(3) breaking is taken into account. We have deduced the mass of the pseudoscalar glueball G from an {eta}-{eta}{sup '}-G mixing formalism based on the anomalous Ward identity for transition matrix elements. With the inputs from the recent KLOE experiment, we found a solution for the pseudoscalar glueball mass around (1.4{+-}0.1) GeV. This affirms that 77 (1405), having a large production rate in the radiative J/{Psi} decay and not seen in {gamma}{gamma} reactions, is indeed a leading candidate for the pseudoscalar glueball. It is much lower than the results from quenched lattice QCD (> 2.0 GeV).

  1. Analysis of Doppler Lidar Data Acquired During the Pentagon Shield Field Campaign

    SciTech Connect

    Newsom, Rob K.

    2011-04-14

    Observations from two coherent Doppler lidars deployed during the Pentagon Shield field campaign are analyzed in conjunction with other sensors to characterize the overall boundary-layer structure, and identify the dominant flow characteristics during the entire two-week field campaign. Convective boundary layer (CBL) heights and cloud base heights (CBH) are estimated from an analysis of the lidar signal-to-noise-ratio (SNR), and mean wind profiles are computed using a modified velocity-azimuth-display (VAD) algorithm. Three-dimensional wind field retrievals are computed from coordinated overlapping volume scans, and the results are analyzed by visualizing the flow in horizontal and vertical cross sections. The VAD winds show that southerly flows dominate during the two-week field campaign. Low-level jets (LLJ) were evident on all but two of the nights during the field campaign. The LLJs tended to form a couple hours after sunset and reach maximum strength between 03 and 07 UTC. The surface friction velocities show distinct local maxima during four nights when strong LLJs formed. Estimates of the convective boundary layer height and residual layer height are obtained through an analysis of the vertical gradient of the lidar signal-to-noise-ratio (SNR). Strong minimum in the SNR gradient often develops just above the surface after sunrise. This minimum is associated with the developing CBL, and increases rapidly during the early portion of the daytime period. On several days, this minimum continues to increase until about sunset. Secondary minima in the SNR gradient were also observed at higher altitudes, and are believed to be remnants of the CBL height from previous days, i.e. the residual layer height. The dual-Doppler analysis technique used in this study makes use of hourly averaged radial velocity data to produce three-dimensional grids of the horizontal velocity components, and the horizontal velocity variance. Visualization of horizontal and vertical cross

  2. One-loop nonlinear correction for QED

    NASA Astrophysics Data System (ADS)

    Furtado, J. S. N.; Silva, G. R.

    2016-08-01

    In this work, we study the generation of a nonlinear correction for QED, namely, the Euler-Heisenberg effective action. In order to achieve this, we consider two methods. The first method employed consists in make use of Feynman parametrization to solve the integrals properly, while in the second method a derivative expansion in the external momentum was considered.

  3. Vacuum fluctuations of a scalar field during inflation: Quantum versus stochastic analysis

    NASA Astrophysics Data System (ADS)

    Onemli, V. K.

    2015-05-01

    We consider an infrared truncated massless minimally coupled scalar field with a quartic self-interaction in the locally de Sitter background of an inflating universe. We compute the two-point correlation function of the scalar at one- and two-loop order applying quantum field theory. The tree-order correlator at a fixed comoving separation (that is at an increasing physical distance) freezes into a nonzero value. At a fixed physical distance, it grows linearly with the comoving time. The one-loop correlator, which is the dominant quantum correction, implies a negative temporal growth in the correlation function, at this order, at a fixed comoving separation and at a fixed physical distance. We also obtain quantitative results for variance in space and time of one- and two-loop correlators and infer that the contrast between the vacuum expectation value and the variance becomes less pronounced when the loop corrections are included. Finally, we repeat the analysis of the model applying a stochastic field theory and reach the same conclusions.

  4. Naturalness in a type II seesaw model and implications for physical scalars

    NASA Astrophysics Data System (ADS)

    Chabab, M.; Peyranère, M. C.; Rahili, L.

    2016-06-01

    In this paper, we consider a minimal extension to the standard model by a scalar triplet field with hypercharge Y =2 . This model relies on the seesaw mechanism which provides a consistent explication of neutrino mass generation. We show from naturalness considerations that the Veltman condition is modified by virtue of the additional scalar charged states and that quadratic divergencies at one loop can be driven to zero within the allowed parameter space of the model; the latter is severely constrained by unitarity and boundedness from below, and it is consistent with the di-photon Higgs decay data of the LHC. Furthermore, we analyze the naturalness condition effects to the masses of heavy Higgs bosons H0, A0, H± and H±±, providing a drastic reduction of the ranges of variation of mH± and mH±± with an upper bounds at 288 and 351 GeV, respectively, while predicting almost a degeneracy for the other neutral Higgs bosons H0, A0 at about 207 GeV.

  5. Scalar Mesons and Chiral States

    NASA Astrophysics Data System (ADS)

    Ishida, M.; Ishida, S.

    2004-08-01

    The essential points and physical backgrounds of the covariant level-classification scheme, based on Ū(12)SF⊗O(3, 1)L, are reviewed: This scheme is extended from the non-relativistic SU(6)SF⊗O(3)L scheme by introducing the new SU(2)-spin (ρ-spin) degree of freedom, which is necessary for covariant description of composite hadrons. Our scheme predicts the existence of new type of chiral mesons and baryons (Chiralons) out of the conventional SU(6)SF⊗O(3)L scheme. The σ nonet is a typical example of chiralons to be assigned to the (qq¯) relativistic S-wave state. The new narrow mesons Ds(2317)/Ds(2463) are naturally assigned as the ground-state scalar and axial-vector chiralons in the (cs¯) system.

  6. Cross Sections From Scalar Field Theory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank; Norman, Ryan B.; Nasto, Rachel

    2008-01-01

    A one pion exchange scalar model is used to calculate differential and total cross sections for pion production through nucleon- nucleon collisions. The collisions involve intermediate delta particle production and decay to nucleons and a pion. The model provides the basic theoretical framework for scalar field theory and can be applied to particle production processes where the effects of spin can be neglected.

  7. A note on perfect scalar fields

    NASA Astrophysics Data System (ADS)

    Unnikrishnan, Sanil; Sriramkumar, L.

    2010-05-01

    We derive a condition on the Lagrangian density describing a generic, single, noncanonical scalar field, by demanding that the intrinsic, nonadiabatic pressure perturbation associated with the scalar field vanishes identically. Based on the analogy with perfect fluids, we refer to such fields as perfect scalar fields. It is common knowledge that models that depend only on the kinetic energy of the scalar field (often referred to as pure kinetic models) possess no nonadiabatic pressure perturbation. While we are able to construct models that seemingly depend on the scalar field and also do not contain any nonadiabatic pressure perturbation, we find that all such models that we construct allow a redefinition of the field under which they reduce to pure kinetic models. We show that, if a perfect scalar field drives inflation, then, in such situations, the first slow roll parameter will always be a monotonically decreasing function of time. We point out that this behavior implies that these scalar fields cannot lead to features in the inflationary, scalar perturbation spectrum.

  8. Psycholinguistic and Neurolinguistic Investigations of Scalar Implicature

    ERIC Educational Resources Information Center

    Politzer-Ahles, Stephen

    2013-01-01

    The present study examines the representation and composition of meaning in scalar implicatures. Scalar implicature is the phenomenon whereby the use of a less informative term (e.g., "some") is inferred to mean the negation of a more informative term (e.g., to mean "not all"). The experiments reported here investigate how the…

  9. Scalar gain interpretation of large order filters

    NASA Technical Reports Server (NTRS)

    Mason, Paul A. C.; Mook, D. Joseph

    1993-01-01

    A technique is developed which demonstrates how to interpret a large fully-populated filter gain matrix as a set of scalar gains. The inverse problem is also solved, namely, how to develop a large-order filter gain matrix from a specified set of scalar gains. Examples are given to illustrate the method.

  10. Scalar Fields via Causal Tapestries

    NASA Astrophysics Data System (ADS)

    Sulis, William

    2012-02-01

    Causal tapestries provide a framework for implementing an explicit Process Theory approach to quantum foundations which models information flow within a physical system. We consider event-transition tapestry pairs. An event tapestry O is a 4-tuple (L, K, M, Ip ) where K is an index set of cardinality κ, M = M x F(M) x D x P(M') a mathematical structure with M a causal space, F(M) a function space, D a descriptor space, P(M') either a Lie algebra or tangent space on a manifold M', Ip an event tapestry. L consists of elements of the form [n]<α>G, n in K, α in M and G an acyclic directed graph whose vertex set is a subset of Lp Likewise, a transition tapestry π is a 4-tuple (L', K', M', I'p ) where M' = M' x F(M') x D' x P'(M). The dynamic generates a consistent succession of O-π pairs by means of a game based on the technique of forcing used in logic to generate models. This dynamic has previously been shown to be compatible with Lorentz invariance. An application of this approach to model scalar fields is presented in which each informon is associated with a function of the form f(πk1 /σ1 ,,πkN /σN )sin ( σ1 t1 --πk1 )/ ( σ1 t1 --πk1 ) .sin ( σN tN --πkN )/ ( σN tN --πkN ) and the WSK interpolation theorem is used to generate the resulting scalar field on the causal manifold.

  11. A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K.

    PubMed

    Liu, Jiang; Chen, Yan-Cong; Liu, Jun-Liang; Vieru, Veacheslav; Ungur, Liviu; Jia, Jian-Hua; Chibotaru, Liviu F; Lan, Yanhua; Wernsdorfer, Wolfgang; Gao, Song; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-04-27

    Single-molecule magnets (SMMs) with a large spin reversal barrier have been recognized to exhibit slow magnetic relaxation that can lead to a magnetic hysteresis loop. Synthesis of highly stable SMMs with both large energy barriers and significantly slow relaxation times is challenging. Here, we report two highly stable and neutral Dy(III) classical coordination compounds with pentagonal bipyramidal local geometry that exhibit SMM behavior. Weak intermolecular interactions in the undiluted single crystals are first observed for mononuclear lanthanide SMMs by micro-SQUID measurements. The investigation of magnetic relaxation reveals the thermally activated quantum tunneling of magnetization through the third excited Kramers doublet, owing to the increased axial magnetic anisotropy and weaker transverse magnetic anisotropy. As a result, pronounced magnetic hysteresis loops up to 14 K are observed, and the effective energy barrier (Ueff = 1025 K) for relaxation of magnetization reached a breakthrough among the SMMs. PMID:27054904

  12. A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K.

    PubMed

    Liu, Jiang; Chen, Yan-Cong; Liu, Jun-Liang; Vieru, Veacheslav; Ungur, Liviu; Jia, Jian-Hua; Chibotaru, Liviu F; Lan, Yanhua; Wernsdorfer, Wolfgang; Gao, Song; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-04-27

    Single-molecule magnets (SMMs) with a large spin reversal barrier have been recognized to exhibit slow magnetic relaxation that can lead to a magnetic hysteresis loop. Synthesis of highly stable SMMs with both large energy barriers and significantly slow relaxation times is challenging. Here, we report two highly stable and neutral Dy(III) classical coordination compounds with pentagonal bipyramidal local geometry that exhibit SMM behavior. Weak intermolecular interactions in the undiluted single crystals are first observed for mononuclear lanthanide SMMs by micro-SQUID measurements. The investigation of magnetic relaxation reveals the thermally activated quantum tunneling of magnetization through the third excited Kramers doublet, owing to the increased axial magnetic anisotropy and weaker transverse magnetic anisotropy. As a result, pronounced magnetic hysteresis loops up to 14 K are observed, and the effective energy barrier (Ueff = 1025 K) for relaxation of magnetization reached a breakthrough among the SMMs.

  13. Fused Dibenzo[a,m]rubicene: A New Bowl-Shaped Subunit of C70 Containing Two Pentagons.

    PubMed

    Liu, Junzhi; Osella, Silvio; Ma, Ji; Berger, Reinhard; Beljonne, David; Schollmeyer, Dieter; Feng, Xinliang; Müllen, Klaus

    2016-07-13

    Total synthetic approaches of fullerenes are the holy grail for organic chemistry. So far, the main attempts have focused on the synthesis of the buckminsterfullerene C60. In contrast, access to subunits of the homologue C70 remains challenging. Here, we demonstrate an efficient bottom-up strategy toward a novel bowl-shaped polycyclic aromatic hydrocarbons (PAH) C34 with two pentagons. This PAH represents a subunit for C70 and of other higher fullerenes. The bowl-shaped structure was unambiguously determined by X-ray crystallography. A bowl-to-bowl inversion for a C70 fragment in solution was investigated by dynamic NMR analysis, showing a bowl-to-bowl inversion energy (ΔG(⧧)) of 16.7 kcal mol(-1), which is further corroborated by DFT calculations. PMID:27355697

  14. High-level ab-initio calculations for the four low-lying families of minima of (H2O)20: II. Spectroscopic signatures of the dodecahedron, fused cubes, face-sharing pentagonal prisms, and edge-sharing pentagonal prisms hydrogen bonding networks

    SciTech Connect

    Fanourgakis, Georgios S.; Apra, Edoardo; De Jong, Wibe A.; Xantheas, Sotiris S.

    2005-04-01

    We report the first harmonic vibrational spectra for each of the lowest lying isomers within the four major families of minima of (H{sub 2}O){sub 20}, namely the dodecahedron, fused cubes, face-sharing pentagonal prisms and edge-sharing pentagonal prisms. These were obtained at the second-order Moeller-Plesset perturbation level of theory (MP2) with the augmented correlation consistent basis set of double zeta quality (aug-cc-pVDZ) at the corresponding minimum energy geometries. The computed infrared (IR) spectra are the first ones obtained from first principles for these clusters. They were found to contain spectral features, which can be directly mapped onto the distinctive spectroscopic signatures of their constituent tetramer, pentamer and octamer fragments. The dodecahedron spectra show the richest structure in the OH stretching region and are associated with the most red-shifted OH vibrations with respect to the monomer. The lowest lying face-sharing pentagonal prism isomer displays intense IR active vibrations that are red-shifted by {approx}600 cm{sup -1} with respect to the water monomer. The zero-point energy corrected MP2/CBS (complete basis set) limit binding energies (D{sub 0}) for the four isomers are -163.1 kcal/mol (face-sharing pentagonal prism), -160.1 kcal/mol (edgesharing pentagonal prism), -157.5 kcal/mol (fused cubes) and -148.1 kcal/mol (dodecahedron).

  15. Viable dark matter via radiative symmetry breaking in a scalar singlet Higgs portal extension of the standard model.

    PubMed

    Steele, T G; Wang, Zhi-Wei; Contreras, D; Mann, R B

    2014-05-01

    We consider the generation of dark matter mass via radiative electroweak symmetry breaking in an extension of the conformal standard model containing a singlet scalar field with a Higgs portal interaction. Generating the mass from a sequential process of radiative electroweak symmetry breaking followed by a conventional Higgs mechanism can account for less than 35% of the cosmological dark matter abundance for dark matter mass M(s)>80 GeV. However, in a dynamical approach where both Higgs and scalar singlet masses are generated via radiative electroweak symmetry breaking, we obtain much higher levels of dark matter abundance. At one-loop level we find abundances of 10%-100% with 106 GeVscalar-singlet self-coupling, providing a natural explanation for the astrophysical observations that place upper bounds on dark matter self-interaction. The predictions in all three approaches are within the M(s)>80 GeV detection region of the next generation XENON experiment.

  16. Regulating the infrared by mode matching: A massless scalar in expanding spaces with constant deceleration

    SciTech Connect

    Janssen, T. M.; Prokopec, T.

    2011-04-15

    In this paper we consider a massless scalar field, with a possible coupling {xi} to the Ricci scalar in a D dimensional Friedmann-Lemaitre-Robertson-Walker space-time with a constant deceleration parameter q={epsilon}-1, {epsilon}=-H/H{sup 2}. Correlation functions for the Bunch-Davies vacuum of such a theory have long been known to be infrared divergent for a wide range of values of {epsilon}. We resolve these divergences by explicitly matching the space-time under consideration to a space-time without infrared divergencies. Such a procedure ensures that all correlation functions with respect to the vacuum in the space-time of interest are infrared finite. In this newly defined vacuum we construct the coincidence limit of the propagator and as an example calculate the expectation value of the stress-energy tensor. We find that this approach gives both in the ultraviolet and in the infrared satisfactory results. Moreover, we find that, unless the effective mass due to the coupling to the Ricci scalar {xi}R is negative, quantum contributions to the energy density always dilute away faster, or just as fast, as the background energy density. Therefore, quantum backreaction is insignificant at the one-loop order, unless {xi}R is negative. Finally we compare this approach with known results where the infrared is regulated by placing the Universe in a finite box. In an accelerating universe, the results are qualitatively the same, provided one identifies the size of the Universe with the physical Hubble radius at the time of the matching. In a decelerating universe, however, the two schemes give different late time behavior for the quantum stress-energy tensor. This happens because in this case the length scale at which one regulates the infrared becomes sub-Hubble at late times.

  17. Static weak dipole moments of the τ lepton via renormalizable scalar leptoquark interactions

    NASA Astrophysics Data System (ADS)

    Bolaños, A.; Moyotl, A.; Tavares-Velasco, G.

    2014-03-01

    The weak dipole moments of elementary fermions are calculated at the one-loop level in the framework of a renormalizable scalar leptoquark model that forbids baryon number violating processes and so is free from the strong constraints arising from experimental data. In this model there are two scalar leptoquarks accommodated in a SUL(2)×UY(1) doublet: One of these leptoquarks is nonchiral and has electric charge of 5/3e, whereas the other one is chiral and has electric charge 2/3e. In particular, a nonchiral leptoquark contributes to the weak properties of an up fermion via a chirality-flipping term proportional to the mass of the virtual fermion, and can also induce a nonzero weak electric dipole moment provided that the leptoquark couplings are complex. The numerical analysis is focused on the weak properties of the τ lepton since they offer good prospects for experimental study. The constraints on leptoquark couplings are briefly discussed for a nonchiral leptoquark with nondiagonal couplings to the second and third fermion generations, a third-generation nonchiral leptoquark, and a third-generation chiral leptoquark. It is found that although the chirality-flipping term can enhance the weak properties of the τ lepton via the top quark contribution, such an enhancement would be offset by the strong constraints on the leptoquark couplings. So, the contribution of scalar leptoquarks to the weak magnetic dipole moment of the τ lepton are smaller than the standard model (SM) contributions but can be of similar size to those arising in some SM extensions. A nonchiral leptoquark can also give contributions to the weak electric dipole moment larger than the SM one but well below the experimental limit. We also discuss the case of the off-shell weak dipole moments and, for completeness, analyze the behavior of the τ electromagnetic properties.

  18. Refining inflation using non-canonical scalars

    SciTech Connect

    Unnikrishnan, Sanil; Sahni, Varun; Toporensky, Aleksey E-mail: varun@iucaa.ernet.in

    2012-08-01

    This paper revisits the Inflationary scenario within the framework of scalar field models possessing a non-canonical kinetic term. We obtain closed form solutions for all essential quantities associated with chaotic inflation including slow roll parameters, scalar and tensor power spectra, spectral indices, the tensor-to-scalar ratio, etc. We also examine the Hamilton-Jacobi equation and demonstrate the existence of an inflationary attractor. Our results highlight the fact that non-canonical scalars can significantly improve the viability of inflationary models. They accomplish this by decreasing the tensor-to-scalar ratio while simultaneously increasing the value of the scalar spectral index, thereby redeeming models which are incompatible with the cosmic microwave background (CMB) in their canonical version. For instance, the non-canonical version of the chaotic inflationary potential, V(φ) ∼ λφ{sup 4}, is found to agree with observations for values of λ as large as unity! The exponential potential can also provide a reasonable fit to CMB observations. A central result of this paper is that steep potentials (such as V∝φ{sup −n}) usually associated with dark energy, can drive inflation in the non-canonical setting. Interestingly, non-canonical scalars violate the consistency relation r = −8n{sub T}, which emerges as a smoking gun test for this class of models.

  19. Scalar Mixing In A Vortex Flow

    NASA Astrophysics Data System (ADS)

    Meunier, P.; Villermaux, E.; Leweke, T.

    We present experimental and theoretical results on the evolution of a scalar blob em- bedded in the velocity field of one or two vortices, a configuration relevant to geo- physical mixing in particular. We first follow the evolution of the scalar in one vortex. The scalar blob rolls up into a spiral and then diffuses rapidly, much faster than in the absence of a vortex flow. A simple model predicts that the maximal scalar concentration decreases in time as t-3 , after a mixing time which scales like Pe1 /2 /3 (where Pe = /D is the Peclet number). This hyper-diffusion process is due to the coupled presence of stretching and diffusion, and is in good quantitative agreement with the experimental results. In contrast with this temporal variation of the scalar, the model predicts that the proba- bility distribution functions (PDF) of the scalar are almost stationnary. The agreement between experimental and theoretical PDF is excellent. Finally, we report on the evolution of the PDF of a scalar during the merging of two vortices and on the comparison law of the concentration PDF's associated with each vortices, both in laminar and turbulent situations.

  20. Oscillons in dilaton-scalar theories

    NASA Astrophysics Data System (ADS)

    Fodor, Gyula; Forgács, Péter; Horváth, Zalán; Mezei, Márk

    2009-08-01

    It is shown by both analytical methods and numerical simulations that extremely long living spherically symmetric oscillons appear in virtually any real scalar field theory coupled to a massless dilaton (DS theories). In fact such ``dilatonic'' oscillons are already present in the simplest non-trivial DS theory — a free massive scalar field coupled to the dilaton. It is shown that in analogy to the previously considered cases with a single nonlinear scalar field, in DS theories there are also time periodic quasibreathers (QB) associated to small amplitude oscillons. Exploiting the QB picture the radiation law of the small amplitude dilatonic oscillons is determined analytically.

  1. Electrophobic Scalar Boson and Muonic Puzzles

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Sheng; McKeen, David; Miller, Gerald A.

    2016-09-01

    A new scalar boson which couples to the muon and proton can simultaneously solve the proton radius puzzle and the muon anomalous magnetic moment discrepancy. Using a variety of measurements, we constrain the mass of this scalar and its couplings to the electron, muon, neutron, and proton. Making no assumptions about the underlying model, these constraints and the requirement that it solve both problems limit the mass of the scalar to between about 100 keV and 100 MeV. We identify two unexplored regions in the coupling constant-mass plane. Potential future experiments and their implications for theories with mass-weighted lepton couplings are discussed.

  2. Static scalar field solutions in symmetric gravity

    NASA Astrophysics Data System (ADS)

    Hossenfelder, S.

    2016-09-01

    We study an extension of general relativity with a second metric and an exchange symmetry between the two metrics. Such an extension might help to address some of the outstanding problems with general relativity, for example the smallness of the cosmological constant. We here derive a family of exact solutions for this theory. In this two-parameter family of solutions the gravitational field is sourced by a time-independent massless scalar field. We find that the only limit in which the scalar field entirely vanishes is flat space. The regular Schwarzschild-solution is left with a scalar field hidden in the second metric’s sector.

  3. Beyond the Standard Model: Scalar dark matter, and, lepton flavor violation

    NASA Astrophysics Data System (ADS)

    Gonderinger, Matthew

    The Standard Model of particle physics is a highly successful theory of fundamental particle interactions, especially in light of the recent discovery of a Higgs-like boson at the LHC. Nonetheless, the SM is incomplete, and the search for physics beyond the SM has prompted a great amount of experimental and theoretical work. In this thesis, I present theoretical work I have done in two areas of beyond the SM physics: scalar dark matter and lepton flavor violation. Scalar extensions of the SM are simple but nonetheless interesting and well-motivated models for beyond the SM physics that can include a dark matter candidate particle. Using the renormalization group evolution of the model parameters and the Coleman-Weinberg one-loop effective potential, I perform an analysis of the vacuum stability of two of these scalar extensions, the real singlet and the complex singlet. Also included are experimental bounds from dark matter direct detection. The vacuum stability analysis reveals that light dark matter (10 GeV) requires a moderate self-interaction strength and new physics at or below the 109 GeV scale in the case of the real scalar, and a light (order 10 to 100 GeV) Higgs-like particle with reduced couplings and additional new physics below 1000 TeV in the case of the complex scalar. Lepton flavor violation probes the high energy scale of new physics through its effects on low energy processes which are highly suppressed in the SM by small neutrino masses. I utilize the Buchmuller-Ruckl-Wyler parameterization of leptoquarks and limits obtained from the HERA experiments ZEUS and H1 to calculate the cross section for electron-to-tau conversion in DIS at a next generation Electron-Ion Collider (EIC) with high luminosity. The potential for the EIC to search for such events is compared with the ability of future tau → egamma searches to set limits on leptoquark masses and couplings. This analysis demonstrates that a future EIC search would be competitive with or

  4. Searching for the Scalar Glueball

    SciTech Connect

    Ochs, Wolfgang

    2008-08-31

    Existence of gluonic resonances is among the early expectations of QCD. Today, QCD calculations predict the lightest glueball to be a scalar state with mass within a range of about 900-1700 MeV but there is no consensus about its experimental evidence. In a re-analysis of the phase shifts for {pi}{pi} scattering up to 1800 MeV where such states should show up we find the broad resonance f{sub 0}(600)/{sigma} contributing to the full mass range and the narrow f{sub 0}(980) and f{sub 0}(1500) but no evidence for f{sub 0}(1370). Phenomenological arguments for the broad state to be a glueball are recalled. It is argued that the large radiative width of f{sub 0}(600)/{sigma} reported recently is not in contradiction to this hypothesis but is mainly due to {pi}{pi}-rescattering. The small 'direct' radiative component is consistent with QCD sum rule predictions for the light glueball.

  5. Diphoton decay for a 750 GeV scalar boson in a SU(6)⊗U(1)X model

    NASA Astrophysics Data System (ADS)

    Mantilla, S. F.; Martinez, R.; Ochoa, F.; Sierra, C. F.

    2016-10-01

    We propose a new SU (6) ⊗ U(1)X GUT model free from anomalies, with a 750 GeV scalar candidate which can decay into two photons, compatible with the recent diphoton signal reported by ATLAS and CMS collaborations. This model gives masses to all fermions and may explain the 750 GeV signal through one loop decays to γγ with charged vector and charged Higgs bosons, as well as up- and electron-like exotic particles that arise naturally from the condition of cancellation of anomalies of the SU (6) ⊗ U(1)X group. We obtain, for different width approximations, allowed mass regions from 900 GeV to 3 TeV for the exotic up-like quark, in agreement with ATLAS and CMS collaborations data.

  6. Inflation in anisotropic scalar-tensor theories

    NASA Technical Reports Server (NTRS)

    Pimentel, Luis O.; Stein-Schabes, Jaime

    1988-01-01

    The existence of an inflationary phase in anisotropic Scalar-Tensor Theories is investigated by means of a conformal transformation that allows us to rewrite these theories as gravity minimally coupled to a scalar field with a nontrivial potential. The explicit form of the potential is then used and the No Hair Theorem concludes that there is an inflationary phase in all open or flat anisotropic spacetimes in these theories. Several examples are constructed where the effect becomes manifest.

  7. Stability of a collapsed scalar field and cosmic censorship

    SciTech Connect

    Abe, S.

    1988-08-15

    The static and asymptotically flat solution to the Einstein-massless-scalar model with spherical symmetry describes the spacetime with a naked singularity when it has a nonvanishing scalar charge. We show that such a solution is unstable against the spherical scalar monopole perturbation. This suggests the validity of the cosmic censorship hypothesis in the spherical collapse of the scalar field.

  8. Isolated pentagon rule violating endohedral metallofullerenes explained using the Hückel rule: a statistical mechanical study of the C84 Isomeric Set.

    PubMed

    Fuhrer, Timothy J; Lambert, Angel M

    2015-01-30

    Fullerenes and their structure and stability have been a major topic of discussion and research since their discovery nearly 30 years ago. The isolated pentagon rule (IPR) has long served as a guideline for predicting the most stable fullerene cages. More recently, endohedral metallofullerenes have been discovered that violate the IPR. This article presents a systematic, temperature dependent, statistical thermodynamic study of the 24 possible IPR isomers of C84 as well as two of the experimentally known non-IPR isomers (51365 and 51383), at several different charges (0, -2, -4, and -6). From the results of this study, we conclude that the Hückel rule is a valid simpler explanation for the stability of fused pentagons in endohedral metallofullerenes.

  9. First-principles theory of Si(110)-(16 × 2) surface reconstruction for unveiling origin of pentagonal scanning tunneling microscopy images

    NASA Astrophysics Data System (ADS)

    Yamasaki, Takahiro; Kato, Koichi; Uda, Tsuyoshi; Yamamoto, Takenori; Ohno, Takahisa

    2016-03-01

    The origin of the scanning tunneling microscopy (STM) zigzag chain structures composed of pairs of pentagons on the Si(110)-(16 × 2) surface is unveiled through the first-principles calculation method. Stable Si(110) surface structures, on both flat and stepped surfaces, have been discovered. The energy gain of the stable step structure is larger than those of previously proposed models by 5.0 eV/(16 × 2) cell or more. The structure consists of buckled tetramers, heptagonal rings, tetragonal rings, and threefold-coordinated Si atoms, but no pentagonal rings. It reproduces the experimental STM images only when frequent flip-floppings of the buckled tetramers at room temperature are considered.

  10. GaN nanowires with pentagon shape cross-section by ammonia-source molecular beam epitaxy

    DOE PAGES

    Lin, Yong; Leung, Benjamin; Li, Qiming; Figiel, Jeffrey J.; Wang, George T.

    2015-07-14

    In this study, ammonia-based molecular beam epitaxy (NH3-MBE) was used to grow catalyst-assisted GaN nanowires on (11¯02) r-plane sapphire substrates. Dislocation free [112¯0] oriented nanowires are formed with pentagon shape cross-section, instead of the usual triangular shape facet configuration. Specifically, the cross-section is the result of the additional two nonpolar {101¯0} side facets, which appear due to a decrease in relative growth rate of the {101¯0} facets to the {101¯1} and {101¯1} facets under the growth regime in NH3-MBE. Compared to GaN nanowires grown by Ni-catalyzed metal–organic chemical vapor deposition, the NH3-MBE grown GaN nanowires show more than an ordermore » of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.« less

  11. GaN nanowires with pentagon shape cross-section by ammonia-source molecular beam epitaxy

    SciTech Connect

    Lin, Yong; Leung, Benjamin; Li, Qiming; Figiel, Jeffrey J.; Wang, George T.

    2015-07-14

    In this study, ammonia-based molecular beam epitaxy (NH3-MBE) was used to grow catalyst-assisted GaN nanowires on (11¯02) r-plane sapphire substrates. Dislocation free [112¯0] oriented nanowires are formed with pentagon shape cross-section, instead of the usual triangular shape facet configuration. Specifically, the cross-section is the result of the additional two nonpolar {101¯0} side facets, which appear due to a decrease in relative growth rate of the {101¯0} facets to the {101¯1} and {101¯1} facets under the growth regime in NH3-MBE. Compared to GaN nanowires grown by Ni-catalyzed metal–organic chemical vapor deposition, the NH3-MBE grown GaN nanowires show more than an order of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.

  12. Dpp Signaling Activity Requires Pentagone to Scale with Tissue Size in the Growing Drosophila Wing Imaginal Disc

    PubMed Central

    Pyrowolakis, George; Bergmann, Sven; Affolter, Markus

    2011-01-01

    The wing of the fruit fly, Drosophila melanogaster, with its simple, two-dimensional structure, is a model organ well suited for a systems biology approach. The wing arises from an epithelial sac referred to as the wing imaginal disc, which undergoes a phase of massive growth and concomitant patterning during larval stages. The Decapentaplegic (Dpp) morphogen plays a central role in wing formation with its ability to co-coordinately regulate patterning and growth. Here, we asked whether the Dpp signaling activity scales, i.e. expands proportionally, with the growing wing imaginal disc. Using new methods for spatial and temporal quantification of Dpp activity and its scaling properties, we found that the Dpp response scales with the size of the growing tissue. Notably, scaling is not perfect at all positions in the field and the scaling of target gene domains is ensured specifically where they define vein positions. We also found that the target gene domains are not defined at constant concentration thresholds of the downstream Dpp activity gradients P-Mad and Brinker. Most interestingly, Pentagone, an important secreted feedback regulator of the pathway, plays a central role in scaling and acts as an expander of the Dpp gradient during disc growth. PMID:22039350

  13. Dpp signaling activity requires Pentagone to scale with tissue size in the growing Drosophila wing imaginal disc.

    PubMed

    Hamaratoglu, Fisun; de Lachapelle, Aitana Morton; Pyrowolakis, George; Bergmann, Sven; Affolter, Markus

    2011-10-01

    The wing of the fruit fly, Drosophila melanogaster, with its simple, two-dimensional structure, is a model organ well suited for a systems biology approach. The wing arises from an epithelial sac referred to as the wing imaginal disc, which undergoes a phase of massive growth and concomitant patterning during larval stages. The Decapentaplegic (Dpp) morphogen plays a central role in wing formation with its ability to co-coordinately regulate patterning and growth. Here, we asked whether the Dpp signaling activity scales, i.e. expands proportionally, with the growing wing imaginal disc. Using new methods for spatial and temporal quantification of Dpp activity and its scaling properties, we found that the Dpp response scales with the size of the growing tissue. Notably, scaling is not perfect at all positions in the field and the scaling of target gene domains is ensured specifically where they define vein positions. We also found that the target gene domains are not defined at constant concentration thresholds of the downstream Dpp activity gradients P-Mad and Brinker. Most interestingly, Pentagone, an important secreted feedback regulator of the pathway, plays a central role in scaling and acts as an expander of the Dpp gradient during disc growth.

  14. Releasing scalar fields: cosmological simulations of scalar-tensor theories for gravity beyond the static approximation.

    PubMed

    Llinares, Claudio; Mota, David F

    2013-04-19

    Several extensions of general relativity and high energy physics include scalar fields as extra degrees of freedom. In the search for predictions in the nonlinear regime of cosmological evolution, the community makes use of numerical simulations in which the quasistatic limit is assumed when solving the equation of motion of the scalar field. In this Letter, we propose a method to solve the full equations of motion for scalar degrees of freedom coupled to matter. We run cosmological simulations which track the full time and space evolution of the scalar field, and find striking differences with respect to the commonly used quasistatic approximation. This novel procedure reveals new physical properties of the scalar field and uncovers concealed astrophysical phenomena which were hidden in the old approach. PMID:23679591

  15. Can dark matter be a scalar field?

    NASA Astrophysics Data System (ADS)

    Jesus, J. F.; Pereira, S. H.; Malatrasi, J. L. G.; Andrade-Oliveira, F.

    2016-08-01

    In this paper we study a real scalar field as a possible candidate to explain the dark matter in the universe. In the context of a free scalar field with quadratic potential, we have used Union 2.1 SN Ia observational data jointly with a Planck prior over the dark matter density parameter to set a lower limit on the dark matter mass as m>=0.12H0‑1 eV (c=hbar=1). For the recent value of the Hubble constant indicated by the Hubble Space Telescope, namely H0=73±1.8 km s‑1Mpc‑1, this leads to m>=1.56×10‑33 eV at 99.7% c.l. Such value is much smaller than m~ 10‑22 eV previously estimated for some models. Nevertheless, it is still in agreement with them once we have not found evidences for a upper limit on the scalar field dark matter mass from SN Ia analysis. In practice, it confirms free real scalar field as a viable candidate for dark matter in agreement with previous studies in the context of density perturbations, which include scalar field self interaction.

  16. Can dark matter be a scalar field?

    NASA Astrophysics Data System (ADS)

    Jesus, J. F.; Pereira, S. H.; Malatrasi, J. L. G.; Andrade-Oliveira, F.

    2016-08-01

    In this paper we study a real scalar field as a possible candidate to explain the dark matter in the universe. In the context of a free scalar field with quadratic potential, we have used Union 2.1 SN Ia observational data jointly with a Planck prior over the dark matter density parameter to set a lower limit on the dark matter mass as m>=0.12H0-1 eV (c=hbar=1). For the recent value of the Hubble constant indicated by the Hubble Space Telescope, namely H0=73±1.8 km s-1Mpc-1, this leads to m>=1.56×10-33 eV at 99.7% c.l. Such value is much smaller than m~ 10-22 eV previously estimated for some models. Nevertheless, it is still in agreement with them once we have not found evidences for a upper limit on the scalar field dark matter mass from SN Ia analysis. In practice, it confirms free real scalar field as a viable candidate for dark matter in agreement with previous studies in the context of density perturbations, which include scalar field self interaction.

  17. Inflation as AN Attractor in Scalar Cosmology

    NASA Astrophysics Data System (ADS)

    Kim, Hyeong-Chan

    2013-06-01

    We study an inflation mechanism based on attractor properties in cosmological evolutions of a spatially flat Friedmann-Robertson-Walker spacetime based on the Einstein-scalar field theory. We find a new way to get the Hamilton-Jacobi equation solving the field equations. The equation relates a solution "generating function" with the scalar potential. We analyze its stability and find a later time attractor which describes a Universe approaching to an eternal-de Sitter inflation driven by the potential energy, V0>0. The attractor exists when the potential is regular and does not have a linear and quadratic terms of the field. When the potential has a mass term, the attractor exists if the scalar field is in a symmetric phase and is weakly coupled, λ<9V0/16. We also find that the attractor property is intact under small modifications of the potential. If the scalar field has a positive mass-squared or is strongly coupled, there exists a quasi-attractor. However, the quasi-attractor property disappears if the potential is modified. On the whole, the appearance of the eternal inflation is not rare in scalar cosmology in the presence of an attractor.

  18. Extended scalar-tensor theories of gravity

    NASA Astrophysics Data System (ADS)

    Crisostomi, Marco; Koyama, Kazuya; Tasinato, Gianmassimo

    2016-04-01

    We study new consistent scalar-tensor theories of gravity recently introduced by Langlois and Noui with potentially interesting cosmological applications. We derive the conditions for the existence of a primary constraint that prevents the propagation of an additional dangerous mode associated with higher order equations of motion. We then classify the most general, consistent scalar-tensor theories that are at most quadratic in the second derivatives of the scalar field. In addition, we investigate the possible connection between these theories and (beyond) Horndeski through conformal and disformal transformations. Finally, we point out that these theories can be associated with new operators in the effective field theory of dark energy, which might open up new possibilities to test dark energy models in future surveys.

  19. Recent progress on light scalar mesons

    SciTech Connect

    Peláez, J. R.

    2014-07-23

    This is a brief account of the recent developments on the determination of the mass and widths of the much debated scalar mesons, paying particular attention to the causes of major revision of the σ or f{sub 0}(500) meson in the last edition of the Review of Particle Physics, which has finally acknowledged that the situation concerning the mass and width of this controversial state has been settled, although this was already well-known to scalar meson practitioners for about a decade. I will briefly comment on the dispersive approach, followed by several groups, which seems to have been the most decisive in support of the existence and precise determinations of scalar meson properties.

  20. Electrophobic Scalar Boson and Muonic Puzzles.

    PubMed

    Liu, Yu-Sheng; McKeen, David; Miller, Gerald A

    2016-09-01

    A new scalar boson which couples to the muon and proton can simultaneously solve the proton radius puzzle and the muon anomalous magnetic moment discrepancy. Using a variety of measurements, we constrain the mass of this scalar and its couplings to the electron, muon, neutron, and proton. Making no assumptions about the underlying model, these constraints and the requirement that it solve both problems limit the mass of the scalar to between about 100 keV and 100 MeV. We identify two unexplored regions in the coupling constant-mass plane. Potential future experiments and their implications for theories with mass-weighted lepton couplings are discussed. PMID:27636468

  1. The Neural Computation of Scalar Implicature

    PubMed Central

    Hartshorne, Joshua K.; Snedeker, Jesse; Azar, Stephanie Yen-Mun Liem; Kim, Albert E.

    2014-01-01

    Language comprehension involves not only constructing the literal meaning of a sentence but also going beyond the literal meaning to infer what was meant but not said. One widely-studied test case is scalar implicature: The inference that, e.g., Sally ate some of the cookies implies she did not eat all of them. Research is mixed on whether this is due to a rote, grammaticalized procedure or instead a complex, contextualized inference. We find that in sentences like If Sally ate some of the cookies, then the rest are on the counter, that the rest triggers a late, sustained positivity relative to Sally ate some of the cookies, and the rest are on the counter. This is consistent with behavioral results and linguistic theory suggesting that the former sentence does not trigger a scalar implicature. This motivates a view on which scalar implicature is contextualized but dependent on grammatical structure. PMID:25914890

  2. Exploring scalar field dynamics with Gaussian processes

    SciTech Connect

    Nair, Remya; Jhingan, Sanjay; Jain, Deepak E-mail: sanjay.jhingan@gmail.com

    2014-01-01

    The origin of the accelerated expansion of the Universe remains an unsolved mystery in Cosmology. In this work we consider a spatially flat Friedmann-Robertson-Walker (FRW) Universe with non-relativistic matter and a single scalar field contributing to the energy density of the Universe. Properties of this scalar field, like potential, kinetic energy, equation of state etc. are reconstructed from Supernovae and BAO data using Gaussian processes. We also reconstruct energy conditions and kinematic variables of expansion, such as the jerk and the slow roll parameter. We find that the reconstructed scalar field variables and the kinematic quantities are consistent with a flat ΛCDM Universe. Further, we find that the null energy condition is satisfied for the redshift range of the Supernovae data considered in the paper, but the strong energy condition is violated.

  3. Entanglement from longitudinal and scalar photons

    SciTech Connect

    Franson, J. D

    2011-09-15

    The covariant quantization of the electromagnetic field in the Lorentz gauge gives rise to longitudinal and scalar photons in addition to the usual transverse photons. It is shown here that the exchange of longitudinal and scalar photons can produce entanglement between two distant atoms or harmonic oscillators. The form of the entangled states produced in this way is very different from that obtained in the Coulomb gauge, where the longitudinal and scalar photons do not exist. A generalized gauge transformation is used to show that all physically observable effects are the same in the two gauges, despite the differences in the form of the entangled states. An approach of this kind may be useful for a covariant description of the dynamics of quantum information processing.

  4. Dimensionality influence on passive scalar transport

    NASA Astrophysics Data System (ADS)

    Iovieno, M.; Ducasse, L.; Tordella, D.

    2011-12-01

    We numerically investigate the advection of a passive scalar through an interface placed inside a decaying shearless turbulent mixing layer. We consider the system in both two and three dimensions. The dimensionality produces a different time scaling of the diffusion, which is faster in the two-dimensional case. Two intermittent fronts are generated at the margins of the mixing layer. During the decay these fronts present a sort of propagation in both the direction of the scalar flow and the opposite direction. In two dimensions, the propagation of the fronts exhibits a significant asymmetry with respect to the initial position of the interface and is deeper for the front merged in the high energy side of the mixing. In three dimensions, the two fronts remain nearly symmetrically placed. Results concerning the scalar spectra exponents are also presented.

  5. Scalar discrete nonlinear multipoint boundary value problems

    NASA Astrophysics Data System (ADS)

    Rodriguez, Jesus; Taylor, Padraic

    2007-06-01

    In this paper we provide sufficient conditions for the existence of solutions to scalar discrete nonlinear multipoint boundary value problems. By allowing more general boundary conditions and by imposing less restrictions on the nonlinearities, we obtain results that extend previous work in the area of discrete boundary value problems [Debra L. Etheridge, Jesus Rodriguez, Periodic solutions of nonlinear discrete-time systems, Appl. Anal. 62 (1996) 119-137; Debra L. Etheridge, Jesus Rodriguez, Scalar discrete nonlinear two-point boundary value problems, J. Difference Equ. Appl. 4 (1998) 127-144].

  6. Scalar operators in solid-state NMR

    SciTech Connect

    Sun, Boqin

    1991-11-01

    Selectivity and resolution of solid-state NMR spectra are determined by dispersion of local magnetic fields originating from relaxation effects and orientation-dependent resonant frequencies of spin nuclei. Theoretically, the orientation-dependent resonant frequencies can be represented by a set of irreducible tensors. Among these tensors, only zero rank tensors (scalar operators) are capable of providing high resolution NMR spectra. This thesis presents a series of new developments in high resolution solid-state NMR concerning the reconstruction of various scalar operators motion in solid C{sub 60} is analyzed.

  7. Halos of unified dark matter scalar field

    SciTech Connect

    Bertacca, Daniele; Bartolo, Nicola; Matarrese, Sabino E-mail: nicola.bartolo@pd.infn.it

    2008-05-15

    We investigate the static and spherically symmetric solutions of Einstein's equations for a scalar field with a non-canonical kinetic term, assumed to provide both the dark matter and dark energy components of the Universe. In particular, we give a prescription to obtain solutions (dark halos) whose rotation curve v{sub c}(r) is in good agreement with observational data. We show that there exist suitable scalar field Lagrangians that allow us to describe the cosmological background evolution and the static solutions with a single dark fluid.

  8. A Search for Scalar Chameleons with ADMX

    SciTech Connect

    Rybka, G.; Hotz, M.; Rosenberg, L.J.; Asztalos, S.J.; Carosi, G.; Hagmann, C.; Kinion, D.; van Bibber, K.; Hoskins, J.; Martin, C.; Sikivie, P.; Tanner, D.B.; Bradley, R.; Clarke, J.

    2010-04-26

    Scalar fields with a"chameleon" property, in which the effective particle mass is a function of its local environment, are common to many theories beyond the standard model and could be responsible for dark energy. If these fields couple weakly to the photon, they could be detectable through the afterglow effect of photon-chameleon-photon transitions. The ADMX experiment was used in the first chameleon search with a microwave cavity to set a new limit on scalar chameleon-photon coupling beta_gamma excluding values between 2x109 and 5x1014 for effective chameleon masses between 1.9510 and 1:9525 micro eV.

  9. On causality in polymer scalar field theory

    NASA Astrophysics Data System (ADS)

    García-Chung, Angel A.; Morales-Técotl, Hugo A.

    2011-10-01

    The properties of spacetime corresponding to a proposed quantum gravity theory might modify the high energy behavior of quantum fields. Motivated by loop quantum gravity, recently, Hossain et al [1] have considered a polymer field algebra that replaces the standard canonical one in order to calculate the propagator of a real scalar field in flat spacetime. This propagator features Lorentz violations. Motivated by the relation between Lorentz invariance and causality in standard Quantum Field Theory, in this work we investigate the causality behavior of the polymer scalar field.

  10. Composite scalar dark matter from vector-like SU(2) confinement

    NASA Astrophysics Data System (ADS)

    Pasechnik, Roman; Beylin, Vitaly; Kuksa, Vladimir; Vereshkov, Grigory

    2016-03-01

    A toy-model with SU(2)TC dynamics confined at high scales ΛTC ≫ 100GeV enables to construct Dirac UV completion from the original chiral multiplets predicting a vector-like nature of their weak interactions consistent with electroweak precision tests. In this work, we investigate a potential of the lightest scalar baryon-like (T-baryon) state B0 = UD with mass mB ≳ 1TeV predicted by the simplest two-flavor vector-like confinement model as a dark matter (DM) candidate. We show that two different scenarios with the T-baryon relic abundance formation before and after the electroweak (EW) phase transition epoch lead to symmetric (or mixed) and asymmetric DM, respectively. Such a DM candidate evades existing direct DM detection constraints since its vector coupling to Z boson absents at tree level, while one-loop gauge boson mediated contribution is shown to be vanishingly small close to the threshold. The dominating spin-independent (SI) T-baryon-nucleon scattering goes via tree-level Higgs boson exchange in the t-channel. The corresponding bound on the effective T-baryon-Higgs coupling has been extracted from the recent LUX data and turns out to be consistent with naive expectations from the light technipion case mπ˜ ≪ ΛTC. The latter provides the most stringent phenomenological constraint on strongly-coupled SU(2)TC dynamics so far. Future prospects for direct and indirect scalar T-baryon DM searches in astrophysics as well as in collider measurements have been discussed.

  11. An improved mixing model providing joint statistics of scalar and scalar dissipation

    SciTech Connect

    Meyer, Daniel W.; Jenny, Patrick

    2008-11-15

    For the calculation of nonpremixed turbulent flames with thin reaction zones the joint probability density function (PDF) of the mixture fraction and its dissipation rate plays an important role. The corresponding PDF transport equation involves a mixing model for the closure of the molecular mixing term. Here, the parameterized scalar profile (PSP) mixing model is extended to provide the required joint statistics. Model predictions are validated using direct numerical simulation (DNS) data of a passive scalar mixing in a statistically homogeneous turbulent flow. Comparisons between the DNS and the model predictions are provided, which involve different initial scalar-field lengthscales. (author)

  12. Acetylcholine-Binding Protein in the Hemolymph of the Planorbid Snail Biomphalaria glabrata Is a Pentagonal Dodecahedron (60 Subunits)

    PubMed Central

    Kapetanopoulos, Katharina; Braukmann, Sandra; Gebauer, Wolfgang; Tenzer, Stefan; Markl, Jürgen

    2012-01-01

    Nicotinic acetylcholine receptors (nAChR) play important neurophysiological roles and are of considerable medical relevance. They have been studied extensively, greatly facilitated by the gastropod acetylcholine-binding proteins (AChBP) which represent soluble structural and functional homologues of the ligand-binding domain of nAChR. All these proteins are ring-like pentamers. Here we report that AChBP exists in the hemolymph of the planorbid snail Biomphalaria glabrata (vector of the schistosomiasis parasite) as a regular pentagonal dodecahedron, 22 nm in diameter (12 pentamers, 60 active sites). We sequenced and recombinantly expressed two ∼25 kDa polypeptides (BgAChBP1 and BgAChBP2) with a specific active site, N-glycan site and disulfide bridge variation. We also provide the exon/intron structures. Recombinant BgAChBP1 formed pentamers and dodecahedra, recombinant BgAChBP2 formed pentamers and probably disulfide-bridged di-pentamers, but not dodecahedra. Three-dimensional electron cryo-microscopy (3D-EM) yielded a 3D reconstruction of the dodecahedron with a resolution of 6 Å. Homology models of the pentamers docked to the 6 Å structure revealed opportunities for chemical bonding at the inter-pentamer interfaces. Definition of the ligand-binding pocket and the gating C-loop in the 6 Å structure suggests that 3D-EM might lead to the identification of functional states in the BgAChBP dodecahedron. PMID:22916297

  13. Scalar field theory on fuzzy S 4

    NASA Astrophysics Data System (ADS)

    Medina, Julieta; O'Connor, Denjoe

    2003-11-01

    Scalar fields are studied on fuzzy S 4 and a solution is found for the elimination of the unwanted degrees of freedom that occur in the model. The resulting theory can be interpreted as a Kaluza-Klein reduction of Bbb CP3 to S 4 in the fuzzy context.

  14. Kerr black holes with scalar hair.

    PubMed

    Herdeiro, Carlos A R; Radu, Eugen

    2014-06-01

    We present a family of solutions of Einstein's gravity minimally coupled to a complex, massive scalar field, describing asymptotically flat, spinning black holes with scalar hair and a regular horizon. These hairy black holes (HBHs) are supported by rotation and have no static limit. Besides mass M and angular momentum J, they carry a conserved, continuous Noether charge Q measuring the scalar hair. HBHs branch off from the Kerr metric at the threshold of the superradiant instability and reduce to spinning boson stars in the limit of vanishing horizon area. They overlap with Kerr black holes for a set of (M, J) values. A single Killing vector field preserves the solutions, tangent to the null geodesic generators of the event horizon. HBHs can exhibit sharp physical differences when compared to the Kerr solution, such as J/M^{2}>1, a quadrupole moment larger than J^{2}/M, and a larger orbital angular velocity at the innermost stable circular orbit. Families of HBHs connected to the Kerr geometry should exist in scalar (and other) models with more general self-interactions.

  15. Scalar Mesons in B-decays

    SciTech Connect

    Minkowski, Peter; Ochs, Wolfgang

    2006-02-11

    We summarize some persistent problems in scalar spectroscopy and discuss what could be learned here from charmless B-decays. Recent experimental results are discussed in comparison with theoretical expectations: a simple model based on penguin dominance leads to various symmetry relations in good agreement with recent data; a factorisation approach yields absolute predictions of rates.

  16. Cosmological simulations: the role of scalar fields

    SciTech Connect

    Rodriguez-Meza, M. A.

    2009-04-20

    We present numerical N-body simulation studies of large-scale structure formation. The main purpose of these studies is to analyze the several models of dark matter and the role they played in the process of large-scale structure formation. We analyze the standard and more successful case, i.e., the cold dark matter with cosmological constant ({lambda}CDM). We compare the results of this model with the corresponding results of other alternative models, in particular, the models that can be built from the Newtonian limit of alternative theories of gravity like scalar-tensor theories. An specific model is the one that considers that the scalar field is non-minimally coupled to the Ricci scalar in the Einstein-Hilbert Lagrangian that gives, in the Newtonian limit an effective gravitational force that is given by two contributions: the standard Newtonian potential plus a Yukawa potential that comes from a massive scalar field. Comparisons of the models are done by analyzing the snapshots of the N-body system at z = 0 for several values of the SF parameters.

  17. Scalar field radiation from dilatonic black holes

    NASA Astrophysics Data System (ADS)

    Gohar, H.; Saifullah, K.

    2012-12-01

    We study radiation of scalar particles from charged dilaton black holes. The Hamilton-Jacobi method has been used to work out the tunneling probability of outgoing particles from the event horizon of dilaton black holes. For this purpose we use WKB approximation to solve the charged Klein-Gordon equation. The procedure gives Hawking temperature for these black holes as well.

  18. Black holes in scalar-tensor gravity.

    PubMed

    Sotiriou, Thomas P; Faraoni, Valerio

    2012-02-24

    Hawking has proven that black holes which are stationary as the end point of gravitational collapse in Brans-Dicke theory (without a potential) are no different than in general relativity. We extend this proof to the much more general class of scalar-tensor and f(R) gravity theories, without assuming any symmetries apart from stationarity.

  19. Dynamical scalarization of neutron stars in scalar-tensor gravity theories

    NASA Astrophysics Data System (ADS)

    Palenzuela, Carlos; Barausse, Enrico; Ponce, Marcelo; Lehner, Luis

    2014-02-01

    We present a framework to study generic neutron-star binaries in scalar-tensor theories of gravity. Our formalism achieves this goal by suitably interfacing a post-Newtonian orbital evolution (described by a set of ordinary differential equations) with a set of nonlinear algebraic equations, which provide a description of the scalar charge of each binary's component along the evolution in terms of isolated-star data. We validate this semianalytical procedure by comparing its results to those of fully general-relativistic simulations, and use it to investigate the behavior of binary systems in large portions of the parameter space of scalar-tensor theories. This allows us to shed further light on the phenomena of "dynamical scalarization," which we uncovered in [E. Barausse et al., Phys. Rev. D 87, 081506(R) (2013)] and which takes place in tight binaries, even for stars that have exactly zero scalar charge in isolation. We also employ our formalism to study representative binary systems, obtain their gravitational-wave signals and discuss the extent to which deviations from general relativity can be detected. The insights gained by this framework allow us to additionally show that eccentric binaries can undergo scalarization/descalarization phenomena.

  20. Black holes with surrounding matter in scalar-tensor theories.

    PubMed

    Cardoso, Vitor; Carucci, Isabella P; Pani, Paolo; Sotiriou, Thomas P

    2013-09-13

    We uncover two mechanisms that can render Kerr black holes unstable in scalar-tensor gravity, both associated with the presence of matter in the vicinity of the black hole and the fact that this introduces an effective mass for the scalar. Our results highlight the importance of understanding the structure of spacetime in realistic, astrophysical black holes in scalar-tensor theories.

  1. Scalar field in the anisotropic universe

    SciTech Connect

    Kim, Hyeong-Chan; Minamitsuji, Masato

    2010-04-15

    We discuss the primordial spectrum of a massless and minimally coupled scalar field, produced during the initial anisotropic epoch before the onset of inflation. We consider two models of the anisotropic cosmology, the (planar) Kasner-de Sitter solution (Bianchi I) and the Taub-NUT-de Sitter solution (Bianchi IX), where the 3-space geometry is initially anisotropic, followed by the de Sitter phase due to the presence of a positive cosmological constant. We discuss the behavior of a quantized, massless and minimally coupled scalar field in the anisotropic stage. This scalar field is not the inflaton and hence does not contribute to the background dynamics. We focus on the quantization procedure and evolution in the preinflationary anisotropic background. Also, in this paper for simplicity the metric perturbations are not taken into account. The initial condition is set by the requirement that the scalar field is initially in an adiabatic state. Usually, in a quantum harmonic oscillator system, an adiabatic process implies the one where the potential changes slowly enough compared to its size, and the time evolution can be obtained from the zeroth order WKB approximation. In our case, such a vacuum state exists only for limited solutions of the anisotropic universe, whose spacetime structure is regular in the initial times. In this paper, we call our adiabatic vacuum state the anisotropic vacuum. In the Kasner-de Sitter model, for one branch of planar solutions there is an anisotropic vacuum unless k{sub 3{ne}}0, where k{sub 3} is the comoving momentum along the third direction, while in the other branch there is no anisotropic vacuum state. In the first branch, for the moderate modes, k{sub 3{approx}}k, where k is the total comoving momentum, the scalar power spectrum has an oscillatory behavior and its direction dependence is suppressed. For the planar modes, k{sub 3}<

  2. Bingel-Hirsch addition on non-isolated-pentagon-rule Gd3N@C2n (2n = 82 and 84) metallofullerenes: products under kinetic control.

    PubMed

    Alegret, Núria; Salvadó, Patricia; Rodríguez-Fortea, Antonio; Poblet, Josep M

    2013-10-01

    Bingel-Hirsch reactions on fullerenes take place under kinetic control. We here predict, by means of DFT methodology, the products of the Bingel-Hirsch addition on non-isolated-pentagon-rule (non-IPR) metallofullerenes Gd3N@C2n (2n = 82, 84), as modeled by closed-shell Y3N@C2n systems. Adducts on [6,6] B-type bonds placed near the pentalene unit are predicted for the two cages, as found for other non-IPR endohedral fullerenes such as Sc3N@C68.

  3. Stationary charged scalar clouds around black holes in string theory

    NASA Astrophysics Data System (ADS)

    Bernard, Canisius

    2016-10-01

    It was reported that Kerr-Newman black holes can support linear charged scalar fields in their exterior regions. These stationary massive charged scalar fields can form bound states, which are called stationary scalar clouds. In this paper, we show that Kerr-Sen black holes can also support stationary massive charged scalar clouds by matching the near- and far-region solutions of the radial part of the Klein-Gordon wave equation. We also review stationary scalar clouds within the background of static electrically charged black hole solutions in the low-energy limit of heterotic string field theory, namely, the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black holes.

  4. Highly compact neutron stars in scalar-tensor theories of gravity: Spontaneous scalarization versus gravitational collapse

    NASA Astrophysics Data System (ADS)

    Mendes, Raissa F. P.; Ortiz, Néstor

    2016-06-01

    Scalar-tensor theories of gravity are extensions of general relativity (GR) including an extra, nonminimally coupled scalar degree of freedom. A wide class of these theories, albeit indistinguishable from GR in the weak field regime, predicts a radically different phenomenology for neutron stars, due to a nonperturbative, strong-field effect referred to as spontaneous scalarization. This effect is known to occur in theories where the effective linear coupling β0 between the scalar and matter fields is sufficiently negative, i.e. β0≲-4.35 , and has been strongly constrained by pulsar timing observations. In the test-field approximation, spontaneous scalarization manifests itself as a tachyonic-like instability. Recently, it was argued that, in theories where β0>0 , a similar instability would be triggered by sufficiently compact neutron stars obeying realistic equations of state. In this work we investigate the end state of this instability for some representative coupling functions with β0>0 . This is done both through an energy balance analysis of the existing equilibrium configurations, and by numerically determining the nonlinear Cauchy development of unstable initial data. We find that, contrary to the β0<0 case, the final state of the instability is highly sensitive to the details of the coupling function, varying from gravitational collapse to spontaneous scalarization. In particular, we show, for the first time, that spontaneous scalarization can happen in theories with β0>0 , which could give rise to novel astrophysical tests of the theory of gravity.

  5. Continuity of scalar fields with logarithmic correlations

    NASA Astrophysics Data System (ADS)

    Rajeev, S. G.; Ranken, Evan

    2015-08-01

    We apply select ideas from the modern theory of stochastic processes in order to study the continuity/roughness of scalar quantum fields. A scalar field with logarithmic correlations (such as a massless field in 1 +1 spacetime dimensions) has the mildest of singularities, making it a logical starting point. Instead of the usual inner product of the field with a smooth function, we introduce a moving average on an interval which allows us to obtain explicit results and has a simple physical interpretation. Using the mathematical work of Dudley, we prove that the averaged random process is in fact continuous, and give a precise modulus of continuity bounding the short-distance variation.

  6. Scalar waves in a wormhole geometry

    SciTech Connect

    Kar, S.; Sahdev, D. ); Bhawal, B. )

    1994-01-15

    The reflection and transmission of massless scalar waves in the curved background geometry of a typical Lorentzian wormhole (in 2+1 and 3+1 dimensions) are discussed. Using the exact solutions which involve modified Mathieu (in 2+1 dimensions) and radial oblate spheroidal (in 3+1 dimensions) functions, explicit analytic expressions are obtained for the reflection and transmission coefficients at specific values of the quantity [omega][ital b][sub 0] ([omega] being the energy of the scalar wave and [ital b][sub 0] the throat radius of the wormhole). It is found that both near-perfect reflection as well as transmission are possible for specific choices of certain parameters.

  7. Scalar field cosmologies with inverted potentials

    SciTech Connect

    Boisseau, B.; Giacomini, H.

    2015-10-01

    Regular bouncing solutions in the framework of a scalar-tensor gravity model were found in a recent work. We reconsider the problem in the Einstein frame (EF) in the present work. Singularities arising at the limit of physical viability of the model in the Jordan frame (JF) are either of the Big Bang or of the Big Crunch type in the EF. As a result we obtain integrable scalar field cosmological models in general relativity (GR) with inverted double-well potentials unbounded from below which possess solutions regular in the future, tending to a de Sitter space, and starting with a Big Bang. The existence of the two fixed points for the field dynamics at late times found earlier in the JF becomes transparent in the EF.

  8. Swarm's Absolute Scalar Magnetometer metrological performances

    NASA Astrophysics Data System (ADS)

    Leger, J.; Fratter, I.; Bertrand, F.; Jager, T.; Morales, S.

    2012-12-01

    The Absolute Scalar Magnetometer (ASM) has been developed for the ESA Earth Observation Swarm mission, planned for launch in November 2012. As its Overhauser magnetometers forerunners flown on Oersted and Champ satellites, it will deliver high resolution scalar measurements for the in-flight calibration of the Vector Field Magnetometer manufactured by the Danish Technical University. Latest results of the ground tests carried out to fully characterize all parameters that may affect its accuracy, both at instrument and satellite level, will be presented. In addition to its baseline function, the ASM can be operated either at a much higher sampling rate (burst mode at 250 Hz) or in a dual mode where it also delivers vector field measurements as a by-product. The calibration procedure and the relevant vector performances will be discussed.

  9. Anisotropic inflation from charged scalar fields

    SciTech Connect

    Emami, Razieh; Firouzjahi, Hassan; Movahed, S.M. Sadegh; Zarei, Moslem E-mail: firouz@ipm.ir E-mail: m.zarei@cc.iut.ac.ir

    2011-02-01

    We consider models of inflation with U(1) gauge fields and charged scalar fields including symmetry breaking potential, chaotic inflation and hybrid inflation. We show that there exist attractor solutions where the anisotropies produced during inflation becomes comparable to the slow-roll parameters. In the models where the inflaton field is a charged scalar field the gauge field becomes highly oscillatory at the end of inflation ending inflation quickly. Furthermore, in charged hybrid inflation the onset of waterfall phase transition at the end of inflation is affected significantly by the evolution of the background gauge field. Rapid oscillations of the gauge field and its coupling to inflaton can have interesting effects on preheating and non-Gaussianities.

  10. Unruh effect in a real scalar field with the Higgs potential on a dynamically variable background space-time

    NASA Astrophysics Data System (ADS)

    Takeuchi, Shingo

    2015-09-01

    It is predicted that an accelerating electron performs a Brownian motion in the inertial frame. This Brownian motion in the inertial frame has its roots in the interaction with the thermal excitation given by the Unruh effect in the accelerating frame. If such a prediction is possible, correspondingly we propose a prediction in this study that the thermal radiation is emitted in the inertial frame from an electron heated due to the Unruh effect in the accelerating frame. The point in our prediction is, although the Unruh effect is limited in the accelerating frame, as well as that the Brownian motion rooted in the Unruh effect appears in the inertial frame, the heat of the particle appears in the inertial frame. Based on such a prediction in this paper, we investigate phenomena in the neighborhood of an accelerating electron in the inertial frame. The model we consider is the four-dimensional Klein-Gordon real scalar field model with the Higgs potential term at the finite temperature identified with the Unruh temperature on the de Sitter space-time. We calculate the one-loop effective potential in the inertial frame with the corrections by the thermal radiation rooted in the Unruh effect in the accelerating frame. In this calculation, we take into account that the background space-time is deformed due to the field theory's corrected one-loop effective potential. Based on such an analysis, we illustrate the restoration of the spontaneous symmetry breaking and the dynamical variation of the background space-time, and we examine the accelerating particle's world-line and the amount of the energy corresponding to the change of the acceleration.

  11. Noncommutative scalar fields from symplectic deformation

    SciTech Connect

    Daoud, M.; Hamama, A.

    2008-02-15

    This paper is concerned with the quantum theory of noncommutative scalar fields in two dimensional space-time. It is shown that the noncommutativity originates from the the deformation of symplectic structures. The quantization is performed and the modes expansions of the fields, in the presence of an electromagnetic background, are derived. The Hamiltonian of the theory is given and the degeneracies lifting, induced by the deformation, is also discussed.

  12. FESDIF -- Finite Element Scalar Diffraction theory code

    SciTech Connect

    Kraus, H.G.

    1992-09-01

    This document describes the theory and use of a powerful scalar diffraction theory based computer code for calculation of intensity fields due to diffraction of optical waves by two-dimensional planar apertures and lenses. This code is called FESDIF (Finite Element Scalar Diffraction). It is based upon both Fraunhofer and Kirchhoff scalar diffraction theories. Simplified routines for circular apertures are included. However, the real power of the code comes from its basis in finite element methods. These methods allow the diffracting aperture to be virtually any geometric shape, including the various secondary aperture obstructions present in telescope systems. Aperture functions, with virtually any phase and amplitude variations, are allowed in the aperture openings. Step change aperture functions are accommodated. The incident waves are considered to be monochromatic. Plane waves, spherical waves, or Gaussian laser beams may be incident upon the apertures. Both area and line integral transformations were developed for the finite element based diffraction transformations. There is some loss of aperture function generality in the line integral transformations which are typically many times more computationally efficient than the area integral transformations when applicable to a particular problem.

  13. Scalar meson spectroscopy with lattice staggered fermions

    SciTech Connect

    Bernard, Claude; DeTar, Carleton; Fu Ziwen; Prelovsek, Sasa

    2007-11-01

    With sufficiently light up and down quarks the isovector (a{sub 0}) and isosinglet (f{sub 0}) scalar meson propagators are dominated at large distance by two-meson states. In the staggered-fermion formulation of lattice quantum chromodynamics, taste-symmetry breaking causes a proliferation of two-meson states that further complicates the analysis of these channels. Many of them are unphysical artifacts of the lattice approximation. They are expected to disappear in the continuum limit. The staggered-fermion fourth-root procedure has its purported counterpart in rooted staggered chiral perturbation theory (rS{chi}PT). Fortunately, the rooted theory provides a strict framework that permits the analysis of scalar meson correlators in terms of only a small number of low-energy couplings. Thus the analysis of the point-to-point scalar meson correlators in this context gives a useful consistency check of the fourth-root procedure and its proposed chiral realization. Through numerical simulation we have measured correlators for both the a{sub 0} and f{sub 0} channels in the 'Asqtad' improved staggered-fermion formulation in a lattice ensemble with lattice spacing a=0.12 fm. We analyze those correlators in the context of rS{chi}PT and obtain values of the low-energy chiral couplings that are reasonably consistent with previous determinations.

  14. Age Crises, Scalar Fields, and the Apocalypse

    NASA Astrophysics Data System (ADS)

    Jackson, J. C.

    Recent observations suggest that Hubble's constant is large, to the extent that the oldest stars appear to have ages which are greater than the Hubble time, and that the Hubble expansion is slowing down, so that according to conventional cosmology the age of the Universe is less than the Hubble time. The concepts of weak and strong age crises (respectively t0<1/H0 but longer than the age inferred from some lower limit on q0, and t0>1/H0 and q0>0) are introduced. These observations are reconciled in models which are dynamically dominated by a homogeneous scalar field, corresponding to an ultra-light boson whose Compton wavelength is of the same order as the Hubble radius. Two such models are considered, an open one with vacuum energy comprising a conventional cosmological term and a scalar field component, and a flat one with a scalar component only, aimed respectively at weak and strong age crises. Both models suggest that anti-gravity plays a significant role in the evolution of the Universe.

  15. Cosmological scalar field perturbations can grow

    NASA Astrophysics Data System (ADS)

    Alcubierre, Miguel; de la Macorra, Axel; Diez-Tejedor, Alberto; Torres, José M.

    2015-09-01

    It has been argued that the small perturbations to the homogeneous and isotropic configurations of a canonical scalar field in an expanding universe do not grow. We show that this is not true in general, and clarify the root of the misunderstanding. We revisit a simple model in which the zero mode of a free scalar field oscillates with high frequency around the minimum of the potential. Under this assumption the linear perturbations grow like those in the standard cold dark matter scenario, but with a Jeans length at the scale of the Compton wavelength of the scalar particle. Contrary to previous analyses in the literature our results do not rely on time averages and/or fluid identifications, and instead we solve both analytically (in terms of a well-defined series expansion) and numerically the linearized Einstein-Klein-Gordon system. Also, we use gauge-invariant fields, which makes the physical analysis more transparent and simplifies the comparison with previous works carried out in different gauges. As a byproduct of this study we identify a time-dependent modulation of the different physical quantities associated to the background as well as the perturbations with potential observational consequences in dark matter models.

  16. Scalar-vector quantization of medical images.

    PubMed

    Mohsenian, N; Shahri, H; Nasrabadi, N M

    1996-01-01

    A new coding scheme based on the scalar-vector quantizer (SVQ) is developed for compression of medical images. The SVQ is a fixed rate encoder and its rate-distortion performance is close to that of optimal entropy-constrained scalar quantizers (ECSQs) for memoryless sources. The use of a fixed-rate quantizer is expected to eliminate some of the complexity of using variable-length scalar quantizers. When transmission of images over noisy channels is considered, our coding scheme does not suffer from error propagation that is typical of coding schemes using variable-length codes. For a set of magnetic resonance (MR) images, coding results obtained from SVQ and ECSQ at low bit rates are indistinguishable. Furthermore, our encoded images are perceptually indistinguishable from the original when displayed on a monitor. This makes our SVQ-based coder an attractive compression scheme for picture archiving and communication systems (PACS). PACS are currently under study for use in an all-digital radiology environment in hospitals, where reliable transmission, storage, and high fidelity reconstruction of images are desired. PMID:18285124

  17. Generating time dependent conformally coupled Einstein-scalar solutions

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph

    2015-07-01

    Using the correspondence between a minimally coupled scalar field and an effective stiff perfect fluid with or without a cosmological constant, we present a simple method for generating time dependent Einstein-scalar solutions with a conformally coupled scalar field that has vanishing or non-vanishing potential. This is done by using Bekenstein's transformation on Einstein-scalar solutions with minimally coupled massless scalar fields, and its later generalization by Abreu et al. to massive fields. In particular we obtain two new spherically symmetric time dependent solutions to the coupled system of Einstein's and the conformal scalar field equations, with one of the solutions having a Higgs' type potential for the scalar field, and we study their properties.

  18. Synthesis and structure of K{sub 10}Tl{sub 7}: The first binary trielide containing naked pentagonal bipyramidal Tl{sub 7} clusters

    SciTech Connect

    Kaskel, S.; Corbett, J.D.

    2000-02-21

    The title compound is synthesized by direct fusion of the elements at 400 C followed by annealing at 330 C, quenching to room temperature, and subsequent annealing at 120 and 100 C for days to weeks. The compound crystallizes in the monoclinic space group P2{sub 1}/c (No. 14), with Z = 4, a = 10.132(1){angstrom}, b = 22.323(2){angstrom}, c = 13.376(1){angstrom}, and {beta} = 93.14(1){degree}, and consists of Tl{sub 7}{sup 7{minus}} clusters embedded in a matrix of potassium ions. The cluster is an axially compressed pentagonal bipyramid close to D{sub 5h} symmetry. The apex-apex bond distance (3.462(1){angstrom}) is little longer than the bonds in the pentagonal waist (3.183(1)--3.247(1){angstrom}). Structurally the compound is not electron-precise: K{sub 10}Tl{sub 7} has three extra electrons per Tl{sub 7} cluster and is Pauli paramagnetic ({chi}{sub 300} = 2.25 x 10{sup {minus}4} emu/mol).

  19. (An)Isotropic models in scalar and scalar-tensor cosmologies

    NASA Astrophysics Data System (ADS)

    Belinchón, José Antonio

    2012-04-01

    We study how the constants G and Λ may vary in different theoretical models (general relativity with a perfect fluid, scalar cosmological models ("quintessence") with and without interacting scalar and matter fields and a scalar-tensor model with a dynamical Λ) in order to explain some observational results. We apply the program outlined in section II to study three different geometries which generalize the FRW ones, which are Bianchi V, VII0 and IX, under the self-similarity hypothesis. We put special emphasis on calculating exact power-law solutions which allow us to compare the different models. In all the studied cases we arrive at the conclusion that the solutions are isotropic and noninflationary while the cosmological constant behaves as a positive decreasing time function (in agreement with the current observations) and the gravitational constant behaves as a growing time function.

  20. Astrophysical effects of scalar dark matter miniclusters

    NASA Astrophysics Data System (ADS)

    Zurek, Kathryn M.; Hogan, Craig J.; Quinn, Thomas R.

    2007-02-01

    We model the formation, evolution and astrophysical effects of dark compact Scalar Miniclusters (“ScaMs”). These objects arise when a scalar field, with an axion-like or Higgs-like potential, undergoes a second-order phase transition below the QCD scale. Such a scalar field may couple too weakly to the standard model to be detectable directly through particle interactions, but may still be detectable by gravitational effects, such as lensing and baryon accretion by large, gravitationally bound miniclusters. The masses of these objects are shown to be constrained by the Lyα power spectrum to be less than ˜104M⊙, but they may be as light as classical axion miniclusters, of the order of 10-12M⊙. We simulate the formation and nonlinear gravitational collapse of these objects around matter-radiation equality using an N-body code, estimate their gravitational lensing properties, and assess the feasibility of studying them using current and future lensing experiments. Future MACHO-type variability surveys of many background sources can reveal either high-amplification, strong-lensing events, or measure density profiles directly via weak-lensing variability, depending on ScaM parameters and survey depth. However, ScaMs, due to their low internal densities, are unlikely to be responsible for apparent MACHO events already detected in the Galactic halo. As a result, in the entire window between 10-7M⊙ and 102M⊙ covered by the galactic scale lensing experiments, ScaMs may in fact compose all the dark matter. A simple estimate is made of parameters that would give rise to early structure formation; in principle, early stellar collapse could be triggered by ScaMs as early as recombination, and significantly affect cosmic reionization.

  1. Astrophysical effects of scalar dark matter miniclusters

    SciTech Connect

    Zurek, Kathryn M.; Hogan, Craig J.; Quinn, Thomas R.

    2007-02-15

    We model the formation, evolution and astrophysical effects of dark compact Scalar Miniclusters ('ScaMs'). These objects arise when a scalar field, with an axion-like or Higgs-like potential, undergoes a second-order phase transition below the QCD scale. Such a scalar field may couple too weakly to the standard model to be detectable directly through particle interactions, but may still be detectable by gravitational effects, such as lensing and baryon accretion by large, gravitationally bound miniclusters. The masses of these objects are shown to be constrained by the Ly{alpha} power spectrum to be less than {approx}10{sup 4}M{sub {center_dot}}, but they may be as light as classical axion miniclusters, of the order of 10{sup -12}M{sub {center_dot}}. We simulate the formation and nonlinear gravitational collapse of these objects around matter-radiation equality using an N-body code, estimate their gravitational lensing properties, and assess the feasibility of studying them using current and future lensing experiments. Future MACHO-type variability surveys of many background sources can reveal either high-amplification, strong-lensing events, or measure density profiles directly via weak-lensing variability, depending on ScaM parameters and survey depth. However, ScaMs, due to their low internal densities, are unlikely to be responsible for apparent MACHO events already detected in the Galactic halo. As a result, in the entire window between 10{sup -7}M{sub {center_dot}} and 10{sup 2}M{sub {center_dot}} covered by the galactic scale lensing experiments, ScaMs may in fact compose all the dark matter. A simple estimate is made of parameters that would give rise to early structure formation; in principle, early stellar collapse could be triggered by ScaMs as early as recombination, and significantly affect cosmic reionization.

  2. Scalar mesons and polarizability of the nucleon

    SciTech Connect

    Schumacher, Martin

    2008-08-31

    It is shown that the scalar mesons {sigma}, f{sub 0}(980) and a{sub 0}(980) as t-channel exchanges quantitatively solve the problem of diamagnetism and give an explanation of the large missing part of the electric polarizability {alpha} showing up when only the pion cloud is taken into account. The electric polarizability of the proton {alpha}{sub p} confirms a two-photon width of the {sigma} meson of {gamma}{sub {sigma}}{sub {gamma}}{sub {gamma}} = (2.58{+-}0.26) keV.

  3. Scalar wave diffraction from a circular aperture

    SciTech Connect

    Cerjan, C.

    1995-01-25

    The scalar wave theory is used to evaluate the expected diffraction patterns from a circular aperture. The standard far-field Kirchhoff approximation is compared to the exact result expressed in terms of oblate spheroidal harmonics. Deviations from an expanding spherical wave are calculated for circular aperture radius and the incident beam wavelength using suggested values for a recently proposed point diffractin interferometer. The Kirchhoff approximation is increasingly reliable in the far-field limit as the aperture radius is increased, although significant errors in amplitude and phase persist.

  4. Modeling dynamical scalarization with a resummed post-Newtonian expansion

    NASA Astrophysics Data System (ADS)

    Sennett, Noah; Buonanno, Alessandra

    2016-06-01

    Despite stringent constraints set by astrophysical observations, there remain viable scalar-tensor theories that could be distinguished from general relativity with gravitational-wave detectors. A promising signal predicted in these alternative theories is dynamical scalarization, which can dramatically affect the evolution of neutron-star binaries near merger. Motivated by the successful treatment of spontaneous scalarization, we develop a formalism that partially resums the post-Newtonian expansion to capture dynamical scalarization in a mathematically consistent manner. We calculate the post-Newtonian order corrections to the equations of motion and scalar mass of a binary system. Through comparison with quasiequilibrium configuration calculations, we verify that this new approximation scheme can accurately predict the onset and magnitude of dynamical scalarization.

  5. Study of Several Potentials as Scalar Field Dark Matter Candidates

    SciTech Connect

    Matos, Tonatiuh; Vazquez-Gonzalez, Alberto; Magan a, Juan

    2008-12-04

    In this work we study several scalar field potentials as a plausible candidate to be the dark matter in the universe. The main idea is the following; if the scalar field is an ultralight boson particle, it condensates like a Bose-Einstein system at very early times and forms the basic structure of the Universe. Real scalar fields collapse in equilibrium configurations which oscillate in space-time (oscillatons). The cosmological behavior of the field equations are solved using the dynamical system formalism. We use the current cosmological parameters as constraints for the free parameters of the scalar field potentials. We are able to reproduce very well the cosmological predictions of the standard {lambda}CDM model with some scalar field potentials. Therefore, scalar field dark matter seems to be a good alternative to be the nature of the dark matter of the universe.

  6. Passive scalar transport in peripheral regions of random flows

    SciTech Connect

    Chernykh, A.; Lebedev, V.

    2011-08-15

    We investigate statistical properties of the passive scalar mixing in random (turbulent) flows assuming its diffusion to be weak. Then at advanced stages of the passive scalar decay, its unmixed residue is primarily concentrated in a narrow diffusive layer near the wall and its transport to the bulk goes through the peripheral region (laminar sublayer of the flow). We conducted Lagrangian numerical simulations of the process for different space dimensions d and revealed structures responsible for the transport, which are passive scalar tongues pulled from the diffusive boundary layer to the bulk. We investigated statistical properties of the passive scalar and of the passive scalar integrated along the wall. Moments of both objects demonstrate scaling behavior outside the diffusive boundary layer. We propose an analytic scheme for the passive scalar statistics, explaining the features observed numerically.

  7. Exact scalar-tensor cosmological solutions via Noether symmetry

    NASA Astrophysics Data System (ADS)

    Belinchón, J. A.; Harko, T.; Mak, M. K.

    2016-02-01

    In this paper, we investigate the Noether symmetries of a generalized scalar-tensor, Brans-Dicke type cosmological model, in which we consider explicit scalar field dependent couplings to the Ricci scalar, and to the scalar field kinetic energy, respectively. We also include the scalar field self-interaction potential into the gravitational action. From the condition of the vanishing of the Lie derivative of the gravitational cosmological Lagrangian with respect to a given vector field we obtain three cosmological solutions describing the time evolution of a spatially flat Friedman-Robertson-Walker Universe filled with a scalar field. The cosmological properties of the solutions are investigated in detail, and it is shown that they can describe a large variety of cosmological evolutions, including models that experience a smooth transition from a decelerating to an accelerating phase.

  8. Scalar dissipation rate statistics in turbulent swirling jets

    NASA Astrophysics Data System (ADS)

    Stetsyuk, V.; Soulopoulos, N.; Hardalupas, Y.; Taylor, A. M. K. P.

    2016-07-01

    The scalar dissipation rate statistics were measured in an isothermal flow formed by discharging a central jet in an annular stream of swirling air flow. This is a typical geometry used in swirl-stabilised burners, where the central jet is the fuel. The flow Reynolds number was 29 000, based on the area-averaged velocity of 8.46 m/s at the exit and the diameter of 50.8 mm. The scalar dissipation rate and its statistics were computed from two-dimensional imaging of the mixture fraction fields obtained with planar laser induced fluorescence of acetone. Three swirl numbers, S, of 0.3, 0.58, and 1.07 of the annular swirling stream were considered. The influence of the swirl number on scalar mixing, unconditional, and conditional scalar dissipation rate statistics were quantified. A procedure, based on a Wiener filter approach, was used to de-noise the raw mixture fraction images. The filtering errors on the scalar dissipation rate measurements were up to 15%, depending on downstream positions from the burner exit. The maximum of instantaneous scalar dissipation rate was found to be up to 35 s-1, while the mean dissipation rate was 10 times smaller. The probability density functions of the logarithm of the scalar dissipation rate fluctuations were found to be slightly negatively skewed at low swirl numbers and almost symmetrical when the swirl number increased. The assumption of statistical independence between the scalar and its dissipation rate was valid for higher swirl numbers at locations with low scalar fluctuations and less valid for low swirl numbers. The deviations from the assumption of statistical independence were quantified. The conditional mean of the scalar dissipation rate, the standard deviation of the scalar dissipation rate fluctuations, the weighted probability of occurrence of the mean conditional scalar dissipation rate, and the conditional probability are reported.

  9. Quantum tunneling from scalar fields in rotating black strings

    NASA Astrophysics Data System (ADS)

    Gohar, H.; Saifullah, K.

    2013-08-01

    Using the Hamilton-Jacobi method of quantum tunneling and complex path integration, we study Hawking radiation of scalar particles from rotating black strings. We discuss tunneling of both charged and uncharged scalar particles from the event horizons. For this purpose, we use the Klein-Gordon equation and find the tunneling probability of outgoing scalar particles. The procedure gives Hawking temperature for rotating charged black strings as well.

  10. Black hole accretion discs and screened scalar hair

    NASA Astrophysics Data System (ADS)

    Davis, Anne-Christine; Gregory, Ruth; Jha, Rahul

    2016-10-01

    We present a novel way to investigate scalar field profiles around black holes with an accretion disc for a range of models where the Compton wavelength of the scalar is large compared to other length scales. By analysing the problem in ``Weyl" coordinates, we are able to calculate the scalar profiles for accretion discs in the static Schwarzschild, as well as rotating Kerr, black holes. We comment on observational effects.

  11. Complete NLO QCD corrections for tree level Δ F = 2 FCNC processes: colourless gauge bosons and scalars

    NASA Astrophysics Data System (ADS)

    Buras, Andrzej J.; Girrbach, Jennifer

    2012-03-01

    Anticipating the important role of tree level FCNC processes in the indirect search for new physics at distance scales as short as 10-19 - 10-21 m, we present complete NLO QCD corrections to tree level Δ F = 2 processes mediated by heavy colourless gauge bosons and scalars. Such contributions can be present at the fundamental level when the GIM mechanism is absent as in numerous Z' models, gauged flavour models with new very heavy neutral gauge bosons and Left-Right symmetric models with heavy neutral scalars. They can also be generated at one loop in models having GIM at the fundamental level and Minimal Flavour Violation of which Two-Higgs Doublet models with and without supersymmetry are the best known examples. In models containing vectorial heavy fermions that mix with the standard chiral quarks and models in which Z 0 and SM neutral Higgs H 0 mix with new heavy gauge bosons and scalars in the process of electroweak symmetry breaking also tree-level Z 0 and SM neutral Higgs H 0 contributions to Δ F = 2 processes are possible. In all these extensions new local operators absent in the SM are generated having Wilson coefficients that are generally much stronger affected by renormalization group QCD effects than it is the case of the SM operators. The new aspect of our work is the calculation of O( α s ) corrections to matching conditions for the Wilson coefficients of the contributing operators in the {text{NDR}} - overline {text{MS}} scheme that can be used in all models listed above. This allows to reduce certain unphysical scale and renormalization scheme dependences in the existing NLO calculations. We show explicitly how our results can be combined with the analytic formulae for the so-called P_i^a QCD factors that include both hadronic matrix elements of contributing operators and renormalization group evolution from high energy to low energy scales. For the masses of heavy gauge bosons and scalars O(1) TeV the remaining unphysical scale dependences for

  12. Kerr-Newman black holes with scalar hair

    NASA Astrophysics Data System (ADS)

    Delgado, Jorge F. M.; Herdeiro, Carlos A. R.; Radu, Eugen; Rúnarsson, Helgi

    2016-10-01

    We construct electrically charged Kerr black holes (BHs) with scalar hair. Firstly, we take an uncharged scalar field, interacting with the electromagnetic field only indirectly, via the background metric. The corresponding family of solutions, dubbed Kerr-Newman BHs with ungauged scalar hair, reduces to (a sub-family of) Kerr-Newman BHs in the limit of vanishing scalar hair and to uncharged rotating boson stars in the limit of vanishing horizon. It adds one extra parameter to the uncharged solutions: the total electric charge. This leading electromagnetic multipole moment is unaffected by the scalar hair and can be computed by using Gauss's law on any closed 2-surface surrounding (a spatial section of) the event horizon. By contrast, the first sub-leading electromagnetic multipole - the magnetic dipole moment -, gets suppressed by the scalar hair, such that the gyromagnetic ratio is always smaller than the Kerr-Newman value (g = 2). Secondly, we consider a gauged scalar field and obtain a family of Kerr-Newman BHs with gauged scalar hair. The electrically charged scalar field now stores a part of the total electric charge, which can only be computed by applying Gauss' law at spatial infinity and introduces a new solitonic limit - electrically charged rotating boson stars. In both cases, we analyze some physical properties of the solutions.

  13. Black hole hair in generalized scalar-tensor gravity.

    PubMed

    Sotiriou, Thomas P; Zhou, Shuang-Yong

    2014-06-27

    The most general action for a scalar field coupled to gravity that leads to second-order field equations for both the metric and the scalar--Horndeski's theory--is considered, with the extra assumption that the scalar satisfies shift symmetry. We show that in such theories, the scalar field is forced to have a nontrivial configuration in black hole spacetimes, unless one carefully tunes away a linear coupling with the Gauss-Bonnet invariant. Hence, black holes for generic theories in this class will have hair. This contradicts a recent no-hair theorem which seems to have overlooked the presence of this coupling. PMID:25014801

  14. NEUTRON STAR STRUCTURE IN THE PRESENCE OF SCALAR FIELDS

    SciTech Connect

    Crawford, James P.; Kazanas, Demosthenes

    2009-08-20

    Motivated by the possible presence of scalar fields on cosmological scales, suggested by the recent measurement of the deceleration parameter by supernovae surveys, we present models of neutron star structure under the assumption that a scalar field makes a significant contribution to the stress energy momentum tensor, in addition to that made by the normal matter. To that end we solve the coupled Einstein-scalar field-hydrostatic balance equations to compute the effect of the presence of the scalar field on the neutron star structure. We find that the presence of the scalar field does change the structure of the neutron star, especially in cases of strong coupling between the scalar field and the matter density. We present the neutron star radius as a function of the matter-scalar field coupling constant for different values of the neutron star central density. The presence of the scalar field does affect both the maximum neutron star mass and its radius, the latter increasing with the value of the above coupling constant. Our results can provide limits to the scalar field-matter coupling through spectro-temporal observations of accreting or isolated neutron stars.

  15. Invariant slow-roll parameters in scalar-tensor theories

    NASA Astrophysics Data System (ADS)

    Kuusk, Piret; Rünkla, Mihkel; Saal, Margus; Vilson, Ott

    2016-10-01

    A general scalar-tensor theory can be formulated in different parametrizations that are related by a conformal rescaling of the metric and a scalar field redefinition. We compare formulations of slow-roll regimes in the Einstein and Jordan frames using quantities that are invariant under the conformal rescaling of the metric and transform as scalar functions under the reparametrization of the scalar field. By comparing spectral indices, calculated up to second order, we find that the frames are equivalent up to this order, due to the underlying assumptions.

  16. Scalar self-interactions loosen constraints from fifth force searches

    SciTech Connect

    Gubser, Steven S.; Khoury, Justin

    2004-11-15

    The mass of a scalar field mediating a fifth force is tightly constrained by experiments. We show, however, that adding a quartic self-interaction for such a scalar makes most tests much less constraining: the nonlinear equation of motion masks the coupling of the scalar to matter through the chameleon mechanism. We discuss consequences for fifth force experiments. In particular, we find that, with quartic coupling of order unity, a gravitational strength interaction with matter is allowed by current constraints. We show that our chameleon scalar field results in experimental signatures that could be detected through modest improvements of current laboratory set-ups.

  17. Inflationary solutions in the nonminimally coupled scalar field theory

    NASA Astrophysics Data System (ADS)

    Koh, Seoktae; Kim, Sang Pyo; Song, Doo Jong

    2005-08-01

    We study analytically and numerically the inflationary solutions for various type scalar potentials in the nonminimally coupled scalar field theory. The Hamilton-Jacobi equation is used to deal with nonlinear evolutions of inhomogeneous spacetimes and the long-wavelength approximation is employed to find the homogeneous solutions during an inflation period. The constraints that lead to a sufficient number of e-folds, a necessary condition for inflation, are found for the nonminimal coupling constant and initial conditions of the scalar field for inflation potentials. In particular, we numerically find an inflationary solution in the new inflation model of a nonminimal scalar field.

  18. Disentangling scalar coupling patterns by real-time SERF NMR.

    PubMed

    Gubensäk, Nina; Fabian, Walter M F; Zangger, Klaus

    2014-10-21

    Scalar coupling constants and signal splitting patterns in NMR spectra contain a wealth of short-range structural information. The extraction of these parameters from (1)H NMR spectra is often prohibited by simultaneous scalar coupling interactions with several other protons. Here we present a high-resolution NMR experiment where scalar coupling to only one selected signal is visible. All other couplings are removed from the spectrum. This real-time selectively refocused NMR experiment is achieved by spatially selective homonuclear broadband decoupling combined with selective refocusing during acquisition. It allows the unperturbed extraction of scalar coupling constants from the highly resolved acquisition dimension of NMR spectra.

  19. Black hole hair in generalized scalar-tensor gravity.

    PubMed

    Sotiriou, Thomas P; Zhou, Shuang-Yong

    2014-06-27

    The most general action for a scalar field coupled to gravity that leads to second-order field equations for both the metric and the scalar--Horndeski's theory--is considered, with the extra assumption that the scalar satisfies shift symmetry. We show that in such theories, the scalar field is forced to have a nontrivial configuration in black hole spacetimes, unless one carefully tunes away a linear coupling with the Gauss-Bonnet invariant. Hence, black holes for generic theories in this class will have hair. This contradicts a recent no-hair theorem which seems to have overlooked the presence of this coupling.

  20. Emergence of Lorentzian signature and scalar gravity

    SciTech Connect

    Girelli, F.; Liberati, S.; Sindoni, L.

    2009-02-15

    In recent years, a growing momentum has been gained by the emergent gravity framework. Within the latter, the very concepts of geometry and gravitational interaction are not seen as elementary aspects of nature but rather as collective phenomena associated to the dynamics of more fundamental objects. In this paper we want to further explore this possibility by proposing a model of emergent Lorentzian signature and scalar gravity. Assuming that the dynamics of the fundamental objects can give rise in first place to a Riemannian manifold and a set of scalar fields we show how time (in the sense of hyperbolic equations) can emerge as a property of perturbations dynamics around some specific class of solutions of the field equations. Moreover, we show that these perturbations can give rise to a spin-0 gravity via a suitable redefinition of the fields that identifies the relevant degrees of freedom. In particular, we find that our model gives rise to Nordstroem gravity. Since this theory is invariant under general coordinate transformations, this also shows how diffeomorphism invariance (albeit of a weaker form than the one of general relativity) can emerge from much simpler systems.

  1. Dynamical analysis in scalar field cosmology

    NASA Astrophysics Data System (ADS)

    Paliathanasis, Andronikos; Tsamparlis, Michael; Basilakos, Spyros; Barrow, John D.

    2015-06-01

    We give a general method to find exact cosmological solutions for scalar-field dark energy in the presence of perfect fluids. We use the existence of invariant transformations for the Wheeler De Witt (WdW) equation. We show that the existence of a point transformation under which the WdW equation is invariant is equivalent to the existence of conservation laws for the field equations, which indicates the existence of analytical solutions. We extend previous work by providing exact solutions for the Hubble parameter and the effective dark-energy equation of state parameter for cosmologies containing a combination of perfect fluid and a scalar field whose self-interaction potential is a power of hyperbolic functions. We find solutions explicitly when the perfect fluid is radiation or cold dark matter and determine the effects of nonzero spatial curvature. Using the Planck 2015 data, we determine the evolution of the effective equation of state of the dark energy. Finally, we study the global dynamics using dimensionless variables. We find that if the current cosmological model is Liouville integrable (admits conservation laws) then there is a unique stable point which describes the de-Sitter phase of the universe.

  2. Scalar field theory on noncommutative Snyder spacetime

    SciTech Connect

    Battisti, Marco Valerio; Meljanac, Stjepan

    2010-07-15

    We construct a scalar field theory on the Snyder noncommutative space-time. The symmetry underlying the Snyder geometry is deformed at the co-algebraic level only, while its Poincare algebra is undeformed. The Lorentz sector is undeformed at both the algebraic and co-algebraic level, but the coproduct for momenta (defining the star product) is non-coassociative. The Snyder-deformed Poincare group is described by a non-coassociative Hopf algebra. The definition of the interacting theory in terms of a nonassociative star product is thus questionable. We avoid the nonassociativity by the use of a space-time picture based on the concept of the realization of a noncommutative geometry. The two main results we obtain are (i) the generic (namely, for any realization) construction of the co-algebraic sector underlying the Snyder geometry and (ii) the definition of a nonambiguous self-interacting scalar field theory on this space-time. The first-order correction terms of the corresponding Lagrangian are explicitly computed. The possibility to derive Noether charges for the Snyder space-time is also discussed.

  3. Searching for Chameleon-Like Scalar Fields

    NASA Astrophysics Data System (ADS)

    Levshakov, S. A.; Molaro, P.; Kozlov, M. G.; Lapinov, A. V.; Henkel, Ch.; Reimersi, D.; Sakai, T.; Agafonova, I. I.

    Using the 32-m Medicina, 45-m Nobeyama, and 100-m Effelsberg telescopes we found a statistically significant velocity offset ΔV ≈ 27 ± 3 m s - 1 (1σ) between the inversion transition in NH3(1,1) and low-J rotational transitions in N2H + (1-0) and HC3N(2-1) arising in cold and dense molecular cores in the Milky Way. Systematic shifts of the line centers caused by turbulent motions and velocity gradients, possible non-thermal hyperfine structure populations, pressure and optical depth effects are shown to be lower than or about 1 m s - 1 and thus can be neglected in the total error budget. The reproducibility of ΔV at the same facility (Effelsberg telescope) on a year-to-year basis is found to be very good. Since the frequencies of the inversion and rotational transitions have different sensitivities to variations in μ ≡ m e / m p, the revealed non-zero ΔV may imply that μ changes when measured at high (terrestrial) and low (interstellar) matter densities as predicted by chameleon-like scalar field models - candidates to the dark energy carrier. Thus we are testing whether scalar field models have chameleon-type interactions with ordinary matter. The measured velocity offset corresponds to the ratio Δμ / μ ≡ (μspace - μlab) / μlab of (26 ± 3) ×10 - 9 (1σ).

  4. Infrared detection of (H2O)20 isomers of exceptional stability: A drop-like and a face-sharing pentagonal prism cluster

    DOE PAGES

    Pradzynski, Christoph C.; Dierking, Christoph W.; Zurheide, Florian; Forck, Richard M.; Buck, Udo; Zeuch, Thomas; Xantheas, Sotiris S.

    2014-09-01

    Water clusters containing fully coordinated water molecules are model systems that mimic the local environment of the condensed phase. Present knowledge about the water cluster size regime in which the transition from the allsurface to the fully solvated water molecules occurs is mainly based on theoretical predictions in lieu of the absence of precisely size resolved experimental measurements. Here, we report size and isomer selective infrared (IR) spectra of (H2O)20 clusters tagged with a sodium atom by employing IR excitation modulated photoionization spectroscopy. The observed absorption patterns in the OH stretching ”fingerprint” region are consistent with the theoretically predicted spectramore » of two structurally distinct isomers: A drop-like cluster with a fully coordinated (interior) water and an edge-sharing pentagonal prism cluster in which all atoms are on the surface. The observed isomers show exceptional stability and are predicted to be nearly isoenergetic.« less

  5. Simple Method for Constructing RNA Triangle, Square, Pentagon by Tuning Interior RNA 3WJ Angle from 60° to 90° or 108°.

    PubMed

    Khisamutdinov, Emil F; Bui, My Nguyen Hoan; Jasinski, Daniel; Zhao, Zhengyi; Cui, Zheng; Guo, Peixuan

    2015-01-01

    Precise shape control of architectures at the nanometer scale is an intriguing but extremely challenging facet. RNA has recently emerged as a unique material and thermostable building block for use in nanoparticle construction. Here, we describe a simple method from design to synthesis of RNA triangle, square, and pentagon by stretching RNA 3WJ native angle from 60° to 90° and 108°, using the three-way junction (3WJ) of the pRNA from bacteriophage phi29 dsDNA packaging motor. These methods for the construction of elegant polygons can be applied to other RNA building blocks including the utilization and application of RNA 4-way, 5-way, and other multi-way junctions.

  6. Workshop on models to estimate military system probability of effect (P/sub E/) due to incident radiofrequency energy: Volume 2, Proceedings: The Pentagon

    SciTech Connect

    Chesser, N.J.

    1988-01-01

    The material which follows summarizes the presentations and discussion which took place during a workshop held at the Pentagon in June 1988. The first five sections are summaries of individual presentations, not strictly in the order in which they were given, but rather divided into five topic areas and arranged within those areas in the order in which they were presented: Introduction; Proposed Approaches to P/sub K/; Methods from SDI LTH; Lessons from the EMP/EMI/EMC Community; HPM Testing Methodology. Where appropriate, comments made during those presentations are noted within curly brackets /l brace/.../r brace/. Section Six summarizes the observations made and issues raised during the working session on the afternoon of the second day.

  7. Simple Method for Constructing RNA Triangle, Square, Pentagon by Tuning Interior RNA 3WJ Angle from 60° to 90° or 108°.

    PubMed

    Khisamutdinov, Emil F; Bui, My Nguyen Hoan; Jasinski, Daniel; Zhao, Zhengyi; Cui, Zheng; Guo, Peixuan

    2015-01-01

    Precise shape control of architectures at the nanometer scale is an intriguing but extremely challenging facet. RNA has recently emerged as a unique material and thermostable building block for use in nanoparticle construction. Here, we describe a simple method from design to synthesis of RNA triangle, square, and pentagon by stretching RNA 3WJ native angle from 60° to 90° and 108°, using the three-way junction (3WJ) of the pRNA from bacteriophage phi29 dsDNA packaging motor. These methods for the construction of elegant polygons can be applied to other RNA building blocks including the utilization and application of RNA 4-way, 5-way, and other multi-way junctions. PMID:25967062

  8. Comparison of geometric, electronic, and vibrational properties for all pentagon/hexagon-bearing isomers of fullerenes C38, C40, and C42

    NASA Astrophysics Data System (ADS)

    Małolepsza, Edyta; Lee, Yuan-Pern; Witek, Henryk A.; Irle, Stephan; Lin, Chun-Fu; Hsieh, Horng-Ming

    The self-consistent-charge density-functional tight-binding (SCC-DFTB) method is employed for computing geometric, electronic, and vibrational properties for various topological isomers of small fullerenes. We consider all pentagon/hexagon-bearing isomers of C38, C40, and C42 as the second part of a larger effort to catalogue the CC distance distributions, valence CCC angle distributions, electronic densities of states (DOSs), vibrational densities of states (VDOSs), and infrared (IR) and Raman spectra for fullerenes C20=C180 [analogous data for C20=C36 were published previously in Małolepsza et al., J Phys Chem A, 2007, 111, 6649]. Common features among the fullerenes are identified and properties characteristic for each specific fullerene cage size are discussed.

  9. A new scalar resonance at 750 GeV: towards a proof of concept in favor of strongly interacting theories

    NASA Astrophysics Data System (ADS)

    Son, Minho; Urbano, Alfredo

    2016-05-01

    We interpret the recently observed excess in the diphoton invariant mass as a new spin-0 resonant particle. On theoretical grounds, an interesting question is whether this new scalar resonance belongs to a strongly coupled sector or a well-defined weakly coupled theory. A possible UV-completion that has been widely considered in literature is based on the existence of new vector-like fermions whose loop contributions — Yukawa-coupled to the new resonance — explain the observed signal rate. The large total width preliminarily suggested by data seems to favor a large Yukawa coupling, at the border of a healthy perturbative definition. This potential problem can be fixed by introducing multiple vector-like fermions or large electric charges, bringing back the theory to a weakly coupled regime. However, this solution risks to be only a low-energy mirage: large multiplicity or electric charge can dangerously reintroduce the strong regime by modifying the renormalization group running of the dimensionless couplings. This issue is also tightly related to the (in)stability of the scalar potential. First, we study — in the theoretical setup described above — the parametric behavior of the diphoton signal rate, total width, and one-loop β functions. Then, we numerically solve the renormalization group equations, taking into account the observed diphoton signal rate and total width, to investigate the fate of the weakly coupled theory. We find that — with the only exception of few fine-tuned directions — weakly coupled interpretations of the excess are brought back to a strongly coupled regime if the running is taken into account.

  10. Semi-analytic stellar structure in scalar-tensor gravity

    NASA Astrophysics Data System (ADS)

    Horbatsch, M. W.; Burgess, C. P.

    2011-08-01

    Precision tests of gravity can be used to constrain the properties of hypothetical very light scalar fields, but these tests depend crucially on how macroscopic astrophysical objects couple to the new scalar field. We study the equations of stellar structure using scalar-tensor gravity, with the goal of seeing how stellar properties depend on assumptions made about the scalar coupling at a microscopic level. In order to make the study relatively easy for different assumptions about microscopic couplings, we develop quasi-analytic approximate methods for solving the stellar-structure equations rather than simply integrating them numerically. (The approximation involved assumes the dimensionless scalar coupling at the stellar center is weak, and we compare our results with numerical integration in order to establish its domain of validity.) We illustrate these methods by applying them to Brans-Dicke scalars, and their generalization in which the scalar-matter coupling slowly runs — or `walks' — as a function of the scalar field: a(phi) simeq as+bsphi. (Such couplings can arise in extra-dimensional applications, for instance.) The four observable parameters that characterize the fields external to a spherically symmetric star are the stellar radius, R, mass, M, scalar `charge', Q, and the scalar's asymptotic value, phi∞. These are subject to two relations because of the matching to the interior solution, generalizing the usual mass-radius, M(R), relation of General Relativity. Since phi∞ is common to different stars in a given region (such as a binary pulsar), all quantities can be computed locally in terms of the stellar masses. We identify how these relations depend on the microscopic scalar couplings, agreeing with earlier workers when comparisons are possible. Explicit analytical solutions are obtained for the instructive toy model of constant-density stars, whose properties we compare to more realistic equations of state for neutron star models.

  11. High pressure synthesis and properties of ternary titanium (III) fluorides in the system KF-TiF{sub 3} containing regular pentagonal bipyramids [TiF{sub 7}

    SciTech Connect

    Yamanaka, Shoji; Yasuda, Akira; Miyata, Hajime

    2010-01-15

    Titanium trifluoride TiF{sub 3} has the distorted ReO{sub 3} structure composed of corner sharing TiF{sub 6} octahedra linked with Ti-F-Ti bridges. Potassium fluoride KF was inserted into the bridges using high-pressure and high-temperature conditions (5 GPa, 1000-1200 deg. C). When the molar ratio KF/TiF{sub 3}>=1, a few low dimensional compounds were obtained forming non-bridged F ions. At the composition KF/TiF{sub 3}=1/2, a new compound KTi{sub 2}F{sub 7} was formed, which crystallizes with the space group Cmmm and the lattice parameters of a=6.371(3), b=10.448(6), c=3.958(2) A, consisting of edge-sharing pentagonal bipyramids [TiF{sub 7}] forming ribbons running along the a axis. The ribbons are linked by corners to construct a three-dimensional framework without forming non-bridged F ions. The compound is antiferromagnetic with the Neel temperature T{sub N}=75 K, and the optical band gap was 6.4 eV. A new fluoride K{sub 2}TiF{sub 5} (KF/TiF{sub 3}=2) with the space group Pbcn and the lattice parameters of a=7.4626(2), b=12.9544(4) and c=20.6906(7) A was also obtained by the high pressure and high temperature treatment (5 GPa at 1000 deg. C) of a molar mixture of 2 KF+TiF{sub 3}. The compound contains one-dimensional chains of corner-sharing TiF{sub 6} octahedra. - Graphical Abstract: A new ternary fluoride KTi{sub 2}F{sub 7} has been developed under high-pressure and high-temperature conditions, which contains pentagonal bipyramid polyhedra [TiF{sub 7}].

  12. Symmetric scalar constraint for loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Lewandowski, Jerzy; Sahlmann, Hanno

    2015-02-01

    In the framework of loop quantum gravity, we define a new Hilbert space of states which are solutions of a large number of components of the diffeomorphism constraint. On this Hilbert space, using the methods of Thiemann, we obtain a family of gravitational scalar constraints. They preserve the Hilbert space for every choice of lapse function. Thus adjointness and commutator properties of the constraint can be investigated in a straightforward manner. We show how the space of solutions of the symmetrized constraint can be defined by spectral decomposition, and the Hilbert space of physical states by subsequently fully implementing the diffeomorphism constraint. The relationship of the solutions to those resulting from a proposal for a symmetric constraint operator by Thiemann remains to be elucidated.

  13. Visualization of Scalar Adaptive Mesh Refinement Data

    SciTech Connect

    VACET; Weber, Gunther; Weber, Gunther H.; Beckner, Vince E.; Childs, Hank; Ligocki, Terry J.; Miller, Mark C.; Van Straalen, Brian; Bethel, E. Wes

    2007-12-06

    Adaptive Mesh Refinement (AMR) is a highly effective computation method for simulations that span a large range of spatiotemporal scales, such as astrophysical simulations, which must accommodate ranges from interstellar to sub-planetary. Most mainstream visualization tools still lack support for AMR grids as a first class data type and AMR code teams use custom built applications for AMR visualization. The Department of Energy's (DOE's) Science Discovery through Advanced Computing (SciDAC) Visualization and Analytics Center for Enabling Technologies (VACET) is currently working on extending VisIt, which is an open source visualization tool that accommodates AMR as a first-class data type. These efforts will bridge the gap between general-purpose visualization applications and highly specialized AMR visual analysis applications. Here, we give an overview of the state of the art in AMR scalar data visualization research.

  14. A broad-band scalar vortex coronagraph

    NASA Astrophysics Data System (ADS)

    Errmann, R.; Minardi, S.; Pertsch, T.

    2013-10-01

    Broad-band coronagraphy with deep nulling and small inner working angle has the potential of delivering images and spectra of exoplanets and other faint objects. In recent years, many coronagraphic schemes have been proposed, the most promising being the optical vortex phase mask coronagraphs. In this paper, a new scheme of broad-band optical scalar vortex coronagraph is proposed and characterized experimentally in the laboratory. Our setup employs a pair of computer-generated phase gratings (one of them containing a singularity) to control the chromatic dispersion of phase plates and achieves a constant peak-to-peak attenuation below 1 × 10-3 over a bandwidth of 120 nm centred at 700 nm. An inner working angle of ˜λ/D is demonstrated along with a raw contrast of 11.5 mag at 2λ/D.

  15. A broadband scalar optical vortex coronagraph

    NASA Astrophysics Data System (ADS)

    Errmann, Ronnie; Minardi, Stefano; Pertsch, Thomas

    2014-07-01

    In recent years, new coronagraphic schemes have been proposed, the most promising being the optical vortex phase mask coronagraphs. In our work, a new scheme of broadband optical scalar vortex coronagraph is proposed and characterized experimentally in the laboratory. Our setup employs a pair of computer generated phase gratings (one of them containing a singularity) to control the chromatic dispersion of phase plates and achieves a constant peak-to-peak attenuation below 1:1000 over a bandwidth of 120 nm centered at 700 nm. An inner working angle of λ/D is demonstrated along with a raw contrast of 11.5magnitudes at 2λ/D. A more compact setup achieves a peak-to-peak attenuation below 1:1000 over a bandwidth of 60 nm with the other results remaining the same.

  16. Light scalar susceptibilities and isospin breaking

    SciTech Connect

    Andres, R. Torres; Nicola, A. Gomez

    2010-12-28

    Making a thermal analysis in the context of NLO SU(3) Chiral Perturbation Theory we see that isospin breaking (IB) corrections (both electromagnetic and QCD ones) to quark condensates are of order O(e{sup 2}) and O({epsilon}), with {epsilon} the {pi}{sup 0}-{eta} mixing angle. However the combination {chi}{sub uu}-{chi}{sub ud} of flavour breaking susceptibilities, which vanishes in the isospin limit and can be identified essentially with the connected susceptibility, has an order O(1) contribution enhanced with T because of the {pi}{sup 0}-{eta}) mixing. Finally we present a thermal sum rule that relates quark condensate ratios and the light scalar susceptibility without IB, {chi}(T)-{chi}(0).

  17. Gauge Fields, Scalars, Warped Geometry, and Strings

    SciTech Connect

    Silverstein, Eva M

    2000-12-07

    We review results on several interesting phenomena in warped compactifications of M theory, as presented at Strings 2000. The behavior of gauge fields in dimensional reduction from d + 1 to d dimensions in various backgrounds is explained from the point of view of the holographic duals (and a point raised in the question session at the conference is addressed). We summarize the role of additional fields (in particular scalar fields) in 5d warped geometries in making it possible for Poincare-invariant domain wall solutions to exist to a nontrivial order in a controlled approximation scheme without fine-tuning of parameters in the 5d action (and comment on the status of the singularities arising in the general relativistic description of these solutions). Finally, we discuss briefly the emergence of excitations of wrapped branes in warped geometries whose effective thickness, as measured along the Poincare slices in the geometry, grows as the energy increases.

  18. Gastric cryptosporidiosis in freshwater angelfish (Pterophyllum scalare)

    USGS Publications Warehouse

    Murphy, B.G.; Bradway, D.; Walsh, T.; Sanders, G.E.; Snekvik, K.

    2009-01-01

    A freshwater angelfish (Pterophyllum scalare) hatchery experienced variable levels of emaciation, poor growth rates, swollen coelomic cavities, anorexia, listlessness, and increased mortality within their fish. Multiple chemotherapeutic trials had been attempted without success. In affected fish, large numbers of protozoa were identified both histologically and ultrastructurally associated with the gastric mucosa. The youngest cohort of parasitized fish was the most severely affected and demonstrated the greatest morbidity and mortality. The protozoa were morphologically most consistent with Cryptosporidium. All of the protozoan life stages were identified ultrastructurally and protozoal genomic DNA was isolated from parasitized tissue viscera and sequenced. Histological, ultrastructural, genetic, and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium.

  19. Relativistic stars in scalar-tensor theories with disformal coupling

    NASA Astrophysics Data System (ADS)

    Minamitsuji, Masato; Silva, Hector O.

    2016-06-01

    We present a general formulation to analyze the structure of slowly rotating relativistic stars in a broad class of scalar-tensor theories with disformal coupling to matter. Our approach includes theories with generalized kinetic terms, generic scalar field potentials and contains theories with conformal coupling as particular limits. In order to investigate how the disformal coupling affects the structure of relativistic stars, we propose a minimal model of a massless scalar-tensor theory and investigate in detail how the disformal coupling affects the spontaneous scalarization of slowly rotating neutron stars. We show that for negative values of the disformal coupling parameter between the scalar field and matter, scalarization can be suppressed, while for large positive values of the disformal coupling parameter stellar models cannot be obtained. This allows us to put a mild upper bound on this parameter. We also show that these properties can be qualitatively understood by linearizing the scalar field equation of motion in the background of a general-relativistic incompressible star. To address the intrinsic degeneracy between uncertainties in the equation of state of neutron stars and gravitational theory, we also show the existence of universal equation-of-state-independent relations between the moment of inertia and compactness of neutron stars in this theory. We show that in a certain range of the theory's parameter space the universal relation largely deviates from that of general relativity, allowing, in principle, to probe the existence of spontaneous scalarization with future observations.

  20. Renormalization group analysis in nonrelativistic QCD for colored scalars

    SciTech Connect

    Hoang, Andre H.; Ruiz-Femenia, Pedro

    2006-01-01

    The velocity nonrelativistic QCD Lagrangian for colored heavy scalar fields in the fundamental representation of QCD and the renormalization group analysis of the corresponding operators are presented. The results are an important ingredient for renormalization group improved computations of scalar-antiscalar bound state energies and production rates at next-to-next-to-leading-logarithmic (NNLL) order.

  1. On relation between scalar interfaces and vorticity in inviscid flows

    NASA Astrophysics Data System (ADS)

    Ramesh, O. N.; Patwardhan, Saurabh

    2013-11-01

    A great variety of applications like pollutant mixing in the atmosphere, mixing of reactants in combustion highlight the importance of passive scalar dynamics in fluid flows. The other dynamically important variable in the study of fluid flow is the vorticity. Vorticity though, unlike a passive scalar, does affect the fluid motion. The dynamics of scalar (linear) and vorticity (non-linear) are governed by the equations which inherently have different characteristics. This paper addresses the question of the faithfulness of representation of vorticity by scalar marker and the motivation for this comes from the experiment of Head and Bandyopadhyay (1981) which showed the existence of coherent vortices by using smoke flow visualization in a turbulent boundary layer. We will show analytically in regions where the molecular diffusion effects are negligible, the vorticity and scalar gradients are orthogonal to each other. The iso- surface of scalar follows the vorticity in an inviscid situation. Also, we will demonstrate that in the case of unsteady burgers vortex and vortex shedding behind a finite circular cylinder, the scalar gradient is orthogonal to vorticity and inner product of vorticity and scalar gradients is zero in regions away from the wall.

  2. LIPSS results for photons coupling to light neutral scalar bosons

    SciTech Connect

    Andrei Afanasev; Oliver K. Baker; Kevin Beard; George Biallas; James Boyce; Minarni Minarni; Roopchan Ramdon; Michelle D. Shinn; Penny Slocum

    2008-06-01

    The LIPSS search for a light neutral scalar boson coupling to optical photons is reported. The search covers a region of parameter space of approximately 1.0 meV and coupling strength greater than 10^-6 GeV^-1. The LIPSS results show no evidence for scalar coupling in this region of parameter space.

  3. When scalar field is kinetically coupled to the Einstein tensor

    SciTech Connect

    Gao, Changjun

    2010-06-01

    We explore the cosmic evolution of a scalar field with the kinetic term coupled to the Einstein tensor. We find that, in the absence of other matter sources or in the presence of only pressureless matter, the scalar behaves as pressureless matter and the sound speed of the scalar is vanishing. These properties enable the scalar field to be a candidate of cold dark matter. By also considering the scalar potential, we find the scalar field may play the role of both dark matter and dark energy. In this case, the equation of state of the scalar can cross the phantom divide, but this can lead to the sound speed becoming superluminal as it crosses the divide, and so is physically forbidden. Finally, if the kinetic term is coupled to more than one Einstein tensor, we find the equation of state is always approximately equal to -1 whether the potential is flat or not, and so the scalar may also be a candidate for the inflaton.

  4. Scalar field theory in {kappa}-Minkowski spacetime from twist

    SciTech Connect

    Kim, Hyeong-Chan; Lee, Youngone; Rim, Chaiho; Yee, Jae Hyung

    2009-10-15

    Using the twist deformation of U(igl(4,R)), the linear part of the diffeomorphism, we define a scalar function and construct a free scalar field theory in four-dimensional {kappa}-Minkowski spacetime. The action in momentum space turns out to differ only in the integration measure from the commutative theory.

  5. Search for scalar top and bottom quarks at the Tevatron

    SciTech Connect

    Calfayan, Philippe

    2008-11-23

    This document reviews recent results on the search for scalar top and scalar bottom quarks in pp-bar collisions at {radical}(s) = 1.96 TeV. The analyses presented are based on data samples with integrated luminosities from 1.0 to 1.9 fb{sup -1} recorded at the Tevatron with the D0 and CDF detectors.

  6. Emission of scalar particles from cylindrical black holes

    NASA Astrophysics Data System (ADS)

    Gohar, H.; Saifullah, K.

    2013-01-01

    We study quantum tunneling of scalar particles from black strings. For this purpose we apply WKB approximation and Hamilton-Jacobi method to solve the Klein-Gordon equation for outgoing trajectories. We find the tunneling probability of outgoing charged and uncharged scalars from the event horizon of black strings, and hence the Hawking temperature for these black configurations.

  7. Scalar triplet flavored leptogenesis: a systematic approach

    SciTech Connect

    Sierra, D. Aristizabal; Dhen, Mikaël; Hambye, Thomas E-mail: mikadhen@ulb.ac.be

    2014-08-01

    Type-II seesaw is a simple scenario in which Majorana neutrino masses are generated by the exchange of a heavy scalar electroweak triplet. When endowed with additional heavy fields, such as right-handed neutrinos or extra triplets, it also provides a compelling framework for baryogenesis via leptogenesis. We derive in this context the full network of Boltzmann equations for studying leptogenesis in the flavored regime. To this end we determine the relations which hold among the chemical potentials of the various particle species in the thermal bath. This takes into account the standard model Yukawa interactions of both leptons and quarks as well as sphaleron processes which, depending on the temperature, may be classified as faster or slower than the Universe Hubble expansion. We find that when leptogenesis is enabled by the presence of an extra triplet, lepton flavor effects allow the production of the B-L asymmetry through lepton number conserving CP asymmetries. This scenario becomes dominant as soon as the triplets couple more to leptons than to standard model scalar doublets. In this case, the way the B-L asymmetry is created through flavor effects is novel: instead of invoking the effect of L-violating inverse decays faster than the Hubble rate, it involves the effect of L-violating decays slower than the Hubble rate. We also analyze the more general situation where lepton number violating CP asymmetries are present and actively participate in the generation of the B-L asymmetry, pointing out that as long as L-violating triplet decays are still in thermal equilibrium when the triplet gauge scattering processes decouple, flavor effects can be striking, allowing to avoid all washout suppression effects from seesaw interactions. In this case the amount of B-L asymmetry produced is limited only by a universal gauge suppression effect, which nevertheless goes away for large triplet decay rates.

  8. Simultaneous timing of multiple intervals: implications of the scalar property.

    PubMed

    Leak, T M; Gibbon, J

    1995-01-01

    Three experiments with pigeons are reported in which the scalar property in simultaneous timing tasks was studied. According to scalar expectancy theory, the scalar property should be maintained in simultaneous timing, but the behavioral theory of timing predicts that the scalar property should be evident only in independent timing. Experiment 1 showed that the appearance of distinct peaks at reinforcement times required about a 4:1 ratio between intervals. Experiment 2 (2-interval timing task) and Experiment 3 (3-interval timing task) used an individual trial analysis technique to examine high-rate responding segments bracketing the times of reinforcement. The standard deviations of the starting and stopping times of high-rate segments were linearly related to their means and to reinforcement time, supporting the scalar property in simultaneous timing.

  9. Involvement of prefrontal cortex in scalar implicatures: evidence from magnetoencephalography

    PubMed Central

    Politzer-Ahles, Stephen; Gwilliams, Laura

    2015-01-01

    The present study investigated the neural correlates of the realisation of scalar inferences, i.e., the interpretation of some as meaning some but not all. We used magnetoencephalography, which has high temporal resolution, to measure neural activity while participants heard stories that included the scalar inference trigger some in contexts that either provide strong cues for a scalar inference or provide weaker cues. The middle portion of the lateral prefrontal cortex (Brodmann area 46) showed an increased response to some in contexts with fewer cues to the inference, suggesting that this condition elicited greater effort. While the results are not predicted by traditional all-or-nothing accounts of scalar inferencing that assume the process is always automatic or always effortful, they are consistent with more recent gradient accounts which predict that the speed and effort of scalar inferences is strongly modulated by numerous contextual factors. PMID:26247054

  10. Scalar Hair of Global Defect and Black Brane World

    NASA Astrophysics Data System (ADS)

    Kim, Yoonbai; Park, Dong Hyun

    2004-06-01

    We consider a complex scalar field in (p+3)-dimensional bulk with a negative cosmological constant and study global vortices in two extra-dimensions. We reexamine carefully the coupled scalar and Einstein equations, and show that the boundary value of scalar amplitude at infinity of the extra-dimensions should be smaller than vacuum expectation value. The brane world has a cigar-like geometry with an exponentially decaying warp factor and a flat thick p-brane is embedded. Since a coordinate transformation identifies the obtained brane world as a black p-brane world bounded by a horizon, this strange boundary condition of the scalar amplitude is understood as existence of a short scalar hair.

  11. Screening of heavy scalars beyond the standard model

    SciTech Connect

    Einhorn, M.B. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 ); Wudka, J. )

    1993-06-01

    Spontaneously broken gauge models generically present large radiative corrections when the masses of the scalars are larger than the symmetry-breaking scale(s). This is not necessary, however, and we determine, based on the symmetry and renormalization properties of the theory, the most general conditions under which scalar radiative effects are screened. Barring fine tuning, the properties of the Goldstone sector determine whether this type of screening is present or not, and this can be decided in most cases by inspection (given the pattern of symmetry breaking). We consider several examples. In particular we show that in left-right symmetric models the two requirements that all scalars be significantly heavier than the gauge bosons is inconsistent with screening; this implies either the presence of large radiative corrections produced by the heavy scalars, or the presence of scalars with masses similar to that of the (heaviest) gauge bosons in these models.

  12. Limits of scalar diffraction theory for conducting gratings.

    PubMed

    Gremaux, D A; Gallagher, N C

    1993-04-10

    Scalar diffraction theory and electromagnetic vector theory are compared by analyzing plane-wave scattering by a perfectly conducting, rectangular-grooved grating. General field solutions for arbitrary angles of incidence are derived by using scalar and vector theories. Diffraction efficiencies for the scalar and the vector cases as functions of wavelength, grating period, and angles of incidence are determined numerically and plotted. When the wavelength of the incident field is much shorter than the grating period, the diffraction efficiencies match. But when the wavelength is of the order of the grating period, large differences between the scalar and the vector solutions emerge. One general conclusion is that, depending on polarization, scalar theory should not be used when the grating period becomes smaller than ten wavelengths.

  13. Scalar Dissipation Modeling for Passive and Active Scalars: a priori Study Using Direct Numerical Simulation

    NASA Technical Reports Server (NTRS)

    Selle, L. C.; Bellan, Josette

    2006-01-01

    Transitional databases from Direct Numerical Simulation (DNS) of three-dimensional mixing layers for single-phase flows and two-phase flows with evaporation are analyzed and used to examine the typical hypothesis that the scalar dissipation Probability Distribution Function (PDF) may be modeled as a Gaussian. The databases encompass a single-component fuel and four multicomponent fuels, two initial Reynolds numbers (Re), two mass loadings for two-phase flows and two free-stream gas temperatures. Using the DNS calculated moments of the scalar-dissipation PDF, it is shown, consistent with existing experimental information on single-phase flows, that the Gaussian is a modest approximation of the DNS-extracted PDF, particularly poor in the range of the high scalar-dissipation values, which are significant for turbulent reaction rate modeling in non-premixed flows using flamelet models. With the same DNS calculated moments of the scalar-dissipation PDF and making a change of variables, a model of this PDF is proposed in the form of the (beta)-PDF which is shown to approximate much better the DNS-extracted PDF, particularly in the regime of the high scalar-dissipation values. Several types of statistical measures are calculated over the ensemble of the fourteen databases. For each statistical measure, the proposed (beta)-PDF model is shown to be much superior to the Gaussian in approximating the DNS-extracted PDF. Additionally, the agreement between the DNS-extracted PDF and the (beta)-PDF even improves when the comparison is performed for higher initial Re layers, whereas the comparison with the Gaussian is independent of the initial Re values. For two-phase flows, the comparison between the DNS-extracted PDF and the (beta)-PDF also improves with increasing free-stream gas temperature and mass loading. The higher fidelity approximation of the DNS-extracted PDF by the (beta)-PDF with increasing Re, gas temperature and mass loading bodes well for turbulent reaction rate

  14. Reaction enhancement of initially distant scalars by Lagrangian coherent structures

    SciTech Connect

    Pratt, Kenneth R. Crimaldi, John P.; Meiss, James D.

    2015-03-15

    Turbulent fluid flows have long been recognized as a superior means of diluting initial concentrations of scalars due to rapid stirring. Conversely, experiments have shown that the structures responsible for this rapid dilution can also aggregate initially distant reactive scalars and thereby greatly enhance reaction rates. Indeed, chaotic flows not only enhance dilution by shearing and stretching but also organize initially distant scalars along transiently attracting regions in the flow. To show the robustness of this phenomenon, a hierarchical set of three numerical flows is used: the periodic wake downstream of a stationary cylinder, a chaotic double gyre flow, and a chaotic, aperiodic flow consisting of interacting Taylor vortices. We demonstrate that Lagrangian coherent structures (LCS), as identified by ridges in finite time Lyapunov exponents, are directly responsible for this coalescence of reactive scalar filaments. When highly concentrated filaments coalesce, reaction rates can be orders of magnitude greater than would be predicted in a well-mixed system. This is further supported by an idealized, analytical model that was developed to quantify the competing effects of scalar dilution and coalescence. Chaotic flows, known for their ability to efficiently dilute scalars, therefore have the competing effect of organizing initially distant scalars along the LCS at timescales shorter than that required for dilution, resulting in reaction enhancement.

  15. Scalar Decomposition of the Electromagnetic Vector Wave Equation

    NASA Astrophysics Data System (ADS)

    Franke, Carlos Rodolfo

    The accepted definition of separability of the electromagnetic vector wave equation requires that only one scalar field component exists in a scalar partial differential equation of no higher order than the second, for at least one of the scalar field components. The second order constraint so tightly restricts the mathematics that only the rectangular, the three cylindrical, and the spherical and conical coordinates can be separated. The constraint also permits separation of one scalar field component in prolate and oblate spheroidal coordinates, and paraboloidal coordinates, in that absence of azimuthal variations. The definition of separability makes it a particular attribute of a particular coordinate in a particular coordinate system, and not a general property of the coordinate system as a whole. The second order constraint on the scalar partial differential equation is now lifted, permitting the vector wave equation in any orthogonal curvilinear coordinate system to be completely separated into three scalar partial differential equations. The treatment is carried out for the circular-cylindrical and spherical coordinates, and the analysis indicates that the highest order of at least one of the uncoupled scalar partial differential equations in a given orthogonal curvilinear coordinate system is equal to twice the number of curvilinear coordinates.

  16. Generalized cosmic Chaplygin gas inspired intermediate standard scalar field inflation

    NASA Astrophysics Data System (ADS)

    Jawad, Abdul; Rani, Shamaila; Mohsaneen, Sidra

    2016-08-01

    We study the warm intermediate inflationary regime in the presence of generalized cosmic Chaplygin gas and an inflaton decay rate proportional to the temperature. For this purpose, we consider standard scalar field model during weak and strong dissipative regimes. We explore inflationary parameters like spectral index, scalar and tensor power spectra, tensor to scalar ratio and decay rate in order to compare the present model with recent observational data. The physical behavior of inflationary parameters is presented and found that all the results are agreed with recent observational data such as WMAP7, WMAP9 and Planck 2015.

  17. Scalar fluctuations in turbulent combustion - An experimental study

    NASA Astrophysics Data System (ADS)

    Ballal, D. R.; Chen, T. H.; Yaney, P. P.

    1986-01-01

    Temperature and velocity fluctuations data were gathered for turbulent premixed combustion to evaluate a model for scalar transport and scalar dissipation. The data were collected using laser Raman spectroscopy and laser Doppler anemometry with a premixed CH4-air flame from a Bunsen burner. Mean temperature profiles were generated and the pdf's temperature fluctuations were calculated. A wrinkled laminar flame structure was noted in the reaction zone, where the scalar field was anisotropic and where the temperature fluctuations exhibited peak values. The Bray, Moss and Libby model (1985) was successful in predicting the temperature fluctuation intensity and the dissipation ratios, the latter reaching peak values in the flame tip region.

  18. Cosmological models in Weyl geometrical scalar-tensor theory

    NASA Astrophysics Data System (ADS)

    Pucheu, M. L.; Alves Junior, F. A. P.; Barreto, A. B.; Romero, C.

    2016-09-01

    We investigate cosmological models in a recently proposed geometrical theory of gravity, in which the scalar field appears as part of the spacetime geometry. We extend the previous theory to include a scalar potential in the action. We solve the vacuum field equations for different choices of the scalar potential and give a detailed analysis of the solutions. We show that, in some cases, a cosmological scenario is found that seems to suggest the appearance of a geometric phase transition. We build a toy model, in which the accelerated expansion of the early Universe is driven by pure geometry.

  19. Black Hole Hair in Generalized Scalar-Tensor Gravity

    NASA Astrophysics Data System (ADS)

    Sotiriou, Thomas P.; Zhou, Shuang-Yong

    2014-06-01

    The most general action for a scalar field coupled to gravity that leads to second-order field equations for both the metric and the scalar—Horndeski's theory—is considered, with the extra assumption that the scalar satisfies shift symmetry. We show that in such theories, the scalar field is forced to have a nontrivial configuration in black hole spacetimes, unless one carefully tunes away a linear coupling with the Gauss-Bonnet invariant. Hence, black holes for generic theories in this class will have hair. This contradicts a recent no-hair theorem which seems to have overlooked the presence of this coupling.

  20. Scalar perturbation in symmetric Lee-Wick bouncing universe

    SciTech Connect

    Cho, Inyong; Kwon, O-Kab E-mail: okab@skku.edu

    2011-11-01

    We investigate the scalar perturbation in the Lee-Wick bouncing universe driven by an ordinary scalar field plus a ghost field. We consider only a symmetric evolution of the universe and the scalar fields about the bouncing point. The gauge invariant Sasaki-Mukhanov variable is numerically solved in the spatially flat gauge. We find a new form of the initial perturbation growing during the contracting phase. After the bouncing, this growing mode stabilizes to a constant mode which is responsible for the late-time power spectrum.

  1. Scalar perturbations in conformal rolling scenario with intermediate stage

    SciTech Connect

    Libanov, M.; Ramazanov, S.; Rubakov, V. E-mail: sabir@ms2.inr.ac.ru

    2011-06-01

    Scalar cosmological perturbations with nearly flat power spectrum may originate from perturbations of the phase of a scalar field conformally coupled to gravity and rolling down negative quartic potential. We consider a version of this scenario whose specific property is a long intermediate stage between the end of conformal rolling and horizon exit of the phase perturbations. Such a stage is natural, e.g., in cosmologies with ekpyrosis or genesis. Its existence results in small negative scalar tilt, statistical anisotropy of all even multipoles starting from quardupole of general structure (in contrast to the usually discussed single quadrupole of special type) and non-Gaussianity of a peculiar form.

  2. Charged scalar perturbations around Garfinkle-Horowitz-Strominger black holes

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng-Yong; Zhang, Shao-Jun; Wang, Bin

    2015-10-01

    We examine the stability of the Garfinkle-Horowitz-Strominger (GHS) black hole under charged scalar perturbations. Employing the appropriate numerical methods, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the results obtained in the de Sitter and anti-de Sitter black holes. Furthermore, we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.

  3. Noninertial effects on the quantum dynamics of scalar bosons

    NASA Astrophysics Data System (ADS)

    Castro, Luis B.

    2016-02-01

    The noninertial effect of rotating frames on the quantum dynamics of scalar bosons embedded in the background of a cosmic string is considered. In this work, scalar bosons are described by the Duffin-Kemmer-Petiau (DKP) formalism. Considering the DKP oscillator in this background the combined effects of a rotating frames and cosmic string on the equation of motion, energy spectrum, and DKP spinor are analyzed and discussed in detail. Additionally, the effect of rotating frames on the scalar bosons' localization is studied.

  4. Scalar dark matter in an extra dimension inspired model

    NASA Astrophysics Data System (ADS)

    Lineros, Roberto; Pereira dos Santos, Fabio

    2016-05-01

    In this work we consider a singlet scalar propagating in a flat large extra dimension. The first Kaluza-Klein mode associated to this singlet scalar will be a viable dark matter candidate. The tower of new particles enriches the calculation of the relic density due effect of coannihilation. For large mass splitting, the model converges to the predictions of the singlet dark matter model. For nearly degenerate mass spectrum, coannihilations increase the cross-sections used for direct and indirect dark matter searches. We investigate the impact of the Kaluza-Klein tower associated to singlet scalar for indirect and direct detection of dark matter.

  5. Gaugino and scalar masses in the landscape

    NASA Astrophysics Data System (ADS)

    Conlon, Joseph P.; Quevedo, Fernando

    2006-06-01

    In this letter we demonstrate the genericity of suppressed gaugino masses Ma ~ m3/2/ln (MPlanck/m3/2) in the IIB string landscape, by showing that this relation holds for D7-brane gauginos whenever the associated modulus is stabilised by nonperturbative effects. Although m3/2 and Ma take many different values across the landscape, the above small mass hierarchy is maintained. We show that it is valid for models with an arbitrary number of moduli and applies to both the KKLT and exponentially large volume approaches to Kähler moduli stabilisation. In the latter case we explicitly calculate gaugino and moduli masses for compactifications on the two-modulus Calabi-Yau Bbb P4[1,1,1,6,9]. In the large-volume scenario we also show that soft scalar masses are approximately universal with mi2 ~ m3/22(1+epsiloni), with the non-universality parametrised by epsiloni ~ 1/ln (MP/m3/2)2 ~ (1/1000). We briefly discuss possible phenomenological implications of our results.

  6. Transverse relaxation of scalar-coupled protons.

    PubMed

    Segawa, Takuya F; Baishya, Bikash; Bodenhausen, Geoffrey

    2010-10-25

    In a preliminary communication (B. Baishya, T. F. Segawa, G. Bodenhausen, J. Am. Chem. Soc. 2009, 131, 17538-17539), we recently demonstrated that it is possible to obtain clean echo decays of protons in biomolecules despite the presence of homonuclear scalar couplings. These unmodulated decays allow one to determine apparent transverse relaxation rates R(2) (app) of individual protons. Herein, we report the observation of R(2) (app) for three methyl protons, four amide H(N) protons, and all 11 backbone H(α) protons in cyclosporin A. If the proton resonances overlap, their R(2) (app) rates can be measured by transferring their magnetization to neighboring (13)C nuclei, which are less prone to overlap. The R(2) (app) rates of protons attached to (13)C are faster than those attached to (12)C because of (13)C-(1)H dipolar interactions. The differences of these rates allow the determination of local correlation functions. Backbone H(N) and H(α) protons that have fast decay rates R(2) (app) also feature fast longitudinal relaxation rates R(1) and intense NOESY cross peaks that are typical of crowded environments. Variations of R(2) (app) rates of backbone H(α) protons in similar amino acids reflect differences in local environments.

  7. Scalar Green function of the Kerr spacetime

    NASA Astrophysics Data System (ADS)

    Yang, Huan; Zhang, Fan; Zimmerman, Aaron; Chen, Yanbei

    2014-03-01

    In this paper we study the scalar Green function in the Kerr spacetime using Wentzel-Kramers-Brillouin (WKB) methods. The Green function can be expressed by Fourier-transforming to its frequency-domain counterpart, and with the help of complex analysis it can be divided into parts: 1) the "direct part," which propagates on the light cone and dominates at very early times; 2) the "quasinormal-mode part," which represents the waves traveling around the photon sphere and is important at early and intermediate times; and 3) the "tail part," which is due to scattering by the Coulomb-type potential and becomes more important at later times. We focus on the "quasinormal-mode part" of the Green function and derive an approximate analytical formula for it using WKB techniques. This approximate Green function diverges at points that are connected by null geodesics, and it recovers the fourfold singular structure of Green functions that are seen in Schwarzschild and other spacetimes. It also carries unique signatures of the Kerr spacetime such as frame dragging. Along the way, we also derive approximate quasinormal-mode wave functions and expressions for the black hole excitation factors in the Kerr spacetime. We expect this work to benefit the understanding of both wave propagation and the problem of self-force in the Kerr spacetime.

  8. DBI scalar field theory for QGP hydrodynamics

    NASA Astrophysics Data System (ADS)

    Nastase, Horatiu

    2016-07-01

    A way to describe the hydrodynamics of the quark-gluon plasma using a Dirac-Born-Infeld (DBI) action is proposed, based on the model found by Heisenberg for high energy scattering of nucleons. The expanding plasma is described as a shockwave in a DBI model for a real scalar standing in for the pion, and I show that one obtains a fluid description in terms of a relativistic fluid that near the shock is approximately ideal (η ≃0 ) and conformal. One can introduce an extra term inside the square root of the DBI action that generates a shear viscosity term in the energy-momentum tensor near the shock, as well as a bulk viscosity, and regulates the behavior of the energy density at the shock, making it finite. The resulting fluid satisfies the relativistic Navier-Stokes equation with uμ,ρ ,P ,η defined in terms of ϕ and its derivatives. One finds a relation between the parameters of the theory and the quark-gluon plasma thermodynamics, α /β2=η /(s T ), and by fixing α and β from usual (low multiplicity) particle scattering, one finds T ∝mπ.

  9. A search for third generation scalar leptoquarks

    SciTech Connect

    Zatserklyaniy, Andriy

    2006-08-01

    Leptoquarks (LQ) are particles with both color and lepton number predicted in some gauge theories and composite models. Current theory suggests that leptoquarks would come in three different generations. We report on a search for charge 1/3 third generation leptoquarks produced in p$\\bar{p}$ collisions at √s = 1.96 TeV using data collected by the D0 detector at Fermilab. Such leptoquarks would decay into a tau-neutrino plus a b-quark with branching fraction B. We present preliminary results on an analysis where both leptoquarks decay into neutrinos giving a final state with missing energy and two b-jets. Using 425(recorded) pb-1 of data, we place limits on σ(p$\\bar{p}$ → LQ$\\bar{LQ}$)B2 as a function of the leptoquark mass. Assuming B = 1, we excluded at the 95% confidence level scalar third generation leptoquarks with MLQ < 219 GeV.

  10. RNA structure and scalar coupling constants

    SciTech Connect

    Tinoco, I. Jr.; Cai, Z.; Hines, J.V.; Landry, S.M.; SantaLucia, J. Jr.; Shen, L.X.; Varani, G.

    1994-12-01

    Signs and magnitudes of scalar coupling constants-spin-spin splittings-comprise a very large amount of data that can be used to establish the conformations of RNA molecules. Proton-proton and proton-phosphorus splittings have been used the most, but the availability of {sup 13}C-and {sup 15}N-labeled molecules allow many more coupling constants to be used for determining conformation. We will systematically consider the torsion angles that characterize a nucleotide unit and the coupling constants that depend on the values of these torsion angles. Karplus-type equations have been established relating many three-bond coupling constants to torsion angles. However, one- and two-bond coupling constants can also depend on conformation. Serianni and coworkers measured carbon-proton coupling constants in ribonucleosides and have calculated their values as a function of conformation. The signs of two-bond coupling can be very useful because it is easier to measure a sign than an accurate magnitude.

  11. Nonrelativistic approach for cosmological scalar field dark matter

    NASA Astrophysics Data System (ADS)

    Ureña-López, L. Arturo

    2014-07-01

    We derive nonrelativistic equations of motion for the formation of cosmological structure in a scalar field dark matter (SFDM) model corresponding to a complex scalar field endowed with a quadratic scalar potential. Starting with the equations of motion written in the Newtonian gauge of scalar perturbations, we separate out the involved fields into relativistic and nonrelativistic parts and find the equations of motion for the latter that can be used to build up the full solution. One important assumption will be that the SFDM field is in the regime of fast oscillations, under which its behavior in the homogeneous regime is exactly that of cold dark matter. The resultant equations are quite similar to the Schrödinger-Poisson system of Newtonian boson stars plus relativistic leftovers, and they can be used to study the formation of cosmological structure in SFDM models, and others alike, to ultimately prove their viability as complete dark matter models.

  12. Scalar mesons and the search for the 0{sup ++} Glueball

    SciTech Connect

    Ulrike Thoma

    2002-10-01

    The possibility that gluonic excitations of hadronic matter or of the QCD vacuum may exist is perhaps one of the most fascinating topics in hadron spectroscopy. Glueballs are predicted by many models; in particular present-day lattice gauge calculations require their existence. All these models agree that the lightest glueball should have scalar quantum numbers and a mass around 1.6 GeV, which corresponds to the mass region where the scalar qq[bar]-mesons are expected. Therefore mixing effects can complicate the search for the glueball. Experiments indeed show an overpopulation of states, for which many different interpretations exist. This reflects the complexity of the situation. New data from various experiments on scalar states give hints toward an interpretation of the scalar states. But, still many questions remain.

  13. Wormholes, the weak energy condition, and scalar-tensor gravity

    NASA Astrophysics Data System (ADS)

    Shaikh, Rajibul; Kar, Sayan

    2016-07-01

    We obtain a large class of Lorentzian wormhole spacetimes in scalar-tensor gravity, for which the matter stress energy does satisfy the weak energy condition. Our constructions have zero Ricci scalar and an everywhere finite, nonzero scalar field profile. Interpreting the scalar-tensor gravity as an effective on-brane theory resulting from a two-brane Randall-Sundrum model of warped extra dimensions, it is possible to link wormhole existence with that of extra dimensions. We study the geometry, matter content, gravitational redshift and circular orbits in such wormholes and argue that our examples are perhaps among those which may have some observational relevance in astrophysics in the future. We also study traversability and find that our wormholes are indeed traversable for values of the metric parameters satisfying the weak energy condition.

  14. Bianchi type-I models with conformally invariant scalar field

    SciTech Connect

    Accioly, A.J.; Vaidya, A.N.; Som, M.M.

    1983-05-15

    The solutions of the Einstein equations with the trace-free energy-momentum tensor of conformally invariant scalar field as source are obtained in a spatially homogeneous anisotropic space-time. Some interesting features of the solutions are discussed.

  15. Two scalar field cosmology: Conservation laws and exact solutions

    NASA Astrophysics Data System (ADS)

    Paliathanasis, Andronikos; Tsamparlis, Michael

    2014-08-01

    We consider the two scalar field cosmology in a Friedmann Robertson Walker spatially flat spacetime where the scalar fields interact both in the kinetic part and the potential. We apply the Noether point symmetries in order to define the interaction of the scalar fields. We use the point symmetries in order to write the field equations in the normal coordinates, and we find that the Lagrangian of the field equations which admits at least three Noether point symmetries describes linear Newtonian systems. Furthermore, by using the corresponding conservation laws we find exact solutions of the field equations. Finally, we generalize our results to the case of N scalar fields interacting both in their potential and their kinematic part in a flat Friedmann Robertson Walker background.

  16. Kasner solutions, climbing scalars and big-bang singularity

    SciTech Connect

    Condeescu, Cezar; Dudas, Emilian E-mail: emilian.dudas@cpht.polytechnique.fr

    2013-08-01

    We elaborate on a recently discovered phenomenon where a scalar field close to big-bang is forced to climb a steep potential by its dynamics. We analyze the phenomenon in more general terms by writing the leading order equations of motion near the singularity. We formulate the conditions for climbing to exist in the case of several scalars and after inclusion of higher-derivative corrections and we apply our results to some models of moduli stabilization. We analyze an example with steep stabilizing potential and notice again a related critical behavior: for a potential steepness above a critical value, going backwards towards big-bang, the scalar undergoes wilder oscillations, with the steep potential pushing it back at every passage and not allowing the scalar to escape to infinity. Whereas it was pointed out earlier that there are possible implications of the climbing phase to CMB, we point out here another potential application, to the issue of initial conditions in inflation.

  17. Modeling scalar flux and the energy and dissipation equations

    NASA Technical Reports Server (NTRS)

    Yoshizawa, A.

    1987-01-01

    Closure models derived from the Two-Scale Direct-Interaction Approximation were compared with data from direct simulations of turbulence. Attention was restricted to anisotropic scalar diffusion models, models for the energy dissipation equation, and models for energy diffusion.

  18. Search for scalar glueballs from heavy meson decays

    SciTech Connect

    Lue Caidian; Shen Yuelong; Wang Wei

    2010-08-05

    We investigate the transition form factors of B meson decays into a scalar glueball in the light-cone formalism. Compared with form factors of B to ordinary scalar mesons, the B-to-glueball form factors have the same power in the expansion of 1/m{sub B}. Taking into account the leading twist light-cone distribution amplitude, we find that they are numerically smaller than those form factors of B to ordinary scalar mesons. In the presence of mixing between glueballs and ordinary scalar mesons, the possibility to extract the mixing parameters from semileptonic B decays and nonleptonic B decays are explored. We also point out a clean way to identify a glueball through B{sub c} decays.

  19. Relating spectral indices to tensor and scalar amplitudes in inflation

    SciTech Connect

    Kolb, Edward W.; Vadas, Sharon L.

    1994-02-01

    Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections'' to previously derived formulae can dominate if the tensor to scalar ratio is small. For instance, if VV"/(V')2≠1 or if [mPI2/(4π)]||V'"/V'|| ≳ 1, where V(Φ) is the inflaton potential and mPlis the Planck mass, then the previously used simple relations between the indices and the tensor to scalar ratio fails. This failure occurs in particular for natural inflation, Coleman--Weinberg inflation, and ``chaotic'' inflation.

  20. General analytic solutions of scalar field cosmology with arbitrary potential

    NASA Astrophysics Data System (ADS)

    Dimakis, N.; Karagiorgos, A.; Zampeli, Adamantia; Paliathanasis, Andronikos; Christodoulakis, T.; Terzis, Petros A.

    2016-06-01

    We present the solution space for the case of a minimally coupled scalar field with arbitrary potential in a Friedmann-Lemaître-Robertson-Walker metric. This is made possible due to the existence of a nonlocal integral of motion corresponding to the conformal Killing field of the two-dimensional minisuperspace metric. Both the spatially flat and nonflat cases are studied first in the presence of only the scalar field and subsequently with the addition of noninteracting perfect fluids. It is verified that this addition does not change the general form of the solution, but only the particular expressions of the scalar field and the potential. The results are applied in the case of parametric dark energy models where we derive the scalar field equivalence solution for some proposed models in the literature.

  1. Quantum reduced loop gravity: Extension to scalar fields

    NASA Astrophysics Data System (ADS)

    Bilski, Jakub; Alesci, Emanuele; Cianfrani, Francesco

    2015-12-01

    The quantization of the Hamiltonian for a scalar field is performed in the framework of quantum reduced loop gravity. We outline how the regularization can be performed by using the analogous tools adopted in full loop quantum gravity, and the matrix elements of the resulting operator between basis states are analytic coefficients. These achievements open the way for a consistent analysis of the quantum gravity corrections to the classical dynamics of gravity in the presence of a scalar field in a cosmological setting.

  2. Renormalizable Electrodynamics of Scalar and Vector Mesons. Part II

    DOE R&D Accomplishments Database

    Salam, Abdus; Delbourgo, Robert

    1964-01-01

    The "gauge" technique" for solving theories introduced in an earlier paper is applied to scalar and vector electrodynamics. It is shown that for scalar electrodynamics, there is no {lambda}φ*2φ2 infinity in the theory, while with conventional subtractions vector electrodynamics is completely finite. The essential ideas of the gauge technique are explained in section 3, and a preliminary set of rules for finite computation in vector electrodynamics is set out in Eqs. (7.28) - (7.34).

  3. Wormhole-induced operators for a massless scalar field

    SciTech Connect

    Goto, T.; Okada, Y. )

    1991-05-15

    Bilocal operators induced by an axionic wormhole solution are obtained in the case of a massless scalar field. For this purpose, we first show that the calculation of a Green's function for the scalar field on the wormhole background is reduced to a one-dimensional potential-barrier problem. We then evaluate numerically the asymptotic behavior of the Green's function and identify the effective interaction induced by the wormhole.

  4. Relating neutrino masses to dilepton modes of doubly charged scalars

    SciTech Connect

    Chen, Chian-Shu; Geng, C. Q.

    2010-11-15

    We study a model with Majorana neutrino masses generated through doubly charged scalars at two-loop level. We give explicit relationships between the neutrino masses and the same sign dilepton decays of the doubly charged scalars. In particular, we demonstrate that in the tribimaximal limit of the neutrino mixings, the absolute neutrino masses and Majorana phases can be extracted through the measurements of the dilepton modes at colliders.

  5. FAST TRACK COMMUNICATION: Lorentzian manifolds and scalar curvature invariants

    NASA Astrophysics Data System (ADS)

    Coley, Alan; Hervik, Sigbjørn; Pelavas, Nicos

    2010-05-01

    We discuss (arbitrary-dimensional) Lorentzian manifolds and the scalar polynomial curvature invariants constructed from the Riemann tensor and its covariant derivatives. Recently, we have shown that in four dimensions a Lorentzian spacetime metric is either \\mathcal {I}-non-degenerate, and hence locally characterized by its scalar polynomial curvature invariants, or is a degenerate Kundt spacetime. We present a number of results that generalize these results to higher dimensions and discuss their consequences and potential physical applications.

  6. A unified optical theorem for scalar and vectorial wave fields.

    PubMed

    Wapenaar, Kees; Douma, Huub

    2012-05-01

    The generalized optical theorem is an integral relation for the angle-dependent scattering amplitude of an inhomogeneous scattering object embedded in a homogeneous background. It has been derived separately for several scalar and vectorial wave phenomena. Here a unified optical theorem is derived that encompasses the separate versions for scalar and vectorial waves. Moreover, this unified theorem also holds for scattering by anisotropic elastic and piezoelectric scatterers as well as bianisotropic (non-reciprocal) EM scatterers. PMID:22559339

  7. Search for scalar top and bottom quarks at the Tevatron

    SciTech Connect

    Calfayan, Philippe; /Munich U.

    2009-01-01

    This document reviews recent results on the search for scalar top and scalar bottom quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The analyses presented are based on data samples with integrated luminosities from 1.0 to 1.9 fb{sup -1} recorded at the Tevatron with the D0 and CDF detectors.

  8. Unimodular metagravity vs. general relativity with a scalar field

    SciTech Connect

    Pirogov, Yu. F.

    2010-01-15

    The unimodular metagravity, with the graviscalar as a dark matter, is compared with General Relativity (GR) in the presence of a scalar field. The effect of the graviscalar on the static spherically symmetric metric is studied. An exact limit solution representing a new cosmic object, the (harmonic) graviscalar black hole, is given. The relation with the black hole in the environment of a scalar field in GR is discussed.

  9. A unified optical theorem for scalar and vectorial wave fields.

    PubMed

    Wapenaar, Kees; Douma, Huub

    2012-05-01

    The generalized optical theorem is an integral relation for the angle-dependent scattering amplitude of an inhomogeneous scattering object embedded in a homogeneous background. It has been derived separately for several scalar and vectorial wave phenomena. Here a unified optical theorem is derived that encompasses the separate versions for scalar and vectorial waves. Moreover, this unified theorem also holds for scattering by anisotropic elastic and piezoelectric scatterers as well as bianisotropic (non-reciprocal) EM scatterers.

  10. Perfect focusing of scalar wave fields in three dimensions.

    PubMed

    Benítez, Pablo; Miñano, Juan C; González, Juan C

    2010-04-12

    A method to design isotropic inhomogeneous refractive index distribution is presented, in which the scalar wave field solutions propagate exactly on an eikonal function (i.e., remaining constant on the Geometrical Optics wavefronts). This method is applied to the design of "dipole lenses", which perfectly focus a scalar wave field emitted from a point source onto a point absorber, in both two and three dimensions. Also, the Maxwell fish-eye lens in two and three dimensions is analysed.

  11. Decay of massive scalar hair on brane black holes

    SciTech Connect

    Rogatko, Marek; Szyplowska, Agnieszka

    2007-08-15

    We study analytically the intermediate and late-time behavior of the massive scalar field in the background of static spherically symmetric brane black hole solutions. The intermediate asymptotic behavior of the scalar field reveals the dependence on the field's parameter mass as well as the multipole moment l, while the late-time behavior has the power-law decay rate independent of those factors.

  12. Inflation from cosmological constant and nonminimally coupled scalar

    NASA Astrophysics Data System (ADS)

    Glavan, Dražen; Marunović, Anja; Prokopec, Tomislav

    2015-08-01

    We consider inflation in a universe with a positive cosmological constant and a nonminimally coupled scalar field, in which the field couples both quadratically and quartically to the Ricci scalar. When considered in the Einstein frame and when the nonminimal couplings are negative, the field starts in slow roll and inflation ends with an asymptotic value of the principal slow-roll parameter, ɛE=4 /3 . Graceful exit can be achieved by suitably (tightly) coupling the scalar field to matter, such that at late time the total energy density reaches the scaling of matter, ɛE=ɛm . Quite generically the model produces a red spectrum of scalar cosmological perturbations and a small amount of gravitational radiation. With a suitable choice of the nonminimal couplings, the spectral slope can be as large as ns≃0.955 , which is about one standard deviation away from the central value measured by the Planck satellite. The model can be ruled out by future measurements if any of the following is observed: (a) the spectral index of scalar perturbations is ns>0.960 ; (b) the amplitude of tensor perturbations is above about r ˜10-2 ; (c) the running of the spectral index of scalar perturbations is positive.

  13. Scalar geometry and masses in Calabi-Yau string models

    NASA Astrophysics Data System (ADS)

    Farquet, Daniel; Scrucca, Claudio A.

    2012-09-01

    We study the geometry of the scalar manifolds emerging in the no-scale sector of Kähler moduli and matter fields in generic Calabi-Yau string compactifications, and describe its implications on scalar masses. We consider both heterotic and orientifold models and compare their characteristics. We start from a general formula for the Kähler potential as a function of the topological compactification data and study the structure of the curvature tensor. We then determine the conditions for the space to be symmetric and show that whenever this is the case the heterotic and the orientifold models give the same scalar manifold. We finally study the structure of scalar masses in this type of geometries, assuming that a generic superpotential triggers spontaneous supersymmetry breaking. We show in particular that their behavior crucially depends on the parameters controlling the departure of the geometry from the coset situation. We first investigate the average sGoldstino mass in the hidden sector and its sign, and study the implications on vacuum metastability and the mass of the lightest scalar. We next examine the soft scalar masses in the visible sector and their flavor structure, and study the possibility of realizing a mild form of sequestering relying on a global symmetry.

  14. Fermion damping in a fermion-scalar plasma

    SciTech Connect

    Boyanovsky, D.; Wang, S.; de Vega, H.J.; Lee, D.; Ng, Y.J.

    1999-05-01

    In this article we study the dynamics of fermions in a fermion-scalar plasma. We begin by obtaining the effective in-medium Dirac equation in real time which is fully renormalized and causal and leads to the initial value problem. For a heavy scalar we find the novel result that the {ital decay} of the scalar into fermion pairs in the medium leads to damping of the fermionic excitations and their in-medium propagation as quasiparticles. That is, the fermions acquire a width due to the decay of the heavier scalar in the medium. We find the damping rate to lowest order in the Yukawa coupling for arbitrary values of scalar and fermion masses, temperature and fermion momentum. An all-order expression for the damping rate in terms of the exact quasiparticle wave functions is established. A kinetic Boltzmann approach to the relaxation of the fermionic distribution function confirms the damping of fermionic excitations as a consequence of the induced decay of heavy scalars in the medium. A linearization of the Boltzmann equation near equilibrium clearly displays the relationship between the damping rate of fermionic mean fields and the fermion interaction rate to lowest order in the Yukawa coupling directly in real time. {copyright} {ital 1999} {ital The American Physical Society}

  15. New Isolated-Pentagon-Rule and Skeletally Transformed Isomers of C100 Fullerene Identified by Structure Elucidation of their Chloro Derivatives.

    PubMed

    Wang, Song; Yang, Shangfeng; Kemnitz, Erhard; Troyanov, Sergey I

    2016-03-01

    High-temperature chlorination of C100 fullerene followed by X-ray structure determination of the chloro derivatives enabled the identification of three isomers of C100 from the fullerene soot, specifically numbers 18, 425, and 417, which obey the isolated pentagon rule (IPR). Among them, isomers C1-C100 (425) and C2-C100 (18) afforded C1-C100 (425)Cl22 and C2-C100 (18)Cl28/30 compounds, respectively, which retain their IPR cage connectivities. In contrast, isomer C2v -C100 (417) gives Cs -C100 (417)Cl28 which undergoes a skeletal transformation by the loss of a C2  fragment, resulting in the formation of a nonclassical (NC) C1-C98 (NC)Cl26 with a heptagon in the carbon cage. Most probably, two nonclassical C1-C100 (NC)Cl18/22 chloro derivatives originate from the IPR isomer C1-C100 (382), although both C1-C100 (344) and even nonclassical C1-C100 (NC) can be also considered as the starting isomers. PMID:26848074

  16. New approach to one-loop calculations in gauge theories

    SciTech Connect

    Bern, Z.; Kosower, D.A.

    1988-09-15

    We propose using the technology of four-dimensional string theories to calculate amplitudes in gauge theories. Strings make such calculations much more efficient by summing a large number of Feynman diagrams all at once. We check the idea by constructing a string model reducing to a pure non-Abelian gauge theory in the infinite-tension limit and computing its ..beta.. function with these techniques.

  17. One-loop chiral perturbation theory with two fermion representations

    NASA Astrophysics Data System (ADS)

    DeGrand, Thomas; Golterman, Maarten; Neil, Ethan T.; Shamir, Yigal

    2016-07-01

    We develop chiral perturbation theory for chirally broken theories with fermions in two different representations of the gauge group. Any such theory has a nonanomalous singlet U (1 )A symmetry, yielding an additional Nambu-Goldstone boson when spontaneously broken. We calculate the next-to-leading order corrections for the pseudoscalar masses and decay constants, which include the singlet Nambu-Goldstone boson, as well as for the two condensates. The results can be generalized to more than two representations.

  18. Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons

    SciTech Connect

    Cheng Haiyang; Chua Chunkhiang; Yang Kweichou

    2006-01-01

    The hadronic charmless B decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. Although the light scalar mesons f{sub 0}(980) and a{sub 0}(980) are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. The short-distance approach suffices to explain the observed large rates of f{sub 0}(980)K{sup -} and f{sub 0}(980)K{sup 0} that receive major penguin contributions from the b{yields}sss process. When f{sub 0}(980) is assigned as a four-quark bound state, there exist extra diagrams contributing to B{yields}f{sub 0}(980)K. Therefore, a priori the f{sub 0}(980)K rate is not necessarily suppressed for a four-quark state f{sub 0}(980). The predicted B{sup 0}{yields}a{sub 0}{sup {+-}}(980){pi}{sup {+-}} and a{sub 0}{sup +}(980)K{sup -} rates exceed the current experimental limits, favoring a four-quark nature for a{sub 0}(980). The penguin-dominated modes a{sub 0}(980)K and a{sub 0}(1450)K receive predominant weak annihilation contributions. There exists a twofold experimental ambiguity in extracting the branching ratio of B{sup -}{yields}K{sub 0}*{sup 0}(1430){pi}{sup -}, which can be resolved by measuring other K{sub 0}*(1430){pi} modes in conjunction with the isospin symmetry consideration. Large weak annihilation contributions are needed to explain the K{sub 0}*(1430){pi} data. The decay B{sup 0}{yields}{kappa}{sup +}K{sup -} provides a nice ground for testing the 4-quark and 2-quark nature of the {kappa} meson. It can proceed through W-exchange and hence is quite suppressed if {kappa} is made of two quarks, while it receives a tree contribution if {kappa} is predominately a four

  19. Scalar-field coordinates and the spherically symmetric Einstein equations for a zero-mass scalar field

    NASA Astrophysics Data System (ADS)

    Berberian, John Edwin

    1999-01-01

    A new framework is presented for analysing the spherically symmetric Einstein field equations for a zero-mass scalar field. The framework consists of a coordinate system (p, q), where the coordinate p is the scalar field, and q is a coordinate chosen to be orthogonal to p. This idea allows for a reduction of the field equations into a system of two first order partial differential equations for the areal metric function gqq and a mass function m . The metric coefficients in this coordinate system then take on values which are simply related to the scalars of the problem: 1->f˙1 ->f,gq q and-via the field equations-the scalar curvature R as well. The scalar field coordinate system is shown to have many advantages. Many of the known exact solutions (e.g. static, Roberts) are represented simply, and new self- similar solutions are derived. The framework is then applied to the problem of matching spherically symmetric scalar-tensor vacuum solutions to a homogeneous and isotropic dust solution (e.g. scalar- tensor Einstein-Straus swiss cheese solutions, scalar- tensor Oppenheimer-Snyder dust ball collapse). Scalar field coordinates are shown to be ideal for such an application. We derive the necessary matching conditions in scalar field coordinates, and show how they imply a natural extension of the Schücking condition for spherically symmetric vacuum in general relativity. The problem of finding a vacuum solution which matches a given homogeneous and isotropic solution is examined. It is found that the matching conditions are sufficient to guarantee local existence and uniqueness of the vacuum solution if it is assumed that the scalar field has neither maxima nor minima on the matching interface. In order to find explicit matched solutions, criteria are developed to screen known exact vacuum solutions for matchability, and procedures are given for determining the details of the homogeneous and isotropic solution (curvature constant, comoving radial coordinate of the

  20. N-body simulations for coupled scalar-field cosmology

    SciTech Connect

    Li Baojiu; Barrow, John D.

    2011-01-15

    We describe in detail the general methodology and numerical implementation of consistent N-body simulations for coupled-scalar-field models, including background cosmology and the generation of initial conditions (with the different couplings to different matter species taken into account). We perform fully consistent simulations for a class of coupled-scalar-field models with an inverse power-law potential and negative coupling constant, for which the chameleon mechanism does not work. We find that in such cosmological models the scalar-field potential plays a negligible role except in the background expansion, and the fifth force that is produced is proportional to gravity in magnitude, justifying the use of a rescaled gravitational constant G in some earlier N-body simulation works for similar models. We then study the effects of the scalar coupling on the nonlinear matter power spectra and compare with linear perturbation calculations to see the agreement and places where the nonlinear treatment deviates from the linear approximation. We also propose an algorithm to identify gravitationally virialized matter halos, trying to take account of the fact that the virialization itself is also modified by the scalar-field coupling. We use the algorithm to measure the mass function and study the properties of dark-matter halos. We find that the net effect of the scalar coupling helps produce more heavy halos in our simulation boxes and suppresses the inner (but not the outer) density profile of halos compared with the {Lambda}CDM prediction, while the suppression weakens as the coupling between the scalar field and dark-matter particles increases in strength.

  1. Quasistationary solutions of scalar fields around accreting black holes

    NASA Astrophysics Data System (ADS)

    Sanchis-Gual, Nicolas; Degollado, Juan Carlos; Izquierdo, Paula; Font, José A.; Montero, Pedro J.

    2016-08-01

    Massive scalar fields can form long-lived configurations around black holes. These configurations, dubbed quasibound states, have been studied both in the linear and nonlinear regimes. In this paper, we show that quasibound states can form in a dynamical scenario in which the mass of the black hole grows significantly due to the capture of infalling matter. We solve the Klein-Gordon equation numerically in spherical symmetry, mimicking the evolution of the spacetime through a sequence of analytic Schwarzschild black hole solutions of increasing mass. It is found that the frequency of oscillation of the quasibound states decreases as the mass of the black hole increases. In addition, accretion leads to an increase of the exponential decay of the scalar field energy. We compare the black hole mass growth rates used in our study with estimates from observational surveys and extrapolate our results to values of the scalar field masses consistent with models that propose scalar fields as dark matter in the universe. We show that, even for unrealistically large mass accretion rates, quasibound states around accreting black holes can survive for cosmological time scales. Our results provide further support to the intriguing possibility of the existence of dark matter halos based on (ultralight) scalar fields surrounding supermassive black holes in galactic centers.

  2. New scalar constraint operator for loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Assanioussi, Mehdi; Lewandowski, Jerzy; Mäkinen, Ilkka

    2015-08-01

    We present a concrete and explicit construction of a new scalar constraint operator for loop quantum gravity. The operator is defined on the recently introduced space of partially diffeomorphism invariant states, and this space is preserved by the action of the operator. To define the Euclidean part of the scalar constraint operator, we propose a specific regularization based on the idea of so-called "special" loops. The Lorentzian part of the quantum scalar constraint is merely the curvature operator that has been introduced in an earlier work. Due to the properties of the special loops assignment, the adjoint operator of the nonsymmetric constraint operator is densely defined on the partially diffeomorphism invariant Hilbert space. This fact opens up the possibility of defining a symmetric scalar constraint operator as a suitable combination of the original operator and its adjoint. We also show that the algebra of the scalar constraint operators is anomaly free, and describe the structure of the kernel of these operators on a general level.

  3. Long-lived, colour-triplet scalars from unnaturalness

    DOE PAGES

    Barnard, James; Cox, Peter; Gherghetta, Tony; Spray, Andrew

    2016-03-01

    We study that long-lived, colour-triplet scalars are a generic prediction of unnatural, or split, composite Higgs models where the spontaneous global-symmetry breaking scale f ≳ 10TeV and an unbroken SU(5) symmetry is preserved. Since the triplet scalars are pseudo Nambu- Goldstone bosons they are split from the much heavier composite-sector resonances and are the lightest exotic, coloured states. This makes them ideal to search for at colliders. Due to discrete symmetries the triplet scalar decays via a dimension-six term and given the large suppression scale f is often metastable. We show that existing searches for collider-stable R-hadrons from Run-I atmore » the LHC forbid a triplet scalar mass below 845 GeV, whereas with 300 fb-1 at 13TeV triplet scalar masses up to 1.4TeV can be discovered. For shorter lifetimes displaced-vertex searches provide a discovery reach of up to 1.8TeV. Also, we present exclusion and discovery reaches of future hadron colliders as well as indirect limits that arise from modi cations of the Higgs couplings.« less

  4. Late time solution for interacting scalar in accelerating spaces

    SciTech Connect

    Prokopec, Tomislav

    2015-11-01

    We consider stochastic inflation in an interacting scalar field in spatially homogeneous accelerating space-times with a constant principal slow roll parameter ε. We show that, if the scalar potential is scale invariant (which is the case when scalar contains quartic self-interaction and couples non-minimally to gravity), the late-time solution on accelerating FLRW spaces can be described by a probability distribution function (PDF) ρ which is a function of φ/H only, where φ=φ( x-vector ) is the scalar field and H=H(t) denotes the Hubble parameter. We give explicit late-time solutions for ρarrow ρ{sub ∞}(φ/H), and thereby find the order ε corrections to the Starobinsky-Yokoyama result. This PDF can then be used to calculate e.g. various n-point functions of the (self-interacting) scalar field, which are valid at late times in arbitrary accelerating space-times with ε= constant.

  5. Modified scalar and tensor spectra in spinor driven inflation

    SciTech Connect

    Gredat, Damien; Shankaranarayanan, S. E-mail: shanki@iisertvm.ac.in

    2010-01-01

    One of the firm predictions of single-scalar field inflationary cosmology is the consistency relation between scalar and tensor perturbations. It has been argued that such a relation, if observationally verified, would offer strong support for the idea of inflation. In this letter, we critically analyze the validity of the consistency relation in the context of spinor driven inflation. The spinflaton – a condensate of the Elko field — has a single scalar degree of freedom and leads to the same acceleration equation as the inflaton. We obtain the perturbation equations for the Einstein-Elko system and show that the scalar perturbations are purely adiabatic and the sound speed of the perturbations is identically one. We obtain the generalized Mukhanov-Sasaki equation for the spinor driven inflation and show that, in the slow-roll limit, the scalar and tensor spectra are nearly scale-invariant. We also show that spinor driven inflation naturally predicts running of spectral indices and the consistency relations for the spectra are modified.

  6. Effect of dilatation on scalar dissipation in turbulent premixed flames

    SciTech Connect

    Swaminathan, N.; Bray, K.N.C.

    2005-12-01

    The scalar dissipation rate signifies the local mixing rate and thus plays a vital role in the modeling of reaction rate in turbulent flames. The local mixing rate is influenced by the turbulence, the chemical, and the molecular diffusion processes which are strongly coupled in turbulent premixed flames. Thus, a model for the mean scalar dissipation rate, and hence the mean reaction rate, should include the contributions of these processes. Earlier models for the scalar dissipation rate include only a turbulence time scale. In this study, we derive exact transport equations for the instantaneous and the mean scalar dissipation rates. Using these equations, a simple algebraic model for the mean scalar dissipation rate is obtained. This model includes a chemical as well as a turbulence time scale and its prediction compares well with direct numerical simulation results. Reynolds-averaged Navier-Stokes calculations of a test flame using the model obtained here show that the contribution of dilatation to local turbulent mixing rate is important to predict the propagation phenomenon.

  7. Survival of scalar zero modes in warped extra dimensions

    SciTech Connect

    George, Damien P.

    2011-05-15

    Models with an extra dimension generally contain background scalar fields in a nontrivial configuration, whose stability must be ensured. With gravity present, the extra dimension is warped by the scalars, and the spin-0 degrees of freedom in the metric mix with the scalar perturbations. Where possible, we formally solve the coupled Schroedinger equations for the zero modes of these spin-0 perturbations. When specializing to the case of two scalars with a potential generated by a superpotential, we are able to fully solve the system. We show how these zero modes can be used to construct a solution matrix, whose eigenvalues tell whether a normalizable zero mode exists, and how many negative mass modes exist. These facts are crucial in determining stability of the corresponding background configuration. We provide examples of the general analysis for domain-wall models of an infinite extra dimension and domain-wall soft-wall models. For five-dimensional models with two scalars constructed using a superpotential, we show that a normalizable zero mode survives, even in the presence of warped gravity. Such models, which are widely used in the literature, are therefore phenomenologically unacceptable.

  8. Iron Kα line of Kerr black holes with scalar hair

    NASA Astrophysics Data System (ADS)

    Ni, Yueying; Zhou, Menglei; Cárdenas-Avendaño, Alejandro; Bambi, Cosimo; Herdeiro, Carlos A. R.; Radu, Eugen

    2016-07-01

    Recently, a family of hairy black holes in 4-dimensional Einstein gravity minimally coupled to a complex, massive scalar field was discovered [1]. Besides the mass M and spin angular momentum J, these objects are characterized by a Noether charge Q, measuring the amount of scalar hair, which is not associated to a Gauss law and cannot be measured at spatial infinity. Introducing a dimensionless scalar hair parameter q, ranging from 0 to 1, we recover (a subset of) Kerr black holes for q = 0 and a family of rotating boson stars for q = 1. In the present paper, we explore the possibility of measuring q for astrophysical black holes with current and future X-ray missions. We study the iron Kα line expected in the reflection spectrum of such hairy black holes and we simulate observations with Suzaku and eXTP. As a proof of concept, we point out, by analyzing a sample of hairy black holes, that current observations can already constrain the scalar hair parameter q, because black holes with q close to 1 would have iron lines definitively different from those we observe in the available data. We conclude that a detailed scanning of the full space of solutions, together with data from the future X-ray missions, like eXTP, will be able to put relevant constraints on the astrophysical realization of Kerr black holes with scalar hair.

  9. Growth of spherical overdensities in scalar-tensor cosmologies

    NASA Astrophysics Data System (ADS)

    Nazari-Pooya, N.; Malekjani, M.; Pace, F.; Jassur, D. Mohammad-Zadeh

    2016-06-01

    The accelerated expansion of the universe is a rather established fact in cosmology and many different models have been proposed as a viable explanation. Many of these models are based on the standard general relativistic framework of non-interacting fluids or more recently of coupled (interacting) dark energy models, where dark energy (the scalar field) is coupled to the dark matter component giving rise to a fifth-force. An interesting alternative is to couple the scalar field directly to the gravity sector via the Ricci scalar. These models are dubbed non-minimally coupled models and give rise to a time-dependent gravitational constant. In this work, we study few models falling into this category and describe how observables depend on the strength of the coupling. We extend recent work on the subject by taking into account also the effects of the perturbations of the scalar field and showing their relative importance on the evolution of the mass function. By working in the framework of the spherical collapse model, we show that perturbations of the scalar field have a limited impact on the growth factor (for small coupling constant) and on the mass function with respect to the case where perturbations are neglected.

  10. A Riccati equation based approach to isotropic scalar field cosmologies

    NASA Astrophysics Data System (ADS)

    Harko, Tiberiu; Lobo, Francisco S. N.; Mak, M. K.

    2014-05-01

    Gravitationally coupled scalar fields ϕ, distinguished by the choice of an effective self-interaction potential V(ϕ), simulating a temporarily nonvanishing cosmological term, can generate both inflation and late time acceleration. In scalar field cosmological models the evolution of the Hubble function is determined, in terms of the interaction potential, by a Riccati type equation. In the present work, we investigate scalar field cosmological models that can be obtained as solutions of the Riccati evolution equation for the Hubble function. Four exact integrability cases of the field equations are presented, representing classes of general solutions of the Riccati evolution equation. The solutions correspond to cosmological models in which the Hubble function is proportional to the scalar field potential plus a linearly decreasing function of time, models with the time variation of the scalar field potential proportional to the potential minus its square, models in which the potential is the sum of an arbitrary function and the square of the function integral, and models in which the potential is the sum of an arbitrary function and the derivative of its square root, respectively. The cosmological properties of all models are investigated in detail, and it is shown that they can describe the inflationary or the late accelerating phase in the evolution of the universe.

  11. Iterative structure within the five-particle two-loop amplitude

    SciTech Connect

    Cachazo, Freddy; Spradlin, Marcus; Volovich, Anastasia

    2006-08-15

    We find an unexpected iterative structure within the two-loop five-gluon amplitude in N=4 supersymmetric Yang-Mills theory. Specifically, we show that a subset of diagrams contributing to the full amplitude, including a two-loop pentagon-box integral with nontrivial dependence on five kinematical variables, satisfies an iterative relation in terms of one-loop scalar box diagrams. The implications of this result for the possible iterative structure of the full two-loop amplitude are discussed.

  12. The effect of varying the radiative/convective split for internal gains on cooling load calculations: A case study for the Pentagon

    SciTech Connect

    Liesen, R.J.; Strand, R.K.; Pedersen, C.O.

    1998-10-01

    Two new methods for calculating cooling loads have just been introduced. The first algorithm, called the heat balance (HB) method, is a complete formulation of fundamental heat balance principles. The second is called the radiant time series (RTS) method. While based on the HB method, the RTS method is an approximate procedure that separates some of the processes to better show the influence of individual heat gain components. In the HB method, all of the heat transfer mechanisms participate in three simultaneous heat balances: the balance on the outside face of all the building elements that enclose the space, the balance on the inside face of the building elements, and the balance between the surfaces inside the space and the zone air. The focus of this paper is on the second heat balance. It has been customary to define a radiative/convective split for the heat introduced into a zone from such sources as equipment, lights, people, etc. The radiative part is then distributed over the surfaces within the zone in some prescribed manner, and the convective part is assumed to go immediately into the air. Simplified techniques simply cannot accurately portray the complex interaction of building surfaces, so previously used load calculation procedures were not up to the task of analyzing the effect of internal load radiant/convective split variation. This paper will present an investigation of the influence of the radiative/convective split on cooling loads obtained using the heat balance procedure. It will begin with an overview of the model used for a heat balance procedure and then present an exhaustive case study of the effects of changing the mode split on load calculations for Wedge 1 of the Pentagon building.

  13. Screening of scalar fields in Dirac-Born-Infeld theory

    NASA Astrophysics Data System (ADS)

    Burrage, Clare; Khoury, Justin

    2014-07-01

    We study a new screening mechanism which is present in Dirac-Born-Infeld (DBI)-like theories. A scalar field with a DBI-like Lagrangian is minimally coupled to matter. In the vicinity of sufficiently dense sources, nonlinearities in the scalar dominate and result in an approximately constant acceleration on a test particle, thereby suppressing the scalar force relative to gravity. Unlike generic P(X) or chameleon theories, screening happens within the regime of validity of the effective field theory thanks to the DBI symmetry. We derive an exact form for the field profile around multiple sources and determine the constraints on the theory parameters from tests of gravity. Perturbations around the spherically-symmetric background propagate superluminally, but we argue for a chronology protection analogous to Galileons. This is the first example of a screening mechanism for which quantum corrections to the theory are under control and exact solutions to cosmological N-body problems can be found.

  14. Scalar field breathers on anti-de Sitter background

    NASA Astrophysics Data System (ADS)

    Fodor, Gyula; Forgács, Péter; Grandclément, Philippe

    2014-03-01

    We study spatially localized, time-periodic solutions (breathers) of scalar field theories with various self-interacting potentials on anti-de Sitter (AdS) spacetimes in D dimensions. A detailed numerical study of spherically symmetric configurations in D =3 dimensions is carried out, revealing a rich and complex structure of the phase-space (bifurcations, resonances). Scalar breather solutions form one-parameter families parametrized by their amplitude, ɛ, while their frequency, ω =ω(ɛ), is a function of the amplitude. The scalar breathers on AdS we find have a small amplitude limit, tending to the eigenfunctions of the linear Klein-Gordon operator on AdS. Importantly most of these breathers appear to be generically stable under time evolution.

  15. Loop quantum gravity coupled to a scalar field

    NASA Astrophysics Data System (ADS)

    Lewandowski, Jerzy; Sahlmann, Hanno

    2016-01-01

    We consider the model of gravity coupled to the Klein-Gordon time field. We do not deparametrize the theory using the scalar field before quantization, but quantize all degrees of freedom. Several new results for loop quantum gravity are obtained: (i) a Hilbert space for the gravity-matter system and a nonstandard representation of the scalar field thereon is constructed, (ii) a new operator for the scalar constraint of the coupled system is defined and investigated, (iii) methods for solving the constraint are developed. Commutators of the new quantum constraint operators correspond to the quantization of the Poisson bracket. This, however, poses problems for finding solutions. Hence the states we consider—and perhaps the whole setup—still needs some improvement. As a side result we describe a representation of the gravitational degrees of freedom in which the flux is diagonal. This representation is related to the BF theory vacuum of Dittrich and Geiller.

  16. Optimized scalar promotion with load and splat SIMD instructions

    DOEpatents

    Eichenberger, Alexandre E.; Gschwind, Michael K.; Gunnels, John A.

    2012-08-28

    Mechanisms for optimizing scalar code executed on a single instruction multiple data (SIMD) engine are provided. Placement of vector operation-splat operations may be determined based on an identification of scalar and SIMD operations in an original code representation. The original code representation may be modified to insert the vector operation-splat operations based on the determined placement of vector operation-splat operations to generate a first modified code representation. Placement of separate splat operations may be determined based on identification of scalar and SIMD operations in the first modified code representation. The first modified code representation may be modified to insert or delete separate splat operations based on the determined placement of the separate splat operations to generate a second modified code representation. SIMD code may be output based on the second modified code representation for execution by the SIMD engine.

  17. Optimized scalar promotion with load and splat SIMD instructions

    DOEpatents

    Eichenberger, Alexander E; Gschwind, Michael K; Gunnels, John A

    2013-10-29

    Mechanisms for optimizing scalar code executed on a single instruction multiple data (SIMD) engine are provided. Placement of vector operation-splat operations may be determined based on an identification of scalar and SIMD operations in an original code representation. The original code representation may be modified to insert the vector operation-splat operations based on the determined placement of vector operation-splat operations to generate a first modified code representation. Placement of separate splat operations may be determined based on identification of scalar and SIMD operations in the first modified code representation. The first modified code representation may be modified to insert or delete separate splat operations based on the determined placement of the separate splat operations to generate a second modified code representation. SIMD code may be output based on the second modified code representation for execution by the SIMD engine.

  18. Higgs and gravitational scalar fields together induce Weyl gauge

    NASA Astrophysics Data System (ADS)

    Scholz, Erhard

    2015-02-01

    A common biquadratic potential for the Higgs field and an additional scalar field , non minimally coupled to gravity, is considered in a locally scale symmetric approach to standard model fields in curved spacetime. A common ground state of the two scalar fields exists and couples both fields to gravity, more precisely to Weyl geometric scalar curvature . In Einstein gauge (, often called "Einstein frame"), also is scaled to a constant. This condition makes perfect sense, even in the general case, in the Weyl geometric approach. There it has been called Weyl gauge, because it was first considered by Weyl in the different context of his original scale geometric theory of gravity of 1918. Now it may get new meaning as a combined effect of electroweak theory and gravity, and their common influence on atomic frequencies.

  19. Cosmology in new gravitational scalar-tensor theories

    NASA Astrophysics Data System (ADS)

    Saridakis, Emmanuel N.; Tsoukalas, Minas

    2016-06-01

    We investigate the cosmological applications of new gravitational scalar-tensor theories, which are novel modifications of gravity possessing 2 +2 propagating degrees of freedom, arising from a Lagrangian that includes the Ricci scalar and its first and second derivatives. Extracting the field equations we obtain an effective dark energy sector that consists of both extra scalar degrees of freedom, and we determine various observables. We analyze two specific models and we obtain a cosmological behavior in agreement with observations, i.e. transition from matter to dark energy era, with the onset of cosmic acceleration. Additionally, for a particular range of the model parameters, the equation-of-state parameter of the effective dark energy sector can exhibit the phantom-divide crossing. These features reveal the capabilities of these theories, since they arise solely from the novel, higher-derivative terms.

  20. Thick branes from self-gravitating scalar fields

    SciTech Connect

    Novikov, Oleg O.; Andrianov, Vladimir A.; Andrianov, Alexander A.

    2014-07-23

    The formation of a domain wall ('thick brane') induced by scalar matter dynamics and triggered by a thin brane defect is considered in noncompact five-dimensional space-time with warped AdS type geometry. The scalar matter is composed of two fields with softly broken O(2) symmetry and minimal coupling to gravity. The nonperturbative effects in the invariant mass spectrum of light localized scalar states are investigated for different values of the tension of the thin brane defect. Especially interesting is the case of the thin brane with negative tension when the singular barriers form a potential well with two infinitely tall walls and the discrete spectrum of localized states arises completely isolated from the bulk.

  1. Asymmetric dark matter and the scalar-tensor model

    NASA Astrophysics Data System (ADS)

    Wang, Shun-Zhi; Iminniyaz, Hoernisa; Mamat, Mamatrishat

    2016-03-01

    The relic abundance of asymmetric dark matter particles in the scalar-tensor model is analyzed in this paper. We extend the numerical and analytical calculations of the relic density of the asymmetric dark matter in the standard cosmological scenario to the nonstandard cosmological scenario. We focus on the scalar-tensor model. Hubble expansion rate is changed in the nonstandard cosmological scenario. This leaves its imprint on the relic density of dark matter particles. In this paper we investigate to what extent the asymmetric dark matter particle’s relic density is changed in the scalar-tensor model. We use the observed present day dark matter abundance to find the constraints on the parameter space in this model.

  2. Pulsar timing signal from ultralight scalar dark matter

    SciTech Connect

    Khmelnitsky, Andrei; Rubakov, Valery E-mail: rubakov@ms2.inr.ac.ru

    2014-02-01

    An ultralight free scalar field with mass around 10{sup −23}−10{sup −22} eV is a viable dark mater candidate, which can help to resolve some of the issues of the cold dark matter on sub-galactic scales. We consider the gravitational field of the galactic halo composed out of such dark matter. The scalar field has oscillating in time pressure, which induces oscillations of gravitational potential with amplitude of the order of 10{sup −15} and frequency in the nanohertz range. This frequency is in the range of pulsar timing array observations. We estimate the magnitude of the pulse arrival time residuals induced by the oscillating gravitational potential. We find that for a range of dark matter masses, the scalar field dark matter signal is comparable to the stochastic gravitational wave signal and can be detected by the planned SKA pulsar timing array experiment.

  3. Color sextet scalars at the CERN Large Hadron Collider

    SciTech Connect

    Chen, C.-R.; Klemm, William; Rentala, Vikram; Wang Kai

    2009-03-01

    Taking a phenomenological approach, we study a color sextet scalar at the LHC. We focus on the QCD production of a color sextet pair {phi}{sub 6}{phi}{sub 6} through gg fusion and qq annihilation. Its unique coupling to {psi}{sup c}{psi} allows the color sextet scalar to decay into same-sign diquark states, such as {phi}{sub 6}{yields}tt/tt*. We propose a new reconstruction in the multijet plus same-sign dilepton with missing transverse energy samples (bb+l{sup {+-}}l{sup {+-}}+Ee{sub T}+Nj, N{>=}6) to search for on-shell tttt final states from sextet scalar pair production. Thanks to the large QCD production, the search covers the sextet mass range up to 1 TeV for 100 fb{sup -1} integrated luminosity.

  4. Primordial scalar power spectrum from the Euclidean big bounce

    NASA Astrophysics Data System (ADS)

    Schander, Susanne; Barrau, Aurélien; Bolliet, Boris; Linsefors, Linda; Mielczarek, Jakub; Grain, Julien

    2016-01-01

    In effective models of loop quantum cosmology, the holonomy corrections are associated with deformations of space-time symmetries. The most evident manifestation of the deformations is the emergence of a Euclidean phase accompanying the nonsingular bouncing dynamics of the scale factor. In this article, we compute the power spectrum of scalar perturbations generated in this model, with a massive scalar field as the matter content. Instantaneous and adiabatic vacuum-type initial conditions for scalar perturbations are imposed in the contracting phase. The evolution through the Euclidean region is calculated based on the extrapolation of the time direction pointed by the vectors normal to the Cauchy hypersurface in the Lorentzian domains. The obtained power spectrum is characterized by a suppression in the IR regime and oscillations in the intermediate energy range. Furthermore, the speculative extension of the analysis in the UV reveals a specific rise of the power leading to results incompatible with the data.

  5. 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.

  6. Adjunctation and Scalar Product in the Dirac Equation - I

    NASA Astrophysics Data System (ADS)

    Dima, M.

    2016-02-01

    The Bargmann-Pauli adjunctator (hermitiser) of {C}{l}_{_{1,3}}(C) is derived in a representation independent way, circumventing the early derivations (Pauli, Ann. inst. Henri Poincaré 6, 109 and 121 1936) using representation-dependent arguments. Relations for the adjunctator's transformation with the scalar product and space generator set are given. The S U(2) adjunctator is shown to determine the {C}{l}_{_{1,3}}(C) adjunctator. Part-II of the paper will approach the problem of the two scalar products used in Dirac theory - an unphysical situation of "piece-wise physics" with erroneous results. The adequate usage of scalar product - via calibration - will be presented, in particular under boosts, yielding the known covariant transformations of physical quantities.

  7. Chiral Loops and Ghost States in the Quenched Scalar Propagator

    SciTech Connect

    W. Bardeen; A. Duncan; E. Eichten; N. Isgur; H. Thacker

    2001-06-01

    The scalar, isovector meson propagator is analyzed in quenched QCD, using the MQA pole-shifting ansatz to study the chiral limit. In addition to the expected short-range exponential falloff characteristic of a heavy scalar meson, the propagator also exhibits a longer-range, negative metric contribution which becomes pronounced for smaller quark masses. We show that this is a quenched chiral loop effect associated with the anomalous structure of the eta' propagator in quenched QCD. Both the time dependence and the quark mass dependence of this effect are well-described by a chiral loop diagram corresponding to an eta'-pi intermediate state, which is light and effectively of negative norm in the quenched approximation. The relevant parameters of the effective Lagrangian describing the scalar sector of the quenched theory are determined.

  8. Thermodynamics of perfect fluids from scalar field theory

    NASA Astrophysics Data System (ADS)

    Ballesteros, Guillermo; Comelli, Denis; Pilo, Luigi

    2016-07-01

    The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields. These scalars describe the embedding in spacetime of the medium and play the role of Stückelberg fields for spontaneously broken spatial and time translations. Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar. We explore the relation between the field theory description of perfect fluids to thermodynamics. By drawing the correspondence between the allowed operators at leading order in derivatives and the thermodynamic variables, we find that a complete thermodynamic picture requires the four Stückelberg fields. We show that thermodynamic stability plus the null-energy condition imply dynamical stability. We also argue that a consistent thermodynamic interpretation is not possible if any of the shift symmetries is explicitly broken.

  9. Detecting chameleons: The astronomical polarization produced by chameleonlike scalar fields

    SciTech Connect

    Burrage, Clare; Davis, Anne-Christine; Shaw, Douglas J.

    2009-02-15

    We show that a coupling between chameleonlike scalar fields and photons induces linear and circular polarization in the light from astrophysical sources. In this context chameleonlike scalar fields include those of the Olive-Pospelov (OP) model, which describes a varying fine structure constant. We determine the form of this polarization numerically and give analytic expressions in two useful limits. By comparing the predicted signal with current observations we are able to improve the constraints on the chameleon-photon coupling and the coupling in the OP model by over 2 orders of magnitude. It is argued that, if observed, the distinctive form of the chameleon induced circular polarization would represent a smoking gun for the presence of a chameleon. We also report a tentative statistical detection of a chameleonlike scalar field from observations of starlight polarization in our galaxy.

  10. An inflationary model with small scalar and large tensor nongaussianities

    SciTech Connect

    Cook, Jessica L.; Sorbo, Lorenzo E-mail: sorbo@physics.umass.edu

    2013-11-01

    We study a model of inflation where the scalar perturbations are almost gaussian while there is sizable (equilateral) nongaussianity in the tensor sector. In this model, a rolling pseudoscalar gravitationally coupled to the inflaton amplifies the vacuum fluctuations of a vector field. The vector sources both scalar and tensor metric perturbations. Both kinds of perturbations are nongaussian, but, due to helicity conservation, the tensors have a larger amplitude, so that nongaussianity in the scalar perturbations is negligible. Moreover, the tensors produced this way are chiral. We study, in the flat sky approximation, how constraints on tensor nongaussianities affect the detectability of parity violation in the Cosmic Microwave Background. We expect the model to feature interesting patterns on nongaussianities in the polarization spectra of the CMB.

  11. Extended scalar-tensor theory and thermodynamics in teleparallel framework

    NASA Astrophysics Data System (ADS)

    Salti, Mustafa; Aydogdu, Oktay; Acikgoz, Irfan

    2016-09-01

    We present here a new modified gravitation theory for the galactic dark energy effect by using a general Lagrangian density which is represented by an arbitrary function f(T, ϕ, X) where T describes the torsion scalar in teleparallel gravity while X shows the kinetic scalar field energy. While the function is in general form, once reduced, the model can be transformed into some of the other well-known gravitation theories. After deriving the corresponding field equations and considering the flat Friedmann-Robertson-Walker type universe which is filled with ordinary cosmic matter, we discuss both the non-equilibrium and equilibrium profiles of galactic thermodynamics. We find that there exists an equilibrium picture of thermodynamics. Additionally, we also generalize ordinary f(T, ϕ, X) model’s action to the case in which there exists an interaction between the chameleon and scalar fields.

  12. Scalar Aharonov-Bohm effect with longitudinally polarized neutrons

    SciTech Connect

    Allman, B. E.; Lee, W.-T.; Motrunich, O. I.; Werner, S. A.

    1999-12-01

    In the scalar Aharonov-Bohm effect, a charged particle (electron) interacts with the scalar electrostatic potential U in the field-free (i.e., force-free) region inside an electrostatic cylinder (Faraday cage). Using a perfect single-crystal neutron interferometer we have performed a ''dual'' scalar Aharonov-Bohm experiment by subjecting polarized thermal neutrons to a pulsed magnetic field. The pulsed magnetic field was spatially uniform, precluding any force on the neutrons. Aligning the direction of the pulsed magnetic field to the neutron magnetic moment also rules out any classical torque acting to change the neutron polarization. The observed phase shift is purely quantum mechanical in origin. A detailed description of the experiment, performed at the University of Missouri Research Reactor, and its interpretation is given in this paper. (c) 1999 The American Physical Society.

  13. Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV.

    PubMed

    Affolder, T; Akimoto, H; Akopian, A; Albrow, M G; Amaral, P; Amendolia, S R; Amidei, D; Anikeev, K; Antos, J; Apollinari, G; Arisawa, T; Asakawa, T; Ashmanskas, W; Atac, M; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bailey, M W; Bailey, S; de Barbaro, P; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barone, M; Bauer, G; Bedeschi, F; Belforte, S; Bellettini, G; Bellinger, J; Benjamin, D; Bensinger, J; Beretvas, A; Berge, J P; Berryhill, J; Bertolucci, S; Bevensee, B; Bhatti, A; Bigongiari, C; Binkley, M; Bisello, D; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Blusk, B S; Bocci, A; Bodek, A; Bokhari, W; Bolla, G; Bonushkin, Y; Bortoletto, D; Boudreau, J; Brandl, A; van den Brink, S; Bromberg, C; Brozovic, M; Bruner, N; Buckley-Geer, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Byon-Wagner, A; Byrum, K L; Campbell, M; Caner, A; Carithers, W; Carlson, J; Carlsmith, D; Cassada, J; Castro, A; Cauz, D; Cerri, A; Chan, A W; Chang, P S; Chang, P T; Chapman, J; Chen, C; Chen, Y C; Cheng, M T; Chertok, M; Chiarelli, G; Chirikov-Zorin, I; Chlachidze, G; Chlebana, F; Christofek, L; Chu, M L; Cihangir, S; Ciobanu, C I; Clark, A G; Cobal, M; Cocca, E; Connolly, A; Conway, J; Cooper, J; Cordelli, M; Costanzo, D; Cranshaw, J; Cronin-Hennessy, D; Cropp, R; Culbertson, R; Dagenhart, D; DeJongh, F; Dell'Agnello, S; Dell'Orso, M; Demina, R; Demortier, L; Deninno, M; Derwent, P F; Devlin, T; Dittmann, J R; Donati, S; Done, J; Dorigo, T; Eddy, N; Einsweiler, K; Elias, J E; Engels, E; Erdmann, W; Errede, D; Errede, S; Fan, Q; Feild, R G; Ferretti, C; Fiori, I; Flaugher, B; Foster, G W; Franklin, M; Freeman, J; Friedman, J; Fukui, Y; Galeotti, S; Gallinaro, M; Gao, T; Garcia-Sciveres, M; Garfinkel, A F; Gatti, P; Gay, C; Geer, S; Gerdes, D W; Giannetti, P; Giromini, P; Glagolev, V; Gold, M; Goldstein, J; Gordon, A; Goshaw, A T; Gorta, Y; Goulianos, K; Grassmann, H; Green, C; Groer, L; Grosso-Pilcher, C; Guenther, M; Guillian, G; Guimaraes da Costa, J; Guo, R S; Haber, C; Hafen, E; Hahn, S R; Hall, C; Handa, T; Handler, R; Hao, W; Happacher, F; Hara, K; Hardman, A D; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Heinrich, J; Heiss, A; Hinrichsen, B; Hoffman, K D; Holck, C; Hollebeek, R; Holloway, L; Hughes, R; Huston, J; Huth, J; Ikeda, H; Incagli, M; Incandela, J; Introzzi, G; Iwai, J; Iwata, Y; James, E; Jensen, H; Jones, M; Joshi, U; Kambara, H; Kamon, T; Kaneko, T; Karr, K; Kasha, H; Kato, Y; Keaffaber, T A; Kelley, K; Kelly, M; Kennedy, R D; Kephart, R; Khazins, D; Kikuchi, T; Kirk, M; Kim, B J; Kim, H S; Kim, M J; Kim, S H; Kim, Y K; Kirsch, L; Klimenko, S; Knoblauch, D; Koehn, P; Köngeter, A; Kondo, K; Konigsberg, J; Kordas, K; Korn, A; Korytov, A; Kovacs, E; Kroll, J; Kruse, M; Kuhlmann, S E; Kurino, K; Kuwabara, T; Laasanen, A T; Lai, N; Lami, S; Lammel, S; Lamoureux, J I; Lancaster, M; Latino, G; LeCompte, T; Lee, A M; Leone, S; Lewis, J D; Lindgren, M; Liss, T M; Liu, J B; Liu, Y C; Lockyer, N; Loken, J; Loreti, M; Lucchesi, D; Lukens, P; Lusin, S; Lyons, L; Lys, J; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Mangano, M; Mariotti, M; Martignon, G; Martin, A; Matthews, J A; Mazzanti, P; McFarland, K S; McIntyre, P; McKigney, E; Menguzzato, M; Mezione, A; Meschi, E; Mesropian, C; Miao, C; Miao, T; Miller, R; Miller, J S; Minato, H; Miscetti, S; Mishina, M; Moggi, N; Moore, E; Moore, R; Morita, Y; Mukherjee, A; Muller, T; Munar, A; Murat, P; Murgia, S; Musy, M; Nachtman, J; Nahn, S; Nakada, H; Nakaya, T; Nakano, I; Nelson, C; Neuberger, D; Newman-Holmes, C; Ngan, C Y; Nicolaidi, P; Niu, H; Nodulman, L; Nomerotski, A; Oh, S H; Ohmoto, T; Ohsugi, T; Oishi, R; Okusawa, T; Olsen, J; Pagliarone, C; Palmonari, F; Paoletti, R; Papadimitriou, V; Pappas, S P; Parri, A; Partos, D; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Perazzo, A; Pescara, L; Phillips, T J; Piacentino, G; Pitts, K T; Plunkett, R; Pompos, A; Pondrom, L; Pope, G; Popovic, M; Prokoshin, F; Proudfoot, J; Ptohos, F; Punzi, G; Ragan, K; Rakitine, A; Reher, D; Reichold, A; Riegler, W; Ribon, A; Rimondi, F; Ristori, L; Robertson, W J; Robinson, A; Rodrigo, T; Rolli, S; Rosenson, L; Roser, R; Rossin, R; Sakumoto, W K; Saltzberg, D; Sansoni, A; Santi, L; Sato, H; Savard, P; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Scodellaro, L; Scott, A; Scribano, A; Segler, S; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Shah, T; Shapiro, M D; Shepard, P F; Shibayama, T; Shimojima, M; Shochet, M; Siegrist, J; Signorelli, G; Sill, A; Sinervo, P; Singh, P; Slaughter, A J; Sliwa, K; Smith, C; Snider, F D; Solodsky, A; Spalding, J; Speer, T; Sphicas, P; Spinella, F; Spiropulu, M; Spiegel, L; Stanco, L; Steele, J; Stefanini, A; Strologas, J; Strumia, F; Stuart, D; Sumorok, K; Suzuki, T; Takashima, R; Takikawa, K; Tanaka, M; Takano, T; Tannenbaum, B; Taylor, W; Tecchio, M; Teng, P K; Terashi, K; Tether, S; Theriot, D; Thurman-Keup, R; Tipton, P; Tkaczyk, S; Tollefson, K; Tollestrup, A; Toyoda, H; Trischuk, W; de Troconiz, J F; Truitt, S; Tseng, J; Turini, N; Ukegawa, F; Valls, J; Vejcik, S; Velev, G; Vidal, R; Vilar, R; Vologouev, I; Vucinic, D; Wagner, R G; Wagner, R L; Wahl, J; Wallace, N B; Walsh, A M; Wang, C; Wang, C H; Wang, M J; Watanabe, T; Waters, D; Watts, T; Webb, R; Wenzel, H; Wester, W C; Wicklund, A B; Wicklund, E; Williams, H H; Wilson, P; Winer, B L; Winn, D; Wolbers, S; Wolinski, D; Wolinski, J; Worm, S; Wu, X; Wyss, J; Yagil, A; Yao, W; Yeh, G P; Yeh, P; Yoh, J; Yosef, C; Yoshida, T; Yu, I; Yu, S; Zanetti, A; Zetti, F; Zucchelli, S

    2000-06-19

    We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

  14. Scalar field cosmology via non-local integrals of motion

    NASA Astrophysics Data System (ADS)

    Dimakis, N.

    2016-08-01

    In re-parametrization invariant systems, such as mini-superspace Lagrangians, the existence of constraints can lead to the emergence of additional non-local integrals of motion defined in phase space. In the case of a FLRW flat/non-flat space-time minimally coupled to an arbitrary scalar field, we manage to use such conserved quantities to completely integrate the system of equations of motion. This is achieved without constraining the potential in any way. Thus, obtaining the most general solution that encompasses all possible cosmological scenarios which can be based on the existence of a scalar field.

  15. Production of scalar and tensor perturbations in inflationary models

    NASA Astrophysics Data System (ADS)

    Turner, Michael S.

    1993-10-01

    Scalar (density) and tensor (gravity-wave) perturbations provide the basis for the fundamental observable consequences of inflation, including CBR anisotropy and the formation of structure in the Universe. These perturbations are nearly scale invariant (Harrison-Zel'dovich spectrum), though a slight deviation from scale invariance (``tilt'') can have significant consequences for both CBR anisotropy and structure formation. In particular, a slightly tilted spectrum of scalar perturbations may improve the agreement of the cold dark matter scenario with the observational data. The amplitude and spectrum of the scalar and tensor perturbations depend upon the shape of the inflationary potential in the small interval where the scalar field responsible for inflation was between about 46 and 54 e-folds before the end of inflation. By expanding the inflationary potential in a Taylor series over this interval we show that the amplitudes of the perturbations and the power-law slopes of their spectra can be expressed in terms of the value of the potential 50 e-folds before the end of inflation, V50, its steepness x50≡mPlV'50/V50, and the rate of change of its steepness, x'50 (a prime denotes a derivative with respect to the scalar field). In addition, the power-law index of the cosmic-scale factor at this time is q50≡[dlnR/dlnt]50~=16π/x250. (Formally, our results for the perturbation amplitudes and spectral indices are accurate to lowest order in the deviation from scale invariance.) In general, the deviation from scale invariance is such to enhance fluctuations on large scales, and is only significant for steep potentials, large x50, or potentials with rapidly changing steepness, large x'50. In the latter case, only the spectrum of scalar perturbations is significantly tilted. Steep potentials are characterized by a large tensor-mode contribution to the quadrupole CBR temperature anisotropy, a similar tilt in both scalar and tensor perturbations, and a slower expansion

  16. Searches for scalar and vector leptoquarks at future hadron colliders

    SciTech Connect

    Rizzo, T.G.

    1996-09-01

    The search reaches for both scalar(S) and vector(V) leptoquarks at future hadron colliders are summarized. In particular the authors evaluate the production cross sections of both leptoquark types at TeV33 and LHC as well as the proposed 60 and 200 TeV colliders through both quark-antiquark annihilation and gluon-gluon fusion: q{anti q},gg {r_arrow} SS,VV. Experiments at these machines should easily discover such particles if their masses are not in excess of the few TeV range.

  17. Composite (pseudo) scalar contributions to muon g - 2

    NASA Astrophysics Data System (ADS)

    Hong, Deog Ki; Kim, Du Hwan

    2016-07-01

    We have calculated the composite (pseudo) scalar contributions to the anomalous magnetic moment of muons in models of walking technicolor. By the axial or scale anomaly the light scalars such as techni-dilaton, techni-pions or techni-eta have anomalous couplings to two-photons, which make them natural candidates for the recent 750 GeV resonance excess, observed at LHC. Due to the anomalous couplings, their contributions to muon (g - 2) are less suppressed and might explain the current deviation in muon (g - 2) measurements from theory.

  18. Analysis of the scalar nonet mesons with QCD sum rules

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Gang

    2016-08-01

    In this article, we assume that the nonet scalar mesons below 1 GeV are the two-quark-tetraquark mixed states and study their masses and pole residues using the QCD sum rules. In the calculation, we take into account the vacuum condensates up to dimension 10 and the O(α _s) corrections to the perturbative terms in the operator product expansion. We determine the mixing angles, which indicate the two-quark components are much larger than 50~%, then we obtain the masses and pole residues of the nonet scalar mesons.

  19. Unified description of the dynamics of quintessential scalar fields

    SciTech Connect

    Ureña-López, L. Arturo

    2012-03-01

    Using the dynamical system approach, we describe the general dynamics of cosmological scalar fields in terms of critical points and heteroclinic lines. It is found that critical points describe the initial and final states of the scalar field dynamics, but that heteroclinic lines give a more complete description of the evolution in between the critical points. In particular, the heteroclinic line that departs from the (saddle) critical point of perfect fluid-domination is the representative path in phase space of quintessence fields that may be viable dark energy candidates. We also discuss the attractor properties of the heteroclinic lines, and their importance for the description of thawing and freezing fields.

  20. Generalized Scalar Duffin-Kemmer-Petiau Electrodynamics (GSDKP)

    NASA Astrophysics Data System (ADS)

    Bufalo, R.; Cardoso, T. R.; Nogueira, A. A.; Pimentel, B. M.

    2016-04-01

    The main goal of this work is to investigate the quantum interaction between scalar field and gauge field in the context of Generalized Scalar Duffin-Kemmer-Petiau Electrodynamics (GSDKP) by a quantum theory in the functional approach. The Hamiltonian structure is obtained with the Dirac method and the Faddeev-Senjanovic procedure is established in order to write the transition amplitude in an alternative gauge fixing, known as the non-mixing gauge. As a consequence, the Schwinger-Dyson-Fradkin equations and the Ward-Takahashi-Fradkin identities are obtained.

  1. Stable hypersurfaces with zero scalar curvature in Euclidean space

    NASA Astrophysics Data System (ADS)

    Alencar, Hilário; do Carmo, Manfredo; Neto, Gregório Silva

    2016-10-01

    In this paper we prove some results concerning stability of hypersurfaces in the four dimensional Euclidean space with zero scalar curvature. First we prove there is no complete stable hypersurface with zero scalar curvature, polynomial growth of integral of the mean curvature, and with the Gauss-Kronecker curvature bounded away from zero. We conclude this paper giving a sufficient condition for a regular domain to be stable in terms of the mean and the Gauss-Kronecker curvatures of the hypersurface and the radius of the smallest extrinsic ball which contains the domain.

  2. Anisotropic exact solutions in scalar-tensor-vector gravity

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Yousaf, Aasma

    2016-09-01

    The aim of this paper is to explore exact solutions in the scalar-tensor-vector theory of gravity with two scalar fields and one vector field. We consider a locally rotationally symmetric Bianchi type-I universe filled with perfect fluid. The first exact solution is found through certain assumptions while the second solution is obtained through Noether symmetry approach. We discuss the behavior of the resulting solutions numerically and also explore the corresponding energy conditions. It is found that the strong energy condition is violated in both cases indicating the accelerated expansion of the universe.

  3. Very light cosmological scalar fields from a tiny cosmological constant

    SciTech Connect

    Calmet, Xavier

    2007-10-15

    I discuss a mechanism which generates a mass term for a scalar field in an expanding universe. The mass of this field turns out to be generated by the cosmological constant and can be naturally small if protected by a conformal symmetry which is, however, broken in the gravitational sector. The mass is comparable today to the Hubble time. This scalar field could thus impact our Universe today and, for example, be at the origin of a time variation of the couplings and masses of the parameters of the standard model.

  4. On the stability and causality of scalar-vector theories

    SciTech Connect

    Fleury, Pierre; Pitrou, Cyril; Uzan, Jean-Philippe; Almeida, Juan P. Beltrán E-mail: juanpbeltran@uan.edu.co E-mail: uzan@iap.fr

    2014-11-01

    Various extensions of standard inflationary models have been proposed recently by adding vector fields. Because they are generally motivated by large-scale anomalies, and the possibility of statistical anisotropy of primordial fluctuations, such models require to introduce non-standard couplings between vector fields on the one hand, and either gravity or scalar fields on the other hand. In this article, we study models involving a vector field coupled to a scalar field. We derive restrictive necessary conditions for these models to be both stable (Hamiltonian bounded by below) and causal (hyperbolic equations of motion)

  5. Scalar-tensor theory of gravitation with negative coupling constant

    NASA Technical Reports Server (NTRS)

    Smalley, L. L.; Eby, P. B.

    1976-01-01

    The possibility of a Brans-Dicke scalar-tensor gravitation theory with a negative coupling constant is considered. The admissibility of a negative-coupling theory is investigated, and a simplified cosmological solution is obtained which allows a negative derivative of the gravitation constant. It is concluded that a Brans-Dicke theory with a negative coupling constant can be a viable alternative to general relativity and that a large negative value for the coupling constant seems to bring the original scalar-tensor theory into close agreement with perihelion-precession results in view of recent observations of small solar oblateness.

  6. Braneworld inflation with a complex scalar field from Planck 2015

    NASA Astrophysics Data System (ADS)

    Mounzi, Z.; Ferricha-Alami, M.; Chakir, H.; Bennai, M.

    2016-06-01

    We study an inflationary model with a single complex scalar field in the framework of braneworld Randall-Sundrum model type 2. From the scalar curvature perturbation constrained by the recent observation values, and for specific choice of parameters, we can reduce the values of the coupling constant to take the natural values, and we found that the phase theta θ of the inflation field can take the narrow interval. We have also derived all known inflationary parameters (ns, r and dns/d ln (k)), which are widely consistent with the recent Planck data for a suitable choice of brane tension value λ.

  7. Gravity quantized: Loop quantum gravity with a scalar field

    SciTech Connect

    Domagala, Marcin; Kaminski, Wojciech; Giesel, Kristina; Lewandowski, Jerzy

    2010-11-15

    ...''but we do not have quantum gravity.'' This phrase is often used when analysis of a physical problem enters the regime in which quantum gravity effects should be taken into account. In fact, there are several models of the gravitational field coupled to (scalar) fields for which the quantization procedure can be completed using loop quantum gravity techniques. The model we present in this paper consists of the gravitational field coupled to a scalar field. The result has similar structure to the loop quantum cosmology models, except that it involves all the local degrees of freedom of the gravitational field because no symmetry reduction has been performed at the classical level.

  8. Quantum supersymmetric FRW cosmology with a scalar field

    NASA Astrophysics Data System (ADS)

    Ramírez, C.; Vázquez-Báez, V.

    2016-02-01

    We analyze the quantum supersymmetric cosmological Friedmann-Robertson-Walker model with a scalar field, with a conditional probability density and the scalar field identified as time. The Hilbert space has a spinorial structure and there is only one consistent solution, with a conserved probability density. The dynamics of the scale factor is obtained from its mean value. The uncertainty relations are fulfilled and the corresponding fluctuations are consistent with a semiclassical Universe. We give two examples which turn out to have negative potential.

  9. Spinning Particles in Scalar-Tensor Gravity with Torsion

    SciTech Connect

    Wang, C.-H.

    2008-10-10

    A new model of neutral spinning particles in scalar-tensor gravity with torsion is developed by using a Fermi coordinates associated with orthonormal frames attached to a timelike curve and Noether identities. We further analyze its equations of motion both in background Brans-Dicke torsion field and the constant pseudo-Riemannian curvature with a constant scalar field. It turns that the particle's spin vector is parallel transport along its wordline in the Brans-Dicke torsion field and de Sitter spacetime. However, the dynamics of the spinning particle cannot completely determined in anti-de Sitter spacetime and it requires a further investigation.

  10. Higgs particles interacting via a scalar Dark Matter field

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Yajnavalkya; Darewych, Jurij

    2016-07-01

    We study a system of two Higgs particles, interacting via a scalar Dark Matter mediating field. The variational method in the Hamiltonian formalism of QFT is used to derive relativistic wave equations for the two-Higgs system, using a truncated Fock-space trial state. Approximate solutions of the two-body equations are used to examine the existence of Higgs bound states.

  11. Kinetic mixing in scalar-tensor theories of gravity

    NASA Astrophysics Data System (ADS)

    Bettoni, Dario; Zumalacárregui, Miguel

    2015-05-01

    Kinetic mixing between the metric and scalar degrees of freedom is an essential ingredient in contemporary scalar-tensor theories. This often makes it hard to understand their physical content, especially when derivative mixing is present, as is the case for Horndeski action. In this work we develop a method that allows us to write a Ricci-curvature-free scalar field equation, and we discuss some of the advantages of such a rephrasing in the study of stability issues in the presence of matter, the existence of an Einstein frame, and the generalization of the disformal screening mechanism. For quartic Horndeski theories, such a procedure leaves, in general, a residual coupling to the curvature, given by the Weyl tensor. This gives rise to a binary classification of scalar-tensor theories into stirred theories, in which the curvature can be substituted, and shaken theories, in which a residual coupling to the curvature remains. Quite remarkably, we have found that generalized Dirac-Born-Infeld Galileons belong to the first class. Finally, we discuss kinetic mixing in quintic theories, in which nonlinear mixing terms appear, and in the recently proposed theories beyond Horndeski that display a novel form of kinetic mixing, in which the field equation is sourced by derivatives of the energy-momentum tensor.

  12. Dwarf galaxies in multistate scalar field dark matter halos

    NASA Astrophysics Data System (ADS)

    Martinez-Medina, L. A.; Robles, V. H.; Matos, T.

    2015-01-01

    We analyze the velocity dispersion for eight of the Milky Way dwarf spheroidal satellites in the context of finite temperature scalar field dark matter. In this model the finite temperature allows the scalar field to be in configurations that possess excited states, a feature that has proved to be necessary in order to explain the asymptotic rotational velocities found in low surface brightness (LSB) galaxies. In this work we show that excited states are not only important in large galaxies but also have visible effects in dwarf spheroidals. Additionally, we stress that contrary to previous works where the scalar field dark matter halos are consider to be purely Bose-Einstein condensates, the inclusion of excited states in these halo configurations provides a consistent framework capable of describing LSB and dwarf galaxies of different sizes without arriving to contradictions within the scalar field dark matter model. Using this new framework we find that the addition of excited states accounts very well for the raise in the velocity dispersion in Milky Way dwarf spheroidal galaxies improving the fit compared to the one obtained assuming all the dark matter to be in the form of a Bose-Einstein condensate.

  13. Direct Searches for Scalar Leptoquarks at the Run II Tevatron

    SciTech Connect

    Ryan, Daniel Edward

    2004-08-01

    This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analyzed has a total time-integrated measured luminosity of 198 pb-1 of p$\\bar{p}$ collisions with √s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. They consider two possible leptoquark decays: (1) β = BR(LQ → μq) = 1.0, and (2) β = BR(LQ → μq) = 0.5. For the β = 1 channel, they focus on the signature represented by two isolated high-pT muons and two isolated high-pT jets. For the β = 1/2 channel, they focus on the signature represented by one isolated high-pT muon, large missing transverse energy, and two isolated high-pT jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in p$\\bar{p}$ collisions [1], they set new mass limits on second generation scalar leptoquarks. They exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c2 for the β = 1(1/2) channels.

  14. Dilaton gravity, (quasi-) black holes, and scalar charge

    NASA Astrophysics Data System (ADS)

    Bronnikov, K. A.; Fabris, J. C.; Silveira, R.; Zaslavskii, O. B.

    2014-09-01

    We consider static electrically charged dust configurations in the framework of Einstein-Maxwell-dilaton gravity with the interaction term P(\\chi) F_{mn} F^{mn} in the Lagrangian, where P(\\chi) is an arbitrary function of the dilaton field \\chi, and the latter is allowed to be normal or phantom. It is shown that, for any regular P(\\chi), static configurations are possible with arbitrary functions g_{00} = e^{2\\gamma(x^i)} (i=1,2,3) and \\chi = \\chi(\\gamma), without any assumption of spatial symmetry. The corresponding matter, electric charge and scalar charge densities are found from the field equations. Meanwhile, configurations with nontrivial \\chi(x^i) generically require a nonzero scalar charge density distribution. The classical Majumdar-Papapetrou (MP) system is obtained as a special case where \\chi = const; there is its scalar analogue in the case F_{mn} = 0, but only with a phantom \\chi field. Among possible solutions are black-hole (BH) and quasi-black-hole (QBH) ones. Some general results on QBH properties obtained previously for the MP system are here extended to systems with the dilaton. Particular examples of asymptotically flat spherically symmetric BH and QBH solutions are found, some of them being phantom-free, that is, exist with positive energy densities of matter and both scalar and electromagnetic fields.

  15. Classification of scalar and dyadic nonlocal optical response models.

    PubMed

    Wubs, M

    2015-11-30

    Nonlocal optical response is one of the emerging effects on the nanoscale for particles made of metals or doped semiconductors. Here we classify and compare both scalar and tensorial nonlocal response models. In the latter case the nonlocality can stem from either the longitudinal response, the transverse response, or both. In phenomenological scalar models the nonlocal response is described as a smearing out of the commonly assumed infinitely localized response, as characterized by a distribution with a finite width. Here we calculate explicitly whether and how tensorial models, such as the hydrodynamic Drude model and generalized nonlocal optical response theory, follow this phenomenological description. We find considerable differences, for example that nonlocal response functions, in contrast to simple distributions, assume negative and complex values. Moreover, nonlocal response regularizes some but not all diverging optical near fields. We identify the scalar model that comes closest to the hydrodynamic model. Interestingly, for the hydrodynamic Drude model we find that actually only one third (1/3) of the free-electron response is smeared out nonlocally. In that sense, nonlocal response is stronger for transverse and scalar nonlocal response models, where the smeared-out fractions are 2/3 and 3/3, respectively. The latter two models seem to predict novel plasmonic resonances also below the plasma frequency, in contrast to the hydrodynamic model that predicts standing pressure waves only above the plasma frequency. PMID:26698757

  16. Physical Scalar Mass Particles in the 331 Model

    SciTech Connect

    Ravinez, O.; Diaz, H.; Romero, D.

    2007-10-26

    We get to diagonalize the mass matrix considering all terms in the scalar lagrangian sector, given in the SU(3)xSU(3)xU(1) model cited below. This will let us in the future realize the phenomenological consequences.

  17. Stability of sticky particle dynamics and related scalar conservation laws

    NASA Astrophysics Data System (ADS)

    Moutsinga, Octave

    2009-06-01

    We show the stability of the sticky particle forward flow (x, s, t) [↦]{phi} (x, s, Pt, ut) w.r.t. perturbations of the initial mass distribution P0 and velocity function u0. Then, we deduce the stability of related scalar conservation laws and pressureless gas system.

  18. Impact of other scalar fields on oscillons after hilltop inflation

    NASA Astrophysics Data System (ADS)

    Antusch, Stefan; Orani, Stefano

    2016-03-01

    Oscillons are spatially localized and relatively stable field fluctuations which can form after inflation under suitable conditions. In order to reheat the universe, the fields which dominate the energy density after inflation have to couple to other degrees of freedom and finally produce the matter particles present in the universe today. In this study, we use lattice simulations in 2+1 dimensions to investigate how such couplings can affect the formation and stability of oscillons. We focus on models of hilltop inflation, where we have recently shown that hill crossing oscillons generically form, and consider the coupling to an additional scalar field which, depending on the value of the coupling parameter, can get resonantly enhanced from the inhomogeneous inflaton field. We find that three cases are realized: without a parametric resonance, the additional scalar field has no effects on the oscillons. For a fast and strong parametric resonance of the other scalar field, oscillons are strongly suppressed. For a delayed parametric resonance, on the other hand, the oscillons get imprinted on the other scalar field and their stability is even enhanced compared to the single-field oscillons.

  19. Second-order accurate nonoscillatory schemes for scalar conservation laws

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1989-01-01

    Explicit finite difference schemes for the computation of weak solutions of nonlinear scalar conservation laws is presented and analyzed. These schemes are uniformly second-order accurate and nonoscillatory in the sense that the number of extrema of the discrete solution is not increasing in time.

  20. Exact null controllability of degenerate evolution equations with scalar control

    SciTech Connect

    Fedorov, Vladimir E; Shklyar, Benzion

    2012-12-31

    Necessary and sufficient conditions for the exact null controllability of a degenerate linear evolution equation with scalar control are obtained. These general results are used to examine the exact null controllability of the Dzektser equation in the theory of seepage. Bibliography: 13 titles.