Charmless B→PP decays using flavor SU(3) symmetry

NASA Astrophysics Data System (ADS)

Chiang, Cheng-Wei; Gronau, Michael; Rosner, Jonathan L.; Suprun, Denis A.

2004-08-01

The decays of B mesons to a pair of charmless pseudoscalar (P) mesons are analyzed within a framework of flavor SU(3). Symmetry breaking is taken into account in tree (T) amplitudes through ratios of decay constants; exact SU(3) is assumed elsewhere. Acceptable fits to B→ππ and B→Kπ branching ratios and CP asymmetries are obtained with tree, color-suppressed (C), penguin (P), and electroweak penguin (PEW) amplitudes. Crucial additional terms for describing processes involving η and η' include a large flavor-singlet penguin amplitude (S) as proposed earlier and a penguin amplitude Ptu associated with intermediate t and u quarks. For the B+→π+η' mode a term Stu associated with intermediate t and u quarks also may be needed. Values of the weak phase γ are obtained consistent with an earlier analysis of B→VP decays, where V denotes a vector meson, and with other analyses of CKM parameters.

The chiral magnetic effect and chiral symmetry breaking in SU(3) quenched lattice gauge theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braguta, V. V., E-mail: braguta@mail.ru; Buividovich, P. V., E-mail: buividovich@itep.ru; Kalaydzhyan, T., E-mail: tigran.kalaydzhyan@desy.de

2012-04-15

We study some properties of the non-Abelian vacuum induced by strong external magnetic field. We perform calculations in the quenched SU(3) lattice gauge theory with tadpole-improved Luescher-Weisz action and chirally invariant lattice Dirac operator. The following results are obtained: The chiral symmetry breaking is enhanced by the magnetic field. The chiral condensate depends on the strength of the applied field as a power function with exponent {nu} = 1.6 {+-} 0.2. There is a paramagnetic polarization of the vacuum. The corresponding susceptibility and other magnetic properties are calculated and compared with the theoretical estimations. There are nonzero local fluctuations ofmore » the chirality and electromagnetic current, which grow with the magnetic field strength. These fluctuations can be a manifestation of the Chiral Magnetic Effect.« less

Spin-flavor structure of chiral-odd generalized parton distributions in the large- N c limit

DOE PAGES

Schweitzer, P.; Weiss, C.

2016-10-05

We study the spin-flavor structure of the nucleon's chiral-odd generalized parton distributions (transversity GPDs) in the large-N c limit of QCD. In contrast to the chiral-even case, only three combinations of the four chiral-odd GPDs are nonzero in the leading order of the 1/N c expansion: E-bar T = E T+2H-tilde T, H T, and E-tilde T. The degeneracy is explained by the absence of spin-orbit interactions correlating the transverse momentum transfer with the transverse quark spin. It can also be deduced from the natural N c scaling of the quark-nucleon helicity amplitudes associated with the GPDs. In the GPDmore » E-bar T the flavor-singlet component u+d is leading in the 1/N c expansion, while in H T and E-tilde T it is the flavor-nonsinglet components u–d. Furthermore, the large-N c relations are consistent with the spin-flavor structure extracted from hard exclusive π 0 and η electroproduction data, if it is assumed that the processes are mediated by twist-3 amplitudes involving the chiral-odd GPDs and the chiral-odd pseudoscalar meson distribution amplitudes.« less

Meson properties at finite temperature in a three flavor nonlocal chiral quark model with Polyakov loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Contrera, G. A.; CONICET, Rivadavia 1917, 1033 Buenos Aires; Dumm, D. Gomez

2010-03-01

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles and decay constants. The critical temperature is found to be T{sub c{approx_equal}}202 MeV, in better agreement with lattice results than the value recently obtained in the local SU(3) PNJL model. Itmore » is seen that above T{sub c} pseudoscalar meson masses get increased, becoming degenerate with the masses of their chiral partners. The temperatures at which this matching occurs depend on the strange quark composition of the corresponding mesons. The topological susceptibility shows a sharp decrease after the chiral transition, signalling the vanishing of the U(1){sub A} anomaly for large temperatures.« less

Chiral dynamics with (non)strange quarks

NASA Astrophysics Data System (ADS)

Kubis, Bastian; Meißner, Ulf-G.

2017-01-01

We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405), the dynamical generation of the lowest S11 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy-Steiner analysis of pion-nucleon scattering, a high-precision extraction of the elusive pion-nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.

Precision Light Flavor Physics from Lattice QCD

NASA Astrophysics Data System (ADS)

Murphy, David

In this thesis we present three distinct contributions to the study of light flavor physics using the techniques of lattice QCD. These results are arranged into four self-contained papers. The first two papers concern global fits of the quark mass, lattice spacing, and finite volume dependence of the pseudoscalar meson masses and decay constants, computed in a series of lattice QCD simulations, to partially quenched SU(2) and SU(3) chiral perturbation theory (chiPT). These fits determine a subset of the low energy constants of chiral perturbation theory -- in some cases with increased precision, and in other cases for the first time -- which, once determined, can be used to compute other observables and amplitudes in chiPT. We also use our formalism to self-consistently probe the behavior of the (asymptotic) chiral expansion as a function of the quark masses by repeating the fits with different subsets of the data. The third paper concerns the first lattice QCD calculation of the semileptonic K0 → pi-l +nul ( Kl3) form factor at vanishing momentum transfer, f+Kpi(0), with physical mass domain wall quarks. The value of this form factor can be combined with a Standard Model analysis of the experimentally measured K0 → pi -l+nu l decay rate to extract a precise value of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus, and to test unitarity of the CKM matrix. We also discuss lattice calculations of the pion and kaon decay constants, which can be used to extract Vud through an analogous Standard Model analysis of experimental constraints on leptonic pion and kaon decays. The final paper explores the recently proposed exact one flavor algorithm (EOFA). This algorithm has been shown to drastically reduce the memory footprint required to simulate single quark flavors on the lattice relative to the widely used rational hybrid Monte Carlo (RHMC) algorithm, while also offering modest O(20%) speed-ups. We independently derive the exact one flavor action, explore its

Chiral U(1) flavor models and flavored Higgs doublets: the top FB asymmetry and the W jj

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ko, P.; Omura, Yuji; Yu, Chaehyun

2012-01-01

We present U(1) flavor models for leptophobic Z' with flavor dependent couplings to the right-handed up-type quarks in the Standard Model (SM), which can accommodate the recent data on the top forward-backward (FB) asymmetry and the dijet resonance associated with a W boson reported by CDF Collaboration. Such flavor-dependent leptophobic charge assignments generally require extra chiral fermions for anomaly cancellation. Also the chiral nature of U(1)' flavor symmetry calls for new U(1)'-charged Higgs doublets in order for the SM fermions to have realistic renormalizable Yukawa couplings. The stringent constraints from the top FB asymmetry at the Tevatron and the samemore » sign top pair production at the LHC can be evaded due to contributions of the extra Higgs doublets. We also show that the extension could realize cold dark matter candidates.« less

2+1 flavor lattice QCD toward the physical point

NASA Astrophysics Data System (ADS)

Aoki, S.; Ishikawa, K.-I.; Ishizuka, N.; Izubuchi, T.; Kadoh, D.; Kanaya, K.; Kuramashi, Y.; Namekawa, Y.; Okawa, M.; Taniguchi, Y.; Ukawa, A.; Ukita, N.; Yoshié, T.

2009-02-01

We present the first results of the PACS-CS project which aims to simulate 2+1 flavor lattice QCD on the physical point with the nonperturbatively O(a)-improved Wilson quark action and the Iwasaki gauge action. Numerical simulations are carried out at β=1.9, corresponding to the lattice spacing of a=0.0907(13)fm, on a 323×64 lattice with the use of the domain-decomposed HMC algorithm to reduce the up-down quark mass. Further algorithmic improvements make possible the simulation whose up-down quark mass is as light as the physical value. The resulting pseudoscalar meson masses range from 702 MeV down to 156 MeV, which clearly exhibit the presence of chiral logarithms. An analysis of the pseudoscalar meson sector with SU(3) chiral perturbation theory reveals that the next-to-leading order corrections are large at the physical strange quark mass. In order to estimate the physical up-down quark mass, we employ the SU(2) chiral analysis expanding the strange quark contributions analytically around the physical strange quark mass. The SU(2) low energy constants lmacr 3 and lmacr 4 are comparable with the recent estimates by other lattice QCD calculations. We determine the physical point together with the lattice spacing employing mπ, mK and mΩ as input. The hadron spectrum extrapolated to the physical point shows an agreement with the experimental values at a few % level of statistical errors, albeit there remain possible cutoff effects. We also find that our results of fπ, fK and their ratio, where renormalization is carries out perturbatively at one loop, are compatible with the experimental values. For the physical quark masses we obtain mudM Smacr and msM Smacr extracted from the axial-vector Ward-Takahashi identity with the perturbative renormalization factors. We also briefly discuss the results for the static quark potential.

Neutrinoless double beta decay and chiral SU(3)

DOE PAGES

Cirigliano, Vincenzo; Dekens, Wouter Gerard; Graesser, Michael Lawrence; ...

2017-04-14

TeV-scale lepton number violation can affect neutrinoless double beta decay through dimension-9 ΔL=ΔI=2 operators involving two electrons and four quarks. Since the dominant effects within a nucleus are expected to arise from pion exchange, the π -→π +ee matrix elements of the dimension-9 operators are a key hadronic input. Here in this letter we provide estimates for the π -→π + matrix elements of all Lorentz scalar ΔI=2 four-quark operators relevant to the study of TeV-scale lepton number violation. The analysis is based on chiral SU(3) symmetry, which relates the π -→π + matrix elements of the ΔI=2 operators to themore » $K$ 0→$$\\bar{K}$$ 0 and K→ππ matrix elements of their ΔS=2 and ΔS=1 chiral partners, for which lattice QCD input is available. The inclusion of next-to-leading order chiral loop corrections to all symmetry relations used in the analysis makes our results robust at the 30% level or better, depending on the operator.« less

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

NASA Astrophysics Data System (ADS)

Yao, De-Liang; Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A. M.; Gegelia, J.; Krebs, H.; Meißner, Ulf-G.

2016-05-01

We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.

Authenticity of raspberry flavor in food products using SPME-chiral-GC-MS.

PubMed

Hansen, Anne-Mette S; Frandsen, Henrik L; Fromberg, Arvid

2016-05-01

A fast and simple method for authenticating raspberry flavors from food products was developed. The two enantiomers of the compound (E)-α-ionone from raspberry flavor were separated on a chiral gas chromatographic column. Based on the ratio of these two enantiomers, the naturalness of a raspberry flavor can be evaluated due to the fact that a natural flavor will consist almost exclusively of the R enantiomer, while a chemical synthesis of the same compound will result in a racemic mixture. Twenty-seven food products containing raspberry flavors where investigated using SPME-chiral-GC-MS. We found raspberry jam, dried raspberries, and sodas declared to contain natural aroma all contained almost only R-(E)-α-ionone supporting the content of natural raspberry aroma. Six out of eight sweets tested did not indicate a content of natural aroma on the labeling which was in agreement with the almost equal distribution of the R and S isomer. Two products were labeled to contain natural raspberry flavors but were found to contain almost equal amounts of both enantiomers indicating a presence of synthetic raspberry flavors only. Additionally, two products that were labeled to contain both raspberry juice and flavor showed equal amounts of both enantiomers, indicating the presence of synthetic flavor.

Vector two-point functions in finite volume using partially quenched chiral perturbation theory at two loops

NASA Astrophysics Data System (ADS)

Bijnens, Johan; Relefors, Johan

2017-12-01

We calculate vector-vector correlation functions at two loops using partially quenched chiral perturbation theory including finite volume effects and twisted boundary conditions. We present expressions for the flavor neutral cases and the flavor charged case with equal masses. Using these expressions we give an estimate for the ratio of disconnected to connected contributions for the strange part of the electromagnetic current. We give numerical examples for the effects of partial quenching, finite volume and twisting and suggest the use of different twists to check the size of finite volume effects. The main use of this work is expected to be for lattice QCD calculations of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment.

d∗(2380) Resonance in a Chiral SU(3) Constituent Quark Model

NASA Astrophysics Data System (ADS)

Dong, Yubing; Shen, Pengnian; Huang, Fei; Zhang, Zongye

Recent studies on the newly observed resonance d∗(2380)(I(JP) = 0(3+)) with a compact structure in a chiral SU(3) constituent quark model are briefly reported. the overall properties, including the mass, the partial decay widths in various decay modes, and the total width, comparing with the experimental data, show that a compact hexaquark dominated structure might be a reasonable interpretation for this state. Moreover, the charge distribution of d∗ is also discussed.

Hadronic Lorentz violation in chiral perturbation theory including the coupling to external fields

NASA Astrophysics Data System (ADS)

Kamand, Rasha; Altschul, Brett; Schindler, Matthias R.

2018-05-01

If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a 2-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons—such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories—can only reliably constrain certain particular combinations of quark coefficients.

Individual eigenvalue distributions of crossover chiral random matrices and low-energy constants of SU(2) × U(1) lattice gauge theory

NASA Astrophysics Data System (ADS)

Yamamoto, Takuya; Nishigaki, Shinsuke M.

2018-02-01

We compute individual distributions of low-lying eigenvalues of a chiral random matrix ensemble interpolating symplectic and unitary symmetry classes by the Nyström-type method of evaluating the Fredholm Pfaffian and resolvents of the quaternion kernel. The one-parameter family of these distributions is shown to fit excellently the Dirac spectra of SU(2) lattice gauge theory with a constant U(1) background or dynamically fluctuating U(1) gauge field, which weakly breaks the pseudoreality of the unperturbed SU(2) Dirac operator. The observed linear dependence of the crossover parameter with the strength of the U(1) perturbations leads to precise determination of the pseudo-scalar decay constant, as well as the chiral condensate in the effective chiral Lagrangian of the AI class.

Kaon B-parameter in mixed action chiral perturbation theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubin, C.; Laiho, Jack; Water, Ruth S. van de

2007-02-01

We calculate the kaon B-parameter, B{sub K}, in chiral perturbation theory for a partially quenched, mixed-action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We find that the resulting expression is similar to that in the continuum, and in fact has only two additional unknown parameters. At 1-loop order, taste-symmetry violations in the staggered sea sector only contribute to flavor-disconnected diagrams by generating an O(a{sup 2}) shift to the masses of taste-singlet sea-sea mesons. Lattice discretization errors also give rise to an analytic term which shifts the tree-level value of B{sub K} by an amount of O(a{sup 2}). Thismore » term, however, is not strictly due to taste breaking, and is therefore also present in the expression for B{sub K} for pure Ginsparg-Wilson lattice fermions. We also present a numerical study of the mixed B{sub K} expression in order to demonstrate that both discretization errors and finite volume effects are small and under control on the MILC improved staggered lattices.« less

Chiral matrix model of the semi-QGP in QCD

DOE PAGES

Pisarski, Robert D.; Skokov, Vladimir V.

2016-08-08

Previously, a matrix model of the region near the transition temperature, in the “semi”quark gluon plasma, was developed for the theory of SU(3) gluons without quarks. In this paper we develop a chiral matrix model applicable to QCD by including dynamical quarks with 2+1 flavors. This requires adding a nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y. Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. As is standard, the potential for the scalar fields is chosen to bemore » symmetric under the flavor symmetry of SU (3) L × SU(3) R × Z (3) A , except for a term linear in the current quark mass, m qk . In addition, at a nonzero temperature T it is necessary to add a new term, ~ m qk T 2 . The parameters of the gluon part of the matrix model are identical to those for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant and the masses of the pions, kaons, η , and η' . The temperature for the chiral crossover at T$χ$ = 155 MeV is determined by adjusting the Yukawa coupling y . We find reasonable agreement with the results of numerical simulations on the lattice for the pressure and related quantities. In the chiral limit, besides the divergence in the chiral susceptibility there is also a milder divergence in the susceptibility between the Polyakov loop and the chiral order parameter, with critical exponent β $-$ 1 . We compute derivatives with respect to a quark chemical potential to determine the susceptibilities for baryon number, the $χ$ 2n . Especially sensitive tests are provided by $χ$ 4 $-$ $χ$ 2 and by $χ$ 6 , which changes in sign about T$χ$ . In conclusion, the behavior of the susceptibilities in the chiral matrix model strongly suggests that as the temperature increases from T$χ$ , that the transition to

Investigating the quark flavor dependence of the chiral magnetic effect with a multiphase transport model

NASA Astrophysics Data System (ADS)

Huang, Ling; Ma, Chun-Wang; Ma, Guo-Liang

2018-03-01

Because the properties of the QCD phase transition and the chiral magnetic effect (CME) depend on the number of quark flavors (Nf) and quark mass, relativistic heavy-ion collisions provide a natural environment to investigate the flavor features if quark deconfinement occurs. We introduce an initial two-flavor or three-flavor dipole charge separation into a multiphase transport (AMPT) model to investigate the flavor dependence of the CME. By taking advantage of the recent ALICE data of charge azimuthal correlations with identified hadrons, we attempt to disentangle two-flavor and three-flavor CME scenarios in Pb+Pb collisions at 2.76 TeV. We find that the experimental data show a certain potential to distinguish the two scenarios, therefore we further suggest to collect more data to clarify the possible flavor dependence in future experiments.

Chiral phase structure of three flavor QCD at vanishing baryon number density

DOE PAGES

Bazavov, A.; Ding, H. -T.; Hegde, P.; ...

2017-04-12

In this paper, we investigate the phase structure of QCD with three degenerate quark flavors as a function of the degenerate quark masses at vanishing baryon number density. We use the highly improved staggered quarks on lattices with temporal extent N τ = 6 and perform calculations for six values of quark masses, which in the continuum limit correspond to pion masses in the range 80 MeV ≲ m π ≲ 230 MeV. By analyzing the volume and temperature dependence of the chiral condensate and chiral susceptibility, we find no direct evidence for a first-order phase transition in this rangemore » of pion mass values. Finally, relying on the universal scaling behaviors of the chiral observables near an anticipated chiral critical point, we estimate an upper bound for the critical pion mass m c π ≲ 50 MeV, below which a region of first-order chiral phase transition is favored.« less

Lattice QCD at the physical point meets S U (2 ) chiral perturbation theory

NASA Astrophysics Data System (ADS)

Dürr, Stephan; Fodor, Zoltán; Hoelbling, Christian; Krieg, Stefan; Kurth, Thorsten; Lellouch, Laurent; Lippert, Thomas; Malak, Rehan; Métivet, Thibaut; Portelli, Antonin; Sastre, Alfonso; Szabó, Kálmán; Budapest-Marseille-Wuppertal Collaboration

2014-12-01

We perform a detailed, fully correlated study of the chiral behavior of the pion mass and decay constant, based on 2 +1 flavor lattice QCD simulations. These calculations are implemented using tree-level, O (a )-improved Wilson fermions, at four values of the lattice spacing down to 0.054 fm and all the way down to below the physical value of the pion mass. They allow a sharp comparison with the predictions of S U (2 ) chiral perturbation theory (χ PT ) and a determination of some of its low energy constants. In particular, we systematically explore the range of applicability of next-to-leading order (NLO) S U (2 ) χ PT in two different expansions: the first in quark mass (x expansion), and the second in pion mass (ξ expansion). We find that these expansions begin showing signs of failure for Mπ≳300 MeV , for the typical percent-level precision of our Nf=2 +1 lattice results. We further determine the LO low energy constants (LECs), F =88.0 ±1.3 ±0.2 and BMS ¯(2 GeV )=2.61 (6 )(1 ) GeV , and the related quark condensate, ΣMS ¯(2 GeV )=(272 ±4 ±1 MeV )3 , as well as the NLO ones, ℓ¯3=2.6 (5 )(3 ) and ℓ¯4=3.7 (4 )(2 ), with fully controlled uncertainties. We also explore the next-to-next-to-leading order (NNLO) expansions and the values of NNLO LECs. In addition, we show that the lattice results favor the presence of chiral logarithms. We further demonstrate how the absence of lattice results with pion masses below 200 MeV can lead to misleading results and conclusions. Our calculations allow a fully controlled, ab initio determination of the pion decay constant with a total 1% error, which is in excellent agreement with experiment.

Chiral phase transition of three flavor QCD with nonzero magnetic field using standard staggered fermions

NASA Astrophysics Data System (ADS)

Tomiya, Akio; Ding, Heng-Tong; Mukherjee, Swagato; Schmidt, Christian; Wang, Xiao-Dan

2018-03-01

Lattice simulations for (2+1)-flavor QCD with external magnetic field demon-strated that the quark mass is one of the important parameters responsible for the (inverse) magnetic catalysis. We discuss the dependences of chiral condensates and susceptibilities, the Polyakov loop on the magnetic field and quark mass in three degenerate flavor QCD. The lattice simulations are performed using standard staggered fermions and the plaquette action with spatial sizes Nσ = 16 and 24 and a fixed temporal size Nτ = 4. The value of the quark masses are chosen such that the system undergoes a first order chiral phase transition and crossover with zero magnetic field. We find that in light mass regime, the quark chiral condensate undergoes magnetic catalysis in the whole temperature region and the phase transition tend to become stronger as the magnetic field increases. In crossover regime, deconfinement transition temperature is shifted by the magnetic field when quark mass ma is less than 0:4. The lattice cutoff effects are also discussed.

Convergence properties of η → 3π decays in chiral perturbation theory

NASA Astrophysics Data System (ADS)

Kolesár, Marián; Novotný, Jiří

2017-01-01

The convergence of the decay widths and some of the Dalitz plot parameters of the decay η → 3π seems problematic in low energy QCD. In the framework of resummed chiral perturbation theory, we explore the question of compatibility of experimental data with a reasonable convergence of a carefully defined chiral series. By treating the uncertainties in the higher orders statistically, we numerically generate a large set of theoretical predictions, which are then confronted with experimental information. In the case of the decay widths, the experimental values can be reconstructed for a reasonable range of the free parameters and thus no tension is observed, in spite of what some of the traditional calculations suggest. The Dalitz plot parameters a and d can be described very well too. When the parameters b and α are concerned, we find a mild tension for the whole range of the free parameters, at less than 2σ C.L. This can be interpreted in two ways - either some of the higher order corrections are indeed unexpectedly large or there is a specific configuration of the remainders, which is, however, not completely improbable.

Near-threshold NN→dπ reaction in chiral perturbation theory

NASA Astrophysics Data System (ADS)

Gårdestig, A.; Phillips, D. R.; Elster, Ch.

2006-02-01

The near-threshold np→dπ0 cross section is calculated in chiral perturbation theory to next-to-leading order in the expansion parameter √(Mmπ)/Λχ. At this order irreducible pion loops contribute to the relevant pion-production operator. Although their contribution to this operator is finite, considering initial- and final-state distortions produces a linear divergence in its matrix elements. We renormalize this divergence by introducing a counterterm, whose value we choose to reproduce the threshold np→dπ0 cross section measured at TRIUMF. The energy dependence of this cross section is then predicted in chiral perturbation theory, being determined by the production of p-wave pions, and also by energy dependence in the amplitude for the production of s-wave pions. With an appropriate choice of the counterterm, the chiral prediction for this energy dependence converges well.

Broken chiral symmetry on a null plane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beane, Silas R., E-mail: silas@physics.unh.edu

2013-10-15

On a null-plane (light-front), all effects of spontaneous chiral symmetry breaking are contained in the three Hamiltonians (dynamical Poincaré generators), while the vacuum state is a chiral invariant. This property is used to give a general proof of Goldstone’s theorem on a null-plane. Focusing on null-plane QCD with N degenerate flavors of light quarks, the chiral-symmetry breaking Hamiltonians are obtained, and the role of vacuum condensates is clarified. In particular, the null-plane Gell-Mann–Oakes–Renner formula is derived, and a general prescription is given for mapping all chiral-symmetry breaking QCD condensates to chiral-symmetry conserving null-plane QCD condensates. The utility of the null-planemore » description lies in the operator algebra that mixes the null-plane Hamiltonians and the chiral symmetry charges. It is demonstrated that in a certain non-trivial limit, the null-plane operator algebra reduces to the symmetry group SU(2N) of the constituent quark model. -- Highlights: •A proof (the first) of Goldstone’s theorem on a null-plane is given. •The puzzle of chiral-symmetry breaking condensates on a null-plane is solved. •The emergence of spin-flavor symmetries in null-plane QCD is demonstrated.« less

Two-flavor simulations of ρ ( 770 ) and the role of the K K ¯ channel

DOE PAGES

Hu, B.; Molina, R.; Döring, M.; ...

2016-09-15

Here, the ρ(770) meson is the most extensively studied resonance in lattice QCD simulations in two (N f = 2) and three (N f = 2 + 1) flavor formulations. We analyze N f = 2 lattice scattering data using unitarized chiral perturbation theory, allowing not only for the extrapolation in mass but also in flavor, N f = 2 → N f = 2 + 1. The flavor extrapolation requires information from a global fit to ππ and πK phase shifts from experiment. While the chiral extrapolation of N f = 2 lattice data leads to masses of themore » ρ(770) meson far below the experimental one, we find that the missing KK¯ channel is able to explain this discrepancy.« less

The Kaon B-parameter in mixed action chiral perturbation theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubin, C.; /Columbia U.; Laiho, Jack

2006-09-01

We calculate the kaon B-parameter, B{sub K}, in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We find that the resulting expression is similar to that in the continuum, and in fact has only two additional unknown parameters. At one-loop order, taste-symmetry violations in the staggered sea sector only contribute to flavor-disconnected diagrams by generating an {Omicron}(a{sup 2}) shift to the masses of taste-singlet sea-sea mesons. Lattice discretization errors also give rise to an analytic term which shifts the tree-level value of B{sub K} by an amount of {Omicron}(a{sup 2}).more » This term, however, is not strictly due to taste-breaking, and is therefore also present in the expression for B{sub K} for pure G-W lattice fermions. We also present a numerical study of the mixed B{sub K} expression in order to demonstrate that both discretization errors and finite volume effects are small and under control on the MILC improved staggered lattices.« less

Scale-setting, flavor dependence, and chiral symmetry restoration

DOE PAGES

Binosi, D; Roberts, Craig D.; Rodriguez-Quintero, J.

2017-06-13

Here, we determine the flavor dependence of the renormalization-group-invariant running interaction through judicious use of both unquenched Dyson-Schwinger equation and lattice results for QCD’s gauge-sector two-point functions. An important step is the introduction of a physical scale setting procedure that enables a realistic expression of the effect of different numbers of active quark flavours on the interaction. Using this running interaction in concert with a well constrained class of dressed–gluon-quark vertices, we estimate the critical number of active lighter-quarks above which dynamical chiral symmetry breaking becomes impossible: n cr f ≈ 9; and hence in whose neighborhood QCD is plausiblymore » a conformal theory.« less

Towards gauge coupling unification in left-right symmetric SU (3 )c×SU (3 )L×SU (3 )R×U (1 )X theories

NASA Astrophysics Data System (ADS)

Hati, Chandan; Patra, Sudhanwa; Reig, Mario; Valle, José W. F.; Vaquera-Araujo, C. A.

2017-07-01

We consider the possibility of gauge coupling unification within the simplest realizations of the SU (3 )c×SU (3 )L×SU (3 )R×U (1 )X gauge theory. We present a first exploration of the renormalization group equations governing the "bottom-up" evolution of the gauge couplings in a generic model with free normalization for the generators. Interestingly, we find that for a SU (3 )c×SU (3 )L×SU (3 )R×U (1 )X symmetry breaking scale MX as low as a few TeV one can achieve unification in the presence of leptonic octets. We briefly comment on possible grand unified theory frameworks which can embed the SU (3 )c×SU (3 )L×SU (3 )R×U (1 )X model as well as possible implications, such as lepton flavor violating physics at the LHC.

The Chiral and Angular Momentum Content of the ρ-Meson

NASA Astrophysics Data System (ADS)

Glozman, L. Ya.; Lang, C. B.; Limmer, M.

2010-01-01

It is possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark Fock component of a meson in the infrared, where mass is generated. Using the variational method and a set of interpolators that span a complete chiral basis we extract in a lattice QCD Monte Carlo simulation with n f = 2 dynamical light quarks the orbital angular momentum and spin content of the ρ-meson. We obtain in the infrared a simple 3 S 1 component as a leading component of the ρ-meson with a small admixture of the 3 D 1 partial wave, in agreement with the SU(6) flavor-spin symmetry.

Low energy constants of S U ( 2 ) partially quenched chiral perturbation theory from N f = 2 + 1 domain wall QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyle, P. A.; Christ, N. H.; Garron, N.

2016-03-09

Here, we have performed fits of the pseudoscalar masses and decay constants, from a variety of the RBC-UKQCD Collaboration’s domain wall fermion ensembles, to SU(2) partially quenched chiral perturbation theory at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). We report values for 9 NLO and 8 linearly independent combinations of NNLO partially quenched low-energy constants, which we compare to other lattice and phenomenological determinations. We discuss the size of successive terms in the chiral expansion and use our large set of low-energy constants to make predictions for mass splittings due to QCD isospin-breaking effects and the S-wave ππ scattering lengths.more » Lastly, we conclude that, for the range of pseudoscalar masses explored in this work, 115 MeV≲mPS≲430 MeV, the NNLO SU(2) expansion is quite robust and can fit lattice data with percent-scale accuracy.« less

Matching Pion-Nucleon Roy-Steiner Equations to Chiral Perturbation Theory.

PubMed

Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meissner, Ulf-G

2015-11-06

We match the results for the subthreshold parameters of pion-nucleon scattering obtained from a solution of Roy-Steiner equations to chiral perturbation theory up to next-to-next-to-next-to-leading order, to extract the pertinent low-energy constants including a comprehensive analysis of systematic uncertainties and correlations. We study the convergence of the chiral series by investigating the chiral expansion of threshold parameters up to the same order and discuss the role of the Δ(1232) resonance in this context. Results for the low-energy constants are also presented in the counting scheme usually applied in chiral nuclear effective field theory, where they serve as crucial input to determine the long-range part of the nucleon-nucleon potential as well as three-nucleon forces.

Matching Pion-Nucleon Roy-Steiner Equations to Chiral Perturbation Theory

NASA Astrophysics Data System (ADS)

Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.

2015-11-01

We match the results for the subthreshold parameters of pion-nucleon scattering obtained from a solution of Roy-Steiner equations to chiral perturbation theory up to next-to-next-to-next-to-leading order, to extract the pertinent low-energy constants including a comprehensive analysis of systematic uncertainties and correlations. We study the convergence of the chiral series by investigating the chiral expansion of threshold parameters up to the same order and discuss the role of the Δ (1232 ) resonance in this context. Results for the low-energy constants are also presented in the counting scheme usually applied in chiral nuclear effective field theory, where they serve as crucial input to determine the long-range part of the nucleon-nucleon potential as well as three-nucleon forces.

B- and D-meson decay constants from three-flavor lattice QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bazavov, A.; et al.

2012-06-01

We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavy-light meson correlation functions on the MILC asqtad-improved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence- and sea-quark masses (down to ~m_s/10) and at three lattice spacings (a ~ 0.15, 0.12, and 0.09 fm) and extrapolate to the physical up and down quark masses and the continuum using expressions derived in heavy-light meson staggered chiral perturbation theory. We renormalizemore » the heavy-light axial current using a mostly nonperturbative method such that only a small correction to unity must be computed in lattice perturbation theory and higher-order terms are expected to be small. We obtain f_{B^+} = 196.9(8.9) MeV, f_{B_s} = 242.0(9.5) MeV, f_{D^+} = 218.9(11.3) MeV, f_{D_s} = 260.1(10.8) MeV, and the SU(3) flavor-breaking ratios f_{B_s}/f_{B} = 1.229(26) and f_{D_s}/f_{D} = 1.188(25), where the numbers in parentheses are the total statistical and systematic uncertainties added in quadrature.« less

On the chiral magnetic effect in Weyl superfluid 3He-A

NASA Astrophysics Data System (ADS)

Volovik, G. E.

2017-01-01

In the theory of the chiral anomaly in relativistic quantum field theories (RQFTs), some results depend on a regularization scheme at ultraviolet. In the chiral superfluid 3He-A, which contains two Weyl points and also experiences the effects of chiral anomaly, the "trans-Planckian" physics is known and the results can be obtained without regularization. We discuss this on example of the chiral magnetic effect (CME), which has been observed in 3He-A in the 1990s [1]. There are two forms of the contribution of the CME to the Chern-Simons term in free energy, perturbative and non-perturbative. The perturbative term comes from the fermions living in the vicinity of the Weyl point, where the fermions are "relativistic" and obey the Weyl equation. The non-perturbative term originates from the deep vacuum, being determined by the separation of the two Weyl points in momentum space. Both terms are obtained using the Adler-Bell-Jackiw equation for chiral anomaly, and both agree with the results of the microscopic calculations in the "trans-Planckian" region. Existence of the two nonequivalent forms of the Chern-Simons term demonstrates that the results obtained within the RQFT depend on the specific properties of the underlying quantum vacuum and may reflect different physical phenomena in the same vacuum.

Anomaly constraints on deconfinement and chiral phase transition

NASA Astrophysics Data System (ADS)

Shimizu, Hiroyuki; Yonekura, Kazuya

2018-05-01

We study the constraints on thermal phase transitions of SU (Nc) gauge theories by using the 't Hooft anomaly involving the center symmetry and chiral symmetry. We consider two cases of massless fermions: (i) adjoint fermions and (ii) Nf flavors of fundamental fermions with a nontrivial greatest common divisor, gcd (Nc,Nf)≠1 . For the first case (i), we show that the chiral symmetry restoration in terms of the standard Landau-Ginzburg effective action is impossible at a temperature lower than that of deconfinement. For the second case (ii), we introduce a modified version of the center symmetry, which we call center-flavor symmetry, and draw similar conclusions under a certain definition of confinement. Moreover, at zero temperature, our results give a partial explanation of the appearance of dual magnetic gauge groups in (supersymmetric) QCD when gcd (Nc,Nf)≠1 .

Spin-Flavor van der Waals Forces and NN interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alvaro Calle Cordon, Enrique Ruiz Arriola

A major goal in Nuclear Physics is the derivation of the Nucleon-Nucleon (NN) interaction from Quantum Chromodynamics (QCD). In QCD the fundamental degrees of freedom are colored quarks and gluons which are confined to form colorless strongly interacting hadrons. Because of this the resulting nuclear forces at sufficiently large distances correspond to spin-flavor excitations, very much like the dipole excitations generating the van der Waals (vdW) forces acting between atoms. We study the Nucleon-Nucleon interaction in the Born-Oppenheimer approximation at second order in perturbation theory including the Delta resonance as an intermediate state. The potential resembles strongly chiral potentials computedmore » either via soliton models or chiral perturbation theory and has a van der Waals like singularity at short distances which is handled by means of renormalization techniques. Results for the deuteron are discussed.« less

Nucleon-nucleon scattering parameters in the limit of SU(3) flavor symmetry

NASA Astrophysics Data System (ADS)

Beane, S. R.; Chang, E.; Cohen, S. D.; Detmold, W.; Junnarkar, P.; Lin, H. W.; Luu, T. C.; Orginos, K.; Parreño, A.; Savage, M. J.; Walker-Loud, A.

2013-08-01

The scattering lengths and effective ranges that describe low-energy nucleon-nucleon scattering are calculated in the limit of SU(3)-flavor symmetry at the physical strange-quark mass with lattice quantum chromodynamics. The calculations are performed with an isotropic clover discretization of the quark action in three volumes with spatial extents of L˜3.4fm, 4.5fm, and 6.7fm, and with a lattice spacing of b˜0.145fm. With determinations of the energies of the two-nucleon systems (both of which contain bound states at these up and down quark masses) at rest and moving in the lattice volume, Lüscher's method is used to determine the low-energy phase shifts in each channel, from which the scattering length and effective range are obtained. The scattering parameters, in the 1S0 channel are found to be mπa(1S0)=9.50-0.69+0.78-0.80+1.10 and mπr(1S0)=4.61-0.31+0.29-0.26+0.24, and in the 3S1 channel are mπa(3S1)=7.45-0.53+0.57-0.49+0.71 and mπr(3S1)=3.71-0.31+0.28-0.35+0.28. These values are consistent with the two-nucleon system exhibiting Wigner's supermultiplet symmetry, which becomes exact in the limit of large Nc. In both spin channels, the phase shifts change sign at higher momentum, near the start of the t-channel cut, indicating that the nuclear interactions have a repulsive core even at the SU(3)-symmetric point.

Charmed baryon weak decays with SU(3) flavor symmetry

NASA Astrophysics Data System (ADS)

Geng, C. Q.; Hsiao, Y. K.; Liu, Chia-Wei; Tsai, Tien-Hsueh

2017-11-01

We study the semileptonic and non-leptonic charmed baryon decays with SU(3) flavor symmetry, where the charmed baryons can be B c = (Ξ c 0 , Ξ c + , Λ c + ), B c ' = ( Σ c (++,+,0) , Ξ c ' (+,0) , Ω c 0 ), B cc = (Ξ cc + + , Ξ cc + , Ω c + ) or B cc = Ω ccc + + . With B n (') denoted as the baryon octet (decuplet), we find that the B c → B n ' ℓ + ν ℓ decays are forbidden, while the Ω c 0 → Ω- ℓ + ν ℓ , Ω cc + → Ω c 0 ℓ + ν ℓ , and Ω ccc + + → Ω cc + ℓ + ν ℓ decays are the only existing Cabibbo- allowed modes for B c ' → B n ' ℓ + ν ℓ , B cc → B c ' ℓ + ν ℓ , and B ccc → B cc (') ℓ + ν ℓ , respectively. We predict the rarely studied B c → B n (') M decays, such as B({Ξ}_c^0\\to {Λ}^0{\\overline{K}}^0,{Ξ}_c+\\to {Ξ}^0{π}+)=(8.3± 0.9, 8.0± 4.1)× {10}^{-3} and B({Λ}_c+\\to {Δ}^{++}{π}-,{Ξ}_c^0\\to {Ω}-{K}+)=(5.5± 1.3, 4.8± 0.5)× {10}^{-3} . For the observation, the doubly and triply charmed baryon decays of {Ω}_{cc}+\\to {Ξ}_c+{\\overline{K}}^0,{Ξ}_{cc}^{++}\\to ({Ξ}_c+{π}+,{Σ}_c^{++}{\\overline{K}}^0), and {Ω}_{ccc}^{++}\\to ({Ξ}_{cc}^{++}{\\overline{K}}^0,{Ω}_{cc}+{π}+,{Ξ}_c+{D}+) are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.

SIMP model at NNLO in chiral perturbation theory

NASA Astrophysics Data System (ADS)

Hansen, Martin; Langæble, Kasper; Sannino, Francesco

2015-10-01

We investigate the phenomenological viability of a recently proposed class of composite dark matter models where the relic density is determined by 3 →2 number-changing processes in the dark sector. Here the pions of the strongly interacting field theory constitute the dark matter particles. By performing a consistent next-to-leading- and next-to-next-to-leading-order chiral perturbative investigation we demonstrate that the leading-order analysis cannot be used to draw conclusions about the viability of the model. We further show that higher-order corrections substantially increase the tension with phenomenological constraints challenging the viability of the simplest realization of the strongly interacting massive particle paradigm.

Supersymmetric Gauge Theories with Decoupled Operators and Chiral Ring Stability

NASA Astrophysics Data System (ADS)

Benvenuti, Sergio; Giacomelli, Simone

2017-12-01

We propose a general way to complete supersymmetric theories with operators below the unitarity bound, adding gauge-singlet fields that enforce the decoupling of such operators. This makes it possible to perform all usual computations, and to compactify on a circle. We concentrate on a duality between an N =1 SU(2) gauge theory and the N =2 A3 Argyres-Douglas theory, mapping the moduli space and chiral ring of the completed N =1 theory to those of the A3 model. We reduce the completed gauge theory to 3D, finding a 3D duality with N =4 supersymmetric QED (SQED) with two flavors. The naive dimensional reduction is instead N =2 SQED. Crucial is a concept of chiral ring stability, which modifies the superpotential and allows for a 3D emergent global symmetry.

Flavor and chiral stability of lemon-flavored hard tea during storage.

PubMed

He, Fei; Qian, YanPing L; Qian, Michael C

2018-01-15

Flavor stability of hard tea beverage was investigated over eight weeks of storage. The volatile compounds were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and two-dimensional GC-MS. Quantitative analysis showed that the concentrations of linalool, citronellol, geranial, neral, geraniol, and nerol decreased dramatically during storage, whereas α-terpineol showed an increasing trend during storage. Heart-cut two-dimensional GC-MS (2D-GC-MS) chirality analysis showed that (R)-(+)-limonene, (R)-(-)-linalool, (S)-(-)-α-terpineol and (S)-(-)-4-terpineol dominated in the fresh hard tea samples, however, the configuration changed during storage for the terpene alcohols. The storage conditions did not change the configuration of limonene. A conversion of (R)-(-)-linalool to (S)-(+) form was observed during storage. Both (S)-α-terpineol and (S)-4-terpineol dominated at beginning of the storage, but (R)-(+)-α-terpineol became dominated after storage, suggested in addition to isomerization from (S)-α-terpineol, other precursors could also generate α-terpineol with (R)-isomer preference. Copyright © 2017 Elsevier Ltd. All rights reserved.

Baryon chiral perturbation theory extended beyond the low-energy region.

PubMed

Epelbaum, E; Gegelia, J; Meißner, Ulf-G; Yao, De-Liang

We consider an extension of the one-nucleon sector of baryon chiral perturbation theory beyond the low-energy region. The applicability of this approach for higher energies is restricted to small scattering angles, i.e. the kinematical region, where the quark structure of hadrons cannot be resolved. The main idea is to re-arrange the low-energy effective Lagrangian according to a new power counting and to exploit the freedom of the choice of the renormalization condition for loop diagrams. We generalize the extended on-mass-shell scheme for the one-nucleon sector of baryon chiral perturbation theory by choosing a sliding scale, that is, we expand the physical amplitudes around kinematical points beyond the threshold. This requires the introduction of complex-valued renormalized coupling constants, which can be either extracted from experimental data, or calculated using the renormalization group evolution of coupling constants fixed in threshold region.

SU(2) Flavor Asymmetry of the Proton Sea in Chiral Effective Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKenney, J. R.; Sato Gonzalez, Nobuo; Melnitchouk, Wally

We refine the computation of themore » $$\\bar{d}$$ - $$\\bar{u}$$ flavor asymmetry in the proton sea with a complementary effort to reveal the dynamics of pion exchange in high-energy processes. In particular, we discuss the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA along with the $$\\bar{d}$$ - $$\\bar{u}$$ flavor asymmetry in the proton. A detailed χ 2 analysis of the ZEUS and H1 data, when combined with constraints on the pion flux from Drell-Yan data, allows regions of applicability of one-pion exchange to be delineated. Based on the fit results, we also address a possible estimate for leading proton structure functions in upcoming tagged deep-inelastic scattering experiments at Jefferson Lab on the deuteron with forward protons.« less

Flavor unity in SU(7): Low-mass magnetic monopole, doubly charged lepton,and Q = 5/3,-4/3 quarks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J.E.

1981-06-01

A specific flavor unification is suggested in the SU(7) gauge group. This model can be trivially extended to O(14). A global symmetry GAMMA forbids mixings of the b (Q = -1/3) quark with the d and s quarks, and of the t (Q = 2/3) quark with the u and c quarks. Since the b and t quarks carry different GAMMA quantum numbers, they do not belong to the same SU(2)/sub L/ doublet. A mechanism for the GAMMA-symmetry violation is suggested, which allows c-t mixing without b-quark mixing. There are unconventionally charged light (masses < or approx. =300 GeV) fermions:more » a doubly charged lepton T/sup - -/, a Q = -4/3 quark x, and a Q = 5/3 quark y. The bare value of the Weinberg angle sin/sup 2/theta/sup 0//sub W/ = 3/20 is renormalized to the low-energy value by introducing an intermediate mass scale M/sub 1/. A topologically stable magnetic monopole is light (massroughly-equalM/sub 1//..cap alpha..) and hence there does not exist a conflict arising from the grand unified theories and the hot-big-bang cosmology.« less

QCD phase transition with chiral quarks and physical quark masses.

PubMed

Bhattacharya, Tanmoy; Buchoff, Michael I; Christ, Norman H; Ding, H-T; Gupta, Rajan; Jung, Chulwoo; Karsch, F; Lin, Zhongjie; Mawhinney, R D; McGlynn, Greg; Mukherjee, Swagato; Murphy, David; Petreczky, P; Renfrew, Dwight; Schroeder, Chris; Soltz, R A; Vranas, P M; Yin, Hantao

2014-08-22

We report on the first lattice calculation of the QCD phase transition using chiral fermions with physical quark masses. This calculation uses 2+1 quark flavors, spatial volumes between (4 fm)(3) and (11 fm)(3) and temperatures between 139 and 196 MeV. Each temperature is calculated at a single lattice spacing corresponding to a temporal Euclidean extent of N(t) = 8. The disconnected chiral susceptibility, χ(disc) shows a pronounced peak whose position and height depend sensitively on the quark mass. We find no metastability near the peak and a peak height which does not change when a 5 fm spatial extent is increased to 10 fm. Each result is strong evidence that the QCD "phase transition" is not first order but a continuous crossover for m(π) = 135 MeV. The peak location determines a pseudocritical temperature T(c) = 155(1)(8) MeV, in agreement with earlier staggered fermion results. However, the peak height is 50% greater than that suggested by previous staggered results. Chiral SU(2)(L) × SU(2)(R) symmetry is fully restored above 164 MeV, but anomalous U(1)(A) symmetry breaking is nonzero above T(c) and vanishes as T is increased to 196 MeV.

Quark chiral condensate from the overlap quark propagator

NASA Astrophysics Data System (ADS)

Wang, Chao; Bi, Yujiang; Cai, Hao; Chen, Ying; Gong, Ming; Liu, Zhaofeng

2017-05-01

From the overlap lattice quark propagator calculated in the Landau gauge, we determine the quark chiral condensate by fitting operator product expansion formulas to the lattice data. The quark propagators are computed on domain wall fermion configurations generated by the RBC-UKQCD Collaborations with N f = 2+1 flavors. Three ensembles with different light sea quark masses are used at one lattice spacing 1/a = 1.75(4) GeV. We obtain in the SU(2) chiral limit. Supported by National Natural Science Foundation of China (11575197, 11575196, 11335001, 11405178), joint funds of NSFC (U1632104, U1232109), YC and ZL acknowledge the support of NSFC and DFG (CRC110)

The eightfold way model, the SU(3)-flavor model and the medium-strong interaction

NASA Astrophysics Data System (ADS)

Abbas, Syed Afsar

2015-04-01

Lack of any baryon number in the eightfold way model, and its intrinsic presence in the SU(3)-flavor model, has been a puzzle since the genesis of these models in 1961-1964. First we show that the conventional popular understanding of this puzzle is actually fundamentally wrong, and hence the problem being so old, begs urgently for resolution. In this paper we show that the issue is linked to the way that the adjoint representation is defined mathematically for a Lie algebra, and how it manifests itself as a physical representation. This forces us to distinguish between the global and the local charges and between the microscopic and the macroscopic models. As a bonus, a consistent understanding of the hitherto mysterious medium-strong interaction is achieved. We also gain a new perspective on how confinement arises in quantum chromodynamics.

Bound H dibaryon in flavor SU(3) limit of lattice QCD.

PubMed

Inoue, Takashi; Ishii, Noriyoshi; Aoki, Sinya; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji

2011-04-22

The flavor-singlet H dibaryon, which has strangeness -2 and baryon number 2, is studied by the approach recently developed for the baryon-baryon interactions in lattice QCD. The flavor-singlet central potential is derived from the spatial and imaginary-time dependence of the Nambu-Bethe-Salpeter wave function measured in N(f)=3 full QCD simulations with the lattice size of L≃2,3,4  fm. The potential is found to be insensitive to the volume, and it leads to a bound H dibaryon with the binding energy of 30-40 MeV for the pseudoscalar meson mass of 673-1015 MeV.

Chiral perturbation theory and nucleon-pion-state contaminations in lattice QCD

NASA Astrophysics Data System (ADS)

Bär, Oliver

2017-05-01

Multiparticle states with additional pions are expected to be a non-negligible source of excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory can be employed to calculate the contamination due to two-particle nucleon-pion-states in various nucleon observables. Leading order results are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions (quark momentum fraction, helicity and transversity moment). Taking into account phenomenological results for the charges and moments the impact of the nucleon-pion-states on lattice estimates for these observables can be estimated. The nucleon-pion-state contribution results in an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5-10% level for source-sink separations of about 2 fm. The source-sink separations accessible in contemporary lattice simulations are found to be too small for chiral perturbation theory to be directly applicable.

Continuum limit of Bk from 2+1 flavor domain wall QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soni, A.; T. Izubuchi, et al.

2011-07-01

We determine the neutral kaon mixing matrix element B{sub K} in the continuum limit with 2+1 flavors of domain wall fermions, using the Iwasaki gauge action at two different lattice spacings. These lattice fermions have near exact chiral symmetry and therefore avoid artificial lattice operator mixing. We introduce a significant improvement to the conventional nonperturbative renormalization (NPR) method in which the bare matrix elements are renormalized nonperturbatively in the regularization invariant momentum scheme (RI-MOM) and are then converted into the MS{sup -} scheme using continuum perturbation theory. In addition to RI-MOM, we introduce and implement four nonexceptional intermediate momentum schemesmore » that suppress infrared nonperturbative uncertainties in the renormalization procedure. We compute the conversion factors relating the matrix elements in this family of regularization invariant symmetric momentum schemes (RI-SMOM) and MS{sup -} at one-loop order. Comparison of the results obtained using these different intermediate schemes allows for a more reliable estimate of the unknown higher-order contributions and hence for a correspondingly more robust estimate of the systematic error. We also apply a recently proposed approach in which twisted boundary conditions are used to control the Symanzik expansion for off-shell vertex functions leading to a better control of the renormalization in the continuum limit. We control chiral extrapolation errors by considering both the next-to-leading order SU(2) chiral effective theory, and an analytic mass expansion. We obtain B{sub K}{sup MS{sup -}} (3 GeV) = 0.529(5){sub stat}(15){sub {chi}}(2){sub FV}(11){sub NPR}. This corresponds to B{sup -}{sub K}{sup RGI{sup -}} = 0.749(7){sub stat}(21){sub {chi}}(3){sub FV}(15){sub NPR}. Adding all sources of error in quadrature, we obtain B{sup -}{sub K}{sup RGI{sup -}} = 0.749(27){sub combined}, with an overall combined error of 3.6%.« less

Triplets, Static SU(6), and Spontaneously Broken Chiral SU(3) Symmetry

DOE R&D Accomplishments Database

Nambu, Y.

1966-01-01

I would like to present here my view of the current problems of elementary particle theory. It is largely inspired by the recent successes of SU(3) and SU(6) symmetries, and more or less summarizes what I have been pursuing lately. For the details of individual problems I must refer to the original papers. However, what is emphasized here is not the details, but a coherent overall picture plus some speculations which cannot yet be formulated precisely.

Staggered chiral perturbation theory at next-to-leading order

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharpe, Stephen R.; Van de Water, Ruth S.

2005-06-01

We study taste and Euclidean rotational symmetry violation for staggered fermions at nonzero lattice spacing using staggered chiral perturbation theory. We extend the staggered chiral Lagrangian to O(a{sup 2}p{sup 2}), O(a{sup 4}), and O(a{sup 2}m), the orders necessary for a full next-to-leading order calculation of pseudo-Goldstone boson masses and decay constants including analytic terms. We then calculate a number of SO(4) taste-breaking quantities, which involve only a small subset of these next-to-leading order operators. We predict relationships between SO(4) taste-breaking splittings in masses, pseudoscalar decay constants, and dispersion relations. We also find predictions for a few quantities that are notmore » SO(4) breaking. All these results hold also for theories in which the fourth root of the fermionic determinant is taken to reduce the number of quark tastes; testing them will therefore provide evidence for or against the validity of this trick.« less

The SU(3)/Z3 QCD(adj) deconfinement transition via the gauge theory/"affine" XY-model duality

NASA Astrophysics Data System (ADS)

Anber, Mohamed M.; Collier, Scott; Poppitz, Erich

2013-01-01

Earlier, two of us and M. Ünsal [1] showed that a class of 4d gauge theories, when compactified on a small spatial circle of size L and considered at temperatures β-1 near the deconfinement transition, are dual to 2d "affine" XY-spin models. We exploit this duality to study the deconfinement phase transition in SU(3)/{{{Z}}_3} gauge theories with n f > 1 massless adjoint Weyl fermions, QCD(adj) on {{{R}}^2}× {S}_{β}^1× {S}_L^1 . The dual "affine" XY-model describes two "spins" — compact scalars taking values in the SU(3) root lattice. The spins couple via nearest-neighbor interactions and are subject to an "external field" perturbation preserving the topological {Z}_3^t and a discrete {Z}_3^{{{d_{\\upchi}}}} subgroup of the anomaly-free chiral symmetry of the 4d gauge theory. The equivalent Coulomb gas representation of the theory exhibits electric-magnetic duality, which is also a high-/low-temperature duality. A renormalization group analysis suggests — but is not convincing, due to the onset of strong coupling — that the self-dual point is a fixed point, implying a continuous deconfinement transition. Here, we study the nature of the transition via Monte Carlo simulations. The {Z}_3^t× {Z}_3^{{{d_{\\upchi}}}} order parameter, its susceptibility, the vortex density, the energy per spin, and the specific heat are measured over a range of volumes, temperatures, and "external field" strengths (in the gauge theory, these correspond to magnetic bion fugacities). The finite-size scaling of the susceptibility and specific heat we find is characteristic of a first-order transition. Furthermore, for sufficiently large but still smaller than unity bion fugacity (as can be achieved upon an increase of the {S}_L^1 size), at the critical temperature we find two distinct peaks of the energy probability distribution, indicative of a first-order transition, as has been seen in earlier simulations of the full 4d QCD(adj) theory. We end with discussions of the global

Finite volume effects in the chiral extrapolation of baryon masses

NASA Astrophysics Data System (ADS)

Lutz, M. F. M.; Bavontaweepanya, R.; Kobdaj, C.; Schwarz, K.

2014-09-01

We perform an analysis of the QCD lattice data on the baryon octet and decuplet masses based on the relativistic chiral Lagrangian. The baryon self-energies are computed in a finite volume at next-to-next-to-next-to-leading order (N3LO), where the dependence on the physical meson and baryon masses is kept. The number of free parameters is reduced significantly down to 12 by relying on large-Nc sum rules. Altogether we describe accurately more than 220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC, QCDSF-UKQCD and NPLQCD. Values for all counterterms relevant at N3LO are predicted. In particular we extract a pion-nucleon sigma term of 39-1+2 MeV and a strangeness sigma term of the nucleon of σsN=84-4+28 MeV. The flavor SU(3) chiral limit of the baryon octet and decuplet masses is determined with (802±4) and (1103±6) MeV. Detailed predictions for the baryon masses as currently evaluated by the ETM lattice QCD group are made.

Chiral magnetic effect in lattice QCD with a chiral chemical potential.

PubMed

Yamamoto, Arata

2011-07-15

We perform a first lattice QCD simulation including a two-flavor dynamical fermion with a chiral chemical potential. Because the chiral chemical potential gives rise to no sign problem, we can exactly analyze a chirally imbalanced QCD matter by Monte Carlo simulation. By applying an external magnetic field to this system, we obtain a finite induced current along the magnetic field, which corresponds to the chiral magnetic effect. The obtained induced current is proportional to the magnetic field and to the chiral chemical potential, which is consistent with an analytical prediction.

SU(3) sextet model with Wilson fermions

NASA Astrophysics Data System (ADS)

Hansen, Martin; Pica, Claudio

2018-03-01

We present our final results for the SU(3) sextet model with the non-improved Wilson fermion discretization. We find evidence for several phases of the lattice model, including a bulk phase with broken chiral symmetry. We study the transition between the bulk and weak coupling phase which corresponds to a significant change in the qualitative behavior of spectral and scale setting observables. In particular the t0 and w0 observables seem to diverge in the chiral limit in the weak coupling phase. We then focus on the study of spectral observables in the chiral limit in the weak coupling phase at infinite volume. We consider the masses and decay constants for the pseudoscalar and vector mesons, the mass of the axial vector meson and the spin-1/2 baryon as a function of the quark mass, while controlling finite volume effects. We then test our data against both the IR conformal and the chirally broken hypotheses. Preprint: CP3-Origins-2017-49 DNRF90

How tetraquarks can generate a second chiral phase transition

DOE PAGES

Pisarski, Robert D.; Skokov, Vladimir V.

2016-09-09

We consider how tetraquarks can affect the chiral phase transition in theories like QCD, with light quarks coupled to three colors. For two flavors the tetraquark field is an isosinglet, and its effect is minimal. For three flavors, however, the tetraquark field transforms in the same representation of the chiral symmetry group as the usual chiral order parameter, and so for very light quarks there may be two chiral phase transitions, which are both of first order. In QCD, results from the lattice indicate that any transition from the tetraquark condensate is a smooth crossover. In the plane of temperature,more » T, and quark chemical potential, μ, though, a crossover line for the tetraquark condensate is naturally related to the transition line for color superconductivity. For four flavors we suggest that a triquark field, antisymmetric in both flavor and color, combine to form hexaquarks.« less

Pair production processes and flavor in gauge-invariant perturbation theory

NASA Astrophysics Data System (ADS)

Egger, Larissa; Maas, Axel; Sondenheimer, René

2017-12-01

Gauge-invariant perturbation theory is an extension of ordinary perturbation theory which describes strictly gauge-invariant states in theories with a Brout-Englert-Higgs effect. Such gauge-invariant states are composite operators which have necessarily only global quantum numbers. As a consequence, flavor is exchanged for custodial quantum numbers in the Standard Model, recreating the fermion spectrum in the process. Here, we study the implications of such a description, possibly also for the generation structure of the Standard Model. In particular, this implies that scattering processes are essentially bound-state-bound-state interactions, and require a suitable description. We analyze the implications for the pair-production process e+e-→f¯f at a linear collider to leading order. We show how ordinary perturbation theory is recovered as the leading contribution. Using a PDF-type language, we also assess the impact of sub-leading contributions. To lowest order, we find that the result is mainly influenced by how large the contribution of the Higgs at large x is. This gives an interesting, possibly experimentally testable, scenario for the formal field theory underlying the electroweak sector of the Standard Model.

A Flavorful Factoring of the Strong CP Problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, Prateek; Howe, Kiel

Motivated by the intimate connection between the strong CP problem and the flavor structure of the Standard Model, we present a flavor model that revives and extends the classicmore » $${m_u=0}$$ solution to the strong CP problem. QCD is embedded into a $$SU(3)_1\\times SU(3)_2 \\times SU(3)_3$$ gauge group, with each generation of quarks charged under the respective $SU(3)$. The non-zero value of the up-quark Yukawa coupling (along with the strange quark and bottom-quark Yukawas) is generated by contributions from small instantons at a new scale $$M \\gg \\Lambda_{QCD}$$. The Higgsing of $$SU(3)^3\\to SU(3)_c$$ allows dimension-5 operators that generate the Standard Model flavor structure and can be completed in a simple renormalizable theory. The smallness of the third generation mixing angles can naturally emerge in this picture, and is connected to the smallness of threshold corrections to $$\\bar\\theta$$. Remarkably, $$\\bar\\theta$$ is essentially fixed by the measured quark masses and mixings, and is estimated to be close to the current experimental bound and well within reach of the next generation of neutron and proton EDM experiments.« less

Patterns of symmetry breaking in chiral QCD

NASA Astrophysics Data System (ADS)

Bolognesi, Stefano; Konishi, Kenichi; Shifman, Mikhail

2018-05-01

We consider S U (N ) Yang-Mills theory with massless chiral fermions in a complex representation of the gauge group. The main emphasis is on the so-called hybrid ψ χ η model. The possible patterns of realization of the continuous chiral flavor symmetry are discussed. We argue that the chiral symmetry is broken in conjunction with a dynamical Higgsing of the gauge group (complete or partial) by bifermion condensates. As a result a color-flavor locked symmetry is preserved. The 't Hooft anomaly matching proceeds via saturation of triangles by massless composite fermions or, in a mixed mode, i.e. also by the "weakly" coupled fermions associated with dynamical Abelianization, supplemented by a number of Nambu-Goldstone mesons. Gauge-singlet condensates are of the multifermion type and, though it cannot be excluded, the chiral symmetry realization via such gauge invariant condensates is more contrived (requires a number of four-fermion condensates simultaneously and, even so, problems remain) and less plausible. We conclude that in the model at hand, chiral flavor symmetry implies dynamical Higgsing by bifermion condensates.

Flavor-singlet spectrum in multi-flavor QCD

NASA Astrophysics Data System (ADS)

Aoki, Yasumichi; Aoyama, Tatsumi; Bennett, Ed; Kurachi, Masafumi; Maskawa, Toshihide; Miura, Kohtaroh; Nagai, Kei-ichi; Ohki, Hiroshi; Rinaldi, Enrico; Shibata, Akihiro; Yamawaki, Koichi; Yamazaki, Takeshi

2018-03-01

Studying SU(3) gauge theories with increasing number of light fermions is relevant both for understanding the strong dynamics of QCD and for constructing strongly interacting extensions of the Standard Model (e.g. UV completions of composite Higgs models). In order to contrast these many-flavors strongly interacting theories with QCD, we study the flavor-singlet spectrum as an interesting probe. In fact, some composite Higgs models require the Higgs boson to be the lightest flavor-singlet scalar in the spectrum of a strongly interacting new sector with a well defined hierarchy with the rest of the states. Moreover, introducing many light flavors at fixed number of colors can influence the dynamics of the lightest flavor-singlet pseudoscalar. We present the on-going study of these flavor-singlet channels using multiple interpolating operators on high-statistics ensembles generated by the LatKMI collaboration and we compare results with available data obtained by the Lattice Strong Dynamics collaboration. For the theory with 8 flavors, the two collaborations have generated configurations that complement each others with the aim to tackle the massless limit using the largest possible volumes.

Flavor-singlet spectrum in multi-flavor QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aoki, Yasamichi; Rinaldi, Enrico

2017-06-18

Studying SU(3) gauge theories with increasing number of light fermions is relevant both for understanding the strong dynamics of QCD and for constructing strongly interacting extensions of the Standard Model (e.g. UV completions of composite Higgs models). In order to contrast these many-flavors strongly interacting theories with QCD, we study the flavor-singlet spectrum as an interesting probe. In fact, some composite Higgs models require the Higgs boson to be the lightest flavor-singlet scalar in the spectrum of a strongly interacting new sector with a well defined hierarchy with the rest of the states. Moreover, introducing many light flavors at fixedmore » number of colors can influence the dynamics of the lightest flavor-singlet pseudoscalar. We present the on-going study of these flavor-singlet channels using multiple interpolating operators on high-statistics ensembles generated by the LatKMI collaboration and we compare results with available data obtained by the Lattice Strong Dynamics collaboration. For the theory with 8 flavors, the two collaborations have generated configurations that complement each others with the aim to tackle the massless limit using the largest possible volumes.« less

Hidden charged dark matter and chiral dark radiation

NASA Astrophysics Data System (ADS)

Ko, P.; Nagata, Natsumi; Tang, Yong

2017-10-01

In the light of recent possible tensions in the Hubble constant H0 and the structure growth rate σ8 between the Planck and other measurements, we investigate a hidden-charged dark matter (DM) model where DM interacts with hidden chiral fermions, which are charged under the hidden SU(N) and U(1) gauge interactions. The symmetries in this model assure these fermions to be massless. The DM in this model, which is a Dirac fermion and singlet under the hidden SU(N), is also assumed to be charged under the U(1) gauge symmetry, through which it can interact with the chiral fermions. Below the confinement scale of SU(N), the hidden quark condensate spontaneously breaks the U(1) gauge symmetry such that there remains a discrete symmetry, which accounts for the stability of DM. This condensate also breaks a flavor symmetry in this model and Nambu-Goldstone bosons associated with this flavor symmetry appear below the confinement scale. The hidden U(1) gauge boson and hidden quarks/Nambu-Goldstone bosons are components of dark radiation (DR) above/below the confinement scale. These light fields increase the effective number of neutrinos by δNeff ≃ 0.59 above the confinement scale for N = 2, resolving the tension in the measurements of the Hubble constant by Planck and Hubble Space Telescope if the confinement scale is ≲1 eV. DM and DR continuously scatter with each other via the hidden U(1) gauge interaction, which suppresses the matter power spectrum and results in a smaller structure growth rate. The DM sector couples to the Standard Model sector through the exchange of a real singlet scalar mixing with the Higgs boson, which makes it possible to probe our model in DM direct detection experiments. Variants of this model are also discussed, which may offer alternative ways to investigate this scenario.

Kicking the rugby ball: perturbations of 6D gauged chiral supergravity

NASA Astrophysics Data System (ADS)

Burgess, C. P.; de Rham, C.; Hoover, D.; Mason, D.; Tolley, A. J.

2007-02-01

We analyse the axially symmetric scalar perturbations of 6D chiral gauged supergravity compactified on the general warped geometries in the presence of two source branes. We find that all of the conical geometries are marginally stable for normalizable perturbations (in disagreement with some recent calculations) and the non-conical ones for regular perturbations, even though none of them are supersymmetric (apart from the trivial Salam Sezgin solution, for which there are no source branes). The marginal direction is the one whose presence is required by the classical scaling property of the field equations, and all other modes have positive squared mass. In the special case of the conical solutions, including (but not restricted to) the unwarped 'rugby-ball' solutions, we find closed-form expressions for the mode functions in terms of Legendre and hypergeometric functions. In so doing we show how to match the asymptotic near-brane form for the solution to the physics of the source branes, and thereby how to physically interpret perturbations which can be singular at the brane positions.

Chiral behavior of K →π l ν decay form factors in lattice QCD with exact chiral symmetry

NASA Astrophysics Data System (ADS)

Aoki, S.; Cossu, G.; Feng, X.; Fukaya, H.; Hashimoto, S.; Kaneko, T.; Noaki, J.; Onogi, T.; Jlqcd Collaboration

2017-08-01

We calculate the form factors of the K →π l ν semileptonic decays in three-flavor lattice QCD and study their chiral behavior as a function of the momentum transfer and the Nambu-Goldstone boson masses. Chiral symmetry is exactly preserved by using the overlap quark action, which enables us to directly compare the lattice data with chiral perturbation theory (ChPT). We generate gauge ensembles at a lattice spacing of 0.11 fm with four pion masses covering 290-540 MeV and a strange quark mass ms close to its physical value. By using the all-to-all quark propagator, we calculate the vector and scalar form factors with high precision. Their dependence on ms and the momentum transfer is studied by using the reweighting technique and the twisted boundary conditions for the quark fields. We compare the results for the semileptonic form factors with ChPT at next-to-next-to-leading order in detail. While many low-energy constants appear at this order, we make use of our data of the light meson electromagnetic form factors in order to control the chiral extrapolation. We determine the normalization of the form factors as f+(0 )=0.9636 (36 )(-35+57) and observe reasonable agreement of their shape with experiment.

Generalized polarizabilities of the nucleon in baryon chiral perturbation theory

NASA Astrophysics Data System (ADS)

Lensky, Vadim; Pascalutsa, Vladimir; Vanderhaeghen, Marc

2017-02-01

The nucleon generalized polarizabilities (GPs), probed in virtual Compton scattering (VCS), describe the spatial distribution of the polarization density in a nucleon. They are accessed experimentally via the process of electron-proton bremsstrahlung (ep→ epγ ) at electron-beam facilities, such as MIT-Bates, CEBAF (Jefferson Lab), and MAMI (Mainz). We present the calculation of the nucleon GPs and VCS observables at next-to-leading order in baryon chiral perturbation theory (Bχ PT), and confront the results with the empirical information. At this order our results are predictions, in the sense that all the parameters are well known from elsewhere. Within the relatively large uncertainties of our calculation we find good agreement with the experimental observations of VCS and the empirical extractions of the GPs. We find large discrepancies with previous chiral calculations - all done in heavy-baryon χ PT (HBχ PT) - and discuss the differences between Bχ PT and HBχ PT responsible for these discrepancies.

Elastic pion-nucleon scattering in chiral perturbation theory: A fresh look

NASA Astrophysics Data System (ADS)

Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A.; Krebs, H.; Meißner, Ulf-G.

2016-07-01

Elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order within the heavy-baryon expansion and a covariant approach based on an extended on-mass-shell renormalization scheme. We discuss in detail the renormalization of the various low-energy constants and provide explicit expressions for the relevant β functions and the finite subtractions of the power-counting breaking terms within the covariant formulation. To estimate the theoretical uncertainty from the truncation of the chiral expansion, we employ an approach which has been successfully applied in the most recent analysis of the nuclear forces. This allows us to reliably extract the relevant low-energy constants from the available scattering data at low energy. The obtained results provide clear evidence that the breakdown scale of the chiral expansion for this reaction is related to the Δ resonance. The explicit inclusion of the leading contributions of the Δ isobar is demonstrated to substantially increase the range of applicability of the effective field theory. The resulting predictions for the phase shifts are in an excellent agreement with the predictions from the recent Roy-Steiner-equation analysis of pion-nucleon scattering.

Light flavor-singlet scalars and walking signals in N f = 8 QCD on the lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aoki, Yasumichi; Aoyama, Tatsumi; Bennett, Ed

Based on the highly improved staggered quark action, we perform in this paper lattice simulations of N f = 8 QCD and confirm our previous observations, both of a flavor-singlet scalar meson (denoted as σ) as light as the pion and of various “walking signals” through the low-lying spectra, with higher statistics, smaller fermion masses m f, and larger volumes. We measure M π, F π, M ρ, M a0, M a1, M b1, M N, M σ, F σ, (φφ) (both directly and through the Gell-Mann-Oakes-Renner relation), and the string tension. The data are consistent with the spontaneously brokenmore » phase of the chiral symmetry, in agreement with the previous results: Ratios of the quantities to M π monotonically increase in the smaller m f region towards the chiral limit similarly to N f = 4 QCD, in sharp contrast to N f = 12 QCD where the ratios become flattened. We perform fits to chiral perturbation theory, with the value of F π found in the chiral limit extrapolation reduced dramatically to roughly 2/3 of the previous result, suggesting the theory is much closer to the conformal window. In fact, each quantity obeys the respective hyperscaling relation throughout a more extensive m f region compared with earlier works. The hyperscaling relation holds with roughly a universal value of the anomalous dimension, γ m ≃ 1, with the notable exception of M π with γ m ≃ 0.6 as in the previous results, which reflects the above growing up of the ratios towards the chiral limit. This is a salient feature (walking signal) of N f = 8, unlike either N f = 4, which has no hyperscaling relation at all, or N f = 12 QCD, which exhibits universal hyperscaling. The effective γ m Ξ γ m(m f) of M π defined for each m f region has a tendency to grow towards unity near the chiral limit, in conformity with the Nambu-Goldstone boson nature, as opposed to the case of N f = 12 QCD where it is almost constant. We further confirm the previous observation of the light σ with mass comparable to

Light flavor-singlet scalars and walking signals in N f = 8 QCD on the lattice

DOE PAGES

Aoki, Yasumichi; Aoyama, Tatsumi; Bennett, Ed; ...

2017-07-18

Based on the highly improved staggered quark action, we perform in this paper lattice simulations of N f = 8 QCD and confirm our previous observations, both of a flavor-singlet scalar meson (denoted as σ) as light as the pion and of various “walking signals” through the low-lying spectra, with higher statistics, smaller fermion masses m f, and larger volumes. We measure M π, F π, M ρ, M a0, M a1, M b1, M N, M σ, F σ, (φφ) (both directly and through the Gell-Mann-Oakes-Renner relation), and the string tension. The data are consistent with the spontaneously brokenmore » phase of the chiral symmetry, in agreement with the previous results: Ratios of the quantities to M π monotonically increase in the smaller m f region towards the chiral limit similarly to N f = 4 QCD, in sharp contrast to N f = 12 QCD where the ratios become flattened. We perform fits to chiral perturbation theory, with the value of F π found in the chiral limit extrapolation reduced dramatically to roughly 2/3 of the previous result, suggesting the theory is much closer to the conformal window. In fact, each quantity obeys the respective hyperscaling relation throughout a more extensive m f region compared with earlier works. The hyperscaling relation holds with roughly a universal value of the anomalous dimension, γ m ≃ 1, with the notable exception of M π with γ m ≃ 0.6 as in the previous results, which reflects the above growing up of the ratios towards the chiral limit. This is a salient feature (walking signal) of N f = 8, unlike either N f = 4, which has no hyperscaling relation at all, or N f = 12 QCD, which exhibits universal hyperscaling. The effective γ m Ξ γ m(m f) of M π defined for each m f region has a tendency to grow towards unity near the chiral limit, in conformity with the Nambu-Goldstone boson nature, as opposed to the case of N f = 12 QCD where it is almost constant. We further confirm the previous observation of the light σ with mass comparable to

Chiral extrapolations of the ρ ( 770 ) meson in N f = 2 + 1 lattice QCD simulations

DOE PAGES

Hu, B.; Molina, R.; Döring, M.; ...

2017-08-24

Recentmore » $$N_f=2+1$$ lattice data for meson-meson scattering in $p$-wave and isospin $I=1$ are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. We perform chiral extrapolations that postdict phase shifts extracted from experiment quite well. Additionally, the low-energy constants are compared to the ones from a recent analysis of $$N_f=2$$ lattice QCD simulations to check for the consistency of the hadronic model used here. Some inconsistencies are detected in the fits to $$N_f=2+1$$ data, in contrast to the previous analysis of $$N_f=2$$ data.« less

One-loop perturbative coupling of A and A? through the chiral overlap operator

NASA Astrophysics Data System (ADS)

Makino, Hiroki; Morikawa, Okuto; Suzuki, Hiroshi

2018-03-01

Recently, Grabowska and Kaplan constructed a four-dimensional lattice formulation of chiral gauge theories on the basis of the chiral overlap operator. At least in the tree-level approximation, the left-handed fermion is coupled only to the original gauge field A, while the right-handed one is coupled only to the gauge field A*, a deformation of A by the gradient flow with infinite flow time. In this paper, we study the fermion one-loop effective action in their formulation. We show that the continuum limit of this effective action contains local interaction terms between A and A*, even if the anomaly cancellation condition is met. These non-vanishing terms would lead an undesired perturbative spectrum in the formulation.

Exotic Higgs boson decay modes as a harbinger of S{sub 3} flavor symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Gautam; Leser, Philipp; Paes, Heinrich

2011-01-01

Discrete symmetries employed to explain flavor mixing and mass hierarchies can be associated with an enlarged scalar sector which might lead to exotic Higgs decay modes. In this paper, we explore such a possibility in a scenario with S{sub 3} flavor symmetry which requires three scalar SU(2) doublets. The spectrum is fixed by minimizing the scalar potential, and we observe that the symmetry of the model leads to tantalizing Higgs decay modes potentially observable at the CERN Large Hadron Collider.

Critical flavor number of the Thirring model in three dimensions

NASA Astrophysics Data System (ADS)

Wellegehausen, Björn H.; Schmidt, Daniel; Wipf, Andreas

2017-11-01

The Thirring model is a four-fermion theory with a current-current interaction and U (2 N ) chiral symmetry. It is closely related to three-dimensional QED and other models used to describe properties of graphene. In addition, it serves as a toy model to study chiral symmetry breaking. In the limit of flavor number N →1 /2 it is equivalent to the Gross-Neveu model, which shows a parity-breaking discrete phase transition. The model was already studied with different methods, including Dyson-Schwinger equations, functional renormalization group methods, and lattice simulations. Most studies agree that there is a phase transition from a symmetric phase to a spontaneously broken phase for a small number of fermion flavors, but no symmetry breaking for large N . But there is no consensus on the critical flavor number Ncr above which there is no phase transition anymore and on further details of the critical behavior. Values of N found in the literature vary between 2 and 7. All earlier lattice studies were performed with staggered fermions. Thus it is questionable if in the continuum limit the lattice model recovers the internal symmetries of the continuum model. We present new results from lattice Monte Carlo simulations of the Thirring model with SLAC fermions which exactly implement all internal symmetries of the continuum model even at finite lattice spacing. If we reformulate the model in an irreducible representation of the Clifford algebra, we find, in contradiction to earlier results, that the behavior for even and odd flavor numbers is very different: for even flavor numbers, chiral and parity symmetry are always unbroken; for odd flavor numbers, parity symmetry is spontaneously broken below the critical flavor number Nircr=9 , while chiral symmetry is still unbroken.

Nucleon and Delta axial-vector couplings in 1/N{sub c}-Baryon Chiral Perturbation Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goity, Jose Luis; Calle Cordon, Alvaro

In this contribution, baryon axial-vector couplings are studied in the framework of the combined 1/N{sub c} and chiral expansions. This framework is implemented on the basis of the emergent spin-flavor symmetry in baryons at large N{sub c} and HBChPT, and linking both expansions ({xi}-expansion), where 1/N{sub c} is taken to be a quantity order p. The study is carried out including one-loop contributions, which corresponds to order xi to the third for baryon masses and order {xi} square for the axial couplings.

Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

NASA Astrophysics Data System (ADS)

Bijnens, Johan; Rössler, Thomas

2015-11-01

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique.

Chiral interface at the finite temperature transition point of QCD

NASA Technical Reports Server (NTRS)

Frei, Z.; Patkos, A.

1990-01-01

The domain wall between coexisting chirally symmetric and broken symmetry regions is studied in a saddle point approximation to the effective three-flavor sigma model. In the chiral limit the surface tension varies in the range ((40 to -50)MeV)(exp 3). The width of the domain wall is estimated to be approximately or equal to 4.5 fm.

Beyond minimal lepton-flavored Dark Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Mu-Chun; Huang, Jinrui; Takhistov, Volodymyr

In this paper ,we consider a class of flavored dark matter (DM) theories where dark matter interacts with the Standard Model lepton fields at the renormalizable level. We allow for a general coupling matrix between the dark matter and leptons whose structure is beyond the one permitted by the minimal flavor violation (MFV) assumption. It is assumed that this is the only new source of flavor violation in addition to the Standard Model (SM) Yukawa interactions. The setup can be described by augmenting the SM flavor symmetry by an additional SU(3) χ, under which the dark matter χ transforms. Thismore » framework is especially phenomenologically rich, due to possible novel flavor-changing interactions which are not present within the more restrictive MFV framework. As a representative case study of this setting, which we call “beyond MFV” (BMFV), we consider Dirac fermion dark matter which transforms as a singlet under the SM gauge group and a triplet under SU(3) χ. The DM fermion couples to the SM lepton sector through a scalar mediator Φ. Unlike the case of quark-flavored DM, we show that there is no Z 3 symmetry within either the MFV or BMFV settings which automatically stabilizes the lepton-flavored DM. We discuss constraints on this setup from flavor-changing processes, DM relic abundance as well as direct and indirect detections. We find that relatively large flavor-changing couplings are possible, while the dark matter mass is still within the phenomenologically interesting region below the TeV scale. Collider signatures which can be potentially searched for at the lepton and hadron colliders are discussed. Finally, we discuss the implications for decaying dark matter, which can appear if an additional stabilizing symmetry is not imposed.« less

Beyond minimal lepton-flavored Dark Matter

DOE PAGES

Chen, Mu-Chun; Huang, Jinrui; Takhistov, Volodymyr

2016-02-09

In this paper ,we consider a class of flavored dark matter (DM) theories where dark matter interacts with the Standard Model lepton fields at the renormalizable level. We allow for a general coupling matrix between the dark matter and leptons whose structure is beyond the one permitted by the minimal flavor violation (MFV) assumption. It is assumed that this is the only new source of flavor violation in addition to the Standard Model (SM) Yukawa interactions. The setup can be described by augmenting the SM flavor symmetry by an additional SU(3) χ, under which the dark matter χ transforms. Thismore » framework is especially phenomenologically rich, due to possible novel flavor-changing interactions which are not present within the more restrictive MFV framework. As a representative case study of this setting, which we call “beyond MFV” (BMFV), we consider Dirac fermion dark matter which transforms as a singlet under the SM gauge group and a triplet under SU(3) χ. The DM fermion couples to the SM lepton sector through a scalar mediator Φ. Unlike the case of quark-flavored DM, we show that there is no Z 3 symmetry within either the MFV or BMFV settings which automatically stabilizes the lepton-flavored DM. We discuss constraints on this setup from flavor-changing processes, DM relic abundance as well as direct and indirect detections. We find that relatively large flavor-changing couplings are possible, while the dark matter mass is still within the phenomenologically interesting region below the TeV scale. Collider signatures which can be potentially searched for at the lepton and hadron colliders are discussed. Finally, we discuss the implications for decaying dark matter, which can appear if an additional stabilizing symmetry is not imposed.« less

Boundary states in the chiral symmetric systems with a spatial symmetry

NASA Astrophysics Data System (ADS)

Xiao, Jinpeng; An, Jin

2018-02-01

We study topological systems with both a chiral and a spatial symmetry which result in an additional spatial chiral symmetry. We distinguish the topologically nontrivial states according to the chiral symmetries protecting them and study several models in 1D and 3D systems. The perturbations breaking the spatial symmetry can break only one of the two chiral symmetries while the perturbations preserving the spatial symmetry always break or preserve both of them. In 3D systems, besides the 3D symmetries, the topologically nontrivial boundary modes may also be protected by the hidden lower dimensional symmetries. We then figure out the corresponding topological invariants and connect them with the 3D invariants.

Flavor-singlet meson decay constants from Nf=2 +1 +1 twisted mass lattice QCD

NASA Astrophysics Data System (ADS)

Ottnad, Konstantin; Urbach, Carsten; ETM Collaboration

2018-03-01

We present an improved analysis of our lattice data for the η - η' system, including a correction of the relevant correlation functions for residual topological finite size effects and employing consistent chiral and continuum fits. From this analysis we update our physical results for the masses Mη=557 (11 )stat(03 )χ PT MeV and Mη'=911 (64 )stat(03 )χ PT MeV , as well as the mixing angle in the quark flavor basis ϕ =38.8 (2.2 )stat(2.4 )χPT ∘ in excellent agreement with other results from phenomenology. Similarly, we include an analysis for the decay constant parameters, leading to fl=125 (5 )stat(6 )χ PT MeV and fs=178 (4 )stat(1 )χ PT MeV . The second error reflects the uncertainty related to the chiral extrapolation. The data used for this study has been generated on gauge ensembles provided by the European Twisted Mass Collaboration with Nf=2 +1 +1 dynamical flavors of Wilson twisted mass fermions. These ensembles cover a range of pion masses from 220 MeV to 500 MeV and three values of the lattice spacing. Combining our data with a prediction from chiral perturbation theory, we give an estimate for the physical η , η'→γ γ decay widths and the singly-virtual η , η'→γ γ* transition form factors in the limit of large momentum transfer.

Linear flavor-wave theory for fully antisymmetric SU(N ) irreducible representations

NASA Astrophysics Data System (ADS)

Kim, Francisco H.; Penc, Karlo; Nataf, Pierre; Mila, Frédéric

2017-11-01

The extension of the linear flavor-wave theory to fully antisymmetric irreducible representations (irreps) of SU (N ) is presented in order to investigate the color order of SU (N ) antiferromagnetic Heisenberg models in several two-dimensional geometries. The square, triangular, and honeycomb lattices are considered with m fermionic particles per site. We present two different methods: the first method is the generalization of the multiboson spin-wave approach to SU (N ) which consists of associating a Schwinger boson to each state on a site. The second method adopts the Read and Sachdev bosons which are an extension of the Schwinger bosons that introduces one boson for each color and each line of the Young tableau. The two methods yield the same dispersing modes, a good indication that they properly capture the semiclassical fluctuations, but the first one leads to spurious flat modes of finite frequency not present in the second one. Both methods lead to the same physical conclusions otherwise: long-range Néel-type order is likely for the square lattice for SU(4) with two particles per site, but quantum fluctuations probably destroy order for more than two particles per site, with N =2 m . By contrast, quantum fluctuations always lead to corrections larger than the classical order parameter for the tripartite triangular lattice (with N =3 m ) or the bipartite honeycomb lattice (with N =2 m ) for more than one particle per site, m >1 , making the presence of color very unlikely except maybe for m =2 on the honeycomb lattice, for which the correction is only marginally larger than the classical order parameter.

$${{\\bar{d}} - {\\bar{u}}}$$ Flavor Asymmetry in the Proton in Chiral Effective Field Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salamu, Y.; Ji, Cheung-Ryong; Melnitchouk, Wally

2015-09-01

Themore » $${\\bar d - \\bar u}$$ flavor asymmetry in the proton arising from pion loops is computed using chiral effective field theory. calculation includes both nucleon and Δ intermediate states, and uses both the fully relativistic and heavy baryon frameworks. x dependence of $${\\bar d - \\bar u}$$ extracted from the Fermilab E866 Drell–Yan data can be well reproduced in terms of a single transverse momentum cutoff parameter regulating the ultraviolet behavior of the loop integrals. In addition to the distribution at x > 0, corrections to the integrated asymmetry from zero momentum contributions are computed, which arise from pion rainbow and bubble diagrams at x = 0. These have not been accounted for in previous analyses, and can make important contributions to the lowest moment of $${\\bar d-\\bar u}$$ .« less

QCD topological susceptibility from the nonlocal chiral quark model

NASA Astrophysics Data System (ADS)

Nam, Seung-Il; Kao, Chung-Wen

2017-06-01

We investigate the quantum chromodynamics (QCD) topological susceptibility χ by using the semi-bosonized nonlocal chiral-quark model (SB-NLχQM) for the leading large- N c contributions. This model is based on the liquid-instanton QCD-vacuum configuration, in which SU(3) flavor symmetry is explicitly broken by the finite current-quark mass ( m u,d, m s) ≈ (5, 135) MeV. To compute χ, we derive the local topological charge-density operator Q t( x) from the effective action of SB-NLχQM. We verify that the derived expression for χ in our model satisfies the Witten- Veneziano (WV) and the Leutwyler-Smilga (LS) formulae, and the Crewther theorem in the chiral limit by construction. Once the average instanton size and the inter-instanton distance are fixed with ρ¯ = 1/3 fm and R¯ = 1 fm, respectively, all the other parameters are determined self-consistently within the model. We obtain χ = (167.67MeV)4, which is comparable with the empirical value χ = (175±5MeV)4 whereas it turns out that χ QL = (194.30MeV)4 in the quenched limit. Thus, we conclude that the value of χ will be reduced around 10 20% by the dynamical-quark contribution.

Chiral phase transition at finite chemical potential in 2 +1 -flavor soft-wall anti-de Sitter space QCD

NASA Astrophysics Data System (ADS)

Bartz, Sean P.; Jacobson, Theodore

2018-04-01

The phase transition from hadronic matter to chirally symmetric quark-gluon plasma is expected to be a rapid crossover at zero quark chemical potential (μ ), becoming first order at some finite value of μ , indicating the presence of a critical point. Using a three-flavor soft-wall model of anti-de Sitter/QCD, we investigate the effect of varying the light and strange quark masses on the order of the chiral phase transition. At zero quark chemical potential, we reproduce the Columbia Plot, which summarizes the results of lattice QCD and other holographic models. We then extend this holographic model to examine the effects of finite quark chemical potential. We find that the the chemical potential does not affect the critical line that separates first-order from rapid crossover transitions. This excludes the possibility of a critical point in this model, suggesting that a different setup is necessary to reproduce all the features of the QCD phase diagram.

Effects of renormalizing the chiral SU(2) quark-meson model

NASA Astrophysics Data System (ADS)

Zacchi, Andreas; Schaffner-Bielich, Jürgen

2018-04-01

We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark-meson model, where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite temperature, all the renormalized versions show a crossover transition. The inclusion of different renormalization scales leave the order parameter and the mass spectra nearly untouched but strongly influence the thermodynamics at low temperatures and around the phase transition. We find unphysical results for the renormalized version of mesons and the combined one.

Anisotropic D3-D5 black holes with unquenched flavors

NASA Astrophysics Data System (ADS)

Penín, José Manuel; Ramallo, Alfonso V.; Zoakos, Dimitrios

2018-02-01

We construct a black hole geometry generated by the intersection of N c color D3- branes and N f flavor D5-branes along a 2+1 dimensional subspace. Working in the Veneziano limit in which N f is large and distributing homogeneously the D5-branes in the internal space, we calculate the solution of the equations of motion of supergravity plus sources which includes the backreaction of the flavor branes. The solution is analytic and dual to a 2+1 dimensional defect in a 3+1 dimensional gauge theory, with N f massless hypermultiplets living in the defect. The smeared background we obtain can be regarded as the holographic realization of a multilayered system. We study the thermodynamics of the resulting spatially anisotropic geometry and compute the first and second order transport coefficients for perturbations propagating along the defect. We find that, in our system, the dynamics of excitations within a layer can be described by a stack of effective D2-branes.

Low-energy neutron-deuteron reactions with N 3LO chiral forces

DOE PAGES

Golak, J.; Skibinski, R.; Topolnicki, K.; ...

2014-11-27

Here, we solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on A y puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported.

Effects of Composite Pions on the Chiral Condensate within the PNJL Model at Finite Temperature

NASA Astrophysics Data System (ADS)

Blaschke, D.; Dubinin, A.; Ebert, D.; Friesen, A. V.

2018-05-01

We investigate the effect of composite pions on the behaviour of the chiral condensate at finite temperature within the Polyakov-loop improved NJL model. To this end we treat quark-antiquark correlations in the pion channel (bound states and scattering continuum) within a Beth-Uhlenbeck approach that uses medium-dependent phase shifts. A striking medium effect is the Mott transition which occurs when the binding energy vanishes and the discrete pion bound state merges the continuum. This transition is triggered by the lowering of the continuum edge due to the chiral restoration transition. This in turn also entails a modification of the Polyakov-loop so that the SU(3) center symmetry gets broken at finite temperature and dynamical quarks (and gluons) appear in the system, taking over the role of the dominant degrees of freedom from the pions. At low temperatures our model reproduces the chiral perturbation theory result for the chiral condensate while at high temperatures the PNJL model result is recovered. The new aspect of the current work is a consistent treatment of the chiral restoration transition region within the Beth-Uhlenbeck approach on the basis of mesonic phase shifts for the treatment of the correlations.

Chiral symmetry breaking in QCD with two light flavors.

PubMed

Engel, Georg P; Giusti, Leonardo; Lottini, Stefano; Sommer, Rainer

2015-03-20

A distinctive feature of the presence of spontaneous chiral symmetry breaking in QCD is the condensation of low modes of the Dirac operator near the origin. The rate of condensation must be equal to the slope of M(π)(2)F(π)(2)/2 with respect to the quark mass m in the chiral limit, where M(π) and F(π) are the mass and the decay constant of the Nambu-Goldstone bosons. We compute the spectral density of the (Hermitian) Dirac operator, the quark mass, the pseudoscalar meson mass, and decay constant by numerical simulations of lattice QCD with two light degenerate Wilson quarks. We use lattices generated by the Coordinated Lattice Simulation (CLS) group at three values of the lattice spacing in the range 0.05-0.08 fm, and for several quark masses corresponding to pseudoscalar mesons masses down to 190 MeV. Thanks to this coverage of parameters space, we can extrapolate all quantities to the chiral and continuum limits with confidence. The results show that the low quark modes do condense in the continuum as expected by the Banks-Casher mechanism, and the rate of condensation agrees with the Gell-Mann-Oakes-Renner relation. For the renormalization-group-invariant ratios we obtain [Σ(RGI)](1/3)/F=2.77(2)(4) and Λ(M̅S)/F=3.6(2), which correspond to [Σ(M̅S)(2  GeV)](1/3)=263(3)(4)  MeV and F=85.8(7)(20)  MeV if F(K) is used to set the scale by supplementing the theory with a quenched strange quark.

Neutron matter with Quantum Monte Carlo: chiral 3N forces and static response

DOE PAGES

Buraczynski, M.; Gandolfi, S.; Gezerlis, A.; ...

2016-03-14

Neutron matter is related to the physics of neutron stars and that of neutron-rich nuclei. Moreover, Quantum Monte Carlo (QMC) methods offer a unique way of solving the many-body problem non-perturbatively, providing feedback on features of nuclear interactions and addressing scenarios that are inaccessible to other approaches. Our contribution goes over two recent accomplishments in the theory of neutron matter: a) the fusing of QMC with chiral effective field theory interactions, focusing on local chiral 3N forces, and b) the first attempt to find an ab initio solution to the problem of static response.

B -meson decay constants from 2 + 1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

DOE PAGES

Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; ...

2015-03-10

We calculate the B-meson decay constants f B, f Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M π ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clovermore » action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(α sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain f B0 = 199.5(12.6) MeV, f B+=195.6(14.9) MeV, f Bs=235.4(12.2) MeV, f Bs/f B0=1.197(50), and f Bs/f B+=1.223(71), where the errors are statistical and total systematic added in quadrature. Finally, these results are in good agreement with other published results and provide an important independent cross-check of other three-flavor determinations of B-meson decay constants using staggered light quarks.« less

B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku

2015-03-10

We calculate the B-meson decay constants f B, f Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M π ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action withmore » the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(α sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain f B0 = 196.2(15.7) MeV, f B+ = 195.4(15.8) MeV, f Bs = 235.4(12.2) MeV, f Bs/f B0 = 1.193(59), and f Bs/f B+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.« less

Effects of Fluctuations on Inhomogeneous Chiral Transitions

NASA Astrophysics Data System (ADS)

Lee, Tong-Gyu; Yoshiike, Ryo; Tatsumi, Toshitaka

We discuss the features of the order-parameter fluctuations in the normal phase near the phase boundary and their effects on the phase transition from the normal to the inhomogeneous phase with spatially modulated order parameter. Focusing on the chiral symmetry breaking, i.e., inhomogeneous chiral transition, we consider the fluctuation of the chiral pair consisting of quark-antiquark or quark-hole pair within the two-flavor Nambu-Jona-Lasinio model in the chiral limit. We clarify the roles of quantum and thermal fluctuations and also argue that anomalies for thermodynamic quantities in the inhomogeneous chiral transition should lead to phenomenological implications.

Analytic representations of mK , FK, mη, and Fη in two loop S U (3 ) chiral perturbation theory

NASA Astrophysics Data System (ADS)

Ananthanarayan, B.; Bijnens, Johan; Friot, Samuel; Ghosh, Shayan

2018-06-01

In this work, we consider expressions for the masses and decay constants of the pseudoscalar mesons in S U (3 ) chiral perturbation theory. These involve sunset diagrams and their derivatives evaluated at p2=mP2 (P =π , K , η ). Recalling that there are three mass scales in this theory, mπ, mK and mη, there are instances when the finite part of the sunset diagrams do not admit an expression in terms of elementary functions, and have therefore been evaluated numerically in the past. In a recent publication, an expansion in the external momentum was performed to obtain approximate analytic expressions for mπ and Fπ, the pion mass and decay constant. We provide fully analytic exact expressions for mK and mη, the kaon and eta masses, and FK and Fη, the kaon and eta decay constants. These expressions, calculated using Mellin-Barnes methods, are in the form of double series in terms of two mass ratios. A numerical analysis of the results to evaluate the relative size of contributions coming from loops, chiral logarithms as well as phenomenological low-energy constants is presented. We also present a set of approximate analytic expressions for mK, FK, mη and Fη that facilitate comparisons with lattice results. Finally, we show how exact analytic expressions for mπ and Fπ may be obtained, the latter having been used in conjunction with the results for FK to produce a recently published analytic representation of FK/Fπ.

Update on SU(2) gauge theory with NF = 2 fundamental flavours.

NASA Astrophysics Data System (ADS)

Drach, Vincent; Janowski, Tadeusz; Pica, Claudio

2018-03-01

We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. This theory provides a minimal template which is ideal for a wide class of Standard Model extensions featuring novel strong dynamics, such as a minimal realization of composite Higgs models. We present an update on the status of the meson spectrum and decay constants based on increased statistics on our existing ensembles and the inclusion of new ensembles with lighter pion masses, resulting in a more reliable chiral extrapolation. Preprint: CP3-Origins-2017-048 DNRF90

Periodic chiral structures

NASA Technical Reports Server (NTRS)

Jaggard, Dwight L.; Engheta, Nader; Pelet, Philippe; Liu, John C.; Kowarz, Marek W.; Kim, Yunjin

1989-01-01

The electromagnetic properties of a structure that is both chiral and periodic are investigated using coupled-mode equations. The periodicity is described by a sinusoidal perturbation of the permittivity, permeability, and chiral admittance. The coupled-mode equations are derived from physical considerations and used to examine bandgap structure and reflected and transmitted fields. Chirality is observed predominantly in transmission, whereas periodicity is present in both reflection and transmission.

Intrinsic Optical Activity and Environmental Perturbations: Solvation Effects in Chiral Building Blocks

NASA Astrophysics Data System (ADS)

Lemler, Paul M.; Vaccaro, Patrick

2016-06-01

The non-resonant interaction of electromagnetic radiation with an isotropic ensemble of chiral molecules, which causes the incident state of linear polarization to undergo a signed rotation, long has served as a metric for gauging the enantiomeric purity of asymmetric syntheses. While the underlying phenomenon of circular birefringence (CB) typically is probed in the condensed phase, recent advances in ultrasensitive circular-differential detection schemes, as exemplified by the techniques of Cavity Ring-Down Polarimetry (CRDP), have permitted the first quantitative analyses of such processes to be performed in rarefied media. Efforts to extend vapor-phase investigations of CB to new families of chiral substrates will be discussed, with particular emphasis directed towards the elucidation of intrinsic (e.g., solvent-free) properties and their mediation by environmental perturbations (e.g., solvation). Specific species targeted by this work will include the stereoselective building blocks phenylpropylene oxide and α-methylbenzyl amine, both of which exhibit pronounced solvent-dependent changes in measured optical activity. The nature of chiroptical response in different environments will be highlighted, with quantum-chemical calculations serving to unravel the structural and electronic provenance of observed behavior.

Dense baryon matter with isospin and chiral imbalance in the framework of a NJL4 model at large Nc: Duality between chiral symmetry breaking and charged pion condensation

NASA Astrophysics Data System (ADS)

Khunjua, T. G.; Klimenko, K. G.; Zhokhov, R. N.

2018-03-01

In this paper the phase structure of dense quark matter has been investigated at zero temperature in the presence of baryon, isospin and chiral isospin chemical potentials in the framework of massless (3 +1 )-dimensional Nambu-Jona-Lasinio model with two quark flavors. It has been shown that in the large-Nc limit (Nc is the number of colors of quarks) there exists a duality correspondence between the chiral symmetry breaking phase and the charged pion condensation one. The key conclusion of our studies is the fact that chiral isospin chemical potential generates charged pion condensation in dense quark matter with isotopic asymmetry.

Explicit chiral symmetry breaking in the Nambu-Jona-Lasinio model

NASA Astrophysics Data System (ADS)

Schüren, C.; Arriola, E. Ruiz; Goeke, K.

1992-09-01

We consider a chirally symmetric bosonization of the SU(2) Nambu-Jona-Lasinio model within the Pauli-Villars regularization scheme. Special attention is paid to the way in which chiral symmetry is broken explicitly. The parameters of the model are fixed in the light of chiral perturbation theory by performing a covariant derivative expansion in the presence of external fields. As a by-product we obtain the corresponding low-energy parameters and pion radii as well as some threshold parameters for pion-pion scattering. The nucleon is obtained in terms of the solitonic solutions of the action in the sector with baryon number equal to one. It is found that for a constituent quark mass M ˜ 350 MeV most of the calculated vacuum and pion properties agree reasonably well with the experimental ones and coincide with the region where localized solitons with the right size exist. For this value, however, the scalar and vector pion radii turn out to be very small. A unique determination of the sigma term is proposed, obtaining a value of σ(0) = 41.3 MeV. The scalar nucleon form factor is evaluated in the Breit frame. The extrapolation to the Cheng-Dashen point leads to σ(2 m2) - σ(0) = 7.4 MeV.

Masses and sigma terms of doubly charmed baryons up to O (p4) in manifestly Lorentz-invariant baryon chiral perturbation theory

NASA Astrophysics Data System (ADS)

Yao, De-Liang

2018-02-01

We calculate the masses and sigma terms of the doubly charmed baryons up to next-to-next-to-next-to-leading order [i.e., O (p4) ] in a covariant baryon chiral perturbation theory by using the extended-on-mass-shell renormalization scheme. Their expressions both in infinite and finite volumes are provided for chiral extrapolation in lattice QCD. As a first application, our chiral results of the masses are confronted with the existing lattice QCD data in the presence of finite-volume corrections. Up to O (p3) , all relevant low-energy constants can be well determined. As a consequence, we obtain the physical values for the masses of Ξc c and Ωc c baryons by extrapolating to the physical limit. Our determination of the Ξc c mass is consistent with the recent experimental value by LHCb Collaboration, however, larger than the one by SELEX Collaboration. In addition, we predict the pion-baryon and strangeness-baryon sigma terms, as well as the mass splitting between the Ξc c and Ωc c states. Their quark mass dependences are also discussed. The numerical procedure can be applied to the chiral results of O (p4) order, where more unknown constants are involved, when more data are available for unphysical pion masses.

B{sub K} with two flavors of dynamical overlap fermions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aoki, S.; Riken BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973; Fukaya, H.

2008-05-01

We present a two-flavor QCD calculation of B{sub K} on a 16{sup 3}x32 lattice at a{approx}0.12 fm (or equivalently a{sup -1}=1.67 GeV). Both valence and sea quarks are described by the overlap fermion formulation. The matching factor is calculated nonperturbatively with the so-called RI/MOM scheme. We find that the lattice data are well described by the next-to-leading order (NLO) partially quenched chiral perturbation theory (PQChPT) up to around a half of the strange quark mass (m{sub s}{sup phys}/2). The data at quark masses heavier than m{sub s}{sup phys}/2 are fitted including a part of next-to-next-to-leading order terms. We obtain B{submore » K}{sup MS}(2 GeV)=0.537(4)(40), where the first error is statistical and the second is an estimate of systematic uncertainties from finite volume, fixing topology, the matching factor, and the scale setting.« less

Classification of NLO operators for composite Higgs models

NASA Astrophysics Data System (ADS)

Alanne, Tommi; Bizot, Nicolas; Cacciapaglia, Giacomo; Sannino, Francesco

2018-04-01

We provide a general classification of template operators, up to next-to-leading order, that appear in chiral perturbation theories based on the two flavor patterns of spontaneous symmetry breaking SU (NF)/Sp (NF) and SU (NF)/SO (NF). All possible explicit-breaking sources parametrized by spurions transforming in the fundamental and in the two-index representations of the flavor symmetry are included. While our general framework can be applied to any model of strong dynamics, we specialize to composite-Higgs models, where the main explicit breaking sources are a current mass, the gauging of flavor symmetries, and the Yukawa couplings (for the top). For the top, we consider both bilinear couplings and linear ones à la partial compositeness. Our templates provide a basis for lattice calculations in specific models. As a special example, we consider the SU (4 )/Sp (4 )≅SO (6 )/SO (5 ) pattern which corresponds to the minimal fundamental composite-Higgs model. We further revisit issues related to the misalignment of the vacuum. In particular, we shed light on the physical properties of the singlet η , showing that it cannot develop a vacuum expectation value without explicit C P violation in the underlying theory.

Spin Chirality of Cu3 and V3 Nanomagnets. 1. Rotation Behavior of Vector Chirality, Scalar Chirality, and Magnetization in the Rotating Magnetic Field, Magnetochiral Correlations.

PubMed

Belinsky, Moisey I

2016-05-02

The rotation behavior of the vector chirality κ, scalar chirality χ, and magnetization M in the rotating magnetic field H1 is considered for the V3 and Cu3 nanomagnets, in which the Dzialoshinsky-Moriya coupling is active. The polar rotation of the field H1 of the given strength H1 results in the energy spectrum characterized by different vector and scalar chiralities in the ground and excited states. The magnetochiral correlations between the vector and scalar chiralities, energy, and magnetization in the rotating field were considered. Under the uniform polar rotation of the field H1, the ground-state chirality vector κI performs sawtooth oscillations and the magnetization vector MI performs the sawtooth oscillating rotation that is accompanied by the correlated transformation of the scalar chirality χI. This demonstrates the magnetochiral effect of the joint rotation behavior and simultaneous frustrations of the spin chiralities and magnetization in the rotating field, which are governed by the correlation between the chiralities and magnetization.

Enhanced Chiral Discriminatory van der Waals Interactions Mediated by Chiral Surfaces

NASA Astrophysics Data System (ADS)

Barcellona, Pablo; Safari, Hassan; Salam, A.; Buhmann, Stefan Yoshi

2017-05-01

We predict a discriminatory interaction between a chiral molecule and an achiral molecule which is mediated by a chiral body. To achieve this, we generalize the van der Waals interaction potential between two ground-state molecules with electric, magnetic, and chiral response to nontrivial environments. The force is evaluated using second-order perturbation theory with an effective Hamiltonian. Chiral media enhance or reduce the free interaction via many-body interactions, making it possible to measure the chiral contributions to the van der Waals force with current technology. The van der Waals interaction is discriminatory with respect to enantiomers of different handedness and could be used to separate enantiomers. We also suggest a specific geometric configuration where the electric contribution to the van der Waals interaction is zero, making the chiral component the dominant effect.

An analytic approach to sunset diagrams in chiral perturbation theory: Theory and practice

NASA Astrophysics Data System (ADS)

Ananthanarayan, B.; Bijnens, Johan; Ghosh, Shayan; Hebbar, Aditya

2016-12-01

We demonstrate the use of several code implementations of the Mellin-Barnes method available in the public domain to derive analytic expressions for the sunset diagrams that arise in the two-loop contribution to the pion mass and decay constant in three-flavoured chiral perturbation theory. We also provide results for all possible two mass configurations of the sunset integral, and derive a new one-dimensional integral representation for the one mass sunset integral with arbitrary external momentum. Thoroughly annotated Mathematica notebooks are provided as ancillary files in the Electronic Supplementary Material to this paper, which may serve as pedagogical supplements to the methods described in this paper.

How the axial anomaly controls flavor mixing among mesons

NASA Astrophysics Data System (ADS)

Giacosa, Francesco; Koenigstein, Adrian; Pisarski, Robert D.

2018-05-01

It is well known that, because of the axial anomaly in QCD, mesons with JP=0- are close to S U (3 )V eigenstates; the η'(958 ) meson is largely a singlet, and the η meson an octet. In contrast, states with JP=1- are flavor diagonal; e.g., the ϕ (1020 ) is almost pure s ¯s . Using effective Lagrangians, we show how this generalizes to states with higher spin, assuming that they can be classified according to the unbroken chiral symmetry of Gfl=S U (3 )L×S U (3 )R. We construct effective Lagrangians from terms invariant under Gfl and introduce the concept of hetero- and homochiral multiplets. Because of the axial anomaly, only terms invariant under the Z (3 )A subgroup of the axial U (1 )A enter. For heterochiral multiplets, which begin with that including the η and η'(958 ), there are Z (3 )A invariant terms with low mass dimension which cause states to mix according to S U (3 )V flavor. For homochiral multiplets, which begin with that including the ϕ (1020 ), there are no Z (3 )A invariant terms with low mass dimension, and so states are diagonal in flavor. In this way, we predict the flavor mixing for the heterochiral multiplet with spin 1 as well as for hetero- and homochiral multiplets with spin 2 and spin 3.

Proton polarisability contribution to the Lamb shift in muonic hydrogen at fourth order in chiral perturbation theory

NASA Astrophysics Data System (ADS)

Birse, M. C.; McGovern, J. A.

2012-09-01

We calculate the amplitude T1 for forward doubly virtual Compton scattering in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the γ N Δ form factor. This provides a model-independent expression for the amplitude in the low-momentum region, which is the dominant one for its contribution to the Lamb shift. It allows us to significantly reduce the theoretical uncertainty in the proton polarisability contributions to the Lamb shift in muonic hydrogen. We also stress the importance of consistency between the definitions of the Born and structure parts of the amplitude. Our result leaves no room for any effect large enough to explain the discrepancy between proton charge radii as determined from muonic and normal hydrogen.

Stable Pentaquarks from Strange Chiral Multiplets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silas Beane

2004-12-01

The assumption of strong diquark correlations in the QCD spectrum suggests flavor multiplets of hadrons that are degenerate in the chiral limit. Generally it would be unnatural for there to be degeneracy in the hadron spectrum that is not protected by a QCD symmetry. Here we show--for pentaquarks constructed from diquarks--that these degeneracies can be naturally protected by the full chiral symmetry of QCD. The resulting chiral multiplet structure recovers the ideally-mixed pentaquark mass spectrum of the diquark model, and interestingly, requires that the axial couplings of the pentaquarks to states outside the degenerate multiplets vanish in the chiral limit.more » This result suggests that if these hadrons exist, they are stable in the chiral limit and therefore have widths that scale as the fourth power of the kaon mass over the chiral symmetry breaking scale. Natural-size widths are of order a few MeV.« less

Chiral Anomalous Dispersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadofyev, Andrey; Sen, Srimoyee

The linearized Einstein equation describing graviton propagation through a chiral medium appears to be helicity dependent. We analyze features of the corresponding spectrum in a collision-less regime above a flat background. In the long wave-length limit, circularly polarized metric perturbations travel with a helicity dependent group velocity that can turn negative giving rise to a new type of an anomalous dispersion. We further show that this chiral anomalous dispersion is a general feature of polarized modes propagating through chiral plasmas extending our result to the electromagnetic sector.

Chiral Anomalous Dispersion

DOE PAGES

Sadofyev, Andrey; Sen, Srimoyee

2018-02-16

The linearized Einstein equation describing graviton propagation through a chiral medium appears to be helicity dependent. We analyze features of the corresponding spectrum in a collision-less regime above a flat background. In the long wave-length limit, circularly polarized metric perturbations travel with a helicity dependent group velocity that can turn negative giving rise to a new type of an anomalous dispersion. We further show that this chiral anomalous dispersion is a general feature of polarized modes propagating through chiral plasmas extending our result to the electromagnetic sector.

Parametrization of a nonlocal chiral quark model in the instantaneous three-flavor case. Basic formulas and tables

NASA Astrophysics Data System (ADS)

Grigorian, H.

2007-05-01

We describe the basic formulation of the parametrization scheme for the instantaneous nonlocal chiral quark model in the three-flavor case. We choose to discuss the Gaussian, Lorentzian-type, Woods-Saxon, and sharp cutoff (NJL) functional forms of the momentum dependence for the form factor of the separable interaction. The four parameters, light and strange quark masses and coupling strength (G S) and range of the interaction (Λ), have been fixed by the same phenomenological inputs: pion and kaon masses and the pion decay constant and light quark mass in vacuum. The Woods-Saxon and Lorentzian-type form factors are suitable for an interpolation between sharp cutoff and soft momentum dependence. Results are tabulated for applications in models of hadron structure and quark matter at finite temperatures and chemical potentials, where separable models have been proven successfully.

Broken SU(3) x SU(3) x SU(3) x SU(3) Symmetry

DOE R&D Accomplishments Database

Freund, P. G. O.; Nambu, Y.

1964-10-01

We argue that the "Eight-fold Way" version of the SU(3) symmetry should be extended to a product of up to four separate and badly broken SU(3) groups, including the gamma{sub 5} type SU(3) symmetry. A hierarchy of subgroups (or subalgebras) are considered within this framework, and two candidates are found to be interesting in view of experimental evidence. Main features of the theory are: 1) the baryons belong to a nonet; 2) there is an octet of axial vector gauge mesons in addition to one or two octets of vector mesons; 3) pseudoscalar and scalar mesons exist as "incomplete" multiplets arising from spontaneous breakdown of symmetry.

Model of flavor unity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J.E.

1980-12-15

An SU(7) model is presented toward a flavor unification for known particles. The t quark is not a partner of the b quark. There are three types of neutrinos and several: so far unobserved: light detectable particles (masses <300 GeV): a doubly charged lepton T/sup - -/, a Q=-4/3 quark x, and a Q=5/3 quark y. An intermediate mass scale is a necessity and there is no problem of magnetic monopoles.

Intersecting branes, Higgs sector, and chirality from N = 4 SYM with soft SUSY breaking

NASA Astrophysics Data System (ADS)

Sperling, Marcus; Steinacker, Harold C.

2018-04-01

We consider SU( N ) N = 4 super Yang-Mills with cubic and quadratic soft SUSY breaking potential, such that the global SU(4) R is broken to SU(3) or further. As shown recently, this set-up supports a rich set of non-trivial vacua with the geometry of self-intersecting SU(3) branes in 6 extra dimensions. The zero modes on these branes can be interpreted as 3 generations of bosonic and chiral fermionic strings connecting the branes at their intersections. Here, we uncover a large class of exact solutions consisting of branes connected by Higgs condensates, leading to Yukawa couplings between the chiral fermionic zero modes. Under certain decoupling conditions, the backreaction of the Higgs on the branes vanishes exactly. The resulting physics is that of a spontaneously broken chiral gauge theory on branes with fluxes. In particular, we identify combined brane plus Higgs configurations which lead to gauge fields that couple to chiral fermions at low energy. This turns out to be quite close to the Standard Model and its constructions via branes in string theory. As a by-product, we construct a G 2-brane solution corresponding to a squashed fuzzy coadjoint orbit of G 2.

Broken SU(3) antidecuplet for {Theta}{sup +} and {Xi}{sub 3/2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakvasa, Sandip; Suzuki, Mahiko

2004-05-05

If the narrow exotic baryon resonances {Theta}{sup +}(1540) and {Xi}{sub 3/2} are members of the J{sup P} = 1/2{sup +} antidecuplet with N*(1710), the octet-antidecuplet mixing is required not only by the mass spectrum but also by the decay pattern of N*(1710). This casts doubt on validity of the {Theta}{sup +} mass prediction by the chiral soliton model. While all pieces of the existing experimental information point to a small octet-decuplet mixing, the magnitude of mixing required by the mass spectrum is not consistent with the value needed to account for the hadronic decay rates. The discrepancy is not resolvedmore » even after the large experimental uncertainty is taken into consideration. We fail to find an alternative SU(3) assignment even with different spin-parity assignment. When we extend the analysis to mixing with a higher SU(3) multiplet, we find one experimentally testable scenario in the case of mixing with a 27-plet.« less

Axial charges of octet and decuplet baryons in a perturbative chiral quark model

NASA Astrophysics Data System (ADS)

Liu, X. Y.; Samart, D.; Khosonthongkee, K.; Limphirat, A.; Xu, K.; Yan, Y.

2018-05-01

Using the perturbative chiral quark model (PCQM), we investigate and predict in this work axial charges gAB of octet and decuplet N , Σ , Ξ , Δ , Σ*, and Ξ* baryons, considering both the ground and excited states in the quark propagator. The PCQM predictions are in good agreement with the experimental data, lattice-QCD values, and other approaches. In addition, the study reveals that the meson cloud is influential in the PCQM, contributing around 30% to the total values of gAB, and the meson cloud contribution to gAB stems mainly from the diagrams with the ground-state quark propagator while the excited intermediate quark states reduce gAB by 10-20%.

QCD with two light dynamical chirally improved quarks: Mesons

NASA Astrophysics Data System (ADS)

Engel, Georg P.; Lang, C. B.; Limmer, Markus; Mohler, Daniel; Schäfer, Andreas

2012-02-01

We present results for the spectrum of light and strange mesons on configurations with two flavors of mass-degenerate Chirally Improved sea quarks. The calculations are performed on seven ensembles of lattice size 163×32 at three different gauge couplings and with pion masses ranging from 250 to 600 MeV. To reliably extract excited states, we use the variational method with an interpolator basis containing both Gaussian and derivative quark sources. Both conventional and exotic channels up to spin 2 are considered. Strange quarks are treated within the partially quenched approximation. For kaons we investigate the mixing of interpolating fields corresponding to definite C-parity in the SU(3) limit. This enlarged basis allows for an improved determination of the low-lying kaon spectrum. In addition to masses we also extract the ratio of the pseudoscalar decay constants of the kaon and pion and obtain FK/Fπ=1.215(41). The results presented here include some ensembles from previous publications and the corresponding results supersede the previously published values.

Centre vortex removal restores chiral symmetry

NASA Astrophysics Data System (ADS)

Trewartha, Daniel; Kamleh, Waseem; Leinweber, Derek B.

2017-12-01

The influence of centre vortices on dynamical chiral symmetry breaking is investigated through the light hadron spectrum on the lattice. Recent studies of the quark propagator and other quantities have provided evidence that centre vortices are the fundamental objects underpinning dynamical chiral symmetry breaking in {SU}(3) gauge theory. For the first time, we use the chiral overlap fermion action to study the low-lying hadron spectrum on lattice ensembles consisting of Monte Carlo, vortex-removed, and vortex-projected gauge fields. We find that gauge field configurations consisting solely of smoothed centre vortices are capable of reproducing all the salient features of the hadron spectrum, including dynamical chiral symmetry breaking. The hadron spectrum on vortex-removed fields shows clear signals of chiral symmetry restoration at light values of the bare quark mass, while at heavy masses the spectrum is consistent with a theory of weakly interacting constituent quarks.

Diastereoselective synthesis of chiral 1,3-cyclohexadienals

PubMed Central

de la Granja, Ángela P.; Capitán, M. Carmen; Moro, R. F.; Marcos, Isidro S.; Garrido, Narciso M.; Sanz, Francisca; Calle, Emilio

2018-01-01

A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potential photoprotective chiral 1,3-cyclohexadienals and extra extended conjugation compounds in a simple manner. PMID:29438416

Diastereoselective synthesis of chiral 1,3-cyclohexadienals.

PubMed

Urosa, Aitor; Tobal, Ignacio E; de la Granja, Ángela P; Capitán, M Carmen; Moro, R F; Marcos, Isidro S; Garrido, Narciso M; Sanz, Francisca; Calle, Emilio; Díez, David

2018-01-01

A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potential photoprotective chiral 1,3-cyclohexadienals and extra extended conjugation compounds in a simple manner.

Anatomy of the chiral magnetic effect in and out of equilibrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kharzeev, Dmitri; Stephanov, Mikhail; Yee, Ho-Ung

Here, we identify a new contribution to the chiral magnetic conductivity at finite frequencies—the magnetization current. This allows us to quantitatively reproduce the known field-theoretic time-dependent (AC) chiral magnetic response in terms of kinetic theory. We also evaluate the corresponding AC chiral magnetic conductivity in two-flavor QCD plasma at weak coupling. The magnetization current results from the spin response of chiral quasiparticles to magnetic field, and is thus proportional to the quasiparticle’s g -factor. Furthemrore, in condensed matter systems, where the chiral quasiparticles are emergent and the g -factor can significantly differ from 2, this opens up the possibility ofmore » tuning the AC chiral magnetic response.« less

Anatomy of the chiral magnetic effect in and out of equilibrium

DOE PAGES

Kharzeev, Dmitri; Stephanov, Mikhail; Yee, Ho-Ung

2017-03-28

Here, we identify a new contribution to the chiral magnetic conductivity at finite frequencies—the magnetization current. This allows us to quantitatively reproduce the known field-theoretic time-dependent (AC) chiral magnetic response in terms of kinetic theory. We also evaluate the corresponding AC chiral magnetic conductivity in two-flavor QCD plasma at weak coupling. The magnetization current results from the spin response of chiral quasiparticles to magnetic field, and is thus proportional to the quasiparticle’s g -factor. Furthemrore, in condensed matter systems, where the chiral quasiparticles are emergent and the g -factor can significantly differ from 2, this opens up the possibility ofmore » tuning the AC chiral magnetic response.« less

Centre vortex removal restores chiral symmetry

DOE PAGES

Trewartha, Daniel; Kamleh, Waseem; Leinweber, Derek B.

2017-11-15

The influence of centre vortices on dynamical chiral symmetry breaking is investigated through the light hadron spectrum on the lattice. Recent studies of the quark propagator and other quantities have provided evidence that centre vortices are the fundamental objects underpinning dynamical chiral symmetry breaking in SU(3) gauge theory. For the first time, we use the chiral overlap fermion action to study the low-lying hadron spectrum on lattice ensembles consisting of Monte Carlo, vortex-removed, and vortex-projected gauge fields. We find that gauge field configurations consisting solely of smoothed centre vortices are capable of reproducing all the salient features of the hadronmore » spectrum, including dynamical chiral symmetry breaking. In conclusion, the hadron spectrum on vortex-removed fields shows clear signals of chiral symmetry restoration at light values of the bare quark mass, while at heavy masses the spectrum is consistent with a theory of weakly-interacting constituent quarks.« less

Chiral corrections to the Adler-Weisberger sum rule

NASA Astrophysics Data System (ADS)

Beane, Silas R.; Klco, Natalie

2016-12-01

The Adler-Weisberger sum rule for the nucleon axial-vector charge, gA , offers a unique signature of chiral symmetry and its breaking in QCD. Its derivation relies on both algebraic aspects of chiral symmetry, which guarantee the convergence of the sum rule, and dynamical aspects of chiral symmetry breaking—as exploited using chiral perturbation theory—which allow the rigorous inclusion of explicit chiral symmetry breaking effects due to light-quark masses. The original derivations obtained the sum rule in the chiral limit and, without the benefit of chiral perturbation theory, made various attempts at extrapolating to nonvanishing pion masses. In this paper, the leading, universal, chiral corrections to the chiral-limit sum rule are obtained. Using PDG data, a recent parametrization of the pion-nucleon total cross sections in the resonance region given by the SAID group, as well as recent Roy-Steiner equation determinations of subthreshold amplitudes, threshold parameters, and correlated low-energy constants, the Adler-Weisberger sum rule is confronted with experimental data. With uncertainty estimates associated with the cross-section parametrization, the Goldberger-Treimann discrepancy, and the truncation of the sum rule at O (Mπ4) in the chiral expansion, this work finds gA=1.248 ±0.010 ±0.007 ±0.013 .

Complex Langevin simulation of chiral symmetry restoration at finite baryonic density

NASA Astrophysics Data System (ADS)

Ilgenfritz, Ernst-Michael

1986-12-01

A recently proposed effective SU(3) spin model with chiral order parameter is studied by means of the complex Langevin equation. A first-order chiral symmetry restoring and deconfining transition is observed at sufficiently low temperature at finite baryonic density. Permanent address: Sektion Physik, Karl-Marx Universität, DDR-7010 Leipzig, German Democratic Republic.

Extended investigation of the twelve-flavor β-function

NASA Astrophysics Data System (ADS)

Fodor, Zoltán; Holland, Kieran; Kuti, Julius; Nógrádi, Dániel; Wong, Chik Him

2018-04-01

We report new results from high precision analysis of an important BSM gauge theory with twelve massless fermion flavors in the fundamental representation of the SU(3) color gauge group. The range of the renormalized gauge coupling is extended from our earlier work [1] to probe the existence of an infrared fixed point (IRFP) in the β-function reported at two different locations, originally in [2] and at a new location in [3]. We find no evidence for the IRFP of the β-function in the extended range of the renormalized gauge coupling, in disagreement with [2,3]. New arguments to guard the existence of the IRFP remain unconvincing [4], including recent claims of an IRFP with ten massless fermion flavors [5,6] which we also rule out. Predictions of the recently completed 5-loop QCD β-function for general flavor number are discussed in this context.

XYZ-SU3 breakings from Laplace sum rules at higher orders

NASA Astrophysics Data System (ADS)

Albuquerque, R.; Narison, S.; Rabetiarivony, D.; Randriamanatrika, G.

2018-06-01

We present new compact integrated expressions of SU3 breaking corrections to QCD spectral functions of heavy-light molecules and four-quark XY Z-like states at lowest order (LO) of perturbative (PT) QCD and up to d = 8 condensates of the Operator Product Expansion (OPE). Including next-to-next-to-leading order (N2LO) PT corrections in the chiral limit and next-to-leading order (NLO) SU3 PT corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results for the XY Z-like masses and decay constants from QCD spectral sum rules (QSSR). Systematic errors are estimated from a geometric growth of the higher order PT corrections and from some partially known d = 8 nonperturbative contributions. Our optimal results, based on stability criteria, are summarized in Tables 18-21 while the 0++ and 1++ channels are compared with some existing LO results in Table 22. One can note that, in most channels, the SU3 corrections on the meson masses are tiny: ≤ 10% (respectively ≤ 3%) for the c (respectively b)-quark channel but can be large for the couplings ( ≤ 20%). Within the lowest dimension currents, most of the 0++ and 1++ states are below the physical thresholds while our predictions cannot discriminate a molecule from a four-quark state. A comparison with the masses of some experimental candidates indicates that the 0++ X(4500) might have a large D¯s0∗D s0∗ molecule component while an interpretation of the 0++ candidates as four-quark ground states is not supported by our findings. The 1++ X(4147) and X(4273) are compatible with the D¯s∗D s, D¯s0∗D s1 molecules and/or with the axial-vector Ac four-quark ground state. Our results for the 0‑±, 1‑± and for different beauty states can be tested in the future data. Finally, we revisit our previous estimates1 for the D¯0∗D 0∗ and D¯0∗D 1 and present new results for the D¯1D1.

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory

NASA Astrophysics Data System (ADS)

Chair, Noureddine

2014-02-01

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott's conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory.

Single-flavor CSL phase in compact stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaschke, David; Bogoliubov Laboratory for Theoretical Physics, JINR, 141980 Dubna; Sandin, Fredrik

2008-08-29

We suggest a scenario where the three light quark flavors are sequentially deconfined under increasing pressure in cold asymmetric nuclear matter as, e.g., in neutron stars. The basis for our analysis is a chiral quark matter model of Nambu-Jona-Lasinio (NJL) type with diquark pairing in the spin-1 single flavor (CSL), spin-0 two flavor (2SC) and three flavor (CFL) channels. We find that nucleon dissociation sets in at about the saturation density, n{sub 0}, when the down-quark Fermi sea is populated (d-quark dripline) due to the flavor asymmetry induced by {beta}-equilibrium and charge neutrality. At about 3n{sub 0} u-quarks appear andmore » a two-flavor color superconducting (2SC) phase is formed. The s-quark Fermi sea is populated only at still higher baryon density, when the quark chemical potential is of the order of the dynamically generated strange quark mass. We construct two different hybrid equations of state (EoS) using the Dirac-Brueckner Hartree-Fock (DBHF) approach and the EoS by Shen et al. in the nuclear matter sector. The corresponding hybrid star sequences have maximum masses of, respectively, 2.1 and 2.0 M{sub {center_dot}}. Two- and three-flavor quark-matter phases exist only in gravitationally unstable hybrid star solutions in the DBHF case, while the Shen-based EoS produce stable configurations with a 2SC phase component in the core of massive stars. Nucleon dissociation due to d-quark drip at the crust-core boundary fulfills basic criteria for a deep crustal heating process which is required to explain superbusts as well as cooling of X-ray transients.« less

A highly predictive A 4 flavor 3-3-1 model with radiative inverse seesaw mechanism

NASA Astrophysics Data System (ADS)

Cárcamo Hernández, A. E.; Long, H. N.

2018-04-01

We build a highly predictive 3-3-1 model, where the field content is extended by including several SU(3) L scalar singlets and six right handed Majorana neutrinos. In our model the {SU}{(3)}C× {SU}{(3)}L× U{(1)}X gauge symmetry is supplemented by the {A}4× {Z}4× {Z}6× {Z}16× {Z}16{\\prime } discrete group, which allows to get a very good description of the low energy fermion flavor data. In the model under consideration, the {A}4× {Z}4× {Z}6× {Z}16× {Z}16{\\prime } discrete group is broken at very high energy scale down to the preserved Z 2 discrete symmetry, thus generating the observed pattern of SM fermion masses and mixing angles and allowing the implementation of the loop level inverse seesaw mechanism for the generation of the light active neutrino masses, respectively. The obtained values for the physical observables in the quark sector agree with the experimental data, whereas those ones for the lepton sector also do, only for the case of inverted neutrino mass spectrum. The normal neutrino mass hierarchy scenario of the model is ruled out by the neutrino oscillation experimental data. We find an effective Majorana neutrino mass parameter of neutrinoless double beta decay of m ee = 46.9 meV, a leptonic Dirac CP violating phase of -81.37° and a Jarlskog invariant of about 10-2 for the inverted neutrino mass hierarchy. The preserved Z 2 symmetry allows for a stable scalar dark matter candidate.

Vectorlike chiral fourth family to explain muon anomalies

NASA Astrophysics Data System (ADS)

Raby, Stuart; Trautner, Andreas

2018-05-01

The Standard Model (SM) is amended by one generation of quarks and leptons which are vectorlike (VL) under the SM gauge group but chiral with respect to a new U(1 ) 3 -4 gauge symmetry. We show that this model can simultaneously explain the deviation of the muon g -2 as well as the observed anomalies in b →s μ+μ- transitions without conflicting with the data on Higgs decays, lepton flavor violation, or Bs-B¯s mixing. The model is string theory motivated and Grand Unified Theory compatible, i.e. UV complete, and fits the data predicting VL quarks, leptons, and a massive Z' at the TeV scale, as well as τ →3 μ and τ →μ γ within reach of future experiments. The Higgs couplings to SM generations are automatically aligned in flavor space.

Ω _c excited states within a SU(6)_{lsf}× HQSS model

NASA Astrophysics Data System (ADS)

Nieves, J.; Pavao, R.; Tolos, L.

2018-02-01

We have reviewed the renormalization procedure used in the unitarized coupled-channel model of Romanets et al. (Phys Rev D 85:114032, 2012), and its impact in the C=1, S=- 2, and I=0 sector, where five Ω _c^{(*)} states have been recently observed by the LHCb Collaboration. The meson-baryon interactions used in the model are consistent with both chiral and heavy-quark spin symmetries, and lead to a successful description of the observed lowest-lying odd parity resonances Λ _c(2595) and Λ _c(2625), and Λ _b(5912) and Λ _b(5920) resonances. We show that some (probably at least three) of the states observed by LHCb will also have odd parity and J=1/2 or J=3/2, belonging two of them to the same SU(6)_{light {-}spin {-}flavor}× HQSS multiplets as the latter charmed and beauty Λ baryons.

Quark structure of chiral solitons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dmitri Diakonov

2004-05-01

There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ''chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ''soliton'', however, with computable relativistic corrections andmore » additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.« less

Symmetry Transition Preserving Chirality in QCD: A Versatile Random Matrix Model

NASA Astrophysics Data System (ADS)

Kanazawa, Takuya; Kieburg, Mario

2018-06-01

We consider a random matrix model which interpolates between the chiral Gaussian unitary ensemble and the Gaussian unitary ensemble while preserving chiral symmetry. This ensemble describes flavor symmetry breaking for staggered fermions in 3D QCD as well as in 4D QCD at high temperature or in 3D QCD at a finite isospin chemical potential. Our model is an Osborn-type two-matrix model which is equivalent to the elliptic ensemble but we consider the singular value statistics rather than the complex eigenvalue statistics. We report on exact results for the partition function and the microscopic level density of the Dirac operator in the ɛ regime of QCD. We compare these analytical results with Monte Carlo simulations of the matrix model.

Chiral Dynamics 2006

NASA Astrophysics Data System (ADS)

Ahmed, Mohammad W.; Gao, Haiyan; Weller, Henry R.; Holstein, Barry

2007-10-01

pt. A. Plenary session. Opening remarks: experimental tests of chiral symmetry breaking / A. M. Bernstein. [Double pie symbols] scattering / H. Leutwyler. Chiral effective field theory in a [Triangle]-resonance region / V. Pascalutsa. Some recent developments in chiral perturbation theory / Ulf-G. Mei ner. Chiral extrapolation and nucleon structure from the lattice / R.D. Young. Recent results from HAPPEX / R. Michaels. Chiral symmetries and low energy searches for new physics / M.J. Ramsey-Musolf. Kaon physics: recent experimental progress / M. Moulson. Status of the Cabibbo angle / V. Cirigliano. Lattice QCD and nucleon spin structure / J.W. Negele. Spin sum rules and polarizabilities: results from Jefferson lab / J-P Chen. Compton scattering and nucleon polarisabilities / Judith A. McGovern. Virtual compton scattering at MIT-bates / R. Miskimen. Physics results from the BLAST detector at the BATES accelerator / R.P. Redwine. The [Pie sympbol]NN system, recent progress / C. Hanhart. Application of chiral nuclear forces to light nuclei / A. Nogga. New results on few-body experiments at low energy / Y. Nagai. Few-body lattice calculations / M.J. Savage. Research opportunities at the upgraded HI?S facility / H.R. Weller -- pt. B. Goldstone boson dynamics. Working group summary: Goldstone Boson dynamics / G. Colangelo and S. Giovannella. Recent results on radiative Kaon decays from NA48 and NA48/2 / S.G. López. Cusps in K-->3 [Pie symbol] decays / B. Kubis. Recent KTeV results on radiative Kaon decays / M.C. Ronquest. The [Double pie symbols] scattering amplitude / J.R. Peláez. Determination of the Regge parameters in the [Double pie symbols] scattering amplitude / I. Caprini. e+e- Hadronic cross section measurement at DA[symbol]NE with the KLOE detector / P. Beltrame. Measurement of the form factors of e+e- -->2([Pie symbol]+[Pie symbol]-), pp and the resonant parameters of the heavy charmonia at BES / H. Hu. Measurement of e+e- multihadronic cross section below 4

Three flavor Nambu-Jona-Lasinio model with Polyakov loop and competition with nuclear matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciminale, M.; Ippolito, N. D.; Nardulli, G.

2008-03-01

We study the phase diagram of the three flavor Polyakov-Nambu-Jona-Lasinio (PNJL) model and, in particular, the interplay between chiral symmetry restoration and deconfinement crossover. We compute chiral condensates, quark densities, and the Polyakov loop at several values of temperature and chemical potential. Moreover we investigate on the role of the Polyakov loop dynamics in the transition from nuclear matter to quark matter.

The twelve-flavor β-function and dilaton tests of the sextet scalar

NASA Astrophysics Data System (ADS)

Fodor, Zoltan; Holland, Kieran; Kuti, Julius; Nogradi, Daniel; Him Wong, Chik

2018-03-01

We discuss near-conformal gauge theories beyond the standard model (BSM) where interesting results on the twelve-flavor β-function of massless fermions in the fundamental representation of the SU(3) color gauge group and dilaton tests of the light scalar with two massless fermions in the two-index symmetric tensor (sextet) representation can be viewed as parts of the same BSM paradigm under investigation. The clear trend in the decreasing size of β-functions at fixed renormalized gauge coupling is interpreted as a first indicator how the conformal window (CW) is approached in correlation with emergent near-conformal light scalars. BSM model building close to the CW will be influenced by differing expectations on the properties of the emergent light 0++ scalar either as a σ-particle of chiral symmetry breaking (ΧS B), or as a dilaton of scale symmetry breaking. The twelve-flavor β-function emerges as closest to the CW, perhaps near-conformal, or perhaps with an infrared fixed point (IRFP) at some unexplored strong coupling inside the CW. It is premature to speculate on dilaton properties of the twelveflavor model since the near-conformal realization remains an open question. However, it is interesting and important to investigate dilaton tests of the light sextet scalar whose β-function is closest to the CW in the symmetry breaking phase and emerges as the leading candidate for dilaton tests of the light scalar. We report results from high precision analysis of the twelve-flavor β-function [1] refuting its published IRFP [2, 3]. We present our objections to recent claims [4, 5] for non-universal behavior of staggered fermions used in our analysis. We also report our first analysis of dilaton tests of the light 0++ scalar in the sextet model and comment on related post-conference developments. The dilaton test is the main thrust of this conference contribution including presentation #405 on the nf = 12 β-function and presentation #260 on dilaton tests of the

Bootstrapping N=2 chiral correlators

NASA Astrophysics Data System (ADS)

Lemos, Madalena; Liendo, Pedro

2016-01-01

We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

Sequential deconfinement of quark flavors in neutron stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaschke, D.; Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, RU-141980 Dubna; Sandin, F.

2009-12-15

A scenario is suggested in which the three light quark flavors are sequentially deconfined under increasing pressure in cold asymmetric nuclear matter as found, for example, in neutron stars. The basis for this analysis is a chiral quark matter model of Nambu-Jona-Lasinio (NJL) type with diquark pairing in the spin-1 single-flavor, spin-0 two-flavor, and three-flavor channels. Nucleon dissociation sets in at about the saturation density, n{sub 0}, when the down-quark Fermi sea is populated (d-quark drip line) because of the flavor asymmetry induced by {beta} equilibrium and charge neutrality. At about 3n{sub 0}, u-quarks appear and a two-flavor color superconductingmore » (2SC) phase is formed. The s-quark Fermi sea is populated only at still higher baryon density, when the quark chemical potential is of the order of the dynamically generated strange quark mass. Two different hybrid equations of state (EOSs) are constructed using the Dirac-Brueckner Hartree-Fock (DBHF) approach and the EOS of Shen et al.[H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi, Nucl. Phys. A637, 435 (1998)] in the nuclear matter sector. The corresponding hybrid star sequences have maximum masses of 2.1 and 2.0 M{sub {center_dot}}, respectively. Two- and three-flavor quark-matter phases exist only in gravitationally unstable hybrid star solutions in the DBHF case, whereas the Shen-based EOSs produce stable configurations with a 2SC phase component in the core of massive stars. Nucleon dissociation via d-quark drip could act as a deep crustal heating process, which apparently is required to explain superbursts and cooling of x-ray transients.« less

Baryon-baryon interactions and spin-flavor symmetry from lattice quantum chromodynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagman, Michael L.; Winter, Frank; Chang, Emmanuel

Lattice quantum chromodynamics is used to constrain the interactions of two octet baryons at the SU(3) flavor-symmetric point, with quark masses that are heavier than those in nature (equal to that of the physical strange quark mass and corresponding to a pion mass ofmore » $$\\approx 806~\\tt{MeV}$$). Specifically, the S-wave scattering phase shifts of two-baryon systems at low energies are obtained with the application of L\\"uscher's formalism, mapping the energy eigenvalues of two interacting baryons in a finite volume to the two-particle scattering amplitudes below the relevant inelastic thresholds. The values of the leading-order low-energy scattering parameters in the irreducible representations of SU(3) are consistent with an approximate SU(6) spin-flavor symmetry in the nuclear and hypernuclear forces that is predicted in the large-$$N_c$$ limit of QCD. The two distinct SU(6)-invariant interactions between two baryons are constrained at this value of the quark masses, and their values indicate an approximate accidental SU(16) symmetry. The SU(3) irreducible representations containing the $$NN~({^1}S_0)$$, $$NN~({^3}S_1)$$ and $$\\frac{1}{\\sqrt{2}}(\\Xi^0n+\\Xi^-p)~({^3}S_1)$$ channels unambiguously exhibit a single bound state, while the irreducible representation containing the $$\\Sigma^+ p~({^3}S_1)$$ channel exhibits a state that is consistent with either a bound state or a scattering state close to threshold. These results are in agreement with the previous conclusions of the NPLQCD collaboration regarding the existence of two-nucleon bound states at this value of the quark masses.« less

Baryon-baryon interactions and spin-flavor symmetry from lattice quantum chromodynamics

DOE PAGES

Wagman, Michael L.; Winter, Frank; Chang, Emmanuel; ...

2017-12-28

Lattice quantum chromodynamics is used to constrain the interactions of two octet baryons at the SU(3) flavor-symmetric point, with quark masses that are heavier than those in nature (equal to that of the physical strange quark mass and corresponding to a pion mass ofmore » $$\\approx 806~\\tt{MeV}$$). Specifically, the S-wave scattering phase shifts of two-baryon systems at low energies are obtained with the application of L\\"uscher's formalism, mapping the energy eigenvalues of two interacting baryons in a finite volume to the two-particle scattering amplitudes below the relevant inelastic thresholds. The values of the leading-order low-energy scattering parameters in the irreducible representations of SU(3) are consistent with an approximate SU(6) spin-flavor symmetry in the nuclear and hypernuclear forces that is predicted in the large-$$N_c$$ limit of QCD. The two distinct SU(6)-invariant interactions between two baryons are constrained at this value of the quark masses, and their values indicate an approximate accidental SU(16) symmetry. The SU(3) irreducible representations containing the $$NN~({^1}S_0)$$, $$NN~({^3}S_1)$$ and $$\\frac{1}{\\sqrt{2}}(\\Xi^0n+\\Xi^-p)~({^3}S_1)$$ channels unambiguously exhibit a single bound state, while the irreducible representation containing the $$\\Sigma^+ p~({^3}S_1)$$ channel exhibits a state that is consistent with either a bound state or a scattering state close to threshold. These results are in agreement with the previous conclusions of the NPLQCD collaboration regarding the existence of two-nucleon bound states at this value of the quark masses.« less

Nuclear electromagnetic charge and current operators in Chiral EFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Girlanda, Luca; Marcucci, Laura Elisa; Pastore, Saori

2013-08-01

We describe our method for deriving the nuclear electromagnetic charge and current operators in chiral perturbation theory, based on time-ordered perturbation theory. We then discuss possible strategies for fixing the relevant low-energy constants, from the magnetic moments of the deuteron and of the trinucleons, and from the radiative np capture cross sections, and identify a scheme which, partly relying on {Delta} resonance saturation, leads to a reasonable pattern of convergence of the chiral expansion.

Lattice spin models for non-Abelian chiral spin liquids

DOE PAGES

Lecheminant, P.; Tsvelik, A. M.

2017-04-26

Here, we suggest a class of two-dimensional lattice spin Hamiltonians describing non-Abelian SU(2) chiral spin liquids—spin analogs of fractional non-Abelian quantum Hall states—with gapped bulk and gapless chiral edge excitations described by the SU(2) n Wess-Zumino-Novikov-Witten conformal field theory. The models are constructed from an array of generalized spin-n/2 ladders with multi-spin-exchange interactions which are coupled by isolated spins. Such models allow a controllable analytic treatment starting from the one-dimensional limit and are characterized by a bulk gap and non-Abelian SU(2) n gapless edge excitations.

Duality, marginal perturbations, and gauging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henningson, M.; Nappi, C.R.

1993-07-15

We study duality transformations for two-dimensional [sigma] models with Abelian chiral isometries and prove that generic such transformations are equivalent to integrated marginal perturbations by bilinears in the chiral currents, thus confirming a recent conjecture by Hassan and Sen formulated in the context of Wess-Zumino-Witten models. Specific duality transformations instead give rise to coset models plus free bosons.

Elastic pp-bar and pp scattering up to. sqrt. s = 546 GeV and the flavored perturbative Reggeon field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dash, J.W.; Jones, S.T.

We show that the perturbative Reggeon field theory (RFT) with flavoring corrections added reproduces the pp and pp-bar differential cross sections from Fermilab to the CERN SPS collider (Spp-bar S). This completes a long program of phenomenology which is now capable of providing a unified framework for soft hadronic scattering at current energies. Our scenario of data being influenced by finite scales at least up to ..sqrt..s = 546 GeV is compatible with the truly asymptotic limit being described by the critical RFT scaling laws.

Influence of flavor oscillations on neutrino beam instabilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendonça, J. T., E-mail: titomend@ist.utl.pt; Haas, F.; Bret, A.

2014-09-15

We consider the collective neutrino plasma interactions and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual interaction between neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.

Calculation of the {pi}{sup +}{Sigma}{sup +} and {pi}{sup +}{Xi}{sup 0} Scattering Lengths in Lattice QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Torok, Aaron

The {pi}{sup +}{Sigma}{sup +} and {pi}{sup +}{Xi}{sup 0} scattering lengths were calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks was used to perform the chiral extrapolations. To NNLO in the three-flavor chiral expansion, the kaon-baryon processes that were investigated show no signs of convergence. Using the two-flavor chiral expansion for extrapolation, the pion-hyperon scattering lengths are found to be a{sub {pi}}{sup +}{sub {Sigma}}{sup +} = -0.197{+-}0.017more » fm, and a{sub {pi}}{sup +}{sub {Xi}}{sup 0} = -0.098{+-}0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.« less

Lattice input on the inclusive flavor-breaking τ Vus puzzle

NASA Astrophysics Data System (ADS)

Maltman, Kim; Hudspith, Renwick; Lewis, Randy; Wolfe, Carl; Zanotti, James

2015-10-01

Recent versions of the standard approach to implementing the flavor-breaking finite-energy sum rule determination of Vus using spectral data obtained from hadronic tau decays produce values of Vus more than 3 sigma low relative to the expectations of 3-family unitarity. We revisit this problem, focusing on systematic issues in the treatment of OPE contributions, employing lattice data for the relevant flavor-breaking correlator combinination to help in understanding how to treat the slowly converging D = 2 series and investigate potential D > 4 non-perturbative contributions. The results, in combination with observations from additional flavor-breaking continuum sum rules, are shown to suggest an alternate implementation of the flavor-breaking sum rule approach. This alternate analysis approach is shown to produce significantly higher Vus than obtained using the assumptions of the conventional implementation, for reasons that will be explained in detail. We also show that, when this approach is implemented using new preliminary results for the tau K pi branching fractions, the Vus obtained is in excellent agreement with that obtained from recent analyses of Kell3 using lattice input for f+(0).

Unification of gauge, family, and flavor symmetries illustrated in gauged SU(12) models

DOE PAGES

Albright, Carl H.; Feger, Robert P.; Kephart, Thomas W.

2016-04-25

In this study, to explain quark and lepton masses and mixing angles, one has to extend the standard model, and the usual practice is to put the quarks and leptons into irreducible representations of discrete groups. We argue that discrete flavor symmetries (and their concomitant problems) can be avoided if we extend the gauge group. In the framework of SU(12) we give explicit examples of models having varying degrees of predictability obtained by scanning over groups and representations and identifying cases with operators contributing to mass and mixing matrices that need little fine- tuning of prefactors. Fitting with quark andmore » lepton masses run to the GUT scale and known mixing angles allows us to make predictions for the neutrino masses and hierarchy, the octant of the atmospheric mixing angle, leptonic CP violation, Majorana phases, and the effective mass observed in neutrinoless double beta decay.« less

The use of diacetyl (2,3-butanedione) and related flavoring substances as flavorings added to foods-Workplace safety issues.

PubMed

Hallagan, John B

2017-08-01

In 2001, staff of the National Institute of Occupational Safety and Health (NIOSH) identified diacetyl (2,3-butanedione) as a "marker" of exposure in a microwave popcorn manufacturing facility in which workers developed severe respiratory illness. Subsequent investigations identified additional workers in food and flavor manufacturing facilities also with severe respiratory illness. The flavor industry, NIOSH, and federal and state regulators conducted significant programs to address workplace safety concerns related to the manufacture of flavors and foods containing added flavors. These programs, initiated in 2001, continue today. Key to the success of these programs is understanding what flavors added to foods are and how they are manufactured, how they are incorporated into foods, the specific characteristics of diacetyl and related flavoring substances, and what actions may be taken to assure the safest workplaces possible. Copyright © 2017 Elsevier B.V. All rights reserved.

Enantiodifferentiation of whisky and cognac lactones using gas chromatography with different cyclodextrin chiral stationary phases.

PubMed

Schmarr, Hans-Georg; Mathes, Maximilian; Wall, Kristina; Metzner, Frank; Fraefel, Marius

2017-09-22

The chiral lactone 5-butyl-4-methyloxolan-2-one or 5-butyl-4-methyldihydro-2(3H)-furanone, often named whisky lactone, is found in oak wood, then contributing to the appreciated flavor of beverages stored in such wooden barrels. Its next higher homologue is named cognac lactone (5-pentyl-4-methyloxolan-2-one or 5-pentyl-4-methyldihydro-2(3H)-furanone), however is much less known, probably due to its minor concentration level. In order to study the direct enantioseparation of both lactones by gas chromatography on chiral stationary phases, individual enantiomers, particularly for cognac lactone were made available. This was achieved by baker's yeast reduction of synthesized ethyl 3-methyl-4-oxononanoate or, after hydrolysis, of the corresponding 4-ketoacid, that gave access to individual enantiomers of cognac lactone. Good enantioseparation was achieved for both whisky and cognac lactone with high values for the chiral resolution with 6-O-tert. butyl dimethylsilyl-2,3-dialkylated or 6-O-tert. butyl dimethylsilyl-2,3-diacylated cyclodextrin derivatives as chiral selectors. The influence of the nature and position of derivatization of the cyclodextrin moiety revealed a strong impact on the chiral recognition mechanism, as the investigated alkylated derivatives heptakis-(2,6-di-O-iso-pentyl-3-O-allyl)-β-cyclodextrin and octakis-(2,3-di-O-pentyl-6-O-methyl)-γ-cyclodextrin did not provide any or only minor chiral selectivity for the two lactones. Copyright © 2017 Elsevier B.V. All rights reserved.

Triggering collective oscillations by three-flavor effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasgupta, Basudeb; Raffelt, Georg G.; Tamborra, Irene

2010-04-01

Collective flavor transformations in supernovae, caused by neutrino-neutrino interactions, are essentially a two-flavor phenomenon driven by the atmospheric mass difference and the small mixing angle {theta}{sub 13}. In the two-flavor approximation, the initial evolution depends logarithmically on {theta}{sub 13} and the system remains trapped in an unstable fixed point for {theta}{sub 13}=0. However, any effect breaking exact {nu}{sub {mu}-{nu}{tau}}equivalence triggers the conversion. Such three-flavor perturbations include radiative corrections to weak interactions, small differences between the {nu}{sub {mu}}and {nu}{sub {tau}}fluxes, or nonstandard interactions. Therefore, extremely small values of {theta}{sub 13} are in practice equivalent, the fate of the system depending onlymore » on the neutrino spectra and their mass ordering.« less

Nonlinear chiral plasma transport in rotating coordinates

NASA Astrophysics Data System (ADS)

Dayi, Ömer F.; Kilinçarslan, Eda

2017-08-01

The nonlinear transport features of inhomogeneous chiral plasma in the presence of electromagnetic fields, in rotating coordinates are studied within the relaxation time approach. The chiral distribution functions up to second order in the electric field in rotating coordinates and the derivatives of chemical potentials are established by solving the Boltzmann transport equation. First, the vector and axial current densities in the weakly ionized chiral plasma for vanishing magnetic field are calculated. They involve the rotational analogues of the Hall effect as well as several new terms arising from the Coriolis and fictitious centrifugal forces. Then in the short relaxation time regime the angular velocity and electromagnetic fields are treated as perturbations. The current densities are obtained by retaining the terms up to second order in perturbations. The time evolution equations of the inhomogeneous chemical potentials are derived by demanding that collisions conserve the particle number densities.

Flavored dark matter beyond Minimal Flavor Violation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, Prateek; Blanke, Monika; Gemmler, Katrin

We study the interplay of flavor and dark matter phenomenology for models of flavored dark matter interacting with quarks. We allow an arbitrary flavor structure in the coupling of dark matter with quarks. This coupling is assumed to be the only new source of violation of the Standard Model flavor symmetry extended by a U(3) χ associated with the dark matter. We call this ansatz Dark Minimal Flavor Violation (DMFV) and highlight its various implications, including an unbroken discrete symmetry that can stabilize the dark matter. As an illustration we study a Dirac fermionic dark matter χ which transforms asmore » triplet under U(3) χ , and is a singlet under the Standard Model. The dark matter couples to right-handed down-type quarks via a colored scalar mediator Φ with a coupling λ. We identify a number of “flavor-safe” scenarios for the structure of λ which are beyond Minimal Flavor Violation. Also, for dark matter and collider phenomenology we focus on the well-motivated case of b-flavored dark matter. Furthermore, the combined flavor and dark matter constraints on the parameter space of λ turn out to be interesting intersections of the individual ones. LHC constraints on simplified models of squarks and sbottoms can be adapted to our case, and monojet searches can be relevant if the spectrum is compressed.« less

Flavored dark matter beyond Minimal Flavor Violation

DOE PAGES

Agrawal, Prateek; Blanke, Monika; Gemmler, Katrin

2014-10-13

We study the interplay of flavor and dark matter phenomenology for models of flavored dark matter interacting with quarks. We allow an arbitrary flavor structure in the coupling of dark matter with quarks. This coupling is assumed to be the only new source of violation of the Standard Model flavor symmetry extended by a U(3) χ associated with the dark matter. We call this ansatz Dark Minimal Flavor Violation (DMFV) and highlight its various implications, including an unbroken discrete symmetry that can stabilize the dark matter. As an illustration we study a Dirac fermionic dark matter χ which transforms asmore » triplet under U(3) χ , and is a singlet under the Standard Model. The dark matter couples to right-handed down-type quarks via a colored scalar mediator Φ with a coupling λ. We identify a number of “flavor-safe” scenarios for the structure of λ which are beyond Minimal Flavor Violation. Also, for dark matter and collider phenomenology we focus on the well-motivated case of b-flavored dark matter. Furthermore, the combined flavor and dark matter constraints on the parameter space of λ turn out to be interesting intersections of the individual ones. LHC constraints on simplified models of squarks and sbottoms can be adapted to our case, and monojet searches can be relevant if the spectrum is compressed.« less

Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes

PubMed Central

Allen, Joseph G.; Flanigan, Skye S.; LeBlanc, Mallory; Vallarino, Jose; MacNaughton, Piers; Stewart, James H.; Christiani, David C.

2015-01-01

Background: There are > 7,000 e-cigarette flavors currently marketed. Flavoring chemicals gained notoriety in the early 2000s when inhalation exposure of the flavoring chemical diacetyl was found to be associated with a disease that became known as “popcorn lung.” There has been limited research on flavoring chemicals in e-cigarettes. Objective: We aimed to determine if the flavoring chemical diacetyl and two other high-priority flavoring chemicals, 2,3-pentanedione and acetoin, are present in a convenience sample of flavored e-cigarettes. Methods: We selected 51 types of flavored e-cigarettes sold by leading e-cigarette brands and flavors we deemed were appealing to youth. E-cigarette contents were fully discharged and the air stream was captured and analyzed for total mass of diacetyl, 2,3-pentanedione, and acetoin, according to OSHA method 1012. Results: At least one flavoring chemical was detected in 47 of 51 unique flavors tested. Diacetyl was detected above the laboratory limit of detection in 39 of the 51 flavors tested, ranging from below the limit of quantification to 239 μg/e-cigarette. 2,3-Pentanedione and acetoin were detected in 23 and 46 of the 51 flavors tested at concentrations up to 64 and 529 μg/e-cigarette, respectively. Conclusion: Because of the associations between diacetyl and bronchiolitis obliterans and other severe respiratory diseases observed in workers, urgent action is recommended to further evaluate this potentially widespread exposure via flavored e-cigarettes. Citation: Allen JG, Flanigan SS, LeBlanc M, Vallarino J, MacNaughton P, Stewart JH, Christiani DC. 2016. Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, candy-, and cocktail-flavored e-cigarettes. Environ Health Perspect 124:733–739; http://dx.doi.org/10.1289/ehp.1510185 PMID:26642857

Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes.

PubMed

Allen, Joseph G; Flanigan, Skye S; LeBlanc, Mallory; Vallarino, Jose; MacNaughton, Piers; Stewart, James H; Christiani, David C

2016-06-01

There are > 7,000 e-cigarette flavors currently marketed. Flavoring chemicals gained notoriety in the early 2000s when inhalation exposure of the flavoring chemical diacetyl was found to be associated with a disease that became known as "popcorn lung." There has been limited research on flavoring chemicals in e-cigarettes. We aimed to determine if the flavoring chemical diacetyl and two other high-priority flavoring chemicals, 2,3-pentanedione and acetoin, are present in a convenience sample of flavored e-cigarettes. We selected 51 types of flavored e-cigarettes sold by leading e-cigarette brands and flavors we deemed were appealing to youth. E-cigarette contents were fully discharged and the air stream was captured and analyzed for total mass of diacetyl, 2,3-pentanedione, and acetoin, according to OSHA method 1012. At least one flavoring chemical was detected in 47 of 51 unique flavors tested. Diacetyl was detected above the laboratory limit of detection in 39 of the 51 flavors tested, ranging from below the limit of quantification to 239 μg/e-cigarette. 2,3-Pentanedione and acetoin were detected in 23 and 46 of the 51 flavors tested at concentrations up to 64 and 529 μg/e-cigarette, respectively. Because of the associations between diacetyl and bronchiolitis obliterans and other severe respiratory diseases observed in workers, urgent action is recommended to further evaluate this potentially widespread exposure via flavored e-cigarettes. Allen JG, Flanigan SS, LeBlanc M, Vallarino J, MacNaughton P, Stewart JH, Christiani DC. 2016. Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, candy-, and cocktail-flavored e-cigarettes. Environ Health Perspect 124:733-739; http://dx.doi.org/10.1289/ehp.1510185.

Nucleon Structure Functions from a Chiral Soliton

NASA Astrophysics Data System (ADS)

Weigel, Herbert

1998-10-01

In an attempt to merge the parton model description of deep inelastic scattering with the phenomenologically successful picture of baryons as chiral solitons we study nucleon structure functions in the Nambu--Jona--Lasinio (NJL) chiral soliton model(R. Alkofer, H. Reinhardt and H. Weigel, Phys. Rep. 265) (1996) 139.. We compute the unpolarized structure function for electron--nucleon scattering which enters the Gottfried sum rule, S_G. The model calculation not only explains the observed deviation from the historical value S_G=1/3 but also reproduces the gross features of the exerimental data when accounting for projection and Q^2--evolution(H. Weigel, L. Gamberg and H. Reinhardt, Mod. Phys. Lett. A11) (1996) 3021; Phys. Lett. B399 (1997) 287.. The latter operation further serves to determine the low--momentum scale, Q_0^2, of the model. Subsequently we turn to the polarized structure functions g_1(x,Q^2) and g_2(x,Q^2)(H. Weigel, L. Gamberg and H. Reinhardt, Phys. Rev. D55) (1997) 6910.. These are particularly interesting in the present model because chiral soliton models nicely account for the smallness of the first moment of g_1(x,Q^2). In addition we report on the calculation(L. Gamberg, H. Reinhardt and H. Weigel, Phys. Rev. D58) (1998) 054014. of the chiral odd quark distributions and the corresponding structure functions h_T(x,Q^2) and h_L(x,Q^2). At the low model scale, Q_0^2, we find that the leading twist effective quark distributions, f_1^(q)(x,Q_0^2), g_1^(q)(x,Q_0^2) and h_T^(q)(x,Q_0^2) satisfy Soffer's inequality for both quark flavors q=u,d. The Q^2 evolution of the twist--2 contributions is performed according to the standard GLAP formalism while the twist--three pieces, \\overlineg_2(x) and \\overlineh_L(x), are evolved according to the large NC scheme. Finally we explain the generalization of chiral soliton models to three flavors and discuss the strange quark contribution to g1 as an example(box[t]15cm)O. Schröder, H. Reinhardt and H. Weigel

Macdonald index and chiral algebra

NASA Astrophysics Data System (ADS)

Song, Jaewon

2017-08-01

For any 4d N = 2 SCFT, there is a subsector described by a 2d chiral algebra. The vacuum character of the chiral algebra reproduces the Schur index of the corresponding 4d theory. The Macdonald index counts the same set of operators as the Schur index, but the former has one more fugacity than the latter. We conjecture a prescription to obtain the Macdonald index from the chiral algebra. The vacuum module admits a filtration, from which we construct an associated graded vector space. From this grading, we conjecture a notion of refined character for the vacuum module of a chiral algebra, which reproduces the Macdonald index. We test this prescription for the Argyres-Douglas theories of type ( A 1 , A 2 n ) and ( A 1 , D 2 n+1) where the chiral algebras are given by Virasoro and \\widehat{su}(2) affine Kac-Moody algebra. When the chiral algebra has more than one family of generators, our prescription requires a knowledge of the generators from the 4d.

Macdonald index and chiral algebra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Jaewon

For any 4dN = 2 SCFT, there is a subsector described by a 2d chiral algebra. The vacuum character of the chiral algebra reproduces the Schur index of the corresponding 4d theory. The Macdonald index counts the same set of operators as the Schur index, but the former has one more fugacity than the latter. Here, we conjecture a prescription to obtain the Macdonald index from the chiral algebra. The vacuum module admits a filtration, from which we construct an associated graded vector space. From this grading, we conjecture a notion of refined character for the vacuum module of a chiral algebra, which reproduces the Macdonald index. We test this prescription for the Argyres-Douglas theories of type (A 1, A 2n) and (A 1, D 2n+1) where the chiral algebras are given by Virasoro andmore » $$ˆ\\atop{su}$$(2) affine Kac-Moody algebra. When the chiral algebra has more than one family of generators, our prescription requires a knowledge of the generators from the 4d.« less

Macdonald index and chiral algebra

DOE PAGES

Song, Jaewon

2017-08-10

For any 4dN = 2 SCFT, there is a subsector described by a 2d chiral algebra. The vacuum character of the chiral algebra reproduces the Schur index of the corresponding 4d theory. The Macdonald index counts the same set of operators as the Schur index, but the former has one more fugacity than the latter. Here, we conjecture a prescription to obtain the Macdonald index from the chiral algebra. The vacuum module admits a filtration, from which we construct an associated graded vector space. From this grading, we conjecture a notion of refined character for the vacuum module of a chiral algebra, which reproduces the Macdonald index. We test this prescription for the Argyres-Douglas theories of type (A 1, A 2n) and (A 1, D 2n+1) where the chiral algebras are given by Virasoro andmore » $$ˆ\\atop{su}$$(2) affine Kac-Moody algebra. When the chiral algebra has more than one family of generators, our prescription requires a knowledge of the generators from the 4d.« less

The anomalous U(1)_{anom} symmetry and flavors from an SU(5) × SU(5)' GUT in Z_{12-I} orbifold compactification

NASA Astrophysics Data System (ADS)

Kim, Jihn E.; Kyae, Bumseok; Nam, Soonkeon

2017-12-01

In string compactifications, frequently the anomalous U(1) gauge symmetry appears which belongs to E_8 × E_8' of the heterotic string. This anomalous U(1) gauge boson obtains mass at the compactification scale (≈ 10^{18 } {GeV}) by absorbing one pseudoscalar (corresponding to the model-independent axion) from the second rank antisymmetric tensor field B_{MN}. Below the compactification scale a global symmetry U(1)_{anom} results whose charge Q_anom is the original gauge U(1) charge. This is the most natural global symmetry, realizing the "invisible" axion. This global symmetry U(1)_{anom} is suitable for a flavor symmetry. In the simplest compactification model with the flipped SU(5) grand unification, all the low energy parameters are calculated in terms of the vacuum expectation values of the standard model singlets.

Nucleon Structure from 2+1 Flavor Domain Wall QCD at Nearly Physical Pion Mass

NASA Astrophysics Data System (ADS)

Ohta, Shigemi

2011-05-01

The RBC and UKQCD collaborations have been investigating hadron physics in numerical lattice quantum chromodynamics (QCD) with (2+1) flavors of dynamical domain wall fermions (DWF) quarks that preserves continuum-like chiral and flavor symmetries. The strange quark mass is adjusted to physical value via reweighting and degenerate up and down quark masses are set as light as possible. In a recent study of nucleon structure we found a strong dependence on pion mass and lattice spatial extent in isovector axialvector-current form factors. This is likely the first credible evidence for the pion cloud surrounding nucleon. Here we report the status of nucleon structure calculations with a new (2+1)-flavor dynamical DWF ensembles with much lighter pion mass of 180 and 250 MeV and a much larger lattice spatial exent of 4.6 fm. A combination of the Iwasaki and dislocation-suppressing-determinant-ratio (I+DSDR) gauge action and DWF fermion action allows us to generate these ensembles at cutoff of about 1.4 GeV while keeping the residual breaking of chiral symmetry sufficiently small. Nucleon source Gaussian smearing has been optimized. Preliminary nucleon mass estimates are 0.98 and 1.05 GeV.

Pion-nucleon scattering: from chiral perturbation theory to Roy-Steiner equations

NASA Astrophysics Data System (ADS)

Kubis, Bastian; Hoferichter, Martin; de Elvira, Jacobo Ruiz; Meißner, Ulf-G.

2016-11-01

Ever since Weinberg's seminal predictions of the pion-nucleon scattering amplitudes at threshold, this process has been of central interest for the study of chiral dynamics involving nucleons. The scattering lengths or the pion-nucleon σ-term are fundamental quantities characterizing the explicit breaking of chiral symmetry by means of the light quark masses. On the other hand, pion-nucleon dynamics also strongly affects the long-range part of nucleon-nucleon potentials, and hence has a far-reaching impact on nuclear physics. We discuss the fruitful combination of dispersion-theoretical methods, in the form of Roy-Steiner equations, with chiral dynamics to determine pion-nucleon scattering amplitudes at low energies with high precision.*

Spectroscopy of SU(4) composite Higgs theory with two distinct fermion representations

NASA Astrophysics Data System (ADS)

Ayyar, Venkitesh; DeGrand, Thomas; Golterman, Maarten; Hackett, Daniel C.; Jay, William I.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin

2018-04-01

We have simulated the SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. Such theories arise naturally in the context of composite Higgs models that include a partially composite top quark. We describe the low-lying meson spectrum of the theory and fit the pseudoscalar masses and decay constants to chiral perturbation theory. We infer as well the mass and decay constant of the Goldstone boson corresponding to the nonanomalous U(1) symmetry of the model. Our results are broadly consistent with large-Nc scaling and vector-meson dominance.

Multi-hadron-state contamination in nucleon observables from chiral perturbation theory

NASA Astrophysics Data System (ADS)

Bär, Oliver

2018-03-01

Multi-particle states with additional pions are expected to be a non-negligible source of the excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory (ChPT) can be employed to calculate the contamination due to two-particle nucleon-pion states in various nucleon observables. Results to leading order are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions: the average quark momentum fraction, the helicity and the transversity moment. Taking into account experimental and phenomenological results for the charges and moments the impact of the nucleon-pionstates on lattice estimates for these observables can be estimated. The nucleon-pion-state contribution leads to an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5-10% level for source-sink separations of about 2 fm. Existing lattice data is not in conflict with the ChPT predictions, but the comparison suggests that significantly larger source-sink separations are needed to compute the charges and moments with few-percent precision. Talk given at the 35th International Symposium on Lattice Field Theory, 18 - 24 June 2017, Granada, Spain.

Meson properties and phase diagrams in a SU(3) nonlocal PNJL model with lattice-QCD-inspired form factors

NASA Astrophysics Data System (ADS)

Carlomagno, J. P.

2018-05-01

We study the features of a nonlocal SU(3) Polyakov-Nambu-Jona-Lasinio model that includes wave-function renormalization. Model parameters are determined from vacuum phenomenology considering lattice-QCD-inspired nonlocal form factors. Within this framework, we analyze the properties of light scalar and pseudoscalar mesons at finite temperature and chemical potential determining characteristics of deconfinement and chiral restoration transitions.

Flavor symmetry breaking in lattice QCD with a mixed action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Oliver; Golterman, Maarten; Shamir, Yigal

2011-03-01

We study the phase structure of mixed-action QCD with two Wilson sea quarks and any number of chiral valence quarks (and ghosts), starting from the chiral Lagrangian. A priori the effective theory allows for a rich phase structure, including a phase with a condensate made of sea and valence quarks. In such a phase, mass eigenstates would become admixtures of sea and valence fields, and pure-sea correlation functions would depend on the parameters of the valence sector, in contradiction with the actual setup of mixed-action simulations. Using that the spectrum of the chiral Dirac operator has a gap for nonzeromore » quark mass we prove that spontaneous symmetry breaking of the flavor symmetries can only occur within the sea sector. This rules out a mixed condensate and implies restrictions on the low-energy constants of the effective theory.« less

Chiral symmetry breaking and the spin content of the ρ and ρ‧ mesons

NASA Astrophysics Data System (ADS)

Glozman, L. Ya.; Lang, C. B.; Limmer, M.

2011-11-01

Using interpolators with different SU(2)L × SU(2)R transformation properties we study the chiral symmetry and spin contents of the ρ and ρ‧ mesons in lattice simulations with dynamical quarks. A ratio of couplings of the qbarγi τq and qbarσ0i τq interpolators to a given meson state at different resolution scales tells one about the degree of chiral symmetry breaking in the meson wave function at these scales. Using a Gaussian gauge invariant smearing of the quark fields in the interpolators, we are able to extract the chiral content of mesons up to the infrared resolution of ∼ 1 fm. In the ground state ρ meson the chiral symmetry is strongly broken with comparable contributions of both the (0 , 1) + (1 , 0) and (1 / 2 , 1 / 2) b chiral representations with the former being the leading contribution. In contrast, in the ρ‧ meson the degree of chiral symmetry breaking is manifestly smaller and the leading representation is (1 / 2 , 1 / 2) b. Using a unitary transformation from the chiral basis to the LJ2S+1 basis, we are able to define and measure the angular momentum content of mesons in the rest frame. This definition is different from the traditional one which uses parton distributions in the infinite momentum frame. The ρ meson is practically a 3S1 state with no obvious trace of a "spin crisis". The ρ‧ meson has a sizeable contribution of the 3D1 wave, which implies that the ρ‧ meson cannot be considered as a pure radial excitation of the ρ meson.

A Clifford algebra approach to chiral symmetry breaking and fermion mass hierarchies

NASA Astrophysics Data System (ADS)

Lu, Wei

2017-09-01

We propose a Clifford algebra approach to chiral symmetry breaking and fermion mass hierarchies in the context of composite Higgs bosons. Standard model fermions are represented by algebraic spinors of six-dimensional binary Clifford algebra, while ternary Clifford algebra-related flavor projection operators control allowable flavor-mixing interactions. There are three composite electroweak Higgs bosons resulted from top quark, tau neutrino, and tau lepton condensations. Each of the three condensations gives rise to masses of four different fermions. The fermion mass hierarchies within these three groups are determined by four-fermion condensations, which break two global chiral symmetries. The four-fermion condensations induce axion-like pseudo-Nambu-Goldstone bosons and can be dark matter candidates. In addition to the 125 GeV Higgs boson observed at the Large Hadron Collider, we anticipate detection of tau neutrino composite Higgs boson via the charm quark decay channel.

QCD thermodynamics with two flavors at Nt=6

NASA Astrophysics Data System (ADS)

Bernard, Claude; Ogilvie, Michael C.; Degrand, Thomas A.; Detar, Carleton; Gottlieb, Steven; Krasnitz, Alex; Sugar, R. L.; Toussaint, D.

1992-05-01

The first results of numerical simulations of quantum chromodynamics on the Intel iPSC/860 parallel processor are presented. We performed calculations with two flavors of Kogut-Susskind quarks at Nt=6 with masses of 0.15T and 0.075T (0.025 and 0.0125 in lattice units) in order to locate the crossover from the low-temperature regime of ordinary hadronic matter to the high-temperature chirally symmetric regime. As with other recent two-flavor simulations, these calculations are insufficient to distinguish between a rapid crossover and a true phase transition. The phase transition is either absent or feeble at this quark mass. An improved estimate of the crossover temperature in physical units is given and results are presented for the hadronic screening lengths in both the high- and low-temperature regimes.

Dark revelations of the [SU(3)]3 and [SU(3)]4 gauge extensions of the standard model

NASA Astrophysics Data System (ADS)

Kownacki, Corey; Ma, Ernest; Pollard, Nicholas; Popov, Oleg; Zakeri, Mohammadreza

2018-02-01

Two theoretically well-motivated gauge extensions of the standard model are SU(3)C × SU(3)L × SU(3)R and SU(3)q × SU(3)L × SU(3)l × SU(3)R, where SU(3)q is the same as SU(3)C and SU(3)l is its color leptonic counterpart. Each has three variations, according to how SU(3)R is broken. It is shown here for the first time that a built-in dark U(1)D gauge symmetry exists in all six versions. However, the corresponding symmetry breaking pattern does not reduce properly to that of the standard model, unless an additional Z2‧ symmetry is defined, so that U(1)D ×Z2‧ is broken to Z2 dark parity. The available dark matter candidates in each case include fermions, scalars, as well as vector gauge bosons. This work points to the possible unity of matter with dark matter, the origin of which may not be ad hoc.

Lepton flavor violating decays of B and K mesons in models with extended gauge group

NASA Astrophysics Data System (ADS)

Fayyazuddin; Aslam, Muhammad Jamil; Lu, Cai-Dian

2018-05-01

Lepton flavor violating (LFV) decays are forbidden in the Standard Model (SM) and to explore them one has to go beyond it. The flavor changing neutral current induced lepton flavor conserving and LFV decays of K and B mesons is discussed in the gauge group G = SU(2)L × U(1)Y1 × SU(2)X. The lepto-quark Xμ±2/3 corresponding to gauge group SU(2)X allows the quark-lepton transitions and hence giving a framework to construct the effective Lagrangian for the LFV decays. The mass of lepto-quark mX provides a scale at which the gauge group G is broken to the SM gauge group. Using the most stringent experimental limit ℬ(KL0 → μ∓e±) < 1.7 × 10‑12, the upper bound on the effective coupling constant GX GF2 < 1.1 × 10‑10 is obtained for certain pairing of lepton and quark generations in the representation (2,2¯) of the group G. Later, the effective Lagrangian for the LFV meson decays for the gauge group G = [SU(2)L × SU(2)R × U(1)Y1‧] × SU(2)X is constructed. Using ℬ(K‑→ π‑νν¯) = (1.7 ± 1.1) × 10‑10, the bound on the ratio of effective couplings is obtained to be GX GF2 < 10‑10. A number of decay modes are discussed which provide a promising area to test this model in the current and future particle physics experiments.

Switching chiral solitons for algebraic operation of topological quaternary digits

NASA Astrophysics Data System (ADS)

Kim, Tae-Hwan; Cheon, Sangmo; Yeom, Han Woong

2017-02-01

Chiral objects can be found throughout nature; in condensed matter chiral objects are often excited states protected by a system's topology. The use of chiral topological excitations to carry information has been demonstrated, where the information is robust against external perturbations. For instance, reading, writing, and transfer of binary information have been demonstrated with chiral topological excitations in magnetic systems, skyrmions, for spintronic devices. The next step is logic or algebraic operations of such topological bits. Here, we show experimentally the switching between chiral topological excitations or chiral solitons of different chirality in a one-dimensional electronic system with Z4 topological symmetry. We found that a fast-moving achiral soliton merges with chiral solitons to switch their handedness. This can lead to the realization of algebraic operation of Z4 topological charges. Chiral solitons could be a platform for storage and operation of robust topological multi-digit information.

Flavor structure of Λ baryons from lattice QCD: From strange to charm quarks

NASA Astrophysics Data System (ADS)

Gubler, Philipp; Takahashi, Toru T.; Oka, Makoto

2016-12-01

We study Λ baryons of spin-parity 1/2± with either a strange or charm valence quark in full 2 +1 flavor lattice QCD. Multiple S U (3 ) singlet and octet operators are employed to generate the desired single baryon states on the lattice. Via the variational method, the couplings of these states to the different operators provide information about the flavor structure of the Λ baryons. We make use of the gauge configurations of the PACS-CS Collaboration and chirally extrapolate the results for the masses and S U (3 ) flavor components to the physical point. We furthermore gradually change the hopping parameter of the heaviest quark from strange to charm to study how the properties of the Λ baryons evolve as a function of the heavy quark mass. It is found that the baryon energy levels increase almost linearly with the quark mass. Meanwhile, the flavor structure of most of the states remains stable, with the exception of the lowest 1/2- state, which changes from a flavor singlet Λ to a Λc state with singlet and octet components of comparable size. Finally, we discuss whether our findings can be interpreted with the help of a simple quark model and find that the negative-parity Λc states can be naturally explained as diquark excitations of the light u and d quarks. On the other hand, the quark-model picture does not appear to be adequate for the negative-parity Λ states, suggesting the importance of other degrees of freedom to describe them.

Investigation of the chiral antiferromagnetic Heisenberg model using projected entangled pair states

NASA Astrophysics Data System (ADS)

Poilblanc, Didier

2017-09-01

A simple spin-1/2 frustrated antiferromagnetic Heisenberg model (AFHM) on the square lattice—including chiral plaquette cyclic terms—was argued [A. E. B. Nielsen, G. Sierra, and J. I. Cirac, Nat. Commun. 4, 2864 (2013), 10.1038/ncomms3864] to host a bosonic Kalmeyer-Laughlin (KL) fractional quantum Hall ground state [V. Kalmeyer and R. B. Laughlin, Phys. Rev. Lett. 59, 2095 (1987), 10.1103/PhysRevLett.59.2095]. Here, we construct generic families of chiral projected entangled pair states (chiral PEPS) with low bond dimension (D =3 ,4 ,5 ) which, upon optimization, provide better variational energies than the KL Ansatz. The optimal D =3 PEPS exhibits chiral edge modes described by the Wess-Zumino-Witten SU(2) 1 model, as expected for the KL spin liquid. However, we find evidence that, in contrast to the KL state, the PEPS spin liquids have power-law dimer-dimer correlations and exhibit a gossamer long-range tail in the spin-spin correlations. We conjecture that these features are genuine to local chiral AFHM on bipartite lattices.

Chiral dynamics in the low-temperature phase of QCD

NASA Astrophysics Data System (ADS)

Brandt, Bastian B.; Francis, Anthony; Meyer, Harvey B.; Robaina, Daniel

2014-09-01

We investigate the low-temperature phase of QCD and the crossover region with two light flavors of quarks. The chiral expansion around the point (T,m=0) in the temperature vs quark-mass plane indicates that a sharp real-time excitation exists with the quantum numbers of the pion. An exact sum rule is derived for the thermal modification of the spectral function associated with the axial charge density; the (dominant) pion pole contribution obeys the sum rule. We determine the two parameters of the pion dispersion relation using lattice QCD simulations and test the applicability of the chiral expansion. The time-dependent correlators are also analyzed using the maximum entropy method, yielding consistent results. Finally, we test the predictions of the chiral expansion around the point (T=0,m=0) for the temperature dependence of static observables.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pisarski, Robert D.; Skokov, Vladimir V.

Previously, a matrix model of the region near the transition temperature, in the “semi”quark gluon plasma, was developed for the theory of SU(3) gluons without quarks. In this paper we develop a chiral matrix model applicable to QCD by including dynamical quarks with 2+1 flavors. This requires adding a nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y. Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. As is standard, the potential for the scalar fields is chosen to bemore » symmetric under the flavor symmetry of SU (3) L × SU(3) R × Z (3) A , except for a term linear in the current quark mass, m qk . In addition, at a nonzero temperature T it is necessary to add a new term, ~ m qk T 2 . The parameters of the gluon part of the matrix model are identical to those for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant and the masses of the pions, kaons, η , and η' . The temperature for the chiral crossover at T$χ$ = 155 MeV is determined by adjusting the Yukawa coupling y . We find reasonable agreement with the results of numerical simulations on the lattice for the pressure and related quantities. In the chiral limit, besides the divergence in the chiral susceptibility there is also a milder divergence in the susceptibility between the Polyakov loop and the chiral order parameter, with critical exponent β $-$ 1 . We compute derivatives with respect to a quark chemical potential to determine the susceptibilities for baryon number, the $χ$ 2n . Especially sensitive tests are provided by $χ$ 4 $-$ $χ$ 2 and by $χ$ 6 , which changes in sign about T$χ$ . In conclusion, the behavior of the susceptibilities in the chiral matrix model strongly suggests that as the temperature increases from T$χ$ , that the transition to

Instanton-dyon ensembles reproduce deconfinement and chiral restoration phase transitions

NASA Astrophysics Data System (ADS)

Shuryak, Edward

2018-03-01

Paradigm shift in gauge topology at finite temperatures, from the instantons to their constituents - instanton-dyons - has recently lead to studies of their ensembles and very significant advances. Like instantons, they have fermionic zero modes, and their collectivization at suffciently high density explains the chiral symmetry breaking transition. Unlike instantons, these objects have electric and magnetic charges. Simulations of the instanton-dyon ensembles have demonstrated that their back reaction on the Polyakov line modifies its potential and generates the deconfinement phase transition. For the Nc = 2 gauge theory the transition is second order, for QCD-like theory with Nc = 2 and two light quark flavors Nf = 2 both transitions are weak crossovers at happening at about the same condition. Introduction of quark-flavor-dependent periodicity phases (imaginary chemical potentials) leads to drastic changes in both transitions. In particulaly, in the so called Z(Nc) - QCD model the deconfinement transforms to strong first order transition, while the chiral condensate does not disappear at all. The talk will also cover more detailed studies of correlations between the dyons, effective eta' mass and other screening masses.

Broken S 3L×S 3R flavor symmetry and leptonic CP violation

NASA Astrophysics Data System (ADS)

Si, Zong-guo; Yang, Xing-hua; Zhou, Shun

2017-11-01

In the framework of the canonical seesaw model, we present a simple but viable scenario to explicitly break an S 3L×S 3R flavor symmetry in the leptonic sector. It turns out that the leptonic flavor mixing matrix is completely determined by the mass ratios of the charged leptons (i.e., m e/m μ and m μ/m τ) and those of light neutrinos (i.e., m 1/m 2 and m 2/m 3). The latest global-fit results of the three neutrino mixing angles {θ 12, θ 13, θ 23} and two neutrino mass-squared differences at the 3σ level are used to constrain the parameter space of {m 1/m 2,m 2/m 3}. The predictions for the mass spectrum and flavor mixing are highlighted: (1) the neutrino mass spectrum shows a hierarchical pattern and a normal ordering, e.g., m 1≈2.2 meV, m 2≈8.8 meV and m 3≈52.7 meV (2) only the first octant of θ 23 is allowed, namely, 41.8°≲θ 23≲43.3° (3) the Dirac CP-violating phase δ≈-22° deviates significantly from the maximal value -90°. All these predictions are ready to be tested in ongoing and forthcoming neutrino oscillation experiments. Moreover, we demonstrate that the cosmological matter-antimatter asymmetry can be explained via resonant leptogenesis, including the individual lepton-flavor effects. In our scenario, leptonic CP violation at low- and high-energy scales is closely connected. Supported by NNSFC (11325525), National Recruitment Program for Young Professionals and CAS Center for Excellence in Particle Physics (CCEPP)

Effects of flavor-symmetry violation from staggered fermion lattice simulations of graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giedt, Joel; Nayak, Saroj; Skinner, Andrew

2011-01-15

We analyze the effects of flavor splitting from staggered fermion lattice simulations of a low-energy effective theory for graphene. Both the unimproved action and the tadpole-improved action with a Naik term show significant flavor-symmetry breaking in the spectrum of the Dirac operator. Note that this is true even in the vicinity of the second-order phase transition point where it has been argued that the flavor-symmetry breaking should be small due to the continuum limit being approached. We show that at weaker couplings the flavor splitting is drastically reduced by stout link smearing, while this mechanism is ineffective at the strongermore » couplings relevant to suspended graphene. We also measure the average plaquette and describe how it calls for a reinterpretation of previous lattice Monte Carlo simulation results, due to tadpole improvement. After taking into account these effects, we conclude that previous lattice simulations are possibly indicative of an insulating phase, although the effective number of light flavors could be effectively less than two due to the flavor-splitting effects. If that is true, then simulations with truly chiral fermions (such as overlap fermions) are needed in order to settle the question.« less

The association between flavor labeling and flavor recall ability in children.

PubMed

Lumeng, Julie C; Zuckerman, Matthew D; Cardinal, Tiffany; Kaciroti, Niko

2005-09-01

This study sought to determine if the ability to label a flavor is associated with an improved ability to recall having tasted the flavor in preschool-aged children. A total of 120 3- to 6-year-old English-speaking children tasted and labeled 20 different flavors, blinded to color. Children's labels for the flavors were scored for consistency and accuracy. Recall for having tasted the flavor was tested. Both labeling ability and recall ability improved rapidly between the ages of 3 and 6 years in this cohort. Regression analysis indicated that independent of the child's age, consistent accurate labeling was positively associated with recall ability. Higher maternal education was an independent and marginal contributor to greater recall ability. The combination of consistent and accurate labeling, age, and maternal education accounted for 28% of the variance in flavor recall ability. Consistent but inaccurate labeling alone contributed little to the variance in flavor recall ability. We conclude from these findings that children's ability to recall having tasted a flavor develops rapidly during the preschool age range and that improved recall ability is associated with the ability to consistently and accurately label the flavor. We conclude that language mediates memory for flavors in young children.

Flavor Profile of Chinese Liquor Is Altered by Interactions of Intrinsic and Extrinsic Microbes

PubMed Central

Wu, Qun; Kong, Yu

2015-01-01

The flavor profile of Chinese liquor is the result of the metabolic activity of its microbial community. Given the importance of the microbial interaction, a novel way to control the liquor's flavor is by regulating the composition of the community. In this study, we efficiently improved the liquor's flavor by perturbing the intrinsic microbial metabolism with extrinsic microbes. We first constructed a basic microbial group (intrinsic) containing Saccharomyces cerevisiae, Wickerhamomyces anomalus, and Issatchenkia orientalis and added special flavor producers (extrinsic), Saccharomyces uvarum and Saccharomyces servazzii, to this intrinsic group. Upon the addition of the extrinsic microbes, the maximum specific growth rates of S. cerevisiae and I. orientalis increased from 6.19 to 43.28/day and from 1.15 to 14.32/day, respectively, but that of W. anomalus changed from 1.00 to 0.96/day. In addition, most volatile compounds known to be produced by the extrinsic strains were not produced. However, more esters, alcohols, and acids were produced by S. cerevisiae and I. orientalis. Six compounds were significantly different by random forest analysis after perturbation. Among them, increases in ethyl hexanoate, isobutanol, and 3-methylbutyric acid were correlated with S. cerevisiae and I. orientalis, and a decrease in geranyl acetone was correlated with W. anomalus. Variations in ethyl acetate and 2-phenylethanol might be due to the varied activity of W. anomalus and S. cerevisiae. This work showed the effect of the interaction between the intrinsic and extrinsic microbes on liquor flavor, which would be beneficial for improving the quality of Chinese liquor. PMID:26475111

Topological susceptibility in finite temperature (2 +1 )-flavor QCD using gradient flow

NASA Astrophysics Data System (ADS)

Taniguchi, Yusuke; Kanaya, Kazuyuki; Suzuki, Hiroshi; Umeda, Takashi; WHOT-QCD Collaboration

2017-03-01

We compute the topological charge and its susceptibility in finite temperature (2 +1 )-flavor QCD on the lattice applying a gradient flow method. With the Iwasaki gauge action and nonperturbatively O (a ) -improved Wilson quarks, we perform simulations on a fine lattice with a ≃0.07 fm at a heavy u , d quark mass with mπ/mρ≃0.63 , but approximately physical s quark mass with mηss/mϕ≃0.74 . In a temperature range from T ≃174 MeV (Nt=16 ) to 697 MeV (Nt=4 ), we study two topics on the topological susceptibility. One is a comparison of gluonic and fermionic definitions of the topological susceptibility. Because the two definitions are related by chiral Ward-Takahashi identities, their equivalence is not trivial for lattice quarks which violate the chiral symmetry explicitly at finite lattice spacings. The gradient flow method enables us to compute them without being bothered by the chiral violation. We find a good agreement between the two definitions with Wilson quarks. The other is a comparison with a prediction of the dilute instanton gas approximation, which is relevant in a study of axions as a candidate of the dark matter in the evolution of the Universe. We find that the topological susceptibility shows a decrease in T which is consistent with the predicted χt(T )∝(T /Tpc)-8 for three-flavor QCD even at low temperature Tpc

Nucleon sea in the effective chiral quark model

NASA Astrophysics Data System (ADS)

Ding, Yong; Xu, Rong-Guang; Ma, Bo-Qiang

2005-05-01

The asymmetries of both light-flavor antiquark d¯(x)-u¯(x) and strange-antistrange s(x)-s¯(x) distributions of the nucleon sea are considered with more details in the effective chiral quark model. We find that the asymmetric distribution of light-flavor antiquarks d¯(x)-u¯(x) matches the experimental data well and that the asymmetry of strange and antistrange distributions can bring about 60% 100% correction to the NuTeV anomaly of sin(2θw, which are 3 standard deviations from the world average value measured in other electroweak processes. The results on the correction to the NuTeV anomaly are insensitive to the inputs of the constituent quark distributions and the cutoff parameters. The ratios of d¯(x)/u¯(x) and s(x)/s¯(x) are also discussed, and it is found that the ratio s(x)/s¯(x) is compatible with the available experiments with an additional symmetric sea contribution being considered effectively.

Topology in the SU(Nf) chiral symmetry restored phase of unquenched QCD and axion cosmology

NASA Astrophysics Data System (ADS)

Azcoiti, Vicente

2018-03-01

The axion is one of the more interesting candidates to make the dark matter of the universe, and the axion potential plays a fundamental role in the determination of the dynamics of the axion field. Moreover, the way in which the U(1)A anomaly manifests itself in the chiral symmetry restored phase of QCD at high temperature could be tested when probing the QCD phase transition in relativistic heavy ion collisions. With these motivations, we investigate the physical consequences of the survival of the effects of the U(1)A anomaly in the chiral symmetric phase of QCD, and show that the free energy density is a singular function of the quark mass m, in the chiral limit, and that the σ and π susceptibilities diverge in this limit at any T ≥ Tc. We also show that the difference between the π and t;δ susceptibilities diverges in the chiral limit at any T ≥ Tc, a result that can be contrasted with the existing lattice calculations; and discuss on the generalization of these results to the Nf ≥ 3 model.

Flavored leptogenesis with quasidegenerate neutrinos in a broken cyclic symmetric model

NASA Astrophysics Data System (ADS)

Adhikary, Biswajit; Chakraborty, Mainak; Ghosal, Ambar

2016-06-01

Cyclic symmetry in the neutrino sector with the type-I seesaw mechanism in the mass basis of charged leptons and right chiral neutrinos (Ni R, i =e , μ , τ ) generates a twofold degenerate light neutrino and a threefold degenerate heavy neutrino mass spectrum. Consequently, such a scheme produces vanishing one light neutrino mass squared difference and lepton asymmetry. To circumvent such an unphysical outcome, we break cyclic symmetry in the diagonal right chiral neutrino mass term by a small breaking parameter. Nonzero mass squared differences and mixing angles are generated with the help of the small breaking parameter. The smallness of the breaking parameter opens up the possibility of resonant leptogenesis. Assuming complex Yukawa couplings, we derive generalized expressions with flavor-dependent C P asymmetry parameters (ɛiα ) which are valid for the quasidegenerate as well as hierarchical mass spectrum of right-handed neutrinos. Thereafter, we set up the chain of coupled Boltzmann equations (which are flavor dependent too) which have to be solved in order to get the final lepton asymmetries. Depending upon the temperature regime, the C P asymmetries and the Boltzmann equations may also be flavor independent. As our goal is to study the enhancement of C P asymmetry due to the quasidegeneracy of right-handed neutrinos, we select only the lowest allowed (by neutrino oscillation data) value of the breaking parameter (and other corresponding Lagrangian parameters) and estimate the baryon asymmetry parameter YB. The experimental constraint of YB introduces a bound on right-handed neutrino mass which remained unrestricted by neutrino oscillation data.

Molecular recognition in chiral smectic liquid crystals: the effect of core-core interactions and chirality transfer on polar order.

PubMed

Lemieux, Robert P

2007-12-01

This critical review focuses on the induction of polar order in smectic liquid crystal phases by dopants with axially chiral cores, and should be of interest to all practitioners of supramolecular chemistry. The variations in polarization power of these dopants with the core structure of the liquid crystal hosts is a manifestation of molecular recognition that reflects the nanosegregation of aromatic cores from paraffinic side-chains in smectic phases, and the collective effect of core-core interactions that enable the propagation of chiral perturbations.

Chiral EFT based nuclear forces: achievements and challenges

NASA Astrophysics Data System (ADS)

Machleidt, R.; Sammarruca, F.

2016-08-01

During the past two decades, chiral effective field theory has become a popular tool to derive nuclear forces from first principles. Two-nucleon interactions have been worked out up to sixth order of chiral perturbation theory and three-nucleon forces up to fifth order. Applications of some of these forces have been conducted in nuclear few- and many-body systems—with a certain degree of success. But in spite of these achievements, we are still faced with great challenges. Among them is the issue of a proper uncertainty quantification of predictions obtained when applying these forces in ab initio calculations of nuclear structure and reactions. A related problem is the order by order convergence of the chiral expansion. We start this review with a pedagogical introduction and then present the current status of the field of chiral nuclear forces. This is followed by a discussion of representative examples for the application of chiral two- and three-body forces in the nuclear many-body system including convergence issues.

Flavor Profile of Chinese Liquor Is Altered by Interactions of Intrinsic and Extrinsic Microbes.

PubMed

Wu, Qun; Kong, Yu; Xu, Yan

2016-01-15

The flavor profile of Chinese liquor is the result of the metabolic activity of its microbial community. Given the importance of the microbial interaction, a novel way to control the liquor's flavor is by regulating the composition of the community. In this study, we efficiently improved the liquor's flavor by perturbing the intrinsic microbial metabolism with extrinsic microbes. We first constructed a basic microbial group (intrinsic) containing Saccharomyces cerevisiae, Wickerhamomyces anomalus, and Issatchenkia orientalis and added special flavor producers (extrinsic), Saccharomyces uvarum and Saccharomyces servazzii, to this intrinsic group. Upon the addition of the extrinsic microbes, the maximum specific growth rates of S. cerevisiae and I. orientalis increased from 6.19 to 43.28/day and from 1.15 to 14.32/day, respectively, but that of W. anomalus changed from 1.00 to 0.96/day. In addition, most volatile compounds known to be produced by the extrinsic strains were not produced. However, more esters, alcohols, and acids were produced by S. cerevisiae and I. orientalis. Six compounds were significantly different by random forest analysis after perturbation. Among them, increases in ethyl hexanoate, isobutanol, and 3-methylbutyric acid were correlated with S. cerevisiae and I. orientalis, and a decrease in geranyl acetone was correlated with W. anomalus. Variations in ethyl acetate and 2-phenylethanol might be due to the varied activity of W. anomalus and S. cerevisiae. This work showed the effect of the interaction between the intrinsic and extrinsic microbes on liquor flavor, which would be beneficial for improving the quality of Chinese liquor. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Direct mass limits for chiral fourth-generation quarks in all mixing scenarios.

PubMed

Flacco, Christian J; Whiteson, Daniel; Tait, Tim M P; Bar-Shalom, Shaouly

2010-09-10

Present limits on chiral fourth-generation quark masses mb' and mt' are broadly generalized and strengthened by combining both t' and b' decays and considering a full range of t' and b' flavor-mixing scenarios with the lighter generations (to 1-‖V44‖2≈10(-13)). Various characteristic mass-splitting choices are considered. With mt'>mb' we find that CDF Collaboration limits on the b' mass vary by no more than 10%-20% with any choice of flavor mixing, while for the t' mass, we typically find stronger bounds, in some cases up to mt'>430  GeV. For mb'>mt', we find mb'>380-430  GeV, depending on the flavor mixing and the size of the mt'-mb' mass splitting.

The role of the S 3 GUT leptoquark in flavor universality and collider searches

NASA Astrophysics Data System (ADS)

Doršner, Ilja; Fajfer, Svjetlana; Faroughy, Darius A.; Košnik, Nejc

2017-10-01

We investigate the ability of the S 3 scalar leptoquark to address the recent hints of lepton universality violation in B meson decays. The S 3 leptoquark with quantum numbers (\\overline{3},3,1/3) naturally emerges in the context of an SU(5) GUT model without any conflict with the stringent limits from observed nucleon stability. Scalar leptoquark S 3 with left-handed couplings to 2nd and 3rd generations of charged leptons and down-type quarks seems well-suited to address both R K(∗) and R D(∗) . We quantify this suitability with numerical fits to a plethora of relevant flavor observables. The proposed SU(5) model calls for a second leptoquark state, i.e., \\tilde{R}_2 with quantum numbers ( 3 , 2 , 1 /6), if one is to generate gauge coupling unification and neutrino mass. We accordingly include it in our study to investigate \\tilde{R}_2 's ability to offset adverse effects of S 3 and thus improve a quality of numerical fits. A global fit of the leptoquark Yukawa couplings shows that large couplings of light S 3 to τ leptons are preferred. We furthermore identify B\\to {K}^{(\\ast )}\\overline{ν}ν as the most sensitive channel to probe the preferred region of parameter space. Large couplings of S 3 to τ leptons are finally confronted with the experimental searches for τ final states at the Large Hadron Collider. These searches comprise a study of decay products of the leptoquark pair production, as well as, and more importantly, an analysis of the high-mass ττ finalstates.

The qqqqq components and hidden flavor contributions to the baryon magnetic moments

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, C. S.; Li, Q. B.; Riska, D. O.

2006-11-15

The contributions from the qqqqq components to the magnetic moments of the octet as well as the {delta}{sup ++} and {omega}{sup -} decuplet baryons are calculated for the configurations that are expected to have the lowest energy if the hyperfine interaction depends on both spin and flavor. The contributions from the uu,dd, and the ss components are given separately. It is shown that addition of qqqqq admixtures to the ground state baryons can improve the overall description of the magnetic moments of the baryon octet and decuplet in the quark model without SU(3) flavor symmetry breaking, beyond that of themore » different constituent masses of the strange and light-flavor quarks. The explicit flavor (and spin) wave functions for all the possible configurations of the qqqqq components with light and strange qq pairs are given for the baryon octet and decuplet. Admixtures of {approx}10% of the qqqqq configuration where the flavor-spin symmetry is [4]{sub FS}[22]{sub F}[22]{sub S}, which is likely to have the lowest energy, in particular reduces the deviation from the empirical values of the magnetic moments {sigma}{sup -} and the {xi}{sup 0} compared with the static qqq quark model.« less

Model with a gauged lepton flavor SU(2) symmetry

NASA Astrophysics Data System (ADS)

Chiang, Cheng-Wei; Tsumura, Koji

2018-05-01

We propose a model having a gauged SU(2) symmetry associated with the second and third generations of leptons, dubbed SU(2) μτ , of which U{(1)}_{L_{μ }-L_{τ }} is an Abelian subgroup. In addition to the Standard Model fields, we introduce two types of scalar fields. One exotic scalar field is an SU(2) μτ doublet and SM singlet that develops a nonzero vacuum expectation value at presumably multi-TeV scale to completely break the SU(2) μτ symmetry, rendering three massive gauge bosons. At the same time, the other exotic scalar field, carrying electroweak as well as SU(2) μτ charges, is induced to have a nonzero vacuum expectation value as well and breaks mass degeneracy between the muon and tau. We examine how the new particles in the model contribute to the muon anomalous magnetic moment in the parameter space compliant with the Michel decays of tau.

The scalar and electromagnetic form factors of the nucleon in dispersively improved Chiral EFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcon, Jose Manuel

We present a method for calculating the nucleon form factors of G-parity-even operators. This method combines chiral effective field theory (χEFT) and dispersion theory. Through unitarity we factorize the imaginary part of the form factors into a perturbative part, calculable with χEFT, and a non-perturbative part, obtained through other methods. We consider the scalar and electromagnetic (EM) form factors of the nucleon. The results show an important improvement compared to standard chiral calculations, and can be used in analysis of the low-energy properties of the nucleon.

SU(2) with fundamental fermions and scalars

NASA Astrophysics Data System (ADS)

Hansen, Martin; Janowski, Tadeusz; Pica, Claudio; Toniato, Arianna

2018-03-01

We present preliminary results on the lattice simulation of an SU(2) gauge theory with two fermion flavors and one strongly interacting scalar field, all in the fundamental representation of SU(2). The motivation for this study comes from the recent proposal of "fundamental" partial compositeness models featuring strongly interacting scalar fields in addition to fermions. Here we describe the lattice setup for our study of this class of models and a first exploration of the lattice phase diagram. In particular we then investigate how the presence of a strongly coupled scalar field affects the properties of light meson resonances previously obtained for the SU(2) model. Preprint: CP3-Origins-2017-047 DNRF90

Pion-photon reactions and chiral dynamics in Primakoff processes at COMPASS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedrich, Jan Michael

2016-01-22

With the COMPASS experiment at CERN, pion-photon reactions are investigated via the Primakoff effect, implying that high-energetic pions react with the quasi-real photon field surrounding the target nuclei. The production of a single hard photon in such a pion scattering at lowest momentum transfer to the nucleus is related to pion Compton scattering. From the measured cross-section shape, the pion polarisability is determined. The COMPASS measurement is in contradiction to the earlier dedicated measurements, and rather in agreement with the theoretical expectation from chiral perturbation theory. In the same data taking, reactions with neutral and charged pions in the finalmore » state are measured and analyzed. At low energy in the pion-photon centre-of-momentum system, these reactions are governed by chiral dynamics and contain information relevant for chiral perturbation theory. At higher energies, resonances are produced and their radiative coupling is investigated.« less

In-medium Chiral Perturbation Theory beyond the Mean-Field Approximation

NASA Astrophysics Data System (ADS)

Meißner, Ulf-G.; Oller, José A.; Wirzba, Andreas

2002-04-01

An explicit expression for the generating functional of two-flavor low-energy QCD with external sources in the presence of nonvanishing nucleon densities was derived recently (J. A. Oller, Phys. Rev. C65 (2002) 025204). Within this approach we derive power counting rules for the calculation of in-medium pion properties. We develop the so-called standard rules for residual nucleon energies of the order of the pion mass and a modified scheme (nonstandard counting) for vanishing residual nucleon energies. We also establish the different scales for the range of applicability of this perturbative expansion, which are 6πfπ≃0.7 GeV for standard and 6π2fπ2/2mN≃0.27 GeV for nonstandard counting, respectively. We have performed a systematic analysis of n-point in-medium Green functions up to and including next-to-leading order when the standard rules apply. These include the in-medium contributions to quark condensates, pion propagators, pion masses, and couplings of the axial-vector, vector, and pseudoscalar currents to pions. In particular, we find a mass shift for negatively charged pions in heavy nuclei, ΔMπ-=(18±m 5) MeV, that agrees with recent determinations from deeply bound pionic 207Pb. We have also established the absence of in-medium renormalization in the π0→γγ decay amplitude up to the same order. The study of ππ scattering requires the use of the nonstandard counting and the calculation is done at leading order. Even at that order we establish new contributions not considered so far. We also point toward further possible improvements of this scheme and touch upon its relation to more conventional many-body approaches.

Inverse magnetic catalysis from improved holographic QCD in the Veneziano limit

NASA Astrophysics Data System (ADS)

Gürsoy, Umut; Iatrakis, Ioannis; Järvinen, Matti; Nijs, Govert

2017-03-01

We study the dependence of the chiral condensate on external magnetic field in the context of holographic QCD at large number of flavors. We consider a holographic QCD model where the flavor degrees of freedom fully backreact on the color dynamics. Perturbative QCD calculations have shown that B acts constructively on the chiral condensate, a phenomenon called "magnetic catalysis". In contrast, recent lattice calculations show that, depending on the number of flavors and temperature, the magnetic field may also act destructively, which is called "inverse magnetic catalysis". Here we show that the holographic theory is capable of both behaviors depending on the choice of parameters. For reasonable choice of the potentials entering the model we find qualitative agreement with the lattice expectations. Our results provide insight for the physical reasons behind the inverse magnetic catalysis. In particular, we argue that the backreaction of the flavors to the background geometry decatalyzes the condensate.

Chiral effective theory of dark matter direct detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishara, Fady; Brod, Joachim; Grinstein, Benjamin

2017-02-01

We present the effective field theory for dark matter interactions with the visible sector that is valid at scales of O(1 GeV). Starting with an effective theory describing the interactions of fermionic and scalar dark matter with quarks, gluons and photons via higher dimension operators that would arise from dimension-five and dimension-six operators above electroweak scale, we perform a nonperturbative matching onto a heavy baryon chiral perturbation theory that describes dark matter interactions with light mesons and nucleons. This is then used to obtain the coefficients of the nuclear response functions using a chiral effective theory description of nuclear forces.more » Our results consistently keep the leading contributions in chiral counting for each of the initial Wilson coefficients.« less

Spectroscopy of the BSM sextet model

NASA Astrophysics Data System (ADS)

Fodor, Zoltan; Holland, Kieran; Kuti, Julius; Nogradi, Daniel; Wong, Chik Him

2018-03-01

As part of our ongoing lattice study of SU(3) gauge theory with two flavors of fermions in the two-index symmetric representation (the sextet model), we present the current status of the pseudoscalar particle spectrum. We use a mixed action approach based on the gradient flow to control lattice artifacts, allowing a simultaneous extrapolation to the chiral and continuum limits. We find strong evidence that the pseudoscalar is a Goldstone boson state, with spontaneously broken chiral symmetry and a non-zero Goldstone decay constant in the chiral limit. In agreement with our study of the gauge coupling β function, we find the sextet model appears to be a near-conformal gauge theory and serves as a prototype of the composite Higgs BSM template.

Aspects of Chiral Symmetry Breaking in Lattice QCD

NASA Astrophysics Data System (ADS)

Horkel, Derek P.

phase diagram is unaffected by the inclusion of electromagnetism--the only effect is to raise the charged pion masses. For maximally twisted fermions, we previously took the twist and isospin-breaking directions to be different, in order that the fermion determinant is real and positive. However, this is incompatible with electromagnetic gauge invariance, and so here we take the twist to be in the isospin-breaking direction, following the RM123 collaboration. We map out the phase diagram in this case, which has not previously been studied. The results differ from those obtained with different twist and isospin directions. One practical issue when including electromagnetism is that the critical masses for up and down quarks differ. We show that one of the criteria suggested to determine these critical masses does not work, and propose an alternative. In chapter 4, we delve deeper into the technical details of the analysis in chapter 3. We determine the phase diagram and chiral condensate for lattice QCD with two flavors of twisted-mass fermions in the presence of nondegenerate up and down quarks, discretization errors and a nonzero value of thetaQCD. We find that, in general, the only phase structure is a first-order transition of finite length. Pion masses are nonvanishing throughout the phase plane except at the endpoints of the first-order line. Only for extremal values of the twist angle and thetaQCD (o = 0 or pi/2 and thetaQCD = 0 or pi) are there second-order transitions. In chapter 5 we move on to a new topic, working to make a first measurement of non-perturbative Greens functions which vanish in perturbation theory but have a non-vanishing one-instanton contribution, as suggested in recent work by Dine et. al. [24] using a semi- classical approach. This measurement was done using 163 x 48 configurations generated by the MILC collaboration, with coupling beta = 6.572, light quark mass m la = 0.0097, strange quark mass msa = 0.0484, lattice spacing a ≈ 0.14 fm

Incomplete immunity to backscattering in chiral one-way photonic crystals.

PubMed

Cheng, Pi-Ju; Tien, Chung-Hao; Chang, Shu-Wei

2015-04-20

We show that the propagating modes in a strongly-guided chiral one-way photonic crystal are not backscattering-immune even though they are indeed insensitive to many kinds of scatters. Since these modes are not protected by the nonreciprocity, the backscattering does occur under certain circumstances. We use a perturbative method to derive criteria for the prominent backscattering in such chiral structures. From both our theory and numerical examinations, we find that the amount of backscattering critically depends on the symmetry of scatters. Additionally, for these chiral photonic modes, disturbances at the most intense parts of field profiles do not necessarily lead to the most effective backscattering.

Spontaneous Planar Chiral Symmetry Breaking in Cells

NASA Astrophysics Data System (ADS)

Hadidjojo, Jeremy; Lubensky, David

Recent progress in animal development has highlighted the central role played by planar cell polarity (PCP) in epithelial tissue morphogenesis. Through PCP, cells have the ability to collectively polarize in the plane of the epithelium by localizing morphogenetic proteins along a certain axis. This allows direction-dependent modulation of tissue mechanical properties that can translate into the formation of complex, non-rotationally invariant shapes. Recent experimental observations[1] show that cells, in addition to being planar-polarized, can also spontaneously develop planar chirality, perhaps in the effort of making yet more complex shapes that are reflection non-invariant. In this talk we will present our work in characterizing general mechanisms that can lead to spontaneous chiral symmetry breaking in cells. We decompose interfacial concentration of polarity proteins in a hexagonal cell packing into irreducible representations. We find that in the case of polar concentration distributions, a chiral state can only be reached from a secondary instability after the cells are polarized. However in the case of nematic distributions, we show that a finite-amplitude (subcritical, or ``first-order'') nematic transition can send the system from disorder directly to a chiral state. In addition, we find that perturbing the system by stretching the hexagonal packing enables direct (supercritical, or ``second-order'') chiral transition in the nematic case. Finally, we do a Landau expansion to study competition between stretch-induced chirality and the tendency towards a non-chiral state in packings that have retained the full 6-fold symmetry.

The chiral separation of triazole pesticides enantiomers by amylose-tris (3,5-dimethylphenylcarbamate) chiral stationary phase.

PubMed

Wang, Peng; Liu, Donghui; Jiang, Shuren; Xu, Yangguang; Zhou, Zhiqiang

2008-10-01

The amylose-tris(3,5-dimethylphenylcarbamate) chiral stationary phase was synthesized and used to separate the enantiomers of triazole pesticides by high-performance liquid chromatography. The mobile phase was n-hexane-isopropanol applying a flow rate of 1.0 mL/min. Six triazole pesticides were enantioselectively separated. Myclobutanil, paclobutrazol, tebuconazole, and uniconazole obtained complete separation with the resolution factors of 5.73, 2.99, 1.72, and 2.07, respectively, and imazalil and diniconazole obtained partial separation with the resolution factors of 0.79 and 0.77 under the optimized conditions. The effect of the content of isopropanol as well as column temperature on the separation was investigated. A circular dichroism detector was used to identify the enantiomers and determine the elution orders. The results showed the low temperature was good for the chiral separation except for diniconazole. The thermodynamic parameters calculated based on linear Van't Hoff plots showed the chiral separations were controlled by enthalpy.

Quantum Chromodynamics and Color Confinement (confinement 2000) - Proceedings of the International Symposium

NASA Astrophysics Data System (ADS)

Suganuma, H.; Fukushima, M.; Toki, H.

-diagonal Gluon Phase in the Maximally Abelian Gauge * On the Colour Confinement and the Minimal Surface * Glueball Mass and String Tension of SU(2) Gluodynamics from Abelian Monopoles and Strings * Application of the Non-Perturbative Renormalization Group to the Nambu-Jona-Lasinio Model at Finite Temperature and Density * Confining Flux-Tube and Hadrons in QCD * Gauge Symmetry Breakdown due to Dynamical Higgs Scalar * Spatial Structure of Quark Cooper Pairs * New Approach to Axial Coupling Constants in the QCD Sum Rule and Instanton Effects * String Breaking on a Lattice * Bethe-Salpeter Approach for Mesons within the Dual Ginzburg-Landau Theory * Gauge Dependence and Matching Procedure of a Nonrelativistic QCD Boundstate Formalism * A Mathematical Approach to the SU(2)-Quark Confinement * Simulations of Odd Flavors QCD by Hybrid Monte Carlo * Non-Perturbative Renormalization Group Analysis of Dynamical Chiral Symmetry Breaking with Beyond Ladder Contributions * Charmonium Physics in Finite Temperature Lattice QCD * From Meson-Nucleon Scattering to Vector Mesons in Nuclear Matter * Symposium Program * List of Participants

Gut T1R3 sweet taste receptors do not mediate sucrose-conditioned flavor preferences in mice.

PubMed

Sclafani, Anthony; Glass, Damien S; Margolskee, Robert F; Glendinning, John I

2010-12-01

Most mammals prefer the sweet taste of sugars, which is mediated by the heterodimeric T1R2+T1R3 taste receptor. Sugar appetite is also enhanced by the post-oral reinforcing actions of the nutrient in the gut. Here, we examined the contribution of gut T1R3 (either alone or as part of the T1R3+T1R3 receptor) to post-oral sugar reinforcement using a flavor-conditioning paradigm. We trained mice to associate consumption of a flavored solution (CS+) with intragastric (IG) infusions of a sweetener, and a different flavored solution (CS-) with IG infusions of water (23 h/day); then, we measured preference in a CS+ vs. CS- choice test. In experiment 1, we predicted that if activation of gut T1R3 mediates sugar reinforcement, then IG infusions of a nutritive (sucrose) or nonnutritive (sucralose) ligand for this receptor should condition a preference for the CS+ in B6 wild-type (WT) mice. While the mice that received IG sucrose infusions developed a strong preference for the CS+, those that received IG sucralose infusions developed a weak avoidance of the CS+. In experiment 2, we used T1R3 knockout (KO) mice to examine the necessity of gut T1R2+T1R3 receptors for conditioned flavor preferences. If intact gut T1R3 (or T1R2+T1R3) receptors are necessary for flavor-sugar conditioning, then T1R3 KO mice should not develop a sugar-conditioned flavor preference. We found that T1R3 KO mice, like WT mice, acquired a strong preference for the CS+ paired with IG sucrose infusions. The KO mice were also like WT mice in avoiding a CS+ flavor paired with IG sucralose infusions These findings provide clear evidence that gut T1R3 receptors are not necessary for sugar-conditioned flavor preferences or sucralose-induced flavor avoidance in mice.

Conformal versus confining scenario in SU(2) with adjoint fermions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Debbio, L.; Pica, C.; Lucini, B.

2009-10-01

The masses of the lowest-lying states in the meson and in the gluonic sector of an SU(2) gauge theory with two Dirac flavors in the adjoint representation are measured on the lattice at a fixed value of the lattice coupling {beta}=4/g{sub 0}{sup 2}=2.25 for values of the bare fermion mass m{sub 0} that span a range between the quenched regime and the massless limit, and for various lattice volumes. Even for light constituent fermions the lightest glueballs are found to be lighter than the lightest mesons. Moreover, the string tension between two static fundamental sources strongly depends on the massmore » of the dynamical fermions and becomes of the order of the inverse squared lattice linear size before the chiral limit is reached. The implications of these findings for the phase of the theory in the massless limit are discussed and a strategy for discriminating between the (near-)conformal and the confining scenario is outlined.« less

FlavorDB: a database of flavor molecules

PubMed Central

Garg, Neelansh; Sethupathy, Apuroop; Tuwani, Rudraksh; NK, Rakhi; Dokania, Shubham; Iyer, Arvind; Gupta, Ayushi; Agrawal, Shubhra; Singh, Navjot; Shukla, Shubham; Kathuria, Kriti; Badhwar, Rahul; Kanji, Rakesh; Jain, Anupam; Kaur, Avneet; Nagpal, Rashmi

2018-01-01

Abstract Flavor is an expression of olfactory and gustatory sensations experienced through a multitude of chemical processes triggered by molecules. Beyond their key role in defining taste and smell, flavor molecules also regulate metabolic processes with consequences to health. Such molecules present in natural sources have been an integral part of human history with limited success in attempts to create synthetic alternatives. Given their utility in various spheres of life such as food and fragrances, it is valuable to have a repository of flavor molecules, their natural sources, physicochemical properties, and sensory responses. FlavorDB (http://cosylab.iiitd.edu.in/flavordb) comprises of 25,595 flavor molecules representing an array of tastes and odors. Among these 2254 molecules are associated with 936 natural ingredients belonging to 34 categories. The dynamic, user-friendly interface of the resource facilitates exploration of flavor molecules for divergent applications: finding molecules matching a desired flavor or structure; exploring molecules of an ingredient; discovering novel food pairings; finding the molecular essence of food ingredients; associating chemical features with a flavor and more. Data-driven studies based on FlavorDB can pave the way for an improved understanding of flavor mechanisms. PMID:29059383

Chiral superconductors.

PubMed

Kallin, Catherine; Berlinsky, John

2016-05-01

Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.

Visualizing the chiral anomaly in Dirac and Weyl semimetals with photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Behrends, Jan; Grushin, Adolfo G.; Ojanen, Teemu; Bardarson, Jens H.

2016-02-01

Quantum anomalies are the breaking of a classical symmetry by quantum fluctuations. They dictate how physical systems of diverse nature, ranging from fundamental particles to crystalline materials, respond topologically to external perturbations, insensitive to local details. The anomaly paradigm was triggered by the discovery of the chiral anomaly that contributes to the decay of pions into photons and influences the motion of superfluid vortices in 3He-A. In the solid state, it also fundamentally affects the properties of topological Weyl and Dirac semimetals, recently realized experimentally. In this work we propose that the most identifying consequence of the chiral anomaly, the charge density imbalance between fermions of different chirality induced by nonorthogonal electric and magnetic fields, can be directly observed in these materials with the existing technology of photoemission spectroscopy. With angle resolution, the chiral anomaly is identified by a characteristic note-shaped pattern of the emission spectra, originating from the imbalanced occupation of the bulk states and a previously unreported momentum dependent energy shift of the surface state Fermi arcs. We further demonstrate that the chiral anomaly likewise leaves an imprint in angle averaged emission spectra, facilitating its experimental detection. Thereby, our work provides essential theoretical input to foster the direct visualization of the chiral anomaly in condensed matter, in contrast to transport properties, such as negative magnetoresistance, which can also be obtained in the absence of a chiral anomaly.

Double interpenetration in a chiral three-dimensional magnet with a (10,3)-a structure.

PubMed

Grancha, Thais; Mon, Marta; Lloret, Francesc; Ferrando-Soria, Jesús; Journaux, Yves; Pasán, Jorge; Pardo, Emilio

2015-09-21

A unique chiral three-dimensional magnet with an overall racemic double-interpenetrated (10,3)-a structure of the formula [(S)-(1-PhEt)Me3N]4[Mn4Cu6(Et2pma)12](DMSO)3]·3DMSO·5H2O (1; Et2pma = N-2,6-diethylphenyloxamate) has been synthesized by the self-assembly of a mononuclear copper(II) complex acting as a metalloligand toward Mn(II) ions in the presence of a chiral cationic auxiliary, constituting the first oxamato-based chiral coordination polymer exhibiting long-range magnetic ordering.

Color superconductivity from the chiral quark-meson model

NASA Astrophysics Data System (ADS)

Sedrakian, Armen; Tripolt, Ralf-Arno; Wambach, Jochen

2018-05-01

We study the two-flavor color superconductivity of low-temperature quark matter in the vicinity of chiral phase transition in the quark-meson model where the interactions between quarks are generated by pion and sigma exchanges. Starting from the Nambu-Gorkov propagator in real-time formulation we obtain finite temperature (real axis) Eliashberg-type equations for the quark self-energies (gap functions) in terms of the in-medium spectral function of mesons. Exact numerical solutions of the coupled nonlinear integral equations for the real and imaginary parts of the gap function are obtained in the zero temperature limit using a model input spectral function. We find that these components of the gap display a complicated structure with the real part being strongly suppressed above 2Δ0, where Δ0 is its on-shell value. We find Δ0 ≃ 40MeV close to the chiral phase transition.

FlavorDB: a database of flavor molecules.

PubMed

Garg, Neelansh; Sethupathy, Apuroop; Tuwani, Rudraksh; Nk, Rakhi; Dokania, Shubham; Iyer, Arvind; Gupta, Ayushi; Agrawal, Shubhra; Singh, Navjot; Shukla, Shubham; Kathuria, Kriti; Badhwar, Rahul; Kanji, Rakesh; Jain, Anupam; Kaur, Avneet; Nagpal, Rashmi; Bagler, Ganesh

2018-01-04

Flavor is an expression of olfactory and gustatory sensations experienced through a multitude of chemical processes triggered by molecules. Beyond their key role in defining taste and smell, flavor molecules also regulate metabolic processes with consequences to health. Such molecules present in natural sources have been an integral part of human history with limited success in attempts to create synthetic alternatives. Given their utility in various spheres of life such as food and fragrances, it is valuable to have a repository of flavor molecules, their natural sources, physicochemical properties, and sensory responses. FlavorDB (http://cosylab.iiitd.edu.in/flavordb) comprises of 25,595 flavor molecules representing an array of tastes and odors. Among these 2254 molecules are associated with 936 natural ingredients belonging to 34 categories. The dynamic, user-friendly interface of the resource facilitates exploration of flavor molecules for divergent applications: finding molecules matching a desired flavor or structure; exploring molecules of an ingredient; discovering novel food pairings; finding the molecular essence of food ingredients; associating chemical features with a flavor and more. Data-driven studies based on FlavorDB can pave the way for an improved understanding of flavor mechanisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Quantum Electrodynamics in d=3 from the ε Expansion.

PubMed

Di Pietro, Lorenzo; Komargodski, Zohar; Shamir, Itamar; Stamou, Emmanuel

2016-04-01

We study quantum electrodynamics in d=3 coupled to N_{f} flavors of fermions. The theory flows to an IR fixed point for N_{f} larger than some critical number N_{f}^{c}. For N_{f}≤N_{f}^{c}, chiral-symmetry breaking is believed to take place. In analogy with the Wilson-Fisher description of the critical O(N) models in d=3, we make use of the existence of a fixed point in d=4-2ε to study the three-dimensional conformal theory. We compute, in perturbation theory, the IR dimensions of fermion bilinear and quadrilinear operators. For small N_{f}, a quadrilinear operator can become relevant in the IR and destabilize the fixed point. Therefore, the epsilon expansion can be used to estimate N_{f}^{c}. An interesting novelty compared to the O(N) models is that the theory in d=3 has an enhanced symmetry due to the structure of 3D spinors. We identify the operators in d=4-2ε that correspond to the additional conserved currents at d=3 and compute their infrared dimensions.

Enhanced flavor-nutrient conditioning in obese rats on a high-fat, high-carbohydrate choice diet.

PubMed

Wald, Hallie S; Myers, Kevin P

2015-11-01

Through flavor-nutrient conditioning rats learn to prefer and increase their intake of flavors paired with rewarding, postingestive nutritional consequences. Since obesity is linked to altered experience of food reward and to perturbations of nutrient sensing, we investigated flavor-nutrient learning in rats made obese using a high fat/high carbohydrate (HFHC) choice model of diet-induced obesity (ad libitum lard and maltodextrin solution plus standard rodent chow). Forty rats were maintained on HFHC to induce substantial weight gain, and 20 were maintained on chow only (CON). Among HFHC rats, individual differences in propensity to weight gain were studied by comparing those with the highest proportional weight gain (obesity prone, OP) to those with the lowest (obesity resistant, OR). Sensitivity to postingestive food reward was tested in a flavor-nutrient conditioning protocol. To measure initial, within-meal stimulation of flavor acceptance by post-oral nutrient sensing, first, in sessions 1-3, baseline licking was measured while rats consumed grape- or cherry-flavored saccharin accompanied by intragastric (IG) water infusion. Then, in the next three test sessions they received the opposite flavor paired with 5 ml of IG 12% glucose. Finally, after additional sessions alternating between the two flavor-infusion contingencies, preference was measured in a two-bottle choice between the flavors without IG infusions. HFHC-OP rats showed stronger initial enhancement of intake in the first glucose infusion sessions than CON or HFHC-OR rats. OP rats also most strongly preferred the glucose-paired flavor in the two-bottle choice. These differences between OP versus OR and CON rats suggest that obesity is linked to responsiveness to postoral nutrient reward, consistent with the view that flavor-nutrient learning perpetuates overeating in obesity. Copyright © 2015 Elsevier Inc. All rights reserved.

Chiral Polymers.

DTIC Science & Technology

1984-10-01

regardless of the method of polymerization. The styrene-bead copolymers were packed in HPLC columns, but none were especiall, effective in separating...enantiomers in a racemic mixture. The chiral butyrolactone polymer was coated on silica, but this material did not effect resolution of racemic mixtures in an...been effected utilizing chiral oxazolines3 prompted the initial efforts to synthesize various chiral 2-vinyl- oxazoline monomers for incorporation

Chiral Odd Structure Functions in The Nambu--Jona--Lasinio Soliton Model

NASA Astrophysics Data System (ADS)

Gamberg, Leonard; Reinhardt, Hugo; Weigel, Herbert

1998-10-01

We study unpolarized and polarized nucleon structure functions(H. Weigel, L. Gamberg, and H. Reinhardt, Mod. Phys. Lett. A11) (1996) 3021; Phys. Lett. B399 (1997) 287;Phys. Rev. D55(1997) 6910. within the bosonized Nambu--Jona--Lasinio (NJL) model where the nucleon emerges as a chiral soliton(R. Alkofer, H. Reinhardt and H. Weigel, Phys. Rep. 265) (1996) 139.. These considerations attempt to merge the parton model description of deep inelastic scattering with the phenomenologically successful picture of baryons as chiral solitons. In addition we report on the calculation of the chiral odd quark distributions(L. Gamberg, H. Reinhardt and H. Weigel, "Chiral odd structure functions from a chiral soliton", hep-ph/9801379, Phys. Rev. D. in press.) and the corresponding structure functions h_T(x,Q^2) and h_L(x,Q^2). At the low model scale, Q_0^2, we find that the leading twist effective quark distributions, f_1^(q)(x,Q_0^2), g_1^(q)(x,Q_0^2) and h_T^(q)(x,Q_0^2) satisfy Soffer's inequality for both quark flavors q=u,d. The Q^2 evolution of the twist--2 contributions is performed according to the standard GLAP formalism while the twist--three pieces, \\overlineg_2(x) and \\overlineh_L(x), are evolved according to the large NC scheme.

Chiral gravitational waves and baryon superfluid dark matter

NASA Astrophysics Data System (ADS)

Alexander, Stephon; McDonough, Evan; Spergel, David N.

2018-05-01

We develop a unified model of darkgenesis and baryogenesis involving strongly interacting dark quarks, utilizing the gravitational anomaly of chiral gauge theories. In these models, both the visible and dark baryon asymmetries are generated by the gravitational anomaly induced by the presence of chiral primordial gravitational waves. We provide a concrete model of an SU(2) gauge theory with two massless quarks. In this model, the dark quarks condense and form a dark baryon charge superfluid (DBS), in which the Higgs-mode acts as cold dark matter. We elucidate the essential features of this dark matter scenario and discuss its phenomenological prospects.

Prospecting for new physics in the Higgs and flavor sectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishara, Fady

We explore two directions in beyond the standard model physics: dark matter model building and probing new sources of CP violation. In dark matter model building, we consider two scenarios where the stability of dark matter derives from the flavor symmetries of the standard model. The first model contains a flavor singlet dark matter candidate whose couplings to the visible sector are proportional to the flavor breaking parameters. This leads to a metastable dark matter with TeV scale mediators. In the second model, we consider a fully gauged SU(3) 3 flavor model with a flavor triplet dark matter. Consequently, the dark matter multiplet is charged while the standard model fields are neutral under a remnant Z 3 which ensures dark matter stability. We show that a Dirac fermion dark matter with radiative splitting in the multiplet must have a mass in the range [0:5; 5] TeV in order to satisfy all experimental constraints. We then turn our attention to Higgs portal dark matter and investigate the possibility of obtaining bounds on the up, down, and strange quark Yukawa couplings. If Higgs portal dark matter is discovered, we find that direct detection rates are insensitive to vanishing light quark Yukawa couplings. We then review flavor models and give the expected enhancement or suppression of the Yukawa couplings in those models. Finally, in the last two chapters, we develop techniques for probing CP violation in the Higgs coupling to photons and in rare radiative decays of B mesons. While theoretically clean, we find that these methods are not practical with current and planned detectors. However, these techniques can be useful with a dedicated detector (e.g., a gaseous TPC). In the case of radiative B meson decay B 0 → (K* → Kππ) γ, the techniques we develop also allow the extraction of the photon polarization fraction which is sensitive to new physics contributions since, in the standard model, the right(left) handed polarization fraction is of O( Λ QCD

Precursors of chicken flavor. II. Identification of key flavor precursors using sensory methods.

PubMed

Aliani, Michel; Farmer, Linda J

2005-08-10

Sensory evaluation was used to identify flavor precursors that are critical for flavor development in cooked chicken. Among the potential flavor precursors studied (thiamin, inosine 5'-monophosphate, ribose, ribose-5-phosphate, glucose, and glucose-6-phosphate), ribose appears most important for chicken aroma. An elevated concentration (added or natural) of only 2-4-fold the natural concentration gives an increase in the selected aroma and flavor attributes of cooked chicken meat. Assessment of the volatile odor compounds by gas chromatography-odor assessment and gas chromatography-mass spectrometry showed that ribose increased odors described as "roasted" and "chicken" and that the changes in odor due to additional ribose are probably caused by elevated concentrations of compounds such as 2-furanmethanethiol, 2-methyl-3-furanthiol, and 3-methylthiopropanal.

Strangeness and charmness content of the nucleon from overlap fermions on 2+1-flavor domain-wall fermion configurations

NASA Astrophysics Data System (ADS)

Gong, M.; Alexandru, A.; Chen, Y.; Doi, T.; Dong, S. J.; Draper, T.; Freeman, W.; Glatzmaier, M.; Li, A.; Liu, K. F.; Liu, Z.

2013-07-01

We present a calculation of the strangeness and charmness contents ⟨N|s¯s|N⟩ and ⟨N|c¯c|N⟩ of the nucleon from dynamical lattice QCD with 2+1 flavors. The calculation is performed with overlap valence quarks on 2+1-flavor domain-wall fermion gauge configurations. The configurations are generated by the RBC collaboration on a 243×64 lattice with sea-quark mass aml=0.005, ams=0.04, and inverse lattice spacing a-1=1.73GeV. Both actions have chiral symmetry which is essential in avoiding contamination due to the operator mixing with other flavors. The nucleon propagator and the quark loops are both computed with stochastic grid sources, while low-mode substitution and low-mode averaging methods are used respectively which substantially improve the signal-to-noise ratio. We obtain the strangeness matrix element fTs=ms⟨N|s¯s|N⟩/MN=0.0334(62), and the charmness content fTc=mc⟨N|c¯c|N⟩/MN=0.094(31) which is resolved from zero by 3σ precision for the first time.

3D chiral nanoplasmonics: fabrication, chiroptic engineering, mechanism, and application in enantioselection (Presentation Recording)

NASA Astrophysics Data System (ADS)

Huang, Zhifeng

2015-09-01

Chirality does naturally exist, and the building blocks of life (e.g. DNA, proteins, peptides and sugars) are usually chiral. Chirality inherently imposes chemical/biological selectivity on functional molecules; hence the discrimination in molecular chirality from an enantiomer to the other mirror image (i.e. enantioselection) has fundamental and application significance. Enantiomers interact with left and right handed circularly polarized light in a different manner with respect to optical extinction; hence, electronic circular dichroism (ECD) has been widely used for enantioselection. However, enantiomers usually have remarkably low ECD intensity, mainly owing to the small electric transition dipole moment induced by molecular sizes compared to the ECD-active wavelength in the UV-visible-near IR region. To enhance ECD magnitude, recently it has being developed 3D chiral nanoplasmonic structures having a helical path, and the dimensions are comparable to the ECD wavelength. However, it is still ambiguous the origin of 3D chiroplasmonics, and there is a lack of studying the interaction of 3D chiroplasmoncs with enantiomers for the application of enantioselection. Herein, we will present a one-step fabrication of 3D silver nanospirals (AgNSs) via low-substrate-temperature glancing angle deposition. AgNSs can be deposited on a wide range of substrates (including transparent and flexible substrates), in an area on the order of cm2. A set of spiral dimensions (such as spiral pitches, number of turns and handedness) have been easily engineered to tune the chiroptic properties, leading to studying the chiroplasmonic principles together with finite element simulation and the LC model. At the end, it will be demonstrated that 3D chiroplasmonics can differentiate molecular chirality of enantiomers with dramatic enhancement in the anisotropy g factor. This study opens a door to sensitively discriminate enantiomer chirality.

Criteria of backscattering in chiral one-way photonic crystals

NASA Astrophysics Data System (ADS)

Cheng, Pi-Ju; Chang, Shu-Wei

2016-03-01

Optical isolators are important devices in photonic circuits. To reduce the unwanted reflection in a robust manner, several setups have been realized using nonreciprocal schemes. In this study, we show that the propagating modes in a strongly-guided chiral photonic crystal (no breaking of the reciprocity) are not backscattering-immune even though they are indeed insensitive to many types of scatters. Without the protection from the nonreciprocity, the backscattering occurs under certain circumstances. We present a perturbative method to calculate the backscattering of chiral photonic crystals in the presence of chiral/achiral scatters. The model is, essentially, a simplified analogy to the first-order Born approximation. Under reasonable assumptions based on the behaviors of chiral photonic modes, we obtained the expression of reflection coefficients which provides criteria for the prominent backscattering in such chiral structures. Numerical examinations using the finite-element method were also performed and the results agree well with the theoretical prediction. From both our theory and numerical calculations, we find that the amount of backscattering critically depends on the symmetry of scatter cross sections. Strong reflection takes place when the azimuthal Fourier components of scatter cross sections have an order l of 2. Chiral scatters without these Fourier components would not efficiently reflect the chiral photonic modes. In addition, for these chiral propagating modes, disturbances at the most significant parts of field profiles do not necessarily result in the most effective backscattering. The observation also reveals what types of scatters or defects should be avoided in one-way applications of chiral structures in order to minimize the backscattering.

Unified, flavor symmetric explanation for the tt asymmetry and Wjj excess at CDF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Ann E.; Roy, Tuhin S.; Okui, Takemichi

2011-11-01

We present a simple, perturbative, and renormalizable model with a flavor symmetry which can explain both the tt forward-backward asymmetry and the bump feature present in the dijet mass distribution of the W+jj sample in the range 120-160 GeV that was recently reported by the CDF collaboration. The flavor symmetry not only ensures the flavor/CP safety of the model, but also relates the two anomalies unambiguously. It predicts a comparable forward-backward asymmetry in cc. The forward-backward asymmetry in bb is, however, small. A bump in the dijet mass distribution in Z+jj sample is also predicted but with a suppressed crossmore » section.« less

Dynamically flavored description of holographic QCD in the presence of a magnetic field

NASA Astrophysics Data System (ADS)

Li, Si-wen; Jia, Tuo

2017-09-01

We construct the gravitational solution of the Witten-Sakai-Sugimoto model by introducing a magnetic field on the flavor brane. Taking into account their backreaction, we re-solve type IIA supergravity in the presence of a magnetic field. Our calculation shows that the gravitational solutions are magnetically dependent and analytic both in the bubble (confined) and black brane (deconfined) case. We study the dual field theory at the leading order in the ratio of the number of flavors and colors, and also in the Veneziano limit. Some physical properties related to the hadronic physics in an external magnetic field are discussed by using our confined backreaction solution holographically. We also investigate the thermodynamics and holographic renormalization of this model in both phases by our solution. Since the backreaction of the magnetic field is considered in our gravitational solution, it allows us to study the Hawking-Page transition with flavors and colors of this model in the presence of the magnetic field. Finally we therefore obtain the holographic phase diagram with the contributions from the flavors and the magnetic field. Our holographic phase diagram is in qualitative agreement with the lattice QCD result, which thus can be interpreted as the inhibition of confinement or chirally broken symmetry by the magnetic field.

Flavor and stability of milk proteins.

PubMed

Smith, T J; Campbell, R E; Jo, Y; Drake, M A

2016-06-01

A greater understanding of the nature and source of dried milk protein ingredient flavor(s) is required to characterize flavor stability and identify the sources of flavors. The objective of this study was to characterize the flavor and flavor chemistry of milk protein concentrates (MPC 70, 80, 85), isolates (MPI), acid and rennet caseins, and micellar casein concentrate (MCC) and to determine the effect of storage on flavor and functionality of milk protein concentrates using instrumental and sensory techniques. Spray-dried milk protein ingredients (MPC, MPI, caseins, MCC) were collected in duplicate from 5 commercial suppliers or manufactured at North Carolina State University. Powders were rehydrated and evaluated in duplicate by descriptive sensory analysis. Volatile compounds were extracted by solid phase microextraction followed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry. Compounds were identified by comparison of retention indices, odor properties, and mass spectra against reference standards. A subset of samples was selected for further analysis using direct solvent extraction with solvent-assisted flavor extraction, and aroma extract dilution analysis. External standard curves were created to quantify select volatile compounds. Pilot plant manufactured MPC were stored at 3, 25, and 40°C (44% relative humidity). Solubility, furosine, sensory properties, and volatile compound analyses were performed at 0, 1, 3, 6, and 12 mo. Milk proteins and caseins were diverse in flavor and exhibited sweet aromatic and cooked/milky flavors as well as cardboard, brothy, tortilla, soapy, and fatty flavors. Key aroma active compounds in milk proteins and caseins were 2-aminoacetophenone, nonanal, 1-octen-3-one, dimethyl trisulfide, 2-acetyl-1-pyrroline, heptanal, methional, 1-hexen-3-one, hexanal, dimethyl disulfide, butanoic acid, and acetic acid. Stored milk proteins developed animal and burnt sugar flavors over time. Solubility of

Nuclear axial currents in chiral effective field theory

DOE PAGES

Baroni, Alessandro; Girlanda, Luca; Pastore, Saori; ...

2016-01-11

Two-nucleon axial charge and current operators are derived in chiral effective field theory up to one loop. The derivation is based on time-ordered perturbation theory and accounts for cancellations between the contributions of irreducible diagrams and the contributions owing to nonstatic corrections from energy denominators of reducible diagrams. Ultraviolet divergencies associated with the loop corrections are isolated in dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. As a result, a complete set of contact terms for the axial charge up to the relevant order in the power countingmore » is constructed.« less

Absolute Configuration of 3-METHYLCYCLOHEXANONE by Chiral Tag Rotational Spectroscopy and Vibrational Circular Dichroism

NASA Astrophysics Data System (ADS)

Evangelisti, Luca; Holdren, Martin S.; Mayer, Kevin J.; Smart, Taylor; West, Channing; Pate, Brooks

2017-06-01

The absolute configuration of 3-methylcyclohexanone was established by chiral tag rotational spectroscopy measurements using 3-butyn-2-ol as the tag partner. This molecule was chosen because it is a benchmark measurement for vibrational circular dichroism (VCD). A comparison of the analysis approaches of chiral tag rotational spectroscopy and VCD will be presented. One important issue in chiral analysis by both methods is the conformational flexibility of the molecule being analyzed. The analysis of conformational composition of samples will be illustrated. In this case, the high spectral resolution of molecular rotational spectroscopy and potential for spectral simplification by conformational cooling in the pulsed jet expansion are advantages for chiral tag spectroscopy. The computational chemistry requirements for the two methods will also be discussed. In this case, the need to perform conformer searches for weakly bound complexes and to perform reasonably high level quantum chemistry geometry optimizations on these complexes makes the computational time requirements less favorable for chiral tag rotational spectroscopy. Finally, the issue of reliability of the determination of the absolute configuration will be considered. In this case, rotational spectroscopy offers a "gold standard" analysis method through the determination of the ^{13}C-subsitution structure of the complex between 3-methylcyclohexanone and an enantiopure sample of the 3-butyn-2-ol tag.

Chiral extrapolation of the leading hadronic contribution to the muon anomalous magnetic moment

NASA Astrophysics Data System (ADS)

Golterman, Maarten; Maltman, Kim; Peris, Santiago

2017-04-01

A lattice computation of the leading-order hadronic contribution to the muon anomalous magnetic moment can potentially help reduce the error on the Standard Model prediction for this quantity, if sufficient control of all systematic errors affecting such a computation can be achieved. One of these systematic errors is that associated with the extrapolation to the physical pion mass from values on the lattice larger than the physical pion mass. We investigate this extrapolation assuming lattice pion masses in the range of 200 to 400 MeV with the help of two-loop chiral perturbation theory, and we find that such an extrapolation is unlikely to lead to control of this systematic error at the 1% level. This remains true even if various tricks to improve the reliability of the chiral extrapolation employed in the literature are taken into account. In addition, while chiral perturbation theory also predicts the dependence on the pion mass of the leading-order hadronic contribution to the muon anomalous magnetic moment as the chiral limit is approached, this prediction turns out to be of no practical use because the physical pion mass is larger than the muon mass that sets the scale for the onset of this behavior.

Heavy and light flavor jet quenching at RHIC and LHC energies

NASA Astrophysics Data System (ADS)

Cao, Shanshan; Luo, Tan; Qin, Guang-You; Wang, Xin-Nian

2018-02-01

The Linear Boltzmann Transport (LBT) model coupled to hydrodynamical background is extended to include transport of both light partons and heavy quarks through the quark-gluon plasma (QGP) in high-energy heavy-ion collisions. The LBT model includes both elastic and inelastic medium-interaction of both primary jet shower partons and thermal recoil partons within perturbative QCD (pQCD). It is shown to simultaneously describe the experimental data on heavy and light flavor hadron suppression in high-energy heavy-ion collisions for different centralities at RHIC and LHC energies. More detailed investigations within the LBT model illustrate the importance of both initial parton spectra and the shapes of fragmentation functions on the difference between the nuclear modifications of light and heavy flavor hadrons. The dependence of the jet quenching parameter q ˆ on medium temperature and jet flavor is quantitatively extracted.

First measurement of chiral dynamics in π- γ → π- π- π+.

PubMed

Adolph, C; Alekseev, M G; Alexakhin, V Yu; Alexandrov, Yu; Alexeev, G D; Amoroso, A; Antonov, A A; Austregesilo, A; Badełek, B; Balestra, F; Barth, J; Baum, G; Bedfer, Y; Bernhard, J; Bertini, R; Bettinelli, M; Bicker, K A; Birsa, R; Bisplinghoff, J; Bordalo, P; Bradamante, F; Braun, C; Bravar, A; Bressan, A; Burtin, E; Chaberny, D; Chiosso, M; Chung, S U; Cicuttin, A; Crespo, M L; Dalla Torre, S; Das, S; Dasgupta, S S; Denisov, O Yu; Dhara, L; Donskov, S V; Doshita, N; Duic, V; Dünnweber, W; Dziewiecki, M; Efremov, A; Elia, C; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Finger, M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Garfagnini, R; Gautheron, F; Gavrichtchouk, O P; Gazda, R; Gerassimov, S; Geyer, R; Giorgi, M; Gnesi, I; Gobbo, B; Goertz, S; Grabmüller, S; Grasso, A; Grube, B; Gushterski, R; Guskov, A; Haas, F; von Harrach, D; Hasegawa, T; Heinsius, F H; Herrmann, F; Hess, C; Hinterberger, F; Horikawa, N; Höppner, Ch; d'Hose, N; Huber, S; Ishimoto, S; Ivanov, O; Ivanshin, Yu; Iwata, T; Jahn, R; Jasinski, P; Jegou, G; Joosten, R; Kabuss, E; Kang, D; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Klimaszewski, K; Koblitz, S; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Korzenev, A; Kotzinian, A M; Kouznetsov, O; Krämer, M; Kroumchtein, Z V; Kunne, F; Kurek, K; Lauser, L; Lednev, A A; Lehmann, A; Levorato, S; Lichtenstadt, J; Maggiora, A; Magnon, A; Makke, N; Mallot, G K; Mann, A; Marchand, C; Martin, A; Marzec, J; Massmann, F; Matsuda, T; Meyer, W; Michigami, T; Mikhailov, Yu V; Moinester, M A; Morreale, A; Mutter, A; Nagaytsev, A; Nagel, T; Nerling, F; Neubert, S; Neyret, D; Nikolaenko, V I; Nowak, W-D; Nunes, A S; Olshevsky, A G; Ostrick, M; Padee, A; Panknin, R; Panzieri, D; Parsamyan, B; Paul, S; Perevalova, E; Pesaro, G; Peshekhonov, D V; Piragino, G; Platchkov, S; Pochodzalla, J; Polak, J; Polyakov, V A; Pontecorvo, G; Pretz, J; Quintans, C; Rajotte, J-F; Ramos, S; Rapatsky, V; Reicherz, G; Richter, A; Rocco, E; Rondio, E; Rossiyskaya, N S; Ryabchikov, D I; Samoylenko, V D; Sandacz, A; Sapozhnikov, M G; Sarkar, S; Savin, I A; Sbrizzai, G; Schiavon, P; Schill, C; Schlüter, T; Schmitt, L; Schönning, K; Schopferer, S; Schröder, W; Shevchenko, O Yu; Siebert, H-W; Silva, L; Sinha, L; Sissakian, A N; Slunecka, M; Smirnov, G I; Sosio, S; Sozzi, F; Srnka, A; Stolarski, M; Sulc, M; Sulej, R; Sznajder, P; Takekawa, S; Ter Wolbeek, J; Tessaro, S; Tessarotto, F; Teufel, A; Tkatchev, L G; Uhl, S; Uman, I; Vandenbroucke, M; Virius, M; Vlassov, N V; Windmolders, R; Wiślicki, W; Wollny, H; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziembicki, M; Zhuravlev, N; Zvyagin, A

2012-05-11

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Update on flavoring-induced lung disease.

PubMed

Holden, Van K; Hines, Stella E

2016-03-01

Since the initial report of bronchiolitis obliterans in microwave popcorn workers, exposures to flavoring substances have been identified in a variety of food and flavor manufacturing facilities and in the consumer market. Attempts to decrease the risk of lung disease have included the use of flavoring substitutes; however, these chemicals may cause similar injury. This article reviews recent flavoring exposures and data on the pathogenesis, clinical characteristics, and surveillance of flavoring-induced lung disease. Diacetyl and 2,3-pentanedione exposures have occurred in food production facilities that make cookies, cereal, chocolate, and coffee. Airborne levels often exceed proposed occupational exposure limits. Cases of biopsy-proven bronchiolitis obliterans in heavy popcorn consumers have also been reported. New data demonstrate the presence of diacetyl and 2,3-pentanedione in flavored nicotine liquids used in electronic nicotine delivery systems. Diacetyl substitutes cause similar peri-bronchiolar fibrotic lesions in animal studies. Their use may continue to place workers at risk for flavoring-induced lung disease, which may present in forms beyond that of fixed airflow obstruction, contributing to delays in identifying and treating patients with flavoring-induced lung disease. Engineering controls, medical surveillance and personal protective equipment can limit flavorings exposure and risk for lung disease.

Probing neutrino and Higgs sectors in { SU(2) }_1 × { SU(2) }_2 × { U(1) }_Y model with lepton-flavor non-universality

NASA Astrophysics Data System (ADS)

Hue, L. T.; Arbuzov, A. B.; Ngan, N. T. K.; Long, H. N.

2017-05-01

The neutrino and Higgs sectors in the { SU(2) }_1 × { SU(2) }_2 × { U(1) }_Y model with lepton-flavor non-universality are discussed. We show that active neutrinos can get Majorana masses from radiative corrections, after adding only new singly charged Higgs bosons. The mechanism for the generation of neutrino masses is the same as in the Zee models. This also gives a hint to solving the dark matter problem based on similar ways discussed recently in many radiative neutrino mass models with dark matter. Except the active neutrinos, the appearance of singly charged Higgs bosons and dark matter does not affect significantly the physical spectrum of all particles in the original model. We indicate this point by investigating the Higgs sector in both cases before and after singly charged scalars are added into it. Many interesting properties of physical Higgs bosons, which were not shown previously, are explored. In particular, the mass matrices of charged and CP-odd Higgs fields are proportional to the coefficient of triple Higgs coupling μ . The mass eigenstates and eigenvalues in the CP-even Higgs sector are also presented. All couplings of the SM-like Higgs boson to normal fermions and gauge bosons are different from the SM predictions by a factor c_h, which must satisfy the recent global fit of experimental data, namely 0.995<|c_h|<1. We have analyzed a more general diagonalization of gauge boson mass matrices, then we show that the ratio of the tangents of the W-W' and Z-Z' mixing angles is exactly the cosine of the Weinberg angle, implying that number of parameters is reduced by 1. Signals of new physics from decays of new heavy fermions and Higgs bosons at LHC and constraints of their masses are also discussed.

F-theoretic vs microscopic description of a conformal mathcal{N} = 2 SYM theory

NASA Astrophysics Data System (ADS)

Billò, Marco; Gallot, Laurent; Lerda, Alberto; Pesando, Igor

2010-11-01

The F-theory background of four D7 branes in a type I' orientifold was conjectured to be described by the Seiberg-Witten curve for the superconformal SU(2) gauge theory with four flavors. This relation was explained by considering in this background a probe D3 brane, which supports this theory with SU(2) realized as Sp(1). Here we explicitly compute the non-perturbative corrections to the D7/D3 system in type I' due to D-instantons. This computation provides both the quartic effective action on the D7 branes and the quadratic effective action on the D3 brane; the latter agrees with the F-theoretic prediction. The action obtained in this way is related to the one derived from the usual instanton calculus à la Nekrasov (or from its AGT realization in terms of Liouville conformal blocks) by means of a non-perturbative redefinition of the coupling constant. We also point out an intriguing relation between the four-dimensional theory on the probe D3 brane with SO(8) flavor symmetry and the eight-dimensional dynamics on the D7 branes. On the latter, SO(8) represents a gauge group and the flavor masses correspond to the vacuum expectation values of an adjoint scalar field m: what we find is that the exact effective coupling in four dimensions is obtained from its perturbative part by taking into account in its mass dependence the full quantum dynamics of the field m in eight dimensions.

Acylation of Chiral Alcohols: A Simple Procedure for Chiral GC Analysis.

PubMed

Oromí-Farrús, Mireia; Torres, Mercè; Canela, Ramon

2012-01-01

The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α = 3.00) and 2-hexyl acetates (α = 1.95). This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC.

Forays in flavor

NASA Astrophysics Data System (ADS)

Perez, M. Jay

This dissertation is a summary of four works investigating questions of flavor in the Standard Model and Beyond. Drawing from the ideas of Grand Unification to unify quarks and leptons, the Seesaw Mechanism to explain the generation of neutrino masses, as well as the current data available from flavor observables, a framework called the "Flavor Ring" is introduced. Its aim is to bring as many theoretical tools to bear on the flavor puzzle of the Standard Model, providing additional constraints on Supersymmetric models of flavor which employ family symmetries. It is first applied to the Delta IW = 1/2 mass matrices of the quarks and charged leptons, where we use the additional constraints provided by the flavor ring and the family group Z7 x Z3 to perform a numerical search for phenomenologically allowed down-quark and charged lepton Yukawa matrices. Using the Seesaw Mechanism and relations from SO(10), we then consider the implications of the flavor ring framework on the DeltaIW = 0 Majorana mass M of right-handed neutrinos, and the Supersymmetric mu-mass matrix of a family of Higgs. We find a special form for M which predicts a normal hierarchy and the values of the light neutrino masses, and a mu-matrix with an incredible hierarchy of thirteen orders of magnitude. They are produced naturally by a simple underlying theory invariant under the family symmetry PSL2(7). We close with an examination of what role the additional heavy Higgs flavors may play in phenomenology, exploring a toy model where they serve as the messengers of Supersymmetry breaking.

Directing the phase behavior of polyelectrolyte complexes using chiral patterned peptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pacalin, Naomi M.; Leon, Lorraine; Tirrell, Matthew

Polyelectrolyte complexes (PECs) have a broad range of promising applications as soft materials due to their self-assembly and diversity of structure and chemical composition. Peptide polymer PECs are highly biocompatible and biodegradable, making them particularly useful for encapsulation of food additives and flavors, micellar drug delivery, medical and underwater adhesives, fetal membrane patches, and scaffolds for cell growth in tissue engineering. While parameters affecting PEC formation and stability in regards to charge effects are well researched, little is known about the effects of van der Waals interactions, hydrogen bonding, and secondary structure in these materials. Peptide chirality provides a uniquemore » opportunity to manipulate PEC phase to modulate the amount of solid-like (precipitate) or liquid-like (coacervate) character by influencing hydrogen bonding interactions among peptide chains. In previous work, we showed that chiral peptides form solid complexes, while complexes with even one racemic peptide were fluid. This raised the interesting question of how long a homochiral sequence must be to result in solid phase formation. In this work, we designed chiral patterned peptides of polyglutamic acid and polylysine ranging from 50 to 90% L-chiral residues with increasing numbers of sequential L-chiral residues before a chirality change. These polymers were mixed together to form PECs. We observed that 8 or more sequential L-chiral residues are necessary to achieve both the appearance of a precipitate phase and sustained beta-sheets in the complex, as determined by optical imaging and FTIR Spectroscopy. Less homochiral content results in formation of a coacervate phase. Thus, we show that chiral sequence can be used to control the phase transition of PECs. Understanding how to manipulate PEC phase using chiral sequence as presented here may enable tuning of the material properties to achieve the desired mechanical strength for coatings and

Directing the phase behavior of polyelectrolyte complexes using chiral patterned peptides

NASA Astrophysics Data System (ADS)

Pacalin, Naomi M.; Leon, Lorraine; Tirrell, Matthew

2016-10-01

Polyelectrolyte complexes (PECs) have a broad range of promising applications as soft materials due to their self-assembly and diversity of structure and chemical composition. Peptide polymer PECs are highly biocompatible and biodegradable, making them particularly useful for encapsulation of food additives and flavors, micellar drug delivery, medical and underwater adhesives, fetal membrane patches, and scaffolds for cell growth in tissue engineering. While parameters affecting PEC formation and stability in regards to charge effects are well researched, little is known about the effects of van der Waals interactions, hydrogen bonding, and secondary structure in these materials. Peptide chirality provides a unique opportunity to manipulate PEC phase to modulate the amount of solid-like (precipitate) or liquid-like (coacervate) character by influencing hydrogen bonding interactions among peptide chains. In previous work, we showed that chiral peptides form solid complexes, while complexes with even one racemic peptide were fluid. This raised the interesting question of how long a homochiral sequence must be to result in solid phase formation. In this work, we designed chiral patterned peptides of polyglutamic acid and polylysine ranging from 50 to 90% L-chiral residues with increasing numbers of sequential L-chiral residues before a chirality change. These polymers were mixed together to form PECs. We observed that 8 or more sequential L-chiral residues are necessary to achieve both the appearance of a precipitate phase and sustained β-sheets in the complex, as determined by optical imaging and FTIR Spectroscopy. Less homochiral content results in formation of a coacervate phase. Thus, we show that chiral sequence can be used to control the phase transition of PECs. Understanding how to manipulate PEC phase using chiral sequence as presented here may enable tuning of the material properties to achieve the desired mechanical strength for coatings and polymer

Flavors and Risk: Perceptions of Flavors in Little Cigars and Cigarillos Among U.S. Adults, 2015.

PubMed

Nyman, Amy L; Sterling, Kymberle L; Majeed, Ban A; Jones, Dina M; Eriksen, Michael P

2017-06-28

Flavored little cigars, cigarillos, and filtered cigars (LCCs) are popular and pose unique health risks. This study explored risk perceptions of flavors in LCCs and the relationship between perceptions and use among U.S. adults. Data were from the 2015 Tobacco Products and Risk Perceptions Survey of a national probability sample of 6,051 adults, conducted online, August-September, 2015. The analytic sample consisted of 5,105 adults aware of LCCs and 2,174 who had ever used any type of LCCs. Just over half of adults reported flavors in LCCs as "very" or "somewhat" risky, while more than one-third of adults reported they didn't know the risks of flavors in LCCs. Younger adults, males, and users of any LCCs were more likely than older adults, females and non-users, respectively, to perceive LCC flavors as less risky. Those who perceived LCC flavors as "not at all risky" or "a little risky" were roughly twice as likely to have ever used flavored LCCs compared to those who reported not knowing the risks (AOR=2.07, 95% CI=1.16, 3.69 and AOR=1.96, 95% CI=1.26, 3.06). Those who reported LCC flavors as "very risky" were also more likely to have ever used flavored LCCs than those who reported not knowing the risks (AOR=1.50, 95% CI=1.13, 1.98). Though the proportion of adults assigning low risk to flavors in LCCs is small, these adults are more likely to use flavored LCCs. The association of use with risk perceptions of flavors in LCCs should be addressed in health risk campaigns. Flavored LCCs are popular, particularly among young adults. While understanding the impact of flavors is an FDA research priority, little is currently known about perceptions of risk associated with flavors in LCCs. This study explores the nature of risk perceptions of flavors in LCCs, and the relationship between perceptions and flavored LCC use. We conclude that perception of risk of flavors in LCCs is related to use of these products, particularly perception of less risk. Considering the

Proper time regularization and the QCD chiral phase transition

PubMed Central

Cui, Zhu-Fang; Zhang, Jin-Li; Zong, Hong-Shi

2017-01-01

We study the QCD chiral phase transition at finite temperature and finite quark chemical potential within the two flavor Nambu–Jona-Lasinio (NJL) model, where a generalization of the proper-time regularization scheme is motivated and implemented. We find that in the chiral limit the whole transition line in the phase diagram is of second order, whereas for finite quark masses a crossover is observed. Moreover, if we take into account the influence of quark condensate to the coupling strength (which also provides a possible way of how the effective coupling varies with temperature and quark chemical potential), it is found that a CEP may appear. These findings differ substantially from other NJL results which use alternative regularization schemes, some explanation and discussion are given at the end. This indicates that the regularization scheme can have a dramatic impact on the study of the QCD phase transition within the NJL model. PMID:28401889

Semilocal momentum-space regularized chiral two-nucleon potentials up to fifth order

NASA Astrophysics Data System (ADS)

Reinert, P.; Krebs, H.; Epelbaum, E.

2018-05-01

We introduce new semilocal two-nucleon potentials up to fifth order in the chiral expansion. We employ a simple regularization approach for the pion exchange contributions which i) maintains the long-range part of the interaction, ii) is implemented in momentum space and iii) can be straightforwardly applied to regularize many-body forces and current operators. We discuss in detail the two-nucleon contact interactions at fourth order and demonstrate that three terms out of fifteen used in previous calculations can be eliminated via suitably chosen unitary transformations. The removal of the redundant contact terms results in a drastic simplification of the fits to scattering data and leads to interactions which are much softer ( i.e., more perturbative) than our recent semilocal coordinate-space regularized potentials. Using the pion-nucleon low-energy constants from matching pion-nucleon Roy-Steiner equations to chiral perturbation theory, we perform a comprehensive analysis of nucleon-nucleon scattering and the deuteron properties up to fifth chiral order and study the impact of the leading F-wave two-nucleon contact interactions which appear at sixth order. The resulting chiral potentials at fifth order lead to an outstanding description of the proton-proton and neutron-proton scattering data from the self-consistent Granada-2013 database below the pion production threshold, which is significantly better than for any other chiral potential. For the first time, the chiral potentials match in precision and even outperform the available high-precision phenomenological potentials, while the number of adjustable parameters is, at the same time, reduced by about ˜ 40%. Last but not least, we perform a detailed error analysis and, in particular, quantify for the first time the statistical uncertainties of the fourth- and the considered sixth-order contact interactions.

A non-perturbative exploration of the high energy regime in Nf=3 QCD. ALPHA Collaboration

NASA Astrophysics Data System (ADS)

Dalla Brida, Mattia; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer

2018-05-01

Using continuum extrapolated lattice data we trace a family of running couplings in three-flavour QCD over a large range of scales from about 4 to 128 GeV. The scale is set by the finite space time volume so that recursive finite size techniques can be applied, and Schrödinger functional (SF) boundary conditions enable direct simulations in the chiral limit. Compared to earlier studies we have improved on both statistical and systematic errors. Using the SF coupling to implicitly define a reference scale 1/L_0≈ 4 GeV through \\bar{g}^2(L_0) =2.012, we quote L_0 Λ ^{N_f=3}_{{\\overline{MS}}} =0.0791(21). This error is dominated by statistics; in particular, the remnant perturbative uncertainty is negligible and very well controlled, by connecting to infinite renormalization scale from different scales 2^n/L_0 for n=0,1,\\ldots ,5. An intermediate step in this connection may involve any member of a one-parameter family of SF couplings. This provides an excellent opportunity for tests of perturbation theory some of which have been published in a letter (ALPHA collaboration, M. Dalla Brida et al. in Phys Rev Lett 117(18):182001, 2016). The results indicate that for our target precision of 3 per cent in L_0 Λ ^{N_f=3}_{{\\overline{MS}}}, a reliable estimate of the truncation error requires non-perturbative data for a sufficiently large range of values of α _s=\\bar{g}^2/(4π ). In the present work we reach this precision by studying scales that vary by a factor 2^5= 32, reaching down to α _s≈ 0.1. We here provide the details of our analysis and an extended discussion.

To Flavor or Not to Flavor Extemporaneous Omeprazole Liquid.

PubMed

Chuong, Monica C; Taglieri, Catherine A; Kerr, Stephen G

2017-01-01

Omeprazole is a proton pump inhibitor used to treat the symptoms of gastro esophageal reflux disease, ulcers, excess stomach acid, infection with Helicobacter pylori, and to control the gastric side effects of various drugs. The approved dosage forms in the U.S. are powder in compounding kits, delayed-release granules for oral suspension, oral delayed-release tablets, and oral delayed-release capsules. An extemporaneously compounded unsweetened oral liquid method, published in the International Journal of Pharmaceutical Compounding, was found to be commonly used by pharmacists. This project investigated the robustness of the compendium omeprazole high-performance liquid chromatographic assay in evaluating an oral liquid made from commercial delayed-release pellets, the potency of extemporaneously compounded solutions having a 1.125% v/v flavored versus unflavored samples stored at controlled cold temperatures at different time points, and examining the absorption spectrum of the flavoring agent. As part of the study, stability-indication testing was also conducted. The studies indicate that the chromatographic area under the plasma concentration-time curve of both study groups remained over 90% of the label claim during the follow-up period. The flavor did not significantly impact the pH of the oral liquid. This study further identified (1) an increase in resilient foam formation in the flavored liquid, potentially hindering dosing accuracy, (2) omeprazole is oxidized easily by 3% hydrogen peroxide, and (3) flavoring agent absorbs in an ultraviolet visible spectroscopy spectral range often used in assay detectors for quantification of drug molecules, and could interfere with assay protocols of the same. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Baryon masses and σ terms in SU(3) BChPT × 1/Nc

NASA Astrophysics Data System (ADS)

Fernando, I. P.; Alarcón, J. M.; Goity, J. L.

2018-06-01

Baryon masses and nucleon σ terms are studied with the effective theory that combines the chiral and 1 /Nc expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the σ term associated with the scalar density u bar u + d bar d - 2 s bar s is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a σ term puzzle. It is shown that while the nucleon σ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Adding to the analysis lattice QCD baryon masses, it is found that σπN = 69 (10) MeV and σs has natural magnitude within its relatively large uncertainty.

Chiral current generation in QED by longitudinal photons

NASA Astrophysics Data System (ADS)

Acosta Avalo, J. L.; Pérez Rojas, H.

2016-08-01

We report the generation of a pseudovector electric current having imbalanced chirality in an electron-positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler-Bell-Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone) contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone). In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

Chiral Cliffs: Investigating the Influence of Chirality on Binding Affinity.

PubMed

Schneider, Nadine; Lewis, Richard A; Fechner, Nikolas; Ertl, Peter

2018-05-11

Chirality is understood by many as a binary concept: a molecule is either chiral or it is not. In terms of the action of a structure on polarized light, this is indeed true. When examined through the prism of molecular recognition, the answer becomes more nuanced. In this work, we investigated chiral behavior on protein-ligand binding: when does chirality make a difference in binding activity? Chirality is a property of the 3D structure, so recognition also requires an appreciation of the conformation. In many situations, the bioactive conformation is undefined. We set out to address this by defining and using several novel 2D descriptors to capture general characteristic features of the chiral center. Using machine-learning methods, we built different predictive models to estimate if a chiral pair (a set of two enantiomers) might exhibit a chiral cliff in a binding assay. A set of about 3800 chiral pairs extracted from the ChEMBL23 database was used to train and test our models. By achieving an accuracy of up to 75 %, our models provide good performance in discriminating chiral cliffs from non-cliffs. More importantly, we were able to derive some simple guidelines for when one can reasonably use a racemate and when an enantiopure compound is needed in an assay. We critically discuss our results and show detailed examples of using our guidelines. Along with this publication we provide our dataset, our novel descriptors, and the Python code to rebuild the predictive models. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Chiral Separation Effect in quenched finite-density QCD

NASA Astrophysics Data System (ADS)

Puhr, Matthias; Buividovich, Pavel

2018-03-01

We present results of a study of the Chiral Separation Effect (CSE) in quenched finite-density QCD. Using a recently developed numerical method we calculate the conserved axial current for exactly chiral overlap fermions at finite density for the first time. We compute the anomalous transport coeffcient for the CSE in the confining and deconfining phase and investigate possible deviations from the universal value. In both phases we find that non-perturbative corrections to the CSE are absent and we reproduce the universal value for the transport coeffcient within small statistical errors. Our results suggest that the CSE can be used to determine the renormalisation factor of the axial current.

Heavy and light flavor jet quenching at RHIC and LHC energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Shanshan; Luo, Tan; Qin, Guang-You

The Linear Boltzmann Transport (LBT) model coupled to hydrodynamical background is extended to include transport of both light partons and heavy quarks through the quark–gluon plasma (QGP) in high-energy heavy-ion collisions. The LBT model includes both elastic and inelastic medium-interaction of both primary jet shower partons and thermal recoil partons within perturbative QCD (pQCD). It is shown to simultaneously describe the experimental data on heavy and light flavor hadron suppression in high-energy heavy-ion collisions for different centralities at RHIC and LHC energies. More detailed investigations within the LBT model illustrate the importance of both initial parton spectra and the shapes of fragmentation functions on the difference between the nuclear modifications of light and heavy flavor hadrons. Finally, the dependence of the jet quenching parametermore » $$\\hat{q}$$ on medium temperature and jet flavor is quantitatively extracted.« less

Heavy and light flavor jet quenching at RHIC and LHC energies

DOE PAGES

Cao, Shanshan; Luo, Tan; Qin, Guang-You; ...

2017-12-14

The Linear Boltzmann Transport (LBT) model coupled to hydrodynamical background is extended to include transport of both light partons and heavy quarks through the quark–gluon plasma (QGP) in high-energy heavy-ion collisions. The LBT model includes both elastic and inelastic medium-interaction of both primary jet shower partons and thermal recoil partons within perturbative QCD (pQCD). It is shown to simultaneously describe the experimental data on heavy and light flavor hadron suppression in high-energy heavy-ion collisions for different centralities at RHIC and LHC energies. More detailed investigations within the LBT model illustrate the importance of both initial parton spectra and the shapes of fragmentation functions on the difference between the nuclear modifications of light and heavy flavor hadrons. Finally, the dependence of the jet quenching parametermore » $$\\hat{q}$$ on medium temperature and jet flavor is quantitatively extracted.« less

The flavor-locked flavorful two Higgs doublet model

NASA Astrophysics Data System (ADS)

Altmannshofer, Wolfgang; Gori, Stefania; Robinson, Dean J.; Tuckler, Douglas

2018-03-01

We propose a new framework to generate the Standard Model (SM) quark flavor hierarchies in the context of two Higgs doublet models (2HDM). The `flavorful' 2HDM couples the SM-like Higgs doublet exclusively to the third quark generation, while the first two generations couple exclusively to an additional source of electroweak symmetry breaking, potentially generating striking collider signatures. We synthesize the flavorful 2HDM with the `flavor-locking' mechanism, that dynamically generates large quark mass hierarchies through a flavor-blind portal to distinct flavon and hierarchon sectors: dynamical alignment of the flavons allows a unique hierarchon to control the respective quark masses. We further develop the theoretical construction of this mechanism, and show that in the context of a flavorful 2HDM-type setup, it can automatically achieve realistic flavor structures: the CKM matrix is automatically hierarchical with | V cb | and | V ub | generically of the observed size. Exotic contributions to meson oscillation observables may also be generated, that may accommodate current data mildly better than the SM itself.

Stability of warped AdS3 vacua of topologically massive gravity

NASA Astrophysics Data System (ADS)

Anninos, Dionysios; Esole, Mboyo; Guica, Monica

2009-10-01

AdS3 vacua of topologically massive gravity (TMG) have been shown to be perturbatively unstable for all values of the coupling constant except the chiral point μl = 1. We study the possibility that the warped vacua of TMG, which exist for all values of μ, are stable under linearized perturbations. In this paper, we show that spacelike warped AdS3 vacua with Compère-Detournay boundary conditions are indeed stable in the range μl>3. This is precisely the range in which black hole solutions arise as discrete identifications of the warped AdS3 vacuum. The situation somewhat resembles chiral gravity: although negative energy modes do exist, they are all excluded by the boundary conditions, and the perturbative spectrum solely consists of boundary (pure large gauge) gravitons.

Sucrose-conditioned flavor preferences in sweet ageusic T1r3 and Calhm1 knockout mice.

PubMed

Sclafani, Anthony; Marambaud, Philippe; Ackroff, Karen

2014-03-14

The present study compared the ability of sweet ageusic T1r3 knockout (KO) and Calhm1 KO mice to acquire preferences for a sucrose-paired flavor as well as for unflavored sucrose. The KO and wildtype (WT) mice were given 24-h one-bottle access to 8% sucrose containing one flavor CS+, e.g., grape) and to water containing a different flavor (CS-, e.g., cherry) over 4 training days. In subsequent two-bottle tests with the flavors in water only, the T1r3 KO and Calhm1 KO mice, like WT mice, preferred the CS+ to the CS-. After training with flavored solutions, both KO groups also preferred unflavored 8% sucrose to water although Calhm1 KO mice required more sugar experience to match the preference of the T1r3 KO mice. These findings demonstrate that Calhm1 KO mice, like T1r3 KO mice and WT mice, are sensitive to the post-oral preference conditioning actions of sucrose and can discriminate sugar from water. Yet, despite their acquired sucrose preferences, the Calhm1 KO and T1r3 KO mice consumed only half as much sugar per day as did WT mice. Thus, sweet taste signaling elements are not needed in the gut for sugar conditioning, but sweet taste signaling in the mouth is essential for the full expression of sugar appetite. Copyright © 2013 Elsevier Inc. All rights reserved.

Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality.

PubMed

Chen, Ting; Li, Shu-Ying; Wang, Dong; Wan, Li-Jun

2017-11-01

Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction-mediated chirality induction and the intrinsic stereogenic center-controlled chirality induction in a two-dimensional (2D) molecular assembly at the liquid/solid interface. Two enantiomorphous honeycomb networks are formed by the coassembly of an achiral 5-(benzyloxy)isophthalic acid (BIC) derivative and 1-octanol at the liquid/solid interface. The preferential formation of the globally homochiral assembly can be achieved either by using the chiral analog of 1-octanol, ( S )-6-methyl-1-octanol, as a chiral coadsorber to induce chirality to the BIC assembly via noncovalent hydrogen bonding or by covalently linking a chiral center in the side chain of BIC. Both the chiral coadsorber and the intrinsically chiral BIC derivative can act as a chiral seeds to induce a preferred handedness in the assembly of the achiral BIC derivatives. Furthermore, the noncovalent interaction-mediated chirality induction can restrain or even overrule the manifestation of the intrinsic chirality of the BIC molecule and dominate the handedness of the 2D molecular coassembly. This study provides insight into the interplay of intrinsically chiral centers and external chiral coadsorbers in the chiral induction, transfer, and amplification processes of 2D molecular assembly.

Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality

PubMed Central

Chen, Ting; Li, Shu-Ying; Wang, Dong; Wan, Li-Jun

2017-01-01

Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction–mediated chirality induction and the intrinsic stereogenic center–controlled chirality induction in a two-dimensional (2D) molecular assembly at the liquid/solid interface. Two enantiomorphous honeycomb networks are formed by the coassembly of an achiral 5-(benzyloxy)isophthalic acid (BIC) derivative and 1-octanol at the liquid/solid interface. The preferential formation of the globally homochiral assembly can be achieved either by using the chiral analog of 1-octanol, (S)-6-methyl-1-octanol, as a chiral coadsorber to induce chirality to the BIC assembly via noncovalent hydrogen bonding or by covalently linking a chiral center in the side chain of BIC. Both the chiral coadsorber and the intrinsically chiral BIC derivative can act as a chiral seeds to induce a preferred handedness in the assembly of the achiral BIC derivatives. Furthermore, the noncovalent interaction–mediated chirality induction can restrain or even overrule the manifestation of the intrinsic chirality of the BIC molecule and dominate the handedness of the 2D molecular coassembly. This study provides insight into the interplay of intrinsically chiral centers and external chiral coadsorbers in the chiral induction, transfer, and amplification processes of 2D molecular assembly. PMID:29119137

Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

DOE PAGES

Kalaydzhyan, Tigran; Murchikova, Elena

2017-03-24

In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium 3He-A, neutron stars and the Early Universe. Here, we study first-order hy-drodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiralmore » magnetic waves) and transverse velocity (chiral Alfvén wave). We also demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.« less

The running coupling of the minimal sextet composite Higgs model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fodor, Zoltan; Holland, Kieran; Kuti, Julius

We compute the renormalized running coupling of SU(3) gauge theory coupled to N f = 2 flavors of massless Dirac fermions in the 2-index-symmetric (sextet) representation. This model is of particular interest as a minimal realization of the strongly interacting composite Higgs scenario. A recently proposed finite volume gradient flow scheme is used. The calculations are performed at several lattice spacings with two different implementations of the gradient flow allowing for a controlled continuum extrapolation and particular attention is paid to estimating the systematic uncertainties. For small values of the renormalized coupling our results for the β-function agree with perturbation theory. For moderate couplings we observe a downward deviation relative to the 2-loop β-function but in the coupling range where the continuum extrapolation is fully under control we do not observe an infrared fixed point. The explored range includes the locations of the zero of the 3-loop and the 4-loop β-functions in themore » $$\\overline{MS}$$ scheme. The absence of a non-trivial zero in the β-function in the explored range of the coupling is consistent with our earlier findings based on hadronic observables, the chiral condensate and the GMOR relation. The present work is the first to report continuum non-perturbative results for the sextet model.« less

One-loop perturbative coupling of A and A⊙ through the chiral overlap operator

NASA Astrophysics Data System (ADS)

Makino, Hiroki; Morikawa, Okuto; Suzuki, Hiroshi

2017-06-01

We study the one-loop effective action defined by the chiral overlap operator in the four-dimensional lattice formulation of chiral gauge theories by Grabowska and Kaplan. In the tree-level continuum limit, the left-handed component of the fermion is coupled only to the original gauge field A, while the right-handed one is coupled only to A_\\star, which is given by the gradient flow of A with infinite flow time. In this paper, we show that the continuum limit of the one-loop effective action contains local interaction terms between A and A_\\star, which do not generally vanish even if the gauge representation of the fermion is anomaly free. We argue that the presence of such interaction terms can be regarded as undesired gauge symmetry-breaking effects in the formulation.

QCD Coupling from a Nonperturbative Determination of the Three-Flavor Λ Parameter

DOE PAGES

Bruno, Mattia; Brida, Mattia Dalla; Fritzsch, Patrick; ...

2017-09-08

We present a lattice determination of the Λ parameter in three-flavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from 0.2 to 70 GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain Λ(3)MS=341(12) MeV. The nonperturbative running up to very high energies guarantees that systematic effects associated with perturbation theory are well under control. Using the four-loop prediction for Λ(5)MS/Λ(3)MS yields α(5)MS(mZ)=0.11852(84).

Minimal S U ( 3 ) × S U ( 3 ) symmetry breaking patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Yang; Dobrescu, Bogdan A.

Here, we study the vacua of anmore » $$SU(3)\\times SU(3)$$-symmetric model with a bifundamental scalar. Structures of this type appear in various gauge theories such as the Renormalizable Coloron Model, which is an extension of QCD, or the Trinification extension of the electroweak group. In other contexts, such as chiral symmetry, $$SU(3)\\times SU(3)$$ is a global symmetry. As opposed to more general $$SU(N)\\times SU(N)$$ symmetric models, the $N=3$ case is special due to the presence of a trilinear scalar term in the potential. We find that the most general tree-level potential has only three types of minima: one that preserves the diagonal $SU(3)$ subgroup, one that is $$SU(2)\\times SU(2)\\times U(1)$$ symmetric, and a trivial one where the full symmetry remains unbroken. The phase diagram is complicated, with some regions where there is a unique minimum, and other regions where two minima coexist.« less

Minimal S U ( 3 ) × S U ( 3 ) symmetry breaking patterns

DOE PAGES

Bai, Yang; Dobrescu, Bogdan A.

2018-03-16

Here, we study the vacua of anmore » $$SU(3)\\times SU(3)$$-symmetric model with a bifundamental scalar. Structures of this type appear in various gauge theories such as the Renormalizable Coloron Model, which is an extension of QCD, or the Trinification extension of the electroweak group. In other contexts, such as chiral symmetry, $$SU(3)\\times SU(3)$$ is a global symmetry. As opposed to more general $$SU(N)\\times SU(N)$$ symmetric models, the $N=3$ case is special due to the presence of a trilinear scalar term in the potential. We find that the most general tree-level potential has only three types of minima: one that preserves the diagonal $SU(3)$ subgroup, one that is $$SU(2)\\times SU(2)\\times U(1)$$ symmetric, and a trivial one where the full symmetry remains unbroken. The phase diagram is complicated, with some regions where there is a unique minimum, and other regions where two minima coexist.« less

Reducing democratic type II supergravity on SU(3) × SU(3) structures

NASA Astrophysics Data System (ADS)

Cassani, Davide

2008-06-01

Type II supergravity on backgrounds admitting SU(3) × SU(3) structure and general fluxes is considered. Using the generalized geometry formalism, we study dimensional reductions leading to N = 2 gauged supergravity in four dimensions, possibly with tensor multiplets. In particular, a geometric formula for the full N = 2 scalar potential is given. Then we implement a truncation ansatz, and derive the complete N = 2 bosonic action. While the NSNS contribution is obtained via a direct dimensional reduction, the contribution of the RR sector is computed starting from the democratic formulation and demanding consistency with the reduced equations of motion.

Chiral Gold Nanoclusters: Atomic Level Origins of Chirality.

PubMed

Zeng, Chenjie; Jin, Rongchao

2017-08-04

Chiral nanomaterials have received wide interest in many areas, but the exact origin of chirality at the atomic level remains elusive in many cases. With recent significant progress in atomically precise gold nanoclusters (e.g., thiolate-protected Au n (SR) m ), several origins of chirality have been unveiled based upon atomic structures determined by using single-crystal X-ray crystallography. The reported chiral Au n (SR) m structures explicitly reveal a predominant origin of chirality that arises from the Au-S chiral patterns at the metal-ligand interface, as opposed to the chiral arrangement of metal atoms in the inner core (i.e. kernel). In addition, chirality can also be introduced by a chiral ligand, manifested in the circular dichroism response from metal-based electronic transitions other than the ligand's own transition(s). Lastly, the chiral arrangement of carbon tails of the ligands has also been discovered in a very recent work on chiral Au 133 (SR) 52 and Au 246 (SR) 80 nanoclusters. Overall, the origins of chirality discovered in Au n (SR) m nanoclusters may provide models for the understanding of chirality origins in other types of nanomaterials and also constitute the basis for the development of various applications of chiral nanoparticles. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Specific heat of the chiral-soliton-lattice phase in Yb(Ni0.94Cu0.06)3Al9

NASA Astrophysics Data System (ADS)

Ninomiya, Hiroki; Sato, Takaaki; Inoue, Katsuya; Ohara, Shigeo

2018-05-01

We have studied the monoaxial-chiral helimagnet YbNi3Al9 and its-substituted analogue Yb(Ni0.94Cu0.06)3Al9. These compounds belong to a chiral space group R32. In Yb(Ni0.94Cu0.06)3Al9 with the magnetic ordering temperature TM = 6.4 K , only when the magnetic field is applied perpendicular to the helical axis, the chiral soliton lattice is observed below Hc = 10 kOe . YbNi3Al9 with TM = 3.4 K exhibits a metamagnetic transition at Hc = 1 kOe in 2 K. To study the formation of chiral helimagnetic state and chiral soliton lattice, we have measured the specific heat in magnetic fields applied parallel and perpendicular to the helical axis. In zero field, with decreasing temperature, specific heat shows λ-type phase transition from paramagnetic state to chiral helimagnetic one. At the temperature where the chiral soliton lattice emerges, we have found that the specific heat shows a sharp peak. In addition, at around the crossover between paramagnetic state and forced-ferromagnetic one, a broad maximum has been observed. We have determined the magnetic phase diagrams of YbNi3Al9 and Yb(Ni0.94Cu0.06)3Al9.

Sigma decomposition: the CP-odd Lagrangian

NASA Astrophysics Data System (ADS)

Hierro, I. M.; Merlo, L.; Rigolin, S.

2016-04-01

In Alonso et al., JHEP 12 (2014) 034, the CP-even sector of the effective chiral Lagrangian for a generic composite Higgs model with a symmetric coset has been constructed, up to four momenta. In this paper, the CP-odd couplings are studied within the same context. If only the Standard Model bosonic sources of custodial symmetry breaking are considered, then at most six independent operators form a basis. One of them is the weak- θ term linked to non-perturbative sources of CP violation, while the others describe CP-odd perturbative couplings between the Standard Model gauge bosons and an Higgs-like scalar belonging to the Goldstone boson sector. The procedure is then applied to three distinct exemplifying frameworks: the original SU(5)/SO(5) Georgi-Kaplan model, the minimal custodial-preserving SO(5)/SO(4) model and the minimal SU(3)/(SU(2) × U(1)) model, which intrinsically breaks custodial symmetry. Moreover, the projection of the high-energy electroweak effective theory to the low-energy chiral effective Lagrangian for a dynamical Higgs is performed, uncovering strong relations between the operator coefficients and pinpointing the differences with the elementary Higgs scenario.

Studying the Perturbed Wess-Zumino-Novikov-Witten SU(2) k Theory Using the Truncated Conformal Spectrum Approach

DOE PAGES

Konik, R. M.; Palmai, T.; Takacs, G.; ...

2015-08-24

We study the SU(2) k Wess-Zumino-Novikov-Witten (WZNW) theory perturbed by the trace of the primary field in the adjoint representation, a theory governing the low-energy behaviour of a class of strongly correlated electronic systems. While the model is non-integrable, its dynamics can be investigated using the numerical technique of the truncated conformal spectrum approach combined with numerical and analytical renormalization groups (TCSA+RG). The numerical results so obtained provide support for a semiclassical analysis valid at k » 1. Namely, we find that the low energy behavior is sensitive to the sign of the coupling constant, λ. Moreover for λ >more » 0 this behavior depends on whether k is even or odd. With k even, we find definitive evidence that the model at low energies is equivalent to the massive O(3) sigma model. For k odd, the numerical evidence is more equivocal, but we find indications that the low energy effective theory is critical.« less

Baryon masses and σ terms in SU(3) BChPT×1/N c

DOE PAGES

Fernando, Ishara P.; Alarcon-Soriano, Jose-Manuel; Goity, Jose Luis

2018-04-27

Baryon masses and nucleonmore » $$\\sigma$$ terms are studied with the effective theory that combines the chiral and $$1/N_c$$ expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the $$\\sigma$$ term associated with the scalar density $$\\bar u u+\\bar d d-2\\bar s s$$ is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a $$\\sigma$$ term puzzle. It is shown that while the nucleon $$\\sigma$$ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Lastly, adding to the analysis lattice QCD baryon masses, it is found that $$\\sigma_{\\pi N}=69(10)$$~MeV and $$\\sigma_s$$ has natural magnitude within its relative large uncertainty.« less

Baryon masses and σ terms in SU(3) BChPT×1/N c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernando, Ishara P.; Alarcon-Soriano, Jose-Manuel; Goity, Jose Luis

Baryon masses and nucleonmore » $$\\sigma$$ terms are studied with the effective theory that combines the chiral and $$1/N_c$$ expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the $$\\sigma$$ term associated with the scalar density $$\\bar u u+\\bar d d-2\\bar s s$$ is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a $$\\sigma$$ term puzzle. It is shown that while the nucleon $$\\sigma$$ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Lastly, adding to the analysis lattice QCD baryon masses, it is found that $$\\sigma_{\\pi N}=69(10)$$~MeV and $$\\sigma_s$$ has natural magnitude within its relative large uncertainty.« less

Chiral Magnetic Effect in Condensed Matters

NASA Astrophysics Data System (ADS)

Li, Qiang

The chiral magnetic effect is the generation of electrical current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum chiral anomaly in systems possessing charged chiral fermions. In quark-gluon plasma containing nearly massless quarks, the chirality imbalance is sourced by the topological transitions. In condensed matter systems, the chiral quasiparticles emerge in the 3D Dirac and Weyl semimetals having a linear dispersion relation. Recently, the chiral magnetic effect was discovered in a 3D Dirac semimetal - zirconium pentatelluride, ZrTe5, in which a large negative magnetoresistance is observed when magnetic field is parallel with the current. It is now reported in more than a dozen Dirac and Weyl semimetals. Broadly speaking, the chiral magnetic effect can exist in a variety of condensed matters. In some cases, a material may be transformed into a Weyl semimetal by magnetic field, exhibiting the chiral magnetic effect. In other cases, the chiral magnetic current may be generated in magnetic Dirac semimetals without external magnetic field, or in asymmetric Weyl semimetals without electric field where only a magnetic field and the source of chiral quasipartiles would be necessary. In the limit of conserved quasiparticle chirality, charge transport by the chiral magnetic current is non-dissipative. The powerful notion of chirality, originally discovered in high-energy and nuclear physics, holds promise in new ways of transmitting and processing information and energy. At the same time, chiral materials have opened a fascinating possibility to study the quantum dynamics of relativistic field theory in condensed matter experiments.

Dark matter and gauged flavor symmetries

DOE PAGES

Bishara, Fady; Greljo, Admir; Kamenik, Jernej F.; ...

2015-12-21

We investigate the phenomenology of flavored dark matter (DM). DM stability is guaranteed by an accidental Z 3 symmetry, a subgroup of the standard model (SM) flavor group that is not broken by the SM Yukawa interactions. We consider an explicit realization where the quark part of the SM flavor group is fully gauged. If the dominant interactions between DM and visible sector are through flavor gauge bosons, as we show for Dirac fermion flavored DM, then the DM mass is bounded between roughly 0.5 TeV and 5 TeV if the DM multiplet mass is split only radiatively. In general,more » however, no such relation exists. We demonstrate this using scalar flavored DM where the main interaction with the SM is through the Higgs portal. For both cases we derive constraints from flavor, cosmology, direct and indirect DM detection, and collider searches.« less

Dark matter and gauged flavor symmetries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishara, Fady; Greljo, Admir; Kamenik, Jernej F.

We investigate the phenomenology of flavored dark matter (DM). DM stability is guaranteed by an accidental Z 3 symmetry, a subgroup of the standard model (SM) flavor group that is not broken by the SM Yukawa interactions. We consider an explicit realization where the quark part of the SM flavor group is fully gauged. If the dominant interactions between DM and visible sector are through flavor gauge bosons, as we show for Dirac fermion flavored DM, then the DM mass is bounded between roughly 0.5 TeV and 5 TeV if the DM multiplet mass is split only radiatively. In general,more » however, no such relation exists. We demonstrate this using scalar flavored DM where the main interaction with the SM is through the Higgs portal. For both cases we derive constraints from flavor, cosmology, direct and indirect DM detection, and collider searches.« less

Gelation induced supramolecular chirality: chirality transfer, amplification and application.

PubMed

Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

2014-08-14

Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

Emission of diacetyl (2,3 butanedione) from natural butter, microwave popcorn butter flavor powder, paste, and liquid products.

PubMed

Rigler, Mark W; Longo, William E

2010-01-01

Diacetyl (2,3 butanedione), a butter-flavored diketone, has been linked to a severe lung disease, bronchiolitis obliterans. We tested a total of three natural butters and artificial microwave popcorn butter flavorings (three powders, two pastes, and one liquid) for bulk diacetyl concentration and diacetyl emissions when heated. Pastes and liquid butter flavors contained the highest amount (6% to 10.6%) while natural butter possessed up to 7500 times less diacetyl. All artificial butter flavors studied emitted diacetyl. Dry powders emitted up to 1.62 ppm diacetyl; wetted powders up to 54.7 ppm diacetyl; and pastes emitted up to 34.9 ppm diacetyl. The liquid butter flavor emitted up to 17.2 ppm diacetyl. Microwave popcorn flavoring mixtures emitted up to 11.4 ppm diacetyl. At least 93% of the dry powder particles were inhalable. These studies show that microwave butter flavoring products generate concentrations of diacetyl in the air great enough to endanger those exposed.

Systematic construction of spin liquids on the square lattice from tensor networks with SU(2) symmetry

NASA Astrophysics Data System (ADS)

Mambrini, Matthieu; Orús, Román; Poilblanc, Didier

2016-11-01

We elaborate a simple classification scheme of all rank-5 SU(2) spin rotational symmetric tensors according to (i) the onsite physical spin S , (ii) the local Hilbert space V⊗4 of the four virtual (composite) spins attached to each site, and (iii) the irreducible representations of the C4 v point group of the square lattice. We apply our scheme to draw a complete list of all SU(2)-symmetric translationally and rotationally invariant projected entangled pair states (PEPS) with bond dimension D ≤6 . All known SU(2)-symmetric PEPS on the square lattice are recovered and simple generalizations are provided in some cases. More generally, to each of our symmetry class can be associated a (D -1 )-dimensional manifold of spin liquids (potentially) preserving lattice symmetries and defined in terms of D -independent tensors of a given bond dimension D . In addition, generic (low-dimensional) families of PEPS explicitly breaking either (i) particular point-group lattice symmetries (lattice nematics) or (ii) time-reversal symmetry (chiral spin liquids) or (iii) SU(2) spin rotation symmetry down to U(1 ) (spin nematics or Néel antiferromagnets) can also be constructed. We apply this framework to search for new topological chiral spin liquids characterized by well-defined chiral edge modes, as revealed by their entanglement spectrum. In particular, we show how the symmetrization of a double-layer PEPS leads to a chiral topological state with a gapless edge described by a SU (2) 2 Wess-Zumino-Witten model.

Chiral perturbation theory versus vector meson dominance in the decays ø -> ργγ and ø -> ωγγ

NASA Astrophysics Data System (ADS)

Ko, Pyungwon; Lee, Jungil; Song, H. S.

1996-02-01

It is pointed out that the radiative decays of a φ meson, φ → ϱγγ and φ → ωγγ, receive dominant contributions from the pseudoscalar ( P = η, η‧) exchanges. Using the vector meson dominance model, we find that B( φ → ϱγγ) ≈ 1.3 × 10 -4 and B( φ → ωγγ) ≈ 1.5 × 10 -5, which are mainly from the η‧ pole. Thus, these decays are well within the reach of the φ factory. Our estimates are a few orders of magnitude larger than the chiral loop contributions in the heavy vector meson chiral lagrangian, which is about (a few) ×10 -9.

Universal dissymmetry and the origin of biomolecular chirality.

PubMed

Mason, S F

1987-01-01

Handed systems are distributed over four general domains. These span the fundamental particles, the molecular enantiomers, the crystal enantiomorphs, and the spiral galaxies. The characterisation of the molecular enantiomers followed from the identification of the crystal enantiomorphs and revealed a chiral homogeneity in the biomolecules of the organic world. The origin of the homogeneity has been variously ascribed to a universal dissymmetric force, from Pasteur, or to a chance choice of the initial enantiomer perpetuated by the stereoselection of diastereomer production with recycling, from Fischer's "key and lock" hypothesis. The classical chiral fields identified by Curie require a particular time or location on the Earth's surface for a determinate molecular enantioselection, as do the weak charged current agencies of the non-classical weak interaction. The weak neutral current of the electroweak interaction provides a constant and uniform chiral agency which favours both the L-series of amino acids and polypeptides and the parent aldotriose of the D-series of sugars. The enantiomeric bias of the electroweak interaction is small at the molecular level: it may become significant either as a trigger-perturbation guiding the transition from a metastable autocatalytic racemic process to one of the two constituent enantiomeric reaction channels, or by cumulative amplification in a large chirally-homogeneous aggregate of enantiomer units.

Angular momentum content of the rho meson in lattice QCD.

PubMed

Glozman, Leonid Ya; Lang, C B; Limmer, Markus

2009-09-18

The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark component of a meson in the infrared, where mass is generated. Using a unitary transformation from the chiral basis to the ;{2S+1}L_{J} basis one may extract a partial wave content of a meson. We present results for the ground state of the rho meson using quenched simulations as well as simulations with n_{f} = 2 dynamical quarks, all for lattice spacings close to 0.15 fm. We point out that these results indicate a simple ;{3}S_{1}-wave composition of the rho meson in the infrared, like in the SU(6) flavor-spin quark model.

Kaon quark distribution functions in the chiral constituent quark model

NASA Astrophysics Data System (ADS)

Watanabe, Akira; Sawada, Takahiro; Kao, Chung Wen

2018-04-01

We investigate the valence u and s ¯ quark distribution functions of the K+ meson, vK (u )(x ,Q2) and vK (s ¯)(x ,Q2), in the framework of the chiral constituent quark model. We judiciously choose the bare distributions at the initial scale to generate the dressed distributions at the higher scale, considering the meson cloud effects and the QCD evolution, which agree with the phenomenologically satisfactory valence quark distribution of the pion and the experimental data of the ratio vK (u )(x ,Q2)/vπ (u )(x ,Q2) . We show how the meson cloud effects affect the bare distribution functions in detail. We find that a smaller S U (3 ) flavor symmetry breaking effect is observed, compared with results of the preceding studies based on other approaches.

Chiral magnetic microspheres purified by centrifugal field flow fractionation and microspheres magnetic chiral chromatography for benzoin racemate separation

PubMed Central

Tian, Ailin; Qi, Jing; Liu, Yating; Wang, Fengkang; Ito, Yoichiro; Wei, Yun

2013-01-01

Separation of enantiomers still remains a challenge due to their identical physical and chemical properties in a chiral environment, and the research on specific chiral selector along with separation techniques continues to be conducted to resolve individual enantiomers. In our laboratory the promising magnetic chiral microspheres Fe3O4@SiO2@cellulose-2, 3-bis (3, 5-dimethylphenylcarbamate) have been developed to facilitate the resolution using both its magnetic property and chiral recognition ability. In our present studies this magnetic chiral selector was first purified by centrifuge field flow fractionation, and then used to separate benzoin racemate by a chromatographic method. Uniform-sized and masking-impurity-removed magnetic chiral selector was first obtained by field flow fractionation with ethanol through a spiral column mounted on the type-J planetary centrifuge, and using the purified magnetic chiral selector, the final chromatographic separation of benzoin racemate was successfully performed by eluting with ethanol through a coiled tube (wound around the cylindrical magnet to retain the magnetic chiral selector as a stationary phase) submerged in dry ice. In addition, an external magnetic field facilitates the recycling of the magnetic chiral selector. PMID:23891368

Chiral magnetic microspheres purified by centrifugal field flow fractionation and microspheres magnetic chiral chromatography for benzoin racemate separation.

PubMed

Tian, Ailin; Qi, Jing; Liu, Yating; Wang, Fengkang; Ito, Yoichiro; Wei, Yun

2013-08-30

Separation of enantiomers still remains a challenge due to their identical physical and chemical properties in a chiral environment, and the research on specific chiral selector along with separation techniques continues to be conducted to resolve individual enantiomers. In our laboratory the promising magnetic chiral microspheres Fe3O4@SiO2@cellulose-2, 3-bis (3,5-dimethylphenylcarbamate) have been developed to facilitate the resolution using both its magnetic property and chiral recognition ability. In our present studies this magnetic chiral selector was first purified by centrifuge field flow fractionation, and then used to separate benzoin racemate by a chromatographic method. Uniform-sized and masking-impurity-removed magnetic chiral selector was first obtained by field flow fractionation with ethanol through a spiral column mounted on the type-J planetary centrifuge, and using the purified magnetic chiral selector, the final chromatographic separation of benzoin racemate was successfully performed by eluting with ethanol through a coiled tube (wound around the cylindrical magnet to retain the magnetic chiral selector as a stationary phase) submerged in dry ice. In addition, an external magnetic field facilitates the recycling of the magnetic chiral selector. Copyright © 2013 Elsevier B.V. All rights reserved.

Chiral Separations

NASA Astrophysics Data System (ADS)

Stalcup, A. M.

2010-07-01

The main goal of this review is to provide a brief overview of chiral separations to researchers who are versed in the area of analytical separations but unfamiliar with chiral separations. To researchers who are not familiar with this area, there is currently a bewildering array of commercially available chiral columns, chiral derivatizing reagents, and chiral selectors for approaches that span the range of analytical separation platforms (e.g., high-performance liquid chromatography, gas chromatography, supercritical-fluid chromatography, and capillary electrophoresis). This review begins with a brief discussion of chirality before examining the general strategies and commonalities among all of the chiral separation techniques. Rather than exhaustively listing all the chiral selectors and applications, this review highlights significant issues and differences between chiral and achiral separations, providing salient examples from specific classes of chiral selectors where appropriate.

Meat flavor precursors and factors influencing flavor precursors--A systematic review.

PubMed

Khan, Muhammad Issa; Jo, Cheorun; Tariq, Muhammad Rizwan

2015-12-01

Flavor is the sensory impression sensed by taste and smell buds and is a leading factor determining the meat quality and purchasing decision of the consumer. Meat flavor is characteristic of volatiles produced as a result of reactions of non-volatile components that are induced thermally. The water soluble compounds having low molecular weight and meat lipids are important precursors of cooked meat flavor. The Maillard reaction, lipid oxidation, and vitamin degradation are leading reactions during cooking which develop meat flavor from uncooked meat with little aroma and bloody taste. The pre-slaughter and postmortem factors like animal breed, sex, age, feed, aging and cooking conditions contribute to flavor development of cooked meat. The objective of this review is to highlight the flavor chemistry, meat flavor precursors and factors affecting meat flavor precursors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spin chirality and polarised neutron scattering

NASA Astrophysics Data System (ADS)

Plakhty, V. P.; Maleyev, S. V.; Kulda, J.; Visser, E. D.; Wosnitza, J.; Moskvin, E. V.; Brückel, Th.; Kremer, R. K.

2001-03-01

Possibilities of polarised neutrons in studies of chiral criticality are discussed. The critical exponents β C of the average chirality below TN, as well as φ C=β C+γ C and, therefore, γ C of the chiral susceptibility above TN are determined for a XY triangular lattice antiferromagnet (TLA) CsMnBr3: β C=0.44(2) , γ C=0.84(7) . The critical behaviour of the chirality that orders at TN with a relative precision of 5×10 -4 proves that the phase transition belongs to a new chiral universality class. For the TLA CsNiCl 3 ( S=1) we found in the XY region ( B=3 T) φ C=1.24(7) in agreement with the Monte-Carlo value φ C=1.22(6) for the chiral universality class. In the easy-axis region at B=1 T, φ C=0.54(4) , and the Haldane excitations are observed in the polarisation-dependent inelastic cross section above TN. The helimagnet holmium exhibits a different chiral criticality with φ C=1.56(5) , essentially higher than for TLAs.

HPLC of fluoroquinolone antibacterials using chiral stationary phase based on enantiomeric (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6.

PubMed

Choi, Hee Jung; Cho, Hwan Sun; Han, Sang Cheol; Hyun, Myung Ho

2009-02-01

A residual silanol group-protecting chiral stationary phase (CSP) based on optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 was successfully applied to the resolution of fluoroquinolone compounds including gemifloxacin mesylate. The chiral recognition ability of the residual silanol group-protecting CSP was generally greater than that of the residual silanol group-containing CSP. From these results, it was concluded that the simple protection of the residual silanol groups of the latter CSP with lipophilic n-octyl groups can improve its chiral recognition ability for the resolution of racemic fluoroquinolone compounds. The chromatographic resolution behaviors were investigated as a function of the content and type of organic and acidic modifiers and the ammonium acetate concentration in aqueous mobile phase and the column temperature. Especially, the addition of ammonium acetate to the mobile phase was found to be a quite effective means of reducing the enantiomer retentions without sacrificing the chiral recognition efficiency of the CSP.

Homochiral 3D Metal-Organic Frameworks from Chiral 1D Rods: 6 – Way Helical Packing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Sung M.; Moon, Dohyun; Jeong, Kyung S.

2011-07-20

The chiral 3D MOFs resulted from the packing of chiral 1D SBBs were studied. It was demonstrated that the final packing pattern is dependent on the dimension of SBB's. In addition, we were able to identify a new plywood-like network from ligand 2H2 exhibiting an unprecedented six-way chiral helical packing motif, which can be added on the list of invariant rod packings.

Flavor physics without flavor symmetries

NASA Astrophysics Data System (ADS)

Buchmuller, Wilfried; Patel, Ketan M.

2018-04-01

We quantitatively analyze a quark-lepton flavor model derived from a six-dimensional supersymmetric theory with S O (10 )×U (1 ) gauge symmetry, compactified on an orbifold with magnetic flux. Two bulk 16 -plets charged under the U (1 ) provide the three quark-lepton generations whereas two uncharged 10 -plets yield two Higgs doublets. At the orbifold fixed points mass matrices are generated with rank one or two. Moreover, the zero modes mix with heavy vectorlike split multiplets. The model possesses no flavor symmetries. Nevertheless, there exist a number of relations between Yukawa couplings, remnants of the underlying grand unified theory symmetry and the wave function profiles of the zero modes, which lead to a prediction of the light neutrino mass scale, mν 1˜10-3 eV and heavy Majorana neutrino masses in the range from 1 012 to 1 014 GeV . The model successfully includes thermal leptogenesis.

QCD Coupling from a Nonperturbative Determination of the Three-Flavor Λ Parameter.

PubMed

Bruno, Mattia; Brida, Mattia Dalla; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Schaefer, Stefan; Simma, Hubert; Sint, Stefan; Sommer, Rainer

2017-09-08

We present a lattice determination of the Λ parameter in three-flavor QCD and the strong coupling at the Z pole mass. Computing the nonperturbative running of the coupling in the range from 0.2 to 70 GeV, and using experimental input values for the masses and decay constants of the pion and the kaon, we obtain Λ_{MS[over ¯]}^{(3)}=341(12)  MeV. The nonperturbative running up to very high energies guarantees that systematic effects associated with perturbation theory are well under control. Using the four-loop prediction for Λ_{MS[over ¯]}^{(5)}/Λ_{MS[over ¯]}^{(3)} yields α_{MS[over ¯]}^{(5)}(m_{Z})=0.11852(84).

The effect of homogenization pressure on the flavor and flavor stability of whole milk powder.

PubMed

Park, Curtis W; Drake, MaryAnne

2017-07-01

Flavor is one of the key factors that can limit the application and shelf life of dried dairy ingredients. Many off-flavors are caused during ingredient manufacture that carry through into ingredient applications and decrease consumer acceptance. The objective of this research was to investigate the effect of homogenization pressure on the flavor and flavor stability of whole milk powder (WMP). Whole milk powder was produced from standardized pasteurized whole milk that was evaporated to 50% solids (wt/wt), homogenized in 2 stages with varying pressures (0/0, 5.5/1.4, 11.0/2.8, or 16.5/4.3 MPa), and spray dried. Whole milk powder was evaluated at 0, 3, and 6 mo of storage at 21°C. Sensory properties were evaluated by descriptive analysis. Volatile compounds were analyzed by sorptive stir bar extraction with gas chromatography-mass spectrometry. Fat globule size in condensed whole milk and particle size of powders were measured by laser diffraction. Surface free fat, inner free fat, and encapsulated fat of WMP were measured by solvent extractions. Phospholipid content was measured by ultra-high-performance liquid chromatography-evaporative light scattering. Furosine in WMP was analyzed by ultra-high-performance liquid chromatography-mass spectrometry. Increased homogenization pressure decreased cardboard and painty flavors, volatile lipid oxidation compound concentrations, fat globule size in condensed milk, surface free fat, and inner free fat in WMP. Encapsulated fat increased and phospholipid-to-encapsulated fat ratio decreased with higher homogenization pressure. Surface free fat in powders increased cardboard flavor and lipid oxidation. These results indicate that off-flavors were decreased with increased homogenization pressures in WMP due to the decrease in free fat. To decrease off-flavor intensities in WMP, manufacturers should carefully evaluate these parameters during ingredient manufacture. Copyright © 2017 American Dairy Science Association. Published

Green synthesis of a typical chiral stationary phase of cellulose-tris(3, 5-dimethylphenylcarbamate)

PubMed Central

2013-01-01

Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far. Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization. Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl. PMID:23890199

Effects of the regularization on the restoration of chiral and axial symmetries

NASA Astrophysics Data System (ADS)

Costa, P.; Ruivo, M. C.; de Sousa, C. A.

2008-05-01

The effects of a type of regularization for finite temperatures on the restoration of chiral and axial symmetries are investigated within the SU(3) Nambu-Jona-Lasinio model. The regularization consists in using an infinite cutoff in the integrals that are convergent at finite temperature, a procedure that allows one to take into account the effects of high momentum quarks at high temperatures. It is found that the critical temperature for the phase transition is closer to lattice results than the one obtained with the conventional regularization, and the restoration of chiral and axial symmetries, signaled by the behavior of several observables, occurs simultaneously and at a higher temperature. The restoration of the axial symmetry appears as a natural consequence of the full recovering of the chiral symmetry that was dynamically broken. By using an additional ansatz that simulates instanton suppression effects, by means of a convenient temperature dependence of the anomaly coefficient, we found that the restoration of U(2) symmetry is shifted to lower values, but the dominant effect at high temperatures comes from the new regularization that enhances the decrease of quark condensates, especially in the strange sector.

Wilson loops and chiral correlators on squashed spheres

NASA Astrophysics Data System (ADS)

Fucito, F.; Morales, J. F.; Poghossian, R.

2015-11-01

We study chiral deformations of N=2 and N=4 supersymmetric gauge theories obtained by turning on τ J tr Φ J interactions with Φ the N=2 superfield. Using localization, we compute the deformed gauge theory partition function Z(overrightarrow{τ}|q) and the expectation value of circular Wilson loops W on a squashed four-sphere. In the case of the deformed {N}=4 theory, exact formulas for Z and W are derived in terms of an underlying U( N) interacting matrix model replacing the free Gaussian model describing the {N}=4 theory. Using the AGT correspondence, the τ J -deformations are related to the insertions of commuting integrals of motion in the four-point CFT correlator and chiral correlators are expressed as τ-derivatives of the gauge theory partition function on a finite Ω-background. In the so called Nekrasov-Shatashvili limit, the entire ring of chiral relations is extracted from the ɛ-deformed Seiberg-Witten curve. As a byproduct of our analysis we show that SU(2) gauge theories on rational Ω-backgrounds are dual to CFT minimal models.

Collective three-flavor oscillations of supernova neutrinos

NASA Astrophysics Data System (ADS)

Dasgupta, Basudeb; Dighe, Amol

2008-06-01

Neutrinos and antineutrinos emitted from a core collapse supernova interact among themselves, giving rise to collective flavor conversion effects that are significant near the neutrinosphere. We develop a formalism to analyze these collective effects in the complete three-flavor framework. It naturally generalizes the spin-precession analogy to three flavors and is capable of analytically describing phenomena like vacuum/Mikheyev-Smirnov-Wolfenstein (MSW) oscillations, synchronized oscillations, bipolar oscillations, and spectral split. Using the formalism, we demonstrate that the flavor conversions may be “factorized” into two-flavor oscillations with hierarchical frequencies. We explicitly show how the three-flavor solution may be constructed by combining two-flavor solutions. For a typical supernova density profile, we identify an approximate separation of regions where distinctly different flavor conversion mechanisms operate, and demonstrate the interplay between collective and MSW effects. We pictorialize our results in terms of the “e3-e8 triangle” diagram, which is a tool that can be used to visualize three-neutrino flavor conversions in general, and offers insights into the analysis of the collective effects in particular.

Synthesis of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) in an ionic liquid and its chiral separation efficiency as stationary phase.

PubMed

Liu, Runqiang; Zhang, Yijun; Bai, Lianyang; Huang, Mingxian; Chen, Jun; Zhang, Yuping

2014-04-11

A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) (CBDMPC) was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl). The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP) was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC) and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media.

Synthesis of Cellulose-2,3-bis(3,5-dimethylphenylcarbamate) in an Ionic Liquid and Its Chiral Separation Efficiency as Stationary Phase

PubMed Central

Liu, Runqiang; Zhang, Yijun; Bai, Lianyang; Huang, Mingxian; Chen, Jun; Zhang, Yuping

2014-01-01

A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) (CBDMPC) was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl). The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP) was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC) and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media. PMID:24733066

Flavoring exposure in food manufacturing.

PubMed

Curwin, Brian D; Deddens, Jim A; McKernan, Lauralynn T

2015-05-01

Flavorings are substances that alter or enhance the taste of food. Workers in the food-manufacturing industry, where flavorings are added to many products, may be exposed to any number of flavoring compounds. Although thousands of flavoring substances are in use, little is known about most of these in terms of worker health effects, and few have occupational exposure guidelines. Exposure assessment surveys were conducted at nine food production facilities and one flavor manufacturer where a total of 105 area and 74 personal samples were collected for 13 flavoring compounds including five ketones, five aldehydes, and three acids. The majority of the samples were below the limit of detection (LOD) for most compounds. Diacetyl had eight area and four personal samples above the LOD, whereas 2,3-pentanedione had three area samples above the LOD. The detectable values ranged from 25-3124 ppb and 15-172 ppb for diacetyl and 2,3-pentanedione respectively. These values exceed the proposed National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for these compounds. The aldehydes had the most detectable samples, with each of them having >50% of the samples above the LOD. Acetaldehyde had all but two samples above the LOD, however, these samples were below the OSHA PEL. It appears that in the food-manufacturing facilities surveyed here, exposure to the ketones occurs infrequently, however levels above the proposed NIOSH REL were found. Conversely, aldehyde exposure appears to be ubiquitous.

Flavoring exposure in food manufacturing

PubMed Central

Curwin, Brian D.; Deddens, Jim A.; McKernan, Lauralynn T.

2015-01-01

Flavorings are substances that alter or enhance the taste of food. Workers in the food-manufacturing industry, where flavorings are added to many products, may be exposed to any number of flavoring compounds. Although thousands of flavoring substances are in use, little is known about most of these in terms of worker health effects, and few have occupational exposure guidelines. Exposure assessment surveys were conducted at nine food production facilities and one flavor manufacturer where a total of 105 area and 74 personal samples were collected for 13 flavoring compounds including five ketones, five aldehydes, and three acids. The majority of the samples were below the limit of detection (LOD) for most compounds. Diacetyl had eight area and four personal samples above the LOD, whereas 2,3-pentanedione had three area samples above the LOD. The detectable values ranged from 25–3124 ppb and 15–172 ppb for diacetyl and 2,3-pentanedione respectively. These values exceed the proposed National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for these compounds. The aldehydes had the most detectable samples, with each of them having >50% of the samples above the LOD. Acetaldehyde had all but two samples above the LOD, however, these samples were below the OSHA PEL. It appears that in the food-manufacturing facilities surveyed here, exposure to the ketones occurs infrequently, however levels above the proposed NIOSH REL were found. Conversely, aldehyde exposure appears to be ubiquitous. PMID:25052692

Series of chiral interpenetrating 3d-4f heterometallic MOFs: Luminescent sensors and magnetic properties

NASA Astrophysics Data System (ADS)

Zhang, Xiaolei; Chen, Chen; Liu, Xiaoli; Gao, Peng; Hu, Ming

2017-09-01

Series of chiral 3d-4f heterometallic MOFs based on a multidentate terpyridyl carboxylic acid ligand have been synthesized under the solvothermal conditions, namely, [LnZnL(CO3)2(H2O)]n (Ln = Eu (1), Gd (2), Dy (3), Ho (4), Er (5), Tm (6), Yb (7), Lu (8)) (HL = 4‧-(4-carboxyphenyl)-2,2‧:6‧,2″-terpyridine). Compounds 1-8 were structurally characterized by the elemental analyses, infrared spectra, and single crystal X-ray diffractions. Compounds 1-8 exhibit the chiral interpenetrating 3D frameworks. Interestingly, 1 can serve as the luminescent sensor to detect nitrobenzene molecules with high sensitivity. The investigations on CD spectra of single crystals clearly assigned the Cotton effect, indicating that there exist two chiral enantiomers of 1-8 in the course of crystallization. The magnetic properties of 2 and 7 were exploited, respectively.

Chiral symmetry constraints on resonant amplitudes

NASA Astrophysics Data System (ADS)

Bruns, Peter C.; Mai, Maxim

2018-03-01

We discuss the impact of chiral symmetry constraints on the quark-mass dependence of meson resonance pole positions, which are encoded in non-perturbative parametrizations of meson scattering amplitudes. Model-independent conditions on such parametrizations are derived, which are shown to guarantee the correct functional form of the leading quark-mass corrections to the resonance pole positions. Some model amplitudes for ππ scattering, widely used for the determination of ρ and σ resonance properties from results of lattice simulations, are tested explicitly with respect to these conditions.

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents.

PubMed

Zaccone, Eric J; Goldsmith, W Travis; Shimko, Michael J; Wells, J R; Schwegler-Berry, Diane; Willard, Patsy A; Case, Shannon L; Thompson, Janet A; Fedan, Jeffrey S

2015-12-15

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance,we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity.We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (Rt) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na+ transport,without affecting Cl- transport or Na+,K+-pump activity. Rt was unaffected. Na+ transport recovered 18 h after exposure. Concentrations (100-360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro.

N = 2 S-duality revisited

NASA Astrophysics Data System (ADS)

Buican, Matthew; Laczko, Zoltan; Nishinaka, Takahiro

2017-09-01

Using the chiral algebra bootstrap, we revisit the simplest Argyres-Douglas (AD) generalization of Argyres-Seiberg S-duality. We argue that the exotic AD superconformal field theory (SCFT), T_{3,3/2} , emerging in this duality splits into a free piece and an interacting piece, T_X , even though this factorization seems invisible in the Seiberg-Witten (SW) curve derived from the corresponding M5-brane construction. Without a Lagrangian, an associated topological field theory, a BPS spectrum, or even an SW curve, we nonetheless obtain exact information about T_X by bootstrapping its chiral algebra, {}_X(T_X) , and finding the corresponding vacuum character in terms of Affine Kac-Moody characters. By a standard 4D/2D correspondence, this result gives us the Schur index for T_X and, by studying this quantity in the limit of small S 1, we make contact with a proposed S 1 reduction. Along the way, we discuss various properties of T_X : as an N = 1 theory, it has flavor symmetry SU(3) × SU(2) × U(1), the central charge of {}_X(T_X) matches the central charge of the bc ghosts in bosonic string theory, and its global SU(2) symmetry has a Witten anomaly. This anomaly does not prevent us from building conformal manifolds out of arbitrary numbers of T_X theories (giving us a surprisingly close AD relative of Gaiotto's T N theories), but it does lead to some open questions in the context of the chiral algebra/4D N =2SCFT correspondence.

Chirality Differentiation by Diffusion in Chiral Nematic Liquid Crystals

NASA Astrophysics Data System (ADS)

Jiang, Jinghua; Yang, Deng-Ke

2017-01-01

Chirality is of great importance in the living world. It helps differentiate biochemical reactions such as those that take place during digestion. It may also help differentiate physical processes such as diffusion. Aiming to study the latter effect, we investigate the diffusion of guest chiral molecules in chiral nematic (cholesteric) liquid-crystal hosts. We discover that the diffusion dramatically depends on the handedness of the guest and host molecules and the chiral differentiation is greatly enhanced by the proper alignment of the liquid-crystal host. The diffusion of a guest chiral molecule in a chiral host with the same handedness is much faster than in a chiral host with opposite handedness. We also observe that the differentiation of chirality depends on the diffusion direction with respect to the twisting direction (helical axis). These results might be important in understanding effects of chirality on physical processes that take place in biological organisms. In addition, this effect could be utilized for enantiomer separation.

Chiral signs of TPPS co-assemblies with chiral gelators: role of molecular and supramolecular chirality.

PubMed

Wang, Qiuling; Zhang, Li; Yang, Dong; Li, Tiesheng; Liu, Minghua

2016-10-13

A dianionic tetrakis(4-sulfonatophenyl)porphyrin (TPPS) self-assembled into J-aggregates when it co-assembled with a chiral cationic amphiphile via supramolecular gelation. The chiral signs of TPPS J aggregates followed the supramolecular chirality of amphiphilic assemblies rather than the molecular chirality of the amphiphile.

Parity partners in the baryon resonance spectrum

DOE PAGES

Lu, Ya; Chen, Chen; Roberts, Craig D.; ...

2017-07-28

Here, we describe a calculation of the spectrum of flavor-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector x vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavor-antitriplet scalar, pseudoscalar, vector, and flavor-sextet axial-vector quark-quark correlations can all play active roles. The model yields reasonable masses for all systems studied and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of theirmore » internal structure: ground-state, even-parity baryons are constituted, almost exclusively, from like-parity diquark correlations, but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.« less

Parity partners in the baryon resonance spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Ya; Chen, Chen; Roberts, Craig D.

Here, we describe a calculation of the spectrum of flavor-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector x vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavor-antitriplet scalar, pseudoscalar, vector, and flavor-sextet axial-vector quark-quark correlations can all play active roles. The model yields reasonable masses for all systems studied and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of theirmore » internal structure: ground-state, even-parity baryons are constituted, almost exclusively, from like-parity diquark correlations, but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.« less

Enantiopure pseudo-C3-symmetric titanium alkoxide with propeller-like chirality.

PubMed

Axe, Philip; Bull, Steven D; Davidson, Matthew G; Gilfillan, Carly J; Jones, Matthew D; Robinson, Diane E J E; Turner, Luke E; Mitchell, William L

2007-01-18

An enantiopure amine tris(phenolate) ligand containing a single stereogenic center has been used to control the propeller-like chirality of a derived pseudo-C3-symmetric titanium isopropoxide complex with excellent levels of diastereocontrol. [structure: see text].

Role of protein-glutathione contacts in defining glutaredoxin-3 [2Fe-2S] cluster chirality, ligand exchange and transfer chemistry.

PubMed

Sen, Sambuddha; Cowan, J A

2017-10-01

Monothiol glutaredoxins (Grx) serve as intermediate cluster carriers in iron-sulfur cluster trafficking. The [2Fe-2S]-bound holo forms of Grx proteins display cysteinyl coordination from exogenous glutathione (GSH), in addition to contact from protein-derived Cys. Herein, we report mechanistic studies that investigate the role of exogenous glutathione in defining cluster chirality, ligand exchange, and the cluster transfer chemistry of Saccharomyces cerevisiae Grx3. Systematic perturbations were introduced to the glutathione-binding site by substitution of conserved charged amino acids that form crucial electrostatic contacts with the glutathione molecule. Native Grx3 could also be reconstituted in the absence of glutathione, with either DTT, BME or free L-cysteine as the source of the exogenous Fe-S ligand contact, while retaining full functional reactivity. The delivery of the [2Fe-2S] cluster to Grx3 from cluster donor proteins such as Isa, Nfu, and a [2Fe-2S](GS) 4 complex, revealed that electrostatic contacts are of key importance for positioning the exogenous glutathione that in turn influences the chiral environment of the cluster. All Grx3 derivatives were reconstituted by standard chemical reconstitution protocols and found to transfer cluster to apo ferredoxin 1 (Fdx1) at rates comparable to native protein, even when using DTT, BME or free L-cysteine as a thiol source in place of GSH during reconstitution. Kinetic analysis of cluster transfer from holo derivatives to apo Fdx1 has led to a mechanistic model for cluster transfer chemistry of native holo Grx3, and identification of the likely rate-limiting step for the reaction.

Maltodextrins as chiral selectors in CE: molecular structure effect of basic chiral compounds on the enantioseparation.

PubMed

Tabani, Hadi; Fakhari, Ali Reza; Nojavan, Saeed

2014-10-01

Prediction of chiral separation for a compound using a chiral selector is an interesting and debatable work. For this purpose, in this study 23 chiral basic drugs with different chemical structures were selected as model solutes and the influence of their chemical structures on the enantioseparation in the presence of maltodextrin (MD) as chiral selector was investigated. For chiral separation, a 100-mM phosphate buffer solution (pH 3.0) containing 10% (w/v) MD with dextrose equivalent (DE) of 4-7 as chiral selector at the temperature of 25°C and voltage of 20 kV was used. Under this condition, baseline separation was achieved for nine chiral compounds and partial separation was obtained for another six chiral compounds while no enantioseparation was obtained for the remaining eight compounds. The results showed that the existence of at least two aromatic rings or cycloalkanes and an oxygen or nitrogen atom or -CN group directly bonded to the chiral center are necessary for baseline separation. With the obtained results in this study, chiral separation of a chiral compound can be estimated with MD-modified capillary electrophoresis before analysis. This prediction will minimize the number of preliminary experiments required to resolve enantiomers and will save time and cost. © 2014 Wiley Periodicals, Inc.

Covariant and 3 + 1 Equations for Dynamo-Chiral General Relativistic Magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Del Zanna, L.; Bucciantini, N.

2018-06-01

The exponential amplification of initial seed magnetic fields in relativistic plasmas is a very important topic in astrophysics, from the conditions in the early Universe to the interior of neutron stars. While dynamo action in a turbulent plasma is often invoked, in the last years a novel mechanism of quantum origin has gained increasingly more attention, namely the Chiral Magnetic Effect (CME). This has been recognized in semi-metals and it is most likely at work in the quark-gluon plasma formed in heavy-ion collision experiments, where the highest magnetic fields in nature, up to B ˜ 1018 G, are produced. This effect is expected to survive even at large hydrodynamical/MHD scales and it is based on the chiral anomaly due to an imbalance between left- and right-handed relativistic fermions in the constituent plasma. Such imbalance leads to an electric current parallel to an external magnetic field, which is precisely the same mechanism of an α-dynamo action in classical MHD. Here we extend the close parallelism between the chiral and the dynamo effects to relativistic plasmas and we propose a unified, fully covariant formulation of the generalized Ohm's law. Moreover, we derive for the first time the 3 + 1 general relativistic MHD equations for a chiral plasma both in flat and curved spacetimes, in view of numerical investigation of the CME in compact objects, especially magnetars, or of the interplay among the non-ideal magnetic effects of dynamo, the CME and reconnection.

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaccone, Eric J.; Goldsmith, W. Travis; Shimko, Michael J.

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance, we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity. We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl ormore » 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (R{sub t}) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na{sup +} transport, without affecting Cl{sup −} transport or Na{sup +},K{sup +}-pump activity. R{sub t} was unaffected. Na{sup +} transport recovered 18 h after exposure. Concentrations (100–360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro. - Highlights: • Butter flavoring vapor effects on human cultured airway epithelium were studied. • Na transport was reduced by a 6-h exposure to 25 ppm diacetyl and 2,3-pentanedione. • Na transport recovered 18 h after exposure. • > 60 ppm transepithelial voltage and resistance were abolished; cells were damaged. • Cells metabolized diacetyl and 2,3-pentanedione

21 CFR 172.585 - Sugar beet extract flavor base.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sugar beet extract flavor base. 172.585 Section... HUMAN CONSUMPTION Flavoring Agents and Related Substances § 172.585 Sugar beet extract flavor base. Sugar beet extract flavor base may be safely used in food in accordance with the provisions of this...

21 CFR 172.585 - Sugar beet extract flavor base.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sugar beet extract flavor base. 172.585 Section... HUMAN CONSUMPTION Flavoring Agents and Related Substances § 172.585 Sugar beet extract flavor base. Sugar beet extract flavor base may be safely used in food in accordance with the provisions of this...

21 CFR 172.585 - Sugar beet extract flavor base.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sugar beet extract flavor base. 172.585 Section... HUMAN CONSUMPTION Flavoring Agents and Related Substances § 172.585 Sugar beet extract flavor base. Sugar beet extract flavor base may be safely used in food in accordance with the provisions of this...

21 CFR 172.585 - Sugar beet extract flavor base.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sugar beet extract flavor base. 172.585 Section 172... CONSUMPTION Flavoring Agents and Related Substances § 172.585 Sugar beet extract flavor base. Sugar beet...) Sugar beet extract flavor base is the concentrated residue of soluble sugar beet extractives from which...

Gold(I)-Catalysed Hydroarylation of 1,3-Disubstituted Allenes with Efficient Axial-to-Point Chirality Transfer.

PubMed

Sutherland, Daniel R; Kinsman, Luke; Angiolini, Stuart M; Rosair, Georgina M; Lee, Ai-Lan

2018-05-11

Hydroarylation of enantioenriched 1,3-disubstituted allenes has the potential to proceed with axial-to-point chirality transfer to yield enantioenriched allylated (hetero)aryl compounds. However, the gold-catalysed intermolecular reaction was previously reported to occur with no chirality transfer owing to competing allene racemisation. Herein, we describe the development of the first intermolecular hydroarylations of allenes to proceed with efficient chirality transfer and summarise some of the key criteria for achieving high regio- and stereoselectivity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prenatal flavor exposure affects flavor recognition and stress-related behavior of piglets.

PubMed

Oostindjer, Marije; Bolhuis, J Elizabeth; van den Brand, Henry; Kemp, Bas

2009-11-01

Exposure to flavors in the amniotic fluid and mother's milk derived from the maternal diet has been shown to modulate food preferences and neophobia of young animals of several species. Aim of the experiment was to study the effects of pre- and postnatal flavor exposure on behavior of piglets during (re)exposure to this flavor. Furthermore, we investigated whether varying stress levels, caused by different test settings, affected behavior of animals during (re)exposure. Piglets were exposed to anisic flavor through the maternal diet during late gestation and/or during lactation or never. Piglets that were prenatally exposed to the flavor through the maternal diet behaved differently compared with unexposed pigs during reexposure to the flavor in several tests, suggesting recognition of the flavor. The differences between groups were more pronounced in tests with relatively high stress levels. This suggests that stress levels, caused by the design of the test, can affect the behavior shown in the presence of the flavor. We conclude that prenatal flavor exposure affects behaviors of piglets that are indicative of recognition and that these behaviors are influenced by stress levels during (re)exposure.

Chiral Domain Structure in Superfluid 3He-A Studied by Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Kasai, J.; Okamoto, Y.; Nishioka, K.; Takagi, T.; Sasaki, Y.

2018-05-01

The existence of a spatially varying texture in superfluid 3He is a direct manifestation of the complex macroscopic wave function. The real space shape of the texture, namely, a macroscopic wave function, has been studied extensively with the help of theoretical modeling but has never been directly observed experimentally with spatial resolution. We have succeeded in visualizing the texture by a specialized magnetic resonance imaging. With this new technology, we have discovered that the macroscopic chiral domains, of which sizes are as large as 1 mm, and corresponding chiral domain walls exist rather stably in 3He - A film at temperatures far below the transition temperature.

Determination of the QCD Λ Parameter and the Accuracy of Perturbation Theory at High Energies.

PubMed

Dalla Brida, Mattia; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer

2016-10-28

We discuss the determination of the strong coupling α_{MS[over ¯]}(m_{Z}) or, equivalently, the QCD Λ parameter. Its determination requires the use of perturbation theory in α_{s}(μ) in some scheme s and at some energy scale μ. The higher the scale μ, the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the Λ parameter in three-flavor QCD, we perform lattice computations in a scheme that allows us to nonperturbatively reach very high energies, corresponding to α_{s}=0.1 and below. We find that (continuum) perturbation theory is very accurate there, yielding a 3% error in the Λ parameter, while data around α_{s}≈0.2 are clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.

Light-directing chiral liquid crystal nanostructures: from 1D to 3D.

PubMed

Bisoyi, Hari Krishna; Li, Quan

2014-10-21

Endowing external, remote, and dynamic control to self-organized superstructures with desired functionalities is a principal driving force in the bottom-up nanofabrication of molecular devices. Light-driven chiral molecular switches or motors in liquid crystal (LC) media capable of self-organizing into optically tunable one-dimensional (1D) and three-dimensional (3D) superstructures represent such an elegant system. As a consequence, photoresponsive cholesteric LCs (CLCs), i.e., self-organized 1D helical superstructures, and LC blue phases (BPs), i.e., self-organized 3D periodic cubic lattices, are emerging as a new generation of multifunctional supramolecular 1D and 3D photonic materials in their own right because of their fundamental academic interest and technological significance. These smart stimuli-responsive materials can be facilely fabricated from achiral LC hosts by the addition of a small amount of a light-driven chiral molecular switch or motor. The photoresponsiveness of these materials is a result of both molecular interaction and geometry changes in the chiral molecular switch upon light irradiation. The doped photoresponsive CLCs undergo light-driven pitch modulation and/or helix inversion, which has many applications in color filters, polarizers, all-optical displays, optical lasers, sensors, energy-saving smart devices, and so on. Recently, we have conceptualized and rationally synthesized different light-driven chiral molecular switches that have very high helical twisting powers (HTPs) and exhibit large changes in HTP in different states, thereby enabling wide phototunability of the systems by the addition of very small amounts of the molecular switches into commercially available achiral LCs. The light-driven chiral molecular switches are based on well-recognized azobenzene, dithienylcyclopentene, and spirooxazine derivatives. We have demonstrated high-resolution and lightweight photoaddressable displays without patterned electronics on

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents

PubMed Central

Zaccone, Eric J.; Goldsmith, W. Travis; Shimko, Michael J.; Wells, J.R.; Schwegler-Berry, Diane; Willard, Patsy A.; Case, Shannon L.; Thompson, Janet A.; Fedan, Jeffrey S.

2016-01-01

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance, we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity. We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥60 ppm) and the effects on short circuit current and transepithelial resistance (Rt) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na+ transport, without affecting Cl− transport or Na+,K+-pump activity. Rt was unaffected. Na+ transport recovered 18 h after exposure. Concentrations (100–360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro. PMID:26454031

On vibrational circular dichroism chirality transfer in electron donor-acceptor complexes: a prediction for the quinine···BF3 system.

PubMed

Rode, Joanna E; Jamróz, Michał H; Dobrowolski, Jan Cz; Sadlej, Joanna

2012-08-02

Vibrational circular dichroism (VCD) chirality transfer occurs when an achiral molecule interacts with a chiral one and becomes VCD-active. Unlike for H-bonds, for organic electron donor-acceptor (EDA) complexes this phenomenon remains almost unknown. Here, the VCD chirality transfer from chiral quinine to achiral BF3 is studied at the B3LYP/aug-cc-pVDZ level. Accessibility of four quinine electron donor sites changes with conformation. Therefore, the quinine conformational landscape was explored and a considerable agreement between X-ray and the most stable conformer geometries was achieved. The BF3 complex through the aliphatic quinuclidine N atom is definitely dominating and is predicted to be easily recognizable in the VCD spectrum. Out of several VCD chirality transfer modes, the ν(s)(BF3) mode, the most intense in the entire VCD spectrum, satisfies the VCD mode robustness criterion and can be used for monitoring the chirality transfer phenomenon in quinine···BF3 system.

[Inheritance on and innovation of traditional Chinese medicine (TCM) flavor theory and TCM flavor standardization principle flavor theory in Compendium of Materia Medica].

PubMed

Zhang, Wei; Zhang, Rui-xian; Li, Jian

2015-12-01

All previous literatures about Chinese herbal medicines show distinctive traditional Chinese medicine (TCM) flavors. Compendium of Materia Medica is an influential book in TCM history. The TCM flavor theory and flavor standardization principle in this book has important significance for modern TCM flavor standardization. Compendium of Materia Medica pays attention to the flavor theory, explain the relations between the flavor of medicine and its therapeutic effects by means of Neo-Confucianism of the Song and Ming Dynasties. However,the book has not reflected and further developed the systemic theory, which originated in the Jin and Yuan dynasty. In Compendium of Materia Medica , flavor are standardized just by tasting medicines, instead of deducing flavors. Therefore, medicine tasting should be adopted as the major method to standardize the flavor of medicine.

Critical Behavior and Macroscopic Phase Diagram of the Monoaxial Chiral Helimagnet Cr 1/3NbS 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clements, Eleanor M.; Das, Raja; Li, Ling

2017-07-26

Cr 1/3NbS 2 is a unique example of a hexagonal chiral helimagnet with high crystalline anisotropy, and has generated growing interest for a possible magnetic field control of the incommensurate spin spiral. Here, we construct a comprehensive phase diagram based on detailed magnetization measurements of a high quality single crystal of Cr 1/3NbS 2 over three magnetic field regions. An analysis of the critical properties in the forced ferromagnetic region yields 3D Heisenberg exponents β = 0.3460 ± 0.040, γ = 1.344 ± 0.002, and T C = 130.78 K ± 0.044, which are consistent with the localized nature themore » of Cr 3+ moments and suggest short-range ferromagnetic interactions. We exploit the temperature and magnetic field dependence of magnetic entropy change (ΔS M) to accurately map the nonlinear crossover to the chiral soliton lattice regime from the chiral helimagnetic phase. Our observations in the low field region are consistent with the existence of chiral ordering in a temperature range above the Curie temperature, T C < T < T*, where a first-order transition has been previously predicted. An analysis of the universal behavior of ΔS M(T,H) experimentally demonstrates for the first time the first-order nature of the onset of chiral ordering.« less

21 CFR 172.585 - Sugar beet extract flavor base.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sugar beet extract flavor base. 172.585 Section... Related Substances § 172.585 Sugar beet extract flavor base. Sugar beet extract flavor base may be safely used in food in accordance with the provisions of this section. (a) Sugar beet extract flavor base is...

CLS 2+1 flavor simulations at physical light-and strange-quark masses

NASA Astrophysics Data System (ADS)

Mohler, Daniel; Schaefer, Stefan; Simeth, Jakob

2018-03-01

We report recent efforts by CLS to generate an ensemble with physical lightand strange-quark masses in a lattice volume of 192 × 963 at β = 3:55 corresponding to a lattice spacing of 0:064 fm. This ensemble is being generated as part of the CLS 2+1 flavor effort with improved Wilson fermions. Our simulations currently cover 5 lattice spacings ranging from 0:039 fm to 0:086 fm at various pion masses along chiral trajectories with either the sum of the quark masses kept fixed, or with the strange-quark mass at the physical value. The current status of simulations is briefly reviewed, including a short discussion of measured autocorrelation times and of the main features of the simulations. We then proceed to discuss the thermalization strategy employed for the generation of the physical quark-mass ensemble and present first results for some simple observables. Challenges encountered in the simulation are highlighted.

Enantioselective synthesis of chiral 3-aryl-1-indanones through rhodium-catalyzed asymmetric intramolecular 1,4-addition.

PubMed

Yu, Yue-Na; Xu, Ming-Hua

2013-03-15

Enantioselective synthesis of potentially useful chiral 3-aryl-1-indanones was achieved through a rhodium-catalyzed asymmetric intramolecular 1,4-addition of pinacolborane chalcone derivatives using extraordinary simple MonoPhos as chiral ligand under relatively mild conditions. This novel protocol offers an easy access to a wide variety of enantioenriched 3-aryl-1-indanone derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 95% ee).

Compatible orders and fermion-induced emergent symmetry in Dirac systems

NASA Astrophysics Data System (ADS)

Janssen, Lukas; Herbut, Igor F.; Scherer, Michael M.

2018-01-01

We study the quantum multicritical point in a (2+1)-dimensional Dirac system between the semimetallic phase and two ordered phases that are characterized by anticommuting mass terms with O (N1) and O (N2) symmetries, respectively. Using ɛ expansion around the upper critical space-time dimension of four, we demonstrate the existence of a stable renormalization-group fixed point, enabling a direct and continuous transition between the two ordered phases directly at the multicritical point. This point is found to be characterized by an emergent O (N1+N2) symmetry for arbitrary values of N1 and N2 and fermion flavor numbers Nf as long as the corresponding representation of the Clifford algebra exists. Small O (N ) -breaking perturbations near the chiral O (N ) fixed point are therefore irrelevant. This result can be traced back to the presence of gapless Dirac degrees of freedom at criticality, and it is in clear contrast to the purely bosonic O (N ) fixed point, which is stable only when N <3 . As a by-product, we obtain predictions for the critical behavior of the chiral O (N ) universality classes for arbitrary N and fermion flavor number Nf. Implications for critical Weyl and Dirac systems in 3+1 dimensions are also briefly discussed.

Quasinormal modes of charged magnetic black branes & chiral magnetic transport

NASA Astrophysics Data System (ADS)

Ammon, Martin; Kaminski, Matthias; Koirala, Roshan; Leiber, Julian; Wu, Jackson

2017-04-01

We compute quasinormal modes (QNMs) of the metric and gauge field perturbations about black branes electrically and magnetically charged in the Einstein-Maxwell-Chern-Simons theory. By the gauge/gravity correspondence, this theory is dual to a particular class of field theories with a chiral anomaly, in a thermal charged plasma state subjected to a constant external magnetic field, B. The QNMs are dual to the poles of the two-point functions of the energy-momentum and axial current operators, and they encode information about the dissipation and transport of charges in the plasma. Complementary to the gravity calculation, we work out the hydrodynamic description of the dual field theory in the presence of a chiral anomaly, and a constant external B. We find good agreement with the weak field hydrodynamics, which can extend beyond the weak B regime into intermediate regimes. Furthermore, we provide results that can be tested against thermodynamics and hydrodynamics in the strong B regime. We find QNMs exhibiting Landau level behavior, which become long-lived at large B if the anomaly coefficient exceeds a critical magnitude. Chiral transport is analyzed beyond the hydrodynamic approximation for the five (formerly) hydrodynamic modes, including a chiral magnetic wave.

Chiral Recognition and Separation by Chirality-Enriched Metal-Organic Frameworks.

PubMed

Das, Saikat; Xu, Shixian; Ben, Teng; Qiu, Shilun

2018-05-16

Endowed with chiral channels and pores, chiral metal-organic frameworks (MOFs) are highly useful; however, their synthesis remains a challenge given that most chiral building blocks are expensive. Although MOFs with induced chirality have been reported to avoid this shortcoming, no study providing evidence for the ee value of such MOFs has yet been reported. We herein describe the first study on the efficiency of chiral induction in MOFs using inexpensive achiral building blocks and fully recoverable chiral dopants to control the handedness of racemic MOFs. This method yielded chirality-enriched MOFs with accessible pores. The ability of the materials to form host-guest complexes was probed with enantiomers of varying size and coordination and in solvents with varying polarity. Furthermore, mixed-matrix membranes (MMMs) composed of chirality-enriched MOF particles dispersed in a polymer matrix demonstrated a new route for chiral separation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral magnetic effect without chirality source in asymmetric Weyl semimetals

NASA Astrophysics Data System (ADS)

Kharzeev, Dmitri E.; Kikuchi, Yuta; Meyer, René

2018-05-01

We describe a new type of the chiral magnetic effect (CME) that should occur in Weyl semimetals (WSMs) with an asymmetry in the dispersion relations of the left- and right-handed (LH and RH) chiral Weyl fermions. In such materials, time-dependent pumping of electrons from a non-chiral external source can generate a non-vanishing chiral chemical potential. This is due to the different capacities of the LH and RH chiral Weyl cones arising from the difference in the density of states in the LH and RH cones. The chiral chemical potential then generates, via the chiral anomaly, a current along the direction of an applied magnetic field even in the absence of an external electric field. The source of chirality imbalance in this new setup is thus due to the band structure of the system and the presence of (non-chiral) electron source, and not due to the parallel electric and magnetic fields. We illustrate the effect by an argument based on the effective field theory, and by the chiral kinetic theory calculation for a rotationally invariant WSM with different Fermi velocities in the left and right chiral Weyl cones; we also consider the case of a WSM with Weyl nodes at different energies. We argue that this effect is generically present in WSMs with different dispersion relations for LH and RH chiral Weyl cones, such as SrSi2 recently predicted as a WSM with broken inversion and mirror symmetries, as long as the chiral relaxation time is much longer than the transport scattering time.

Chiral Haldane phases of SU(N ) quantum spin chains

NASA Astrophysics Data System (ADS)

Roy, Abhishek; Quella, Thomas

2018-04-01

Gapped quantum spin chains with symmetry PSU(N ) =SU(N ) /ZN are known to possess N distinct symmetry protected topological phases. Besides the trivial phase, there are N -1 Haldane phases which are distinguished by the occurrence of massless boundary spins. We give an expression for a universal AKLT Hamiltonian for an arbitrary symmetry group, including the case where inversion symmetry is broken. Using a diagrammatic method, we construct Hamiltonians for two of the topological classes in SU(N ) that arise when the physical spin is in the adjoint representation. Since our results are valid for all N , we also discuss the large-N limit.

Optical activity of chirally distorted nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tepliakov, Nikita V.; Baimuratov, Anvar S.; Baranov, Alexander V.

2016-05-21

We develop a general theory of optical activity of semiconductor nanocrystals whose chirality is induced by a small perturbation of their otherwise achiral electronic subsystems. The optical activity is described using the quantum-mechanical expressions for the rotatory strengths and dissymmetry factors introduced by Rosenfeld. We show that the rotatory strengths of optically active transitions are decomposed on electric dipole and magnetic dipole contributions, which correspond to the electric dipole and magnetic dipole transitions between the unperturbed quantum states. Remarkably, while the two kinds of rotatory strengths are of the same order of magnitude, the corresponding dissymmetry factors can differ bymore » a factor of 10{sup 5}. By maximizing the dissymmetry of magnetic dipole absorption one can significantly enhance the enantioselectivity in the interaction of semiconductor nanocrystals with circularly polarized light. This feature may advance chiral and analytical methods, which will benefit biophysics, chemistry, and pharmaceutical science. The developed theory is illustrated by an example of intraband transitions inside a semiconductor nanocuboid, whose rotatory strengths and dissymmetry factors are calculated analytically.« less

Optical activity of chirally distorted nanocrystals

NASA Astrophysics Data System (ADS)

Tepliakov, Nikita V.; Baimuratov, Anvar S.; Baranov, Alexander V.; Fedorov, Anatoly V.; Rukhlenko, Ivan D.

2016-05-01

We develop a general theory of optical activity of semiconductor nanocrystals whose chirality is induced by a small perturbation of their otherwise achiral electronic subsystems. The optical activity is described using the quantum-mechanical expressions for the rotatory strengths and dissymmetry factors introduced by Rosenfeld. We show that the rotatory strengths of optically active transitions are decomposed on electric dipole and magnetic dipole contributions, which correspond to the electric dipole and magnetic dipole transitions between the unperturbed quantum states. Remarkably, while the two kinds of rotatory strengths are of the same order of magnitude, the corresponding dissymmetry factors can differ by a factor of 105. By maximizing the dissymmetry of magnetic dipole absorption one can significantly enhance the enantioselectivity in the interaction of semiconductor nanocrystals with circularly polarized light. This feature may advance chiral and analytical methods, which will benefit biophysics, chemistry, and pharmaceutical science. The developed theory is illustrated by an example of intraband transitions inside a semiconductor nanocuboid, whose rotatory strengths and dissymmetry factors are calculated analytically.

Quark Yukawa pattern from spontaneous breaking of flavour SU(3) 3

NASA Astrophysics Data System (ADS)

Nardi, Enrico

2015-10-01

A SU(3)Q × SU(3)u × SU(3)d invariant scalar potential breaking spontaneously the quark flavour symmetry can explain the Standard Model flavour puzzle. The approximate alignment in flavour space of the vacuum expectation values of the up and down 'Yukawa fields' results as a dynamical effect. The observed quark mixing angles, the weak CP violating phase, and hierarchical quark masses can be all reproduced at the cost of introducing additional (auxiliary) scalar multiplets, but without the need of introducing hierarchical parameters.

Flavor preferences conditioned by oral monosodium glutamate in mice.

PubMed

Ackroff, Karen; Sclafani, Anthony

2013-11-01

The prototypic umami substance monosodium glutamate (MSG) reinforces preferences for its own flavor, as well as preferences for flavors associated with it, by conditioning processes. Mice of 3 inbred strains (C57BL/6J (B6), 129P3/J, and FVB/NJ) and 2 taste-knockout (KO) groups derived from the B6 lineage were initially indifferent to 200mM MSG, but this evaluation was altered by forced exposure to MSG. B6 and KO mice acquired an MSG preference, 129 mice remained indifferent, and FVB mice avoided MSG. The shifts in preference imply a postoral basis for MSG effects, suggesting that it could produce preferences for associated flavors. New mice were trained with a conditioned stimulus (CS+) flavor mixed in 200mM MSG and a CS- flavor in water. Similar to the parent B6 strain, mice missing the T1r3 element of an umami receptor or the downstream signaling component Trpm5 learned to prefer the CS+ flavor and subsequently showed similar preferences for MSG in an ascending concentration series. Consistent with their responses to forced exposure, the 129 strain did not acquire a significant CS+ preference, and the FVB strain avoided the CS+ flavor. The 129 and FVB strains showed little attraction in the ascending MSG concentration series. Together, these data indicate that the postoral effects of MSG can modulate responses to its own and MSG-paired flavors. The basis for strain differences in the responses to MSG is not certain, but the taste-signaling elements T1r3 and Trpm5, which are also present in the gut, are not required for mediation of this flavor learning.

On the flavor structure of natural composite Higgs models & top flavor violation

NASA Astrophysics Data System (ADS)

Azatov, Aleksandr; Panico, Giuliano; Perez, Gilad; Soreq, Yotam

2014-12-01

We explore the up flavor structure of composite pseudo Nambu-Goldstone-boson Higgs models, where we focus on the flavor anarchic minimal SO(5) case. We identify the different sources of flavor violation in this framework and emphasise the differences from the anarchic Randall-Sundrum scenario. In particular, the fact that the flavor symmetry does not commute with the symmetries that stabilize the Higgs potential may constrain the flavor structure of the theory. In addition, we consider the interplay between the fine tuning of the model and flavor violation. We find that generically the tuning of this class of models is worsen in the anarchic case due to the contributions from the additional fermion resonances. We show that, even in the presence of custodial symmetry, large top flavor violating rate are naturally expected. In particular, t → cZ branching ratio of order of 10-5 is generic for this class of models. Thus, this framework can be tested in the next run of the LHC as well as in other future colliders. We also find that the top flavor violation is weakly correlated with the increase amount of fine tuning. Finally, other related flavor violation effects, such as t → ch and in the D system, are found to be too small to be observed by the current and near future colliders.

Coactivation of Gustatory and Olfactory Signals in Flavor Perception

PubMed Central

Veldhuizen, Maria G.; Shepard, Timothy G.; Wang, Miao-Fen

2010-01-01

It is easier to detect mixtures of gustatory and olfactory flavorants than to detect either component alone. But does the detection of mixtures exceed the level predicted by probability summation, assuming independent detection of each component? To answer this question, we measured simple response times (RTs) to detect brief pulses of one of 3 flavorants (sucrose [gustatory], citral [olfactory], sucrose–citral mixture) or water, presented into the mouth by a computer-operated, automated flow system. Subjects were instructed to press a button as soon as they detected any of the 3 nonwater stimuli. Responses to the mixtures were faster (RTs smaller) than predicted by a model of probability summation of independently detected signals, suggesting positive coactivation (integration) of gustation and retronasal olfaction in flavor perception. Evidence for integration appeared mainly in the fastest 60% of the responses, indicating that integration arises relatively early in flavor processing. Results were similar when the 3 possible flavorants, and water, were interleaved within the same session (experimental condition), and when each flavorant was interleaved with water only (control conditions). This outcome suggests that subjects did not attend selectively to one flavor component or the other in the experimental condition and further supports the conclusion that (late) decisional or attentional strategies do not exert a large influence on the gustatory–olfactory flavor integration. PMID:20032112

Amino acid ionic liquids as chiral ligands in ligand-exchange chiral separations.

PubMed

Liu, Qian; Wu, Kangkang; Tang, Fei; Yao, Lihua; Yang, Fei; Nie, Zhou; Yao, Shouzhuo

2009-09-28

Recently, amino acid ionic liquids (AAILs) have attracted much research interest. In this paper, we present the first application of AAILs in chiral separation based on the chiral ligand exchange principle. By using 1-alkyl-3-methylimidazolium L-proline (L-Pro) as a chiral ligand coordinated with copper(II), four pairs of underivatized amino acid enantiomers-dl-phenylalanine (dl-Phe), dl-histidine (dl-His), dl-tryptophane (dl-Trp), and dl-tyrosine (dl-Tyr)-were successfully separated in two major chiral separation techniques, HPLC and capillary electrophoresis (CE), with higher enantioselectivity than conventionally used amino acid ligands (resolution (R(s))=3.26-10.81 for HPLC; R(s)=1.34-4.27 for CE). Interestingly, increasing the alkyl chain length of the AAIL cation remarkably enhanced the enantioselectivity. It was inferred that the alkylmethylimidazolium cations and L-Pro form ion pairs on the surface of the stationary phase or on the inner surface of the capillary. The ternary copper complexes with L-Pro are consequently attached to the support surface, thus inducing an ion-exchange type of retention for the dl-enantiomers. Therefore, the AAIL cation plays an essential role in the separation. This work demonstrates that AAILs are good alternatives to conventional amino acid ligands for ligand-exchange-based chiral separation. It also reveals the tremendous application potential of this new type of task-specific ILs.

SU(3) Landau gauge gluon and ghost propagators using the logarithmic lattice gluon field definition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilgenfritz, Ernst-Michael; Humboldt-Universitaet zu Berlin, Institut fuer Physik, 12489 Berlin; Menz, Christoph

2011-03-01

We study the Landau gauge gluon and ghost propagators of SU(3) gauge theory, employing the logarithmic definition for the lattice gluon fields and implementing the corresponding form of the Faddeev-Popov matrix. This is necessary in order to consistently compare lattice data for the bare propagators with that of higher-loop numerical stochastic perturbation theory. In this paper we provide such a comparison, and introduce what is needed for an efficient lattice study. When comparing our data for the logarithmic definition to that of the standard lattice Landau gauge we clearly see the propagators to be multiplicatively related. The data of themore » associated ghost-gluon coupling matches up almost completely. For the explored lattice spacings and sizes discretization artifacts, finite size, and Gribov-copy effects are small. At weak coupling and large momentum, the bare propagators and the ghost-gluon coupling are seen to be approached by those of higher-order numerical stochastic perturbation theory.« less

Three-Triplet Model with Double SU(3) Symmetry

DOE R&D Accomplishments Database

Han, M. Y.; Nambu, Y.

1965-01-01

With a view to avoiding some of the kinematical and dynamical difficulties involved in the single triplet quark model, a model for the low lying baryons and mesons based on three triplets with integral charges is proposed, somewhat similar to the two-triplet model introduced earlier by one of us (Y. N.). It is shown that in a U(3) scheme of triplets with integral charges, one is naturally led to three triplets located symmetrically about the origin of I{sub 3} - Y diagram under the constraint that Nishijima-Gell-Mann relation remains intact. A double SU(3) symmetry scheme is proposed in which the large mass splittings between different representations are ascribed to one of the SU(3), while the other SU(3) is the usual one for the mass splittings within a representation of the first SU(3).

Boundary stress tensor and asymptotically AdS3 non-Einstein spaces at the chiral point

NASA Astrophysics Data System (ADS)

Giribet, Gaston; Goya, Andrés; Leston, Mauricio

2011-09-01

Chiral gravity admits asymptotically AdS3 solutions that are not locally equivalent to AdS3; meaning that solutions do exist which, while obeying the strong boundary conditions usually imposed in general relativity, happen not to be Einstein spaces. In topologically massive gravity (TMG), the existence of non-Einstein solutions is particularly connected to the question about the role played by complex saddle points in the Euclidean path integral. Consequently, studying (the existence of) nonlocally AdS3 solutions to chiral gravity is relevant to understanding the quantum theory. Here, we discuss a special family of nonlocally AdS3 solutions to chiral gravity. In particular, we show that such solutions persist when one deforms the theory by adding the higher-curvature terms of the so-called new massive gravity. Moreover, the addition of higher-curvature terms to the gravity action introduces new nonlocally AdS3 solutions that have no analogues in TMG. Both stationary and time-dependent, axially symmetric solutions that asymptote AdS3 space without being locally equivalent to it appear. Defining the boundary stress tensor for the full theory, we show that these non-Einstein geometries have associated vanishing conserved charges.

Role of the strange quark in the rho(770) meson

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molina Peralta, Raquel; Guo, Dehua; Hu, B.

2017-03-01

Recently, the GWU lattice group has evaluated high-precision phase-shift data formore » $$\\pi\\pi$$ scattering in the $I = 1$, $J = 1$ channel. Unitary Chiral Perturbation Theory describes these data well around the resonance region and for different pion masses. Moreover, it allows to extrapolate to the physical point and estimate the effect of the missing $$K\\bar{K}$$ channel in the two-flavor lattice calculation. The absence of the strange quark in the lattice data leads to a lower $$\\rho$$ mass, and the analysis with U$$\\chi$$PT shows that the $$K \\bar{K}$$ channel indeed pushes the $$\\pi\\pi$$-scattering phase shift upward, having a surprisingly large effect on the $$\\rho$$-mass. The inelasticity is shown to be compatible with the experimental data. The analysis is then extended to all available two-flavor lattice simulations and similar mass shifts are observed. Chiral extrapolations of $$N_f = 2 + 1$$ lattice simulations for the $$\\rho(770)$$ are also reported.« less

Skew-flavored dark matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, Prateek; Chacko, Zackaria; Fortes, Elaine C. F. S.

We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects minimal flavor violation and is, therefore, naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in whichmore » dark matter couples to right-handed charged leptons. In large regions of parameter space, the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. In conclusion, these events exhibit a characteristic flavor pattern that may allow this class of models to be distinguished from other theories of dark matter.« less

Skew-flavored dark matter

DOE PAGES

Agrawal, Prateek; Chacko, Zackaria; Fortes, Elaine C. F. S.; ...

2016-05-10

We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects minimal flavor violation and is, therefore, naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in whichmore » dark matter couples to right-handed charged leptons. In large regions of parameter space, the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. In conclusion, these events exhibit a characteristic flavor pattern that may allow this class of models to be distinguished from other theories of dark matter.« less

The breaking of flavor democracy in the quark sector

NASA Astrophysics Data System (ADS)

Fritzsch, Harald; Xing, Zhi-Zhong; Zhang, Di

2017-09-01

The democracy of quark flavors is a well-motivated flavor symmetry, but it must be properly broken in order to explain the observed quark mass spectrum and flavor mixing pattern. We reconstruct the texture of flavor democracy breaking and evaluate its strength in a novel way, by assuming a parallelism between the Q=+2/3 and Q=-1/3 quark sectors and using a nontrivial parametrization of the flavor mixing matrix. Some phenomenological implications of such democratic quark mass matrices, including their variations in the hierarchy basis and their evolution from the electroweak scale to a super-high energy scale, are also discussed. Supported by National Natural Science Foundation of China (11375207) and National Basic Research Program of China (2013CB834300)

Flavor and taste of lansoprazole strawberry-flavored delayed-release oral suspension preferred over ranitidine peppermint-flavored oral syrup: in children aged between 5-11 years.

PubMed

Tolia, Vasundhara; Johnston, Gary; Stolle, Julie; Lee, Chang

2004-01-01

To compare the flavor and taste preference of two acid-inhibitory therapies in healthy children aged between 5-11 years. A single-site, single-blind, taste test trial was conducted in which 111 children participated after parental consent. One teaspoonful (5 mL) of lansoprazole delayed-release oral suspension (strawberry-flavored) and ranitidine oral syrup (peppermint-flavored) were provided to each child with a 10-minute break between samples. Children tasted the sample, swished it in their mouth for 10 seconds, and then expectorated the sample. Spring water and crackers were used to clear the palate between samples. After each sampling, children were observed for facial expressions and asked to rate their degree of liking of each sample based on a 5-point facial hedonic scale (5=like it very much, 1=dislike it very much). Likes, dislikes, and product preference were recorded. Of the 56 female and 54 male children who tasted both samples, 95% (105/110) preferred lansoprazole. Taste and flavor were the most often cited reasons for preferring lansoprazole (61 and 17 children, respectively) while three children preferred the flavor of ranitidine oral syrup. Lansoprazole received a higher mean liking rating compared with ranitidine (mean liking scores of 4.1 and 2.2, respectively). There was no significant difference in the preference for lansoprazole between age groups and gender with the degree of liking scores ranging between 3.5-4.4. Forty-two children disliked the texture of the lansoprazole oral suspension, citing the granules (31/110), thickness (7/110), or consistency/texture (4/110), specifically. After sampling both products, 95% of children preferred the flavor and taste of the strawberry-flavored lansoprazole delayed-release oral suspension compared with the peppermint-flavored ranitidine oral syrup.

Non-perturbative determination of cV, ZV and ZS/ZP in Nf = 3 lattice QCD

NASA Astrophysics Data System (ADS)

Heitger, Jochen; Joswig, Fabian; Vladikas, Anastassios; Wittemeier, Christian

2018-03-01

We report on non-perturbative computations of the improvement coefficient cV and the renormalization factor ZV of the vector current in three-flavour O(a) improved lattice QCD with Wilson quarks and tree-level Symanzik improved gauge action. To reduce finite quark mass effects, our improvement and normalization conditions exploit massive chiral Ward identities formulated in the Schrödinger functional setup, which also allow deriving a new method to extract the ratio ZS/ZP of scalar to pseudoscalar renormalization constants. We present preliminary results of a numerical evaluation of ZV and cV along a line of constant physics with gauge couplings corresponding to lattice spacings of about 0:09 fm and below, relevant for phenomenological applications.

On stability, chirality measures, and theoretical VCD spectra of the chiral C58X2 fullerenes (X = N, B).

PubMed

Ostrowski, Sławomir; Jamróz, Michał H; Rode, Joanna E; Dobrowolski, Jan Cz

2012-01-12

The stability of all 23 C(58)N(2) and C(58)B(2) heterofullerenes in the singlet and triplet states was determined at the B3LYP/6-31G** level. In equilibrium mixture the achiral (1,4) C(58)N(2) isomer would be populated in ca. 95.8%, the chiral (1,16) one in ca. 3.3%, and the achiral (1,4) C(58)B(2) in 100%, whereas all triplet state isomers are less stable. Fourteen out of 23 C(58)X(2) are chiral. Four different chirality measures were calculated by our own CHIMEA program: pure geometrical, labeled, mass, and charge. Intercorrelations between the measures for all chiral compounds indicate that the pure geometrical chirality measure is unstable and should not be used in QSAR predictions of the other molecular properties, while the labeled and mass-weighted ones are promising QSAR descriptors. For each chiral C(58)N(2) molecule, some very strong VCD bands, of intensity comparable with that in the IR spectra, can serve in identification and characterization of the isomers.

Lattice QCD with two dynamical flavors of domain wall fermions

NASA Astrophysics Data System (ADS)

Aoki, Y.; Blum, T.; Christ, N.; Dawson, C.; Hashimoto, K.; Izubuchi, T.; Laiho, J. W.; Levkova, L.; Lin, M.; Mawhinney, R.; Noaki, J.; Ohta, S.; Orginos, K.; Soni, A.

2005-12-01

We present results from the first large-scale study of two-flavor QCD using domain wall fermions (DWF), a chirally symmetric fermion formulation which has been proven to be very effective in the quenched approximation. We work on lattices of size 163×32, with a lattice cutoff of a-1≈1.7GeV and dynamical (or sea) quark masses in the range mstrange/2≲msea≲mstrange. After discussing the algorithmic and implementation issues involved in simulating dynamical DWF, we report on the low-lying hadron spectrum, decay constants, static quark potential, and the important kaon weak matrix element describing indirect CP violation in the standard model, BK. In the latter case we include the effect of nondegenerate quark masses (ms≠mu=md), finding BKM Smacr (2GeV)=0.495(18).

Flavor and flavor chemistry differences among milks processed by high-temperature, short-time pasteurization or ultra-pasteurization.

PubMed

Jo, Y; Benoist, D M; Barbano, D M; Drake, M A

2018-05-01

Typical high-temperature, short-time (HTST) pasteurization encompasses a lower heat treatment and shorter refrigerated shelf life compared with ultra-pasteurization (UP) achieved by direct steam injection (DSI-UP) or indirect heat (IND-UP). A greater understanding of the effect of different heat treatments on flavor and flavor chemistry of milk is required to characterize, understand, and identify the sources of flavors. The objective of this study was to determine the differences in the flavor and volatile compound profiles of milk subjected to HTST, DSI-UP, or IND-UP using sensory and instrumental techniques. Raw skim and raw standardized 2% fat milks (50 L each) were processed in triplicate and pasteurized at 78°C for 15 s (HTST) or 140°C for 2.3 s by DSI-UP or IND-UP. Milks were cooled and stored at 4°C, then analyzed at d 0, 3, 7, and 14. Sensory attributes were determined using a trained panel, and aroma active compounds were evaluated by solid-phase micro-extraction or stir bar sorptive extraction followed by gas chromatography-mass spectrometry, gas chromatography-olfactometry, and gas chromatography-triple quad mass spectrometry. The UP milks had distinct cooked and sulfur flavors compared with HTST milks. The HTST milks had less diversity in aroma active compounds compared with UP milks. Flavor intensity of all milks decreased by d 14 of storage. Aroma active compound profiles were affected by heat treatment and storage time in both skim and 2% milk. High-impact aroma active compounds were hydrogen sulfide, dimethyl trisulfide, and methional in DSI-UP and 2 and 3-methylbutanal, furfural, 2-heptanone, 2-acetyl-1-pyrroline, 2-aminoacetophenone, benzaldehyde, and dimethyl sulfide in IND-UP. These results provide a foundation knowledge of the effect of heat treatments on flavor development and differences in sensory quality of UP milks. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Five chiral Cd(II) complexes with dual chiral components: Effect of positional isomerism, luminescence and SHG response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Lin, E-mail: lcheng@seu.edu.cn; Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, Southeast University, Nanjing 211189; Wang, Jun

2015-01-15

Five chiral Cd(II) complexes with dual chiral components have been synthesized by using a series of (1R,2R)–N{sup 1},N{sup 2}-bis(pyridinylmethyl)cyclohexane-1,2-diamine ligands with different N-positions of pyridyl rings and Cd(NO{sub 3}){sub 2}. The circular dichroism (CD) spectra and second-harmonic generation (SHG) efficiency measurements confirmed that they are of structural chirality in the bulk samples. The luminescent properties indicated that they may have potential applications as optical materials. The formation of discrete mononuclear and binuclear complexes, and one-dimensional chains may be attributed to positional isomerism of the ligands. - Graphical abstract: Five chiral Cd(II) complexes with dual chiral components have been synthesized bymore » using a series of chiral ligands with different N-positions of pyridyl rings. - Highlights: • Five chiral Cd(II) complexes with dual chiral components have been synthesized. • CD spectra and SHG efficiency of the bulk samples have been measured. • The complexes display luminescent properties.« less

Chiral 1,2- and 1,3-diol-functionalized chromophores as Lego building blocks for coupled structures.

PubMed

Spange, Stefan; Hofmann, Katja; Walfort, Bernhard; Rüffer, Tobias; Lang, Heinrich

2005-10-14

Chiral nitroanilines containing 1,2- or 1,3-diol functionalities have been synthesized by nucleophilic aromatic substitution of fluoronitroanilines with 1-aminopropane-2,3-diols and 2-aminopropane-1,3-diol in the melt. X-ray structure analyses confirm retention of the configuration of the chiral center. The novel chromophores are suitable to link reversibly to various substituted arylboronic acids which allows the construction of new solvatochromic sensor molecules suitable to response to solvent and anion coordination by fluoride. The solvatochromism of the new compounds has been studied using the Kamlet-Taft LSE relationship.

On chirality transfer in electron donor-acceptor complexes. A prediction for the sulfinimine···BF3 system.

PubMed

Rode, Joanna E; Dobrowolski, Jan Cz

2012-01-01

Stabilization energies of the electron donor-acceptor sulfinimine···BF(3) complexes calculated at either the B3LYP/aug-cc-pVTZ or the MP2/aug-cc-pVTZ level do not allow to judge, whether the N- or O-atom in sulfinimine is stronger electron-donor to BF(3) . The problem seems to be solvable because chirality transfer phenomenon between chiral sulfinimine and achiral BF(3) is expected to be vibrational circular dichroism (VCD) active. Moreover, the bands associated with the achiral BF(3) molecule are predicted to be the most intense in the entire spectrum. However, the VCD band robustness analyses show that most of the chirality transfer modes of BF(3) are unreliable. Conversely, variation of VCD intensity with change of intermolecular distance, angle, and selected dihedrals between the complex partners shows that to establish the robustness of chirality transfer mode. It is also necessary to determine the influence of the potential energy surface (PES) shape on the VCD intensity. At the moment, there is still no universal criterion for the chirality transfer mode robustness and the conclusions formulated based on one system cannot be directly transferred even to a quite similar one. However, it is certain that more attention should be focused on relation of PES shape and the VCD mode robustness problem. Copyright © 2011 Wiley Periodicals, Inc.

The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calle Cordon, Alvaro C.; DeGrand, Thomas A.; Goity, Jose L.

Baryon masses at varying values of Nc and light quark masses are studied with Lattice QCD and the results are analyzed in a low energy effective theory based on a combined framework of the 1/Nc and Heavy Baryon Chiral Perturbation Theory expansions. Lattice QCD results for Nc=3, 5 and 7 obtained in quenched calculations, as well as results for unquenched calculations for Nc=3, are used for the analysis. The results are consistent with a previous analysis of Nc=3 LQCD results, and in addition permit the determination of sub-leading in 1/Nc effects in the spin-flavor singlet component of the baryon massesmore » as well as in the hyperfine splittings.« less

Lattice QCD spectroscopy for hadronic CP violation

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Vries, Jordy; Mereghetti, Emanuele; Seng, Chien -Yeah

Here, the interpretation of nuclear electric dipole moment (EDM) experiments is clouded by large theoretical uncertainties associated with nonperturbative matrix elements. In various beyond-the-Standard Model scenarios nuclear and diamagnetic atomic EDMs are expected to be dominated by CP-violating pion–nucleon interactions that arise from quark chromo-electric dipole moments. The corresponding CP-violating pion–nucleon coupling strengths are, however, poorly known. In this work we propose a strategy to calculate these couplings by using spectroscopic lattice QCD techniques. Instead of directly calculating the pion–nucleon coupling constants, a challenging task, we use chiral symmetry relations that link the pion–nucleon couplings to nucleon sigma terms andmore » mass splittings that are significantly easier to calculate. In this work, we show that these relations are reliable up to next-to-next-to-leading order in the chiral expansion in both SU(2) and SU(3) chiral perturbation theory. We conclude with a brief discussion about practical details regarding the required lattice QCD calculations and the phenomenological impact of an improved understanding of CP-violating matrix elements.« less

Lattice QCD spectroscopy for hadronic CP violation

DOE PAGES

de Vries, Jordy; Mereghetti, Emanuele; Seng, Chien -Yeah; ...

2017-01-16

Here, the interpretation of nuclear electric dipole moment (EDM) experiments is clouded by large theoretical uncertainties associated with nonperturbative matrix elements. In various beyond-the-Standard Model scenarios nuclear and diamagnetic atomic EDMs are expected to be dominated by CP-violating pion–nucleon interactions that arise from quark chromo-electric dipole moments. The corresponding CP-violating pion–nucleon coupling strengths are, however, poorly known. In this work we propose a strategy to calculate these couplings by using spectroscopic lattice QCD techniques. Instead of directly calculating the pion–nucleon coupling constants, a challenging task, we use chiral symmetry relations that link the pion–nucleon couplings to nucleon sigma terms andmore » mass splittings that are significantly easier to calculate. In this work, we show that these relations are reliable up to next-to-next-to-leading order in the chiral expansion in both SU(2) and SU(3) chiral perturbation theory. We conclude with a brief discussion about practical details regarding the required lattice QCD calculations and the phenomenological impact of an improved understanding of CP-violating matrix elements.« less

Chiral geometry in multiple chiral doublet bands

NASA Astrophysics Data System (ADS)

Zhang, Hao; Chen, Qibo

2016-02-01

The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with . The energy spectra, electromagnetic transition probabilities B(M1) and B(E2), angular momenta, and K-distributions are studied. It is demonstrated that the chirality still remains not only in the yrast and yrare bands, but also in the two higher excited bands when γ deviates from 30°. The chiral geometry relies significantly on γ, and the chiral geometry of the two higher excited partner bands is not as good as that of the yrast and yrare doublet bands. Supported by Plan Project of Beijing College Students’ Scientific Research and Entrepreneurial Action, Major State 973 Program of China (2013CB834400), National Natural Science Foundation of China (11175002, 11335002, 11375015, 11461141002), National Fund for Fostering Talents of Basic Science (NFFTBS) (J1103206), Research Fund for Doctoral Program of Higher Education (20110001110087) and China Postdoctoral Science Foundation (2015M580007)

Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

PubMed Central

Jiang, Wenge; Pacella, Michael S.; Athanasiadou, Dimitra; Nelea, Valentin; Vali, Hojatollah; Hazen, Robert M.; Gray, Jeffrey J.; McKee, Marc D.

2017-01-01

Chirality is ubiquitous in biology, including in biomineralization, where it is found in many hardened structures of invertebrate marine and terrestrial organisms (for example, spiralling gastropod shells). Here we show that chiral, hierarchically organized architectures for calcium carbonate (vaterite) can be controlled simply by adding chiral acidic amino acids (Asp and Glu). Chiral, vaterite toroidal suprastructure having a ‘right-handed' (counterclockwise) spiralling morphology is induced by L-enantiomers of Asp and Glu, whereas ‘left-handed' (clockwise) morphology is induced by D-enantiomers, and sequentially switching between amino-acid enantiomers causes a switch in chirality. Nanoparticle tilting after binding of chiral amino acids is proposed as a chiral growth mechanism, where a ‘mother' subunit nanoparticle spawns a slightly tilted, consequential ‘daughter' nanoparticle, which by amplification over various length scales creates oriented mineral platelets and chiral vaterite suprastructures. These findings suggest a molecular mechanism for how biomineralization-related enantiomers might exert hierarchical control to form extended chiral suprastructures. PMID:28406143

Further Comments on a Vanishing Singlet Axial Vector Charge

NASA Astrophysics Data System (ADS)

Cheng, T. P.; Kochelev, N. I.; Vento, Vicente

The recent suggestion of a vanishing flavor-singlet axial-charge of nucleon due to a nontrivial vacuum structure is further amplified. A perturbative QCD discussion, applicable for the heavy quark contributions, relates it to the physics of the decoupling theorem. It is also shown that gA0˜= 0 leads to a negative η‧-meson-quark coupling, which has been found to be compatible with the chiral quark model phenomenology.

Microsomal Oxidation of 2,2′,3,3′,6,6′-Hexachlorobiphenyl (PCB 136) Results in Species-Dependent Chiral Signatures of the Hydroxylated Metabolites

PubMed Central

2015-01-01

Chiral polychlorinated biphenyls (PCBs) display variable atropisomeric enrichment in wildlife and animal models, especially at higher trophic levels. These differences in PCBs’ chiral signatures are, at least in part, due to species-dependent oxidation of PCBs to hydroxylated PCB metabolites (OH-PCBs). Here, we investigate the hypothesis that the cytochrome P450 (P450) enzyme-mediated oxidation of chiral PCBs results in species-dependent differences in the chiral signatures of OH-PCBs (i.e., the direction and extent of OH-PCBs’ atropisomeric enrichment). To investigate this hypothesis, we incubated PCB 136, a representative chiral PCB, with pooled human liver microsomes (HLMs) or liver microsomes from male guinea pig, hamster, monkey, mouse, and rabbit or female dog and determined average profiles and chiral signatures of the OH-PCBs. 2,2′,3,3′,6,6′-Hexachlorobiphenyl-4-ol (4–136) was the major metabolite in incubations with HLMs and monkey and rabbit microsomes. 2,2′,3,3′,6,6′-Hexachlorobiphenyl-5-ol (5–136) was the major metabolite formed by microsomes from all other species. Both 4–136 and 5–136 were formed atropselectively in all microsomal incubations; however, the direction and extent of the atropisomeric enrichment of both OH-PCB metabolites showed considerable differences across microsomal preparations obtained from different species. These differences in OH-PCBs’ atropisomeric enrichment may not only be toxicologically relevant but may also be useful to study sources and transport of OH-PCBs in the environment. PMID:24467194

Flavor Programming During Infancy

PubMed Central

Griffin, Cara E.; Beauchamp, Gary K.

2005-01-01

Objective. Although individuals differ substantially in their flavor and food preferences, the source of such differences remains a mystery. The present experimental study was motivated by clinical observations that early experience with formulas establishes subsequent preferences. Design. Infants whose parents had chosen to formula-feed them were randomized into 1 of 4 groups by the second week of life. One group was assigned to be fed a milk-based formula (Enfamil), whereas another was assigned to be fed (Nutramigen), a particularly unpleasant-tasting protein hydrolysate formula. The remaining groups were assigned to be fed Nutramigen for 3 months and Enfamil for 4 months; the timing of exposure differed between the groups. After 7 months of exposure, infants were videotaped on 3 separate days while feeding, in counterbalanced order, Enfamil, Nutramigen, and Alimentum, a novel hydrolysate formula. Results. For each of the 4 interrelated measures of behavior (intake, duration of formula feeding, facial expressions, and mothers’ judgments of infant acceptance), previous exposure to Nutramigen significantly enhanced subsequent acceptance of both Nutramigen and Alimentum. Seven months of exposure led to greater acceptance than did 3 months. Conclusions. The bases for clinical difficulties in introducing hydrolysate formulas during older infancy are clarified in this study. More broadly, variation in formula flavor provided a useful model for demonstrating experimentally the effects of long-term exposure differences on later acceptance. Such early variation, under more species-typical circumstances (eg, via exposure to different flavors in amniotic fluid and mothers’ milk), may underlie individual differences in food acceptability throughout the life span. Pediatrics 2004;113:840–845; protein hydrolysate, formula, taste, flavor, infants, programming, development, nutrition. PMID:15060236

Chirality measures of α-amino acids.

PubMed

Jamróz, Michał H; Rode, Joanna E; Ostrowski, Sławomir; Lipiński, Piotr F J; Dobrowolski, Jan Cz

2012-06-25

To measure molecular chirality, the molecule is treated as a finite set of points in the Euclidean R(3) space supplemented by k properties, p(1)((i)), p(2)((i)), ..., p(k)((i)) assigned to the ith atom, which constitute a point in the Property P(k) space. Chirality measures are described as the distance between a molecule and its mirror image minimized over all its arbitrary orientation-preserving isometries in the R(3) × P(k) Cartesian product space. Following this formalism, different chirality measures can be estimated by taking into consideration different sets of atomic properties. Here, for α-amino acid zwitterionic structures taken from the Cambridge Structural Database and for all 1684 neutral conformers of 19 biogenic α-amino acid molecules, except glycine and cystine, found at the B3LYP/6-31G** level, chirality measures have been calculated by a CHIMEA program written in this project. It is demonstrated that there is a significant correlation between the measures determined for the α-amino acid zwitterions in crystals and the neutral forms in the gas phase. Performance of the studied chirality measures with changes of the basis set and computation method was also checked. An exemplary quantitative structure–activity relationship (QSAR) application of the chirality measures was presented by an introductory model for the benchmark Cramer data set of steroidal ligands of the sex-hormone binding globulin.

Neutron and proton electric dipole moments from N f=2+1 domain-wall fermion lattice QCD

DOE PAGES

Shintani, Eigo; Blum, Thomas; Izubuchi, Taku; ...

2016-05-05

We present a lattice calculation of the neutron and proton electric dipole moments (EDM’s) with N f = 2 + 1 flavors of domain-wall fermions. The neutron and proton EDM form factors are extracted from three-point functions at the next-to-leading order in the θ vacuum of QCD. In this computation, we use pion masses 330 and 420 MeV and 2.7 fm 3 lattices with Iwasaki gauge action and a 170 MeV pion and 4.6 fm 3 lattice with I-DSDR gauge action, all generated by the RBC and UKQCD collaborations. The all-mode-averaging technique enables an efficient, high statistics calculation; however themore » statistical errors on our results are still relatively large, so we investigate a new direction to reduce them, reweighting with the local topological charge density which appears promising. Furthermore, we discuss the chiral behavior and finite size effects of the EDM’s in the context of baryon chiral perturbation theory.« less

Enantiomeric separation of six chiral pesticides that contain chiral sulfur/phosphorus atoms by supercritical fluid chromatography.

PubMed

Zhang, Lijun; Miao, Yelong; Lin, Chunmian

2018-03-01

Six chiral pesticides containing chiral sulfur/phosphorus atoms were separated by supercritical fluid chromatography with supercritical CO 2 as the main mobile phase component. The effect of the chiral stationary phase, different type and concentration of modifiers, column temperature, and backpressure on the separation efficiency was investigated to obtain the appropriate separation condition. Five chiral pesticides (isofenphos-methyl, isocarbophos, flufiprole, fipronil, and ethiprole) were baseline separated under experimental conditions, while isofenphos only obtained partial separation. The Chiralpak AD-3 column showed a better chiral separation ability than others for chiral pesticides containing chiral sulfur/phosphorus atoms. When different modifiers at the same concentration were used, the retention factor of pesticides except flufiprole decreased in the order of isopropanol, ethanol, methanol; meanwhile, the retention factor of flufiprole increased in the order of isopropanol, ethanol, methanol. For a given modifier, the retention factor and resolution decreased on the whole with the increase of its concentration. The enantiomer separation of five chiral pesticides was an "enthalpy-driven" process, and the separation factor decreased as the temperature increased. The backpressure of the mobile phase had little effect on the separation factor and resolution. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assembly of chiral molecular polygons.

PubMed

Jiang, Hua; Lin, Wenbin

2003-07-09

Treatment of 2,2'-diacetyl-1,1'-binaphthyl-6,6'-bis(ethyne), L-H2, with 1 equiv of trans-Pt(PEt3)2Cl2 led to a mixture of different sizes of chiral metallocycles [trans-(PEt3)2Pt(L)]n (n = 3-8, 1-6). Each of the chiral molecular polygons 1-6 was purified by silica gel column chromatography and characterized by 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, MS, IR, UV-vis, and circular dichroism spectroscopies, and microanalysis. The presence of tunable cavities (1.4-4.3 nm) and chiral functionalities in these molecular polygons promises to make them excellent receptors for a variety of guests.

The QCD matter; perturbation and lattice gauge theory

NASA Astrophysics Data System (ADS)

Saini, Abhilasha; Bhardwaj, Sudhir; Keswani, Bright

2018-05-01

In this review we are watching towards the probes of quark gluon plasma which provides the unique option to create such nuclear stuff at controlled laboratory conditions. The observables from hadronic and leptonic residues provide the required information. The other tool is the detailed rapidity and momentum spectra of hadrons. Here the information regarding the de-confined phase transition and chiral symmetry restoration is mentioned; also the perturbation and lattice gauge theory is described in short.

Chiral plaquette polaron theory of cuprate superconductivity

NASA Astrophysics Data System (ADS)

Tahir-Kheli, Jamil; Goddard, William A., III

2007-07-01

Ab initio density functional calculations on explicitly doped La2-xSrxCuO4 find that doping creates localized holes in out-of-plane orbitals. A model for cuprate superconductivity is developed based on the assumption that doping leads to the formation of holes on a four-site Cu plaquette composed of the out-of-plane A1 orbitals apical Opz , planar Cud3z2-r2 , and planar Opσ . This is in contrast to the assumption of hole doping into planar Cudx2-y2 and Opσ orbitals as in the t-J model. Allowing these holes to interact with the d9 spin background leads to chiral polarons with either a clockwise or anticlockwise charge current. When the polaron plaquettes percolate through the crystal at x≈0.05 for La2-xSrxCuO4 , a Cudx2-y2 and planar Opσ band is formed. The computed percolation doping of x≈0.05 equals the observed transition to the “metallic” and superconducting phase for La2-xSrxCuO4 . Spin exchange Coulomb repulsion with chiral polarons leads to d -wave superconducting pairing. The equivalent of the Debye energy in phonon superconductivity is the maximum energy separation between a chiral polaron and its time-reversed partner. This energy separation is on the order of the antiferromagnetic spin coupling energy, Jdd˜0.1eV , suggesting a higher critical temperature. An additive skew-scattering contribution to the Hall effect is induced by chiral polarons and leads to a temperature dependent Hall effect that fits the measured values for La2-xSrxCuO4 . The integrated imaginary susceptibility, observed by neutron spin scattering, satisfies ω/T scaling due to chirality and spin-flip scattering of polarons along with a uniform distribution of polaron energy splittings. The derived functional form is compatible with experiments. The static spin structure factor for chiral spin coupling of the polarons to the undoped antiferromagnetic Cud9 spins is computed for classical spins on large two-dimensional lattices and is found to be incommensurate with a

Improved perturbative QCD formalism for Bc meson decays

NASA Astrophysics Data System (ADS)

Liu, Xin; Li, Hsiang-nan; Xiao, Zhen-Jun

2018-06-01

We derive the kT resummation for doubly heavy-flavored Bc meson decays by including the charm quark mass effect into the known formula for a heavy-light system. The resultant Sudakov factor is employed in the perutrbative QCD study of the "golden channel" Bc+→J /ψ π+. With a reasonable model for the Bc meson distribution amplitude, which maintains approximate on-shell conditions of both the partonic bottom and charm quarks, it is observed that the imaginary piece of the Bc→J /ψ transition form factor appears to be power suppressed, and the Bc+→J /ψ π+ branching ratio is not lower than 10-3. The above improved perturbative QCD formalism is applicable to Bc meson decays to other charmonia and charmed mesons.

Neutrinos and flavor symmetries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanimoto, Morimitsu

2015-07-15

We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ{sub 13} and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ{sub 13} is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.

Topological susceptibility of QCD with dynamical Möbius domain-wall fermions

NASA Astrophysics Data System (ADS)

Aoki, S.; Cossu, G.; Fukaya, H.; Hashimoto, S.; Kaneko, T.

2018-04-01

We compute the topological susceptibility χ_t of lattice QCD with 2+1 dynamical quark flavors described by the Möbius domain-wall fermion. Violation of chiral symmetry as measured by the residual mass is kept at ˜1 MeV or smaller. We measure the fluctuation of the topological charge density in a "slab" sub-volume of the simulated lattice using the method proposed by W. Bietenholz, P. de Forcrand, and U. Gerber, J. High Energy Phys. 12, 070 (2015) and W. Bietenholz, K. Cichy, P. de Forcrand, A. Dromard, and U. Gerber, PoS LATTICE 2016, 321 (2016). The quark mass dependence of χ_t is consistent with the prediction of chiral perturbation theory, from which the chiral condensate is extracted as Σ^{\\overlineMS}(2 GeV) = [274(13)(29) MeV]^3, where the first error is statistical and the second one is systematic. Combining the results for the pion mass M_π and decay constant F_π, we obtain χ_t = 0.229(03)(13)M_π^2F_π^2 at the physical point.

A 3D chiral metal-organic framework based on left-handed helices containing 3-amino-1 H-1,2,4-triazole ligand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Bing, E-mail: bliu_1203@163.com; Yang, Tian-Yi; Feng, Hui-Jun

2015-10-15

A chiral metal-organic framework, [Cu(atr)(OH)]·0.5H{sub 2}O·0.5en (1) (Hatr=3-amino-1 H-1,2,4-triazole, en=ethylenediamine), was constructed via diffusion reaction of the achiral Hatr ligand and CuSO{sub 4} as starting materials. Compound 1 crystallizes in the chiral space group P3{sub 2}21 and features a porous metal-organic framework with 44.1% solvent-accessible volume fabricated by left-handed helices with a pitch height of l{sub p}=10.442 Å. Six helices gather around in a cycle forming a large honeycomb channel with a 6.58 Å inner diameter. Cu(II) center and atr{sup ‒} ligand regarded as 3-connected nodes, compound 1 can be simplified to a 3-c uninodal (4.12{sup 2}) (qtz-h) topological network.more » A gradual decreasing in the magnetic moment depending on temperature decreasing indicates an antiferromagnetic interaction in 1. The powder XRD confirms the bulk sample is a single crystal pure phase, and the thermogravimetric analysis shows the thermal stability of 1 is up to ca. 240 °C. - Highlights: • The present 3D chiral MOF is built from achiral Hatr ligand. • Six left-handed helices gather into a honeycomb channel in chiral sp P3{sub 2}21. • Compound 1 shows a 3-c uninodal (4.12{sup 2}) or qtz-h topological network. • Compound 1 indicates an antiferromagnetic interaction.« less

Enantioseparation and optical rotation of flavor-relevant 4-alkyl-branched fatty acids.

PubMed

Eibler, Dorothee; Vetter, Walter

2017-07-07

Short chain 4-alkyl-branched fatty acids are character impact compounds of the flavor of sheep and goat milk and meat. Due to their methyl or ethyl branches these volatile fatty acids are chiral, and both enantiomers are characterized by different aroma intensities. Recently, it was found that 4-methyloctanoic acid (4-Me-8:0), 4-ethyloctanoic acid (4-Et-8:0), and 4-methylnonanoic acid (4-Me-9:0) are enantiopure in goat and sheep samples, if present. Here we generated enantiopure or enantioenriched standards from racemates by means of (R)-selective esterification with lipase B and verified that 4-Me-8:0, 4-Et-8:0 and 4-Me-9:0 were (R)-enantiopure in these tissues. Determination of the optical rotation and [α] D value was carried out to show that (R)-4-Et-8:0 is dextrorotary and to verify the literature values of (R)-4-methyl-branched fatty acids. The elution order of free acids and the methyl and ethyl esters of 4-Me-8:0, 4-Et-8:0, 4-Me-9:0 and 4-methylhexanoic acid (4-Me-6:0) enantiomers was investigated on different chiral columns as well as the (-)-menthyl ester by indirect enantiomer separation on an ionic liquid phase. Different chiral recognition processes were suggested for free acid and esters of 4-Me-8:0 and 4-Me-9:0 on the one hand (decisive: 4-alkyl branch) compared to 4-Me-6:0 on the other hand (decisive: branch on antepenultimate carbon). Copyright © 2017 Elsevier B.V. All rights reserved.

Chiral topological insulator of magnons

NASA Astrophysics Data System (ADS)

Li, Bo; Kovalev, Alexey A.

2018-05-01

We propose a magnon realization of 3D topological insulator in the AIII (chiral symmetry) topological class. The topological magnon gap opens due to the presence of Dzyaloshinskii-Moriya interactions. The existence of the topological invariant is established by calculating the bulk winding number of the system. Within our model, the surface magnon Dirac cone is protected by the sublattice chiral symmetry. By analyzing the magnon surface modes, we confirm that the backscattering is prohibited. By weakly breaking the chiral symmetry, we observe the magnon Hall response on the surface due to opening of the gap. Finally, we show that by changing certain parameters, the system can be tuned between the chiral topological insulator, three-dimensional magnon anomalous Hall, and Weyl magnon phases.

Perturbative search for dead-end CFTs

DOE PAGES

Nakayama, Yu

2015-05-08

To explore the possibility of self-organized criticality, we look for CFTs without any relevant scalar deformations (a.k.a. dead-end CFTs) within power-counting renormalizable quantum field theories with a weakly coupled Lagrangian description. In three dimensions, the only candidates are pure (Abelian) gauge theories, which may be further deformed by Chern-Simons terms. In four dimensions, we show that there are infinitely many non-trivial candidates based on chiral gauge theories. Using the three-loop beta functions, we compute the gap of scaling dimensions above the marginal value, and it can be as small as O(10 –5) and robust against the perturbative corrections. These classesmore » of candidates are very weakly coupled and our perturbative conclusion seems difficult to refute. Furthermore, the hypothesis that non-trivial dead-end CFTs do not exist is likely to be false in four dimensions.« less

Perturbative search for dead-end CFTs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakayama, Yu

To explore the possibility of self-organized criticality, we look for CFTs without any relevant scalar deformations (a.k.a. dead-end CFTs) within power-counting renormalizable quantum field theories with a weakly coupled Lagrangian description. In three dimensions, the only candidates are pure (Abelian) gauge theories, which may be further deformed by Chern-Simons terms. In four dimensions, we show that there are infinitely many non-trivial candidates based on chiral gauge theories. Using the three-loop beta functions, we compute the gap of scaling dimensions above the marginal value, and it can be as small as O(10 –5) and robust against the perturbative corrections. These classesmore » of candidates are very weakly coupled and our perturbative conclusion seems difficult to refute. Furthermore, the hypothesis that non-trivial dead-end CFTs do not exist is likely to be false in four dimensions.« less

An E-liquid Flavor Wheel: A Shared Vocabulary based on Systematically Reviewing E-liquid Flavor Classifications in Literature.

PubMed

Krüsemann, Erna Johanna Zegerina; Boesveldt, Sanne; de Graaf, Kees; Talhout, Reinskje

2018-05-18

E-liquids are available in a high variety of flavors. A systematic classification of e-liquid flavors is necessary to increase comparability of research results. In the food, alcohol and fragrance industry, flavors are classified using flavor wheels. We systematically reviewed literature on flavors related to e-cigarette use, to investigate how e-liquid flavors have been classified in research, and propose an e-liquid flavor wheel to classify e-liquids based on marketing descriptions. The search was conducted in May 2017 using PubMed and Embase databases. Keywords included terms associated with e-cigarettes, flavors, liking, learning, and wanting in articles. Results were independently screened and reviewed. Flavor categories used in the articles reviewed were extracted. Searches yielded 386 unique articles of which 28 were included. Forty-three main flavor categories were reported in these articles (e.g., tobacco, menthol, mint, fruit, bakery/dessert, alcohol, nuts, spice, candy, coffee/tea, beverages, chocolate, sweet flavors, vanilla, unflavored). Flavor classifications of e-liquids in literature showed similarities and differences across studies. Our proposed e-liquid flavor wheel contains 13 main categories and 90 subcategories, which summarize flavor categories from literature to find a shared vocabulary. For classification of e-liquids using our flavor wheel, marketing descriptions should be used. We have proposed a flavor wheel for classification of e-liquids. Further research is needed to test the flavor wheels' empirical value. Consistently classifying e-liquid flavors using our flavor wheel in research (e.g., experimental, marketing, or qualitative studies) minimizes interpretation differences and increases comparability of results. We reviewed e-liquid flavors and flavor categories used in research. A large variation in the naming of flavor categories was found and e-liquid flavors were not consistently classified. We developed an e-liquid flavor wheel

Alternative [SU(3)]4 model of leptonic color and dark matter

NASA Astrophysics Data System (ADS)

Kownacki, Corey; Ma, Ernest; Pollard, Nicholas; Popov, Oleg; Zakeri, Mohammadreza

2018-03-01

The alternative [ SU (3) ] 4 model of leptonic color and dark matter is discussed. It unifies at MU ∼1014 GeV and has the low-energy subgroup SU(3)q × SU(2)l × SU(2)L × SU(2)R × U(1)X with (u , h) R instead of (u , d) R as doublets under SU(2)R. It has the built-in global U (1) dark symmetry which is generalized B- L. In analogy to SU(3)q quark triplets, it has SU(2)l hemion doublets which have half-integral charges and are confined by SU(2)l gauge bosons (stickons). In analogy to quarkonia, their vector bound states (hemionia) are uniquely suited for exploration at a future e-e+ collider.

Chiral magnetic effect in condensed matter systems

DOE PAGES

Li, Qiang; Kharzeev, Dmitri E.

2016-12-01

The chiral magnetic effect is the generation of electrical current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum anomaly in relativistic field theory of chiral fermions. In the quark-gluon plasma, the axial anomaly induces topological charge changing transition that results in the generation of electrical current along the magnetic field. In condensed matter systems, the chiral magnetic effect was first predicted in the gapless semiconductors with tow energy bands having pointlike degeneracies. In addition, thirty years later after this prediction, the chiral magnetic effect was finally observed in the 3Dmore » Dirac/Weyl semimetals.« less

Multiple critical endpoints in magnetized three flavor quark matter

NASA Astrophysics Data System (ADS)

Ferreira, Márcio; Costa, Pedro; Providência, Constança

2018-01-01

The magnetized phase diagram for three-flavor quark matter is studied within the Polyakov extended Nambu-Jona-Lasinio model. The order parameters are analyzed with special emphasis on the strange quark condensate. We show that the presence of an external magnetic field induces several critical endpoints (CEPs) in the strange sector, which arise due to the multiple phase transitions that the strange quark undergoes. The spinodal and binodal regions of the phase transitions are shown to increase with external magnetic field strength. The influence of strong magnetic fields on the isentropic trajectories around the several CEPs is analyzed. A focusing effect is observed on the region towards the CEPs that are related with the strange quark phase transitions. Compared to the chiral transitions, the deconfinement transition turns out to be less sensitive to the external magnetic field and the crossover nature is preserved over the whole phase diagram.

Effects of nonequilibrated topological charge distributions on pseudoscalar meson masses and decay constants

NASA Astrophysics Data System (ADS)

Bernard, C.; Toussaint, D.

2018-04-01

We study the effects of failure to equilibrate the squared topological charge Q2 on lattice calculations of pseudoscalar masses and decay constants. The analysis is based on chiral perturbation theory calculations of the dependence of these quantities on the QCD vacuum angle θ . For the light-light partially quenched case, we rederive the known chiral perturbation theory results of Aoki and Fukaya, but using the nonperturbatively valid chiral theory worked out by Golterman, Sharpe and Singleton, and by Sharpe and Shoresh. We then extend these calculations to heavy-light mesons. Results when staggered taste violations are important are also presented. The derived Q2 dependence is compared to that of simulations using the MILC Collaboration's ensembles of lattices with four flavors of dynamical highly improved staggered quarks. We find agreement, albeit with large statistical errors. These results can be used to correct for the leading effects of unequilibrated Q2, or to make estimates of the systematic error coming from the failure to equilibrate Q2. In an appendix, we show that the partially quenched chiral theory may be extended beyond a lower bound on valence masses discovered by Sharpe and Shoresh. Subtleties occurring when a sea-quark mass vanishes are discussed in another appendix.

Electric line source illumination of a chiral cylinder placed in another chiral background medium

NASA Astrophysics Data System (ADS)

Aslam, M.; Saleem, A.; Awan, Z. A.

2018-05-01

An electric line source illumination of a chiral cylinder embedded in a chiral background medium is considered. The field expressions inside and outside of a chiral cylinder have been derived using the wave field decomposition approach. The effects of various chiral cylinders, chiral background media and source locations upon the scattering gain pattern have been investigated. It is observed that the chiral background reduces the backward scattering gain as compared to the free space background for a dielectric cylinder. It is also studied that by moving a line source away from a cylinder reduces the backward scattering gain for a chiral cylinder placed in a chiral background under some specific conditions. A unique phenomenon of reduced scattering gain has been observed at a specific observation angle for a chiral cylinder placed in a chiral background having an electric line source location of unity free space wavelength. An isotropic scattering gain pattern is observed for a chiral nihility background provided that if cylinder is chiral or chiral nihility type. It is also observed that this isotropic behaviour is independent of background and cylinder chirality.

B → Dℓν form factors at nonzero recoil and |V cb| from 2+1-flavor lattice QCD

DOE PAGES

Bailey, Jon A.

2015-08-10

We present the first unquenched lattice-QCD calculation of the hadronic form factors for the exclusive decay B¯→Dℓν¯ at nonzero recoil. We carry out numerical simulations on 14 ensembles of gauge-field configurations generated with 2+1 flavors of asqtad-improved staggered sea quarks. The ensembles encompass a wide range of lattice spacings (approximately 0.045 to 0.12 fm) and ratios of light (up and down) to strange sea-quark masses ranging from 0.05 to 0.4. For the b and c valence quarks we use improved Wilson fermions with the Fermilab interpretation, while for the light valence quarks we use asqtad-improved staggered fermions. We extrapolate ourmore » results to the physical point using rooted staggered heavy-light meson chiral perturbation theory. We then parametrize the form factors and extend them to the full kinematic range using model-independent functions based on analyticity and unitarity. We present our final results for f +(q 2) and f 0(q 2), including statistical and systematic errors, as coefficients of a series in the variable z and the covariance matrix between these coefficients. We then fit the lattice form-factor data jointly with the experimentally measured differential decay rate from BABAR to determine the CKM matrix element, |V cb|=(39.6 ± 1.7 QCD+exp ± 0.2 QED) × 10 –3. As a byproduct of the joint fit we obtain the form factors with improved precision at large recoil. In conclusion, we use them to update our calculation of the ratio R(D) in the Standard Model, which yields R(D)=0.299(11).« less

Probing deconfinement in a chiral effective model with Polyakov loop at imaginary chemical potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morita, Kenji; Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502; Skokov, Vladimir

2011-10-01

The phase structure of the two-flavor Polyakov-loop extended Nambu-Jona-Lashinio model is explored at finite temperature and imaginary chemical potential with a particular emphasis on the confinement-deconfinement transition. We point out that the confined phase is characterized by a cos3{mu}{sub I}/T dependence of the chiral condensate on the imaginary chemical potential while in the deconfined phase this dependence is given by cos{mu}{sub I}/T and accompanied by a cusp structure induced by the Z(3) transition. We demonstrate that the phase structure of the model strongly depends on the choice of the Polyakov loop potential U. Furthermore, we find that by changing themore » four fermion coupling constant G{sub s}, the location of the critical end point of the deconfinement transition can be moved into the real chemical potential region. We propose a new parameter characterizing the confinement-deconfinement transition.« less

Chiral stationary phase optimized selectivity liquid chromatography: A strategy for the separation of chiral isomers.

PubMed

Hegade, Ravindra Suryakant; De Beer, Maarten; Lynen, Frederic

2017-09-15

Chiral Stationary-Phase Optimized Selectivity Liquid Chromatography (SOSLC) is proposed as a tool to optimally separate mixtures of enantiomers on a set of commercially available coupled chiral columns. This approach allows for the prediction of the separation profiles on any possible combination of the chiral stationary phases based on a limited number of preliminary analyses, followed by automated selection of the optimal column combination. Both the isocratic and gradient SOSLC approach were implemented for prediction of the retention times for a mixture of 4 chiral pairs on all possible combinations of the 5 commercial chiral columns. Predictions in isocratic and gradient mode were performed with a commercially available and with an in-house developed Microsoft visual basic algorithm, respectively. Optimal predictions in the isocratic mode required the coupling of 4 columns whereby relative deviations between the predicted and experimental retention times ranged between 2 and 7%. Gradient predictions led to the coupling of 3 chiral columns allowing baseline separation of all solutes, whereby differences between predictions and experiments ranged between 0 and 12%. The methodology is a novel tool allowing optimizing the separation of mixtures of optical isomers. Copyright © 2017 Elsevier B.V. All rights reserved.

Smeared quasidistributions in perturbation theory

NASA Astrophysics Data System (ADS)

Monahan, Christopher

2018-03-01

Quasi- and pseudodistributions provide a new approach to determining parton distribution functions from first principles' calculations of QCD. Here, I calculate the flavor nonsinglet unpolarized quasidistribution at one loop in perturbation theory, using the gradient flow to remove ultraviolet divergences. I demonstrate that, as expected, the gradient flow does not change the infrared structure of the quasidistribution at one loop and use the results to match the smeared matrix elements to those in the MS ¯ scheme. This matching calculation is required to relate numerical results obtained from nonperturbative lattice QCD computations to light-front parton distribution functions extracted from global analyses of experimental data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, B.; Molina, R.; Döring, M.

Recentmore » $$N_f=2+1$$ lattice data for meson-meson scattering in $p$-wave and isospin $I=1$ are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. We perform chiral extrapolations that postdict phase shifts extracted from experiment quite well. Additionally, the low-energy constants are compared to the ones from a recent analysis of $$N_f=2$$ lattice QCD simulations to check for the consistency of the hadronic model used here. Some inconsistencies are detected in the fits to $$N_f=2+1$$ data, in contrast to the previous analysis of $$N_f=2$$ data.« less

Flavor-Intensity Perception: Effects of Stimulus Context

PubMed Central

Marks, Lawrence E.; Shepard, Timothy G.; Burger, Kelly; Chakwin, Emily M.

2011-01-01

Stimulus context affects judgments of intensity of both gustatory and olfactory flavors, and the contextual effects are modality-specific. Does context also exert separate effects on the gustatory and olfactory components of flavor mixtures? To answer this question, in each of 4 experiments, subjects rated the perceived intensity of 16 mixtures constructed by combining 4 concentrations of the gustatory flavorant sucrose with 4 concentrations of the retronasal olfactory flavorant citral. In 1 contextual condition of each experiment, concentrations of sucrose were relatively high and those of citral low; in the other condition, the relative concentrations of sucrose and citral reversed. There were 2 main results: First, consistent with earlier findings, in 5 of the 8 conditions, the ratings were consistent with linear addition of perceived sucrose and citral; departures from additivity appeared, however, in 3 conditions where the relative concentrations of citral were high. Second, changes in context produced contrast (adaptation-like changes) in perceived intensity: The contribution to perceived intensity of a given concentration of a flavorant was smaller when the contextual concentrations of that flavorant were high rather than low. A notable exception was the absence of contextual effects on the perceived intensity of near-threshold citral. These findings suggest that the contextual effects may arise separately in the gustatory and olfactory channels, prior to the integration of perceived flavor intensity. PMID:21930139

Active chiral fluids.

PubMed

Fürthauer, S; Strempel, M; Grill, S W; Jülicher, F

2012-09-01

Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.

3D Polarized Imaging of Coronal Mass Ejections: Chirality of a CME

NASA Astrophysics Data System (ADS)

DeForest, C. E.; de Koning, C. A.; Elliott, H. A.

2017-12-01

We report on a direct polarimetric determination of the chirality of a coronal mass ejection (CME), using the physics of Thomson scattering applied to synoptic polarized images from the Solar Terrestrial Relations Observatories/COR2 coronagraph. We confirmed the determination using in situ magnetic field measurements of the same CME with the ACE spacecraft. CME chirality is related to the helicity ejected from the solar corona along with the mass and field entrained in the CME. It is also important to prediction of the space-weather-relevant Z component of the CME magnetic field. Hence, remote measurement of CME chirality is an important step toward both understanding CME physics and predicting geoeffectiveness of individual CMEs. The polarimetric properties of Thomson scattering are well known and can, in principle, be used to measure the 3D structure of imaged objects in the solar corona and inner heliosphere. However, reduction of that principle to practice has been limited by the twin difficulties of background subtraction and the signal-to-noise ratio in coronagraph data. Useful measurements of the 3D structure require relative photometry at a few percent precision level in each linear polarization component of the K corona. This corresponds to a relative photometric precision of order 10-4 in direct images of the sky before subtraction of the F corona and related signal. Our measurement was enabled by recent developments in signal processing, which enable a better separation of the photometric signal from noise in the synoptic COR2 data. We discuss the relevance of this demonstration measurement to future instrument requirements, and to the future measurements of 3D structures in CMEs and other solar wind features.