The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
S Aoki - One of the best experts on this subject based on the ideXlab platform.
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Vector and axial Currents in wilson chiral perturbation theory
Physical Review D, 2009Co-Authors: S Aoki, Oliver Bar, Stephen R SharpeAbstract:We reconsider the construction of the Vector and axial-Vector Currents in Wilson Chiral Perturbation Theory, the low-energy effective theory for lattice QCD with Wilson fermions. We discuss in detail the finite renormalization of the Currents that has to be taken into account in order to properly match the Currents. We explicitly show that imposing the chiral Ward identities on the Currents does, in general, affect the axial-Vector current at O(a). As an application of our results we compute the pion decay constant to one loop in the two-flavor theory. Our result differs from previously published ones.
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s parameter and pseudo nambu goldstone boson mass from lattice qcd
Physical Review Letters, 2008Co-Authors: Eigo Shintani, S Aoki, Hidenori Fukaya, S Hashimoto, T Kaneko, Hideo Matsufuru, T Onogi, N YamadaAbstract:We present a lattice calculation of L{sub 10}, one of the low-energy constants in chiral perturbation theory, and the charged-neutral pion squared-mass splitting, using dynamical overlap fermion. The exact chiral symmetry of the overlap fermion allows us to reliably extract these quantities from the difference of the vacuum polarization functions for Vector and axial-Vector Currents. In the context of the technicolor models, these two quantities are read as the S parameter and the pseudo Nambu-Goldstone boson mass, respectively, and play an important role in discriminating the models from others. This calculation can serve as a feasibility study of the lattice techniques for more general technicolor gauge theories.
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perturbative determination of mass dependent renormalization and improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
Nuclear Physics, 2005Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:Abstract We determine the mass-dependent renormalization as well as improvement coefficients for the heavy–light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks through the standard matching procedure. The calculation is carried out perturbatively at the one-loop level to remove the systematic error of O ( α s ( a m Q ) n a p ) as well as O ( α s ( a m Q ) n ) ( n ⩾ 0 ), where p is a typical momentum scale in the heavy–light system. We point out that renormalization and improvement coefficients of the heavy–light Vector current agree with those of the axial-Vector current, thanks to the exact chiral symmetry for the light quark. The results obtained with three different gauge actions, plaquette, Iwasaki and DBW2, are presented as a function of heavy quark mass and domain-wall height.
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Nonperturbative renormalization of meson decay constants in quenched QCD for a renormalization group improved gauge action
Physical Review D, 2004Co-Authors: K Ide, S Aoki, S Hashimoto, M Fukugita, N Ishizuka, Y Iwasaki, R. Burkhalter, Ken-ichi Ishikawa, T. Ishikawa, K KanayaAbstract:Renormalization constants (Z-factors ) of Vector and axial-Vector Currents are determined nonperturbatively in quenched QCD for a renormalization group improved gauge action and a tadpole-improved clover quark action using the Schroedinger functional method. Nonperturbative values of Z-factors turn out to be smaller than 1-loop perturbative values by O(15%) at a lattice spacing of a{sup -1}{approx_equal} 1 GeV. The pseudoscalar and Vector meson decay constants calculated with the nonperturbative Z-factors show a much better scaling behavior compared to previous results obtained with tadpole-improved one-loop Z-factors. In particular, the nonperturbative Z-factors normalized at infinite physical volume show that the scaling violations of the decay constants are within about 10% up to the lattice spacing a{sup -1}{approx}1 GeV. The continuum estimates obtained from data in the range a{sup -1}{approx} 1-2 GeV agree with those determined from finer lattices (a{sup -1}{approx}2-4 GeV) with the standard action.
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one loop determination of mass dependent o a improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
arXiv: High Energy Physics - Lattice, 2004Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:We present the one-loop results of the mass dependent $O(a)$ improvement coefficients for the heavy-light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks. The calculations are performed with the plaquette, Iwasaki and DBW2 gauge actions. The heavy quark mass and domain-wall height dependence is investigated. We point out that the exact chiral symmetry held by the lattice light quark action leads to an exact relation between the improvement coefficients for the Vector and axial-Vector Currents without regard to the lattice heavy quark action.
Yoshinobu Kuramashi - One of the best experts on this subject based on the ideXlab platform.
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perturbative determination of mass dependent renormalization and improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
Nuclear Physics, 2005Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:Abstract We determine the mass-dependent renormalization as well as improvement coefficients for the heavy–light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks through the standard matching procedure. The calculation is carried out perturbatively at the one-loop level to remove the systematic error of O ( α s ( a m Q ) n a p ) as well as O ( α s ( a m Q ) n ) ( n ⩾ 0 ), where p is a typical momentum scale in the heavy–light system. We point out that renormalization and improvement coefficients of the heavy–light Vector current agree with those of the axial-Vector current, thanks to the exact chiral symmetry for the light quark. The results obtained with three different gauge actions, plaquette, Iwasaki and DBW2, are presented as a function of heavy quark mass and domain-wall height.
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one loop determination of mass dependent o a improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
arXiv: High Energy Physics - Lattice, 2004Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:We present the one-loop results of the mass dependent $O(a)$ improvement coefficients for the heavy-light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks. The calculations are performed with the plaquette, Iwasaki and DBW2 gauge actions. The heavy quark mass and domain-wall height dependence is investigated. We point out that the exact chiral symmetry held by the lattice light quark action leads to an exact relation between the improvement coefficients for the Vector and axial-Vector Currents without regard to the lattice heavy quark action.
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perturbative determination of mass dependent o a improvement coefficients for the Vector and axial Vector Currents with a relativistic heavy quark action
Nuclear Physics, 2004Co-Authors: S Aoki, Yasuhisa Kayaba, Yoshinobu KuramashiAbstract:Abstract We carry out a perturbative determination of mass dependent renormalization factors and O ( a ) improvement coefficients for the Vector and axial Vector Currents with a relativistic heavy quark action, which we have designed to control m Q a errors by extending the on-shell O ( a ) improvement program to the case of m Q ⪢ Λ QCD with m Q the heavy quark mass. We discuss what kind of improvement operators are required for the heavy–heavy and the heavy–light cases under the condition that the Euclidean rotational symmetry is not retained anymore because of the m Q a corrections. Our calculation is performed employing the ordinary perturbation theory with the fictitious gluon mass as an infrared regulator. We show that all the improvement coefficients are determined free from infrared divergences. Results of the renormalization factors and the improvement coefficients are presented as a function of m Q a for various improved gauge actions as well as the plaquette action.
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Perturbative renormalization factors of bilinear operators for massive Wilson quarks on the lattice
Physical Review D, 1998Co-Authors: Yoshinobu KuramashiAbstract:Renormalization factors for local Vector and axial Vector Currents for the Wilson quark action are perturbatively calculated to one loop order including finite quark masses from the ratio of the on-shell quark matrix elements in the Feynman gauge defined on the lattice and in the continuum. For large quark masses of order unity in lattice units, we find that finite quark mass effects are quite large: one-loop coefficients of the renormalization factors differ by 100% compared to those in the massless limit.
M I Polikarpov - One of the best experts on this subject based on the ideXlab platform.
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magnetic field induced insulator conductor transition in su 2 quenched lattice gauge theory
Physical Review Letters, 2010Co-Authors: P V Buividovich, M N Chernodub, D E Kharzeev, Tigran Kalaydzhyan, E V Luschevskaya, M I PolikarpovAbstract:We study the correlator of two Vector Currents in quenched SU(2) lattice gauge theory with a chirally invariant lattice Dirac operator with a constant external magnetic field. It is found that in the confinement phase the correlator of the components of the current parallel to the magnetic field decays much slower than in the absence of a magnetic field, while for other components the correlation length slightly decreases. We apply the maximal entropy method to extract the corresponding spectral function. In the limit of zero frequency this spectral function yields the electric conductivity of quenched theory. We find that in the confinement phase the external magnetic field induces nonzero electric conductivity along the direction of the field, transforming the system from an insulator into an anisotropic conductor. In the deconfinement phase the conductivity does not exhibit any sizable dependence on the magnetic field.
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Magnetic-Field-Induced insulator-conductor transition in SU(2) quenched lattice gauge theory
Physical Review Letters, 2010Co-Authors: P V Buividovich, M N Chernodub, D E Kharzeev, Tigran Kalaydzhyan, E V Luschevskaya, M I PolikarpovAbstract:We study the correlator of two Vector Currents in quenched SU(2) lattice gauge theory with chirally invariant lattice Dirac operator with constant external magnetic field. It is found that in the confinement phase the correlator of the components of the current parallel to the magnetic field decays much slower than in the absence of magnetic field, while for other components the correlation length slightly decreases. We apply the Maximal Entropy Method to extract the spectral function which corresponds to this correlator. The value of this spectral function in the limit of zero frequency yields, by virtue of the Green-Kubo relations, the electric conductivity of quenched lattice gauge theory. We find that in the confinement phase the external magnetic field induces nonzero electric conductivity along the direction of the field, transforming the system from an insulator into an anisotropic conductor. In the deconfinement phase the conductivity does not exhibit any sizable dependence on the magnetic field.
N Yamada - One of the best experts on this subject based on the ideXlab platform.
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s parameter and pseudo nambu goldstone boson mass from lattice qcd
Physical Review Letters, 2008Co-Authors: Eigo Shintani, S Aoki, Hidenori Fukaya, S Hashimoto, T Kaneko, Hideo Matsufuru, T Onogi, N YamadaAbstract:We present a lattice calculation of L{sub 10}, one of the low-energy constants in chiral perturbation theory, and the charged-neutral pion squared-mass splitting, using dynamical overlap fermion. The exact chiral symmetry of the overlap fermion allows us to reliably extract these quantities from the difference of the vacuum polarization functions for Vector and axial-Vector Currents. In the context of the technicolor models, these two quantities are read as the S parameter and the pseudo Nambu-Goldstone boson mass, respectively, and play an important role in discriminating the models from others. This calculation can serve as a feasibility study of the lattice techniques for more general technicolor gauge theories.
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perturbative determination of mass dependent renormalization and improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
Nuclear Physics, 2005Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:Abstract We determine the mass-dependent renormalization as well as improvement coefficients for the heavy–light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks through the standard matching procedure. The calculation is carried out perturbatively at the one-loop level to remove the systematic error of O ( α s ( a m Q ) n a p ) as well as O ( α s ( a m Q ) n ) ( n ⩾ 0 ), where p is a typical momentum scale in the heavy–light system. We point out that renormalization and improvement coefficients of the heavy–light Vector current agree with those of the axial-Vector current, thanks to the exact chiral symmetry for the light quark. The results obtained with three different gauge actions, plaquette, Iwasaki and DBW2, are presented as a function of heavy quark mass and domain-wall height.
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one loop determination of mass dependent o a improvement coefficients for the heavy light Vector and axial Vector Currents with relativistic heavy and domain wall light quarks
arXiv: High Energy Physics - Lattice, 2004Co-Authors: N Yamada, S Aoki, Yoshinobu KuramashiAbstract:We present the one-loop results of the mass dependent $O(a)$ improvement coefficients for the heavy-light Vector and axial-Vector Currents consisting of the relativistic heavy and the domain-wall light quarks. The calculations are performed with the plaquette, Iwasaki and DBW2 gauge actions. The heavy quark mass and domain-wall height dependence is investigated. We point out that the exact chiral symmetry held by the lattice light quark action leads to an exact relation between the improvement coefficients for the Vector and axial-Vector Currents without regard to the lattice heavy quark action.
S Nicotri - One of the best experts on this subject based on the ideXlab platform.
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anomalous av v vertex function in the soft wall holographic model of qcd
Physical Review D, 2012Co-Authors: P Colangelo, F De Fazio, Juan Jose Sanzcillero, Floriana Giannuzzi, S NicotriAbstract:We consider the vertex function of two Vector and one axial-Vector Currents using the soft-wall holographic model of QCD with the Chern-Simons term. Two structure functions wL and wT describe such a vertex in the special case in which one of the two Vector Currents corresponds to an on-shell soft photon. We briey review the QCD results for these functions, obtained from triangular loop diagrams with quarks having massmq = 0 ormq6 0, we computewL andwT in the soft-wall model and compare the outcome to the QCD ndings. We also calculate and discuss the two-point V V AA correlation function, together with a few low-energy constants, which turn out to be close to the QCD results.
