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S. Hashimoto

Publications and source records attributed to S. Hashimoto.

244 records · Page 14Linked to original sources
arXiv1997

Lattice QCD Calculation of the Kaon B-parameter with the Wilson Quark Action

The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the Δs=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables us to construct the weak four-quark operators exhibiting good chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.

hep-lat↗
arXiv1996

Topics in Light Hadron Mass Spectrum in Quenched QCD

Several topics concerning the light hadron spectrum are discussed. Flavor symmetry breaking effects and the problem of quenched chiral logarithm are examined with pion mass data for the Kogut-Susskind quark action, and light meson decay constants for the Wilson action calculated with non-perturbative renormalization constants are discussed. Results for quark masses are also given both for the Kogut-Susskind and Wilson actions.

hep-lat↗
arXiv1996

Continuum Limit of the Heavy-Light Decay Constant with the Quenched Wilson Quark Action

We explore the problems in calculating the decay constant for heavy-light mesons using the quenched Wilson quark action for both heavy and light quarks. We find that the continuum limit of the decay constant is reasonably converged among different prescriptions after the continuum limit is taken. A number of technical problems associated with prescriptions are also addressed.

hep-lat↗
arXiv1996

Toward the Continuum Limit of $B_K$ with the Quenched Kogut-Susskind Quark Action

We present new results of our ongoing project toward a precision determination of the kaon $B$ parameter with the Kogut-Susskind quark action in quenched QCD. New results taken at $β$=6.4 and $β=5.7$ suggest that an apparently linear $a$ dependence of $B_K$ previously observed for $β=5.85-6.2$ arises from a change of curvature from convex to concave as the lattice spacing is reduced. Fitting data for $β\geq 5.93$ with an $O(a^2)$ form yields $B_K$(NDR,2 GeV)=0.587(7)(17) in the continuum limit. We also describe a finite-size study of $B_K$ at $β=$ 6.0 and 6.4, and a reanalysis of the theoretical argument for $O(a^2)$ behavior.

hep-lat↗
arXiv1995

Lattice Heavy Quark Effective Theory and the Isgur-Wise function

We compute the Isgur-Wise function using heavy quark effective theory formulated on the lattice. The non-relativistic kinetic energy term of the heavy quark is included to the action as well as terms remaining in the infinite quark mass limit. The classical velocity of the heavy quark is renormalized on the lattice and we determine the renormalized velocity non-perturbatively using the energy-momentum dispersion relation. The slope parameter of the Isgur-Wise function at zero recoil is obtained at $β=6.0$ on a $24^3\times 48$ lattice for three values of $m_{Q}$.

hep-lat↗
arXiv1994

Charmonium spectroscopy with heavy Kogut-Susskind quarks

Charmonium spectroscopy with Kogut-Susskind valence quarks are carried out for quenched QCD at $β=6.0$ and for two-flavor full QCD at $β=5.7$. Results for 1P--1S mass splitting and estimates of $α^{(5)}_{\overline{MS}}(m_Z)$ are reported. Problems associated with flavor breaking effects and finite size effects of $1P$ states are discussed.

hep-lat↗
arXiv1994

Manifestation of Sea Quark Effects in the Strong Coupling Constant in Lattice QCD

We demonstrate that sea quark effects of a magnitude expected from renormalization group considerations are clearly visible in the strong coupling constant measured in current full QCD simulations. Building on this result an estimate of $α_{\overline{MS}}^{(5)}(M_Z)$ is made employing the charmonium $1S-1P$ mass splitting calculated on full QCD configurations generated with two flavors of dynamical Kogut-Susskind quarks to fix the scale.

hep-lat↗
arXiv1993

Sea Quark Effects on the Strong Coupling Constant

We present results showing that the strong coupling constant measured in two-flavor full QCD with dynamical Kogut-Susskind quarks at $β=5.7$ exhibit a 15\% increase due to sea quarks over that for quenched QCD at the scale $μ\approx 7$GeV . (talk at lattice93)

hep-lat↗
arXiv1992

Dynamical CP Violation in Composite Higgs Models

The dynamical origin of the CP violation in electroweak theory is investigated in composite Higgs models. The mechanism of the spontaneous CP violation proposed in other context by Dashen is adopted to construct simple models of the dynamical CP violation. Within the models the size of the neutron electric dipole moment is estimated and the constraint on the $\varepsilon$-parameter in K-meson decays is discussed.

hep-ph↗