arXiv subjects

T. Yoshié

Publications and source records attributed to T. Yoshié.

115 records · Page 7Linked to original sources

arXiv1996

Finite Temperature Transitions in Lattice QCD with Wilson Quarks --- Chiral Transitions and the Influence of the Strange Quark ---

The nature of finite temperature transitions in lattice QCD with Wilson quarks is studied near the chiral limit for the cases of 2, 3, and 6 flavors of degenerate quarks ($N_F=2$, 3, and 6) and also for the case of massless up and down quarks and a light strange quark ($N_F=2+1$). Our simulations mainly performed on lattices with the temporal direction extension $N_t=4$ indicate that the finite temperature transition in the chiral limit (chiral transition) is continuous for $N_F=2$, while it is of first order for $N_F=3$ and 6. We find that the transition is of first order for the case of massless up and down quarks and the physical strange quark where we obtain a value of $m_ϕ/m_ρ$ consistent with the physical value. We also discuss the phase structure at zero temperature as well as that at finite temperatures.

hep-lat↗

arXiv1995

Hadron Masses and Decay Constants with Wilson Quarks at $β=5.85$ and 6.0

We present results of a high statistics calculation of hadron masses and meson decay constants in the quenched approximation to lattice QCD with Wilson quarks at $β=$ 5.85 and 6.0 on $24^3 \times 54$ lattices. We analyze the data paying attention in particular to the systematic errors due to the choice of fitting range and due to the contamination from excited states. We find that the systematic errors for the hadron masses with quarks lighter than the strange quark amount to 1 --- 2 times the statistical errors. When the lattice scale is fixed from the $ρ$ meson mass, the masses of the $Ω^{-}$ baryon and the $ϕ$ meson at two $β$'s agree with experiment within about one standard deviation. On the other hand, the central value of the nucleon mass at $β=6.0$ (5.85) is larger than its experimental value by about 15\% (20\%) and that of the $Δ$ mass by about 15\% (4\%): Even when the systematic errors are included, the baryon masses at $β=6.0$ do not agree with experiment. Vector meson decay constants at two values of $β$ agree well with each other and are consistent with experiment for a wide range of the quark mass, when we use current renormalization constants determined nonperturbatively by numerical simulations. The pion decay constant agrees with experiment albeit with large errors. Results for the masses of excited states of the $ρ$ meson and the nucleon are also presented.

hep-lat↗

arXiv1995

QCD Phase Transition with Strange Quark in Wilson Formalism for Fermions

The nature of QCD phase transition is studied with massless up and down quarks and a light strange quark, using the Wilson formalism for quarks on a lattice with the temporal direction extension $N_t=4$. We find that the phase transition is first order in the cases of both about 150 MeV and 400 MeV for the strange quark mass. These results together with those for three degenerate quarks suggest that QCD phase transition in nature is first order.

hep-lat↗

arXiv1995

Chiral Phase Transition in Lattice QCD with Wilson Quarks

The nature of the chiral phase transition in lattice QCD is studied for the cases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice with the temporal direction extension $N_t=4$. We find that the chiral phase transition is continuous for the case of 2 flavors, while it is of first order for 3 and 6 flavors.

hep-lat↗

arXiv1994

Nature of the finite temperature transition in QCD with strange quark

The finite temperature transition in QCD is studied using Wilson quarks for the cases of $N_F=2$, 3 and 2+1. For $N_F=2$ the transition is smooth in the chiral limit on both $\nt=4$ and 6 lattices. For $N_F=3$, clear two state signals are observed for $β\leq4.7$ on $8^2\times10 \times4$ and $12^3\times4$ lattices, which implies the transition is first order for $m_q \simm{<} 140$ MeV. For $N_F=2+1$ we study two cases of $m_s \simeq 150$ and 400 MeV with $m_u=m_d \simeq 0$. In contrast to a previous result with staggered quarks, two state signals are clearly observed for both cases, suggesting a first order QCD phase transition in the real world.

hep-lat↗

arXiv1993

Quantum chromodynamics with various number of flavors

The phase structure of QCD with various number of flavors is studied for Wilson quarks. For the case of $N_F=3$ we find that the finite temperature deconfining transition is of first order in the chiral limit on an $N_t=4$ lattice. Together with our previous results that the deconfining transition in the chiral limit is continuous for $N_F=2$ and is first order for $N_F=6$, the order of the transition is found to be consistent with a prediction of universality. The case of $SU(2)$ QCD is also studied in the strong coupling limit and the phase structure is found to be quite similar to the case of $SU(3)$: There exists a critical number of flavors $N_F^*$ and for $N_F \geq N_F^*$ the confinement is broken even in the strong coupling limit for light quarks. $N_F^*=3$ corresponding to 7 for $SU(3)$.

hep-lat↗

arXiv1993

Interface Tension in Quenched QCD

We calculate the tension $σ$ of the interface between the confined and deconfined phases by the histogram method in SU(3) lattice gauge theory for temporal extents of 4 and 6 using the recent high-statistics data by QCDPAX collaboration. The results are $σ/T_c^3 = 0.0292(22)$ and 0.0218(33) for $N_t=4$ and 6, respectively. The ratio $σ/T_c^3$ shows a scaling violation similar to that already observed for the latent heat $\latent$. However, we find that the physically interesting dimensionless combinations $(σ^{3}/\latent^2 T)^{1/2}$ and $σT/ \latent$ scale within the statistical errors.

hep-lat↗