14184377
BROWN-RHO SCALING IN THE STRONG COUPLING LATTICE QCD
We examine the Brown-Rho scaling for meson masses in the strong coupling limit of lattice QCD with one species of staggered fermion. Analytical expression of meson masses is derived at finite temperature and chemical potential. We find that meson masses are approximately proportional to the equilibrium value of the chiral condensate, which evolves as a function of temperature and chemical potential.
119461969
Phase diagram at finite temperature and quark density in the strong coupling region of lattice QCD for colour SU(3)
We study the phase diagram of quark matter at finite temperature (T) and chemical potential (μ) in the strong coupling region of lattice QCD for colour SU(3). Baryon has effects to extend the hadron phase to a larger μ direction relative to T c at low temperatures in the strong coupling limit. With the l/g 2 corrections, T c is found to decrease rapidly as g decreases, and the shape of the phase diagram becomes closer to that expected in the real world.
2854510
Phase diagram at finite temperature and quark density in the strong coupling limit of lattice QCD for color SU(3)
We study the phase diagram of quark matter at finite temperature ($T$) and chemical potential ($\ensuremath{\mu}$) in the strong coupling limit of lattice QCD for color SU(3). We derive an analytical expression of the effective free energy as a function of $T$ and $\ensuremath{\mu}$, including baryon effects. The finite temperature effects are evaluated by integrating over the temporal link variable exactly in the Polyakov gauge with an antiperiodic boundary condition for fermions. The obtained phase diagram shows the first and the second order phase transition at low and high temperatures, respectively, and those are separated by the tricritical point in the chiral limit. Baryon has effects to reduce the effective free energy and to extend the hadron phase to a larger $\ensuremath{\mu}$ direction at low temperatures.
118755679
Composite flavor-singlet scalar in twelve-flavor QCD
We report the calculation of the flavor-singlet scalar in the SU(3) gauge theory with the degenerate twelve fermions in the fundamental representation using a HISQ-type action at a fixed $\beta$. In order to reduce the large statistical error coming from the vacuum-subtracted disconnected correlator, we employ a noise reduction method and a large number of configurations. We observe that the flavor-singlet scalar is lighter than the pion in this theory from the calculations with the fermion bilinear and gluonic operators. This peculiar feature is considered to be due to the infrared conformality of this theory, and it is a promissing signal for a walking technicolor, where a light composite Higgs boson is expected to emerge by approximate conformal dynamics.
119164995
Strong Coupling Limit/Region of Lattice QCD
We study the phase diagram of quark matter and nuclear properties based on the strong coupling expansion of lattice QCD. Both of baryon and finite coupling correction are found to have effects to extend the hadron phase to a larger μ direction relative to Tc. In a chiral RMF model with logarithmic sigma potential derived in the strong coupling limit of lattice QCD, we can avoid the chiral collapse and normal and hypernuclei properties are well described.
67846739
QCD critical point in the strong coupling lattice QCD and during black hole formation
We discuss the QCD phase diagram from two different point of view. We first investigate the phase diagram structure in the strong coupling lattice QCD with Polyakov loop effects, and show that the the chiral and Z_{N_c} deconfinement transition boundaries deviate at finite mu as suggested from large N_c arguments. Next we discuss the possibility to probe the QCD critical point during prompt black hole formation processes. The thermodynamical evolution during the black hole formation would result in quark matter formation, and the critical point in isospin asymmetric matter may be swept. (T,mu_B) region probed in heavy-ion collisions and the black hole formation processes covers most of the critical point locations predicted in recent lattice Monte-Carlo simulations and chiral effective models.
123443960
Doubly charmed baryon masses and quark wave functions in baryons
We compute the masses of the ground state baryons and their spin excited states discussing quark wave functions in baryons. Doubly charmed baryon masses are given in the expected accuracy of \ifmmode\pm\else\textpm\fi{}10 MeV.
4693182
Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts
We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodeled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From software simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1–3×10-19  Hz-1/2 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientations. These techniques include using coordinated software signal injections to estimate the network sensitivity, and tuning the analysis to maximize the sensitivity and the livetime, subject to constraints on the background.
120819057
One Gluon Exchange Contributions to Electromagnetic Mass Differences
11024901
Joint LIGO and TAMA300 search for gravitational waves from inspiralling neutron star binaries
We search for coincident gravitational wave signals from inspiralling neutron star binaries using LIGO and TAMA300 data taken during early 2003. Using a simple trigger exchange method, we perform an intercollaboration coincidence search during times when TAMA300 and only one of the LIGO sites were operational. We find no evidence of any gravitational wave signals. We place an observational upper limit on the rate of binary neutron star coalescence with component masses between 1 and 3M⊙ of 49 per year per Milky Way equivalent galaxy at a 90% confidence level. The methods developed during this search will find application in future network inspiral analyses.
123231783
Nonleptonic Hyperon Decay in the Quark Model
Nonleptonic hyperon and tr decays are discussed in the nonrelativistic quark model and the SU(6) theory, where we consider the pole diagram for quark. the four-body weak current­ current interaction J1 2 J3 1 and the meson exchange interaction_ We assume two models, and can explain the experiments for parity-violating and parity-conserving amplitudes of nonleptonic hyperon decays. In particular the L1I = 1/2 rule is derived, though the weak current-current interaction J1 2 J3 1 does not satisfy £11 = 1/2. As to the decay of tr two models predict the different ratio of r(SJ~A+K) and r(SJ~S+ll). One is consistent with experiment, the other forbids SJ~A+K.