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.
120122235
Nonleptonic Decays of Charmed Baryons in the Quark Model
120461364
Electromagnetic Mass Differences of Charmed Particles
120819057
One Gluon Exchange Contributions to Electromagnetic Mass Differences
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.
123768278
The Lowest (1/2+ and 0-) Hadron Masses and the Behavior of the Constituent Quarks
Masses of the lowest lying hadrons and the behavior of constituent quarks are discussed on the analysis of their electromagnetic properties, based on QCD. We find that light quarks (u and d) in the hadrons move with the velocity ::::O.Sc; s quark, with :$0.7c; c quark, with nearly 0.3c. Then we know that the confinement force, no matter what kind of confinement one prefers, does not mainly contribute to the hadron masses. It is also conjectured that Jv,-eJilu-d J;=;[v1,-,11[/Jc-sJ;=;Jv,-rJ/ lt-bl and m,:-::23 GeV on the assumption of the ex­ istence of the next layer. Masses of quarks, of which a hadron is built, are assumed arbitrarily to be from zero to infinity on the argument of various hadronic processes, but the constituent quark masses seem to be mu:-::330 and ms:-::510 (in units of MeV) in the inter­ mediate region at which the magnetic moments and the spectroscopy of hadrons are discussed.ll Can 7r have a mass of an order of one hundred MeV, when it is considered that it is a bound state of such quarks? How do the quarks behave in 7r or other hadrons? This note will con­ tribute to the analysis of the lowest lying hadron masses on the basis of the analysis of the electromagnetic properties by follow­ ing the previous discussions. 2>
13509849
Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy.
TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of h approximately 5x10(-21)/sqrt[Hz], a signal-to-noise ratio of 30 is expected for gravitational waves generated by a coalescence of 1.4M-1.4M binary neutron stars at 10 kpc distance. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.
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.
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.
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.
53495167
Light composite scalar in eight-flavor QCD on the lattice
In search for a composite Higgs boson (techni-dilaton) in the walking technicolor, we present our preliminary results on the first observation of a light flavor-singlet scalar in a candidate theory for the walking technicolor, the Nf=8 QCD, which was found in our previous paper to have spontaneous chiral symmetry breaking together with remnants of the conformality. Based on simulations with the HISQ-type action on several lattice sizes with various fermion masses, we find evidence of a flavor-singlet scalar meson with mass comparable to that of the Nambu-Goldstone pion in both the small fermion-mass region, where chiral perturbation theory works, and the intermediate fermion-mass region where the hyperscaling relation holds. We further discuss its chiral limit extrapolation in comparison with other states studied in our previous paper: the scalar has a mass much smaller than that of the vector meson, which is compared to the Nambu-Goldstone pion having a vanishing mass in that limit.