8114935
Quenched QCD at finite temperature with overlap Fermions
We study quenched QCD just above the phase transition temperature using overlap Fermions. Exact zero modes of the overlap operator are localized. Chiral symmetry is restored, as indicated by the behavior of the chiral condensate after subtracting the effects of zero modes. The vector and pseudo-scalar screening masses are close to ideal gas values.
119431013
A precise determination of T_c in QCD from scaling
Existing lattice data on the QCD phase transition are analyzed in renormalized perturbation theory. In quenched QCD it is found that T_c scales for lattices with only 3 time slices, and that T_c/Lambda_msbar=1.15 \pm 0.05. A preliminary estimate in QCD with two flavours of dynamical quarks shows that this ratio depends on the quark mass. For realistic quark masses we estimate T_c/Lambda_msbar=0.49 \pm 0.02. We also investigate the equation of state in quenched QCD at 1-loop order in renormalised perturbation theory.
123004962
Flavour degrees of freedom and the transition temperature in QCD
We study the finite temperature transition in QCD with four flavours of dynamical quarks. Our simulation is performed on an 8×16 3 lattice for quarks of mass ma=0.01. At the coupling β c =5.15, we find long-lived metastable states, as well as an abrupt change in the entropy density, suggesting a first order phase transition. Using presently available results from corresponding calculations of the hadron masses and the chiral condensate, this gives us a transition temperature T c ≅100 MeV, which is a factor two lower than the transition temperature found in quenched QCD.
121387686
Hybrid Monte Carlo simulations of a two-dimensional gauge theory
Through a study of the dynamics of the two-dimensional U(1) pure gauge theory we find exponential slowing down in barrier penetration problems. We verify that the dynamical critical exponent in HMC can be tuned exactly to 1, and that normal and gauge fixed updates have equal cost.
122166973
The phase diagram of QCD: methods and logic of the comparison of experiments and theory
Abstract A small review of the phase diagram of QCD is presented. This is followed by a discussion of the conditions under which experimental data on the fluctuations of conserved quantities in heavy-ion collisions can be treated in the grand canonical ensemble. A robust method for detecting the presence of a nearby critical point in experiments is given. There is a short discussion of the need for non-Gaussian error analysis.
17443615
Lattice QCD for RHIC
I briefly introduce the methods by which lattice QCD predictions for RHIC are obtained. Next I deal with lattice determinations of strangeness production and event-to-event fluctuations of conserved quantities. I also present a new diagrammatic method for computing derivatives with respect to chemical potentials, and conclude with discussions of some tests of thermal perturbation theory which follow.
16643882
Caloric curve for finite nuclei in Thomas-Fermi theory
In a finite temperature Thomas-Fermi theory with realistic nuclear interactions, we construct caloric curves for finite nuclei enclosed in a sphere of about 4 to 8 times the normal nuclear volume. The specific heat capacity ${C}_{v}$ shows a peaked structure that is possibly indicative of a liquid-gas phase transition in finite nuclear systems.
118567719
A Study of Nuclear Composition of Primary Cosmic Rays above 100 TeV
The GRAPES-3 air shower array is located at Ooty (800g/cm) in southern India and consists of 256 scintillation detectors (1m each) and 16 muon detectors (35m each). In order to study the nuclear composition of primary cosmic rays around the knee energy, we investigate the relation between muon multiplicity and shower size using observations from this experiment during the period, 2000– 2001 with ∼ 10 showers having Ne > 10. These results are compared with Monte Carlo simulations (CORSIKA v6.02 with QGSJET model) to obtain the variation of the average mass number with primary energy. We have carried out detailed simulations for five types of primary nucleus (Proton, He, N, Al and Fe) for comparison with observations. We present here the details of the results.
120756008
Supercooling in viscous hydrodynamics for QCD phase transition
First order quark hadron phase transition is considered in scaling hydrodynamics including the Csernai-Kapusta model of nucleation of hadronic bubbles leading to supercooling. The effect of viscosity on the entropy production is studied in ideal as well as in viscous hydrodynamics with and without supercooling. It is found that the excess entropy produced due to supercooling depends weakly on viscosity.
118602353
Zero textures of the neutrino mass matrix from cyclic family symmetry
Abstract We present the symmetry realization of the phenomenologically viable Frampton–Glashow–Marfatia (FGM) two zero texture neutrino mass matrices in the flavor basis within the framework of the type ( I + II ) seesaw mechanism natural to SO(10) grand unification. A small Abelian cyclic symmetry group Z 3 is used to realize these textures except for class C for which the symmetry is enlarged to Z 4 . The scalar sector is restricted to the Standard Model (SM) Higgs doublet to suppress the flavor changing neutral currents. Other scalar fields used for symmetry realization are at the most two scalar triplets and, in some cases, a complex scalar singlet. Symmetry realization of one zero textures has, also, been presented.
118638637
Observation of pulsed radiation from the Crab pulsar at energies > 10**14-eV