17004831
Taylor expansions in chemical potential
Properties of QCD at finite chemical potential (µ) are extracted using Taylor series expansions. The continuum limits of lattice results are presented. The result of expanding the free energy density, i.e., the pressure, to 6th order in the expansion is shown. The Taylor coefficients of the chiral condensate are also shown. Relations between various Taylor coefficients are demonstrated. All this information is utilised to remove various lattice artifacts from the determination of the Wroblewski parameter in strangeness production.
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.
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.
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.
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.
123622657
Many-particle density of states in a finite-dimensional vector space
Abstract We demonstrate that the statistical mechanics methods for obtaining the density of states, when applied to a finite dimensional vector space, leads to a Gaussian distribution in the lowest order. Successive approximations lead naturally to the Gram-Charlier series.
122963652
Intrinsic density and energy dependence: Exchange effects in alpha-nucleus scattering
The exchange effect for the alpha-nucleus potential has been computed by folding in the density matrices with a finite range effective interaction. The ''effective'' exchange interaction is both density and energy dependent. The potential agrees closely with phenomenology.
118808591
A soluble statistical model for nuclear fragmentation
The statistical model of Chase and Mekjian, which offers an analytic solution for the canonical ensemble of non-interacting fragments, is investigated for it's thermodynamic behavior. Various properties of the model, which exhibits a first-order phase transition, are studied. The effects of finite particle number are investigated. Three extensions of the model are considered, excluded volume, Coulomb effects and inclusion of isospin degrees of freedom. A formulation of a microcanonical version of the model is also presented.
109607695
Vacuum system design for twenty-cell PWT Linac structure
This paper describes the vacuum system design for a 20-cell Plane Wave Transformer (PWT) type LINear ACcelerator (LINAC) structure to obtain a vacuum better than 5×10−8 mbar everywhere inside the linac structure. Specific material out-gassing rate for a 20-cell linac is determined on the basis of vacuum achieved in a similar type of 8-cell linac structure, which is smaller in length, and presently under operation in the Compact Ultrafast TEra-hertz Free Electron Laser (CUTE-FEL) beam transport line at RRCAT.
119964333
Magnetic and quadrupole moments of the W boson
The validity of the external-field treatment for the electromagnetic scattering of a W boson in the Weinberg model is examined, and calculation of the magnetic and quadrupole moments of the W boson is carried out in the renormalizable gauge instead of the unitary gauge used by earlier authors. Our results agree with those of Bardeen, Gastmans, and Lautrup in the static approximation, and thus gauge independence of these results is demonstrated. (AIP)