Fri·Aug 2, 2002Friday·August 2, 2002

1. 01*

   Does the QCD plasma contain propagating gluons?

   Saumen Datta🇩🇪 · Sourendu Gupta🇮🇳

   Comparison of two appropriately chosen screening masses of colour singlet operators in the pure glue QCD plasma indicates that at sufficiently high temperature it contains a weakly-interacting massive quasi-particle with the quantum numbers of the electric gluon. Still in the deconfined phase, but closer to T_c, the same mass ratio is similar to that at zero temperature, indicating that the propagating modes are more glueball-like, albeit with a lower scale for the masses. We observe a continuity between these two regimes.

   hep-lathep-phnucl-thPRD(2003)·47 citations
2. 02*

   The chemical potential in the transfer matrix and in the path integral formulation of QCD on a lattice

   F. Palumbo🇮🇹

   We define the chemical potential as the Lagrange multiplier of the baryon charge operator in the transfer matrix formalism of QCD on a lattice. Transforming the partition function into an euclidean path integral we get the Hasenfratz-Karsh action both for Wilson and Kogut-Susskind fermions. In the latter case the chemical potential in the spin-diagonal basis is half that in the flavour basis. Some open problems in the spin-diagonal basis are pointed out.

   hep-latNPB(2002)·9 citations
3. 03*

   Continuum Determination of Light Quark Masses from Quenched Lattice QCD

   Damir Becirevic🇮🇹 · Vittorio Lubicz🇮🇹 · Cecilia Tarantino🇮🇹

   We compute the strange and the average up/down quark masses in the quenched approximation of lattice QCD, by using the O(a)-improved Wilson action and operators and by implementing the non-perturbative renormalization. Our computation is performed at four values of the lattice spacing, from which we could extrapolate to the continuum limit. Our final result for the strange quark mass (in the MSbar scheme) is ms(2 GeV) = (106 +/- 2 +/- 8) MeV. For the average up/down quark mass we have ml(2 GeV) = (4.4 +/- 0.1 +/- 0.4) MeV. The ratio ms/ml = (24.3 +/- 0.2 +/- 0.6).

   hep-lathep-phPLB(2003)·24 citations
4. 04*

   Perturbative calculation of O(a) improvement coefficients

   Junpei Harada🇯🇵 · Shoji Hashimoto🇯🇵 · Andreas S. Kronfeld🇺🇸 · Tetsuya Onogi🇯🇵

   We compute several coefficients needed for O(a) improvement of currents in perturbation theory, using the Brodsky-Lepage-Mackenzie prescription for choosing an optimal scale q*. We then compare the results to non-perturbative calculations. Normalization factors of the vector and axial vector currents show good agreement, especially when allowing for small two-loop effects. On the other hand, there are large discrepancies in the coefficients of O(a) improvement terms. We suspect that they arise primarily from power corrections inherent in the non-perturbative methods.

   hep-latPRD(2003)·9 citations
5. 05*

   The transfer matrix with Kogut-Susskind fermions

   F. Palumbo🇮🇹

   A transfer matrix for gauge theories on a lattice with Kogut-Susskind fermions in the flavour basis is constructed and some difficulties in the spin-diagonal basis are pointed out.

   hep-latPRD(2002)·9 citations
6. 06*

   Study of the Finite Density State based on SU(2) Lattice QCD

   Shin Muroya🇯🇵 · Atsushi Nakamura🇯🇵 · Chiho Nonaka🇯🇵

   We report our recent numerical studies on two-color QCD with Wilson fermions. First the phase structure of the system in (kappa,mu)-plane is analyzed by measuring Polyakov line, baryon number density, gluon energy density and Polyakov line susceptibility. Then meson and baryon (di-quark) propagators are investigated. We find that the vector meson mass decreases near mu_c. This phenomena can be related to the low-mass lepton-pair enhancement observed in CERES experiment. Since our lattice is small, in order to confirm the results, we calculate both periodic and anti-periodic boundary condition cases. Preliminary calculations of color averaged, symmetric and anti-symmetric forces of qq system obtained from Polyakov line correlations, and gluon propagators are reported.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·17 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.