HEP Lattice·hep-lat
6 papers—5 primary·1 cross-listed·reconstructed*
F. De Soto (LPSC)🇫🇷 · J. Carbonell (LPSC)🇫🇷 · C. Roiesnel (CPHT)🇫🇷 · Ph. Boucaud (LPT)🇫🇷 · J.P. Leroy (LPT)🇫🇷 · O. Pene (LPT)🇫🇷
We present the first results of a quantum field approach to nuclear models obtained by lattice techniques. Renormalization effects for fermion mass and coupling constant in case of scalar and pseudoscalar interaction lagrangian densities are discussed.
Shunsuke Takashima🇯🇵 · Ikuo Ichinose🇯🇵 · Tetsuo Matsui🇯🇵 · Kazuhiko Sakakibara🇯🇵
We study the phase structure of the 3D nonlocal compact U(1) lattice gauge theory coupled with a Higgs field by means of Monte-Carlo simulations. The nonlocal interactions among gauge variables are along the temporal direction and mimic the effect of local coupling to massless particles. We found that in contrast to the 3D local abelian Higgs model which has only one phase, the present model exhibits the confinement, Higgs, and Coulomb phases separated by three second-order transition lines emanating from a triple point. This result is quite important for studies on electron fractionalization phenomena in strongly-correlated electron systems. Implications to them are discussed.
D.J. Antonio · K.C. Bowler · P.A. Boyle · M.A. Clark · B. Joó · A.D. Kennedy · R.D. Kenway · C.M. Maynard · R.J. Tweedie · A. Yamaguchi · RBC · UKQCD Collaborations
We present results for some of the light baryon masses and their excited states in 2+1 flavour domain wall QCD. We considered several lattice spacings, with the DBW2 and Iwasaki gauge actions and different sea quark masses on a volume of and a fifth dimension of size 8. All data were generated on the QCDOC machines. Despite large residual massses and a limited number of sea quark mass values with which to perform chiral extrapolations, our results are in reasonable agreement with experiment and scale within errors. Finite size effects on most ensembles appear to be small.
Barak Bringoltz (Oxford U., Theor. Phys.)🇬🇧
We present a study of bulk thermodynamical quantities in the deconfined phase of pure lattice SU(N) gauge theories. We find that the deficit in pressure and entropy with respect to their free-gas values, for N=4,8, is remarkably close to that of SU(3). Th is suggests that understanding the strongly interacting nature of the deconfined phase, which is crucial for RHIC physics, can be done at large N. There, different analytical approaches simplify or become soluble, and one can check their predictions and point to their important ingredients.
S. Capitani🇦🇹 · K. Jansen🇩🇪 · M. Papinutto🇩🇪 · A. Shindler🇩🇪 · C. Urbach🇩🇪 · I. Wetzorke🇩🇪
We present a first Wilson twisted mass fermion calculation of the matrix element between pion states of the twist-2 operator, which is related to the the lowest moment < x > of the valence quark parton distribution function in a pion. Using Wilson twisted mass fermions in the quenched approximation we demonstrate that < x > can be computed at small pseudoscalar meson masses down to values of order 250 MeV. We investigate the scaling behaviour of this physically important quantity by applying two definitions of the critical mass and observe a scaling compatible with the expected O(a^2) behaviour in both cases. A combined continuum extrapolation allows to obtain reliable results for < x > at very small pseudoscalar meson masses, which previously could not be explored by lattice QCD simulations.
Shunsuke Takashima🇯🇵 · Ikuo Ichinose🇯🇵 · Tetsuo Matsui🇯🇵
In this paper, we study the 3D -flavor CP model (a set of CP variables) coupled with a dynamical compact U(1) gauge field by means of Monte-Carlo simulations. This model is relevant to 2D quantum spin models, and has a phase transition line which separates an ordered phase of global spin symmetry from a disordered one. From gauge theoretical point of view, the ordered phase is a Higgs phase whereas the disordered phase is a confinement phase. We are interested in the gauge dynamics just on the critical line, in particular, whether a Coulomb-like deconfinement phase is realized there. This problem is quite important to clarify low-energy excitations in certain class of quantum spin models. If the gauge dynamics is in the deconfinement phase there, spinons, which transform in the fundamental representation of the SU() symmetry, appear as low-energy excitations. By Monte-Carlo simulations, we found that the "phase structure" on the {\em criticality} strongly depends on the value of . For small , the confinement phase is realized, whereas the deconfinement phase appears for sufficient large . This result strongly suggests that compact QED is in a deconfinement phase for sufficiently large number of flavors of massless fermions.
* 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.