Hasil untuk "hep-lat"

W. Bietenholz

Researchers working in lattice field theory constitute an established community since the early 1990s, and around the same time the online open-access e-print repository arXiv was created. The fact that this field has a specific arXiv section, hep-lat, provides a unique opportunity for a statistical study of its evolution over the last three decades. We present data for the number of entries, $E$, published papers, $P$, and citations, $C$, in total and separated by nations. We compare them to 6 other arXiv sections, and to socio-economic indices of the nations involved, namely the Gross Domestic Product (GDP) and the Education Index (EI). We present rankings, which are based either on the Hirsch Index $H$, or on the linear combination $\Sigma = E + P + 0.05 C$. We consider both extensive and intensive national statistics, i.e. absolute and relative to the population or to the GDP.

M. Chu

K. Szabó

I review some of the most important recent results from finite temperature lattice QCD based on the contributions of the Budapest-Wuppertal collaboration. In particular I’ll cover the equation of state [1], the role of the charm quark, and the fluctuation observables also measured in heavy ion physics [2]. I will comment on the the reliability of the hadron resonance gas model for low temperatures and the hard thermal loop approximation at high temperatures [3]. References [1] S. Borsanyi, Z. Fodor, C. Hoelbling, S. D. Katz, S. Krieg and K. K. Szabo, Phys.Lett.B 730 (2014) 99 [arXiv:1309.5258 [hep-lat]]. [2] S. Borsanyi, Z. Fodor, S. D. Katz, S. Krieg, C. Ratti and K. K. Szabo, arXiv:1403.4576 [heplat]. [3] N. Haque, A. Bandyopadhyay, J. O. Andersen, M. G. Mustafa, M. Strickland and N. Su, JHEP 1405 (2014) 027 [arXiv:1402.6907 [hep-ph]].

T. DeGrand, Y. Shamir, B. Svetitsky

As a follow up to the previous talk about the beta function of SU(3) gauge theory with Nf=2 symmetric representation (clover) fermions [arXiv:0809.2885 [hep-lat]], we describe our explorations of the beta-kappa plane, away from the massless limit. Our simulations are mostly done on lattices of length L=8 and 12. We observe a phase transition from a strong coupling confined phase to a deconfined, chirally restored phase. The line of transitions avoids (so far) the location of the infrared fixed point discussed in the last talk.

S. Beane, K. Orginos, M. Savage

Abstract We determine the strong-isospin violating component of the neutron–proton mass difference from fully-dynamical lattice QCD and partially-quenched QCD calculations of the nucleon mass, constrained by partially-quenched chiral perturbation theory at one-loop level. The lattice calculations were performed with domain-wall valence quarks on MILC lattices with rooted staggered sea-quarks at a lattice spacing of b = 0.125  fm , lattice spatial size of L = 2.5  fm and pion masses ranging from m π ∼ 290  MeV to ∼ 350  MeV . At the physical value of the pion mass, we predict M n − M p | d − u = 2.26 ± 0.57 ± 0.42 ± 0.10  MeV where the first error is statistical, the second error is due to the uncertainty in the ratio of light-quark masses, η = m u / m d , determined by MILC [C. Aubin, et al., MILC Collaboration, Phys. Rev. D 70 (2004) 114501, hep-lat/0407028], and the third error is an estimate of the systematic due to chiral extrapolation.

D. Kaplan

A method is proposed for latticizing a class of supersymmetric gauge theories, including N=4 super Yang-Mills. The technique is inspired by recent work on ``deconstruction''. Part of the target theory's supersymmetry is realized exactly on the lattice, reducing or eliminating the need for fine tuning. (Talk based on the paper"Supersymmetry on a Spatial Lattice", hep-lat/0206019, by D.B.K., Emmanuel Katz and Mithat Unsal).