Fri·Sep 7, 2007Friday·September 7, 2007

1. 01*

   Lattice Formulation of the N=4 D=3 Twisted Super Yang-Mills

   Alessandro D'Adda🇮🇹 · Issaku Kanamori🇯🇵 · Noboru Kawamoto🇯🇵 · Kazuhiro Nagata🇺🇸

   A lattice formulation of a three dimensional super Yang-Mills model with a twisted N=4 supersymmetry is proposed. The extended supersymmetry algebra of all eight supercharges is fully and exactly realized on the lattice with a modified "Leibniz rule". The formulation we employ here is a three dimensional extension of the manifestly gauge covariant method which was developed in our previous proposal of Dirac-Kähler twisted N=2 super Yang-Mills on a two dimensional lattice. The twisted N=4 supersymmetry algebra is geometrically realized on a three dimensional lattice with link supercharges and the use of "shifted" (anti-)commutators. A possible solution to the recent critiques on the link formulation will be discussed.

   hep-lathep-thPoS(2007)·9 citations
2. 02*

   Structure of logarithmically divergent one-loop lattice Feynman integrals

   David H. Adams🇰🇷 · Weonjong Lee🇰🇷

   For logarithmically divergent one-loop lattice Feynman integrals I(p,a), subject to mild general conditions, we prove the following expected and crucial structural result: I(p,a) = f(p)log(aM)+g(p)+h(p,M) up to terms which vanish for lattice spacing a -> 0. Here p denotes collectively the external momenta and M is a mass scale which may be chosen arbitrarily. The f(p) and h(p,M) are shown to be universal and coincide with analogous quantities in the corresponding continuum integral when the latter is regularized either by momentum cut-off or dimensional regularization. The non-universal term g(p) is shown to be a homogeneous polynomial in p of the same degree as f(p). This structure is essential for consistency between renormalized lattice and continuum formulations of QCD at one loop.

   hep-latmath-phmath.MPPRD(2008)·4 citations
3. 03*

   Supersymmetric lattice models in one and two dimensions

   Tobias Kaestner🇩🇪 · Georg Bergner🇩🇪 · Sebastian Uhlmann🇩🇪 · Andreas Wipf🇩🇪 · Christian Wozar🇩🇪

   We study and simulate N=2 supersymmetric Wess-Zumino models in one and two dimensions. For any choice of the lattice derivative, the theories can be made manifestly supersymmetric by adding appropriate improvement terms corresponding to discretizations of surface integrals. In particular, we check that fermionic and bosonic masses coincide and the unbroken Ward identities are fulfilled to high accuracy. Equally good results for the effective masses can be obtained in a model with the SLAC derivative (even without improvement terms). In two dimensions we introduce a non-standard Wilson term in such a way that the discretization errors of the kinetic terms are only of order a squared. Masses extracted from the corresponding manifestly supersymmetric model prove to approach their continuum values much quicker than those from a model containing the standard Wilson term. Again, a comparable enhancement can be achieved in a theory using the SLAC derivative.

   hep-latPoS(2007)·7 citations
4. 04*

   Spontaneous breaking of discrete symmetries in QCD on a small volume

   Biagio Lucini🇬🇧 · Agostino Patella🇮🇹 · Claudio Pica🇺🇸

   In a compact space with non-trivial cycles, for sufficiently small values of the compact dimensions, charge conjugation (C), spatial reflection (P) and time reversal (T) are spontaneously broken in QCD. The order parameter for the symmetry breaking is the trace of the Wilson line wrapping around the compact dimension, which acquires an imaginary part in the broken phase. We show that a physical signature for the symmetry breaking is a persistent baryonic current wrapping in the compact directions. The existence of such a current is derived analytically at first order in perturbation theory and confirmed in the non-perturbative regime by lattice simulations.

   hep-latAIP Conf.Proc.(2007)·3 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.