116887618
The gluon propagator from large asymmetric lattices
The Landau-gauge gluon propagator is computed for the SU(3) gauge theory on lattices up to a size of $32^3 \times 200$. We use the standard Wilson action at $\beta = 6.0$ and compare our results with previous computations using large asymmetric and symmetric lattices. In particular, we focus on the impact of the lattice geometry and momentum cuts to achieve compatibility between data from symmetric and asymmetric lattices for a large range of momenta.
117914077
Force Gradient Integrators
We present initial results of the use of Force Gradient integ rators for lattice field theories. These promise to give significant performance improvements, espe cially for light fermions and large lattices. Our results show that this is indeed the case, indi cating a speed-up of more than a factor of two, which is expected to increase as the integration step size becomes smaller for larger lattices and smaller fermion masses.
15178500
Gauge fixing methods and Gribov copies effects in lattice QCD
We compare two Landau gauge fixing methods, aiming to find the global maximum of the gauge fixing functional. Moreover, a systematic effect of Gribov copies in the gluon and ghost propagators computed in Landau gauge is presented and discussed.
118792625
Some properties of two Nambu-Jona-Lasinio -type models with inputs from lattice QCD
IPNL, Universit´e de Lyon/Universit´e Lyon 1, CNRS/IN2P3, 4 rue E.Fermi,F-69622 Villeurbanne Cedex, FranceWe investigate the phase diagram of the so-called Polyakov–Nambu–Jona-Lasinio (PNJL) model at ﬁnite temperature and nonzero chemicalpotential. The calculations are performed in the light and strange quarksectors (u, d, s), which includes the ’t Hooft instanton induced interactionterm that breaks the axial symmetry, and the quarks are coupled to the(spatially constant) temporal background gauge ﬁeld. On one hand, a spe-cial attention is payed to the critical end point (CEP). The strength of theﬂavor-mixing interaction alters the CEP location, since when it becomesweaker the CEP moves to low temperatures and can even disappear. Onthe other hand, we also explore the connection between QCD, a nonlocalNambu–Jona-Lasinio type model and the Landau gauge gluon propaga-tor. Possible links between the quenched gluon propagator and low energyhadronic phenomenology are investigated.PACS numbers: 11.10.Wx, 11.30.Rd, 12.40.-y
118493159
Gluon screening mass at finite temperature from the Landau gauge gluon propagator in lattice QCD
We address the interpretation of the Landau gauge gluon propagator at finite temperature as a massive-type bosonic propagator. Using pure gauge SU(3) lattice simulations at a fixed lattice volume $\ensuremath{\sim}(6.5\text{ }\text{ }\mathrm{fm}{)}^{3}$, we compute the electric and magnetic form factors, extract a gluon mass from Yukawa-like fits, and study its temperature dependence. This is relevant both for the Debye screening at high temperature $T$ and for confinement at low $T$.
16286511
Infrared exponents of gluon and ghost propagators from Lattice QCD
The compatibility of the pure power law infrared solution of QCD Dyson-Schwinger equations (DSE) and lattice data for the gluon and ghost propagators in Landau gauge is discussed. For the gluon propagator, the lattice data is compatible with the DSE infrared solution with an exponent $\kappa\sim0.53$, measured using a technique that suppresses finite volume effects and allows to model these corrections to the lattice data. For the ghost propagator, the lattice data does not seem to follow the infrared DSE power law solution.
1436056
Critical coupling for dynamical chiral-symmetry breaking with an infrared finite gluon propagator
Abstract We compute the critical coupling constant for the dynamical chiral-symmetry breaking in a model of quantum chromodynamics, solving numerically the quark self-energy using infrared finite gluon propagators found as solutions of the Schwinger-Dyson equation for the gluon, and one gluon propagator determined in numerical lattice simulations. The gluon mass scale screens the force responsible for the chiral breaking, and the transition occurs only for a larger critical coupling constant than the one obtained with the perturbative propagator. The critical coupling shows a great sensibility to the gluon mass scale variation, as well as to the functional form of the gluon propagator.
119480251
Generalized Chaplygin gas model, supernovae, and cosmic topology
In this work we study to which extent the knowledge of spatial topology may place constraints on the parameters of the generalized Chaplygin gas (GCG) model for unification of dark energy and dark matter. By using both the Poincar\'e dodecahedral and binary octahedral spaces as the observable spatial topologies, we examine the current type Ia supernovae (SNe Ia) constraints on the GCG model parameters. We show that the knowledge of spatial topology does provide additional constraints on the ${A}_{s}$ parameter of the GCG model but does not lift the degeneracy of the $\ensuremath{\alpha}$ parameter.
118557980
Probing 3-3-1 Models in Diphoton Higgs Boson Decay
We investigate the Higgs boson production through gluon fusion and its decay into two photons at the LHC in the context of the minimal 3-3-1 model and its alternative version with exotic leptons. The diphoton Higgs decay channel presents an enhanced signal in this model compared to the Standard Model due to the presence of an extra singly charged vector boson and a doubly charged one. Prospects for the Higgs boson detection at 7 TeV center-of-mass energy with up to 10 fb −1 are presented. Our results suggest that a Higgs boson from these 3-3-1 models can potentially explain the small excess for mH ≤ 145 GeV observed at the LHC. Otherwise, if this excess reveals to be only a statistical fluctuation of the Standard Model backgrounds severe constraints can be put on these models.
55712077
Electroweak production of Z bosons with forward-backward jets at CMS
122619113
Infrared Finite Gluon Propagator and the Structure of Chiral Symmetry Breaking
We study the chiral symmetry breaking in QeD, using an effective potential for composite operators, with infrared finite gluon propagators that have been found by numerical calculation of the Schwinger· Dyson equations as well. as in lattice simulations. The existence of a gluon propagator that is finite at k 2 =O modifies substantially the transition between the phases with and without chiral symmetry.