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We present a study of the topological susceptibility in lattice QCD with two degenerate flavors of dynamical quarks. The topological charge is measured on gauge configurations generated with a renormalization group improved gauge action and…

Chiral perturbation theory predicts that in quantum chromodynamics (QCD), light dynamical quarks suppress the gauge-field topological susceptibility of the vacuum. The degree of suppression depends on quark multiplicity and masses. It…

We investigate the QCD topological susceptibility $\chi_t$ by using the nonlocal chiral quark model (NL$\chi$QM). This model is based on the liquid instanton QCD-vacuum configuration in which $\mathrm{SU}(3)$ flavor symmetry is explicitly…

High Energy Physics - Phenomenology · Physics 2017-08-02 Seung-il Nam , Chung-Wen Kao

We present a precise computation of the topological susceptibility $\chi_{_\mathrm{YM}}$ of SU$(N)$ Yang-Mills theory in the large $N$ limit. The computation is done on the lattice, using high-statistics Monte Carlo simulations with $N=3,…

High Energy Physics - Lattice · Physics 2016-10-28 Marco Cè , Miguel García Vera , Leonardo Giusti , Stefan Schaefer

We measure the topological charge and its fluctuation for the gauge configurations generated by the RBC and UKQCD Collaborations using 2+1 flavors of domain-wall fermions on the 16^3 x 32 lattice (L \simeq 2 fm) with length 16 in the fifth…

High Energy Physics - Lattice · Physics 2019-08-13 Ting-Wai Chiu , Tung-Han Hsieh , Po-Kai Tseng

We perform hybrid Monte-Carlo (HMC) simulation of lattice QCD with $N_f=2+1+1$ domain-wall quarks at the physical point, on the $64^3 \times (64,20,16,12,10,8,6)$ lattices, each with three lattice spacings. The lattice spacings and the bare…

High Energy Physics - Lattice · Physics 2022-10-13 Yu-Chih Chen , Ting-Wai Chiu , Tung-Han Hsieh

We report first calculations of the topological susceptibility measured using the field theoretic method on SU(3) gauge configurations produced by the UKQCD collaboration with two flavours of dynamical, improved, Wilson fermions. Using…

High Energy Physics - Lattice · Physics 2015-06-25 A. Hart , M. Teper

Chiral perturbation theory predicts that in quantum chromodymamics light dynamical quarks suppress the topological (instanton) susceptibility. We investigate this suppression through direct numerical simulation using the Asqtad improved…

High Energy Physics - Lattice · Physics 2008-11-26 C. Bernard , T. DeGrand , C. DeTar , Steven Gottlieb , E. Gregory , A. Hart , A. Hasenfratz , Urs Heller , J. Hetrick , J. Osborn , R. Sugar , D. Toussaint

We consider the simulation of finite temperature QCD with two flavors of dynamical overlap fermions in order to study the suppression of the axial U(1) symmetry breaking at the chiral phase transition point. As a preliminary study, pure…

High Energy Physics - Lattice · Physics 2012-04-23 Guido Cossu , Sinya Aoki , Shoji Hashimoto , Takashi Kaneko , Hideo Matsufuru , Jun-ichi Noaki , Eigo Shintani

We calculate the topological susceptibility of the Yang-Mills vacuum using the field correlator method. Our estimate for the SU(3) gauge group, \chi^{1/4} = 196(7) MeV, is in a very good agreement with the results of recent numerical…

High Energy Physics - Phenomenology · Physics 2011-07-19 M. N. Chernodub , I. E. Kozlov

We compute the topological susceptibility $\chi_t$ of lattice QCD with $2+1$ dynamical quark flavors described by the M\"obius domain wall fermion. Violation of chiral symmetry as measured by the residual mass is kept at $\sim$1 MeV or…

High Energy Physics - Lattice · Physics 2019-12-06 S. Aoki , G. Cossu , H. Fukaya , S. Hashimoto , T. Kaneko

As a test of the chiral properties of the improved Asqtad (staggered fermion) action, we have been measuring the topological susceptibility as a function of quark masses for 2 + 1 dynamical flavors. We report preliminary results, which show…

In a previous paper \cite{Jahn:2018dke} we presented a methodology for computing the topological susceptibility of QCD at temperatures where it is small and standard methods fail. Here we improve on this methodology by removing two barriers…

High Energy Physics - Lattice · Physics 2020-02-05 P. Thomas Jahn , Guy D. Moore , Daniel Robaina

We determine the topological susceptibility $ \chi_t $ in the trivial topological sector generated by lattice simulations of two-flavor QCD with overlap Dirac fermion, on a $16^3 \times 32$ lattice with lattice spacing $\sim$ 0.12 fm, at…

High Energy Physics - Lattice · Physics 2011-02-16 T. W. Chiu , S. Aoki , H. Fukaya , S. Hashimoto , T. H. Hsieh , T. Kaneko , H. Matsufuru , J. Noaki , K. Ogawa , T. Onogi , N. Yamada

We present the results of a computation of the topological susceptibility in the SU(3) Yang--Mills theory performed by employing the expression of the topological charge density operator suggested by Neuberger's fermions. In the continuum…

High Energy Physics - Lattice · Physics 2009-11-10 Luigi Del Debbio , Leonardo Giusti , Claudio Pica

The topological susceptibility is calculated within the Hamiltonian approach to Yang-Mills theory in Coulomb gauge, using the vacuum wave functional previously determined by a variational solution of the Yang-Mills Schroedinger equation.…

High Energy Physics - Theory · Physics 2008-11-26 Davide R. Campagnari , Hugo Reinhardt

We compute the topological susceptibility chi_t in SU(3) lattice gauge theory using fermionic methods based on the Atiyah-Singer index theorem. Near the phase transition we find a smooth crossover behavior for chi_t with values decreasing…

High Energy Physics - Lattice · Physics 2009-11-07 Christof Gattringer , Roland Hoffmann , Stefan Schaefer

Using Monte Carlo simulations with overrelaxation, we have equilibrated lattices up to $\beta=2.928$, size $60^4$, for pure SU(2) lattice gauge theory with the Wilson action. We calculate topological charges with the standard cooling method…

High Energy Physics - Lattice · Physics 2019-03-06 Bernd A. Berg , David A. Clarke

We measure the topological susceptibility of quenched QCD on the lattice at two high temperatures. For this, we define topology with the help of gradient flow and mitigate the statistical problem of topology at high temperatures using a…

High Energy Physics - Lattice · Physics 2018-11-01 P. Thomas Jahn , Guy D. Moore , Daniel Robaina

The 2d O(3) model is widely used as a toy model for ferromagnetism and for Quantum Chromodynamics. With the latter it shares --- among other basic aspects --- the property that the continuum functional integral splits into topological…

High Energy Physics - Lattice · Physics 2018-12-12 Wolfgang Bietenholz , Philippe de Forcrand , Urs Gerber , Héctor Mejía-Díaz , Ilya O. Sandoval