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Related papers: Conformal phase transition in QCD like theories an…

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We investigate the topological susceptibility of the QCD vacuum with two flavours of dynamical staggered fermions on the lattice both at zero and finite temperature. At zero temperature we study the dependence of the signal on the fermion…

High Energy Physics - Lattice · Physics 2015-06-25 B. Alles , M. D'Elia , A. Di Giacomo

We investigate QCD with a large number of massless flavors with the aid of renormalization group flow equations. We determine the critical number of flavors separating the phases with and without chiral symmetry breaking in SU(Nc) gauge…

High Energy Physics - Phenomenology · Physics 2009-01-07 Holger Gies , Joerg Jaeckel

When the number of massless fermions exceeds a critical value $N_f^*$, QCD enters the conformal window and becomes chirally symmetric already in the vacuum. Determining $N_f^*$ from lattice simulations is challenging, since calculations are…

High Energy Physics - Lattice · Physics 2026-03-23 Jan Philipp Klinger , Reinhold Kaiser , Owe Philipsen , Jonas Schaible

With a sufficiently high number of fundamental fermionic flavours present, Yang-Mills theory develops an infrared fixed point and becomes (quasi-)conformal in nature. The range of flavour numbers for which this occurs defines the conformal…

High Energy Physics - Lattice · Physics 2010-11-05 Albert Deuzeman , Maria Paola Lombardo , Elisabetta Pallante

We investigate the chiral phase transition at finite temperature (T) in colour SU(Nc=3) Quantum Chromodynamics (QCD) with six species of fermions (Nf=6) in the fundamental representation by using lattice QCD with improved staggered…

High Energy Physics - Lattice · Physics 2012-03-30 Kohtaroh Miura , Maria Paola Lombardo , Elisabetta Pallante

We study the thermal phase transition in colour SU(3) Quantum Chromodynamics (QCD) with a variable number of fermions in the fundamental representation by using lattice Monte-Carlo simulations. We collect the (pseudo) critical couplings for…

High Energy Physics - Lattice · Physics 2013-03-19 Kohtaroh Miura , Maria Paola Lombardo

I give an elementary introduction to the study of gauge theories coupled to fermions with many degrees of freedom. Besides their intrinsic interest, these theories are candidates for nonperturbative extensions of the Higgs sector of the…

High Energy Physics - Lattice · Physics 2015-05-20 Thomas DeGrand

We extend the phase diagram of SU(N) gauge-fermion theories as function of number of flavours and colours to the region in which asymptotic freedom is lost. We argue, using large $N_f$ results, for the existence of an ultraviolet…

High Energy Physics - Phenomenology · Physics 2018-06-13 Oleg Antipin , Francesco Sannino

It is widely believed that chiral symmetry is spontaneously broken at zero temperature in the strong coupling limit of staggered fermions, for any number of colors and flavors. Using Monte Carlo simulations, we show that this conventional…

High Energy Physics - Lattice · Physics 2015-06-11 Philippe de Forcrand , Seyong Kim , Wolfgang Unger

We study the evolution of the coupling in SU(2) gauge field theory with $N_f=4$, 6 and 10 fundamental fermion flavours on the lattice. These values are chosen close to the expected edges of the conformal window, where the theory possesses…

High Energy Physics - Lattice · Physics 2015-03-19 Tuomas Karavirta , Jarno Rantaharju , Kari Rummukainen , Kimmo Tuominen

Universality of various fermion formulations is well established in QCD-like theories defined around the perturbative $g^2=0$ fixed point. These arguments do not apply for conformal systems that exhibit an infrared fixed point at…

High Energy Physics - Lattice · Physics 2018-04-18 Anna Hasenfratz , Claudio Rebbi , Oliver Witzel

We investigate the gauge dynamics of nonsupersymmetric SU(N) gauge theories featuring the simultaneous presence of fermionic matter transforming according to two distinct representations of the underlying gauge group. We bound the regions…

High Energy Physics - Phenomenology · Physics 2014-11-20 Thomas A Ryttov , Francesco Sannino

The domain wall formulation of lattice fermions is expected to support accurate chiral symmetry, even at finite lattice spacing. Here we attempt to use this new fermion formulation to simulate two-flavor, finite temperature QCD near the…

High Energy Physics - Lattice · Physics 2009-10-31 P. Chen , N. Christ , G. Fleming , A. Kaehler , C. Malureanu , R. Mawhinney , G. Siegert , C. Sui , P. Vranas , L. Wu , Y. Zhestkov

I review recent developments in determining the QCD phase diagram by means of lattice simulations. Since the invention of methods to side-step the sign problem a few years ago, a number of additional variants have been proposed, and…

High Energy Physics - Lattice · Physics 2007-05-23 Owe Philipsen

Results from the Columbia lattice group study of the QCD finite temperature phase transition with dynamical domain wall fermions on $16^3 \times 4$ lattices are presented. These results include an investigation of the U(1) axial symmetry…

High Energy Physics - Lattice · Physics 2015-06-25 Pavlos Vranas

Domain wall fermions are a new lattice fermion formulation which preserves the full chiral symmetry of the continuum at finite lattice spacing, up to terms exponentially small in an extra parameter. We discuss the main features of the…

High Energy Physics - Lattice · Physics 2007-05-23 George Tamminga Fleming

We investigate the chiral phase transition at finite temperature (T) in colour SU(3) Quantum Chromodynamics (QCD) with six species of fermions (Nf = 6) in the fundamental representation. The simulations have been performed by using lattice…

High Energy Physics - Lattice · Physics 2011-11-07 Kohtaroh Miura , Maria Paola Lombardo , Elisabetta Pallante

The present knowledge of the QCD phase diagram based on simulations of lattice QCD is summarised. The main questions are whether there is a critical point in the QCD phase diagram and whether it is related to a chiral phase transition. It…

High Energy Physics - Phenomenology · Physics 2011-11-24 Owe Philipsen

The spectrum of twelve-flavor QCD has been studied in details by the LatKMI collaboration. In this proceeding we present our updated results for the spectrum obtained with the HISQ action at two lattice spacings, several volumes and fermion…

We investigate the phase structure of lattice QCD for general number of flavors $N_F$. Based on numerical data combined with the results of the perturbation theory we propose the following picture: When $N_F \ge 17$, there is only one IR…

High Energy Physics - Lattice · Physics 2008-11-26 Y. Iwasaki , K. Kanaya , S. Kaya , S. Sakai , T. Yoshié