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Related papers: Improved soft-wall model with a negative dilaton

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We revisit standard arguments for hyperscaling of the spectrum when a non-zero fermion mass is introduced to a gauge-fermion theory which is conformal in the infrared limit. With some general assumptions, we argue that the induced…

High Energy Physics - Theory · Physics 2023-08-08 Roman Marcarelli , Nicholas Miesch , Ethan T. Neil

Phenomenological AdS/QCD models, like hard wall and soft wall, provide hadronic mass spectra in reasonable consistency with experimental and (or) lattice results. These simple models are inspired in the AdS/CFT correspondence and assume…

High Energy Physics - Theory · Physics 2016-11-01 Nelson R. F. Braga , M. A. Martin Contreras , Saulo Diles

Soft-pion theorems are used to show how chiral symmetry constrains the contributions of low-momentum pions to the quark condensate, the pion decay constant and hadron masses, all of which have been proposed as signals of partial restoration…

Nuclear Theory · Physics 2007-05-23 Michael C. Birse

I analyse the hypothesis that deviations from the linear meson mass spectra appear due to the dynamical chiral symmetry breaking in QCD. It is shown that the linear mass spectrum for the light, non-strange vector and axial-vector mesons is…

High Energy Physics - Phenomenology · Physics 2015-06-25 S. S. Afonin

We propose a mechanism for instanton induced chiral symmetry breaking in QCD with fundamental scalars. The model Lagragian that we use has the same symmetry properties as QCD. The scalar fields develop vacuum expectation values at a…

High Energy Physics - Phenomenology · Physics 2011-09-13 Rahul Basu , R. Parthasarathy

We study the chiral symmetry breaking and restoration in $ (2+1) $-dimensional gauge theories from the holographic hard and softwall models. We describe the behavior of the chiral condensate in the presence of an external magnetic field for…

High Energy Physics - Theory · Physics 2018-11-13 Diego M. Rodrigues , Danning Li , Eduardo Folco Capossoli , Henrique Boschi-Filho

We consider a holographic description of the chiral symmetry breaking in an external magnetic field in $ (2+1) $-dimensional gauge theories from the softwall model using an improved dilaton field profile given by $\Phi(z) = - kz^2 +…

High Energy Physics - Phenomenology · Physics 2020-02-06 Diego M. Rodrigues , Danning Li , Eduardo Folco Capossoli , Henrique Boschi-Filho

The mass spectrum of Delta resonances is compared to predictions based on three quark-model variants, to predictions assuming that chiral symmetry is restored in high-mass baryon resonances, and to predictions derived from AdS/QCD. The…

High Energy Physics - Phenomenology · Physics 2009-09-29 E. Klempt

We study the properties of the dilaton in a soft-wall background using two solutions of the Einstein equations. These solutions contain an asymptotically AdS metric with a nontrivial scalar profile that causes both the spontaneous breaking…

High Energy Physics - Theory · Physics 2015-02-26 Peter Cox , Tony Gherghetta

The temperature dependence of quark and gluon condensates in QCD as precursor of the chiral and deconfining phase transition is modelled with a conformally extended non-linear sigma-model including broken chiral and scale invariance. The…

High Energy Physics - Phenomenology · Physics 2009-10-30 N. O. Agasian , D. Ebert , E. -M. Ilgenfritz

QCD at nonzero isospin chemical potentials has phenomenological relevance for a series of physical systems and provides an ideal testground for the modeling of dense strongly interacting matter. The two-flavor quark-meson model is known to…

High Energy Physics - Phenomenology · Physics 2025-09-09 Bastian B. Brandt , Volodymyr Chelnokov , Gergely Endrodi , Gergely Marko , Daniel Scheid , Lorenz von Smekal

Multiple lattice evidences support the existence of a confining but chirally symmetric regime of QCD above the chiral symmetry restoration crossover at Tch ~ 155 MeV. This regime is characterised by an approximate chiral spin symmetry of…

High Energy Physics - Phenomenology · Physics 2024-05-08 L. Ya. Glozman , A. V. Nefediev , R. Wagenbrunn

We consider an improved soft-wall AdS/QCD model coupled to an Einstein-dilaton system, which offers a way to study the deconfining and chiral transitions simultaneously. The correlation between these two transitions has been investigated in…

High Energy Physics - Phenomenology · Physics 2022-03-02 Ying-Ying Li , Xing-Lin Liu , Xin-Yi Liu , Zhen Fang

We simulate Lattice QED in a constant external magnetic field using the RHMC algorithm. We seek evidence for chiral symmetry breaking predicted by truncated Schwinger-Dyson methods. Since the predicted values of the dynamical electron mass…

High Energy Physics - Lattice · Physics 2022-10-21 D. K. Sinclair , J. B. Kogut

This article gives details of our proposal to replace ordinary chiral $SU(3)_L\times SU(3)_R$ perturbation theory $\chi$PT$_3$ by 3-flavor chiral-scale perturbation theory $\chi$PT$_\sigma$. In $\chi$PT$_\sigma$, amplitudes are expanded at…

High Energy Physics - Phenomenology · Physics 2015-02-25 R. J. Crewther , Lewis C. Tunstall

We give a further study on chiral phase diagram in the improved soft-wall AdS/QCD model with $2+1$ flavors. The equations of motion for the octet pseudoscalar, vector and axial-vector mesons are derived to compute the octet meson spectra…

High Energy Physics - Phenomenology · Physics 2019-09-18 Zhen Fang , Yue-Liang Wu , Lin Zhang

Classical conformal invariance of QCD in the chiral limit is broken explicitly by scale anomaly. As a result, the lightest scalar particle (scalar glueball, or dilaton) in QCD is not light, and cannot be described as a Goldstone boson.…

High Energy Physics - Phenomenology · Physics 2015-05-13 Dmitri Kharzeev , Eugene Levin , Kirill Tuchin

In this work we present the results from numerical simulations of an interacting ensemble of instanton-dyons in the $SU(3)$ gauge group with $N_f=2$ flavors of massless quarks. Dynamical quarks are included via the effective interactions…

High Energy Physics - Phenomenology · Physics 2021-12-01 Dallas DeMartini , Edward Shuryak

Employing functional approaches the infrared behaviour of Landau gauge QCD vertex functions is investigated. Results for the ghost-gluon, three-gluon and quark-gluon vertex functions are presented. As can be analytically shown a linear…

High Energy Physics - Phenomenology · Physics 2008-11-26 Reinhard Alkofer , Christian S. Fischer , Felipe J. Llanes-Estrada , Kai Schwenzer

The chiral phase boundary of nuclear matter is expected to have a critical point where the rapid crossover of lattice methods at zero chemical potential becomes a first-order phase transition. Phenomenological models based on the AdS/CFT…

High Energy Physics - Phenomenology · Physics 2024-04-17 Sean P. Bartz , Robert C. Meadows , Glenn Brock