English
Related papers

Related papers: The S parameter in a technicolour model with expli…

200 papers

We consider the NJL model as an effective quark theory to describe the interaction which is responsible for the quark flavor dynamics at intermediate energies. In addition to the usual ultraviolet cut-off which is necessary since the model…

High Energy Physics - Phenomenology · Physics 2009-10-28 D. Ebert , T. Feldmann , H. Reinhardt

We study dynamical chiral symmetry breaking for quarks in the fundamental representation of $SU(N_c)$ for $N_f$ number of light quark flavors. We also investigate the phase diagram of quantum chromodynamics at finite temperature $T$ and/or…

High Energy Physics - Phenomenology · Physics 2021-07-07 Aftab Ahmad , Adnan Bashir , Marco A. Bedolla , J. J. Cobos-Martínez

In this paper, chiral symmetry breaking and its restoration are investigated in the mean field approximation of Nambu--Jona-Lasinio model. A first-order phase transition exists at low temperature, but is smeared out at high temperature. We…

High Energy Physics - Phenomenology · Physics 2013-12-09 Yi-lun Du , Zhu-fang Cui , Yong-hui Xia , Hong-shi Zong

The chiral symmetry of QCD requires energy-dependent pionic strong interactions at low energies. This constraint, however, is not fulfilled by the usual Breit--Wigner parameterization of pionic resonances, leading to masses larger than the…

High Energy Physics - Phenomenology · Physics 2019-06-12 Meng-Lin Du , Feng-Kun Guo , Ulf-G. Meißner

We explore the inhomogeneous QCD phases at finite density and temperature using a (3+1)-dimensional Nambu-Jona-Lasinio (NJL) model in the large Nc limit with an additional attractive tensor-tensor interaction channel. For single modulated…

Nuclear Theory · Physics 2013-04-04 Bo Feng , Efrain J. Ferrer , Vivian de la Incera

The Banks--Casher relation links the spontaneous breaking of chiral symmetry in QCD to the presence of a non-zero density of quark modes at the low end of the spectrum of the Dirac operator. Spectral observables like the number of modes in…

High Energy Physics - Lattice · Physics 2009-03-31 Leonardo Giusti , Martin Lüscher

This note presents constraints on Standard Model parameters using published and preliminary precision electroweak results measured at the electron-positron colliders LEP and SLC. The results are compared with precise electroweak…

We study the radiative electroweak symmetry breaking and the relic abundance of neutralino dark matter in the supersymmetric type I seesaw model. In this model, there exist threshold corrections to Higgs bilinear terms coming from heavy…

High Energy Physics - Phenomenology · Physics 2010-01-22 Sin Kyu Kang , Akina Kato , Takuya Morozumi , Norimi Yokozaki

We discuss the truncation of low energy effective action of QCD below the chiral symmetry breaking (CSB) scale, including all operators of dimensionality less or equal to 6 which can be built with quark and chiral fields. We perform its…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. A. Andrianov , D. Espriu , R. Tarrach

In previous publications we have analyzed the strong and electromagnetic decays of heavy mesons and heavy baryons in a formalism which incorporates heavy-quark and chiral symmetries. There are two possible symmetry-breaking effects on the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Hai-Yang Cheng , Chi-Yee Cheung , Guey-Lin Lin , Y. C. Lin , Tung-Mow Yan , Hoi-Lai Yu

In the first part of these lectures, I consider chiral perturbation theory in the presence of matter fields. It allows to systematically work out the consequences of the broken chiral symmetry of QCD. As examples, threshold pion photo- and…

High Energy Physics - Phenomenology · Physics 2015-06-25 Ulf-G. Meißner

Under a hypothesis of classically conformal theories, we investigate the minimal B-L extended Standard Model, which naturally provides the seesaw mechanism for explaining tiny neutrino masses. In this setup, the radiative gauge symmetry…

High Energy Physics - Phenomenology · Physics 2014-11-18 Satoshi Iso , Nobuchika Okada , Yuta Orikasa

To describe the chiral magnetic effect, the chiral chemical potential $\mu_5$ is introduced to imitate the impact of topological charge changing transitions in the quark-gluon plasma under the influence of an external magnetic field. We…

High Energy Physics - Phenomenology · Physics 2022-10-07 Alexander M. Czajka , Zhong-Bo Kang , Yuxuan Tee , Fanyi Zhao

The masses of low-lying S-wave mesons are evaluated in a constituent quark model (CQM) where the Cornell-like potential and one-gluon exchange spin-spin interaction are employed. To make the model applicable to both the light and heavy…

High Energy Physics - Phenomenology · Physics 2023-04-14 Zheng Zhao , Kai Xu , Attaphon Kaewsnod , Xuyang Liu , Ayut Limphirat , Yupeng Yan

Effect of magnetic field on chiral symmetry breaking in a 3-flavor Nambu Jona Lasinio (NJL) model at finite temperature and densities is considered here using an explicit structure of ground state in terms of quark and antiquark…

High Energy Physics - Phenomenology · Physics 2011-07-26 Bhaswar Chatterjee , Hiranmaya Mishra , Amruta Mishra

By considering the background field method we calculate one-loop polarization corrections to the coupling constant of the flavor-U(5) Nambu-Jona-Lasinio (NJL) model with degenerate up and down quarks. They break flavor and chiral…

High Energy Physics - Phenomenology · Physics 2024-08-16 Willian F. de Sousa , Fabio L. Braghin

In this paper we discuss the combined effects on nuclear matter properties of the quark confinement mechanism in nucleon and of the chiral effective potential resulting from the spontaneous breaking of the chiral symmetry in nuclear matter.…

Nuclear Theory · Physics 2023-04-04 G. Chanfray , H. Hansen , J. Margueron

We show that the S parameter is not finite in theories of electroweak symmetry breaking in a slice of anti--de Sitter five-dimensional space, with the light fermions localized in the ultraviolet. We compute the one-loop contributions to S…

High Energy Physics - Phenomenology · Physics 2014-11-18 Gustavo Burdman , Leandro Da Rold

Dynamical symmetry breaking is investigated for a four-fermion Nambu-Jona-Lasinio model in external electromagnetic and gravitational fields. An effective potential is calculated in the leading order of the large-N expansion using the…

High Energy Physics - Theory · Physics 2009-10-31 E. Elizalde , Yu. I. Shil'nov

This note presents constraints on Standard Model parameters using published and preliminary precision electroweak results measured at the electron-positron colliders LEP and SLC. The results are compared with precise electroweak…