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Related papers: Is there still a strong CP problem?

200 papers

We study the properties of the B-->pi and B-->K transition form factors in partially quenched QCD by using the approach of partially quenched chiral perturbation theory combined with the static heavy quark limit. We show that the form…

High Energy Physics - Lattice · Physics 2014-11-17 Damir Becirevic , Sasa Prelovsek , Jure Zupan

We construct the effective potential for a QCD-like theory using the auxiliary field method. The chiral phase transition exhibited by the model at finite temperature and the quark chemical potential is studied from the viewpoint of the…

High Energy Physics - Phenomenology · Physics 2016-09-06 Y. Hashimoto , Y. Tsue , H. Fujii

We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then…

High Energy Physics - Phenomenology · Physics 2018-09-19 H. Abuki

Models that combine Abelian horizontal symmetries and spontaneous CP violation can (i) explain the smallness and hierarchy in quark parameters; (ii) satisfactorily suppress supersymmetric contributions to flavor changing neutral current…

High Energy Physics - Phenomenology · Physics 2009-10-28 Yosef Nir , Riccardo Rattazzi

We describe the chiral phase transition for vector-like SU(N) gauge theories as a function of the number of quark flavors Nf by making use of an anomaly-induced effective potential. The potential depends explicitly on the full beta-function…

High Energy Physics - Phenomenology · Physics 2010-12-13 Francesco Sannino

We investigate a composite model of spontaneous CP violation based on a new supersymmetric QCD as a solution to the strong CP problem. The scalar components of the meson chiral superfields obtain complex vacuum expectation values to break…

High Energy Physics - Phenomenology · Physics 2024-06-04 Shota Nakagawa , Yuichiro Nakai , Yaoduo Wang

We study the QCD phase diagram, in particular we study the critical points of the two main QCD phase transitions, confinement and chiral symmetry breaking. Confinement drives chiral symmetry breaking, and, due to the finite quark mass, at…

High Energy Physics - Phenomenology · Physics 2010-04-20 Pedro Bicudo

The nontrivial topological structure of the QCD gauge vacuum generates a CP breaking term in the QCD Lagrangian. However, measurements of the neutron electric dipole moment have demonstrated that the term's coefficient is unnaturally small,…

High Energy Physics - Lattice · Physics 2007-05-23 Daniel R. Nelson

We study chiral symmetry breaking for fundamental charged fermions coupled electromagnetically to photons with the inclusion of four-fermion contact self-interaction term. We employ multiplicatively renormalizable models for the photon…

High Energy Physics - Phenomenology · Physics 2013-05-30 F. Akram , A. Bashir , L. X. Gutierrez-Guerrero , B. Masud , J. Rodriguez-Quintero , C. Calcaneo-Roldan , M. E. Tejeda-Yeomans

We present simple effective theory of quark masses, mixing and CP violation with level $N=3$ ($A_4$) modular symmetry, which provides solution to the strong CP problem without the need for an axion. The vanishing of the strong CP-violating…

High Energy Physics - Phenomenology · Physics 2024-07-03 S. T. Petcov , M. Tanimoto

I review recent results obtained within chiral effective models, on the phase structure of hot quark matter in a strong magnetic background. After a brief introduction, I focus on the results obtained within two chiral models improved with…

High Energy Physics - Phenomenology · Physics 2011-09-06 Marco Ruggieri

I discuss several aspects of CP non-invariance in the strongly interacting theory of quarks and gluons. I use a simple effective Lagrangian technique to map out the region of quark masses where CP symmetry is spontaneously broken. I then…

High Energy Physics - Theory · Physics 2007-05-23 Michael Creutz

We study the relation between the scale of chiral symmetry spontaneously breaking and constituent quark mass. We argue that this relation partly reveals strong interaction origination of chiral symmetry breaking. We show that the relation…

High Energy Physics - Phenomenology · Physics 2007-05-23 Mu-Lin Yan , Yi-Bin Huang , Xiao-Jun Wang

The ratio of the sigma mass to the pion mass at finite temperatures and densities provides for a quantitative signal of chiral symmetry breaking. We calculate this ratio by using an extension to finite chemical potential of the field…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. Barducci , R. Casalbuoni , R. Gatto , G. Pettini

Dynamical chiral-symmetry breaking in QCD is studied with the Schwinger-Dyson (SD) formalism based on lattice QCD data, i.e., LQCD-based SD formalism. We extract the SD kernel function $K(p^2)$ in an Ansatz-independent manner from the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Hideaki Iida , Makoto Oka , Hideo Suganuma

The role of the contribution from the fermion mass term in the axial vector Ward identity in generating the U(1) axial anomaly, both local and global, is elucidated. Gauge invariance requires the fermion to decouple from the gauge field if…

High Energy Physics - Theory · Physics 2007-05-23 H. Banerjee

In the previous work, we have shown that the SU(2) chiral symmetry recovered above the critical temperature gives a strong constraint on the Dirac eigenvalue spectrum and this constraint is strong enough for a set of anomalous U(1) chiral…

High Energy Physics - Lattice · Physics 2013-12-06 Sinya Aoki , Hidenori Fukaya , Yusuke Taniguchi

We investigate the chiral phase transition in rotating quark matter with chiral imbalance using the two-flavor Nambu-Jona-Lasinio (NJL) model regularized by the Medium Separation Scheme (MSS). Our numerical calculations demonstrate that the…

High Energy Physics - Phenomenology · Physics 2026-03-31 Huang-Jing Zheng , Peng Nan , Sheng-Qin Feng

We explore a possible phase where chiral $SU(2)_L \times SU(2)_R$ symmetry is spontaneously broken while its center $Z_2$ symmetry remains unbroken and its consequence on thermal quantities. In this phase, chiral symmetry breaking is driven…

High Energy Physics - Phenomenology · Physics 2010-02-04 M. Harada , C. Sasaki , S. Takemoto

We formulate the necessary conditions for a scalar potential to exhibit spontaneous CP violation. Associated with each complex scalar field is a U(1) symmetry that may be explicitly broken by terms in the scalar potential (called spurions).…

High Energy Physics - Phenomenology · Physics 2015-03-20 Howard E. Haber , Ze'ev Surujon