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Related papers: A random matrix model for chiral symmetry breaking

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The pattern of chiral symmetry breaking is exploited to compute vector and axial-vector pion matrix elements in a uniform magnetic field. Our results are model independent, and thereby constitute low-energy theorems that must be obeyed by…

High Energy Physics - Phenomenology · Physics 2024-06-04 Prabal Adhikari , Brian C. Tiburzi

The three complex form factors entering the $\Delta\to N\gamma^\ast$ vertex are calculated to ${\cal O}(\epsilon^3)$ in the framework of a chiral effective theory with explicit \Delta(1232) degrees of freedom included. It is shown that the…

High Energy Physics - Phenomenology · Physics 2009-10-31 G. C. Gellas , T. R. Hemmert , C. N. Ktorides , G. I. Poulis

We study the chiral phase transition in the linear sigma model with 2 quark flavors and $N_c$ colors. One-loop calculations predict a first-order phase transition at both $\mu=0$ and $\mu\neq 0$. We also discuss the phase diagram and make a…

High Energy Physics - Phenomenology · Physics 2014-11-17 Neven Bilic , Hrvoje Nikolic

According to the Banks-Casher formula the chiral order parameter is directly related to the spectrum of the Dirac operator. In this lecture, we will argue that some properties of the Dirac spectrum are universal and can be obtained from a…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. J. M. Verbaarschot

The chiral symmetry breaking ($\chi_{SB}$) is one of the most fundamental problems in QCD. In this paper, we calculate quark condensation analytically in a holographic QCD model dual to the Einstein-Maxwell-Dilaton (EMD) system coupled to a…

High Energy Physics - Theory · Physics 2021-02-24 Meng-Wei Li , Yi Yang , Pei-Hung Yuan

We study QCD with twelve light flavors at intermediate values of the bare lattice coupling. We contrast the results for the order parameter with different theoretical models motivated by the physics of the Goldstone phase and of the…

High Energy Physics - Lattice · Physics 2010-12-30 A. Deuzeman , E. Pallante , M. P. Lombardo

The critical endpoint of the QCD phase diagram is usually expected to belong to the chiral critical surface, i.e. the surface of second order transitions bounding the region of first order chiral phase transitions for small quark masses in…

High Energy Physics - Phenomenology · Physics 2009-11-18 Owe Philipsen

We study the finite-temperature phase structure and the transition temperature of QCD with two flavors of dynamical quarks on a lattice with the temporal size $N_t=4$, using a renormalization group improved gauge action and the Wilson quark…

We investigate the eigenvalue spectrum of the staggered Dirac matrix in full QCD with two colors and finite chemical potential. Along the strong-coupling axis up to the temperature phase transition, the low-lying Dirac spectrum is well…

High Energy Physics - Lattice · Physics 2007-05-23 Elmar Bittner , Maria-Paola Lombardo , Harald Markum , Rainer Pullirsch

The restoration of chiral symmetry at finite density and/or temperature is investigated in a wide class of one-gluon exchange models in the instantaneous approximation. If the effective quark interaction is less divergent than $1/k^2$ for…

High Energy Physics - Phenomenology · Physics 2009-10-28 Kurt Langfeld , Hugo Reinhardt

We generated configurations with the parametrized fixed-point Dirac operator D_{FP} on a (1.6 fm)^4 box at a lattice spacing a=0.13 fm. We compare the distributions of the three lowest k=1,2,3 eigenvalues in the nu= 0,1,2 topological…

High Energy Physics - Lattice · Physics 2014-11-18 P. Hasenfratz , D. Hierl , V. Maillart , F. Niedermayer , A. Schäfer , C. Weiermann , M. Weingart

We compute the low-lying spectrum of the staggered Dirac operator above and below the finite temperature phase transition in both quenched QCD and in dynamical four flavor QCD. In both cases we find, in the high temperature phase, a density…

High Energy Physics - Lattice · Physics 2009-10-31 P. H. Damgaard , U. M. Heller , R. Niclasen , K. Rummukainen

The real-time dynamics of chiral phase transition is investigated in a two-flavor ($N_f=2$) soft-wall AdS/QCD model. To understand the dynamics of thermalization, we quench the system from initial states deviating from the equilibrium…

High Energy Physics - Phenomenology · Physics 2023-04-19 Xuanmin Cao , Jingyi Chao , Hui Liu , Danning Li

We examine quenched chiral logarithms in lattice QCD with overlap Dirac quarks. From our data of m_pi^2, we determine the coefficient of quenched chiral logarithm delta = 0.203(14), 0.176(17), 0.193(17) and 0.200(13) for lattices of sizes…

High Energy Physics - Lattice · Physics 2011-02-16 Ting-Wai Chiu , Tung-Han Hsieh

We derive the critical behavior of a CA traffic flow model using an order parameter breaking the symmetry of the jam-free phase. Random braking appears to be the symmetry-breaking field conjugate to the order parameter. For $v_{\max}=2$, we…

Disordered Systems and Neural Networks · Physics 2009-10-31 N. Boccara , H. Fukś

Heavy quark symmetry predicts the value of $B \rightarrow D$ and $B \rightarrow D^*$ transition matrix elements of the current $\bar c \gamma_\mu (1 - \gamma_5)b$, at zero recoil (where in the rest frame of the $B$ the $D$ or $D^*$ is also…

High Energy Physics - Phenomenology · Physics 2009-09-15 L. Randall , M. B. Wise

In the $\epsilon$-domain of QCD we have obtained exact analytical expressions for the eigenvalue density of the Dirac operator at fixed $\theta \ne 0$ for both one and two flavors. These results made it possible to explain how the different…

High Energy Physics - Lattice · Physics 2018-07-31 Mario Kieburg , Jacobus Verbaarschot , Tilo Wettig

Chiral random matrix theory makes very detailed predictions for the spectral correlations of the QCD Dirac operator, both in the bulk of the spectrum and near zero virtuality. These predictions have been successfully tested in lattice QCD…

High Energy Physics - Lattice · Physics 2007-05-23 Tilo Wettig

We analyze (using a chiral effective Lagrangian model) the scalar and pseudoscalar meson mass spectrum of QCD at finite temperature, above the chiral transition at $T_c$, looking, in particular, for signatures of a possible breaking of the…

High Energy Physics - Phenomenology · Physics 2014-10-15 Enrico Meggiolaro

For QCD at non-zero chemical potential $\mu$, the Dirac eigenvalues are scattered in the complex plane. We define a notion of ordering for individual eigenvalues in this case and derive the distributions of individual eigenvalues from…

High Energy Physics - Lattice · Physics 2009-01-14 Gernot Akemann , Jacques Bloch , Leonid Shifrin , Tilo Wettig