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Related papers: QCD at \theta \sim \pi

200 papers

We investigate the phase structure of QCD with 3 degenerate quark flavors as function of the degenerate quark masses at vanishing baryon number density. We use the Highly Improved Staggered Quarks on lattices with temporal extent $N_{t}=6$…

High Energy Physics - Lattice · Physics 2017-04-19 A. Bazavov , H. -T. Ding , P. Hegde , F. Karsch , E. Laermann , Swagato Mukherjee , P. Petreczky , C. Schmidt

We perform a systematic study of the modifications to the QCD vacuum energy density $\epsilon_{vac}$ in the zero-temperature case ($T=0$) caused by a small, but non-zero, value of the parameter $\theta$, using different effective Lagrangian…

High Energy Physics - Phenomenology · Physics 2018-10-10 Francesco Luciano , Enrico Meggiolaro

We study the QCD vacuum orientation angles in correlation with the strong CP phases. A vacuum alignment equation of the dynamical chiral symmetry breaking is derived based on the anomalous Ward identity. It is emphasized that a chiral…

High Energy Physics - Phenomenology · Physics 2015-06-25 Zheng Huang , K. S. Viswanathan , D. D. Wu

We determine the phase diagram of QCD on the \mu-T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations…

High Energy Physics - Lattice · Physics 2011-04-05 G. Endrodi , Z. Fodor , S. D. Katz , K. K. Szabo

Parameters and light fields of the QCD Lagrangian with two heavy flavours, b and c, are related to those in the low-energy effective theory without these flavours, to three-loop accuracy taking into account the exact dependence on m_c/m_b.…

High Energy Physics - Phenomenology · Physics 2012-05-29 Andrey Grozin , Maik Höschele , Jens Hoff , Matthias Steinhauser

The Multiple Point Principle, according to which there exist many vacuum states with the same energy density, is put forward as a fine-tuning mechanism. By assuming the existence of three degenerate vacua, we derive the hierarchical ratio…

High Energy Physics - Phenomenology · Physics 2015-06-25 C. D. Froggatt

The phase structure of two-color QCD is examined as a function of the chemical potential and the number of light quark flavors. We consider effective Lagrangians for two-color QCD containing the Goldstone excitations, spin-one particles and…

High Energy Physics - Phenomenology · Physics 2009-11-07 J. T. Lenaghan , F. Sannino , K. Splittorff

We investigate the chiral phase transition of a QCD-like theory, based the shape change of the effective potential near the critical point. The potential is constructed with the auxiliary field method, and a source term coupled to the field…

High Energy Physics - Phenomenology · Physics 2010-11-26 Y. Tsue , H. Fujii , Y. Hashimoto

We investigate the deconfining phase transition in SU(3) pure gauge theory and in full QCD with two flavors of staggered fermions. The phase transition is detected by measuring the free energy in presence of an abelian monopole background…

High Energy Physics - Lattice · Physics 2009-11-10 Paolo Cea , Leonardo Cosmai , Massimo D'Elia

We present results for the static interquark potential, light meson and baryon masses, and light pseudoscalar meson decay constants obtained from simulations of domain wall QCD with one dynamical flavour approximating the $s$ quark, and two…

We study the phase structure of mixed-action QCD with two Wilson sea quarks and two chiral valence quarks, starting from the chiral lagrangian. A priori, the effective theory allows for a rich phase structure, including a phase with a…

High Energy Physics - Lattice · Physics 2011-10-13 Oliver Baer , Maarten Golterman , Yigal Shamir

The two-flavor quark-meson model is used as a low-energy effective model for QCD to study inhomogeneous chiral condensates at finite quark chemical potential $\mu$ in a constant magnetic background $B$. We determine the parameters of the…

High Energy Physics - Phenomenology · Physics 2017-10-24 Jens O. Andersen , Patrick Kneschke

We introduce a random matrix model with the symmetries of QCD with two colors at nonzero isospin and baryon chemical potentials and temperature. We analyze its phase diagram and find phases with condensation of pion and diquark states in…

High Energy Physics - Phenomenology · Physics 2009-11-10 B. Klein , D. Toublan , J. J. M. Verbaarschot

We calculate the QCD equation of state for temperatures corresponding to the transition region with physical mass values for two degenerate light quark flavors and a strange quark using an improved staggered fermion action (p4-action) on…

High Energy Physics - Lattice · Physics 2010-04-29 M. Cheng , S. Ejiri , P. Hegde , F. Karsch , O. Kaczmarek , E. Laermann , R. D. Mawhinney , C. Miao , S. Mukherjee , P. Petreczky , C. Schmidt , W. Soeldner

We have simulated QCD using 2+1 flavors of domain wall quarks on a $(2.74 {\rm fm})^3$ volume with an inverse lattice scale of $a^{-1} = 1.729(28)$ GeV. The up and down (light) quarks are degenerate in our calculations and we have used four…

Precise measurement of the $\pi\pi$-phase shift $\delta^0_0(E)$ at very low energies would provide, for the first time, the experimental evidence in favour of or against the existence of a large quark condensate in the QCD vacuum, which is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jan Stern

In this work, extending a previous study at zero temperature ($T=0$), we perform a systematic study of the modifications to the QCD vacuum energy density $\epsilon_{vac}$ in the finite-temperature case, above the chiral transition at $T_c$,…

High Energy Physics - Phenomenology · Physics 2019-06-18 Enrico Meggiolaro

QCD with three degenerate quark flavours at zero baryon density exhibits a first order thermal phase transition for small quark masses, which changes to a smooth crossover for some critical quark mass m^c_0, i.e. the chiral critical point.…

High Energy Physics - Lattice · Physics 2008-11-26 Philippe de Forcrand , Owe Philipsen

We examine the phase structure of a QCD-like theory at $\bar\theta =\pi$ obtained from supersymmetric $SU(N)$ QCD perturbed by a small amount of supersymmetry breaking via anomaly mediation (AMSB QCD). The spectrum of this theory matches…

High Energy Physics - Phenomenology · Physics 2024-12-17 Csaba Csáki , Maximilian Ruhdorfer , Taewook Youn

As a successive work to [Phys.Rev.D 102 (2020), 034034], we derive the $1/m_Q$ corrections to chiral effective Lagrangian for heavy-light mesons from QCD under proper approximations. The low energy constants in the effective Lagrangian are…

High Energy Physics - Phenomenology · Physics 2020-12-08 Qing-Sen Chen , Hui-Feng Fu , Yong-Liang Ma , Qing Wang