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Related papers: Leading Order QCD Shear Viscosity from the 3PI Eff…

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We study the production amplitude for the reaction NN->NNpi up to next--to--leading order in chiral perturbation theory using a counting scheme that takes into account the large scale introduced by the initial momentum. In particular we…

Nuclear Theory · Physics 2009-11-11 V. Lensky , V. Baru , J. Haidenbauer , C. Hanhart , A. E. Kudryavtsev , U. -G. Meißner

We have computed shear viscosity coefficient for hot and dense QCD matter within Polyakov loop extended quark meson(PQM) model for three flavors. Viscosity coefficient is estimated using Boltzmann equation within the relaxation time…

Nuclear Theory · Physics 2021-12-22 Ritesh Ghosh

In a relativistic setting, hydrodynamic calculations which include shear viscosity (which is first order in an expansion in gradients of the flow velocity) are unstable and acausal unless they also include terms to second order in…

High Energy Physics - Phenomenology · Physics 2009-07-29 Mark Abraao York , Guy D. Moore

The remarkably small shear viscosity to entropy density ratio $\eta/s < 0.5$ of the quark-gluon plasma (QGP) is a key insight from heavy ion experiments. Nonetheless, the basic understanding of this `observable' still seems to be…

High Energy Physics - Phenomenology · Physics 2018-08-15 Greg Jackson , Andre Peshier

We compute the shear viscosity of two-flavor QCD plasma in an external magnetic field in perturbative QCD at leading log order, assuming that the magnetic field is weak or soft: $eB\sim g^4\log(1/g)T^2$. We show that the shear viscosity…

High Energy Physics - Phenomenology · Physics 2018-04-04 Shiyong Li , Ho-Ung Yee

We compute the leading mass corrections to the high-energy behavior of the massive quark vector form factor to three loops in QCD in the double-logarithmic approximation.

High Energy Physics - Phenomenology · Physics 2017-06-28 Tao Liu , Alexander A. Penin , Nikolai Zerf

The 3-loop heavy flavor corrections to deep-inelastic scattering are essential for consistent next-to-next-to-leading order QCD analyses. We report on the present status of the calculation of these corrections at large virtualities $Q^2$.…

High Energy Physics - Phenomenology · Physics 2014-11-21 J. Blümlein , A. De Freitas , C. Schneider

In the framework of analytic approach to QCD, which has been recently intensively developed, the dependence of nonperturbative contributions in a running coupling of strong interaction on initial perturbative approximation to 3-loop order…

High Energy Physics - Phenomenology · Physics 2007-05-23 Aleksey I. Alekseev

We work with $\phi^4$ theory and study the 4PI effective action at 3-loop order. We discuss the relationship between the equations of motion obtained by taking functional derivatives of the effective action with respect to the variational…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. E. Carrington

We calculate shear viscosity and bulk viscosity in SU(3) gauge theory on the lattice at $1.5 \,T_c$. The viscosities are extracted via a Kubo formula from the reconstructed spectral function which we determine from the Euclidean-time…

High Energy Physics - Lattice · Physics 2023-07-13 Luis Altenkort , Alexander M. Eller , Anthony Francis , Olaf Kaczmarek , Lukas Mazur , Guy D. Moore , Hai-Tao Shu

The real and imaginary part of the vacuum polarisation function $\Pi(q^2)$ induced by a massive quark is calculated in perturbative QCD up to order $\alpha_s^2$. The method is described and the results are presented. This extends the…

High Energy Physics - Phenomenology · Physics 2010-04-06 K. G. Chetyrkin , J. H. Kuehn , M. Steinhauser

We compute the pressure of hot quantum electrodynamics from the two-loop truncation of the 2PI effective action. Since the 2PI resummation guarantees gauge-fixing independence only up to the order of the truncation, our result for the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Szabolcs Borsanyi , Urko Reinosa

We accomplish for the first time the two-loop computation of the leading-twist contribution to the pion electromagnetic form factor by employing the effective field theory formalism rigorously. The next-to-next-to-leading-order…

High Energy Physics - Phenomenology · Physics 2024-11-07 Yao Ji , Bo-Xuan Shi , Jian Wang , Ye-Fan Wang , Yu-Ming Wang , Hui-Xin Yu

We describe in detail the implementation of a systematic perturbative approach to observables in the QCD gradient-flow formalism. This includes a collection of all relevant Feynman rules of the five-dimensional field theory and the…

High Energy Physics - Lattice · Physics 2022-10-12 Johannes Artz , Robert V. Harlander , Fabian Lange , Tobias Neumann , Mario Prausa

We compute the purely gluonic contribution to the static QCD potential at three--loop order. This completes the computation of the static potential at this order.

High Energy Physics - Phenomenology · Physics 2010-04-06 C. Anzai , Y. Kiyo , Y. Sumino

We review progress in calculating one-loop scattering amplitudes required for next-to-leading-order corrections to QCD processes. The underlying technical developments include the spinor helicity formalism, color decompositions,…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , L. Dixon , D. A. Kosower

Among the key features of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions at RHIC is its very low shear viscosity, indicative of the properties of a near-ideal fluid, and a large opacity demonstrated by jet…

Nuclear Theory · Physics 2010-12-09 John Fuini , Nasser S. Demir , Dinesh K. Srivastava , Steffen A. Bass

Second-order dissipative hydrodynamic equations for each component of a multi-component system are derived using the entropy principle. Comparison of the solutions with kinetic transport results demonstrates validity of the obtained…

High Energy Physics - Theory · Physics 2015-06-05 Andrej El , Ioannis Bouras , Christian Wesp , Zhe Xu , Carsten Greiner

Motivated by isotropization of QCD matter in the initial stages of heavy-ion collisions, we consider a system of scalar fields that undergoes a boost invariant longitudinal expansion. We use the framework of the two-particle irreducible…

High Energy Physics - Phenomenology · Physics 2024-03-19 François Gelis , Sigtryggur Hauksson

We investigate Lipatov's QCD effective action for the QCD high energy limit and propose a pole prescription for higher order induced vertices. The latter can be used in the evaluation of loop corrections to high energy factorized matrix…

High Energy Physics - Phenomenology · Physics 2015-06-03 Martin Hentschinski