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The quark contribution to the free energy of a hot quark-gluon plasma is calculated to leading order in hard-thermal-loop (HTL) perturbation theory. This method selectively resums higher order corrections associated with plasma effects,…

High Energy Physics - Phenomenology · Physics 2009-10-31 Jens O. Andersen , Eric Braaten , Michael Strickland

We perform a two-loop calculation in Light Cone Perturbation Theory (LCPT) to evaluate the next-to-leading order nonsinglet splitting function. Our calculation demonstrates the methodology and feasibility of performing higher order…

High Energy Physics - Phenomenology · Physics 2026-01-16 Tuomas Lappi , Risto Paatelainen , Mikko Seppälä

We perform a detailed analysis of the predictions of resummed perturbation theory for the pressure and the second-, fourth-, and sixth-order diagonal quark number susceptibilities in a hot and dense quark-gluon plasma. First, we present an…

High Energy Physics - Phenomenology · Physics 2013-12-24 Sylvain Mogliacci , Jens O. Andersen , Michael Strickland , Nan Su , Aleksi Vuorinen

The successive perturbative estimates of the pressure of QCD at high temperature T show no sign of convergence, unless the coupling constant g is unrealistically small. Exploiting known results of an effective field theory which separates…

High Energy Physics - Phenomenology · Physics 2009-11-10 J. -P. Blaizot , E. Iancu , A. Rebhan

In this paper we study the production of energetic di-leptons. We calculate the rate for 2 $\to$ 2 processes. The log term is obtained analytically and the constant term is calculated numerically. When the photon mass is of the order of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. E. Carrington , A. Gynther , P. Aurenche

We calculate the imaginary part of the retarded two-loop self-energy of a static vector boson in a plasma of quarks and gluons of temperature T, using the imaginary time formalism. We recombine various cuts of the self-energy to generate…

High Energy Physics - Phenomenology · Physics 2010-01-15 A. Majumder , C. Gale

Within the real-time formalism (RTF) of thermal field theory,we apply the hard thermal loop (HTL) resummation technique to calculating effective two-loop thermodynamic potential in quark-gluon plasma (QGP) and its renormalization. The…

High Energy Physics - Phenomenology · Physics 2007-05-23 Wang Xin , Li Jiarong

Two recent attempts for overcoming the poor convergence of the perturbation expansion of the thermodynamic potentials of QCD are discussed: an HTL-adaption of ``screened perturbation theory'' and approximately self-consistent HTL…

High Energy Physics - Phenomenology · Physics 2017-08-23 A. Rebhan

Self-consistent approximations allowing the calculation of the entropy and the baryon density of a quark-gluon plasma are presented. These approximations incorporate the essential physics of the hard thermal loops, involve only…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. -P. Blaizot , E. Iancu , A. Rebhan

The static and dynamic chiral susceptibilities in the quark-gluon plasma are calculated within the lowest order perturbative QCD at finite temperature and the Hard Thermal Loop resummation technique using an effective quark propagator.…

High Energy Physics - Phenomenology · Physics 2009-11-07 Purnendu Chakraborty , Munshi G. Mustafa , Markus H. Thoma

The hard-thermal-loop perturbation theory (HTLpt) framework is used to calculate the thermodynamic functions of a quark-gluon plasma to three-loop order. This is the highest order accessible by finite temperature perturbation theory applied…

High Energy Physics - Phenomenology · Physics 2015-03-19 Jens O. Andersen , Lars E. Leganger , Michael Strickland , Nan Su

We calculate the two-loop heavy quarkonium Hamiltonian within potential-NRQCD effective field theory in the non-annihilation channel. This calculation represents the first non-trivial step towards determining the N$^4$LO Hamiltonian in the…

High Energy Physics - Phenomenology · Physics 2024-11-15 Go Mishima , Yukinari Sumino , Hiromasa Takaura

We determine the 2-loop effective gauge coupling of QCD at high temperatures, defined as a matching coefficient appearing in the dimensionally reduced effective field theory. The result allows to improve on one of the classic…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Laine , Y. Schroder

We review the various methods which have been employed recently to describe the thermodynamics of the high temperature quark-gluon plasma using weak coupling techniques, and we compare their results with those of most recent lattice gauge…

High Energy Physics - Phenomenology · Physics 2016-11-23 J. -P. Blaizot , E. Iancu , A. Rebhan

In this paper, we compute the constrained QCD effective potential up to two-loop order with finite quark mass and chemical potential. We present the explicit calculations by using the double line notation and analytical expressions for…

High Energy Physics - Phenomenology · Physics 2019-05-14 Yun Guo , Qianqian Du

Making use of conformal symmetry of large-$n_f$ QCD in $d=4-2\epsilon$ dimensions at the Wilson-Fischer fixed point, we calculate the two-loop coefficient functions in the operator product expansion of two electromagnetic currents in…

High Energy Physics - Phenomenology · Physics 2024-11-25 Vladimir M. Braun , Hua-Yu Jiang , Alexander N. Manashov , Andreas von Manteuffel

The Hard Thermal Loop expansion, is an attractive theory, but it reveals difficulties when one uses it as a perturbative scheme. To illustrate this we use the HTL expansion to calculate the two loop corrections for soft virtual photons. The…

High Energy Physics - Phenomenology · Physics 2007-05-23 Haitham Zaraket

We extend a previous investigation of the QCD phase diagram with heavy quarks in the context of background field methods by including the two-loop corrections to the background field effective potential. The nonperturbative dynamics in the…

High Energy Physics - Phenomenology · Physics 2018-05-02 J. Maelger , U. Reinosa , J. Serreau

We compare our previously proposed hard-thermal-loop (HTL) resummed calculation of quark number susceptibilities using a self-consistent two-loop approximation to the quark density with a recent calculation of the same quantity at the…

High Energy Physics - Phenomenology · Physics 2011-09-13 J. -P. Blaizot , E. Iancu , A. Rebhan

Within the framework of the hard thermal loop effective theory we derive a system of Boltzmann-like kinetic equations taking into account the simplest processes of nonlinear interaction of soft fermionic and bosonic QCD plasma excitations:…

High Energy Physics - Phenomenology · Physics 2007-05-23 Yu. A. Markov , M. A. Markova