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Related papers: Analytic QCD Flavor Thresholds Through Two Loops

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The quarkonic contributions to the three-loop heavy-quark form factors for vector, axial-vector, scalar and pseudoscalar currents are described by closed form difference equations for the expansion coefficients in the limit of small…

High Energy Physics - Phenomenology · Physics 2023-07-07 Johannes Blümlein , Abilio De Freitas , Peter Marquard , Narayan Rana , Carsten Schneider

We calculate the full set of the two-loop master integrals for heavy-to-light form factors of two different massive fermions for arbitrary momentum transfer in NNLO QCD or QED corrections. These integrals allow to determine the two-loop QCD…

High Energy Physics - Phenomenology · Physics 2018-04-04 Long-Bin Chen

We explain how the strategy of solving renormalization problems in HQET non-perturbatively by a matching to QCD in finite volume can be implemented to include dynamical fermions. As a primary application, some elements of an HQET…

High Energy Physics - Lattice · Physics 2008-11-26 Michele Della Morte , Patrick Fritzsch , Jochen Heitger , Harvey B. Meyer , Hubert Simma , Rainer Sommer

Starting at 3-loop order, the massive Wilson coefficients for deep-inelastic scattering and the massive operator matrix elements describing the variable flavor number scheme receive contributions of Feynman diagrams carrying quark lines…

High Energy Physics - Phenomenology · Physics 2017-08-23 J. Ablinger , J. Blümlein , A. De Freitas , A. Hasselhuhn , C. Schneider , F. Wißbrock

During the last year, analytic expressions for the two-loop QCD corrections to the form factors for the vector, axial-vector, scalar and pseudo-scalar vertices involving a pair of heavy quarks, $Q \bar{Q}$, were calculated. The results are…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. Bernreuther , R. Bonciani , T. Gehrmann , R. Heinesch , T. Leineweber , P. Mastrolia , E. Remiddi

We non-perturbatively determine the renormalization constant and the improvement coefficients relating the renormalized current and subtracted quark mass in O(a) improved two-flavour lattice QCD. We employ the Schr\"odinger functional…

High Energy Physics - Lattice · Physics 2010-10-06 Patrick Fritzsch , Jochen Heitger , Nazario Tantalo

We present closed analytic expressions of the electromagnetic vertex form factors for heavy quarks at the two-loop level in QCD for arbitrary momentum transfer. The calculation is carried out in dimensional regularization. The electric and…

High Energy Physics - Phenomenology · Physics 2010-04-05 W. Bernreuther , R. Bonciani , T. Gehrmann , R. Heinesch , T. Leineweber , P. Mastrolia , E. Remiddi

We present results of a simulation of 2 flavour QCD on a $16^3\times4$ lattice using p4-improved staggered fermions with bare quark mass $m/T=0.4$. Derivatives of the thermodynamic grand canonical partition function $Z(V,T,\mu_u,\mu_d)$…

High Energy Physics - Phenomenology · Physics 2016-08-16 S. Ejiri , C. R. Allton , M. Döring , S. J. Hands , O. Kaczmarek , F. Karsch , E. Laermann , K. Redlich

We perform numerical simulations of lattice QCD with two flavors of dynamical overlap quarks, which have exact chiral symmetry on the lattice. While this fermion discretization is computationally demanding, we demonstrate the feasibility to…

The results of calculation of the three-loop radiative correction to the renormalization constant of fermion masses for non-abelian gauge theory interacting with fermions are presented. Dimensional regularization and the 't Hooft minimal…

High Energy Physics - Phenomenology · Physics 2020-04-22 O. V. Tarasov

We investigate the properties of the half-filling point in lattice QCD (LQCD), in particular the disappearance of the sign problem and the emergence of an apparent particle-hole symmetry, and try to understand where these properties come…

High Energy Physics - Lattice · Physics 2016-02-22 Tobias Rindlisbacher , Philippe de Forcrand

We calculate the critical value of the hopping parameter, $\kappa_c$, in Lattice QCD, up to two loops in perturbation theory. We employ the Sheikholeslami-Wohlert (clover) improved action for fermions and the Symanzik improved gluon action…

High Energy Physics - Lattice · Physics 2008-11-26 A. Skouroupathis , M. Constantinou , H. Panagopoulos

In this paper we consider the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order in perturbation theory. We evaluate the fermionic corrections containing a…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Marquard , J. H. Piclum , D. Seidel , M. Steinhauser

QCD with heavy dynamical quarks exhibits a first order thermal transition which is driven by the spontaneous breaking of the global $\mathcal{Z}_3$ center symmetry. Decreasing the quark masses weakens the transition until the corresponding…

High Energy Physics - Lattice · Physics 2021-12-09 Ruben Kara , Szabolcs Borsanyi , Zoltan Fodor , Jana N. Guenther , Paolo Parotto , Attila Pasztor , Denes Sexty

The global center symmetry of quenched QCD at zero baryonic chemical potential is broken spontaneously at a critical temperature $T_c$ leading to a first-order phase transition. Including heavy dynamical quarks breaks the center symmetry…

High Energy Physics - Lattice · Physics 2023-08-08 Reinhold Kaiser , Owe Philipsen

The order and the nature of the finite-temperature phase transition of QCD with two flavors of dynamical quarks is investigated. An analysis of the critical exponent of the specific heat is performed through finite-size and finite-mass…

High Energy Physics - Lattice · Physics 2008-11-26 J. M. Carmona , M. D'Elia , L. Del Debbio , A. Di Giacomo , B. Lucini , G. Paffuti , C. Pica

For quantifying the universal properties of the chiral phase transition in QCD through numerical calculations on a discrete space-time lattice, one needs to perform controlled extrapolations to the continuum and infinite-volume limits…

High Energy Physics - Lattice · Physics 2025-08-28 Sabarnya Mitra , Frithjof Karsch

We present a complete set of analytic helicity amplitudes for top quark pair production via gluon fusion at two-loops in QCD. For the first time, we include corrections due to massive fermion loops which give rise to integrals over elliptic…

High Energy Physics - Phenomenology · Physics 2021-07-14 Simon Badger , Ekta Chaubey , Heribertus Bayu Hartanto , Robin Marzucca

We demonstrate the applicability of a recently proposed multiscale thermalization algorithm to two-color quantum chromodynamics (QCD) with two mass-degenerate fermion flavors. The algorithm involves refining an ensemble of gauge…

High Energy Physics - Lattice · Physics 2016-12-06 William Detmold , Michael G. Endres

Flavor mixing is scrutinized at 1-loop in a SU(2)_L gauge theory of massive fermions. The main issue is to cope with kinetic-like, momentum (p^2) dependent effective interactions that arise at this order. They spoil the unitarity of the…

High Energy Physics - Phenomenology · Physics 2010-06-16 Bruno Machet