Two- and three-loop QCD corrections to the width difference in the Bs−BˉsB_s - \bar{B}_s system

We report on a series of two- and three-loop calculations that were necessary to improve the theory prediction for the width difference \Delta\Gamma_ in the $B_s - \bar{B}_s$ mixing. For the first time we are able to predict this important flavor observable at NNLO accuracy, which is necessary to approach the current experimental precision. Our new Standard-Model prediction obtained from the average of calculations done in the $\bar{MS}$ and potential subtracted (PS) schemes reads \Delta\Gamma_ = (0.076 ± 0.017) ps$^{−1}$

FeynCalc 9.3: New features and improvements

We present FeynCalc 9.3, a new stable version of a powerful and versatile Mathematica package for symbolic quantum field theory (QFT) calculations. Some interesting new features such as highly improved interoperability with other packages, automatic extraction of the ultraviolet divergent parts of 1-loop integrals, support for amplitudes with Majorana fermions and γ-matrices with explicit Dirac indices are explained in detail. Furthermore, we discuss some common problems and misunderstandings that may arise in the daily usage of the package, providing explanations and workarounds

FeynCalc 9.3: New features and improvements

We present FeynCalc 9.3, a new stable version of a powerful and versatile Mathematica package for symbolic quantum field theory (QFT) calculations. Some interesting new features such as highly improved interoperability with other packages, automatic extraction of the ultraviolet divergent parts of 1-loop integrals, support for amplitudes with Majorana fermions and γ-matrices with explicit Dirac indices are explained in detail. Furthermore, we discuss some common problems and misunderstandings that may arise in the daily usage of the package, providing explanations and workarounds

FeynHelpers: Connecting FeynCalc to FIRE and Package-X

We present a new interface called FeynHelpers that connects FeynCalc, a Mathematica package for symbolic semi-automatic evaluation of Feynman diagrams and calculations in quantum field theory (QFT) to Package-X and FIRE. The former provides a library of analytic results for scalar 1-loop integrals with up to 4 legs, while the latter is a general-purpose tool for reduction of multi-loop scalar integrals using Integration-by-Parts (IBP) identities

New developments in FeynCalc 9.0

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract In this note we report on the new version of FeynCalc, a Mathematica package for symbolic semi-automatic evaluation of Feynman diagrams and algebraic expressions in quantum field theory. The main features of version 9.0 are: improved tensor reduction and partial fractioning of loop integrals, new functions for using FeynCalc together with tools for reduction of scalar loop integrals using integration-by-parts (IBP) identities, better interface to FeynArts and support for S U ( N ) generators ... Title of program: FeynCalc Catalogue Id: AFBB_v1_0 Nature of problem Symbolic semi-automatic evaluation of Feynman diagrams and algebraic expressions in quantum field theory. Versions of this program held in the CPC repository in Mendeley Data AFBB_v1_0; FeynCalc; 10.1016/j.cpc.2016.06.00

New Developments in FeynCalc 9.0

In this note we report on the new version of FeynCalc, a Mathematica package for symbolic semi-automatic evaluation of Feynman diagrams and algebraic expressions in quantum field theory. The main features of version 9.0 are: improved tensor reduction and partial fractioning of loop integrals, new functions for using FeynCalc together with tools for reduction of scalar loop integrals using integration-by-parts (IBP) identities, better interface to FeynArts and support for SU(N) generators with explicit fundamental indices

Relativistic corrections to electromagnetic heavy quarkonium production

We report on the calculation [1] of the relativistic O(αs0 ν2) corrections to the quarkonium production process e+e− → χcJ + γ in non-relativistic QCD (NRQCD). In our work we incorporate effects from operators that contribute through the sub-leading Fock state |QQ̄g〉, that were not taken into account by previous studies. We determine the corresponding matching coeffcients that should be included into theoretical predictions for the electromagnetic production cross-section of χcJ. This process could be, in principle, measured by the Belle II experiment