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We compute the three-loop QCD corrections to the decoupling constant for $\alpha_s$ which relates the Minimal Supersymmetric Standard Model to Quantum Chromodynamics with five or six active flavours. The new results can be used to study the…

High Energy Physics - Phenomenology · Physics 2017-08-23 Alexander Kurz , Matthias Steinhauser , Nikolai Zerf

The two--loop mechanism of Bjorken and Weinberg is used to constrain flavor changing neutral Higgs bosons. We calculate the complete set of two--loop diagrams for the rare decay $\mu \rightarrow e + \gamma$ induced by such neutral Higgs…

High Energy Physics - Phenomenology · Physics 2009-09-01 D. Chang , W. -S Hou , W. -Y. Keung

We compute the matching coefficient between the quantum chromodynamics (QCD) and the non-relativistic QCD ( NRQCD) for the flavor-changing scalar current involving the heavy charm and bottom quark, up to the three-loop order within the…

High Energy Physics - Phenomenology · Physics 2023-05-03 Wei Tao , Ruilin Zhu , Zhen-Jun Xiao

QCD in non-integer d=4-2 epsilon space-time dimensions possesses a nontrivial critical point and enjoys exact scale and conformal invariance. This symmetry imposes nontrivial restrictions on the form of the renormalization group equations…

High Energy Physics - Phenomenology · Physics 2015-06-19 V. M. Braun , A. N. Manashov

QCD evolution equations in minimal subtraction schemes have a hidden symmetry: One can construct three operators that commute with the evolution kernel and form an $SL(2)$ algebra, i.e. they satisfy (exactly) the $SL(2)$ commutation…

High Energy Physics - Phenomenology · Physics 2016-04-20 V. M. Braun , A. N. Manashov , S. Moch , M. Strohmaier

The precise measurement of the width difference \Delta\Gamma_s among the mass eigenstates of the B_s-\bar{B}_s system requires the calculation of the corresponding decay matrix to order \alpha_s/m_b. QCD corrections to power-suppressed…

High Energy Physics - Phenomenology · Physics 2026-04-01 Artyom Hovhannisyan , Ulrich Nierste

We compute the branching ratios for the rare top quark decays t to c gamma and t to c Z mediated by effective flavor changing neutral couplings at the next-to-leading order in QCD including the effects due to operator mixing. After…

High Energy Physics - Phenomenology · Physics 2014-11-20 Jure Drobnak , Svjetlana Fajfer , Jernej F. Kamenik

The renormalization of the scalar diquark operator and its anomalous dimension is calculated at two-loop order in QCD, enabling higher-order QCD studies of diquarks. As an application of our result, the two-loop diquark anomalous dimension…

High Energy Physics - Phenomenology · Physics 2011-11-30 R. T. Kleiv , T. G. Steele

The decay B_s -> mu^+ mu^- in the Standard Model is generated by the well-known W-box and Z-penguin diagrams that give rise to an effective quark-lepton operator Q_A at low energies. We compute QCD corrections of order alpha_s^2 to its…

High Energy Physics - Phenomenology · Physics 2014-03-18 Thomas Hermann , Mikolaj Misiak , Matthias Steinhauser

We report on the two-loop amplitude computation for the mixed QCD-electroweak corrections to the process $gg \to Hg$, with exact dependence on the electroweak boson masses. This amplitude has been employed in the computation of…

High Energy Physics - Phenomenology · Physics 2022-05-11 Matteo Becchetti , Francesco Moriello , Armin Schweitzer

We report on recent results on the two-mass corrections for massive operator matrix elements at 2- and 3-loop orders in QCD. These corrections form the building blocks of the variable flavor number scheme. Due to the similar values of the…

High Energy Physics - Phenomenology · Physics 2018-07-23 J. Ablinger , J. Blümlein , A. De Freitas , A. Goedicke , C. Schneider , K. Schönwald

I consider neutron electric dipole moment contributions induced by flavor changing Standard Model Higgs boson couplings to quarks. Such couplings might stem from non-renormalizable $SU(2)_L \times U(1)_Y$ invariant Lagrange terms of…

High Energy Physics - Phenomenology · Physics 2018-03-13 Jan O. Eeg

We consider two-loop QCD corrections to the element $\Gamma_{12}^q$ of the decay matrix in $B_q-\bar{B}_q$ mixing, $q=d,s$, in the leading power of the Heavy Quark Expansion. The calculated contributions involve one current-current and one…

High Energy Physics - Phenomenology · Physics 2021-07-28 Marvin Gerlach , Ulrich Nierste , Vladyslav Shtabovenko , Matthias Steinhauser

We compute the two-loop QCD helicity amplitudes for the production of a Higgs boson in association with a bottom-quark pair at a hadron collider. We take the approximations of leading colour and work in the five flavour scheme, where the…

High Energy Physics - Phenomenology · Physics 2021-11-24 Simon Badger , Heribertus Bayu Hartanto , Jakub Kryś , Simone Zoia

We report on the complete three-loop corrections to the Higgs-gluon form factor in QCD. While previous calculations are based on QCD with a single heavy quark of arbitrary mass, we extend the study to QCD involving two different massive…

High Energy Physics - Phenomenology · Physics 2024-02-28 Marco Niggetiedt , Johann Usovitsch

We study flavor changing neutral current decays of the top quark in the context of general warped extra dimensions, where the five dimensional metric is slightly modified from 5D anti-de-Sitter (AdS$_5$). These models address the…

High Energy Physics - Phenomenology · Physics 2016-08-10 Alfonso Diaz-Furlong , Mariana Frank , Nima Pourtolami , Manuel Toharia , Reyna Xoxocotzi

In QCD the anomalous dimensions of gauge invariant operators of twist 2 play a key role, because they control the scale dependence of the parton distribution functions. Notably, the flavour singlet operators, such as those associated to the…

High Energy Physics - Phenomenology · Physics 2022-07-21 Giulio Falcioni

The resummation of soft gluon exchange for QCD hard scattering requires a matrix of anomalous dimensions. We compute this matrix directly for arbitrary 2 to n massless processes for the first time at two loops. Using color generator…

High Energy Physics - Phenomenology · Physics 2009-04-06 S. Mert Aybat , Lance J. Dixon , George Sterman

QCD in non-integer $d=4-2\epsilon$ space-time dimensions enjoys conformal invariance at the special fine-tuned value of the coupling. Counterterms for composite operators in minimal subtraction schemes do not depend on $\epsilon$ by…

High Energy Physics - Phenomenology · Physics 2019-03-27 V. M. Braun , A. N. Manashov , S. Moch , M. Strohmaier

We present the analytic calculation of the two-loop QCD corrections to the decay width of a Higgs boson into a photon and a $Z$ boson. The calculation is carried out using integration-by-parts identities for the reduction to master…

High Energy Physics - Phenomenology · Physics 2015-09-30 R. Bonciani , V. Del Duca , H. Frellesvig , J. M. Henn , F. Moriello , V. A. Smirnov