English
Related papers

Related papers: Analytic two-loop virtual corrections to $b --> d …

200 papers

We compute the QCD corrections at next-to-leading order for the process $gg \rightarrow ZH$, including both the virtual two-loop terms and real-emission contributions. The two-loop box diagrams in the virtual corrections are approximated…

High Energy Physics - Phenomenology · Physics 2022-08-24 Giuseppe Degrassi , Ramona Gröber , Marco Vitti , Xiaoran Zhao

We compute the part of the two-loop virtual amplitude for the process $gg \to V_1 V_2 \to (l_1 \bar l'_{1}) (l_2 \bar l'_2)$, where $V_{1,2}$ are arbitrary electroweak gauge bosons, that receives contributions from loops of massless quarks.…

High Energy Physics - Phenomenology · Physics 2015-04-02 Fabrizio Caola , Johannes M. Henn , Kirill Melnikov , Alexander V. Smirnov , Vladimir A. Smirnov

We compute the two-loop master integrals for non-leptonic heavy-to-heavy decays analytically in a recently-proposed canonical basis. For this genuine two-loop, two-scale problem we first derive a basis for the master integrals that…

High Energy Physics - Phenomenology · Physics 2015-05-20 Tobias Huber , Susanne Krankl

Multi-loop integrals can be evaluated numerically using Mellin-Barnes representations. Here this technique is applied to the calculation of electroweak two-loop correction with closed fermion loops for two observables: the effective weak…

High Energy Physics - Phenomenology · Physics 2013-10-14 A. Freitas , Yi-Cheng Huang

We investigate the radiative quantum electrodynamic (QED) corrections to the lepton ($L=e, ~\mu $ and $\tau$) anomalous magnetic moment due to the contributions of diagrams with insertions of the photon vacuum polarisation operator…

High Energy Physics - Phenomenology · Physics 2023-10-19 O. P. Solovtsova , V. I. Lashkevich , L. P. Kaptari

We give some details of the recently completed calculation of the full two-loop fermionic corrections to the effective leptonic weak mixing angle. Among others, we describe the C++ library DiaGen/IdSolver, which was used to reduce the…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Awramik , M. Czakon , A. Freitas , G. Weiglein

We consider QCD radiative corrections to $W^+W^-b {\bar b}$ production with leptonic decays and massive bottom quarks at the LHC. We perform an exact next-to-leading order (NLO) calculation within the $q_T$-subtraction formalism and…

High Energy Physics - Phenomenology · Physics 2025-07-17 Luca Buonocore , Massimiliano Grazzini , Stefan Kallweit , Jonas M. Lindert , Chiara Savoini

We calculate the one- and two-loop corrections of order alpha(Zalpha)^6 and alpha^2(Zalpha)^6 respectively, to the Lamb shift in hydrogen-like systems using the formalism of nonrelativistic quantum electrodynamics. We obtain general results…

Atomic Physics · Physics 2009-11-11 Ulrich D. Jentschura , Andrzej Czarnecki , Krzysztof Pachucki

We compute the two-loop corrections to the massless quark form factor $\gamma^* \to q\bar q$ and gluon form factor $H\to gg$ to all orders in the dimensional regularisation parameter $\epsilon=(4-d)/2$. The two-loop contributions to the…

High Energy Physics - Phenomenology · Physics 2021-11-04 T. Gehrmann , T. Huber , D. Maitre

We compute the next-to-next-to-leading order (NNLO) QCD corrections to b \to c l \bar \nu_l decay rate at a fully differential level. Arbitrary cuts on kinematic variables of the decay products can be imposed. Our computation can be used to…

High Energy Physics - Phenomenology · Physics 2014-11-18 Kirill Melnikov

We present the analytic evaluation of the second-order corrections to the massive form factors, due to two-loop vertex diagrams with a vacuum polarization insertion, with exact dependence on the external and internal fermion masses, and on…

High Energy Physics - Phenomenology · Physics 2024-01-24 Taushif Ahmed , Giulio Crisanti , Federico Gasparotto , Syed Mehedi Hasan , Pierpaolo Mastrolia

I overview the hadronic input for the exclusive flavour-changing neutral-current $B$-decays with a vector ($V=K^*,\rho$) or pseudoscalar ($P=K,\pi$) meson in the final state. After presenting the current status of $B\to P,V$ form factors, I…

High Energy Physics - Phenomenology · Physics 2015-03-17 Alexander Khodjamirian

We present a determination of a new class of three-loop Feynman diagrams describing heavy-to-light transitions. We apply it to find the O(alpha_s^2) corrections to the top quark decay t -> bW and to the distribution of lepton invariant mass…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ian Blokland , Andrzej Czarnecki , Maciej Slusarczyk , Fyodor Tkachov

Leptoquarks (LQs) provide very promising solutions to the tensions between the experimental measurements and the SM predictions of $b\to s\ell^+\ell^-$ and $b\to c\tau\nu$ processes. In this case the LQ masses are in general at the TeV…

High Energy Physics - Phenomenology · Physics 2019-03-13 Jason Aebischer , Andreas Crivellin , Christoph Greub

We present the QCD radiative corrections to the full off-shell $\rm t\bar{t}W^+$ production, considering a final state with three charged leptons, two b jets and missing energy. All interferences, off-shell effects and spin correlations are…

High Energy Physics - Phenomenology · Physics 2020-12-16 Ansgar Denner , Giovanni Pelliccioli

The soft current describes the factorization behavior of quantum chromodynamics (QCD) scattering amplitudes in the limit of vanishing energy of one of the external partons. It is process-independent and can be expanded in a perturbative…

High Energy Physics - Phenomenology · Physics 2015-06-17 Claude Duhr , Thomas Gehrmann

We compute the NNLO QCD corrections for the hadroproduction of a pair of off-shell photons in the limit of a large number of quark flavors. We perform a reduction of the two-loop amplitude to master integrals and calculate the latter…

High Energy Physics - Phenomenology · Physics 2015-06-22 Charalampos Anastasiou , Julian Cancino , Federico Chavez , Claude Duhr , Achilleas Lazopoulos , Bernhard Mistlberger , Romain Mueller

We present the electroweak corrections for the production of a photon pair through gluon fusion, focusing on the contribution from the first two generations of quarks. The two-loop amplitude is calculated using a series of projection…

High Energy Physics - Phenomenology · Physics 2025-12-09 Gabriele Fiore , Ciaran Williams

We compute the two-loop massless QCD corrections to the helicity amplitudes for the production of two electroweak gauge bosons in the gluon fusion channel, $gg \to V_1 V_2$, keeping the virtuality of the vector bosons $V_1$ and $V_2$…

High Energy Physics - Phenomenology · Physics 2015-09-14 Andreas von Manteuffel , Lorenzo Tancredi

In this contribution three-loop QCD corrections to current correlators are considered. The application of the large momentum procedure, which provides a systematic expansion in $(m^2/q^2)^n$, allows the computation of terms up to $n=6$ for…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Steinhauser