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We investigate the effects of including the full three-loop QCD correction to the static short distance $1/r$ potential on the spectroscopy and decays in the charmonium and upsilon systems. We use a variational technique with the full…

High Energy Physics - Phenomenology · Physics 2013-08-28 Wayne W. Repko , Marco D. Santia , Stanley F. Radford

In this paper we evaluate the renormalization constants and anomalous dimensions for the squark wave function and mass within supersymmetric QCD. These results complement the ones obtained in Ref. \cite{Harlander:2009mn} and thus provide…

High Energy Physics - Phenomenology · Physics 2015-05-28 Thomas Hermann , Luminita Mihaila , Matthias Steinhauser

We present the three-loop QCD+QED mixed corrections to the on-shell quark mass and wave-function renormalization constants through orders $\mathcal{O}(\alpha_s^m\alpha^n)$ with $m+n=3$. We further derive the three-loop relation between the…

High Energy Physics - Phenomenology · Physics 2026-02-24 Long Chen , Hong-Yang Han , Zhe Li , Marco Niggetiedt

We compute corrections of order $\alpha_s^3$ to the decay $b \to c \ell \bar\nu$ taking into account massive charm quarks. In the on-shell scheme large three-loop corrections are found. However, in the kinetic scheme the three-loop…

High Energy Physics - Phenomenology · Physics 2021-07-16 Matteo Fael , Kay Schönwald , Matthias Steinhauser

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 compute the $\alpha_s^2 n_f$ perturbative QCD contribution to semileptonic B decay, including the finite mass of the charm quark. This result provides an estimate of the size of the two-loop correction, which is found to be about 50\% of…

High Energy Physics - Phenomenology · Physics 2011-01-25 Michael Luke , Martin J. Savage , Mark B. Wise

Dimensional Reduction is applied to \qcd{} in order to compute various renormalization constants in the \drbar{} scheme at higher orders in perturbation theory. In particular, the $\beta$ function and the anomalous dimension of the quark…

High Energy Physics - Phenomenology · Physics 2009-11-11 R. Harlander , P. Kant , L. Mihaila , M. Steinhauser

We present the first analytic results of N$^3$LO QCD corrections to the top-quark decay width. We focus on the dominant leading color contribution, which includes light-quark loops. At NNLO, this dominant contribution accounts for 95% of…

High Energy Physics - Phenomenology · Physics 2024-04-26 Long-Bin Chen , Hai Tao Li , Zhao Li , Jian Wang , Yefan Wang , Quan-feng Wu

The three-loop non-mixing contributions to the anomalous dimension of the leading order quark pair production current in non-relativistic QCD are computed. It is demonstrated that the renormalization procedure can only be carried out…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. H. Hoang

We evaluate the three-loop corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and non-relativistic QCD. The result is presented in the MSbar scheme where large perturbative corrections are…

High Energy Physics - Phenomenology · Physics 2014-03-05 Peter Marquard , Jan H. Piclum , Dirk Seidel , Matthias Steinhauser

We give a review and present a comprehensive calculation for the leptonic constant B_{c} of the low-lying pseudoscalar and vector states of B_{c}-meson in the framework of static and QCD-motivated nonrelativistic potential models taking…

High Energy Physics - Phenomenology · Physics 2008-11-26 Sameer M. Ikhdair , Ramazan Sever

We present an analytic expression for the two-loop QCD corrections to the decay process b -> u W^*, where b and u are a massive and massless quark, respectively, while W^* is an off-shell charged weak boson. Since the W-boson can…

High Energy Physics - Phenomenology · Physics 2011-01-27 R. Bonciani , A. Ferroglia

We calculate the semileptonic branching ratio and the charm counting of inclusive $B$ meson decays using the perturbative QCD formalism. For the nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients…

High Energy Physics - Phenomenology · Physics 2011-01-25 Chia-Hung V. Chang , Darwin Chang , We-Fu Chang , Hsiang-nan Li , Hoi-Lai Yu

We consider the currents formed by a heavy and a light quark within Quantum Chromodynamics and compute the matching to Heavy Quark Effective Theory to three-loop accuracy. As an application we obtain the third-order perturbative corrections…

High Energy Physics - Phenomenology · Physics 2010-04-30 S. Bekavac , A. G. Grozin , P. Marquard , J. H. Piclum , D. Seidel , M. Steinhauser

We calculate the leptonic constant for the ground pseudoscalar state of B_c meson in the framework of QCD-motivated potential model taking into account the two-loop anomalous dimension for the heavy quark current in the nonrelativistic QCD…

High Energy Physics - Phenomenology · Physics 2011-03-23 V. V. Kiselev

We present an analysis of two-loop mixed QCD and electroweak corrections to the decay of the Z boson into light quarks. We find that the naive factorization of QCD and electroweak corrections does not describe correctly the two-loop…

High Energy Physics - Phenomenology · Physics 2009-10-28 Andrzej Czarnecki , Johann H. Kühn

We compute the matching coefficients between QCD and non-relativistic QCD for external vector, axial-vector, scalar and pseudo-scalar currents up to three-loop order. We concentrate on the non-singlet contributions and present precise…

High Energy Physics - Phenomenology · Physics 2022-06-22 Manuel Egner , Matteo Fael , Fabian Lange , Kay Schönwald , Matthias Steinhauser

We compute the four-loop QCD corrections to the massless quark-anti-quark-photon form factor $F_q$ in the large-$N_c$ limit. From the pole part we extract analytic expressions for the corresponding cusp and collinear anomalous dimensions.

High Energy Physics - Phenomenology · Physics 2017-04-26 Johannes Henn , Roman N. Lee , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We compute the on-shell wave function renormalization constant to four-loop order in QCD and present numerical results for all coefficients of the SU$(N_c)$ colour factors. We extract the four-loop HQET anomalous dimension of the heavy…

High Energy Physics - Phenomenology · Physics 2018-04-04 Peter Marquard , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We compute the decay constants of the pseudoscalar mesons D and D_{s} using a linear combination of finite energy sum rules which minimize the contribution of the unknown continuum spectral function. We employ the recent three loop…

High Energy Physics - Phenomenology · Physics 2016-08-16 J. Bordes , J. Peñarrocha , K. Schilcher