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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 present new contributions to the decay matrix element $\Gamma_{12}^q$ of the $B_q$-$\bar B_q$ mixing complex, where $q=d$ or $s$. Our new results constitute the order $\alpha_s^2 N_f$ corrections to the penguin contributions to the…

High Energy Physics - Phenomenology · Physics 2020-09-09 Hrachia M. Asatrian , Hrachya H. Asatryan , Artyom Hovhannisyan , Ulrich Nierste , Sergey Tumasyan , Arsen Yeghiazaryan

We compute next-to-next-to-leading order corrections to the decay width difference of mass eigenstates and the charge-parity (CP) asymmetry $a_{\rm fs}$ in flavour-specific decays of neutral $B$ mesons. We include both current-current and…

High Energy Physics - Phenomenology · Physics 2026-04-01 Ulrich Nierste , Pascal Reeck , Vladyslav Shtabovenko , Matthias Steinhauser

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 use the heavy quark expansion to investigate the width difference $\Delta\Gamma_{B_s}$ between the $B_s$ mass eigenstates. The corrections of ${\cal O}(\Lambda_{QCD}/m_b)$ and ${\cal O}(m_s/m_b)$ to the leading order expression in the…

High Energy Physics - Phenomenology · Physics 2011-07-04 M. Beneke , G. Buchalla , I. Dunietz

We extend the theoretical prediction for the width difference $\Delta \Gamma_q$ in the mixing of neutral $B$ mesons in the Standard Model to next-to-next-to-leading order in $\alpha_s$. To this aim we calculate three-loop diagrams with two…

High Energy Physics - Phenomenology · Physics 2022-09-14 Marvin Gerlach , Ulrich Nierste , Vladyslav Shtabovenko , Matthias Steinhauser

We update the theory predictions for the mass difference $\dm_s$, the width difference $\dg_s$ and the CP asymmetry in flavour-specific decays, $a_{\rm fs}^{s}$, for the \bbs system. In particular we present a new expression for the element…

High Energy Physics - Phenomenology · Physics 2010-10-27 Alexander Lenz , Ulrich Nierste

We calculate the three-loop master integrals of Ref. [1] [arXiv:1709.02160] in analytic form. This allows us to present the fermionic contributions to the $\Delta B=2$ Wilson coefficients of the $B$-$\bar B$ decay matrix in…

High Energy Physics - Phenomenology · Physics 2022-07-06 Artyom Hovhannisyan , Ulrich Nierste

Starting from the most general effective $|\Delta B| = 1$ Hamiltonian describing non-leptonic $b$-quark decays $b\to q_1 \bar q_2 q_3$, we compute analytic expressions for all matching coefficients of the two-quark operator contributions in…

High Energy Physics - Phenomenology · Physics 2026-05-27 Martin Lang , Alexander Lenz , Ali Mohamed , Maria Laura Piscopo , Aleksey V. Rusov

We compute the matrix element of the four-quark operator $\Op_S$ = $\bar{b}(1-\gamma_5) s \bar{b} (1-\gamma_5) s$ in the $B_s-\bar{B}_s$ mixing on the lattice using NRQCD, which gives a leading contribution in the calculation of the width…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Hashimoto , K-I. Ishikawa , T. Onogi , N. Yamada

We compute the QCD corrections to the decay rate difference in the $B_s-\bar B_s$ system, $\Delta\Gamma_{B_s}$, in the next-to-leading logarithmic approximation using the heavy quark expansion approach. Going beyond leading order in QCD is…

High Energy Physics - Phenomenology · Physics 2009-10-09 M. Beneke , G. Buchalla , C. Greub , A. Lenz , U. Nierste

We revisit the Next-to-Leading Order (two-loop) contributions to the Anomalous Dimensions of $\Delta F = 1$ four-quark operators in QCD. We devise a test for anomalous dimensions, that we regard as of general interest, and by means of which…

High Energy Physics - Phenomenology · Physics 2025-06-19 Pol Morell , Javier Virto

New physics contributions to B decays often arise through chromo-magnetic penguin operators. To look for new physics effects in B decays, it is useful to be able to estimate the hadronic matrix elements for the chromo-magnetic operator. We…

High Energy Physics - Phenomenology · Physics 2009-11-10 Satoshi Mishima , A. I. Sanda

Predicting the $B_s^0-\bar{B}_s^0$ width difference $\Delta\Gamma_s$ relies on the heavy quark expansion and on hadronic matrix elements of $\Delta B=2$ operators. We present the first lattice QCD results for matrix elements of the…

High Energy Physics - Lattice · Physics 2020-02-27 Christine T. H. Davies , Judd Harrison , G. Peter Lepage , Christopher J. Monahan , Junko Shigemitsu , Matthew Wingate

We discuss the calculation of the width difference $\Delta\Gamma_{B_s}$ between the $B_s$ mass eigenstates to next-to-leading order in the heavy quark expansion. $1/m_b$-corrections are estimated to reduce the leading order result by…

High Energy Physics - Phenomenology · Physics 2016-09-06 M. Beneke

We present lattice QCD results for the matrix elements of $R_2$ and other dimension-7, $\Delta B = 2$ operators relevant for calculations of $\Delta \Gamma_s$, the $B_s-\bar{B}_s$ width difference. We have computed correlation functions…

High Energy Physics - Lattice · Physics 2018-03-29 Christine Davies , Judd Harrison , G Peter Lepage , Christopher Monahan , Junko Shigemitsu , Matthew Wingate

We compute next-to-next-to-leading order perturbative corrections to the decay width difference of mass eigenstates and the charge-parity asymmetry $a_{\rm fs}$ in flavour-specific decays of neutral $B$ mesons. In our calculation we take…

High Energy Physics - Phenomenology · Physics 2025-05-30 Marvin Gerlach , Ulrich Nierste , Pascal Reeck , Vladyslav Shtabovenko , Matthias Steinhauser

Penguin diagrams for decays such as $b\to (s,d)\gamma$ involve virtual loops of $u$ or other light quarks. Logarithms of the virtual quark mass could, in principle, influence the phenomenological analysis of the decay. It is thus important…

High Energy Physics - Phenomenology · Physics 2014-11-17 Mario Abud , Giulia Ricciardi , George Sterman

We complete the calculation of the QCD penguin amplitude at next-to-next-to-leading order in the QCD factorization approach to non-leptonic B-meson decays. This provides the last missing piece in the computation of the QCD correction to…

High Energy Physics - Phenomenology · Physics 2020-05-20 Guido Bell , Martin Beneke , Tobias Huber , Xin-Qiang Li

We include two loop, relativistic one loop and second order relativistic tree level corrections, plus leading nonperturbative contributions, to obtain a calculation of the lower states in the heavy quarkonium spectrum correct up to, and…

High Energy Physics - Phenomenology · Physics 2011-01-27 A. Pineda , F. J. Yndurain
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