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Related papers: The $B_K$ Parameter in the $1/N_c$ Expansion

200 papers

We report updated results for $B_K$ calculated using HYP-smeared staggered fermions on the MILC asqtad 2+1 flavor lattices. We use four different lattice spacings ($a \approx$ 0.12, 0.09, 0.06 and 0.045 fm) to control the continuum…

We present a high-statistics lattice calculation of the kinetic energy $-\lambda_1/2 m_b$ of the heavy quark inside the $B$-meson and of the chromo-magnetic term $\lambda_2$, related to the $B^*$--$B$ mass splitting, performed in the HQET.…

High Energy Physics - Lattice · Physics 2009-10-09 V. Gimenez , G. Martinelli , C. T. Sachrajda

We test the convergence property of the chiral perturbation theory (ChPT) using a lattice QCD calculation of pion mass and decay constant with two dynamical quark flavors. The lattice calculation is performed using the overlap fermion…

High Energy Physics - Lattice · Physics 2019-08-14 J. Noaki , S. Aoki , T. W. Chiu , H. Fukaya , S. Hashimoto , T. H. Hsieh , T. Kaneko , H. Matsufuru , T. Onogi , E. Shintani , N. Yamada

We report calculations of the parameter B_K appearing in the Delta S=2 neutral kaon mixing matrix element, whose uncertainty limits the power of unitarity triangle constraints for testing the standard model or looking for new physics. We…

High Energy Physics - Lattice · Physics 2010-02-03 UKQCD collaboration , J. M. Flynn , F. Mescia , A. S. B. Tariq

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

I review recent progresses in heavy quarks physics on the lattice. I focus on decay constants and form factors relevant for the extraction of CKM matrix elements from experimental data. B-\bar{B} mixing is also discussed. In the last part…

High Energy Physics - Lattice · Physics 2009-01-06 Michele Della Morte

We calculate the $B \to\pi\ell\nu$ and $B_s \to K \ell\nu$ form factors in dynamical lattice QCD. We use the (2+1)-flavor RBC-UKQCD gauge-field ensembles generated with the domain-wall fermion and Iwasaki gauge actions. For the $b$ quarks…

High Energy Physics - Lattice · Physics 2015-04-28 J. M. Flynn , T. Izubuchi , T. Kawanai , C. Lehner , A. Soni , R. S. Van de Water , O. Witzel

We calculate semileptonic form factors for the decays $B_c \to \eta_c \, l \nu$ and $B_c \to J/\psi \, l \nu$ over the entire $q^2$ range, using a highly improved lattice quark action for charm at several lattice spacings down to $a=0.045$…

High Energy Physics - Lattice · Physics 2016-11-08 Brian Colquhoun , Christine Davies , Jonna Koponen , Andrew Lytle , Craig McNeile

The static $B^{*}B\pi$ coupling, $\hat{g}_\chi$, a low energy constant in the leading order heavy meson chiral Lagrangian, is determined using $N_\mathrm{f} = 2$ lattice QCD. We use CLS ensembles with lattice spacings and pion masses down…

High Energy Physics - Lattice · Physics 2015-06-19 Fabio Bernardoni , John Bulava , Michael Donnellan , Rainer Sommer

We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the "2+1" flavor gauge…

In this paper, we calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to the exclusive processes $B_c^+\to \chi_{cJ}(h_c)\pi^+$ in the framework of the nonrelativistic QCD (NRQCD) factorization formalism. The…

High Energy Physics - Phenomenology · Physics 2021-07-28 Zi-Qiang Chen , Cong-Feng Qiao

We point out that applying the photon energy cut significantly modifies the moments of energy spectrum in B->X_s+gamma decays, with a certain class of effects not accounted for in the mostly used OPE expressions. This leads to a systematic…

High Energy Physics - Phenomenology · Physics 2010-04-05 I. I. Bigi , N. Uraltsev

The nonlocal order parameters of the QCD chiral symmetry breaking, namely the nonanomalous three-point Green functions of the quark bilinears belonging to the odd intrinsic parity sector, are studied within the framework of the Resonance…

High Energy Physics - Phenomenology · Physics 2023-04-05 Tomas Kadavy , Karol Kampf , Jiri Novotny

We present the first unquenched lattice-QCD calculation of the form factors for the decay $B\rightarrow D^\ast\ell\nu$ at nonzero recoil. Our analysis includes 15 MILC ensembles with $N_f=2+1$ flavors of asqtad sea quarks, with a strange…

The computation of the form factors for the $B_s \to K \ell \nu$ decay is presented. The b quark is treated by means of Heavy Quark Effective Theory, currently in the static approximation. In these proceedings we discuss the extraction of…

High Energy Physics - Lattice · Physics 2017-01-13 F. Bahr , D. Banerjee , M. Koren , H. Simma , R. Sommer

The inclusive decay rate b to ccs is enhanced considerably due to perturbative QCD corrections. We recalculate the dominant part of the NLO-QCD corrections, because they cannot be reconstructed from the literature and we give the full…

High Energy Physics - Phenomenology · Physics 2015-06-16 Fabian Krinner , Alexander Lenz , Thomas Rauh

Using the background field method, we, in the large $N_f$ approximation, calculate the beta function of scalar quantum electrodynamics at the first nontrivial order in $1/N_f$ by two different ways. In the first way, we get the result by…

High Energy Physics - Theory · Physics 2019-03-12 Zhi-Yuan Zheng , Gai-Ge Deng

The semileptonic process, B --> \pi l \nu, is studied via full QCD Lattice simulations. We use unquenched gauge configurations generated by the MILC collaboration. These include the effect of vacuum polarization from three quark flavors:…

High Energy Physics - Lattice · Physics 2014-11-17 Emel Gulez , Alan Gray , Matthew Wingate , Christine T. H. Davies , G. Peter Lepage , Junko Shigemitsu

The effects of initial $b$ quark bound state for the semi-inclusive decays $B\to K(K^*) X$ are studied using light cone expansion and heavy quark effective theory methods. We find that the initial bound state effects on the branching ratios…

High Energy Physics - Phenomenology · Physics 2014-11-17 Xiao-Gang He , Changhao Jin , J. P. Ma

We calculate the leading-order matrix element for exclusive decays of $b \to s\gamma$ in the quenched approximation of lattice QCD on a $24^3\times48$ lattice at $\beta=6.2$, using an O(a)-improved fermion action. The matrix element is used…

High Energy Physics - Lattice · Physics 2009-10-22 K. C. Bowler