Conveners
WG2
- Michele Della Morte (Unknown)
WG2
- Phillip Urquijo (University of Melbourne (AU))
WG2
- Michele Della Morte (Unknown)
WG2
- Alexander Khodjamirian (University of Siegen)
WG2
- Michele Della Morte (Unknown)
-
Martin Heck (Karlsruhe Institute of Technology)08/09/2014, 14:30Leptonic decays of B mesons are well understood in the Standard Model (SM) and highly suppressed due to helicity conservation. The leptonic branching fraction measurements can provide stringent constraints on New Physics, where particles or forces outside of the SM can suppress or enhance the decay rate. Experimentally, due to the small branching fractions, it is a challenge to measure the...Go to contribution page
-
Heechang Na08/09/2014, 14:50In this talk, I will review lattice calculations on B meson decay constants, f_B, f_Bs, and f_Bs/f_B. I will focus on recent calculations from N_f = 2+1 and 2+1+1 lattice gauge configurations. Moreover, I will compare between calculations utilizing different heavy quark discritization methods such as Fermilab interpretation, HISQ, and NRQCD action.Go to contribution page
-
Gregorio HERDOIZA08/09/2014, 15:08We discuss a lattice QCD computation of the B-meson decay constants by the ETM collaboration where suitable ratios allow to reach the bottom quark sector by combining simulations around the charm-quark mass with an exactly known static limit. The extrapolations to the continuum limit and to the physical point as well as other sources of systematic uncertainties are analysed. A comparison of...Go to contribution page
-
Alexander Khodjamirian (University of Siegen)08/09/2014, 15:26I will present the current status of the B\to \pi form factors calculated from QCD LCSR at large hadronic recoil. New updated uncertainty estimates and extrapolations of the form factors are obtained, together with model-independent unitarity bounds. Related results for the other heavy-to-light hadronic matrix elements will be overviewed.Go to contribution page
-
Silvano SIMULA08/09/2014, 15:50In this talk I will present the lattice averages for the decay constants of the D- and the B-meson performed by the Flavor Lattice Averaging Group (FLAG) and compare them with the corresponding updated predictions from Borel QCD Sum Rules for heavy-light currents. An excellent agreement is obtained in the charm sector, while some tension can be observed in the bottom sector. Furthermore,...Go to contribution page
-
Robin Glattauer (Vienna)08/09/2014, 16:45The most precise measurements of Vcb today come from semileptonic B decays at the B-factories BaBar and Belle. We present an overview of their measurements with a focus on the most recent results. Different approaches are used to determine Vcb: inclusive and exclusive measurements; tagged and untagged analyses or global fits. We also give a summary on how the most recent measurements affect...Go to contribution page
-
Paolo Gambino (Universita e INFN (IT))08/09/2014, 17:05The extraction of Vcb from fits to inclusive semileptonic B decays is reviewed, with emphasis on recent developments and in particular on the effect of higher order corrections and on heavy mass constraints.Go to contribution page
-
Francesco SANFILIPPO08/09/2014, 17:30We present the results for the normalization of the relevant form factor mediating the semileptonic B-->Dlnu and Bs-->Ds lnu decays in the Standard Model, as obtained by using the maximally twisted mass QCD on the lattice with Nf=2 dynamical light quarks, and with the fully propagating heavy quark. Furthermore, the form factors needed for description of these decays in a generic scenarios of...Go to contribution page
-
Daping Du (University of Illinois, Urbana-Champaign)08/09/2014, 17:50I will discuss the recent results for the B->D*lv and B->Dlv semileptonic form factors and the determination of |V_cb| from the Fermilab/MILC collaborations. These lattice calculations use an improved staggered action for the light quarks and the Fermilab action for the charm and bottom quarks; the calculation uses the MILC (asqtad) ensembles with three flavors of sea quarks and five lattice...Go to contribution page
-
Dr Florian Urs Bernlochner (Universitaet Bonn (DE))08/09/2014, 18:10The experimental knowledge of semileptonic B decays to a D or D* meson with one or more pions is limited. These limitations are relevant to two experimental puzzles: the tension between the values of Vcb determined from inclusive and exclusive semileptonic decays, and the gap between the sum of the exclusive semileptonic B decays to charm and the inclusive b -> c l nu rate. The full...Go to contribution page
-
Mr Bahman Dehnadi (University of Vienna)08/09/2014, 18:29We briefly review recent charm and bottom mass determinations based on perturbative QCD. We give new results on MSbar charm mass using as input lattice moments of the pseudoscalar current correlator. We also give an update on the MSbar bottom mass based on e+e- data, which quantifies the uncertainties from energies where no measurements exist and uses latest theory input. Both analyses are...Go to contribution page
-
Basem Khanji (Universita & INFN, Milano-Bicocca (IT))10/09/2014, 09:00LHCb has recorded large samples of semileptonic decays of c- and b-flavoured hadrons. We review the latest results in semileptonic decays of B, Bs and Λb decays. Recent results on CP violation and determination of CKM matrix elements are shown.Go to contribution page
-
Alexander Ermakov (Bonn)10/09/2014, 09:25In this talk I give an experimental review of the current status of |V_ub| determinations. Precision measurements of charmless semileptonic B-decays allow for a determination of the magnitude of the CKM matrix element V_ub, for a test of the consistency of the CKM mechanism and potentially of NP scenarios. In this talk the various experimental methods to determine |V_ub| based on...Go to contribution page
-
Chris Bouchard (University of Illinois)10/09/2014, 09:45Recently published and preliminary Fermilab/MILC and HPQCD lattice QCD calculations of form factors for B -> pi l nu and Bs -> K l nu will be presented. In combination with existing experiment, these results generate a significant reduction in the error of Vub. I will also discuss plans to improve the lattice calculations, including the use of a fully relativistic b quark to eliminate...Go to contribution page
-
Mr Felix Bahr (DESY Zeuthen)10/09/2014, 10:05We present the current status of the ongoing work of the ALPHA collaboration on the computation of the form factor $f_+ (q^2)$ for the semi-leptonic decay $\textnormal B_\textnormal s \to \textnormal K \ell \nu$. We simulate on lattices generated as part of the Coordinated Lattice Simulations (CLS) effort which have $N_\textnormal f=2$ non-perturbatively $O(a)$ improved Wilson fermions that...Go to contribution page
-
Dr Benoit Blossier (CNRS/Laboratoire de Physique Théorique d'Orsay)10/09/2014, 10:25Understanding the composition of final states in B --> Xc l nu could help to get a feedback on the persisting disagreement between exclusive and inclusive determinations of Vcb. In particular the series of orbital excitations D** and radial excitations (D', D*') has received a lot of attention; a misinterpretation as a scalar state of the (D' --> D pi) spectrum tail could have induced an...Go to contribution page
-
Vera Luth (SLAC)10/09/2014, 11:15Measurement of the D -> pi- e+ nu partial branching fraction, form factor and implications for Vub. Precision measurements of the D -> pi e+ nu form factor could shed new light on the persistent difference between inclusive and exclusive measurements of Vub. We report the measurement of the partial branching fraction of D -> pi e+ nu in bins of the four-momentum transfer squared of the...Go to contribution page
-
Andreas Crivellin (University Bern)10/09/2014, 11:35In this talk I review the flavour phenomenology of two-Higgs-doublet models with generic Yukawa structure. After discussing the constraints from FCNC I show that even taking into account these bound, one can still get sizable effects in B->(D^(*))tau nu. In order to explain the observed deviations in tauonic B decays from the SM large flavour-changing elements connecting top and charm are...Go to contribution page
-
Alejandro Celis (IFIC CSIC-Universitat de Valencia)10/09/2014, 11:55I will discuss the status of B to D(*) Tau Nu decays in the context of the aligned two-Higgs-doublet model. The sensitivity of these decays to charged scalar contributions will be considered, taking into account constraints from leptonic meson decays and direct searches for a charged Higgs at colliders. The role of differential distributions to discriminate a charged scalar from other types...Go to contribution page
-
Vikas Bansal (PNNL)10/09/2014, 12:15I will review the current status of measurements involving semi-tauonic B meson decay at the B-factories. I will briefly touch upon the experimental methods and highlight the importance of backgrounds especially from poorly understood D** in this study. Perhaps this can also shed some light on the discrepancy in BaBar’s measurement of ratio of semi-tauonic and semi-leptonic (e / \mu)...Go to contribution page
-
Fulvia De Fazio (INFN - Sezione di Bari)10/09/2014, 12:35The BaBar measurements of the ratios ${\cal R}(D^{(*)})=\frac{{\cal B}(B \to D^{(*)} \tau {\bar \nu}_\tau)}{{\cal B}(B \to D^{(*)} \mu {\bar \nu}_\mu)}$ deviate from the standard model expectation, while new results on the purely leptonic $B \to \tau {\bar \nu}_\tau$ mode show a better consistency with the standard model, within the uncertainties. In a new physics scenario, one possibility to...Go to contribution page
-
Dr Matthew Wingate (University of Cambridge)11/09/2014, 09:20We present a brief review of our lattice calculation of $\Lambda_b \to p$ form factors in the static $b$ quark limit. A new calculation using relativistic $b$ quarks is underway and its status will be discussed.Go to contribution page
-
Dr Nazario Tantalo (Rome University "Tor Vergata")11/09/2014, 09:40In this talk I shall discuss, from a methodological point of view, some of the theoretical and numerical problems that arise in lattice calculations of heavy flavoured hadronic observables. I shall also emphasize the importance of non-perturbative lattice techniques for the calculation of heavy quark masses and give an outlook on the possibility of performing lattice calculations of QED...Go to contribution page
-
Dr Andrey Tayduganov (Osaka University)11/09/2014, 10:05The observed discrepancy between the experimental results and the Standard Model prediction for the ratios of the branching fractions of the decays B-> D(*) tau nu and B-> D(*) mu nu came as a surprise and lead to a discussion of testing New Physics through these modes. We discuss the possibilities for observing the New Physics effects by examining the q^2 and the angular distributions of...Go to contribution page
-
Dr Guglielmo De Nardo (INFN Napoli)11/09/2014, 10:25