The branching fraction ratio R(D^{*})≡B(B[over ¯]^{0}→D^{*+}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]^{0}→D^{*+}μ^{-}ν[over ¯]_{μ}) is measured using a sample of proton-proton collision data corresponding to 3.0  fb^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate B[over ¯]^{0} decays gives R(D^{*})=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model.

A detailed analysis is presented of the diffractive deep-inelastic scattering process ep → eXY , where Y is a proton or a low mass proton excitation carrying a fraction 1−x I P > 0.95 of the incident proton longitudinal momentum and the squared four-momentum transfer at the proton vertex satisfies |t| < 1 GeV 2 . Using data taken by the H1 experiment, the cross section is measured for photon virtualities in the range 3.5 ≤ Q 2 ≤ 1600 GeV 2 , triple differentially in x I P , Q 2 and β = x/x I P , where x is the Bjorken scaling variable. At low x I P , the data are consistent with a factorisable x I P dependence, which can be described by the exchange of an effective pomeron trajectory with intercept α IP (0) = 1.118 ± 0.008 (exp.) +0.029 −0.010 (model). Diffractive parton distribution functions and their uncertainties are determined from a next-to-leading order DGLAP QCD analysis of the Q 2 and β dependences of the cross section. The resulting gluon distribution carries an integrated fraction of around 70% of the exchanged momentum in the Q 2 range studied. Total and differential cross sections are also measured for the diffractive charged current process e + p →ν e XY and are found to be well described by predictions based on the diffractive parton distributions. The ratio of the diffractive to the inclusive neutral current ep cross sections is studied. Over most of the kinematic range, this ratio shows no significant dependence on Q 2 at fixed x I P and x or on x at fixed Q 2 and β.

We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)(0)μ(+)μ(-). The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV. Four observables are measured in six bins of the dimuon invariant mass squared q² in the range 0.1

A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum p jet 1(2) t > 11(8) GeV in the central range of pseudo-rapidity −0.9 < η jet 1(2) < 1.3. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable x obs γ . Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement.

An angular analysis and a measurement of the differential branching fraction of the decay B 0 s → φµ + µ − are presented, using data corresponding to an integrated luminosity of 3.0 fb −1 of pp collisions recorded by the LHCb experiment at √ s = 7 and 8 TeV. Measurements are reported as a function of q 2 , the square of the dimuon invariant mass and results of the angular analysis are found to be consistent with the Standard Model. In the range 1 < q 2 < 6 GeV 2 /c 4 , where precise theoretical calculations are available, the differential branching fraction is found to be more than 3 σ below the Standard Model predictions. The LHCb collaboration 30 IntroductionThe decay B 0 s → φµ + µ − is mediated by a b → s flavour changing neutral current (FCNC) transition. In the Standard Model (SM) it is forbidden at tree-level and proceeds via loop diagrams as shown in figure 1. In extensions of the SM, new heavy particles can appear in competing diagrams and affect both the branching fraction of the decay and the angular distributions of the final-state particles.This decay channel was first observed and studied by the CDF collaboration [1, 2] and subsequently studied by the LHCb collaboration using data collected during 2011, corresponding to an integrated luminosity of 1.0 fb −1 [3]. While the angular distributions were found to be in good agreement with SM expectations, the measured branching fraction differs from the recently updated SM prediction by 3.1 σ [4,5]. A similar trend is also seen for the branching fractions of other b → sµ + µ − processes, which tend to be lower than SM predictions [6-8].-1 - JHEP09(2015)179This paper presents an updated analysis of the decay B 0 s → φ(→ K + K − )µ + µ − using data accumulated by LHCb in pp collisions, corresponding to an integrated luminosity of 1.0 fb −1 collected during 2011 at 7 TeV and 2.0 fb −1 collected during 2012 at 8 TeV centreof-mass energy. The differential branching fraction dB(B 0 s → φµ + µ − )/dq 2 is determined as a function of q 2 , the square of the dimuon invariant mass. In addition, a three-dimensional angular analysis in cos θ l , cos θ K and Φ is performed in bins of q 2 . Here, the angle θ K (θ l ) denotes the angle of the K − (µ − ) with respect to the direction of flight of the B 0 s meson in the K + K − (µ + µ − ) centre-of-mass frame, and Φ denotes the angle between the µ + µ − and the K + K − decay planes in the B 0 s meson centre-of-mass frame. Compared to the previously published fit of the one-dimensional projections of the decay angles [3], the full three-dimensional angular fit gives improved sensitivity and allows access to more angular observables.The decay B 0 s → φµ + µ − is closely related to the decay B 0 → K * 0 µ + µ − , which has been studied extensively by LHCb [6,9, 10]. Although B 0 s meson production is suppressed with respect to the B 0 meson by the fragmentation fraction ratio f s /f d ∼ 1/4, the narrow φ resonance allows a clean selection with low background levels. Furthermore, the contribution from the S wave, w...