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A bstract The isospin asymmetries of B → Kμ + μ − and B → K * μ + μ − decays and the partial branching fractions of the B 0 → K 0 μ + μ − , B + → K + μ + μ − and B + → K *+ μ + μ − decays are measured as functions of the dimuon mass squared, q 2 . The data used correspond to an integrated luminosity of 3 fb −1 from proton-proton collisions collected with the LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV in 2011 and 2012, respectively. The isospin asymmetries are both consistent with the Standard Model expectations. The three measured branching fractions favour lower values than their respective theoretical predictions, however they are all individually consistent with the Standard Model.

During 2011 the LHCb experiment at CERN collected 1.0 fb −1 of pp collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract The production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV, using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36 fb^sup -1^. The B ^sup +^, B ^sup 0^ and ... mesons are reconstructed in the exclusive decays B ^sup +^ [arrow right] J/[psi]K ^sup +^, B ^sup 0^ [arrow right] J/[psi]K ^sup *0^ and ..., with J/[psi] [arrow right] [mu] ^sup +^ [mu] ^sup -^, K ^sup *0^ [arrow right] K ^sup +^[pi]^sup -^ and [arrow right] K ^sup +^ K ^sup -^. The differential cross-sections are measured as functions of B meson transverse momentum p ^sub T^ and rapidity y, in the range 0 < p ^sub T^ < 40 GeV/c and 2.0 < y < 4.5. The integrated cross-sections in the same p ^sub T^ and y ranges, including charge-conjugate states, are measured to be ...where the third uncertainty arises from the pre-existing branching fraction measurements. [Figure not available: see fulltext.]

A bstract Using three- and four-body decays of D mesons produced in semileptonic b -hadron decays, precision measurements of D meson mass differences are made together with a measurement of the D 0 mass. The measurements are based on a dataset corresponding to an integrated luminosity of 1 . 0 fb −1 collected in pp collisions at 7 TeV. Using the decay D 0 → K + K − K − π + , the D 0 mass is measured to be The mass differences are measured using the D 0 → K + K − π + π − and modes.

The calibration and performance of the opposite-side flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + → J / ψK + , B 0 → J / ψK ∗0 and B 0 → D ∗− μ + ν μ decay modes with 0.37 fb −1 of data collected in pp collisions at during the 2011 physics run. The opposite-side tagging power is determined in the B + → J / ψK + channel to be (2.10±0.08±0.24) %, where the first uncertainty is statistical and the second is systematic.

A search is presented for massive long-lived particles, in the 20–60  Ge V / c 2 mass range with lifetimes between 5 and 100  ps . The dataset used corresponds to 0.62 fb - 1 of proton-proton collision data collected by the LHCb detector at s = 7 Te V . The particles are assumed to be pair-produced by the decay of a Higgs-like boson with mass between 80 and 140  Ge V / c 2 . No excess above the background expectation is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime and of the Higgs-like boson mass.

A bstract The angular distribution and differential branching fraction of the decay B + → K + μ + μ − are studied with a dataset corresponding to 1.0fb −1 of integrated luminosity, collected by the LHCb experiment. The angular distribution is measured in bins of dimuon invariant mass squared and found to be consistent with Standard Model expectations. Integrating the differential branching fraction over the full dimuon invariant mass range yields a total branching fraction of ( B + → K + μ + μ − ) = (4 . 36 ± 0 . 15 ± 0 . 18) × 10 −7 . These measurements are the most precise to date of the B + → K + μ + μ − decay.

A bstract A search for associated production of a Z boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0 fb −1 of proton-proton collisions at a centre-of-mass energy of 7TeV, collected by the LHCb experiment. Seven candidate events for associated production of a Z boson with a D 0 meson and four candidate events for a Z boson with a D + meson are observed with a combined significance of 5.1 standard deviations. The production cross-sections in the forward region are measured to be where the first uncertainty is statistical and the second systematic.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract A measurement of the Z([arrow right] [mu] ^sup +^ [mu] ^sup -^) + jet production cross-section in pp collisions at a centre-of-mass energy ... = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0 fb^sup -1^ recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0 < [eta] < 4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction. [Figure not available: see fulltext.]

A search is presented for long-lived particles with a mass between 25 and 50  GeV / c 2 and a lifetime between 1 and 200 ps in a sample of proton–proton collisions at a centre-of-mass energy of s = 7  TeV, corresponding to an integrated luminosity of 0.62  fb - 1 , collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a standard model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime.