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A bstract We investigate the physics reach and potential for the study of B -meson decays to invisible final states at the Future Circular Collider running electron-positron collisions at the Z pole (FCC-ee). Signal and background candidates are simulated for a proposed multipurpose detector, including inclusive contributions from Z decays to leptons or quarks. Signal candidates are selected by a mixture of rectangular cuts and a multiclass boosted decision tree classifier. We determine that branching fractions above 7 . 6 × 10 − 9 (9 . 7 × 10 − 9 ) would be excluded at 90% (95%) confidence level, and branching fractions above 3 . 0 × 10 − 8 would be within discovery reach at FCC-ee if 6 × 10 12 Z bosons are produced.

A measurement of the phase difference between the short- and long-distance contributions to the [Formula: see text] decay is performed by analysing the dimuon mass distribution. The analysis is based on collision data corresponding to an integrated luminosity of 3[Formula: see text] collected by the LHCb experiment in 2011 and 2012. The long-distance contribution to the [Formula: see text] decay is modelled as a sum of relativistic Breit-Wigner amplitudes representing different vector meson resonances decaying to muon pairs, each with their own magnitude and phase. The measured phases of the [Formula: see text] and [Formula: see text] resonances are such that the interference with the short-distance component in dimuon mass regions far from their pole masses is small. In addition, constraints are placed on the Wilson coefficients, [Formula: see text] and [Formula: see text], and the branching fraction of the short-distance component is measured.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Measurements are presented of electroweak boson production using data from pp collisions at a centre-of-mass energy of ... TeV. The analysis is based on an integrated luminosity of 2.0 fb super(-1) recorded with the LHCb detector. The bosons are identified in the W arrow right mu nu and Z arrow right mu super(+) mu super(-) decay channels. The cross-sections are measured for muons in the pseudorapidity range 2.0 < eta < 4.5, with transverse momenta p sub(T) > 20 GeV/c and, in the case of the Z boson, a dimuon mass within ... GeV/c super(2). The results are ... ... ... ... ... ... ... ... where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. The evolution of the W and Z boson cross-sections with centre-of-mass energy is studied using previously reported measurements with 1.0 fb super(-1) of data at 7 TeV. Differential distributions are also presented. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. [Figure not available: see fulltext.]

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The associated production of a Z boson or an off-shell photon gamma super( )*with a bottom quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy of 7 TeV. The Z bosons are reconstructed in the Z/ gamma super( )* arrow right mu super( )+ mu super( )-final state from muons with a transverse momentum larger than 20 GeV, while two transverse momentum thresholds are considered for jets (10 GeV and 20 GeV). Both muons and jets are reconstructed in the pseudorapidity range 2.0 < eta < 4.5. The results are based on data corresponding to 1.0 fb super(-1) recorded in 2011 with the LHCb detector. The measurement of the Z+b-jet cross-section is normalized to the Z+jet cross-section. The measured cross-sections are ... ... for p sub(T)(jet) > 10 GeV, and ... ... for p sub(T)(jet) > 20 GeV. [Figure not available: see fulltext.]

Abstract Two new algorithms for use in the analysis of$$pp$$p p collision are developed to identify the flavour of$${\\mathrm {B}} ^0$$B 0 mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using$${{\\mathrm {B}} ^0} \\!\\rightarrow D^{-}\\pi ^{+}$$B 0 → D - π + decays from$$pp$$p p collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a$${\\mathrm {B}} ^0$$B 0 meson is the first of its kind.

Two new algorithms for use in the analysis of [Formula: see text] collision are developed to identify the flavour of [Formula: see text] mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using [Formula: see text] decays from [Formula: see text] collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a [Formula: see text] meson is the first of its kind.

The decays [Formula: see text] and [Formula: see text] are observed for the first time using a data sample corresponding to an integrated luminosity of 3.0 fb[Formula: see text], collected by the LHCb experiment in proton-proton collisions at the centre-of-mass energies of 7 and 8[Formula: see text]. The branching fractions relative to that of [Formula: see text] are measured to be [Formula: see text]where the first uncertainties are statistical and the second are systematic.

The oscillation frequency, [Formula: see text], of [Formula: see text] mesons is measured using semileptonic decays with a [Formula: see text] or [Formula: see text] meson in the final state. The data sample corresponds to 3.0[Formula: see text] of collisions, collected by the LHCb experiment at centre-of-mass energies [Formula: see text] = 7 and 8[Formula: see text]. A combination of the two decay modes gives [Formula: see text], where the first uncertainty is statistical and the second is systematic. This is the most precise single measurement of this parameter. It is consistent with the current world average and has similar precision.

The lifetime of the [Formula: see text] meson is measured using semileptonic decays having a [Formula: see text] meson and a muon in the final state. The data, corresponding to an integrated luminosity of [Formula: see text], are collected by the LHCb detector in [Formula: see text] collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is [Formula: see text]where the first uncertainty is statistical and the second is systematic.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A study of ... meson production at LHCb is performed on proton-proton collision data, corresponding to 3.0...of integrated luminosity collected at centre-of-mass energies ... = 7 and 8 ... The fraction of ... mesons originating from ... decays is measured as a function of the ... transverse momentum in the rapidity range ... The radiative transition of the ... meson to ... is observed for the first time. The ... mass is determined to be ... ...where the first uncertainty is statistical and the second is systematic.