LHCb

Abstract:

A search for the decays of the B+c meson to ppπ+ is performed for the first time using a data sample corresponding to an integrated luminosity of 3.0 fb-1 collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. No signal is found and an upper limit, at 95% confidence level, is set, fc/fu × B(B+c → ppπ+) < 3.6×10^-8 in the kinematic region m(pp) < 2.85 GeV/c^2, pT(B) < 20 GeV/c and 2.0 < y(B) < 4.5, where B is the branching fraction and fc(fu) is the fragmentation fraction of the b quark into a Bc+ (B+) meson.

Abstract:

Background

Several regions of the genome have shown to be associated with COPD in genome-wide association studies of common variants.

Objective

To determine rare and potentially functional single nucleotide polymorphisms (SNPs) associated with the risk of COPD and severity of airflow limitation.

Methods

3226 current or former smokers of European ancestry with lung function measures indicative of Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2 COPD or worse were genotyped using an exome array. An analysis of risk of COPD was carried out using ever smoking controls (n=4784). Associations with %predicted FEV1 were tested in cases. We followed-up signals of interest (p<10(-5)) in independent samples from a subset of the UK Biobank population and also undertook a more powerful discovery study by meta-analysing the exome array data and UK Biobank data for variants represented on both arrays.

Results

Among the associated variants were two in regions previously unreported for COPD; a low frequency non-synonymous SNP in MOCS3 (rs7269297, pdiscovery=3.08×10(-6), preplication=0.019) and a rare SNP in IFIT3, which emerged in the meta-analysis (rs140549288, pmeta=8.56×10(-6)). In the meta-analysis of % predicted FEV1 in cases, the strongest association was shown for a splice variant in a previously unreported region, SERPINA12 (rs140198372, pmeta=5.72×10(-6)). We also confirmed previously reported associations with COPD risk at MMP12, HHIP, GPR126 and CHRNA5. No associations in novel regions reached a stringent exome-wide significance threshold (p<3.7×10(-7)).

Conclusions

This study identified several associations with the risk of COPD and severity of airflow limitation, including novel regions MOCS3, IFIT3 and SERPINA12, which warrant further study.

Abstract:

The decays Λb0→ ψ(2S)pK− and Λb0→ J/ψπ+π−pK−are observed in a data sample corresponding to an integrated luminosity of 3 fb^−1, collected in proton-proton collisions at 7 and 8 TeV centre-of-mass energies by the LHCb detector. The ψ(2S) mesons are reconstructed through the decay modes ψ(2S) → μ+μ−and ψ(2S) → J/ψπ+π−. The branching fractions relative to that of Λb0→ J/ψpK−are measured to be ℬ(Λb0→ψ(2S)pK−)/ℬ(Λb0→J/ψpK−) = (20.70±0.76±0.46±0.37) × 10^−2, ℬ(Λb0→ψ(2S)pK−)/ℬ(Λb0→J/ψpK−) = (20.86±0.96±1.34)×10^−2 where the first uncertainties are statistical, the second are systematic and the third is related to the knowledge of J/ψ and ψ(2S) branching fractions. The mass of the Λb0baryon is measured to be M(Λb0) = 5619.65 ± 0.17 ± 0.17MeV/c2, where the uncertainties are statistical and systematic.

Abstract:

© 2016 CERN, for the LHCb Collaboration. Published by the American Physical Society under the terms of the http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb-1 collected by LHCb at s=7 and 8 TeV, is used to reconstruct 63±9 Ωb-→Ωc0π-, Ωc0→pK-K-π+ decays. Using the Ξb-→Ξc0π-, Ξc0→pK-K-π+ decay mode for calibration, the lifetime ratio and the absolute lifetime of the Ωb- baryon are measured to be τΩb-/τΞb-=1.11±0.16±0.03, τΩb-=1.78±0.26±0.05±0.06 ps, where the uncertainties are statistical, systematic and from the calibration mode (for τΩb- only). A measurement is also made of the mass difference, mΩb - mΞb-, and the corresponding Ωb- mass, which yields mΩb - mΞb-=247.4±3.2±0.5 MeV/c2, mΩb-=6045.1±3.2±0.5±0.6 MeV/c2. These results are consistent with previous measurements.

Abstract:

A search is performed for the charmless three-body decays of the Λb0 and Ξb0 baryons to the final states Λh+h′−, where h(′) = π or K. The analysis is based on a data sample, corresponding to an integrated luminosity of 3 fb−1 of pp collisions, collected by the LHCb experiment. The Λb0 → ΛK+π− and Λb0 → ΛK+K− decays are observed for the first time and their branching fractions and CP asymmetry parameters are measured. Evidence is seen for the Λb0 → Λπ+π− decay and limits are set on the branching fractions of Ξb0 baryon decays to the Λh+h′− final states.