Abstract: Using a data set corresponding to an integrated luminosity of 3fb(-1), collected by the LHCb experiment in ppcollisions at centre-of-mass energies of 7 and 8TeV, the effective lifetime in the B-s(0) -> J/Psi eta decay mode, teff, is measured to be tau(eff) = 1.479 +/- 0.034 (stat)+/- 0.011 (syst) ps. Assuming CP conservation, tau(eff) corresponds to the lifetime of the light B-s(0) mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.

Abstract: The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg(2), and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg(2) and probes a volume of 3 h(-3) Gpc(3), making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of similar to 15%, with a bin size of delta(l) = 10 on scales of the baryon acoustic oscillations (BAOs; at l similar to 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat Lambda CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H-0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find Omega(Lambda) = 0.73 +/- 0.019 and H-0 to be 70.5 +/- 1.6 s(-1) Mpc(-1) km. For an open Lambda CDM model, when combined with WMAP7 + HST, we find Omega(K) = 0.0035 +/- 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+ SN, we find w = -1.071 +/- 0.078, and H-0 to be 71.3 +/- 1.7 s(-1) Mpc(-1) km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power spectra give consistent constraints on cosmological models when compared with pre-systematic correction power spectra in the angular scales of interest. The SDSS-III Data Release 8 (SDSS-III DR8) Angular Clustering Data allow a wide range of investigations into the cosmological model, cosmic expansion (via BAO), Gaussianity of initial conditions, and neutrino masses. Here, we refer to our companion papers for further investigations using the clustering data. Our calculation of the survey selection function, systematics maps, and likelihood function for the COSMOMC package will be released at http://portal.nersc.gov/project/boss/galaxy/photoz/.

Abstract: This paper describes a measurement of the inclusive top quark pair production cross-section (sigma(t (t) over bar)) with a data sample of 3.2 fb(-1) of proton-proton collisions at a centre-of-mass energy of root s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron-muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously sigma(t (t) over bar) and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: s(t (t) over bar)= 818 +/- 8 (stat) +/- 27 (syst) +/- 19 (lumi) +/- 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented.

Abstract: The top quark mass is measured in the t (t) over bar -> dilepton channel (lepton= e, mu) using ATLAS data recorded in the year 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of root s = 8 TeV and correspond to an integrated luminosity of about 20.2 fb(-1). Exploiting the template method, and using the distribution of invariant masses of lepton-b-jetpairs, the top quark mass is measured to be m(top) = 172.99 +/- 0.41(stat)+/- 0.74(syst) GeV, with a total uncertainty of 0.84 GeV. Finally, acombination with previous ATLAS m(top) measurements from root s = 7 TeV data in the t (t) over bar -> dilepton and t (t) over bar -> lepton + jets channels results in m(top) = 172.84 +/- 0.34(stat)+/- 0.61(syst) GeV, with a total uncertainty of 0.70 GeV.

Abstract: We propose a simple Delta (27) circle times Z(4) model where neutrinos are predicted to be Dirac fermions. The smallness of their masses follows from a type-I seesaw mechanism and the leptonic CP violating phase correlates with the pattern of Delta(27) flavor symmetry breaking. The scheme naturally harbors a WIMP dark matter candidate associated to the Dirac nature of neutrinos, in that the same Z(4) lepton number symmetry also ensures dark matter stability.