20 research outputs found
A precise measurement of the meson oscillation frequency
The oscillation frequency, , of mesons is measured using
semileptonic decays with a or meson in the final state, in a
data sample of collisions collected by the LHCb detector corresponding to
an integrated luminosity of 3.0\mbox{fb}^{-1}. A combination of the two decay
modes gives , where the
first uncertainty is statistical and the second is systematic. This is the most
precise single measurement of this parameter. It is compatible with the current
world average and has similar precision.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-031.htm
Thoracoscopic internal mammary lymph nodes dissection: a staging tool for internal mammary lymph nodes in breast cancer
Imaging of Biliary Disorders: Cholecystitis, Bile Duct Obstruction, Stones, and Stricture
Video-assisted thoracic surgeryâthe past, present status and the future
Video-assisted thoracic surgery (VATS) has developed very rapidly in these two decades, and has replaced conventional open thoracotomy as a standard procedure for some simple thoracic operations as well as an option or a complementary procedure for some other more complex operations. In this paper we will review its development history, the present status and the future perspectives
Effective lifetime measurements in the B-s(0) -> K+K-, B-0 -> K+pi(-) and B-s(0) -> pi K-+(-) decays
Measurements of the effective lifetimes in the B-s(0) -> K+K-, B-0 -> K+pi(-) and B-s(0) -> pi K-+(-) decays are presented using 1.0 fb(-1)of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. The measured effective lifetimes are tau(Bs0 -> K+K-) = 1.407 +/- 0.016 (stat) +/- 0.007 (syst) ps, tau(Bs0 -> K+pi-) = 1.524 +/- 0.011 (stat) +/- 0.004 (syst) ps, tau(Bs0 ->pi+K-) = 1.60 +/- 0.06 (stat) +/- 0.01 (syst) ps. This is the most precise determination to date of the effective lifetime in the B-s(0) -> K+K- decay and provides constraints on contributions from physics beyond the Standard Model to the B-s(0) mixing phase and the width difference Delta Gamma(s). (C) 2014 The Authors. Published by Elsevier B.V
Measurement of the chi(b) (3 P) mass and of the relative rate of chi(b1) (1 P) and chi(b2) (1 P) production
The production of chi(b) mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of root s = 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The chi(b) mesons are identified through their decays to Upsilon(1 S)gamma and Upsilon(2 S)gamma using photons that converted to e(+)e (-) pairs in the detector. The relative prompt production rate of chi(b1)(1 P) and chi(b2)(1 P) mesons is measured as a function of the Upsilon(1 S) transverse momentum in the chi(b) rapidity range 2.0 < y < 4.5. A precise measurement of the chi(b) (3 P) mass is also performed. Assuming a mass splitting between the chi(b1)(3 P) and the chi(b2)(3 P) states of 10.5 MeV/c(2), the measured mass of the chi(b1)(3 P) meson is m (chi(b1)(3 P)) = 10515.7(-3.9)(+2.2)(stat)(-2.1)(+1.5)(syst) MeV/c(2)