A search for the decays Bs-->mumu and Bd-->mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The ...observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs-->mumu) < 5.6 x 10^{-8} and BR(Bd-->mumu) <1.5 x 10^{-8} at 95% confidence level.
We give here a short review of the LHCb Silicon Tracker, the main points of the module production and quality control, followed by the commissioning of the detector. Problems that were found during ...production or commissioning are described and the first performance assessment of the installed detector with “beam data” is given.
The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is ...determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.
The LHCb Silicon Tracker will cover a sensitive surface of about
12
m
2
with silicon micro-strip detectors. The production of detector modules is currently coming close to its conclusion. In this ...paper, the design of the detector modules, the main module production steps, and the module quality assurance programme are described. Selected results from the quality assurance are shown and first lessons are drawn from the experience gained during module production.
The LHCb computing data challenge DC06 Nandakumar, R; Jimenez, S G; Adinolfi, M ...
Journal of physics. Conference series,
07/2008, Letnik:
119, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The worldwide computing grid is essential to the LHC experiments in analysing the data collected by the detectors. Within LHCb, the computing model aims to simulate data at Tier-2 grid sites as well ...as non-grid resources. The reconstruction, stripping and analysis of the produced LHCb data will pimarily place at the Tier-1 centres. The computing data challenge DC06 started in May 2006 with the primary aims being to exercise the LHCb computing mod and to produce events which will be used for analyses in the forthcoming LHCb physics book. This paper gives an overview of the LHCb computing model and addresses the challenges and experiences during DC06. The management of the production of Monte Carlo data on the LCG was done using the DIRAC worklad management system which in turn uses the WLCG infrastructure and middleware. We shall report on the amount of data simulated during DC06, including the performance of the sites used. The paper will also summarise the experience gained during DC06, in particular he distribution of data to the Ter-1 sits and the access to this data.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The angular distribution and differential branching fraction of the decay B super(0) arrow right K super(0) mu super(+) mu ...super(-) are studied using a data sample, collected by the LHCb experiment in pp collisions at ... TeV, corresponding to an integrated luminosity of 1.0 fb super(-1). Several angular observables are measured in bins of the dimuon invariant mass squared, q super(2). A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be ..., where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The determination of the differential branching fraction and the first angular analysis of the decay ... arrow right mu ...super(+) mu super(-) are presented using data, corresponding to an integrated luminosity of 1.0 fb super(-1), collected by the LHCb experiment at ...TeV. The differential branching fraction is determined in bins of q super(2), the invariant dimuon mass squared. Integration over the full q super(2) range yields a total branching fraction of ... 10 super(-7), where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables F sub(L), S sub(3), A sub(6), and A sub(9). The observables are consistent with Standard Model expectations. Figure not available: see fulltext.
PDF
