685 research outputs found
Indeterminism and non locality
No full textCenter of quantum philosophy of Geneva : John Bell's talk - his theorem and debate. Taking part John Bell, Antoine Suarez, Herwig Schopper, J M Belloc, G Cantale, John Layter, P Veija and P Ypes. Comments : Because of a video recording failure, during the first 2 minutes one only hears the sound of the talk with some pictures as background. Thereafter the full record (video and audio) is played. One can find at transcript of the talk at: www.quantumphil.org.</small
The CMS Muon System
No full textThe muon detection system for the Compact Muon Solenoid ( CMS) detector at LHC is described. Particular attention is given to recent developments in the barrel and endcap chamber R&D programs. The strategy for triggering is discussed briefly
Investigation of the decay of orbitally excited B mesons and first measurement of the branching ratio BR(B*(J) ---> B*pi(X))
No full textFrom about 4 million hadronic Z decays recorded by the OPAL detector on and near to the Z resonance, we select a sample of more than 570000 inclusively reconstructed B mesons. Orbitally-excited mesons B*J are reconstructed using Bpi+- combinations. Independently, B* mesons are reconstructed using the decay B* -> Bgamma. The selected B* candidates are used to obtain samples enriched or depleted in the decay B*J -> B*pi+-(X), where (X) refers to decay modes with or without additional accompanying decay particles. From the number of signal candidates in the Bpi+- mass spectra of these two samples, we perform the first measurement of the branching ratio of orbitally-excited B mesons decaying into B*pi(X): BR(B*J ->B*pi(X)) = 0.85 +0.36-0.37 +- 0.12, where the first error is statistical and the second systematic. If B*J decay modes other than single pion transitions can be neglected the measured ratio corresponds to the branching ratio BR(B*J->B*pi). In the framework of Heavy Quark Symmetry, a simultaneous fit to the Bpi+- mass spectra of the samples enriched or depleted in B*J->B*pi+-(X) decays yields the mass and the width of the B1(3/2) state, as well as the branching ratio of B*J mesons decaying into B*pi: M(B1(3/2)) = (5.738 +0.005-0.006 +-0.007) GeV/c2 G(B1(3/2)) = (18 +15-13 +29-23) MeV/c BR(B*J->B*pi) = 0.74 +0.12-0.10 +0.21-0.15, where the uncertainties are statistical and systematic, respectively.From about 4 million hadronic Z decays recorded by the OPAL detector on and near to the Z resonance, we select a sample of more than 570000 inclusively reconstructed B mesons. Orbitally-excited mesons B*J are reconstructed using Bpi+- combinations. Independently, B* mesons are reconstructed using the decay B* -> Bgamma. The selected B* candidates are used to obtain samples enriched or depleted in the decay B*J -> B*pi+-(X), where (X) refers to decay modes with or without additional accompanying decay particles. From the number of signal candidates in the Bpi+- mass spectra of these two samples, we perform the first measurement of the branching ratio of orbitally-excited B mesons decaying into B*pi(X): BR(B*J ->B*pi(X)) = 0.85 +0.36-0.37 +- 0.12, where the first error is statistical and the second systematic. If B*J decay modes other than single pion transitions can be neglected the measured ratio corresponds to the branching ratio BR(B*J->B*pi). In the framework of Heavy Quark Symmetry, a simultaneous fit to the Bpi+- mass spectra of the samples enriched or depleted in B*J->B*pi+-(X) decays yields the mass and the width of the B1(3/2) state, as well as the branching ratio of B*J mesons decaying into B*pi: M(B1(3/2)) = (5.738 +0.005-0.006 +-0.007) GeV/c2 G(B1(3/2)) = (18 +15-13 +29-23) MeV/c BR(B*J->B*pi) = 0.74 +0.12-0.10 +0.21-0.15, where the uncertainties are statistical and systematic, respectively
Production of nucleon resonances by single diffraction dissociation at the CERN ISR
No full textThe single diffraction dissociation process pp to (p pi /sup +/ pi /sup -/)p has been studied at the CERN ISR at square root s=45 GeV and 0.1<-t<0.6 GeV/sup 2/. The reaction is dominated by nucleon resonance production: pp to pN(1520) and pp to pN(1688) with cross-sections (0.25+or-0.08) mb and (0.56+or-0.19) mb respectively. (9 refs)
Study of and decays: measurement of the ratio of branching fractions and search for direct CP violation
No full textWe study B^+/- --> J/psi pi^+/- and B^+/- --> J/psi K^+/- decays in a sample of about 89 million BB~ pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. We observe a signal of 244 +/- 20 B^+/- --> J/psi pi^+/- events and determine the ratio BF(B^+/- --> J/psi pi^+/-)/BF(B^+/- --> J/psi K^+/-) to be [5.37 +/- 0.45 (stat.) +/- 0.11 (syst)]%. The charge asymmetries for the B^+/- --> J/psi pi^+/- and B^+/- --> J/psi K^+/- decays are determined to be A_pi = 0.123 +/- 0.085 (stat.) +/- 0.004 (syst.) and A_K = 0.030 +/- 0.015 (stat.) +/- 0.006 (syst.), respectively
Investigation of CP violation in decays at LEP
No full textAn investigation of CP violation was performed using a total of 24 candidates for B^0 -> J/psi K^0_S decay, with a purity of about 60%. These events were selected from 4.4 million hadronic Z^0 decays recorded by the OPAL detector at LEP. An analysis procedure, involving techniques to reconstruct the proper decay times and tag the produced b-flavours, B^0 or B^0(bar), has been developed to allow a first direct study of the time dependent CP asymmetry that, in the Standard Model, is sin(2beta). The result is sin(2beta) = 3.2_{-2.0}^{+1.8} +/- 0.5, where the first error is statistical and the second systematic. This result is used to determine probabilities for different values of sin(2beta) in the physical region from -1 to +1.An investigation of CP violation was performed using a total of 24 candidates for B^0 -> J/psi K^0_S decay, with a purity of about 60%. These events were selected from 4.4 million hadronic Z^0 decays recorded by the OPAL detector at LEP. An analysis procedure, involving techniques to reconstruct the proper decay times and tag the produced b-flavours, B^0 or B^0(bar), has been developed to allow a first direct study of the time dependent CP asymmetry that, in the Standard Model, is sin(2beta). The result is sin(2beta) = 3.2_{-2.0}^{+1.8} +/- 0.5, where the first error is statistical and the second systematic. This result is used to determine probabilities for different values of sin(2beta) in the physical region from -1 to +1
Investigation of CP violation in B0 ---> J / psi K0(S) decays at LEP
No full textContains fulltext :
125068.pdf (Author’s version preprint ) (Open Access)
Contains fulltext :
125068.pdf (Publisher’s version ) (Open Access
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