Search for the Lepton-Flavor-Violating Decays B-s(0) -> e(+/-)mu(-/+) and B-0 -> e(+/-)mu(-/+)

A search for the lepton-flavor-violating decays B0s\u2192e\ub1\u3bc 13 and B0\u2192e\ub1\u3bc 13 is performed with a data sample, corresponding to an integrated luminosity of 1.0\u2009\u2009fb 121 of pp collisions at s 1a=7\u2009\u2009TeV, collected by the LHCb experiment. The observed number of B0s\u2192e\ub1\u3bc 13 and B0\u2192e\ub1\u3bc 13 candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be \u212c(B0s\u2192e\ub1\u3bc 13)<1.1(1.4) 710 128 and \u212c(B0\u2192e\ub1\u3bc 13)<2.8(3.7) 710 129 at 90% (95%) confidence level (C.L.). These limits are a factor of 20 lower than those set by previous experiments. Lower bounds on the Pati-Salam leptoquark masses are also calculated, MLQ(B0s\u2192e\ub1\u3bc 13)>101\u2009\u2009TeV/c2 and MLQ(B0\u2192e\ub1\u3bc 13)>126\u2009\u2009TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds

Observation of an exotic narrow doubly charmed tetraquark

Conventional, hadronic matter consists of baryons and mesons made of three quarks and a quark-antiquark pair, respectively(1,2). Here, we report the observation of a hadronic state containing four quarks in the Large Hadron Collider beauty experiment. This so-called tetraquark contains two charm quarks, a (u) over bar and a (d) over tilde quark. This exotic state has a mass of approximately 3,875 MeV and manifests as a narrow peak in the mass spectrum of (DD0)-D-0 pi(+) mesons just below the D*D-+(0) mass threshold. The near-threshold mass together with the narrow width reveals the resonance nature of the state

Constraints on the CKM angle gamma from B-+/- -> Dh(+/-) decays using D -> h(+/-)h'(-/+)pi(0) final states

A data sample collected with the LHCb detector corresponding to an integrated luminosity of 9 fb(-1) is used to measure eleven CP violation observables in B-+/- -> Dh(+/-) decays, where h is either a kaon or a pion. The neutral D meson decay is reconstructed in the three-body final states: K-+/-pi(-/+)pi(0); pi(+)pi(-)pi(0); K+ K- pi(0) and the suppressed pi K-+(-/+)pi(0) combination. The mode where a large CP asymmetry is expected, B-+/- -> [K-+/-pi(-/+)pi(0)] K-D(+/-), is observed with a significance greater than seven standard deviations. The ratio of the partial width of this mode relative to that of the favoured mode, B-+/- -> [K-+/-pi(-/+)pi(0)] K-D(+/-), is R-ADS(K) = (1.27 +/- 0.16 +/- 0.02) x 10(-2). Evidence for a large CP asymmetry is also seen: A(ADS(K)) = - 0.38 +/- 0.12 +/- 0.02. Constraints on the CKM angle gamma are calculated from the eleven reported observables

J Exp Med

To investigate the role of Lyt-2 and Thy-1 in cytolysis, we have generated, by ethyl methanesulfonate mutagenesis and selection, variants of the cloned cytolytic T lymphocyte line L3 that specifically lack either Lyt-2 or Thy-1. An analysis of these variants indicates that neither Lyt-2 nor Lyt-3 is responsible for the lethal hit, but suggests that Lyt-2 and/or Lyt-3 are required for an antigen receptor functional in cytolysis. The data also suggest that the expression of Lyt-3 on the cell surface is not independent of the expression of Lyt-2. Finally the data indicate the Thy-1 plays no role in cytolysis.6788878PMC218609

Measurement of the lepton charge asymmetry in inclusive WW production in pp collisions at s=7\sqrt{s} = 7 TeV

A measurement of the lepton charge asymmetry in inclusive pp to WX production at sqrt(s)= 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. This high precision measurement of the lepton charge asymmetry, performed in both the W to e nu and W to mu nu channels, provides new insights into parton distribution functions.A measurement of the lepton charge asymmetry in inclusive pp to WX production at sqrt(s)= 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. This high precision measurement of the lepton charge asymmetry, performed in both the W to e nu and W to mu nu channels, provides new insights into parton distribution functions.A measurement of the lepton charge asymmetry in inclusive pp to WX production at sqrt(s)= 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. This high precision measurement of the lepton charge asymmetry, performed in both the W to e nu and W to mu nu channels, provides new insights into parton distribution functions