Measurement of the lifetime of the Bc± meson in the semileptonic decay channel
Physical Review Letters 102:9 (2009)
Abstract:
Using approximately 1.3fb-1 of data collected by the D0 detector between 2002 and 2006, we measure the lifetime of the Bc± meson in the Bc±→J/ψμ±+X final state. A simultaneous unbinned likelihood fit to the J/ψ+μ invariant mass and lifetime distributions yields a signal of 881±80(stat) candidates and a lifetime measurement of τ(Bc±)=0.448-0.036+0.038(stat)±0.032(syst)ps. © 2009 The American Physical Society.Measurement of the semileptonic branching ratio of B_{s};{0} to an orbitally excited D_{s};{**} state: Br(B_{s};{0}-->D_{s1};{-}(2536)mu;{+}nuX).
Phys Rev Lett 102:5 (2009) 051801
Abstract:
In a data sample of approximately 1.3 fb;{-1} collected with the D0 detector between 2002 and 2006, the orbitally excited charm state D_{s1};{+/-}(2536) has been observed with a measured mass of 2535.7+/-0.6(stat)+/-0.5(syst) MeV/c;{2} via the decay mode B_{s};{0}-->D_{s1};{-}(2536)mu;{+}nu_{mu}X. A first measurement is made of the branching ratio product Br(b[over ]-->D_{s1};{-}(2536)mu;{+}nu_{mu}X)xBr(D_{s1};{-}-->D;{*-}K_{S};{0}). Assuming that D_{s1};{-}(2536) production in semileptonic decay is entirely from B_{s};{0}, an extraction of the semileptonic branching ratio Br(B_{s};{0}-->D_{s1};{-}(2536)mu;{+}nu_{mu}X) is made.Measurement of the semileptonic branching ratio of Bs0 to an orbitally excited Ds** state: Br(Bs0→Ds1-(2536)μ+νX)
Physical Review Letters 102:5 (2009)
Abstract:
In a data sample of approximately 1.3fb-1 collected with the D0 detector between 2002 and 2006, the orbitally excited charm state Ds1±(2536) has been observed with a measured mass of 2535.7±0.6(stat)±0.5(syst) MeV/c2 via the decay mode Bs0→Ds1-(2536)μ+νμX. A first measurement is made of the branching ratio product Br(b̄→Ds1-(2536) μ+νμX)×Br(Ds1-→D*-KS0). Assuming that Ds1-(2536) production in semileptonic decay is entirely from Bs0, an extraction of the semileptonic branching ratio Br(Bs0→Ds1-(2536)μ+νμX) is made. © 2009 The American Physical Society.Search for a scalar or vector particle decaying into Zγ in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 671:3 (2009) 349-355
Abstract:
We present a search for a narrow scalar or vector resonance decaying into Zγ with a subsequent Z boson decay into a pair of electrons or muons. The data for this search were collected with the DØ detector at the Fermilab Tevatron p over(p, ̄) collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0) fb-1 of data, we observe 49 (50) candidate events in the electron (muon) channel, in good agreement with the standard model prediction. From the combination of both channels, we derive 95% C.L. upper limits on the cross section times branching fraction (σ × B) into Zγ. These limits range from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/ c2 to 2.5 (3.1) pb for a mass of 140 GeV/ c2.Erratum to: "Search for particles decaying into a Z boson and a photon in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV" [Phys. Lett. B 641 (2006) 415] (DOI:10.1016/j.physletb.2006.08.079)
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 670:4-5 (2009) 455-458