Measurement of the charge asymmetry in semileptonic Bs0 decays
Physical Review Letters 98:15 (2007)
Abstract:
We have performed the first direct measurement of the time-integrated flavor untagged charge asymmetry in semileptonic Bs0 decays ASLs,unt by comparing the decay rate of Bs0→μ+Ds-νX, where Ds- π- and →K+K-, with the charge-conjugate B̄s0 decay rate. This sample was selected from 1.3fb-1 of data collected by the D0 experiment in run II of the Fermilab Tevatron collider. We obtain ASLs,unt=[1.23±0.97(stat)±0. 17(syst)]×10-2. Assuming that Δms/Γ̄s 1, this result can be translated into a measurement of the CP-violating phase in Bs0 mixing: ΔΓs/Δmstan s=[2.45±1.93(stat)±0.35(syst)] ×10-2. © 2007 The American Physical Society.Search for single production of scalar leptoquarks in p over(p, ̄) collisions decaying into muons and quarks with the D0 detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 647:2-3 (2007) 74-81
Abstract:
We report on a search for second generation leptoquarks (LQ2) which decay into a muon plus quark in p over(p, ̄) collisions at a center-of-mass energy of sqrt(s) = 1.96 TeV in the D0 detector using an integrated luminosity of about 300 pb-1. No evidence for a leptoquark signal is observed and an upper bound on the product of the cross section for single leptoquark production times branching fraction β into a quark and a muon was determined for second generation scalar leptoquarks as a function of the leptoquark mass. This result has been combined with a previously published D0 search for leptoquark pair production to obtain leptoquark mass limits as a function of the leptoquark-muon-quark coupling, λ. Assuming λ = 1, lower limits on the mass of a second generation scalar leptoquark coupling to a u quark and a muon are mLQ2 > 274 GeV and mLQ2 > 226 GeV for β = 1 and β = 1 / 2, respectively. © 2007 Elsevier B.V. All rights reserved.Lifetime difference and CP-violating phase in the Bs0 system.
Phys Rev Lett 98:12 (2007) 121801
Abstract:
From an analysis of the decay Bs0-->J/psi phi, we obtain the width difference between the light and heavy mass eigenstates DeltaGamma identical with (GammaL-GammaH)=0.17+/-0.09(stat)+/-0.02(syst) ps-1 and the CP-violating phase phis=-0.79+/-0.56(stat)(-0.01)(+0.14)(syst). Under the hypothesis of no CP violation (phis identical with 0), we obtain 1/Gamma=tau(Bs0)=1.52+/-0.08(stat)(-0.03)(+0.01)(syst) ps and DeltaGamma=0.12(-0.10)(+0.08)(stat)+/-0.02(syst) ps-1. The data sample corresponds to an integrated luminosity of about 1.1 fb-1 accumulated with the D0 detector at the Fermilab Tevatron collider. This is the first direct measurement of the CP-violating mixing phase in the Bs0 system.Lifetime difference and CP-violating phase in the Bs0 system
Physical Review Letters 98:12 (2007)
Abstract:
From an analysis of the decay Bs0→J/ψ, we obtain the width difference between the light and heavy mass eigenstates ΔΓ(ΓL- ΓH)=0.17±0.09(stat)±0.02(syst)ps-1 and the CP-violating phase s=-0.79±0.56(stat)-0.01+0.14(syst). Under the hypothesis of no CP violation (0), we obtain 1/Γ̄=τ̄(Bs0)=1.52±0.08(stat) -0.03+0.01(syst)ps and ΔΓ=0.12-0.10+0.08(stat)±0.02(syst)ps- 1. The data sample corresponds to an integrated luminosity of about 1.1fb-1 accumulated with the D0 detector at the Fermilab Tevatron collider. This is the first direct measurement of the CP-violating mixing phase in the Bs0 system. © 2007 The American Physical Society.Search for the pair production of scalar top quarks in the acoplanar charm jet final state in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 645:2-3 (2007) 119-127