1,730 research outputs found
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E691 Dalitz plot analysis of [Lambda][sub c][sup +] [yields] pK[sup [minus]][pi][sup +] decays
No full textThe resonant decays of the [Lambda][sub c][sup +] can give insight into the weak decay mechanism of this charmed baryon. We have performed a Dalitz plot analysis of the final state for a clean sample [Lambda][sub c][sup +] [yields] pK[sup [minus]][pi][sup +] decays observed in photoproduction experiment E691 at Fermilab. We measure [Gamma](pK*(892)[degrees])/[Gamma] (pK[sup [minus]][pi][sup +]) = .35 [plus minus] .09 [plus minus] .07. We also observe an unexpected enhancement at low pK- invariant mass
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E691 Dalitz plot analysis of {Lambda}{sub c}{sup +} {yields} pK{sup {minus}}{pi}{sup +} decays
No full textThe resonant decays of the {Lambda}{sub c}{sup +} can give insight into the weak decay mechanism of this charmed baryon. We have performed a Dalitz plot analysis of the final state for a clean sample {Lambda}{sub c}{sup +} {yields} pK{sup {minus}}{pi}{sup +} decays observed in photoproduction experiment E691 at Fermilab. We measure {Gamma}(pK*(892){degrees})/{Gamma} (pK{sup {minus}}{pi}{sup +}) = .35 {plus_minus} .09 {plus_minus} .07. We also observe an unexpected enhancement at low pK- invariant mass
CMS pixel detector: Overview
No full textAn overview of the compact muon solenoid pixel detector effort is presented. Pixel detectors are being built for use at the large hadron collider beginning in the year 2007. It is reported that a good progress is made in 2002 on the critical issues of readout chip and token bit manager design, bump bonding and sensor testing. (Edited abstract) 8 Refs
Angular distributions in the decay B -> K*l(+)l(-)
No full textWe use a sample of 384 X 10(6) B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) collider to study angular distributions in the rare decays B -> K(*)l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-). For low dilepton invariant masses, m(ee) 3.2 GeV/c(2), we measure A(FB) = 0.76(-0.32)(+0.52) +/- 0.07 F-L = 0.71(-0.22)(+0.20) +/- 0.04
Search for the rare decays B ---> K l+ l- and B ---> K* l+ l-
No full textWe present results from a search for the flavor-changing neutral current decays B --> Kl(+)l(-) and B --> K*l(+)l(-), where l(+)l(-) is either an e(+)e(-) or mu(+)mu(-) pair. The data sample comprises 22.7 x 10(6) Y (4S) --> BB decays collected with the BABAR detector at the PEP-II B Factory. We obtain the 90% C. L. upper limits B (B --> Kl(+)l(-)) K*l(+)l(-)) Ke(+/-) mu(-/+) and B --> K* e(+/-) mu(-/+)
Search for lepton-number violating B + → X -l + l ′ + decays
No full textWe report on a search for eleven lepton-number violating processes B+→X-l+l′+ with X-=K-, π-, ρ-, K*-, or D- and l+/l′+=e+ or μ+, using a sample of 471±3 million BB̄ events collected with the BABAR detector at the PEP-II e+e- collider at the SLAC National Accelerator Laboratory. We find no evidence for any of these modes and place 90% confidence level upper limits on their branching fractions in the range (1.5-26)×10-7. © 2014 American Physical Society
A Search for the Rare Decays B→πl+l− and B0→ηl+l−
No full textWe present the results of a search for the rare flavor-changing neutral-current decays B --> pi l+l- (pi=pi+/-, pi0 and l = e,mu) and B0 --> eta l+l- using a sample of e+e- --> Y(4S) BB decays decays corresponding to 428 fb^-1 of integrated luminosity collected by the BABAR detector. No significant signal is observed, and we set an upper limit on the isospin and lepton-flavor averaged branching fraction of BF(B --> pi l+l-) eta l+l-) pi+ e+e-, B0 --> pi0 e+e-, B+ --> pi+ mu+mu-, B0 --> pi0 mu+mu-, B0 --> eta e+e-, and B0 --> eta mu+mu-
Direct CP, lepton flavor, and isospin asymmetries in the decays B -> K((*))l(+)l(-)
No full textWe measure branching fractions and integrated rate asymmetries for the rare decays B -> K((*))l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-), using a sample of 384x10(6) BB events collected with the BABAR detector at the PEP-II e(+)e(-) collider. We find no evidence for direct CP or lepton-flavor asymmetries. However, for dilepton masses below the J/psi resonance, we find evidence for unexpectedly large isospin asymmetries in both B -> Kl(+)l(-) and B -> K(*)l(+)l(-) which differ, respectively, by 3.2 sigma and 2.7 sigma, including systematic uncertainties, from the standard model expectations
Model-independent search for the decay B^{+}→l^{+}ν_{l}γ
No full textWe present a search for the radiative leptonic decay B(+)-> l(+)nu(l)gamma, where l=e, mu, using a data sample of 465x10(6) BB pairs collected by the BABAR experiment. In this analysis, we fully reconstruct the hadronic decay of one of the B mesons in Upsilon(4S)-> B(+)B(-) decays, then search for evidence of B(+)-> l(+)nu(l)gamma in the rest of the event. We observe no significant evidence of signal decays and report model-independent branching fraction upper limits of B(B(+)-> e(+)nu(e)gamma)mu(+)nu(mu)gamma) l(+)nu(l)gamma)< 15.6x10(-6) (l=e or mu), all at the 90% confidence level
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