8 research outputs found

    A Search for Dark Higgs Bosons

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    Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs boson using 516 fb-1 of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the Standard Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots for b/w printin

    B0 meson decays to rho0 K*0, f0 K*0, and rho-K*+, including higher K* resonances

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    We present branching fraction measurements for the decays B0 -> rho0 K*0, B0 -> f0 K*0, and B0 -> rho- K*+, where K* is an S-wave (K pi)_0* or a K*(892) meson; we also measure B0 -> f0 K_2*(1430)^0. For the K*(892) channels, we report measurements of longitudinal polarization fractions (for rho final states) and direct CP-violation asymmetries. These results are obtained from a sample of (471.0 +/- 2.8) x 10^6 BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+ e- collider at the SLAC National Accelerator Laboratory. We observe rho0 K*(892)^0, rho0 (K pi)_0^{*0}, f0 K*(892)^0, and rho- K*(892)+ with greater than 5 sigma significance, including systematics. We report first evidence for f0 (K pi)_0^{*0} and f0 K_2*(1430)^0, and place an upper limit on rho- (K pi)_0^{*+}. Our results in the K*(892) channels are consistent with no direct CP-violation.Comment: 17 pages, 6 postscript figures, submitted to Phys. Rev.

    Measurement of BB angular correlations based on secondary vertex reconstruction at ps = 7 TeV

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    35 páginas, 8 figuras, 2 tablas.-- Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License.-- CMS Collaboration: et al.A measurement of the angular correlations between beauty and anti-beauty hadrons (BB) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the rst time the region of small angular separation. The B hadrons are identi ed by the presence of displaced secondary vertices from their decays. The B hadron angular separation is reconstructed from the decay vertices and the primaryinteraction vertex. The di erential BB production cross section, measured from a data sample collected by CMS and corresponding to an integrated luminosity of 3:1 pb-1, shows that a sizable fraction of the BBpairs are produced with small opening angles. These studies provide a test of QCD and further insight into the dynamics of bb production.Acknowledge support from: FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, andHIP (Finland); CEAand CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA).Peer reviewe

    Search for CP violation in the decay τ^{-}→π^{-}K_{s}^{0}(≥Oπ^{0})ν_{τ}

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    We report a search for CP violation in the decay τ-→π-KS0(≥0π0)ντ using a data set of 437×106 τ-lepton pairs, corresponding to an integrated luminosity of 476  fb-1, collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.36±0.23±0.11)% approximately 2.8 standard deviations from the standard model prediction of (0.36±0.01)%

    B0 meson decays to ρ0K∗0, f0K∗0, and ρ−K∗+, including higher K∗ resonances

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    We present branching fraction measurements for the decays B0→ρ0K*0, B0→f0K*0, and B0→ρ-K*+, where K* is an S-wave (Kπ)0* or a K*(892) meson; we also measure B0→f0K2*(1430)0. For the K*(892) channels, we report measurements of longitudinal polarization fractions (for ρ final states) and direct CP violation asymmetries. These results are obtained from a sample of (471.0±2.8)×106 BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. We observe ρ0K*(892)0, ρ0(Kπ)0*0, f0K*(892)0, and ρ-K*(892)+ with greater than 5σ significance, including systematics. We report first evidence for f0(Kπ)0*0 and f0K2*(1430)0, and place an upper limit on ρ-(Kπ)0*+. Our results in the K*(892) channels are consistent with no direct CP violation

    B0 meson decays to rho0 K*0, f0 K*0, and rho-K*+, including higher K* resonances

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    We present branching fraction measurements for the decays B0 -> rho0 K*0, B0 -> f0 K*0, and B0 -> rho- K*+, where K* is an S-wave (K pi)_0* or a K*(892) meson; we also measure B0 -> f0 K_2*(1430)^0. For the K*(892) channels, we report measurements of longitudinal polarization fractions (for rho final states) and direct CP-violation asymmetries. These results are obtained from a sample of (471.0 +/- 2.8) x 10^6 BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+ e- collider at the SLAC National Accelerator Laboratory. We observe rho0 K*(892)^0, rho0 (K pi)_0^{*0}, f0 K*(892)^0, and rho- K*(892)+ with greater than 5 sigma significance, including systematics. We report first evidence for f0 (K pi)_0^{*0} and f0 K_2*(1430)^0, and place an upper limit on rho- (K pi)_0^{*+}. Our results in the K*(892) channels are consistent with no direct CP-violation

    Measurement of W+W- production and search for the Higgs boson in pp collisions at root s=7 TeV

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    A measurement of W+W- production in pp collisions at root s = 7 TeV and a search for the Higgs boson are reported. The W+W- candidates are selected in events with two leptons, either electrons or muons. The measurement is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 36 pb(-1). The pp -> W+W- cross section is measured to be 41.1 +/- 15.3 (stat) +/- 5.8 (syst) +/- 4.5 (lumi) ph. consistent with the standard model prediction. Limits on WW gamma and WWZ anomalous triple gauge couplings are set. The search for the standard model Higgs boson in the W+W- decay mode does not reveal any evidence of excess above backgrounds. Limits are set on the production of the Higgs boson in the context of the standard model and in the presence of a sequential fourth family of fermions with high masses. In the latter context, a Higgs boson with mass between 144 and 207 GeV/c(2) is ruled out at 95% confidence level. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved

    Search for the standard model Higgs boson decaying to a bb¯ pair in events with no charged leptons and large missing transverse energy using the full CDF data set

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    We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at s√=1.96  TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45  fb−1. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a b quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and 150  GeV/c2. For a Higgs boson mass of 125  GeV/c2, the observed (expected) limit is 6.7 (3.6) times the standard model prediction
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