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Contri, R.

Publications and source records attributed to Contri, R..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Search for a Dark Photon in e + e - Collisions at BaBar

Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the so-called dark photon (A'), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e + e - →γA', A'→e + e - , μ + μ - using 514 fb -1 of data collected with the BABAR detector. We observe no statistically significant deviations from the standard model predictions, and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of10 -4 -10 -3 for dark photon masses in the range 0.02–10.2 GeV We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.

Lees, J. P.↗
DOE OSTI2013

Search for C P Violation in B 0 - B ¯ 0 Mixing Using Partial Reconstruction of B 0 → D * - X ℓ + ν ℓ and a Kaon Tag

We present results of a search for CP violation in B 0 -B¯ 0 mixing with the BABAR detector. We select a sample of B 0 →D* - Xℓ+ν decays with a partial reconstruction method and use kaon tagging to assess the flavor of the other B meson in the event. We determine the CP violating asymmetry ACP≡[N(B 0 B 0 )-N(B¯ 0 B¯ 0 )]/[N(B 0 B 0 )+N(B¯ 0 B¯ 0 )]=(0.06±0.17+0.38-0.32)%, corresponding to ΔCP=1-|q/p|=(0.29±0.84 +1.88 -1.61 )×10 -3 .

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Search for a light Higgs boson decaying to two gluons or ss̄ in the radiative decays of Υ(1S)

We search for the decay Υ(1S)→γA⁰, A⁰→gg or ss̄, where A⁰ is the pseudoscalar light Higgs boson predicted by the next-to-minimal supersymmetric Standard Model. We use a sample of (17.6±0.3)×10⁶ Υ(1S) mesons produced in the BABAR experiment via e⁺e⁻→Υ(2S)→π⁺π⁻Υ(1S). We see no significant signal and set 90%-confidence-level upper limits on the product branching fraction B(Υ(1S)→γA⁰)·B(A⁰→gg or ss̄) ranging from 10⁻⁶ to 10⁻² for A⁰ masses in the range 0.5–9.0 GeV/c².

Lees, J. P.↗