2,105 research outputs found
Search for CPT and Lorentz Violation in B0-B̅ 0 Oscillations with Dilepton Events
No full textWe report results of a search for CPT and Lorentz violation in B0-B̅ 0 oscillations using inclusive dilepton events from 232×106 Υ(4S)→BB̅ decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8σ significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth’s sidereal frequency and extract values for the quantities Δaμ in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr-1 to 2.1 solar day-1 are also compatible with no signal
Measurement of the Absolute Branching Fraction of D0→K-π+
No full textWe measure the absolute branching fraction for D0→K-π+ using partial reconstruction of B̅ 0→D*+Xl-ν̅ l decays, in which only the charged lepton and the pion from the decay D*+→D0π+ are used. Based on a data sample of 230×106 BB̅ pairs collected at the Υ(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we obtain B(D0→K-π+)=(4.007±0.037±0.072)%, where the first uncertainty is statistical and the second is systematic
Measurement of the Branching Fractions of Exclusive B̅ →D(*)(π)l-ν̅ l Decays in Events with a Fully Reconstructed B Meson
No full textSearch for the Rare Decay B-> K nu nu-bar
No full textWe present a search for the rare decays B+→K+νν̅ and B0→K0νν̅ using 459×106 BB̅ pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as these are forbidden at tree level but can occur through one-loop diagrams in the standard model (SM), with possible contributions from new physics at the same order. The presence of two neutrinos in the final state makes identification of signal events challenging, so reconstruction in the semileptonic decay channels B→D(*)lν of the B meson recoiling from the signal B is used to suppress backgrounds. We set an upper limit at the 90% confidence level (CL) of 1.3×10-5 on the total branching fraction for B+→K+νν̅ , and 5.6×10-5 for B0→K0νν̅ . We additionally report 90% CL upper limits on partial branching fractions in two ranges of dineutrino mass squared for B+→K+νν
- …
