747 research outputs found
Measurements of b → sγ Decays at BABAR
No full textWe present measurements of the Branching Fraction and photon energy spectrum in
b → X_sγ decays in a sample of 89 million BB[overbar] pairs collected at the BABAR detector at Stanford
Linear Accelerator Center's PEP-II asymmetric B-factory. Results from a fully-inclusive and a sum
of 38 exclusive final states techniques are presented and found to be consistent with the Standard
Model calculations, as well as experimental results obtained from semileptonic b → X_clv decays
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Measurements of b to s gamma Decays at BaBar
No full textWe present measurements of the Branching Fraction and photon energy spectrum in B {yields} X{sub S}{gamma} decays in a sample of 89 million B{bar B} pairs collected at the BABAR detector at Stanford Linear Accelerator Center's PEP-II asymmetric B-factory. Results from a fully-inclusive and a sum of 38 exclusive final states techniques are presented and found to be consistent with the Standard Model calculations, as well as experimental results obtained from semileptonic B {yields} X{sub c}lv decays
Search for CP violation using T-odd correlations in D-0 -> K+K-pi(+)pi(-) decays
No full textWe search for CP violation in a sample of 4.7 x 10(4) Cabibbo suppressed D-0 -> K+K-pi(+)pi(-) decays. We use 470 fb(-1) of data recorded by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) storage rings running at center-of-mass energies near 10.6 GeV. CP violation is searched for in the difference between the T-odd asymmetries, obtained using triple product correlations, measured for D-0 and (D) over bar (0) decays. The measured CP violation parameter is A(T) = (1.0 +/- 5.1(stat) +/- 4.4(syst)) x 10(-3)
Search for T, CP, and CPT violation in B-0-(B)over-bar(0) mixing with inclusive dilepton events
No full textWe report the results of a search for T, CP, and CPT violation in (B) over bar (0)-(B) over bar (0) mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B factory. Using a sample of 232x10(6) B (B) over bar pairs, we measure the T and CP violation parameter vertical bar q/p vertical bar-1=(-0.8 +/- 2.7(stat)+/- 1.9(syst))x10(-3), and the CPT and CP parameters Imz=(-13.9 +/- 7.3(stat)+/- 3.2(syst))x10(-3) and Delta Gamma xRez=(-7.1 +/- 3.9(stat)+/- 2.0(syst))x10(-3) ps(-1). The statistical correlation between the measurements of Imz and Delta Gamma xRez is 76%
Limits on the decay-rate difference of neutral B mesons and on CP, T, and CPT violation in B0B0 oscillations
No full textUsing events in which one of two neutral B mesons from the decay of an Υ(4S) resonance is fully reconstructed, we set limits on the difference between the decay rates of the two neutral B mass eigenstates and on CP, T, and CPT violation in B0B0 mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million Υ(4S)→BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations (Δm,ΔΓ/Γ), CPT and CP violation (Rez,Imz), and CP and T violation (ImλCP,|q/p|), where λCP characterizes B0 and B0 decays to states of charmonium plus KS0 or KL0. The results are sgn(ReλCP)ΔΓ/Γ=-0.008±0.037(stat.)±0.018(syst.)[-0.084,0.068],|q/p|=1.029±0.013(stat.)±0.011(syst.)[1.001,1.057],(ReλCP/|λCP|)Rez=0.014±0.035(stat.)±0.034(syst.)[-0.072,0.101],Imz=0.038±0.029(stat.)±0.025(syst.)[-0.028,0.104].The values inside square brackets indicate the 90% confidence-level intervals. The values of ImλCP and Δm are consistent with previous analyses and are used as cross checks. These measurements are in agreement with standard model expectations
Inclusive Λ_c^+ production in e^+e^- annihilations at √s=10.54 GeV and in Υ(4S) decays
No full textWe present measurements of the total production rates and momentum distributions of the charmed baryon Λ_c^+ in e^+e^-→hadrons at a center-of-mass energy of 10.54 GeV and in Υ(4S) decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in e^+e^-→cc[overbar] events, allowing direct studies of c-quark fragmentation. We measure a momentum distribution for Λ_c^+ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of =0.574±0.009 and a total rate of N_(Λc)^(qq[overbar]) =0.057±0.002(exp)±0.015(BF) Λ_c^+ per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, pK^-π^+. In Υ(4S) decays we measure a total rate of N_(Λc)^Υ=0.091±0.006(exp)±0.024(BF) per Υ(4S) decay, and find a much softer momentum distribution than expected from B decays into a Λ_c^+ plus an antinucleon and one to three pions
Measurement of branching fractions of B decays to K_1(1270)π and K_1(1400)π and determination of the CKM angle α from B^0→a_1(1260)^±π^∓
No full textWe report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K_1(1270) or K_1(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454×10^6 BB̅ pairs produced in e^+e^- annihilation. We measure the branching fractions B(B^0→K_1(1270)^+π-+K_1(1400)^+π-)=3.1_(-0.7)^(+0.8)×10^(-5) and B(B^+→K_1(1270)^0π^++K_1(1400)^0π^+)=2.9_(-1.7)^(+2.9)×10^(-5) (<8.2×10^(-5) at 90% confidence level), where the errors are statistical and systematic combined. The B^0 decay mode is observed with a significance of 7.5σ, while a significance of 3.2σ is obtained for the B^+ decay mode. Based on these results, we estimate the weak phase α=(79±7±11)° from the time-dependent CP asymmetries in B^0→a1(1260)^±π^∓ decays
Search for the decay B^+ → τ^+ν_τ
No full textWe search for the rare leptonic decay B^+ → τ^+ν_τ in a sample of 232 × 10^6 BB̅ pairs collected with the BABAR detector at the SLAC PEP-II B-Factory. Signal events are selected by examining the properties of the B meson recoiling against the semileptonic decay B^- → D^9*0)ℓ^-ν̅_ ℓ. We find no evidence for a signal and set an upper limit on the branching fraction of B(B^+ → τ^+ν_τ)<2.8 × 10^9-4) at the 90% confidence level. We combine this result with a previous, statistically independent BABAR search for B+→τ+ντ to give an upper limit of B(B^+ → τ^+ν_τ)<2.6 × 10^(-4) at the 90% confidence level
Study of the D_(sJ)^*(2317)^+ and D_(sJ)(2460)^+ mesons in inclusive cc̅ production near √s=10.6 GeV
No full textA study of the D_(sJ)^*(2317)^+ and D_(sJ)(2460)^+ mesons in inclusive cc production is presented using 232 fb^(-1) of data collected by the BABAR experiment near √s=10.6 GeV. Final states consisting of a D_s^+ meson along with one or more π^0, π^±, or γ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the D_(s1)(2536)^+ meson. A search is also performed for neutral and doubly charged partners of the D_(sJ)^*(2317)^+ meson
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