0000000000113508
AUTHOR
Y. G. Kolomensky
Observation of an Excited Charm BaryonΩc*Decaying toΩc0γ
We report the first observation of an excited singly-charm baryon OmegaC* (css) in the radiative decay OmegaC0 Gamma, where the OmegaC0 baryon is reconstructed in the decays to the final states Omega-pi+, Omega-pi+pi0, Omega-pi+pi-pi+, and Cascade-K-pi+pi+. This analysis is performed using a dataset of 230.7 fb$-1} collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The mass difference between the OmegaC* and the OmegaC0 baryons is measured to be 70.8 +/- 1.0 (stat) +/- 1.1 (syst) MeV/c2. We also measure the ratio of inclusive production cross sections of OmegaC* and OmegaC0 in e+e- annihilation.
Measurement of the Inclusive Charmless Semileptonic Branching Ratio ofBMesons and Determination of|Vub|
We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)…
Search for Radiative Penguin DecaysB+→ρ+γ,B0→ρ0γ, andB0→ωγ
A search for the decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782) is performed on a sample of 211 million {Upsilon}(4S) {yields} B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 1.8 x 10{sup -6}, {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 0.4 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at the 90% confidence level (C.L.). We use the quark model to limit the combined branching fraction {bar {Beta}}[B {yields} ({rho}/{omega})…
Limits on the decay-rate difference of neutralBmesons and onCP,T, andCPTviolation inB0B0oscillations
Using events in which one of two neutral-B mesons from the decay of an {Upsilon}(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 B{sup 0}{bar B}{sup 0} mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations ({Delta}m, {Delta}{Lambda}/{Lambda}), CPT and CP violation (Re z, Im z), and CP and T violation (Im {lambda}{sub CP}, |q/p|), where {la…
Search for the DecayB+→K+νν¯
We search for the rare flavor-changing neutral-current decay ${B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in a data sample of $82\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II $B$-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-$B$ decay. Using these two independent samples we obtain a combined limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})l5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In addition, by…
Measurement of theB→πlνBranching Fraction and Determination of|Vub|with TaggedBMesons
We report a measurement of the B ->pi center dot nu branching fraction based on 211 fb(-1) of data collected with the BABAR detector. We use samples of B-0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B-0 ->pi(-)center dot(+)nu)=(1.33 +/- 0.17(stat)+/- 0.11(syst))x10(-4). We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find vertical bar V-ub …
Measurement of the Branching Fraction and Photon Energy Moments ofB→XsγandACP(B→Xs+dγ)
The photon spectrum in B -> X-s gamma decay, where X-s is any strange hadronic state, is studied using a data sample of 88.5x10(6) e(+)e(-)->Upsilon(4S)-> B(B) over bar decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, Delta B(B -> X-s gamma)=(3.67 +/- 0.29(stat)+/- 0.34(syst)+/- 0.29(model))x10(-4), the first moment =2.288 +/- 0.025 +/- 0.017 +/- 0.015 GeV, and the second moment =0.0328 +/- 0.0040 +/- 0.0023 +/- 0.0036 GeV2 are measured for the photon energy range 1.9 GeV 1.6 GeV. In addition, the direct CP asymmetry A(CP)(B -> Xs+d gamma) is measured to be -0.110 +/- 0.115(stat)+/- 0.017(syst).
Measurement of branching fractions and rate asymmetries in the rare decays B -> K((*))l(+)l(-)
In a sample of 471 million BB events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B -> K(*) l+ l-, where l+ l- is either e+e- or mu+mu-. We report results on partial branching fractions and isospin asymmetries in seven bins of di-lepton mass-squared. We further present CP and lepton-flavor asymmetries for di-lepton masses below and above the J/psi resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.
Limits onD0−D¯0Mixing andCPViolation from the Ratio of Lifetimes for Decay toK−π+,K−K+, andπ−π+
We present a measurement of D0-macro D0 mixing parameters using the ratios of lifetimes extracted from samples of D0 mesons decaying to K-pi(+), K-K+, and pi(-)pi(+). Using 91 fb(-1) of data collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, we obtain a value Y=[0.8+/-0.4(stat.)(+0.5)(-0.4)(syst.)]%, which, in the limit of CP conservation, corresponds to the mixing parameter y=Delta Gamma/2 Gamma. Using the difference in lifetimes of D0 and macro D0 mesons, we obtain the CP-violation parameter Delta Y=[-0.8+/-0.6(stat.)+/-0.2(syst.)]%.
Measurements of the Absolute Branching Fractions of B± →k±Xc c
A study of the two-body decays B±→XccK±, where Xcc refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fb-1. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B+→X(3872)K+ at the 3σ level. The absolute branching fraction B[B+→X(3872)K+]=[2.1±0.6(stat)±0.3(syst)]×10-4 is measured for the first time. It follows that B[X(3872)→J/ψπ+π-]=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.
Observation of the DecayB±→π±π0, Study ofB±→K±π0, and Search forB0→π0π0
We present results for the branching fractions and charge asymmetries in B+/--->h(+/-)pi(0) (where h(+/-)=pi(+/-),K+/-) and a search for the decay B0-->pi(0)pi(0) using a sample of approximately 88 x 10(6) BBmacr; pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure B(B+/--->pi(+/-)pi(0))=(5.5(+1.0)(-0.9)+/-0.6)x10(-6), where the first error is statistical and the second is systematic. The B+/--->pi(+/-)pi(0) signal has a significance of 7.7sigma including systematic uncertainties. We simultaneously measure the K+/-pi(0) branching fraction to be B(B+/--->K+/-pi(0))=(12.8(+1.2)(-1.1)+/-1.0)x10(-6). The charge asymmetries are Api(+/-)(pi(0))=-0.0…
Precision Measurement of the Ratio B(ϒ(3S)→τ+τ−)/B(ϒ(3S)→μ+μ−)
We report on a precision measurement of the ratio ${\cal R}_{\tau\mu}^{\Upsilon(3S)} = {\cal B}(\Upsilon(3S)\to\tau^+\tau^-)/{\cal B}(\Upsilon(3S)\to\mu^+\mu^-)$ using data collected with the BaBar detector at the SLAC PEP-II $e^+e^-$ collider. The measurement is based on a 28 fb$^{-1}$ data sample collected at a center-of-mass energy of 10.355 GeV corresponding to a sample of 122 million $\Upsilon(3S)$ mesons. The ratio is measured to be ${\cal R}_{\tau\mu}^{\Upsilon(3S)} = 0.966 \pm 0.008_\mathrm{stat} \pm 0.014_\mathrm{syst}$ and is in agreement with the Standard Model prediction of 0.9948 within 2 standard deviations. The uncertainty in ${\cal R}_{\tau\mu}^{\Upsilon(3S)}$ is almost an o…