G. Rong

Evidence for B{sup 0}{yields}{rho}{sup 0}{rho}{sup 0} Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angle {alpha}

We search for the decays B0->rho0rho0, B0->rho0f0, and B0->f0f0 in a sample of about 348 million Upsilon(4S)->BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find evidence for B0->rho0rho0 with 3.0 sigma significance and measure the branching fraction B = (1.16 +0.37-0.36 +-0.27) 10^{-6} and longitudinal polarization fraction f_L = 0.86 +0.11-0.13 +-0.05. As a consequence, the uncertainty on the CKM unitarity angle alpha due to penguin contributions in B->rhorho decays is estimated to be 18 degrees at 1 sigma level. We also set upper limits on the B0->rho0f0 and B0->f0f0 decay rates. All results are preliminary.

Measurement of CP Violation Parameters with a Dalitz Plot Analysis of B{sup {+-}}{yields}D{sub {pi}{sup +}}{sub {pi}{sup -}}{sub {pi}{sup 0}}K{sup {+-}}

We report the results of a CP violation analysis of the decay B{sup {+-}}{yields}D{sub {pi}{sup +}}{sub {pi}{sup -}}{sub {pi}{sup 0}}K{sup {+-}}, where D{sub {pi}{sup +}}{sub {pi}{sup -}}{sub {pi}{sup 0}} indicates a neutral D meson detected in the final state {pi}{sup +}{pi}{sup -}{pi}{sup 0}, excluding K{sub S}{sup 0}{pi}{sup 0}. The analysis makes use of 324x10{sup 6} e{sup +}e{sup -}{yields}BB events recorded by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring. Analyzing the {pi}{sup +}{pi}{sup -}{pi}{sup 0} Dalitz plot distribution and the B{sup {+-}}{yields}D{sub {pi}{sup +}}{sub {pi}{sup -}}{sub {pi}{sup 0}}K{sup {+-}} branching fraction and decay rate asymmetry, we find the following one-standard-deviation constraints on the amplitude ratio and on the weak and strong phases: 0.06<r{sub B}<0.78, -30 deg. <{gamma}<76 deg., -27 deg. <{delta}<78 deg. We also measure the magnitudes and phases of the components of the D{sup 0}{yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0} decay amplitude.

Observation of Decays B{sup 0}{yields}D{sub s}{sup (*)+}{pi}{sup -} and B{sup 0}{yields}D{sub s}{sup (*)-}K{sup +}

We report the observation of decays B{sup 0}{yields}D{sub s}{sup (*)+}{pi}{sup -} and B{sup 0}{yields}D{sub s}{sup (*)-}K{sup +} in a sample of 230x10{sup 6} {upsilon}(4S){yields}BB events recorded with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. We measure the branching fractions B(B{sup 0}{yields}D{sub s}{sup +}{pi}{sup -})=(1.3{+-}0.3(stat){+-}0.2(syst))x10{sup -5}, B(B{sup 0}{yields}D{sub s}{sup -}K{sup +})=(2.5{+-}0.4(stat){+-}0.4(syst))x10{sup -5}, B(B{sup 0}{yields}D{sub s}*{sup +}{pi}{sup -})=(2.8{+-}0.6(stat){+-}0.5(syst))x10{sup -5}, and B(B{sup 0}{yields}D{sub s}*{sup -}K{sup +})=(2.0{+-}0.5(stat){+-}0.4(syst))x10{sup -5}. The significances of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively. This is the first observation of B{sup 0}{yields}D{sub s}{sup +}{pi}{sup -}, B{sup 0}{yields}D{sub s}*{sup +}{pi}{sup -}, and B{sup 0}{yields}D{sub s}*{sup -}K{sup +} decays.

Evidence for the Rare Decay B{sup +}{yields}D{sub s}{sup +}{pi}{sup 0}

We have searched for the rare decay B{sup +}{yields}D{sub s}{sup +}{pi}{sup 0}. The analysis is based on a sample of 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the SLAC PEP-II e{sup +}e{sup -} storage ring. We find 19.6 signal events, corresponding to a significance of 4.7{sigma}. The extracted signal yield including statistical and systematic uncertainties is 20.1{sub -6.0-1.5}{sup +6.8+0.4}, and we measure B(B{sup +}{yields}D{sub s}{sup +}{pi}{sup 0})=(1.5{sub -0.4}{sup +0.5}{+-}0.1{+-}0.2)x10{sup -5}, where the first uncertainty is statistical, the second is systematic, and the last is due to the uncertainty on the D{sub s}{sup +} decay and its daughter decay branching fractions.

Measurements of CP-Violating Asymmetries in B{sup 0}{yields}a{sub 1}{sup {+-}}(1260){pi}{sup {+-}} Decays

The authors present measurements of the time-dependent CP-violating asymmetries in B{sup 0} {yields} K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0} decays based on 384 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. They obtain the CP asymmetry parameters C = 0.02 {+-} 0.21 {+-} 0.05 and S = -0.71 {+-} 0.24 {+-} 0.04, where the first uncertainties are statistical and the second systematic. These results are consistent with standard model expectations.

Search for Lepton Flavor Violating Decays {tau}{sup {+-}}{yields}l{sup {+-}}{pi}{sup 0}, l{sup {+-}}{eta}, l{sup {+-}}{eta}{sup '}

A search for lepton flavor violating decays of the {tau} lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb{sup -1} of e{sup +}e{sup -} annihilation data collected at a center-of-mass energy near 10.58 GeV by the BABAR detector at the SLAC PEP-II storage ring. No evidence of a signal has been found, and upper limits on the branching fractions are set at the 10{sup -7} level.A search for lepton flavor violating decays of the tau lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb;{-1} of e;{+}e;{-} annihilation data collected at a center-of-mass energy near 10.58 GeV by the BABAR detector at the SLAC PEP-II storage ring. No evidence of a signal has been found, and upper limits on the branching fractions are set at the 10;{-7} level.

Search for the reactions e{sup +}e{sup -}{yields}{mu}{sup +}{tau}{sup -} and e{sup +}e{sup -}{yields}e{sup +}{tau}{sup -}

We report on a search for the lepton-flavor-violating processes e+e- -> mu+ tau- and e^+e^- -> e+ tau-. The data sample corresponds to an integrated luminosity of 211 fb

Measurement of CP asymmetry in B{sup 0}{yields}K{sub s}{sup 0}{pi}{sup 0}{pi}{sup 0} decays

^{-1}

Measurements of {lambda}{sub c}{sup +} branching fractions of Cabibbo-suppressed decay modes involving {lambda} and {sigma}{sup 0}

recorded by the BaBar experiment at the SLAC PEP-II asymmetric-energy B Factory at a center-of-mass energy of

Branching fraction measurement of B{sup 0}{yields}D{sup (*)+}{pi}{sup -} and B{sup -}{yields}D{sup (*)0}{pi}{sup -} and isospin analysis of B{yields}D{sup (*)}{pi} decays

\sqrt{s} = 10.58