Evidence for the decay D0-->K(-)pi(+)pi(-)e(+)nu(e)

Using a 281 pb{-1} data sample collected at the psi(3770) with the CLEO-c detector, we present the first absolute branching fraction measurement of the decay D0-->K(-)pi(+)pi(-)e(+)nu(e) at a statistical significance of about 4.0 standard deviations. We find 10 candidates consistent with the decay D0-->K(-)pi(+)pi(-)e(+)nu(e). The probability that a background fluctuation accounts for this signal is less than 4.1 x 10{-5}. We find B(D0-->K(-)pi(+)pi(-)e(+)nu(e)) = [2.8{-1.1}{+1.4}(stat)+/-0.3(syst)]x10{-4}. By restricting the invariant mass of the hadronic system to be consistent with K1(1270), we obtain the product of branching fractions B(D{0}-->K{1}{-}(1270)e{+}nu{e})xB(K1-(1270)-->K{-}pi{+}pi{-})=[2.5{-1.0}{+1.3}(stat)+/-0.2(syst)]x10{-4}. Using B(K1-(1270)-->K{-}pi{+}pi{-})=(33+/-3)%, we obtain B(D{0}-->K{1}{-}(1270)e{+}nu{e})=[7.6{-3.0}{+4.1}(stat)+/-0.6(syst)+/-0.7]x10{-4}. The last error accounts for the uncertainties in the measured K1-(1270)-->K{-}pi{+}pi{-} branching fractions.     

Observation of decays B0-->Ds(*)+ pi- and B0-->Ds(*)- K+

We report the observation of decays B{0}-->D{s}{(*)+}pi- and B{0}-->D{s}{(*)-}K+ in a sample of 230 x 10(6) Upsilon(4S)-->BB[over] events recorded with the BABAR detector at the SLAC PEP-II asymmetric-energy e+ e- storage ring. We measure the branching fractions B(B{0}-->D{s}{+}pi-)=(1.3+/-0.3(stat)+/-0.2(syst))x10(-5), B(B{0}-->D{s}{-} K+)=(2.5+/-0.4(stat)+/-0.4(syst))x10(-5), B(B{0}-->D{s}{*+}pi-)=(2.8+/-0.6(stat)+/-0.5(syst))x10(-5), and B(B{0}-->D{s}{*-}K+)=(2.0+/-0.5(stat)+/-0.4(syst))x10(-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{0}-->D{s}{+}pi-, B{0}-->D{s}{*+}pi-, and B{0}-->D{s}{*-}K+ decays.     

Observation of B(0)-->D(*-)tau(+)nu(tau) decay at Belle

We report an observation of the decay B{0}-->D{*-}tau{+}nu{tau} in a data sample containing 535x10{6} BB pairs collected with the Belle detector at the KEKB asymmetric-energy e{+}e{-} collider. We find a signal with a significance of 5.2sigma and measure the branching fraction B(B{0}-->D{*-}tau{+}nu{tau})=(2.02{-0.37}{+0.40}(stat)+/-0.37(syst))%. This is the first observation of an exclusive B decay with a b-->ctaunu{tau} transition.     

Measurement of the ratios of branching fractions B(B0s --> Ds- pi+ pi+ pi-)/B(B0-->D- pi+ pi+ pi-) and B(B0s --> Ds- pi+)/B(B0-->D- pi+)

Using 355 pb;{-1} of data collected by the CDF II detector in pp[over ] collisions at sqrt[s]=1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B_{(s)};{0}-->D_{(s)};{-}pi;{+} and B_{(s)};{0}-->D_{(s)};{-}pi;{+}pi;{+}pi;{-}. We present the first measurement of the ratio of branching fractions B(B_{s};{0}-->D_{s};{-}pi;{+}pi;{+}pi;{-})/B(B;{0}-->D;{-}pi;{+}pi;{+}pi;{-})=1.05+/-0.10(stat)+/-0.22(syst). We also update our measurement of B(B_{s};{0}-->D_{s};{-}pi;{+})/B(B;{0}-->D;{-}pi;{+}) to 1.13+/-0.08(stat)+/-0.23(syst), improving the statistical uncertainty by more than a factor of 2. We find B(B_{s};{0}-->D_{s};{-}pi;{+})=[3.8+/-0.3(stat)+/-1.3(syst)]x10;{-3} and B(B_{s};{0}-->D_{s};{-}pi;{+}pi;{+}pi;{-})=[8.4+/-0.8(stat)+/-3.2(syst)]x10;{-3}.     

Suppressed decays of D(s)(+) mesons to two pseudoscalar mesons

Using data collected near the D{s}{*+}D{s}{-} peak production energy E_{cm}=4170 MeV by the CLEO-c detector, we study the decays of D{s}{+} mesons to two pseudoscalar mesons. We report on searches for the singly Cabibbo-suppressed D{s}{+} decay modes K{+}eta, K{+}eta', pi{+}K{S}{0}, K{+}pi{0}, and the isospin-forbidden decay mode D{s}{+}-->pi{+}pi{0}. We normalize with respect to the Cabibbo-favored D{s}{+} modes pi{+}eta, pi{+}eta', and K{+}K{S}{0}, and obtain ratios of branching fractions: B(D{s}{+}-->K{+}eta)/B(D{s}{+}-->pi{+}eta)=(8.9+/-1.5+/-0.4)%, B(D{s}{+}-->K{+}eta')/B(D{s}{+}-->pi{+}eta')=(4.2+/-1.3+/-0.3)%, B(D{s}{+}-->pi{+}K{S}{0})/B(D{s}{+}-->K{+}K{S}{0})=(8.2+/-0.9+/-0.2)%, B(D{s}{+}-->K{+}pi{0})/B(D{s}{+}-->K{+}K{S}{0})=(5.5+/-1.3+/-0.7)%, and B(D{s}{+}-->pi{+}pi{0})/B(D{s}{+}-->K{+}K{S}{0})<4.1% at 90% C.L., where the uncertainties are statistical and systematic, respectively.     

First observation of K{L}-->pi{+/-}e{-/+}nue{+}e{-}

This Letter is the first report of the K{L}-->pi{+/-}e{-/+}nue{+}e{-} decay. Based on 19 208+/-144 events, we determine the branching fraction, B(K{L}-->pi{+/-}e{-/+}nue{+}e{-}M_{e{+}e{-}}>5 MeV/c{2},E{e{+}e{-}}{*}>30 MeV)=(1.285+/-0.041)x10{-5}, and Gamma(K{e3ee}M{e{+}e{-}}>5 MeV/c{2})/Gamma(K{e3})=[4.57+/-0.04(stat)+/-0.14(syst)]x10{-5}. This ratio agrees with a theoretical prediction based on chiral perturbation theory (ChPT) calculated to O(p{4}). The measured kinematical distributions agree with those predicted by just ChPT O(p{4}), but show significant disagreement with ones predicted by leading-order ChPT.     

Observation of the decay B+ --> K+K-pi+

We report the observation of charmless hadronic decays of charged B mesons to the final state K{+}K{-}pi{+}. Using a data sample of 347.5 fb{-1} collected at the Upsilon(4S) resonance with the BABAR detector, we observe 429+/-43 signal events with a significance of 9.6sigma. We measure the inclusive branching fraction B(B{+}-->K{+}K{-}pi{+})=[5.0+/-0.5(stat)+/-0.5(syst)]x10{-6}. Inspection of the Dalitz plot of signal candidates shows a broad structure peaking near 1.5 GeV/c{2} in the K+K- invariant mass distribution. We find the direct CP asymmetry to be consistent with zero.     

Observation of B{0}-->ppK*0 with a large K*0 polarization

Using a 492 fb{-1} data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{+}e{-} collider, we observe the decay B{0}-->ppK*0 with a branching fraction of (1.18{-0.25}{+0.29}(stat)+/-0.11(syst))x10{-6}. We study the decay dynamics of B{0}-->ppK*0 and compare with B{+}-->ppK*+. The K*0 meson is found to be almost 100% polarized (with a fraction of (101+/-13+/-3)% in the helicity zero state), while the K*+ meson has a (32+/-17+/-9)% fraction in the helicity zero state. The direct CP asymmetries for B{0}-->ppK*0 and B{+}-->ppK*+ are measured to be -0.08+/-0.20+/-0.02 and -0.01+/-0.19+/-0.02, respectively. In addition, we report improved measurements of the branching fractions B(B{+}-->ppK*+)=(3.38{-0.60}{+0.73}+/-0.39)x10{-6} and B(B{0}-->ppK{0})=(2.51{-0.29}{+0.35}+/-0.21)x10{-6}, which supersede our previous measurements.     

Search for pi(0)-->nu(mu)nu(mu) decays in the LSND detector

We observe a net beam excess of 8.7+/-6.3(stat)+/-2.4(syst) events, above 160 MeV, resulting from the charged-current reaction of nu(micro) and/or nu;(mu) on C and H in the LSND detector. No beam-related muon background is expected in this energy regime. Within an analysis framework of pi(0)-->nu(mu)nu;(mu), we set a direct upper limit for this branching ratio of Gamma(pi(0)-->nu(mu)nu;(mu))/Gamma(pi(0)-->all)<1.6 x 10(-6) at 90% confidence level.     

Measurement of the branching fraction and CP content for the decay B0-->D(*+)D(*-)

We report a measurement of the branching fraction of the decay B0-->D(*+)D(*-) and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4 fb (-1) collected at the Upsilon(4S) resonance during 1999-2000, we have reconstructed 38 candidate signal events in the mode B0-->D(*+)D(*-) with an estimated background of 6.2+/-0.5 events. From these events, we determine the branching fraction to be B(B0-->D(*+)D(*-))=[8.3+/-1.6(stat)+/-1.2(syst)]x10(-4). The measured CP-odd fraction of the final state is 0.22+/-0.18(stat)+/-0.03(syst).     

Observation of the radiative decay D0-->phigamma

We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4).     

Evidence for CP violation in B0-->J/psipi0 decays

We present measurements of the branching fraction and time-dependent CP asymmetries in B0-->J/psipi0 decays based on 466 x 10(6) Upsilon(4S)-->BB over events collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We measure the CP asymmetry parameters S= -1.23+/-0.21(stat)+/-0.04(syst) and C= -0.20+/-0.19(stat)+/-0.03(syst), where the measured value of (S, C) is 4.0 standard deviations from (0, 0) including systematic uncertainties. The branching fraction is determined to be B(B0-->J/psipi0)=[1.69+/-0.14(stat)+/-0.07(syst)]x10(-5).     

Study of the decay B0(B- 0)-->rho+rho-, and constraints on the Cabibbo-Kobayashi-Maskawa angle alpha

Using a data sample of 89 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC, we measure the B0(B (0))-->rho(+)rho(-) branching fraction as [30+/-4(stat)+/-5(syst)]x10(-6) and a longitudinal polarization fraction of f(L)=0.99+/-0.03(stat)+0.04-0.03(syst). We measure the time-dependent-asymmetry parameters of the longitudinally polarized component of this decay as C(L)=-0.17+/-0.27(stat)+/-0.14(syst) and S(L)=-0.42+/-0.42(stat)+/-0.14(syst). We exclude values of alpha between 19 degrees and 71 degrees (90% C.L.).     

Study of the rare decays B0-->D((*)+)(s)pi(-) and B0-->D((*)-)(s)K+

We report evidence for the decays B0-->D(+)(s)pi(-) and B0-->D(-)(s)K+ and the results of a search for B0-->D(*+)(s)pi(-) and B0-->D(*-)(s)K+ in a sample of 84 x 10(6) upsilon(4S) decays into BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) storage ring. We measure the branching fractions B(B0-->D(+)(s)pi(-))=[3.2+/-0.9(stat)+/-1.0(syst)] x 10(-5) and B(B0-->D(-)(s)K+)=[3.2+/-1.0(stat)+/-1.0(syst)] x 10(-5). We also set 90% C.L. limits B(B0-->D(*+)(s)pi(-))<4.1 x 10(-5) and B(B0-->D(*-)(s)K+)<2.5 x 10(-5).     

Measurement of the branching fractions and CP asymmetry of B--->D(0)((CP))K- decays with the BABAR detector

We present a study of B--->D(0)(CP)K- decays, where D(0)(CP) is reconstructed in CP-even channels, based on a sample of 88.8 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II e(+)e(-) storage ring. We measure the ratio of Cabibbo-suppressed to Cabibbo-favored branching fractions B(B--->D(0)(CP)K-)/B(B--->D(0)(CP)pi(-))=[8.8+/-1.6(stat)+/-0.5(syst)]x10(-2) and the CP asymmetry A(CP)=0.07+/-0.17(stat)+/-0.06(syst). We also measure B(B--->D0K-)/B(B--->D0pi(-))=[8.31+/-0.35(stat)+/-0.20(syst)]x10(-2) using a sample of 61.0 x 10(6) BB pairs.     

Evidence for the decay sigma+ --> pmu+ mu-

We report the first evidence for the decay Sigma(+)-->pmu(+)mu(-) from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is B(Sigma(+)-->pmu(+)mu(-))=[8.6(+6.6)(-5.4)(stat)+/-5.5(syst)]x10(-8). The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, Sigma(+)-->pP(0),P0-->mu(+)mu(-) with a P0 mass of 214.3+/-0.5 MeV/c(2) and branching ratio B(Sigma(+)-->pP(0),P0-->mu(+)mu(-))=[3.1(+2.4)(-1.9)(stat)+/-1.5(syst)]x10(-8).     

Measurement of D0-->pilnu(Klnu) form factors and absolute branching fractions

Using a 282 fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider, we study D0 decays to K-l+nu and pi-l+nu final states. The D0 flavor and momentum are tagged through a full reconstruction of the recoiling charm meson and additional mesons from fragmentation. The reconstruction method provides very good resolution in neutrino momentum and in q2=(pl+pnu)2. Normalizing to the total number of D0 tags, we measure the absolute branching fractions to be B(D0-->Klnu)=(3.45+/-0.07stat+/-0.20syst)% and B(D0-->pilnu)=(0.255+/-0.019stat+/-0.016syst)% and the semileptonic form factors (within the modified pole model) f+K(0)=0.695+/-0.007stat+/-0.022syst and f+pi(0)=0.624+/-0.020stat+/-0.030syst.     

Measurement of the branching fractions of exclusive _B-->D(*)(pi)l-_nu l decays in events with a fully reconstructed B meson

We report a measurement of the branching fractions for _B-->D(*)(pi)l- _nu(l) decays based on 341.1 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II e+ e- storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We obtain B(B- -->D(0)l-_nu(l)=(2.33+/-0.09(stat)+/-0.09(syst)%, B(B- -->D(*0)l-_nu(l)=(5.83+/-0.15(stat) +/-0.30(syst) %, B(_B(0)-->D+l-_nu(l)=(2.21+/-0.11(stat) +/-0.12(syst)%, B(_B(0)-->D(*)l-_nu(l)=(5.49+/-0.16(stat)+/-0.25(syst)%, B(B- -->D+pi-l-_nu(l)=(0.42+/-0.06(stat)+/-0.03(syst)%, B(B- -->D(*)+pi-l-_nu(l)=(0.59+/-0.05(stat)+/-0.04(syst)%, B(_B(0)-->D(0)pi+l-_nu(l)=(0.43+/-0.08(stat)+/-0.03(syst)%, and B(_B(0)-->D(*0)pi+l-_nu(l)=(0.48+/-0.08(stat)+/-0.04(syst)%.     

Observation of B-/+-->rho-/+rho0 decays

We report the first observation of the charmless vector-vector decay process B-/+-->rho(-/+)rho(0). The measurement uses a 78 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric e(+)e(-) collider operating at the Upsilon(4S) resonance. We obtain a branching fraction of B(B-/+-->rho(-/+)rho(0))=[31.7+/-7.1(stat)+3.8-6.7(syst)]x10(-6). An analysis of the rho helicity-angle distributions gives a longitudinal polarization fraction of Gamma(L)/Gamma=0.95+/-0.11(stat)+/-0.02(syst). We also measure the direct-CP-violating asymmetry A(CP)(B-/+-->rho(-/+)rho(0))=0.00+/-0.22(stat)+/-0.03(syst).     

Measurement of the branching fraction and photon energy moments of B-->Xs gamma and A(CP)(B --> X(s+d gamma))

The photon spectrum in B-->Xs gamma decay, where Xs is any strange hadronic state, is studied using a data sample of 88.5 x 10(6) e+ e- --> Upsilon(4S) --> BB decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, DeltaB(B --> Xs gamma) = (3.67+/-0.29(stat)+/-0.34(syst)+/-0.29(model)) x 10(-4), the first moment = 2.288+/-0.025+/-0.017+/-0.015 GeV, and the second moment E2(gamma) = 0.0328+/-0.0040+/-0.0023+/-0.0036 GeV2 are measured for the photon energy range 1.9 GeV < E gamma < 2.7 GeV. They are also measured for narrower E gamma ranges. The moments are then fit to recent theoretical calculations to extract the heavy quark expansion parameters m(b) and mu2(pi) and to extrapolate the partial branching fraction to E gamma > 1.6 GeV. In addition, the direct CP asymmetry A(CP)(B-->X(s+d gamma) is measured to be -0.110+/-0.115(stat)+/-0.017(syst).