Limits on the decay-rate difference of neutral B mesons and on CP, T, and CPT violation in B(0-0)B oscillations.

Using events in which one of two neutral B mesons from the decay of an Upsilon(4S) meson is fully reconstructed, we determine parameters governing decay (DeltaGamma(d)/Gamma(d)), CP, and T violation (|q/p|), and CP and CPT violation (Re z,Im z). The results, obtained from an analysis of 88 x 10(6) Upsilon(4S) decays recorded by BABAR, are sgn(Re lambda(CP))DeltaGamma(d)/Gamma(d)=-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],(Re lambda(CP)/|lambda(CP)|) Re z=0.014+/-0.035(stat)+/-0.034(syst)[-0.072,0.101],Im z=0.038+/-0.029(stat)+/-0.025(syst)[-0.028,0.104]. The values inside the square brackets indicate the 90% confidence-level intervals. These results are consistent with standard model expectations.

Search for the radiative decays B-->rhogamma and B0-->omegagamma.

A search of the exclusive radiative decays B-->rho(770)gamma and B0-->omega(782)gamma is performed on a sample of about 84x10(6) BBmacr; events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- storage ring. No significant signal is seen in any of the channels. We set upper limits on the branching fractions B of B(B0-->rho(0)gamma)<1.2 x 10(-6), B(B+-->rho+gamma)<2.1 x 10(-6), and B(B0-->omegagamma)<1.0 x 10(-6) at 90% confidence level (C.L.). Using the assumption that Gamma(B-->rhogamma)=Gamma(B+-->rho(+)gamma)=2 x Gamma(B0-->rho(0)gamma), we find the combined limit B(B-->rhogamma)<1.9 x 10(-6), corresponding to B(B-->rhogamma)/B(B-->K*gamma)<0.047 at 90% C.L.

Measurement of the branching fraction and polarization for the decay B--->D*0K*-.

We present a study of the decay B--->D(*0)K(*-) based on a sample of 86 x 10(6) Upsilon(4S)-->BBmacr; decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure the branching fraction B(B--->D(*0)K(*-))=(8.3+/-1.1(stat)+/-1.0(syst)) x 10(-4), and the fraction of longitudinal polarization in this decay to be Gamma(L)/Gamma=0.86+/-0.06(stat)+/-0.03(syst).

Measurements of the mass and width of the eta(c) meson and of an eta(c)(2S) candidate.

The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state.

Measurement of the inclusive charmless semileptonic branching ratio of B mesons and determination of |V ub|.

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;)=[2.24+/-0.27(stat)+/-0.26(syst)+/-0.39(theo)]x10(-3) and derive the Cabibbo-Kobayashi-Maskawa matrix element |V(ub)|=[4.62+/-0.28(stat)+/-0.27(syst)+/-0.48(theo)]x10(-3).

Observation of a significant excess of pi0pi0 events in B meson decays.

We present a study of the decay B0-->pi(0)pi(0) based on a sample of 124 x 10(6) BB pairs recorded by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We observe 46+/-13+/-3 events, where the first error is statistical and the second is systematic, corresponding to a significance of 4.2 standard deviations including systematic uncertainties. We measure the branching fraction B(B0-->pi(0)pi(0))=(2.1+/-0.6+/-0.3)x10(-6), averaged over B0 and B(0) decays.

Evidence for the rare decay B-->K*l+l- and measurement of the B-->Kl+l- branching fraction.

We present evidence for the flavor-changing neutral current decay B-->K*l+l- and a measurement of the branching fraction for the related process B-->K l+l-, where l+l- is either an epsilon+epsilon- or a mu+mu- pair. These decays are highly suppressed in the standard model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123 x 10(6) Upsilon(4S)-->B(-)B decays collected with the BABAR detector at the SLAC PEP-II epsilon+epsilon- storage ring. Averaging over K(*) isospin and lepton flavor, we obtain the branching fractions B(B-->Kl+l-)=(0.65(+0.14)(-0.13)+/-0.04)x10(-6) and B(B-->K*l+l-)=(0.88(+0.33)(-0.29)+/-0.10)x10(-6), where the uncertainties are statistical and systematic, respectively. The significance of the B-->Kl+l- signal is over 8sigma, while for B-->K*l+l- it is 3.3sigma.

Measurements of branching fractions and CP-violating asymmetries in B0-->rho(+/-)h(-/+) decays.

We present measurements of branching fractions and CP-violating asymmetries in B0-->rho(+/-)pi(-/+) and B0-->rho-K+ decays. The results are obtained from a data sample of 88.9 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a time-dependent maximum likelihood fit we measure the branching fractions B(B0-->rho(+/-)pi(-/+))=[22.6+/-1.8 (stat)+/-2.2 (syst)]x10(-6) and B(B0-->rho-K+)=(7.3 -1.2( +1.3)+/-1.3)x10(-6), and the CP-violating charge asymmetries A(rhopi)(CP)=-0.18+/-0.08+/-0.03 and A(rhoK)(CP)=0.28+/-0.17+/-0.08, the direct CP violation parameter C(rhopi)=0.36+/-0.18+/-0.04 and the mixing-induced CP violation parameter S(rhopi)=0.19+/-0.24+/-0.03, and the dilution parameters DeltaC(rhopi)=0.28 -0.19( +0.18)+/-0.04 and DeltaS(rhopi)=0.15+/-0.25+/-0.03.

Rates, polarizations, and asymmetries in charmless vector-vector B meson decays.

With a sample of approximately 89 x 10(6) B(-)B pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B+-->phiK(*+), B0-->phiK(*0), B+-->rho(0)K(*+), and B+-->rho(0)rho(+). We also set an upper limit on the branching fraction for the decay B0-->rho(0)rho(0).

Search for D0-D(-)0 mixing and a measurement of the doubly Cabibbo-suppressed decay rate in D0-->Kpi decays.

We present results of a search for D0-D(-)0 mixing and a measurement of R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays, using D0-->K+pi- decays from 57.1 fb(-1) of data collected near sqrt[s]=10.6 GeV with the BABAR detector at the PEP-II collider. At the 95% confidence level, allowing for CP violation, we find the mixing parameters x('2)<0.0022 and -0.056

Measurements of CP-violating asymmetries and branching fractions in B meson decays to eta'K.

We present measurements of the branching fractions of the decays B+-->eta'K+ and B0-->eta'K0. For B0-->eta(')K(0)(S) we also measure the time-dependent CP-violation parameters S eta'(K(0)(S)) and C eta'(K(0)(S)), and for B+-->eta'K+ the time-integrated charge asymmetry A(ch). The data sample corresponds to 88.9 x 10(6) BB pairs produced by e(+)e(-) annihilation at the Upsilon(4S). The results are B(B+-->eta'K+)=(76.9+/-3.5+/-4.4) x 10(-6), B(B0-->eta'K0)=(60.6+/-5.6+/-4.6) x 10(-6), S eta'(K(0)(S))=0.02+/-0.34+/-0.03, C eta'(K(0)(S))=0.10+/-0.22+/-0.04, and A(ch)=0.037+/-0.045+/-0.011.

Measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B0-->D(*+)D(*-).

We present a measurement of time-dependent CP asymmetries and an updated determination of the CP-odd fraction in the decay B0-->D(*+)D(*-) using a data sample of 88x10(6)BB pairs collected by the BABAR detector at the PEP-II B Factory at SLAC. We determine the CP-odd fraction to be 0.063+/-0.055(stat)+/-0.009(syst). The time-dependent CP asymmetry parameters Im(lambda(+)) and /lambda(+)/ are determined to be 0.05+/-0.29(stat)+/-0.10(syst) and 0.75+/-0.19(stat)+/-0.02(syst), respectively. The standard model predicts these parameters to be -sin(2beta and 1, respectively, in the absence of penguin diagram contributions.

Limits on D0-macro D0 mixing and CP violation from the ratio of lifetimes for decay to K-pi+, K-K+, and pi- pi+.

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.)]%.

Rare B decays into states containing a J/psi meson and a meson with s(-)s quark content.

We report a study of the B meson decays, B+ --> J/psiphiK+, B0 --> J/psiphiK(0)(S), B0 --> J/psiphi, B0 --> J/psieta, and B0 --> J/psieta' using 56 x 10(6) B(-)B events collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II e(+)e(-) asymmetric-energy storage ring. We measure the branching fractions B(B+ --> J/psiphiK+)=(4.4+/-1.4(stat)+/-0.5(syst))x 10(-5) and B(B0 --> J/psiphiK(0)(S))=(5.1+/-1.9(stat)+/-0.5(syst))x 10(-5), and set upper limits at 90% confidence level for the branching fractions B(B0 --> J/psiphi)<9.2 x 10(-6), B(B0 --> J/psieta)<2.7 x 10(-5), and B(B0 --> J/psieta')<6.3 x 10(-5).

Study of time-dependent CP asymmetry in neutral B decays to J/psi pi0.

We present the first study of the time-dependent CP-violating asymmetry in B0-->J/psi pi(0) decays using e(+)e(-) annihilation data collected with the BABAR detector at the Upsilon(4S) resonance during the years 1999-2002 at the PEP-II asymmetric-energy B Factory at SLAC. Using approximately 88 x 10(6) BB; pairs, our results for the coefficients of the cosine and sine terms of the CP asymmetry are C(J/psi pi(0))=0.38+/-0.41(stat)+/-0.09(syst) and S(J/psi pi(0))=0.05+/-0.49(stat)+/-0.16(syst).

Observation of the decay B+/--->pi+/-pi0, study of B+/--->K+/-pi0, and search for B0-->pi0pi0.

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))=-0.03(+0.18)(-0.17)+/-0.02 and AK+/-(pi(0))=-0.09+/-0.09+/-0.01. We place a 90% confidence-level upper limit on the branching fraction B(B0-->pi(0)pi(0)) of 3.6 x 10(-6).

Measurements of the branching fractions and bounds on the charge asymmetries of charmless three-body charged B decays.

We present measurements of branching fractions and charge asymmetries for charmless B-meson decays to three-body final states of charged pions and kaons. The analysis uses 81.8 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II asymmetric B Factory. We measure the branching fractions B(B+-->pi(+)pi(-)pi(+))=(10.9+/-3.3+/-1.6)x10(-6), B(B+-->K+pi(-)pi(+))=(59.1+/-3.8+/-3.2)x10(-6), and B(B+-->K+K-K+)=(29.6+/-2.1+/-1.6)x10(-6) and provide 90% C.L. upper limits for other decays. We observe no charge asymmetries for these modes.

Observation of a narrow meson state decaying to D(+)(s)pi(0) at a mass of 2.32 GeV/c(2).

We have observed a narrow state near 2.32 GeV/c(2) in the inclusive D(+)(s)pi(0) invariant mass distribution from e(+)e(-) annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a J(P)=0(+) assignment. The data sample corresponds to an integrated luminosity of 91 fb(-1) recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring.

Evidence for B+-->J/psip(-)Lambda; and search for B0-->J/psip(-)p.

We have performed a search for the decays B+-->J/psip(-)Lambda; and search for B0-->J/psip(-)p. in a data set of (88.9+/-1.0) x 10(6) Upsilon(4S) decays collected by the BABAR experiment at the PEP-II e(+)e(-) storage ring at the Stanford Linear Accelerator Center. Four charged B candidates have been observed with an expected background of 0.21+/-0.14 events. The corresponding branching fraction is (12(+9)(-6)) x 10(-6), where statistical and systematic uncertainties have been combined. The result can be interpreted as a 90% confidence level (C.L.) upper limit of 26 x 10(-6). We also find one B0 candidate, with an expected background of 0.64+/-0.17 events, implying a 90% C.L. upper limit of 1.9 x 10(-6).

Measurement of the branching fraction, and bounds on the CP-violating asymmetries, of neutral B decays to D*+/- D-/+.

We present measurements of the branching fraction and CP-violating asymmetries for neutral B decays to D(*+/-)D-/+. The measurement uses a data sample of approximately 88x10(6) Upsilon(4S)-->BBmacr; decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)-e(-) collider. By fully reconstructing the D(*+/-)D-/+ decay products, we measure the branching fraction to be (8.8+/-1.0+/-1.3)x10(-4) and the time-integrated CP-violating asymmetry between the rates to D(*-)D+ and D(*+)D- to be A=-0.03+/-0.11+/-0.05. We also measure the time-dependent CP-violating asymmetry parameters to be S(-+)=-0.24+/-0.69+/-0.12, C(-+)=-0.22+/-0.37+/-0.10 for B-->D(*-)D+ and S(+-)=-0.82+/-0.75+/-0.14, C(+-)=-0.47+/-0.40+/-0.12 for B-->D(*+)D-. In each case, the first error is statistical and the second error is systematic.