Improved Measurement of CP Violation in Neutral BDecays to \ccbar s

The authors present updated measurements of time-dependent CP asymmetries in fully-reconstructed neutral B decays to several CP eigenstates containing a charmonium meson. The measurements use a data sample of (383 {+-} 4) x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II B factory. They determine sin2{beta} = 0.714 {+-} 0.032(stat) {+-} 0.018(syst) and |{lambda}| = 0.952 {+-} 0.022(stat) {+-} 0.017(syst)

Search for a Narrow Resonance in e e- to Four Lepton Final States

Motivated by recent models proposing a hidden sector with {approx} GeV scale force carriers, we present a search for a narrow dilepton resonance in 4 lepton final states using 536 fb{sup -1} collected by the BABAR detector. We search for the reaction, e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} (l{sup +}l{sup -})(l{prime}{sup +}l{prime}{sup -}), where the leptons carry the full 4-momentum and the two dilepton pair invariant masses are equal. We do not observe a significant signal and we set 90% upper limits of {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} e{sup +}e{sup -}e{sup +}e{sup -}) < (15-70) ab, {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} e{sup +}e{sup -}{mu}{sup +}{mu}{sup -} < (15-40) ab, and {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} {mu}{sup +}{mu}{sup -}{mu}{sup +}{mu}{sup -}) < 11-17) ab in the W{prime} mass range between 0.24 and 5.3GeV/c{sup 2}. Under the assumption that the W{prime} coupling to electrons and muons is the same, we obtain a combined upper limit of {sigma}e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} l{sup +}l{sup -}l{prime}{sup +}l{prime}{sup -} < (25-60) ab. Using these limits, we constrain the product of the SM-dark sector mixing and the dark coupling constant in the case of a non-Abelian Higgsed dark sector

Measurements of time-dependent CP asymmetries in B0 --> D(*)+D(*)- decays

We present new measurements of time-dependent CP asymmetries for B{sup 0} {yields} D{sup (*)+}d{sup (*)-} decays using (467 {+-} 5) x 10{sup 6} B{bar B} pairs collected with the BABAR detector located at the PEP-II B Factory at the Stanford Linear Accelerator Center. We determine the CP-odd fraction of the B{sup 0} {yields} D*{sup +}D*{sup -} decays to be R{perpendicular} = 0.158 {+-} 0.028 {+-} 0.006 and find CP asymmetry parameters for the CP-even component of the decay S{sub +} = -0.76 {+-} 0.16 {+-} 0.04 and C{sub +} = 0.00 {+-} 0.12 {+-} 0.02. We measure S = -0.63{+-}0.36{+-}0.05 and C = -0.07{+-}0.23{+-}0.03 for B{sup 0} {yields} D{sup +}D{sup -}, S = -0.62{+-}0.21{+-}0.03 and C = 0.08 {+-} 0.17 {+-} 0.04 for B{sup 0} {yields} D*{sup +}D{sup -}, and S = -0.73 {+-} 0.23 {+-} 0.05 and C = 0.00 {+-} 0.17 {+-} 0.03 for B{sup 0} {yields} D{sup +}D*{sup -}. For the B{sup 0} {yields} D*{sup {+-}}D{sup {-+}} decays, we also determine the CP-violating asymmetry A = 0.008 {+-} 0.048 {+-} 0.013. In each case, the first uncertainty is statistical and the second is systematic. The measured values for the asymmetries are all consistent with the Standard Model

Measurement of Branching Fractions of B0 Decays to K1(1270)+ pi- and K1(1400)+ pi-

We present a measurement of the branching fraction of neutral B meson decaying to final states containing a K1 meson, i.e. K{sub 1}(1270) and K{sub 1}(1400), and a charged pion. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 454 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. We measure the branching fraction {Beta}(B{sup 0} {yields} K{sub 1}{sup +}{pi}{sup -}) = (31.0 {+-} 2.7 {+-} 6.9) x 10{sup -6}, where the first error quoted is statistical and the second is systematic. In the framework of the K-matrix formalism used to describe these decays, we also set limits on the ratio of the production constants for the K{sub 1}(1270){sup +} and K{sub 1}(1400){sup +} mesons in B{sup 0} decays

Amplitude Analysis of the Decay B0->K+pi-pi0

We report an updated amplitude analysis of the charmless hadronic decays of neutral B mesons to K{sup +} {pi}{sup -}{pi}{sup 0}. With a sample of 454 million {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B{sup 0} and B{sup 0} decays and determine the corresponding CP-averaged fit fractions and charge asymmetries

Measurement of Ratios of Branching Fractions and CP-Violating Asymmetries of B+/- --> D*K +/- decays

The authors report a study of B{sup {+-}} {yields} D*K{sup {+-}} decays with D* decaying to D{pi}{sup 0} or D{gamma}, using 383 x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. The D meson decays under study include a non-CP mode (K{sup {+-}}{pi}{sup {-+}}), CP-even modes (K{sup {+-}}K{sup {-+}}, {pi}{sup {+-}}{pi}{sup {-+}}) and CP-odd modes (K{sub S}{sup 0}{pi}{sup 0}, K{sub S}{sup 0}{phi}, K{sub S}{sup 0}{omega}). They measure ratios (R*{sub CP{+-}}) of branching fractions of decays to CP eigenmode states and to flavor-specific states as well as CP asymmetries A*{sub CP{+-}} = -0.11 {+-} 0.09 {+-} 0.01, R*{sub CP+} = 1.31 {+-} 0.13 {+-} 0.04, and A*{sub CP-} = 0.06 {+-} 0.10 {+-} 0.02, R*{sub CP-} = 1.10 {+-} 0.12 {+-} 0.04, where the first error is statistical and the second error is systematic. Translating the results into an alternative parameterization, widely used for related measurements, they obtain x*{sub +} = 0.11 {+-} 0.06 {+-} 0.02 and x*{sub -} = 0.00 {+-} 0.06 {+-} 0.01. No significant CP-violating charge asymmetry is found in either the flavor-specific mode D {yields} K{sup {+-}}{pi}{sup {-+}} or in B{sup {+-}} {yields} D*{pi}{sup {+-}} decays