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Observation and Polarization of B->phiK1+ and phiK*2+

Description: With the full BABAR data sample of 465 million B{bar B} pairs, they observe the decays B{sup {+-}} {yields} {psi}K{sub 1}(1270){sup {+-}} and B{sup {+-}} {yields} {psi}K*{sub 2}(1430){sup {+-}}. They measure the branching fractions (6.1 {+-} 1.6 {+-} 1.1) x 10{sup -6} and (8.4 {+-} 1.9 {+-} 0.9) x 10{sup -6} and the fractions of longitudinal polarization 0.46{sub -0.13-0.07}{sup +0.12+0.03} and 0.80{sub -0.10}{sup +0.09} {+-} 0.03, respectively. They also report on the B{sup {+-}} {yields} {psi}K*{sub 0}(1430){sup {+-}} decay branching fraction of (7.0 {+-} 1.3 {+-} 0.9) x 10{sup -6} and several parameters sensitive to CP violation and interference in the above three decays. Upper limits are placed on the B{sup {+-}} decay rates to final states with {psi} and K{sub 1}(1400){sup {+-}}, K*(1410){sup {+-}}, K{sub 2}(1770){sup {+-}}, or K{sub 2}(1820){sup {+-}}. Understanding the observed polarization pattern requires amplitude contributions from an uncertain source.
Date: October 31, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

Measurement of Time-Dependent CP Asymmetry in B0 --> KS pi0 gamma Decays

Description: The authors measure the time-dependent CP asymmetry in B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} decays for two regions of K{sub S}{sup 0}-{pi}{sup 0} invariant mass, m(K{sub S}{sup 0}{pi}{sup 0}), using the final BABAR data set of 467 x 10{sup 6} B{bar B} pairs collected at the PEP-II e{sup +}e{sup -} collider at SLAC. They find 339 {+-} 24 B{sup 0} {yields} K*{sup 0}{gamma} candidates and measure S{sub K*{gamma}} = -0.03 {+-} 0.29 {+-} 0.03 and C{sub K*{gamma}} = -0.14 {+-} 0.16 {+-} 0.03. In the range 1.1 < m(K{sub S}{sup 0}{pi}{sup 0}) < 1.8 GeV/c{sup 2} they find 133 {+-} 20 B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} candidates and measure S{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = -0.78 {+-} 0.59 {+-} 0.09 and C{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = -0.36 {+-} 0.33 {+-} 0.04. The uncertainties are statistical and systematic, respectively.
Date: October 20, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Date: October 17, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

A Search for Invisible Decays of the Upsilon(1S)

Description: We search for invisible decays of the {Upsilon}(1S) meson using a sample of 91.4 x 10{sup 6} {Upsilon}(3S) mesons collected at the BABAR/PEP-II B Factory. We select events containing the decay {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -} {Upsilon}(1S) and search for evidence of an undetectable {Upsilon}(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction {Beta}({Upsilon}(1S) {yields} invisible) < 3.0 x 10{sup ?4} at the 90% confidence level.
Date: October 17, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurement of Branching Fractions of B decays to K1(1270)pi and K1(1400)pi and Determination of the CKM angle alpha from B0 --> a1(1260) /- pi-/

Description: We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K{sub 1}(1270) or K{sub 1}(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. We measure the branching fractions {Beta}(B{sup 0} {yields} K{sub 1}(1270){sup +}{pi}{sup -} + K{sub 1}(1400){sup +}{pi}{sup -}) = 3.1{sub 0.7}{sup +0.8} x 10{sup -5} and {Beta}(B{sup +} {yields} K{sub 1}(1270){sup 0}{pi}{sup +} + K{sub 1}(1400){sup 0}{pi}{sup +}) = 2.9{sub -1.7}{sup +2.9} x 10{sup -5} (< 8.2 x 10{sup -5} at 90% confidence level), where the errors are statistical and systematic combined. The B{sup 0} decay mode is observed with a significance of 7.5{sigma}, while a significance of 3.2{sigma} is obtained for the B{sup +} decay mode. Based on these results, we estimate the weak phase {alpha} = (79 {+-} 7 {+-} 11){sup o} from the time dependent CP asymmetries in B{sup 0} {yields} a{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decays.
Date: October 30, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurements of the tau Mass and Mass Difference of the tau^+ and tau^- at BABAR

Description: The authors present the result of a precision measurement of the mass of the {tau} lepton, M{sub {tau}}, based on 423 fb{sup -1} of data recorded at the {Upsilon}(4S) resonance with the BABAR detector. Using a pseudomass endpoint method, they determine the mass to be 1776.68 {+-} 0.12(stat) {+-} 0.41(syst) MeV. They also measure the mass difference between the {tau}{sup +} and {tau}{sup -}, and obtain (M{sub {tau}{sup +}} - M{sub {tau}{sup -}})/M{sub AVG}{sup {tau}} = (-3.4 {+-} 1.3(stat) {+-} 0.3(syst)) x 10{sup -4}, where M{sub AVG}{sup {tau}} is the average value of M{sub {tau}{sup +}} and M{sub {tau}{sup -}}.
Date: October 30, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi

Description: We present a study of ten B-meson decays to a D{sup (*)}, a proton-antiproton pair, and a system of up to two pions using BABAR's data set of 455 x 10{sup 6} B{bar B} pairs. Four of the modes {bar B}{sup 0} {yields} D{sup 0}p{bar p}, {bar B}{sup 0} {yields} D*{sup 0}p{bar p}, {bar B}{sup 0} {yields} D{sup +}p{bar p}{pi}{sup -}, {bar B}{sup 0} {yields} D{sup ast+}p{bar p}{pi}{sup -} are studied with improved statistics compared to previous measurements; six of the modes (B{sup -} {yields} D{sup 0}p{bar p}{pi}{sup -}, B{sup -} {yields} D*{sup 0}p{bar p}{pi}{sup -}, {bar B}{sup 0} {yields} D{sup 0}p{bar p}{pi}{sup -}{pi}{sup +}, {bar B}{sup 0} {yields} D*{sup 0}p{bar p}{pi}{sup -}{pi}{sup +}, B{sup -} {yields} D{sup +}p{bar p}{pi}{sup -}{pi}{sup -}, B{sup -} {yields} D{sup ast+}p{bar p}{pi}{sup -}{pi}{sup -}) are first observations. The branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays. Kinematic distributions for 3-body decays show non-overlapping threshold enhancements in m(p{bar p}) and m(D{sup (*)0}p) in the Dalitz plots. For 4-body decays, m(p{pi}{sup -}) mass projections show a narrow peak with mass and full width of (1497.4 {+-} 3.0 {+-} 0.9)MeV/c{sup 2} and (47 {+-} 12 {+-} 4)MeV/c{sup 2}, respectively, where the first (second) errors are statistical (systematic). For 5-body decays, mass projections are similar to phase space expectations. All results are preliminary.
Date: October 17, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Observation of the baryonic B-decay B0bar -> LambdaC antiproton K- pi

Description: The authors report the observation of the baryonic B-decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p}K{sup -}{pi}{sup +}, excluding contributions from the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar {Lambda}}K{sup -}. Using a data sample of 467 million B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, the measured branching fraction is (4.33 {+-} 0.82){sub stat} {+-} 0.33{sub syst} {+-} 1.13{sub {Lambda}{sub c}{sup +}} x 10{sup -5}. In addition they find evidence for the resonant decay {bar B}{sup 0} {yields} {Sigma}{sub c}(2455){sup ++}{bar p}K{sup -} and determine its branching fraction to be (1.11 {+-} 0.30{sub stat} {+-} 0.09{sub syst} {+-} 0.29{sub {Lambda}{sub c}{sup +}}) x 10{sup -5}. The errors are statistical, systematic, and due to the uncertainty in the {Lambda}{sub c}{sup +} branching fraction. For the resonant decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p}{bar K}*{sup 0} we obtain an upper limit of 2.42 x 10{sup -5} at 90% confidence level.
Date: October 20, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurement of D0-D0bar Mixing using the Ratio of D0->K-pi and K-K Lifetimes

Description: We measure the rate of D{sup 0}-{bar D}{sup 0} mixing with the observable y{sub CP} = ({tau}{sub K{pi}}/{tau}{sub KK}) - 1, where {tau}{sub KK} and {tau}{sub K{pi}} are respectively the mean lifetimes of CP-even D{sup 0} {yields} K{sup +}K{sup -} and CP-mixed D{sup 0} {yields} K{sup -}{pi}{sup +} decays, using a data sample of 384 fb{sup -1} collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D{sup 0} and {bar D}{sup 0} decays where the initial flavor of the decaying meson is not determined, we obtain y{sub CP} = [1.12 {+-} 0.26(stat) {+-} 0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3{sigma}, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y{sub CP} obtained from a sample of D*{sup +} {yields} D{sup 0}{pi}{sup +} events, where the D{sup 0} decays to K{sup -}{pi}{sup +}, K{sup +}K{sup -}, and {pi}{sup +}{pi}{sup -}, which is disjoint with the untagged D{sup 0} events used here. Combining the two results taking into account statistical and systematic uncertainties, where the systematic uncertainties are assumed to be 100% correlated, we find y{sub CP} = [1.16 {+-} 0.22(stat) {+-} 0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1{sigma}.
Date: October 17, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Evidence for an excess of B to D(*) Tau Nu decays

Description: Based on the full BABAR data sample, we report improved measurements of the ratios R(D{sup (*)}) = {Beta}({bar B} {yields} D{sup (*)} {tau}{sup -}{bar {nu}}{sub {tau}})/{Beta}({bar B} {yields} D{sup (*)} {ell}{sup -}{bar {nu}}{sub {ell}}), where {ell} is either e or {mu}. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 {+-} 0.058 {+-} 0.042 and R(D*) = 0.332 {+-} 0.024 {+-} 0.018, which exceed the Standard Model expectations by 2.0{sigma} and 2.7{sigma}, respectively. Taken together, our results disagree with these expectations at the 3.4{sigma} level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay {bar B} {yields} D{tau}{sup -} {bar {nu}}{sub {tau}}, with a significance of 6.8{sigma}.
Date: October 9, 2012
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

A Model-Independent Search for the decay B->l nu gamma

Description: The authors present a search for the radiative leptonic decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}, where {ell} = e, {mu}, using a data sample of 465 million B{bar B} pairs collected by the BABAR experiment. In this analysis, they fully reconstruct the hadronic decay of one of the B mesons in {Upsilon}(4S) {yields} B{sup +}B{sup -} decays, then search for evidence of B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma} in the rest of the event. They observe no significant evidence of signal decays and report model-independent branching fraction upper limits of {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}{gamma}) < 17 x 10{sup -6}, {Beta}(B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{gamma}) < 24 x 10{sup -6}, and {Beta}(B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}) < 15.6 x 10{sup -6} ({ell} = e or {mu}), all at the 90% confidence level.
Date: October 9, 2012
Creator: Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Exclusive Production of Ds Ds-, Ds* Ds-, and Ds* Ds*- via e e- Annihilation with Initial-State-Radiation

Description: The authors perform a study of exclusive production of D{sub s}{sup +}D{sub s}{sup -}, D*{sub s}{sup +}D{sub s}{sup -}, and D*{sub s}{sup +}D*{sub s}{sup -} final states in initial-state-radiation events from e{sup +}e{sup -} annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium 1{sup --} states. The data sample corresponds to an integrated luminosity of 525 fb{sup -1} and was recorded by the BABAR experiment at the PEP-II storage ring. The D{sub s}{sup +} D{sub s}{sup -}, D*{sub s}{sup +}D{sub s}{sup -}, and D*{sub s}{sup +}D*{sub s}{sup -} mass spectra show evidence of the known {psi} resonances. Limits are extracted for the branching ratios of the decays X(4260) {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-}.
Date: October 27, 2010
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Absolute Branching Fractions for $D^-_s\!\rightarrow\!\ell^-\bar{\nu}_{\ell}$ and Extraction of the Decay Constant $f_{D_s}$

Description: The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -}DKXD*{sub s}{sup -}, where D*{sub s}{sup -} {yields} D{sub s}{sup -}{gamma} and X represents additional pions from fragmentation. The D{sub s}{sup -} {yields} {ell}{sup 0}{nu}{sub {ell}} events are detected by full or partial reconstruction of the recoiling system DKX{gamma}{ell}. The branching fraction measurements are combined to determine the D{sub s}{sup -} decay constant f{sub D{sub s}} = (258.6 {+-} 6.4 {+-} 7.5) MeV, where the first uncertainty is statistical and the second is systematic.
Date: October 27, 2010
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department