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Design and Initial Tests of the Tracker-Converter ofthe Gamma-ray Large Area Space Telescope

Description: The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. It is the largest silicon-strip detector system ever built for launch into space, and its aggressive design emphasizes very low power consumption, passive cooling, low noise, high efficiency, minimal dead area, and a structure that is highly transparent to charged particles. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements. It is now installed in the completed LAT, which is being prepared for launch in early 2008.
Date: April 16, 2007
Creator: Atwood, W.B.; Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F. et al.
Partner: UNT Libraries Government Documents Department

A Measurement of the Semileptonic Branching Fraction of the B_s Meson

Description: We report a measurement of the inclusive semileptonic branching fraction of the B{sub s} meson using data collected with the BABAR detector in the center-of-mass energy region above the {gamma}(4S) resonance. We use the inclusive yield of {phi} mesons and the {phi} yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B{sub s} mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B{sub s} meson is determined to be {Beta}(B{sub s} {yields} {ell}{nu}X) = 9.5{sub -2.0}{sup +2.5}(stat){sub -1.9}{sup +1.1}(syst)%, where {ell} indicates the average of e and {mu}.
Date: June 12, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Rare Decay B+ \to K+pi0pi0 and Measurement of the Quasi-two Body Contributions B+ \to K*(892)+pi0, B+ \to f0(980)K+ and B+ \to chic0K+

Description: We report an analysis of charmless hadronic decays of charged B mesons to the final state K{sup +}{pi}{sup 0}{pi}{sup 0}, using a data sample of (470.9 {+-} 2.8) x 10{sup 6} B{bar B} events collected with the BABAR detector at the {Gamma}(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be {Beta}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = (16.2 {+-} 1.2 {+-} 1.5) x 10{sup -6} and A{sub CP}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = -0.06 {+-} 0.06 {+-} 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0}, B{sup +} {yields} f{sub 0}(980)K{sup +}, and B{sup +} {yields} {chi}{sub c0}K{sup +} quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0} and B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0} channels.
Date: December 13, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

A Study of Radiative Bottomonium Transitions using Converted Photons

Description: The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.
Date: August 15, 2011
Creator: Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J. et al.
Partner: UNT Libraries Government Documents Department

Search for Bbar to Lambda_c+ X l- nu Decays in Events with a Fully Reconstructed B Meson

Description: We present a search for semileptonic B decays to the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B{sup 0} mixing. We obtain a 90% confidence level upper limit of {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -} {bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X) < 3.5%.
Date: April 19, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Search for b --> u Transitions in B^{+-} --> [K^{-+} pi^{+-} pi0]_D K^{+-} Decays

Description: The authors present a study of the decays B{sup {+-}} {yields} DK{sup {+-}} with D mesons reconstructed in the K{sup +}{pi}{sup -}{pi}{sup 0} or K{sup -}{pi}{sup +}{pi}{sup 0} final states, where D indicates a D{sup 0} or a {bar D}{sup 0} meson. Using a sample of 474 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC, they measure the ratios R{sup {+-}} {triple_bond} {Lambda}(B{sup {+-}}{yields}[K{sup {-+}}{pi}{sup {+-}}{pi}{sup 0}]{sub D}K{sup {+-}})/{Lambda}(B{sup {+-}}{yields}[K{sup {+-}}{pi}{sup {-+}}{pi}{sup 0}]{sub D}K{sup {+-}}). They obtain R{sup +} = (5{sub -10}{sup +12}(stat){sub -4}{sup +2}(syst)) x 10{sup -3} and R{sup -} = (12{sub -10}{sup +12}(stat){sub -5}{sup +3}(syst)) x 10{sup -3}, from which they extract the upper limits at 90% probability: R{sup +} < 23 x 10{sup -3} and R{sup -} < 29 x 10{sup -3}. Using these measurements, they obtain an upper limit for the ratio r{sub B} of the magnitudes of the b {yields} u and b {yields} c amplitudes r{sub B} < 0.13 at 90% probability.
Date: August 12, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Search for CP Violation in the Decay tau- \to pi- K^0_S (>= 0 pi0) nu_tau

Description: We report a search for CP violation in the decay {tau}{sup -} {yields} {pi}{sup -}K{sub S}{sup 0}({>=} 0{pi}{sup 0}){nu}{sub {tau}} using a dataset of 437 million {tau} lepton pairs, corresponding to an integrated luminosity of 476 fb{sup -1}, collected with the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.45 {+-} 0.24 {+-} 0.11)%, approximately three standard deviations from the Standard Model prediction of (0.33 {+-} 0.01)%.
Date: February 16, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Search for CP Violation using T-odd Correlations in D+ to K+K0spi+pi- and DS+ to K+K0spi+pi- Decays

Description: We search for CP violation in a sample of 20,000 Cabibbo-suppressed decays, D{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}, and 30,000 Cabibbo-favored decays, D{sub s}{sup +} {yields} K{sup +}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -}. We use 520 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energies near 10.6 GeV. We search for CP violation in the difference between the T-odd asymmetries obtained using triple product correlations of the D+ (D{sub s}{sup +}) and D{sup -} (D{sub s}{sup -}) decays, respectively. The T violation parameter values obtained are {Alpha}{sub T} (D{sup +}) = (-12.0 {+-} 10.0{sub stat} {+-} 4.6{sub syst}) x 10{sup -3} and {Alpha}{sub T}(D{sub s}{sup +}) = (-13.6 {+-} 7.7{sub stat} {+-} 3.4{sub syst}) x 10{sup -3}, which are consistent with the Standard Model expectations.
Date: August 22, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Measurements of Branching Fractions and CP Asymmetries and Studies of Angular Distributions for B to phi phi K Decays

Description: We present branching fraction and CP asymmetry measurements as well as angular studies of B {yields} {phi}{phi}K decays using 464 x 10{sup 6} B{bar B} events collected by the BABAR experiment. The branching fractions are measured in the {phi}{phi} invariant mass range below the {eta}{sub c} resonance (m{sub {phi}{phi}} < 2.85 GeV). We find {Beta}(B{sup +} {yields} {phi}{phi}K{sup +}) = (5.6 {+-} 0.5 {+-} 0.3) x 10{sup -6} and {Beta}(B{sup 0} {yields} {phi}{phi}K{sup 0}) = (4.5 {+-} 0.8 {+-} 0.3) x 10{sup -6}, where the first uncertaintiy is statistical and the second systematic. The measured direct CP asymmetries for the B{sup {+-}} decays are A{sub CP} = -0.10 {+-} 0.08 {+-} 0.02 below the {eta}{sub c} threshold (m{sub {phi}{phi}} < 2.85 GeV) and A{sub CP} = 0.09 {+-} 0.10 {+-} 0.02 in the {eta}{sub c} resonance region (m{sub {phi}{phi}} in [2.94,3.02] GeV). Angular distributions are consistent with J{sub P} = 0{sup -} in the {eta}{sub c} resonance region and favor J{sup P} = 0{sup +} below the {eta}{sub c} resonance.
Date: August 15, 2011
Creator: Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J. et al.
Partner: UNT Libraries Government Documents Department

Measurements of branching fractions, polarizations, and direct CP-violation asymmetries in B -> rho0 K* and B -> f0(980) K* decays

Description: We present measurements of the branching fractions, longitudinal polarization, and direct CP-violation asymmetries for the decays B{sup +} {yields} {rho}{sup 0}K*{sup +} and B{sup +} f{sub 0}(980)K*{sup +} with a sample of (467 {+-} 5) x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. We observe B{sup +} {yields} {rho}{sup 0}K*{sup +} with a significance of 5.3{sigma} and measure the branching fraction {Beta}(B{sup +} {yields} {rho}{sup 0}K*{sup +}) = (4.6 {+-} 1.0 {+-} 0.4) x 10{sup -6}, the longitudinal polarization f{sub L} = 0.78 {+-} 0.12 {+-} 0.03, and the CP-violation asymmetry A{sub CP} = 0.31 {+-} 0.13 {+-} 0.03. We observe B{sup +} {yields} f{sub 0}(980)K*{sup +} and measure the branching fraction {Beta}(B{sup +} {yields} f{sub 0}(980)K*{sup +}) x {Beta}(f{sub 0}(980) {yields} {pi}{sup +}{pi}{sup -}) = (4.2 {+-} 0.6 {+-} 0.3) x 10{sup -6} and the CP-violation asymmetry A{sub CP} = -0.15 {+-} 0.12 {+-} 0.03. The first uncertainty quoted is statistical and the second is systematic.
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Study of di-pion Bottomonium Transitions and Search for the h_b(1P) State

Description: We study inclusive di-pion decays using a sample of 108 x 10{sup 6} {Upsilon}(3S) events recorded with the BABAR detector. We search for the decay mode {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b} (1P) and find no evidence for the bottomonium spin-singlet state h{sub b}(1P) in the invariant mass distribution recoiling against the {pi}{sup +}{pi}{sup -} system. Assuming the h{sub b}(1P) mass to be 9.900 GeV/c{sup 2}, we measure the upper limit on the branching fraction {Beta}[{Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}h{sub b}(1P)] < 1.2 x 10{sup -4}, at 90% confidence level. We also investigate the {chi}{sub bJ}(2P) {yields} {pi}{sup +}{pi}{sup -} {chi}{sub bJ}(1P), {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S), and {Upsilon}(2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S) di-pion transitions and present an improved measurement of the branching fraction of the {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(2S) decay and of the {Upsilon}(3S) - {Upsilon}(2S) mass difference.
Date: December 9, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Study of Y(3S, 2S)-> eta Y(1S) and Y(3S, 2S) -> pi pi- Y(1S) Hadronic Transitions

Description: We study the {Upsilon}(3S, 2S) {yields} {eta}{Upsilon}(1S) and {Upsilon}(3S, 2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S) transitions with 122 x 10{sup 6} {Upsilon}(3S) and 100 x 10{sup 6} {Upsilon}(2S) mesons collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. We measure {Beta}[{Upsilon}(2S) {yields} {eta}{Upsilon}(1S)] = (2.39 {+-} 0.31(stat.) {+-} 0.14(syst.)) x 10{sup -4} and {Lambda}[{Upsilon}(2S) {yields} {eta}{Upsilon}(1S)]/{Lambda}[{Upsilon}(2S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S)] = (1.35 {+-} 0.17(stat.) {+-} 0.08(syst.)) x 10{sup -3}. We find no evidence for {Upsilon}(3S) {yields} {eta}{Upsilon}(1S) and obtain {Beta}[{Upsilon}(3S) {yields} {eta}{Upsilon}(1S)] < 1.0 x 10{sup -4} and {Lambda}[{Upsilon}(3S) {yields} {eta}{Upsilon}(1S)]/{Lambda}[{Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -}{Upsilon}(1S)] < 2.3 x 10{sup -3} as upper limits at the 90% confidence level. We also provide improved measurements of the {Upsilon}(2S)-{Upsilon}(1S) and {Upsilon}(3S)-{Upsilon}(1S) mass differences, 562.170 {+-} 0.007(stat.) {+-} 0.088(syst.)MeV/c{sup 2} and 893.813 {+-} 0.015(stat.) {+-} 0.107(syst.)MeV/c{sup 2}, respectively.
Date: March 27, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Baryonic B decay B0bar to Lambda_c^+ anti-Lambda K-

Description: The authors report the observation of the baryonic B decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} with a significance larger than 7 standard deviations based on 471 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. They measure the branching fraction for the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +} {bar {Lambda}}K{sup -} to be (3.8 {+-} 0.8{sub stat} {+-} 0.2{sub sys} {+-} 1.0 {sub {Lambda}{sub c}{sup +}}) x 10{sup -5}. The uncertainties are statistical, systematic, and due to the uncertainty in the {Lambda}{sub c}{sup +} branching fraction. They find that the {Lambda}{sub c}{sup +} K{sup -} invariant mass distribution shows an enhancement above 3.5 GeV/c{sup 2}.
Date: November 8, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Measurement of Partial Branching Fractions of Inclusive Charmless B Meson Decays to K , K0, and pi

Description: The authors present measurements of partial branching fractions of B {yields} K{sup +}X, B {yields} K{sup 0} X, and B {yields} {pi}{sup +}X, where X denotes any accessible final state above the endpoint for B decays to charmed mesons, specifically for momenta of the candidate hadron greater than 2.34 (2.36) GeV for kaons (pions) in the B rest frame. These measurements are sensitive to potential new-phisics particles which could enter the b {yields} s(d) loop transitions. The analysis is performed on a data sample consisting of 383 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric energy collider. The results are in agreement with standard model predictions and exclude large enhancements of the inclusive branching fraction due to sources of new physics.
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Search for CP Violation in the Decay D+/- to Ks pi+/-

Description: We report on a search for CP violation in the decay D{sup {+-}} {yields} K{sub S}{sup 0}{pi}{sup {+-}} using a data set corresponding to an integrated luminosity of 469 fb{sup -1} collected with the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} storage rings. The CP-violating decay rate asymmetry A{sub CP} is determined to be (-0.44 {+-} 0.13(stat) {+-} 0.10(syst))%, consistent with zero at 2.7 {sigma} and with the standard model prediction of (-0.332 {+-} 0.006)%. This is currently the most precise measurement of this parameter.
Date: August 22, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP et al.
Partner: UNT Libraries Government Documents Department

Searches for the baryon- and lepton-number violating decays $B^0\rightarrow\Lambda_c^ \ell^-$, $B^-\rightarrow\Lambda\ell^-$, and $B^-\rightarrow\bar{\Lambda}\ell^-$

Description: Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either {Lambda}{sub c} or {Lambda} and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2 - 520) x 10{sup -8} are set on the branching fractions at the 90% confidence level.
Date: June 22, 2011
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 CP observables in B__ ->D_CPK__ decays and constraints on the CKM angle gamma

Description: Using the entire sample of 467 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we perform a 'GLW' analysis of B{sup {+-}} {yields} D{sup {+-}} decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A{sub CP+} = 0.25 {+-} 0.06 {+-} 0.02 and A{sub CP-} = -0.09 {+-} 0.07 {+-} 0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A{sub CP+} is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, R{sub CP+} = 1.18 {+-} 0.09 {+-} 0.05 and R{sub CP-} = 1.07 {+-} 0.08 {+-} 0.04. We infer frequentist confidence intervals for the angle {gamma} of the (db) unitarity triangle, for the strong phase difference {delta}{sub B}, and for the amplitude ratio r{sub B}, which are related to the B{sup -} {yields} D{sup -} decay amplitude by r{sub B}e{sup i({delta}{sub b-{gamma}})} = A(B{sup -} {yields} {bar D}{sup 0}K{sup -})/A(B{sup -} {yields} D{sup 0}K{sup 0-}). Including statistical and systematic uncertainties, they obtain 0.24 < r{sub B} < 0.45 (0.06 < r{sub B} < 0.51) and, modulo 180{sup o}, 11.3{sup o} < {gamma} < 22.7{sup o} or 80.9{sup o} < {gamma} < 99.1{sup o} or 157.3{sup o} < {gamma} 168.7{sup o} (7.0{sup o} < {gamma} < 173.0{sup o}) at the 68% (95%) confidence level.
Date: August 25, 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

SuperB Progress Report: Detector

Description: This report describes the present status of the detector design for SuperB. It is one of four separate progress reports that, taken collectively, describe progress made on the SuperB Project since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008.
Date: February 14, 2012
Creator: Grauges, E.; /Barcelona U., ECM; Donvito, G.; Spinoso, V.; /INFN, Bari /Bari U.; Manghisoni, M. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Decay B- --> Ds(*) K- l- nubar

Description: We report the observation of the decay B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{ell}{sup -}{bar {nu}}{sub {ell}} based on 342 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings at SLAC. A simultaneous fit to three D{sub s}{sup +} decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{ell}{sup -}{bar {nu}}{sub {ell}} with a significance greater than five standard deviations (including systematic uncertainties) and measure its branching fraction to be {Beta}(B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{ell}{sup -}{bar {nu}}{sub {ell}}) = [6.13{sub -1.03}{sup +1.04}(stat.) {+-} 0.43(syst.) {+-} 0.51({Beta}(D{sub s}))] x 10{sup -4}, where the last error reflects the limited knowledge of the D{sub s} branching fractions.
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP 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

Dalitz-plot Analysis of B0 -> anti-D0 pi pi-

Description: The authors report preliminary results from a study of the decay B{sup 0} {yields} {bar D}{sup 0}{pi}{sup +}{pi}{sup -} using a data sample of 470.9 {+-} 2.8 million B{bar B} events collected with the BABAR detector at the {Upsilon}(4S) resonance. Using the Dalitz-plot analysis technique, they find contributions from the intermediate resonances D*{sub 2}(2460){sup -}, D*{sub 0}(2400){sup -}, {rho}(770){sup 0} and f{sub 2}(1270) as well as a {pi}{sup +}{pi}{sup -} S-wave term, a {bar D}{sup 0}{pi}{sup -} nonresonant S-wave term and a virtual D*(2010) amplitude. They measure the branching fractions of the contributing decays.
Date: August 25, 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

Searches for Lepton Flavor Violation in the Decays tau+- ---> e+- gamma and tau+- ---> mu+- gamma

Description: Searches for lepton-flavor-violating decays of a {tau} lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 {+-} 7) x 10{sup 6} {tau} decays collected by the BABAR detector near the {Upsilon}(4S), {Upsilon}(3S) and {Upsilon}(2S) resonances. The searches yield no evidence of signals and they set upper limits on the branching fractions of {Beta}({tau}{sup {+-}} {yields} e{sup {+-}}{gamma}) < 3.3 x 10{sup -8} and {Beta}({tau}{sup {+-}} {yields} {mu}{sup {+-}}{gamma}) < 4.4 x 10{sup -8} at 90% confidence level.
Date: June 11, 2010
Creator: Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department