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Dalitz Plot Analysis of D0 to Anti-K0 K+ K- And D/SJ States at BaBar

Description: A Dalitz plot analysis of D{sup 0} events reconstructed in the hadronic decay D{sup 0} {yields} {bar K}{sup 0}K{sup +}K{sup -} is presented here. The analysis is based on a data sample of 91.5 fb{sup -1}. Herewith enclosed is an updated, preliminary analysis of D{sub sJ} states using 125 fb{sup -1}. All data have been collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage rings at SLAC running at center-of-mass energies on and 40 MeV below the {Upsilon}(4S) resonance.
Date: October 15, 2007
Creator: Pappagallo, M.
Partner: UNT Libraries Government Documents Department

Measurement of the CKM Angle Gamma in B0 to Anti-D0 (D0) K*0 With a Dalitz Analysis of D0 to K(S) Pi+ Pi-

Description: The authors present a measurement of the angle {gamma} of the Unitarity Triangle with a Dalitz analysis of neutral D decays to K{sub S}{pi}{sup +}{pi}{sup -} from the processes B{sup 0} {yields} {bar D}{sup 0}(D{sup 0})K*{sup 0} ({bar B}{sup 0} {yields} D{sup 0}({bar D}{sup 0}){bar K}*{sup 0}) with K*{sup 0} {yields} K{sup +}{pi}{sup -} ({bar K}*{sup 0} {yields} K{sup -} {pi}{sup +}). Using a sample of 371 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at PEP II, they measure the angle {gamma} as a function of r{sub S}, the magnitude of the average ratio between b {yields} u and b {yields} c amplitudes. Combining this result with the available information on r{sub S}, they obtain {gamma} = (162 {+-} 56){sup o} or (342 {+-} 56){sup o} and r{sub S} < 0.55 at 95% probability.
Date: June 9, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Search for Hadronic Decays of a Light Higgs Boson in the Radiative Decay

Description: The authors search for hadronic decays of a light Higgs boson (A{sup 0}) produced in radiative decays of an {Upsilon}(2S) or {Upsilon}(3S) meson, {Upsilon} {yields} {gamma}A{sup 0}. The data have been recorded by the BABAR experiment at the {Upsilon}(3S) and {Upsilon}(2S) center of mass energies, and include (121.3 {+-} 1.2) x 10{sup 6} {Upsilon}(3S) and (98.3 {+-} 0.9) x 10{sup 6} {Upsilon}(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions {beta}({Upsilon}(nS) {yields} {gamma}A{sup 0}) {center_dot} {beta}(A{sup 0} {yields} hadrons) (n = 2 or 3) that range from 1 x 10{sup -6} for an A{sup 0} mass of 0.3 GeV/c{sup 2} to 8 x 10{sup -5} at 7 GeV/c{sup 2}.
Date: February 16, 2012
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
Partner: UNT Libraries Government Documents Department

Dalitz Plot Analysis of the Decay B0(B0bar) to K^+/- pi^-/+ pi0

Description: The authors report a Dalitz-plot analysis of the charmless hadronic decays of neutral B mesons to K{sup {+-}}{pi}{sup {-+}}{pi}{sup 0}. With a sample of (231.8 {+-} 2.6) x 10{sup 6}{Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, they measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B{sup 0} and {bar B}{sup 0} decays and determine the corresponding CP-averaged branching fractions and charge asymmetries. The inclusive branching fraction and CP-violating charge asymmetry are measured to be {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}) = (35.7{sub -1.5}{sup +2.6} {+-} 2.2) x 10{sup -6}, and {Alpha}{sub CP} = -0.030{sub -0.051}{sup +0.045} {+-} 0.055 where the first errors are statistical and the second systematic. They observe the decay B{sup 0} {yields} K*{sup 0}(892){pi}{sup 0} with the branching fraction {Beta}(B{sup 0} {yields} K*{sup 0}(892){pi}{sup 0}) = (3.6{sub -0.8}{sup +0.7} {+-} 0.4) x 10{sup -6}. This measurement differs from zero by 5.6 standard deviations (including the systematic uncertainties). The selected sample also contains B{sup 0} {yields} {bar D}{sup 0}{pi}{sup 0} decays where {bar D}{sup 0} {yields} K{sup +}{pi}{sup -}, and they measure {Beta}(B{sup 0} {yields} {bar D}{sup 0}{pi}{sup 0}) = (2.93 {+-} 0.17 {+-} 0.18) x 10{sup -4}.
Date: September 18, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Branching Fractions of the Rare Decays B0 to Ds(*)+pi-,B0 to Ds(*)+rho-, and B0 to Ds(*)-K(*)+

Description: The authors report the measurement of the branching fractions of the rare decays B{sup 0} {yields} D{sub s}{sup (*)+} {pi}{sup -}, B{sup 0} {yields} D{sub s}{sup (*)+} {rho}{sup -}, and B{sup 0} {yields} D{sub s}{sup (*)-} K{sup (*)+} in a sample of 381 x 10{sup 6} {Upsilon}(4S) decays into B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. They present evidence for the decay B{sup 0} {yields} D{sub s}{sup -} K*{sup +} and the vector-vector decays B{sup 0} {yields} D{sub s}{sup *+} {rho}{sup -} and B{sup 0} {yields} D{sub s}{sup *-} K{sup *+}, as well as the first measurement of the vector meson polarization in these decays. They also determine the ratios of the CM-suppressed to CKM-favored amplitudes r(D{sup (*)}{pi}) and r(D{sup (*)}{rho}) in decays B{sup 0} {yields} D{sup (*)}{sup {+-}}{pi}{sup {-+}} and B{sup 0} {yields} D{sup (*)}{sup {+-}}{rho}{sup {-+}}, and comment on the prospects for measuring the Cp observable sin(2{beta} + {gamma}).
Date: April 16, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

Study of B Meson Decays with Excited eta and eta-prime Mesons

Description: Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or {eta}{pi}{pi} final states with mass in the range (1.2-1.8) GeV/c{sup 2}. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B{sup +} {yields} {eta}(1475)K{sup +}, find evidence for the decay B{sup +} {yields} {eta}(1295)K{sup +}, and place upper limits on the decays B{sup +} {yields} {eta}(1405)K{sup +}, B{sup +} {yields} f{sub 1}(1285)K{sup +}, B{sup +} {yields} f{sub 1}(1420)K{sup +}, and B{sup +} {yields} {phi}(1680)K{sup +}.
Date: April 18, 2008
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Partner: UNT Libraries Government Documents Department

Performance and Aging Studies of BaBar Resistive Plate Chambers

Description: The BaBar detector is currently operating nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector in 2002. Although the average RPC efficiency remains high, numerous changes in the RPC performance (increased currents and rates) have been observed. A few of the highest rate RPCs have suffered efficiency losses of more than 15%. Several types of efficiency loss have been observed. Tests with humidified gas have shown that some of the lost efficiency is recoverable. However, efficiency losses in the highest rate regions have not yet improved with humid gases.
Date: October 13, 2006
Creator: Band, H. R.; Hollar, J.; Tan, P.; Anulli, F.; Baldini, R.; Calcaterra, A. et al.
Partner: UNT Libraries Government Documents Department

A Study of $e^+e^-\to p\bar{p}$ Using Initial StateRadiation with BaBar

Description: The e{sup +}e{sup -} {yields} p{bar p} cross-section is determined over a range of p{bar p} masses, from threshold to 4.5 GeV/c{sup 2}, by studying the e{sup +}e{sup -} {yields} p{bar p}{gamma} process. The data set corresponds to an integrated luminosity of 232 fb{sup -1}, collected with the BABAR detector at the PEP-II storage ring, at an e{sup +}e{sup -} center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for p{bar p} masses below 3 GeV/c{sup 2}; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c{sup 2}. We also measure J/{psi} {yields} p{bar p} and {psi}(2S) {yields} p{bar p} branching fractions and set an upper limit on Y(4260) {yields} p{bar p} production and decay.
Date: December 13, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Study of the $\tau^- to 3h^- 2h^+ \nu_\tau$ Decay

Description: The branching fraction of the {tau}{sup -} {yields} 3h{sup -} 2h{sup +} {nu}{sub {tau}} decay (h = {pi}, K) is measured with the BABAR detector to be (8.56 {+-} 0.05 {+-} 0.42) x 10{sup -4}, where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the {rho} resonance playing a strong role. The decay {tau}{sup -} {yields} f{sub 1}(1285){pi}{sup -}{nu}{sub {tau}}, with the f{sub 1}(1285) meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9 {+-} 0.7 {+-} 0.5) x 10{sup -4}.
Date: May 4, 2005
Creator: Aubert, Bernard; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Dalitz Plot Analysis of D0 to K0K+ K-

Description: A Dalitz plot analysis of approximately 12,500 D{sup 0} events reconstructed in the hadronic decay D{sup 0} {yields} {bar K}{sup 0} K{sup +}K{sup -} is presented. This analysis is based on a data sample of 91.5 fb{sup -1} collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings at SLAC running at center-of-mass energies on and 40 MeV below the {Upsilon}(4S) resonance. The events are selected from e{sup +}e{sup -} {yields} c{bar c} annihilations using the decay D*{sup +} {yields} D{sup 0}{pi}{sup +}. The following ratio of branching fractions has been obtained: BR = {Lambda}(D{sup 0} {yields} {bar K}{sup 0}K{sup +}K{sup -})/{Lambda}(D{sup 0} {yields} {bar K}{sup 0}{pi}{sup +}{pi}{sup -}) = (15.8 {+-} 0.1(stat.) {+-} 0.5 (syst.)) x 10{sup -2}. Estimates of fractions and phases for resonant and non-resonant contributions to the Dalitz plot are also presented. The a{sub 0}(980) {yields} {bar K}K projection has been extracted with little background. A search for Cp asymmetries on the Dalitz plot has been performed.
Date: July 12, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Study of B to pi ell nu and B to rho ell nu Decays and Determination of |V_ub|

Description: We present an analysis of exclusive charmless semileptonic B-meson decays based on 83 million B{bar B} pairs recorded with the BABAR detector at the {Upsilon}(4S) resonance. Using isospin symmetry, we measure branching fractions {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.38 {+-} 0.10 {+-} 0.16 {+-} 0.08) x 10{sup -4} and {Beta}(B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}) = (2.14 {+-} 0.21 {+-} 0.48 {+-} 0.28) x 10{sup -4}, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q{sup 2}, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V{sub ub}| = (3.82 {+-} 0.14 {+-} 0.22 {+-} 0.11{sub -0.52}{sup +0.88}) x 10{sup -3} from B {yields} {pi}{ell}{nu} where the fourth error reflects the uncertainty of the form-factor normalization.
Date: November 17, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

A Study of Production and Decay of Omega_c^0 Baryons in BABAR

Description: Production and decay of {Omega}{sub c}{sup 0} baryons is studied with {approx} 230 fb{sup -1} of data recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage ring at SLAC. The {Omega}{sub c}{sup 0} is reconstructed through its decays into {Omega}{sup -}{pi}{sup +}, {Omega}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}, {Xi}{sup -}K{sup -}{pi}{sup +}{pi}{sup +} final states. The invariant mass spectra are presented and the signal yields are extracted. Ratios of branching fractions are measured relative to the {Omega}{sub c}{sup 0} {yields} {Omega}{sup -}{pi}{sup +} mode {Beta}({Omega}{sub c}{sup 0} {yields} {Xi}{sup -} K{sup -}{pi}{sup +}{pi}{sup +})/{Beta}({Omega}{sub c}{sup 0} {yields} {Omega}{sup -}{pi}{sup +}) = 0.31 {+-} 0.15(stat.) {+-} 0.04(syst.), {Beta}({Omega}{sub c}{sup 0} {yields} {Omega}{sup -} {pi}{sup +}{pi}{sup -}{pi}{sup +})/{Beta}({Omega}{sub c}{sup 0} {yields} {Omega}{sup -}{pi}{sup +}) < 0.30 (90%CL). The momentum spectrum (not corrected for efficiency) of {Omega}{sub c}{sup 0} baryons is extracted from decays into {Omega}{sup -}{pi}{sup +}, establishing the first observation of {Omega}{sub c}{sup 0} production from B decays.
Date: September 28, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Study of J/psi pi+ pi- States Produced in B0 to J/psi pi+ pi- K^0 and B- to J/psi pi+ pi- K-

Description: We present results of a search for the X(3872) in B{sup 0} {yields} X(3872)K{sub S}{sup 0}, X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}, improved measurements of B{sup -} {yields} X(3872)K{sup -}, and a study of the J/{psi}{pi}{sup +}{pi}{sup -} mass region above the X(3872). We use 232 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage rings. The results include the 90% confidence interval 1.34 x 10{sup -6} < {Beta}(B{sup 0} {yields} X(3872)K{sup 0}, X {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 10.3 x 10{sup -6} and the branching fraction {Beta}(B{sup -} {yields} X(3872)K{sup -}, X {yields} J/{psi}{pi}{sup +}{pi}{sup -}) = (10.1 {+-} 2.5 {+-} 1.0) x 10{sup -6}. We observe a (2.7 {+-} 1.3 {+-} 0.2) MeV/c{sup 2} mass difference of the X(3872) produced in the two decay modes. Furthermore, we find an excess of J/{psi}{pi}{sup +}{pi}{sup -} events with an invariant mass just above 4.2 GeV/c{sup 2} that is consistent with recent observations in initial state radiation events.
Date: July 27, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

A Study of b to c and b to u Interference in the Decay B- to [K+ pi-]_D K*-

Description: Using a sample of 232 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II B-factory we study the decay B{sup -} {yields} [K{sup +}{pi}{sup -}]{sub D}K*{sup -} where the K{sup +}{pi}{sup -} is either from a Cabibbo-favored {bar D}{sup 0} decay or doubly-suppressed D{sup 0} decay. We measure two observables that are sensitive to the CKM angle {gamma}; the ratio R of the charge-averaged branching fractions for the suppressed and favored decays; and the charge asymmetry A of the suppressed decays: R = 0.046 {+-} 0.031(stat.) {+-} 0.008(syst.); A = -0.22 {+-} 0.61(stat.) {+-} 0.17(syst.).
Date: August 4, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the B+- --> rho+- pi0 Branching Fraction and Direct CP Asymmetry

Description: An improved measurement of the process B{sup {+-}} {yields} {rho}{sup {+-}}{pi}{sup 0} is presented. The data sample of 211 fb{sup -1} comprises 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The yield and CP asymmetry are calculated using an extended maximum likelihood fitting method. The branching fraction and asymmetry are found to be {Beta}(B{sup {+-}} {yields} {rho}{sup {+-}}{pi}{sup 0}) = [10.0 {+-} 1.4 (Stat.) {+-} 0.9 (Syst.)] x 10{sup -6} and {Alpha}{sub CP}(B{sup {+-}} {yields} {rho}{sup {+-}}{pi}{sup 0}) = -0.01 {+-} 0.13 (Stat.) {+-} 0.02 (Syst.), superseding previous measurements. The statistical significance of the signal is calculated to be 8.7{sigma}.
Date: June 29, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the $B^+\rightarrow p \bar{p} K^{+}$ Branching Fraction and Study of the Decay Dynamics

Description: With a sample of 232 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector, we study the decay B{sup +} {yields} p{bar p}K{sup +} excluding charmonium decays to p{bar p}. We measure a branching fraction {Beta}(B{sup +} {yields} p{bar p}K{sup +}) = (6.7 {+-} 0.5 {+-} 0.4) x 10{sup -6}. An enhancement at low p{bar p} mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate {Theta}*{sup ++} decaying into pK{sup +} in the mass range 1.43 to 2.00 GeV/c{sup 2} and set limits on {Beta}(B{sup +} {yields} {Theta}*{sup ++} {bar p}) x {Beta}({Theta}*{sup ++} {yields} pK{sup +}) at the 10{sup -7} level.
Date: July 6, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Observation of a Broad Structure in the $\pi^+\pi^-J/\psi$ Mass Spectrum around 4.26~GeV/$c^2$

Description: The authors study initial-state radiation events, e{sup +}e{sup -} {yields} {gamma}{sub ISR} {pi}{sup +}{pi}{sup -} J/{psi}, with data collected with the BABAR detector. They observe an accumulation of events near 4.26 GeV/c{sup 2} in the invariant-mass spectrum of {pi}{sup +}{pi}{sup -} J/{psi}. Fits of the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c{sup 2} is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/c{sup 2}, depending on the fit hypothesis.
Date: July 6, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Absolute Branching Fractions of$B^\pm \to K^\pm X_{c\bar c}$

Description: We study the two-body decays of B{sup {+-}} mesons to K{sup {+-}} and a charmonium state, X{sub c{bar c}}, in a sample of 210.5 fb{sup -1} of data from the BABAR experiment. We perform measurements of absolute branching fractions {Beta}(B{sup {+-}} {yields} K{sup {+-}} X{sub c{bar c}}) using a missing mass technique, and report several new or improved results. In particular, the upper limit {Beta}(B{sup {+-}} {yields} K{sup {+-}}(3872)) < 3.2 x 10{sup -4} at 90% CL and the inferred lower limit {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) > 4.2% will help in understanding the nature of the recently discovered X(3872).
Date: November 2, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Evidence for B+ to K0barK+ and B0 to K0K0bar, and Measurement of the Branching Fraction and Search for Direct CP Violation in B+ to K0pi+

Description: The authors present evidence for the b {yields} d penguin-dominated decays B{sup +} {yields} {bar K}{sup 0}K{sup +} and B{sup 0} {yields} K{sup 0}{bar K}{sup 0} with significances of 3.5 and 4.5 standard deviations, respectively. The results are based on a sample of 227 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure the branching fractions {Beta}(B{sup +} {yields} {bar K}{sup 0}K{sup +}) = (1.5 {+-} 0.5 {+-} 0.1) x 10{sup -6} (< 2.4 x 10{sup -6}) and {Beta}(B{sup 0} {yields} K{sup 0}{bar K}{sup 0}) = (1.19{sub -0.35}{sup +0.40} {+-} 0.13) x 10{sup -6}, where the uncertainties are statistical and systematic, respectively, and the upper limit on the branching fraction for {bar K}{sup 0}K{sup +} is at the 90% confidence level. They also present improved measurements of the charge-averaged branching fraction {Beta}(B{sup +} {yields} K{sup 0}{pi}{sup +}) = (26.0 {+-} 1.3 {+-} 1.0) x 10{sup -6} and CP-violating charge asymmetry {Alpha}{sub CP} (K{sup 0}{pi}{sup +}) = -0.09 {+-} 0.05 {+-} 0.01, where the uncertainties are statistical and systematic, respectively.
Date: July 12, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Improved Measurements of Branching Fractions for B0 -> pi+pi-, K+pi-, and Search for B0 -> K+K-

Description: We present preliminary measurements of branching fractions for the charmless two-body decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -} and K{sup +}{pi}{sup -}, and a search for B{sup 0} {yields} K{sup +}K{sup -} using a data sample of approximately 227 million B{bar B} decays. Signal yields are extracted with a multi-dimensional maximum likelihood fit, and the efficiency is corrected for the effects of final-state radiation. We find the charge-averaged branching fractions (in units of 10{sup -6}): {Beta}(B{sup 0} {yields} {pi}{sup +}{pi}{sup -}) = 5.5 {+-} 0.4 {+-} 0.3; {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}) = 19.2 {+-} 0.6 {+-} 0.6; and {Beta}(B{sup 0} {yields} K{sup +}K{sup -}) = < 0.40. The errors are statistical followed by systematic, and the upper limit on K{sup +}K{sup -} represents a confidence level of 90%.
Date: September 28, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Branching Fraction for B+ -> pi0 l+ nu, Measured in Upsilon (4S) -> BBbar Events Tagged by B- -> D0 l- nubar (X) Decays

Description: We report a preliminary branching fraction of (1.80 {+-} 0.37{sub stat.} {+-} 0.23{sub syst.}) x 10{sup -4} for the charmless exclusive semileptonic B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu} decay, where {ell} can be either a muon or an electron. This result is based on data corresponding to an integrated luminosity of 81 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector. The analysis uses B{bar B} events that are tagged by a B meson reconstructed in the semileptonic B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}(X) decays, where X can be either a {gamma} or a {pi}{sup 0} from a D* decay.
Date: June 29, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department