Showing papers by "Prafulla Kumar Behera published in 2009"

Precise measurement of the e+e-→π+π-(γ) cross section with the initial-state radiation method at BABAR

Abstract: A precise measurement of the cross section for the process e^+e^- → K^+K^-(γ) from threshold to an energy of 5 GeV is obtained with the initial-state radiation (ISR) method using 232 fb^(-1) of data collected with the BABAR detector at e^+e^- center-of-mass energies near 10.6 GeV. The measurement uses the effective ISR luminosity determined from the e^+e^- → μ^+μ^-(γ)γ_(ISR) process with the same data set. The corresponding lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is found to be a_μ^(KK,LO)=(22.93 ± 0.18_(stat) ± 0.22_(syst))×10^(-10). The charged kaon form factor is extracted and compared to previous results. Its magnitude at large energy significantly exceeds the asymptotic QCD prediction, while the measured slope is consistent with the prediction.

Measurement of time-dependent CP asymmetry in B0→cc̄K(*)0 decays

Abstract: We present updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465 +/- 5)x10(6) Upsilon(4S)-> B B decays collected with the BABAR detector at the PEP-II asymmetric energy e(+)e(-) storage rings operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured from J psi K-S(0), J psi K-L(0), psi(2S)K-S(0), eta K-c(S)0, chi K-c1(S)0, and J/psi K-*(892)(0) decays are: C-f=0.024 +/- 0.020(stat)+/- 0.016(syst) and -eta S-f(f)=0.687 +/- 0.028(stat)+/- 0.012(syst).

Study of DsJ decays to D*K in inclusive e+e- interactions

Abstract: We observe the decays D*_(s1)(2710)^+ → D*K and D*_(sJ)(2860)^+ → D*K and measure their branching fractions relative to the DK final state. We also observe, in the D*K mass spectrum, a new broad structure at a mass of (3044 ± 8_(stat)(^(+30)_(-5))_(syst)) MeV/c^2 having a width Γ =(239 ± 35_(stat)(^(+46)_(-42))_(syst)) MeV. To obtain this result we use 470 fb^(-1) of data recorded by the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.

Angular distributions in the decay B -> K*l(+)l(-)

Abstract: We use a sample of 384 million BBbar events collected with the Babar detector at the PEP-II e+e- collider to study angular distributions in the rare decays B -> K* l+l-, where l+l- is either e+e- or mu+mu-. For low dilepton invariant masses, m(l+l-) 3.2$ GeV/c^2, we measure AFB=0.76 (+0.52,-0.32) +/- 0.07 FL=0.71 (+0.20,-0.22) +/- 0.04.

Direct CP, Lepton Flavor and Isospin Asymmetries in the Decays B->K(*)l+l-

Abstract: We measure branching fractions and integrated rate asymmetries for the rare decays B -> K((*))l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-), using a sample of 384x10(6) BB events collected with the BABAR detector at the PEP-II e(+)e(-) collider. We find no evidence for direct CP or lepton-flavor asymmetries. However, for dilepton masses below the J/psi resonance, we find evidence for unexpectedly large isospin asymmetries in both B -> Kl(+)l(-) and B -> K(*)l(+)l(-) which differ, respectively, by 3.2 sigma and 2.7 sigma, including systematic uncertainties, from the standard model expectations.

Expected performance of the ATLAS experiment - detector, trigger and physics

Abstract: A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

Measurement of the e(+)e(-) -> b(b)over-bar cross section between root s=10.54 and 11.20 GeV

Abstract: We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

Evidence for the ηb(1S) Meson in Radiative Υ(2S) Decay

Abstract: We have performed a search for the eta_b(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6 million Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_gamma = 610.5 {+4.5} {-4.3} (stat) +/- 1.8 (syst) MeV, corresponding to an eta_b(1S) mass of 9392.9 {+4.6} {-4.8} (stat) +/- 1.9 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) --> gamma eta_b(1S) is determined to be (4.2 {+1.1} {-1.0} (stat) +/- 0.9 (syst)) x 10^(-4). The ratio B(Upsilon(2S) --> gamma eta_b(1S))/B(Upsilon(3S) --> gamma eta_b(1S)) = 0.89 {+0.25} {-0.23} (stat) {+0.12}{-0.16} (syst) is consistent with the ratio expected for magnetic dipole transitions to the eta_b(1S) meson.

Exclusive initial-state-radiation production of the DD¯, D*D¯, and D*D¯* systems

Abstract: We perform a study of the exclusive production of in initial-state-radiation events, from e(+)e(-) annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of 384 fb(-1) and was recorded by the BABAR experiment at the PEP-II storage rings. The D (D) over bar, D*(D) over bar, D*(D) over bar* mass spectra show clear evidence of several psi resonances. However, there is no evidence for Y(4260) -> D*(D) over bar or Y(4260) -> D*(D) over bar*.

Time-dependent amplitude analysis of B0 -> KS0π+π-

Abstract: We perform a time-dependent amplitude analysis of B^0→K_S^0π^+π^- decays to extract the CP violation parameters of f_0(980)K_S^0 and ρ^0(770)K_S^0 and the direct CP asymmetry of K^(*+)(892)π^-. The results are obtained from a data sample of (383±3)×10^6 BB decays, collected with the BABAR detector at the PEP-II asymmetric–energy B factory at SLAC. We find two solutions, with an equivalent goodness-of-fit. Including systematic and Dalitz plot model uncertainties, the combined confidence interval for values of the CP parameter β_(eff) in B^0 decays to f_0(980)K_S^0 is 18°<β_(eff)<76° at 95% confidence level (C.L). CP conservation in B^0 decays to f_0(980)K_S^0 is excluded at 3.5 standard deviations including systematic uncertainties. For B^0 decays to ρ^0(770)K_S^0, the combined confidence interval is -9°<β_(eff)<57° at 95% C.L. In decays to K^(*+)(892)π^- we measure the direct CP asymmetry to be A_(CP)=-0.20±0.10±0.01±0.02. The measured phase difference (including B^0B ^0 mixing) between decay amplitudes of B^0→K^(*+)(892)π^- and B ^0→K^(*-)(892)π^+, excludes the interval -137°<ΔΦ(K^(*+)(892)π^-)<-5° at 95% C.L.

Measurement of D0-D̄0 mixing using the ratio of lifetimes for the decays D0→K-π+ and K+K-

Abstract: We measure the rate of D^0-D ^0 mixing with the observable y_(CP)=(τ_(Kπ)/τ_(KK))-1, where τ_(KK) and τ_(Kπ) are, respectively, the mean lifetimes of CP-even D^0→K^+K^- and CP-mixed D^0→K^-π^+ decays, using a data sample of 384 fb^(-1) collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D^0 and D ^0 decays where the initial flavor of the decaying meson is not determined, we obtain y_(CP)=[1.12±0.26(stat)±0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3σ, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y_(CP) obtained from a sample of D^(*+)→D^0π^+ events, where the D^0 decays to K^-π^+, K^+K^-, and π^+π^-, which is disjoint with the untagged D^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_(CP)=[1.16±0.22(stat)±0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1σ.

Measurement of time dependent CP asymmetry parameters in B-0 meson decays to omega KS0, eta ' K-0, and pi(KS0)-K-0

Abstract: We present measurements of the time-dependent CP-violation parameters S and C in the decays B-0 -> omega K-S(0), B-0 -> eta'K-0, reconstructed as eta'K-S(0) and eta'K-L(0), and B-0 -> pi K-0(S)0. The data sample corresponds to the full BABAR dataset of 467 x 10(6) B (B) over bar pairs produced at the PEP-II asymmetric-energy e(+)e(-) collider at the Stanford Linear Accelerator Center. The results are S-omega KS0 = 0.55(-0.29)(+0.26) +/- 0.02, C-omega KS0 = 0.52(-0.20)(+0.22) +/- 0.03, S-eta'K0 = 0.57 +/- 0.08 +/- 0.02, C-eta'K0 = 0.08 +/- 0.06 +/- 0.02, S-pi 0KS0 = 0.55 +/- 0.20 +/- 0.03, and C-pi 0KS0 = 0.13 +/- 0.13 +/- 0.03, where the first errors are statistical and the second systematic. These results are consistent with our previous measurements and the world average of sin2 beta measured in B-0 -> J / psi K-S(0).

Measurement of semileptonic B decays into orbitally excited charmed mesons.

Abstract: We present a study of B decays into semileptonic final states containing charged and neutral D-1(2420) and D-2*(2460). The analysis is based on a data sample of 208 fb(-1) collected at the Y(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference Delta m = m(D**) - m(D) distribution. Product branching fractions are determined to be B(B+ -> D(1)(0)l(+)nu(l)) x B(D-1(0) -> D*+pi(-)) = (2.97 +/- 0.17 +/- 0.17) x 10(-3), B(B+ -> D-2*l(+)nu(e)) x B(D-2*(0) -> D(*)+pi(-)) = (2.29 +/- 0.23 +/- 0.21) x 10(-3), B(B-0 -> D(1)(-)l(+)nu(l)) x B(D-1(-) -> D*(0)pi(-)) = (2.78 +/- 0.24 +/- 0.25) x 10(-3) and B(B-0 -> D-2*(-)l(+)nu(l)) x B(D-2(*-) -> D-(*)0 pi(-)) = (1.77 +/- 0.26 +/- 0.11) x 10(-3). In addition we measure the branching ratio Gamma(D2* -> D pi(-))/Gamma(D-2* -> D-(*)pi(-)) = 0.62 +/- 0.03 +/- 0.02.

Measurements of the τ mass and the mass difference of the τ + and τ - at BABAR

Abstract: We present the result from a precision measurement of the mass of the tau lepton, M-tau, based on 423 fb(-1) of data recorded at the Upsilon(4S) resonance with the BABAR detector. Using a pseudomass endpoint method, we determine the mass to be 1776.68 +/- 0.12(stat)+/- 0.41(syst) MeV. We also measure the mass difference between the tau(+) and tau(-), and obtain (M-tau(+)-M-tau(-))/M-AVG(tau)=(-3.4 +/- 1.3(stat)+/- 0.3(syst))x10(-4), where M-AVG(tau) is the average value of M-tau(+) and M-tau(-).

Improved Measurement of B+→ρ+ρ0 and Determination of the Quark-Mixing Phase Angle α

Abstract: We present improved measurements of the branching fraction ${\cal B}$, the longitudinal polarization fraction $f_L$, and the direct {\ensuremath{CP}\xspace} asymmetry {\ensuremath{{\cal A}_{CP}}\xspace} in the $B$ meson decay channel $B^+\to\rho^+\rho^0$. The data sample was collected with the {{\slshape B\kern-0.1em{\smaller A}\kern-0.1em B\kern-0.1em{\smaller A\kern-0.2em R}}} detector at SLAC. The results are ${\cal B} (\Bp\ra\rprz)=(23.7\pm1.4\pm1.4)\times10^{-6}$, $f_L=0.950\pm0.015\pm0.006$, and $\Acp=-0.054\pm0.055\pm0.010$, where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the CKM weak phase angle $\alpha$ to be $(92.4^{+6.0}_{-6.5})^{\circ}$.

B meson decays to charmless meson pairs containing η or η′ mesons

Abstract: We present updated measurements of the branching fractions for B-0 meson decays to eta K-0, eta eta, eta phi, eta omega, eta K-'(0), eta(')eta('), eta(')phi, and eta(')omega, and branching fractions and CP-violating charge asymmetries for B+ decays to eta pi(+), eta K+, eta(')pi(+), and eta K-'(+). The data represent the full data set of 467x10(6) BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at the SLAC National Accelerator Laboratory. Besides large signals for the four charged B decay modes and for B-0 ->eta K-'(0), we find evidence for three B-0 decay modes at greater than 3.0 sigma significance. We find B(B-0 ->eta K-0)=(1.15(-0.38)(+0.43)+/- 0.09)x10(-6), B(B-0 ->eta omega)=(0.94(-0.30)(+0.35)+/- 0.09)x10(-6), and B(B-0 ->eta(')omega)=(1.01(-0.38)(+0.46)+/- 0.09)x10(-6), where the first (second) uncertainty is statistical (systematic). For the B+->eta K+ decay mode, we measure the charge asymmetry A(ch)(B+->eta K+)=-0.36 +/- 0.11 +/- 0.03.

Search for the rare leptonic decays B+ -> l(+) nu(l) (l = e, mu)

Abstract: We have performed a search for the rare leptonic decays B+ -> l(+) nu(l)(l = e, mu), using data collected at the Upsilon(4S) resonance by the BABAR detector at the PEP-II storage ring. In a sample of 468 x 10(6) B (B) over bar pairs we find no evidence for a signal and set an upper limit on the branching fractions B(B+ -> mu(+)nu(mu)) e(+) nu(e)) < 1.9 x 10(-6) at the 90% confidence level, using a Bayesian approach.

Model-independent search for the decay B+→l+νlγ

Abstract: We present a search for the radiative leptonic decay B^+ → l^+ν_lγ, where l = e, μ, using a data sample of 465 × 10^6 BB(overbar) pairs collected by the BABAR experiment. In this analysis, we fully reconstruct the hadronic decay of one of the B mesons in Υ(4S) → B^+B^- decays, then search for evidence of B^+ → l^+ν_lγ in the rest of the event. We observe no significant evidence of signal decays and report model-independent branching fraction upper limits of B(B^+ → e^+ν_eγ) < 17 × 10^(-6), B(B^+ → μ^+ν_μγ) < 24 × 10^(-6), and B(B^+ → l^+ν_lγ) < 15.6 × 10^(-6) (l= e or μ), all at the 90% confidence level.

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

Abstract: 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.

Branching fractions and CP-violating asymmetries in radiative B decays to eta K gamma

Abstract: We present measurements of the CP-violation parameters S and C for the radiative decay B^0 → ηK^0_Sγ for B → ηKγ we also measure the branching fractions and for B^+ → ηK^+γ the time-integrated charge asymmetry A_(ch). The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 × 10^6 BB pairs produced in e^+e^- annihilation. The results are S = -0.18^(+0.49)_(-0.46) ± 0.12, C = -0.32^(+0.40)_(-0.39) ± 0.07, B(B^0 → ηK^0γ) = (7.1^(+2.1)_(-2.0) ± 0.4) × 10^(-6), B(B^+ → ηK^+γ) = (7.7 ± 1.0 ± 0.4) × 10^(-6), and A_(ch) = (-9.0^(+10.4)_(-9.8) ± 1.4) × 10^(-2). The first error quoted is statistical and the second systematic.

Search for the decay B+→Ks0Ks0π+

Abstract: We search for charmless decays of charged B mesons to the three-body final state (KSKS0)-K-0 pi(+). Using a data sample of 423.7 fb(-1) collected at the Gamma(4S) resonance with the BABAR detector, corresponding to (465.1 +/- 5.1) x 10(6) (B) over bar B pairs, we find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10(-7).

Search for b→u transitions in B0→D0K*0 decays

Abstract: We present a study of the decays B^0 → D^(0)K^(*0) and B^0 →[overline D]^(0)K^(*0) with K^(*0) → K^(+)π^-. The D^0 and the [overline D]^0 mesons are reconstructed in the final states f = K^(+)π^-, K^(+)π^(-)π^0, K^(+)π^(-)π^(+)π^-, and their charge conjugates. Using a sample of 465 × 10^6 B[overline B] pairs collected with the BABAR detector at the PEP-II asymmetric-energy e^(+)e^(-) collider at SLAC, we measure the ratio R_(ADS) ≡ [Γ([overline B]^0 → [f]_D[overline K]^(*0)) + Γ(B^0 → [[overline f]]_(D)K^(*0))]/[Γ([overline B]^0 → [[overline f]]_(D)[overline K]^(*0)) + Γ(B^0 → [f]_(D)K^(*0))] for the three final states. We do not find significant evidence for a signal and set the following limits at 95% probability: R_(ADS)(Kπ) < 0.244, R_(ADS)(Kππ^0) < 0.181, and R_(ADS)(Kπππ) < 0.391. From the combination of these three results, we find that the ratio r_S between the b → u and the b → c amplitudes lies in the range [0.07,0.41] at 95% probability.

Use of Adaptive Resonance Theory for Vertical Handoff Decision in Heterogeneous Wireless Environment

Abstract: Designing of heterogeneous wireless environment involves several internetworking issues, such as seamless handoff or roaming, mobility management, security and accounting problem etc. One of the major issues in next- generation heterogeneous networks is the issue of vertical handoff for guaranteeing service continuity and quality of service. This paper reports on the design and implementation of multi-criteria vertical handoff decision algorithms in heterogeneous wireless environment. A neural network model has been used to process multi-criteria vertical handoff decision metrics.

Measurement of CP violation observables and parameters for the decays B±→DK*±

Abstract: We study the decay B--> DK*- using a sample of 379x10(6) Upsilon(4S)-> BB events collected with the BABAR detector at the PEP-II B factory. We perform a Gronau-London-Wyler analysis where the D meson decays into either a CP-even (CP+) eigenstate (K+K-, pi(+)pi(-)), CP-odd (CP-) eigenstate (K-S(0)pi(0), K-S(0)phi, K-S(0)omega) or a non-CP state (K-pi(+)). We also analyze D meson decays into K+pi(-) from a Cabibbo-favored D-0 decay or doubly suppressed D-0 decay [Atwood-Dunietz-Soni (ADS) analysis]. We measure observables that are sensitive to the Cabibbo-Kobayashi-Maskawa angle gamma: the partial-rate charge asymmetries A(CP +/-), the ratios R-CP +/- of the B-decay branching fractions in CP +/- and non-CP decay, the ratio R-ADS of the charge-averaged branching fractions, and the charge asymmetry A(ADS) of the ADS decays: A(CP+)=0.09 +/- 0.13 +/- 0.06, A(CP-)=-0.23 +/- 0.21 +/- 0.07, RCP+=2.17 +/- 0.35 +/- 0.09, RCP-=1.03 +/- 0.27 +/- 0.13, R-ADS=0.066 +/- 0.031 +/- 0.010, and A(ADS)=-0.34 +/- 0.43 +/- 0.16, where the first uncertainty is statistical and the second is systematic. Combining all the measurements and using a frequentist approach yields the magnitude of the ratio between the Cabibbo-suppressed and favored amplitudes, r(B)=0.31 with a one (two) sigma confidence level interval of [0.24, 0.38] ([0.17, 0.43]). The value r(B)=0 is excluded at the 3.3 sigma level. A similar analysis excludes values of gamma in the intervals [0, 7]degrees, [55, 111]degrees, and [175, 180]degrees ([85, 99]degrees) at the one (two) sigma confidence level.

Observation and polarization measurement of B0→a1(1260)+a1(1260)- decay

Abstract: We present measurements of the branching fraction B and longitudinal polarization fraction fL for B0→a1(1260)+a1(1260)- decays, with a1(1260)±→π-π+π±. The data sample, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represents 465×106 produced BB pairs. We measure B(B0→a1(1260)+a1(1260)-)×[B(a1(1260)+→π-π+π+)]2= (11.8±2.6±1.6)×10-6 and fL=0.31±0.22±0.10, where the first uncertainty is statistical and the second systematic. The decay mode is measured with a significance of 5.0 standard deviations including systematic uncertainties.

Search for B-meson decays to b1ρ and b1K*

Abstract: We present a search for decays of B mesons to final states with a b(1) meson and a rho or K*(d892) meson. The search is based on a data sample consisting of 465 million B (B) over bar pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0 x 10(-6) at the 90% confidence level, including systematic uncertainties.

Observation of the baryonic B-decay (B)over-bar(0) -> Lambda(+)(c)(p)over-barK(-)pi(+)

Abstract: 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.