Search results for " Anni"
showing 10 items of 847 documents
Study of thee+e−→π+π−π0process using initial state radiation withBABAR
2004
The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19…
Observation ofB+→ηρ+and search forB0decays toη′η,ηπ0,η′π0, andωπ0
2008
We present measurements of branching fractions for five B-meson decays to two-body charmless final states. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 459x10{sup 6} BB pairs. The results for branching fractions are, in units of 10{sup -6} (upper limits at 90% C.L.), B(B{sup +}{yields}{eta}{rho}{sup +})=9.9{+-}1.2{+-}0.8, B(B{sup 0}{yields}{eta}{sup '}{eta})=0.5{+-}0.4{+-}0.1(<1.2), B(B{sup 0}{yields}{eta}{pi}{sup 0})=0.9{+-}0.4{+-}0.1(<1.5), B(B{sup 0}{yields}{eta}{sup '}{pi}{sup 0})=0.9{+-}0.4{+-}0.1(<1.5), and B(B{sup 0}{yields}{omega}{pi}{sup 0})=0.07{+-}0.26{+-}0.02(<0.5). The first error quoted is statistical and the second systemati…
Study of hadronic transitions betweenΥstates and observation ofΥ(4S)→ηΥ(1S)decay
2008
We present a study of hadronic transitions between Υ(mS) (m = 4, 3, 2) and Υ(nS) (n = 2, 1) resonances based on 347.5 fb^(-1) of data taken with the BABAR detector at the PEP-II storage rings. We report the first observation of Υ(4S) → ηΥ(1S) decay with a branching fraction [script B](Υ(4S) → ηΥ(1S)) = (1.96±0.06_(stat)±0.09_(syst))×10^(-4) and measure the ratio of partial widths Γ(Υ(4S) → ηΥ(1S))/Γ(Υ(4S) → π^+π^-Υ(1S))=2.41±0.40_(stat)±0.12_(syst). We set 90% CL upper limits on the ratios Γ(Υ(2S) → ηΥ(1S))/Γ(Υ(2S) → π^+π^-Υ(1S))<5.2×10^(-3) and Γ(Υ(3S) → ηΥ(1S))/Γ(Υ (3S) → π^+π^-Υ(1S))<1.9×10^(-2). We also present new measurements of the ratios Γ(Υ(4S) → π^+π^-Υ(2S))/Γ(Υ(4S) → π^+ π^-Υ(1S)…
Observation of the rare decayB+→K+π0π0and measurement of the quasi-two-body contributionsB+→K*(892)+π0,B+→f0(980)K+, andB+→χc0K+
2011
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. Add…
Measurement of theB→D¯(*)D(*)Kbranching fractions
2011
The authors present a measurement of the branching fractions of the 22 decay channels of the B{sup 0} and B{sup +} mesons to {bar D}{sup (*)}D{sup (*)}K, where the D{sup (*)} and {bar D}{sup (*)} mesons are fully reconstructed. Summing the 10 neutral modes and the 12 charged modes, the branching fractions are found to be {Beta}(B{sup 0} {yields} {bar D}{sup (*)}D{sup (*)}K) = (3.68 {+-} 0.10 {+-} 0.24)% and {Beta}(B{sup +} {yields} {bar D}{sup (*)}D{sup (*)}K) = (4.05 {+-} 0.11 {+-} 0.28)%, where the first uncertainties are statistical and the second systematic. The results are based on 429 fb{sup -1} of data containing 471 x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance…
Measurements of the branching fractions for D+→KS0KS0K+, KS0KS0π+ and D0→KS0KS0, KS0KS0KS0
2017
Abstract By analyzing 2.93 fb − 1 of data taken at the ψ ( 3770 ) resonance peak with the BESIII detector, we measure the branching fractions for the hadronic decays D + → K S 0 K S 0 K + , D + → K S 0 K S 0 π + , D 0 → K S 0 K S 0 and D 0 → K S 0 K S 0 K S 0 . They are determined to be B ( D + → K S 0 K S 0 K + ) = ( 2.54 ± 0.05 s t a t . ± 0.12 s y s . ) × 10 − 3 , B ( D + → K S 0 K S 0 π + ) = ( 2.70 ± 0.05 s t a t . ± 0.12 s y s . ) × 10 − 3 , B ( D 0 → K S 0 K S 0 ) = ( 1.67 ± 0.11 s t a t . ± 0.11 s y s . ) × 10 − 4 and B ( D 0 → K S 0 K S 0 K S 0 ) = ( 7.21 ± 0.33 s t a t . ± 0.44 s y s . ) × 10 − 4 , where the second one is measured for the first time and the others are measured wit…
Study ofB-meson decays toηcK(*),ηc(2S)K(*), andηcγK(*)
2008
We study two-body B-meson decays to a charmonium state (eta(c), eta(c)(2S) or h(c)) and a K+ or K-*0(892) meson using a sample of 349 fb(-1) of data collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. We measure B(B-0 -> eta K-c*(0)) = (5.7 +/- 0.6(stat) +/- 0.9(syst)) x 10(-4), B(B-0 -> eta(c)(2S)K*(0)) h(c)K(+)) x B(h(c) -> eta(c)gamma) h(c)K*(0)) x B(h(c) -> eta(c)gamma) K (K) over bar pi) = (1.9 +/- 0.4(stat) +/- 1.1(syst))%. We also measure the mass and width of the eta(c) meson to be m(eta(c)) = (2985.8 +/- 1.5(stat) +/- 3.1(syst)) MeV/c(2) and Gamma(eta(c)) = (36.3(-3.6)(+3.7)(stat) +/- 4.4(syst)) MeV.
Measurement of theD*(2010)+natural linewidth and theD*(2010)+−D0mass difference
2013
We measure the mass difference, Δm_0, between the D^*(2010)^+ and the D^0 and the natural linewidth, Γ, of the transition D^*(2010)^+ → D^0π^+. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(4S) resonance, and correspond to an integrated luminosity of approximately 477 fb^(-1). The D^0 is reconstructed in the decay modes D^0 → K^-π^+ and D^0 → K^-π^+π^-π^+. For the decay mode D^0 → K^-π^+ we obtain Γ=(83.4±1.7±1.5) keV and Δm_0=(145425.6±0.6±1.8) keV, where the quoted errors are statistical and systematic, respectively. For the D^0 → K^-π^+π^-π^+ mode we obtain Γ=(83.2±1.5±2.6) keV and Δm_0 = (145426.6±0.5±2.0) keV. The combined measurements…
Measurement of theηandη′transition form factors atq2=112 GeV2
2006
We report a study of the processes e^+e^-→ηγ and e^+e^-→η′γ at a center-of-mass energy of 10.58 GeV, using a 232 fb^(-1) data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20_(-5)^(+6)ηγ and 50_(-7)^(+8)η′γ events over small backgrounds, and measure the cross sections σ(e^+e^-→ηγ)=4.5_(-1.1)^(+1.2)±0.3 fb and σ(e^+e^-→η′γ)=5.4±0.8±0.3 fb. The corresponding transition form factors at q^2=112 GeV^2 are q^2|F_η(q^2)|=0.229±0.030±0.008 GeV, and q^2|F_η′(q^2)|=0.251±0.019±0.008 GeV, respectively.
Measurement of the KL→e+e−e+e− decay rate
2005
Abstract The decay rate of the long-lived neutral K meson into the e + e − e + e − final state has been measured with the NA48 detector at the CERN SPS. Using data collected in 1998 and 1999, a total of 200 events has been observed with negligible background. This observation corresponds to a branching ratio of Br ( K L → e + e − e + e − ) = ( 3.30 ± 0.24 stat ± 0.23 syst ± 0.10 norm ) × 10 −8 .