742 research outputs found
Measurement of the mass difference m(B-0)-m(B+)
No full textUsing 230 x 10(6) B (B) over bar events recorded with the BABAR detector at the e(+)e(-) storage rings PEP-II, we reconstruct approximately 4100 B-0 -> J/psi K+pi(-) and 9930 B+ -> J/psi K+ decays with J/psi -> mu(+)mu(-) and e(+)e(-). From the measured B-momentum distributions in the e(+)e(-) rest frame, we determine the mass difference m(B-0) - m(B+) = (+0.33 +/- 0.05 +/- 0.03) MeV/c(2)
Measurement of Collins asymmetries in inclusive production of charged pion pairs in e+e− annihilation at BABAR
Get PDFWe present measurements of Collins asymmetries in the inclusive process e+e−→ππX, where π stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb−1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis
Study of e[superscript +]e[superscript -]→pp̅ via initial-state radiation at BABAR
Get PDFThe process e[superscript +]e[superscript -]→pp̅ γ is studied using 469 fb[superscript -1] of integrated luminosity collected with the BABAR detector at the SLAC National Accelerator Laboratory, at an e[superscript +]e[superscript -] center-of-mass energy of 10.6 GeV. From the analysis of the pp̅ invariant mass spectrum, the energy dependence of the cross section for e[superscript +]e[superscript -]→pp̅ is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |G[subscript E]/G[subscript M]|, and the asymmetry in the proton angular distribution are measured for pp̅ masses below 3 GeV. The branching fractions for the decays J/ψ→pp̅ and ψ(2S)→pp̅ are also determined.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Study of e(+)e(-)->Lambda(Lambda)over-bar, Lambda(Sigma)over-bar(0), Sigma(0)(Sigma)over-bar(0) using initial state radiation with BABAR
Get PDFWe study the e(+)e(-)->Lambda(Lambda) over bar gamma, Lambda(Sigma) over bar (0)gamma, Sigma(0)(Sigma) over bar (0)gamma processes using 230 fb(-1) of integrated luminosity collected by the BABAR detector at e(+)e(-) center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e(+)e(-)->Lambda(Lambda) over bar, Lambda(Sigma) over bar (0), Sigma(0)(Sigma) over bar>(0) are measured in the dibaryon mass range from threshold up to 3 GeV/c(2). The ratio of electric and magnetic form factors, |G(E)/G(M)|, is measured for e(+)e(-)->Lambda(Lambda) over bar, and limits on the relative phase between Lambda form factors are obtained. We also measure the J/psi ->Lambda(Lambda) over bar, Sigma(0)(Sigma) over bar (0), and psi(2S)->Lambda(Lambda) over bar branching fractions
Forecasting the Philippine peso-US dollar exchange rate and its implicatins on the decision making of selected importers and exporters
No full textMeasurements of the tau mass and the mass difference of the tau(+) and tau(-) at BABAR
Get PDFWe 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(-)
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Measurement of the mass difference m(B0)-m(B+)
Get PDFUsing 230×106 BB̄ events recorded with the BABAR detector at the e+e- storage rings PEP-II, we reconstruct approximately 4100 B0→J/ψK+π- and 9930 B+→J/ψK+ decays with J/ψ→μ+μ- and e+e-. From the measured B-momentum distributions in the e+e- rest frame, we determine the mass difference m(B0)-m(B+)=(+0. 33±0.05±0.03)MeV/c2. © 2008 The American Physical Society
Measurements of branching fractions and CP asymmetries and studies of angular distributions for B→ϕϕK decays
Get PDFWe present branching fraction and CP asymmetry measurements as well as angular studies of B -> phi phi K decays using 464 x 10(6) B (B) over bar events collected by the BABAR experiment. The branching fractions are measured in the phi phi invariant mass range below the eta(c) resonance (m(phi phi) phi phi K(+)) = (5.6 +/- 0.5 +/- 0.3) x 10(-6) and B(B(0) -> phi phi K(0)) = (4.5 +/- 0.8 +/- 0.3) x 10(-6), where the first uncertainty is statistical and the second systematic. The measured direct CP asymmetries for the B(+/-) decays are A(CP) = -0.10 +/- 0.08 +/- 0: 02 below the eta(c) threshold (m(phi phi) < 2.85 GeV) and A(CP) = 0.09 +/- 0.10 +/- 0.02 in the eta(c) resonance region (m(phi phi) in [2.94, 3.02] GeV). Angular distributions are consistent with J(P) = 0(-) in the eta(c) resonance region and favor J(P) = 0(+) below the eta(c) resonance
Measurement of the mass and width of the D_{s1}(2536)^{+} meson
Get PDFThe decay width and mass of the Ds1(2536)+ meson are measured via the decay channel Ds1+→D*+KS0 using 385 fb-1 of data recorded with the BABAR detector in the vicinity of the Υ(4S) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is Γ(Ds1+)=0.92±0.03(stat.)±0.04(syst.) MeV. For the mass, a value of m(Ds1+)=2535.08±0.01(stat.)±0.15(syst.) MeV/c2 is obtained. The mass difference between the Ds1+ and the D*+ is measured to be m(Ds1+)-m(D*+)=524.83±0.01(stat.)±0.04(syst.) MeV/c2, representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the Ds1+ meson is confirme
The BaBar detector: Upgrades, operation and performance
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121729.pdf (Author’s version preprint ) (Open Access
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