3,152 research outputs found
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Precision measurements of B[psi(3686) -> pi(+)pi(-)J/psi] and B[J/psi -> l(+)l(-)]
No full text<p>Based on (106.41 +/- 0.86) x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, the branching fractions of psi(3686) -> pi(+)pi(-)J/psi, J/psi -> e(+)e(-), and J/psi -> mu(+)mu(-) are measured. We obtain B[psi(3686) -> pi(+)pi(-)J/psi] = (34.98 +/- 0.02 +/- 0.45)%, B[J/psi -> e(+)e(-)] = (5.983 +/- 0.007 +/- 0.037)%, and B[J/psi -> mu(+)mu(-)] = (5.973 +/- 0.0007 +/- 0.038)%. The measurement of B[psi(3686) -> pi(+)pi(-)J/psi] confirms the CLEO-c measurement, and is apparently larger than the others. The measured J/psi leptonic decay branching fractions agree with previous experiments within one standard deviation. These results lead to B[J/psi -> l(+)l(-)] = (5.978 +/- 0.005 +/- 0.040)% by averaging over the e(+)e(-) and mu(+)mu(-) channels and a ratio of B[J/psi -> e(+)e(-)]/B[J/psi -> mu(+)mu(-)] = 1.0017 +/- 0.0017 +/- 0.0033, which tests e- mu universality at the four tenths of a percent level. All the measurements presented in this paper are the most precise in the world to date.</p>
Measurement of the branching fraction of J/psi -> omega eta 'pi(+)pi(-) and search for J/psi -> omega X(1835), X(1835) -> eta 'pi(+)pi(-) decay
No full textKolcu, Onur Buğra (Arel Author)Using a sample of 1.31 x 10(9) J/psi events collected by the BESIII detector at BEPCII during 2009 and 2012, we study the J/psi -> omega eta'pi(+)pi(-) thorn p-hadronic process. For the first time, we measure the branching ratio B(J/psi -> omega eta'pi(+)pi(-)) = (1.12 +/- 0.02 +/- 0.13) x 10(-3). We search for the X(1835) state in the eta'pi(+)pi(-) invariant mass spectra. No evidence is found and we estimate the upper limit on the branching fraction at 90% confidence level to be B(J/psi -> omega X(1835), X(1835) -> eta'pi(+)pi(-)) < 6.2 x 10(-5)
Study of j/psi -> eta phi pi(+)pi(-) at BESIII
No full textÇetin, Serkant Ali (Dogus Author)invariant mass spectrum of phi f(0)(980) with a statistical significance of greater than 10 sigma. The corresponding mass and width are determined to be M = 2200 +/- 6(stat) +/- 5(syst) MeV/c(2) and Gamma = 104 +/- 15(stat) +/- 15(syst) MeV, respectively, and the product branching fraction is measured to be B(J/psi ->eta Y(2175), Y(2175)->phi f(0)(980), f(0)(980)->pi(+)pi(-)) = (1.20 +/- 0.14(stat)+/- 0.37(syst))x10(-4). The results are consistent within errors with those of previous experiments. We also measure the branching fraction of J/psi ->phi f(1)(1285) with f(1)(1285)->eta pi(+)pi(-) and set upper limits on the branching fractions for J/psi ->phi eta(1405)/phi X(1835)/phi X(1870) with eta(1405)/X(1835)/X(1870)->eta pi(+)pi(-) at the 90% confidence level
Studies on pi(+)pi(-) phase motion in the Psi(')-> J/Psi pi(+)pi(-) process
No full textWe propose a measurement of the elastic pi pi scattering phase-shift difference delta(0)(0)-delta(2)(0) through the Psi(')-> J/Psi pi(+)pi(-) process in the future high statistics BES-III experiment. The decay amplitude is constructed with seven Lorentz invariant form factors and is compared with their theoretical estimation. Based on a Monte Carlo study, it is found that the phase-shift difference can be indeed recovered and, hence, it is expected to be measured in the energy region between 350 and 550 MeV at future BES-III.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)1ARTICLE7null7
Measurements of J/psi decays into 2(pi(+)pi(-))eta and 3(pi(+)pi(-))eta
No full textBased on a sample of 5.8 x 10(7) J/psi events taken with the BESII detector, the branching fractions of J/psi -> 2(pi(+)pi(-))eta and J/psi -> 3(pi(+)pi(-))eta are measured for the first time to be (2.26 +/- 0.08 +/- 0.27) x 10(-3) and (7.24 +/- 0.96 +/- 1.11) x 10(-4), respectively. (c) 2005 Elsevier B.V. All rights reserved.Physics, MultidisciplinarySCI(E)6ARTICLE3-4192-19861
Partial wave analyses of J/psi ->gamma pi(+)pi(-) and gamma pi(0)pi(0)
No full textResults are presented on J/psi radiative decays to pi(+)pi(-) and pi(0)pi(0) based on a sample of 58M J/psi events taken with the BES II detector. Partial wave analyses are carried out using the relativistic covariant tensor amplitude method in the 1.0 to 2.3 GeV/c(2) pi pi mass range. There are conspicuous peaks due to the f(2)(1270) and two 0(++) states in the 1.45 and 1.75 GeV/c(2) mass regions. The first 0(++) state has a mass of 1466 +/- 6 +/- 20 MeV/c(2), a width of 108(-11)(+14) +/- 25 MeV/c(2), and a branching fraction B(J/psi -> gamma f(0)(1500) -> gamma pi(+)pi(-)) = (0.67 +/- 0.02 +/- 0.30) x 10(-4). Spin 0 is strongly preferred over spin 2. The second 0(++) state peaks at 1765(-3)(+4) +/- 13 MeV/c(2) with a width of 145 +/- 8 +/- 69 MeV/c(2). If this 0(++) is interpreted as coming from f(0)(1710), the ratio of its branching fractions to pi pi and K (K) over bar is 0.41(-0.17)(+0.11). (c) 2006 Elsevier B.V. All rights reserved.Physics, MultidisciplinarySCI(E)0ARTICLE5-6441-44864
Study of J/psi -> eta phi pi(+)pi(-) at BESIII
No full textinvariant mass spectrum of phi f(0)(980) with a statistical significance of greater than 10 sigma. The corresponding mass and width are determined to be M = 2200 +/- 6(stat) +/- 5(syst) MeV/c(2) and Gamma = 104 +/- 15(stat) +/- 15(syst) MeV, respectively, and the product branching fraction is measured to be B(J/psi ->eta Y(2175), Y(2175)->phi f(0)(980), f(0)(980)->pi(+)pi(-)) = (1.20 +/- 0.14(stat)+/- 0.37(syst))x10(-4). The results are consistent within errors with those of previous experiments. We also measure the branching fraction of J/psi ->phi f(1)(1285) with f(1)(1285)->eta pi(+)pi(-) and set upper limits on the branching fractions for J/psi ->phi eta(1405)/phi X(1835)/phi X(1870) with eta(1405)/X(1835)/X(1870)->eta pi(+)pi(-) at the 90% confidence level
Observation of a structure at 1.84 GeV/c(2) in the 3(pi(+)pi(-)) mass spectrum in J/psi -> gamma 3(pi(+) pi(-)) decays
No full text<p>With a sample of 225.3 x 10(6) J/psi events taken with the BESIII detector, the decay J/psi -> gamma 3(pi(+) pi(-)) is analyzed. A structure at 1.84 GeV/c(2) is observed in the 3(pi(+) pi(-)) invariant mass spectrum with a statistical significance of 7.6 sigma. The mass and width are measured to be M = 1842.2 +/- 4.2(-2.6)(+7.1) MeV/c(2) and Gamma = 83 +/- 14 +/- 11 MeV. The product branching fraction is determined to be B(J/psi -> gamma X(1840) x B(X(1840) -> 3(pi(+)pi(-))) = (2.44 +/- 0.36(-0.74)(+0.60)) x 10(-5). No eta' signals are observed in the 3(pi(+) pi(-)) invariant mass spectrum, and the upper limit of the branching fraction for the decay eta' -> 3(pi(+) pi(-)) is set to be 3.1 x 10(-5) at a 90% confidence level.</p>
Measurement of the branching fractions of psi(2S)-> 3(pi(+)pi(-)) and J/psi -> 2(pi(+)pi(-))
No full textUsing data samples collected at root s=3.686 GeV and 3.650 GeV by the BESII detector at the BEPC, the branching fraction of psi(2S)-> 3(pi(+)pi(-)) is measured to be [5.45 +/- 0.42(stat)+/- 0.87(syst)] x 10(-4), and the relative branching fraction of J/psi -> 2(pi(+)pi(-)) to that of J/psi ->mu(+)mu(-) is measured to be [6.01 +/- 0.20(stat)+/- 0.48(syst)]% via psi(2S)->pi(+)pi(-)J/psi, J/psi -> 2(pi(+)pi(-)). The electromagnetic form factor of 3(pi(+)pi(-)) is determined to be 0.19 +/- 0.02 and 0.24 +/- 0.02 at root s=3.650 GeV and 3.686 GeV, respectively.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)4ARTICLE1null7
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