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| 2. |
- Ablikim, M., et al.
(författare)
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Observation of J/psi -> gamma eta pi(0)
- 2016
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Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:7
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Tidskriftsartikel (refereegranskat)abstract
- We present the first study of the process J/psi -> gamma eta pi(0) using (223.7 +/- 1.4) x 10(6) J/psi events accumulated with the BESIII detector at the BEPCII facility. The branching fraction for J/psi -> gamma eta pi(0) is measured to be B(J/psi -> gamma eta pi(0)) = (2.14 +/- 0.18(stat) +/- 0.25(syst)) x 10(-5). With a Bayesian approach, the upper limits of the branching fractions B(J/psi -> gamma a(0)(980), a(0)(980) -> eta pi(0)) and B(J/psi -> gamma a(2)(1320), a(2)(1320) -> eta pi(0)) are determined to be 2.5 x 10(-6) and 6.6 x 10(-6) at the 95% confidence level, respectively. All of these measurements are given for the first time.
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| 3. |
- Ablikim, M., et al.
(författare)
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Improved measurement of the absolute branching fraction of D+ -> (K)over-bar(0)mu(+)nu(mu)
- 2016
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Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 76:7
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Tidskriftsartikel (refereegranskat)abstract
- By analyzing 2.93 fb(-1) of data collected at root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction B(D+ -> (K) over bar (0) (+)(mu)nu(mu)) = (8.72 +/- 0.07(stat). +/- 0.18(sys).) %, which is consistent with previous measurements within uncertainties but with significantly improved precision. Combining the Particle Data Group values of B(D-0 -> K- mu(+)nu(mu)), B(D+-> (K) over bar (0)e(+)nu(e)), and the lifetimes of the D-0 and D+ mesons with the value of B(D+ -> (K) over bar (0)mu(+)nu(mu)) measured in this work, we determine the following ratios of partial widths: Gamma (D-0 -> (K) over bar (-)mu(+)nu(mu))/Gamma (D+ -> (K) over bar (0)mu+nu(mu)) = 0.963 +/- 0.044 and Gamma (D+ -> (K) over bar (0) mu+nu(mu))/Gamma(D+ -> (K) over bar (0)e+nu(e)) = 0.988 +/- 0.033.
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| 4. |
- Ablikim, M., et al.
(författare)
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Measurement of Singly Cabibbo Suppressed Decays Lambda(+)(c) -> p pi(+)pi(-) and Lambda(+)(c) -> pK(+)K(-)
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:23
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Tidskriftsartikel (refereegranskat)abstract
- Using 567 pb(-1) of data collected with the BESIII detector at a center-of-mass energy of root s = 4.599 GeV, near the Lambda(+)(c)->(Lambda) over bar (-)(c) threshold, we study the singly Cabibbo-suppressed decays Lambda c(+) -> p pi(+) pi(-) and Lambda(+)(c) -> pK(+) K- By normalizing with respect to the Cabibbo-favored decay Lambda(+)(c)-> p pi(+)pi(-) we obtain ratios of branching fractions: [B(Lambda(+)(c) -> p pi(+)pi(-))/B(Lambda(+)(c) -> pK(-)pi(+))] = (6.70 +/- 0.48 +/- 0.25)% [B Lambda(+)(c) -> p phi)/B(Lambda(+)(c) -> pK(-)pi(+))] = (1.81 +/- 0.33 +/- 0.13)%,and [B(Lambda(+)(c) -> pK(+)K(non-phi)(-)/B(Lambda(+)(c) -> pK(-)pi(+))] (9.36 +/- 2.22 +/- 0.71)x10(-3), where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay Lambda(+)(c) -> p pi(+)pi(-) is observed for the first time, and the precision of the branching fraction for Lambda(+)(c) -> pK(+)K(non-phi)(-) and Lambda(+)(c) -> p phi is significantly improved.
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| 5. |
- Ablikim, M., et al.
(författare)
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Measurement of the absolute branching fraction of D+ → K̅0 e+νe via K̅0 → π 0 π 0
- 2016
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Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:11
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Tidskriftsartikel (refereegranskat)abstract
- By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..
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| 6. |
- Ablikim, M., et al.
(författare)
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Measurement of the Ds<(+)-> l(+)ve branching fractions and the decay constant fDs
- 2016
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Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:7
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Tidskriftsartikel (refereegranskat)abstract
- Using 482 pb(-1) of e(+) e(-) collision data collected at a center-of-mass energy of root s = 4.009 GeV with the BESIII detector, we measure the branching fractions of the decays D-s(+) -> u(+)v(u) and D-s(+) -> tau(+)v(tau). By constraining the ratio of decay rates of Ds(+) to tau(+)v(u) and to u(+)v(u) to the Standard Model prediction, the branching fractions are determined to be B(D-s(+) -> u(+)v(u) = (0.495 +/- 0.067 +/- 0.026)% and B(D-s(+) -> tau(+)v(tau) = (4.83 +/- 0.65 +/- 0.26)% Using these branching fractions, we obtain a value for the decay constant f(Ds+) of (241.0 +/- 16.3 +/- 6.5) MeV, where the first error is statistical and the second systematic.
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| 7. |
- Ablikim, M., et al.
(författare)
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Measurements of the absolute branching fractions for D-s(+) -> eta e(+)nu(e) and D-s(+) -> eta ' e(+)nu(e)
- 2016
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Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:11
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Tidskriftsartikel (refereegranskat)abstract
- By analyzing 482 pb(-1) of e(+)e(-) collision data collected at root s = 4.009 GeV with the BESIII detector at the BEPCII collider, we measure the absolute branching fractions for the semileptonic decays D-s(+) -> eta e(+)nu(e) and D-s(+) -> eta ' e(+)nu(e) to be B(D-s(+) -> eta e(+)nu(e)) = (2.30 +/- 0.31 +/- 0.08)% and B(D-s(+) -> eta ' e(+)nu(e)) = (0.93 +/- 0.30 +/- 0.05)%, respectively, and their ratio B(D-s(+) -> eta ' e(+)nu(e)) / B(D-s(+) -> eta ' e(+)nu(e)) = 0.40 +/- 0.14 +/- 0.02, where the first uncertainties are statistical and the second ones are systematic. The results are in good agreement with previous measurements within uncertainties; they can be used to determine the eta-eta' mixing angle and improve upon the D-s(+) semileptonic branching ratio precision.
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| 8. |
- Ablikim, M., et al.
(författare)
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Observation of an Anomalous Line Shape of the eta 'pi(+)pi(-) Mass Spectrum near the p(p)over-bar Mass Threshold in J/psi -> gamma eta 'pi(+)pi(-)
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:4
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Tidskriftsartikel (refereegranskat)abstract
- Using 1.09 x 10(9) J/psi events collected by the BESIII experiment in 2012, we study the J / psi -> gamma eta'pi(+)pi(-) process and observe a significant abrupt change in the slope of the eta'pi(+)pi(-) invariant mass distribution at the proton-antiproton (p (p) over bar) mass threshold. We use two models to characterize the eta'pi(+)pi(-) line shape around 1.85 GeV/c(2): one that explicitly incorporates the opening of a decay threshold in the mass spectrum (Flatte formula), and another that is the coherent sum of two resonant amplitudes. Both fits show almost equally good agreement with data, and suggest the existence of either a broad state around 1.85 GeV/c(2) with strong couplings to the c final states or a narrow state just below the p (p) over bar mass threshold. Although we cannot distinguish between the fits, either one supports the existence of a p (p) over bar moleculelike state or bound state with greater than 7 sigma significance.
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| 9. |
- Ablikim, M., et al.
(författare)
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Observation of e(+)e(-) -> eta ' J/psi center-of-mass energies between 4.189 and 4.600 GeV
- 2016
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Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:3
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Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> eta' J/psi is observed for the first time with a statistical significance of 8.6 sigma at center-of-mass energy root s = 4.226 GeV and 7.3 sigma at root s = 4.258 GeV using data samples collected with the BESIII detector. The Born cross sections are measured to be (3.7 +/- 0.7 +/- 0.3) and (3.9 +/- 0.8 +/- 0.3) pb at root s = 4.226 and 4.258 GeV, respectively, where the first errors are statistical and the second systematic. Upper limits at the 90% confidence level of the Born cross sections are also reported at other 12 energy points.
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| 10. |
- Ablikim, M., et al.
(författare)
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Observation of h(c) Radiative Decay h(c) -> gamma eta ' and Evidence for h(c) -> gamma eta
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 116:25
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Tidskriftsartikel (refereegranskat)abstract
- A search for radiative decays of the P-wave spin singlet charmonium resonance h(c) is performed based on 4.48 x 10(8) psi' events collected with the BESIII detector operating at the BEPCII storage ring. Events of the reaction channels h(c) -> gamma eta' and gamma eta are observed with a statistical significance of 8.4 sigma and 4.0 sigma, respectively, for the first time. The branching fractions of h(c) -> gamma eta' and h(c) -> gamma eta' are measured to be B(h(c) -> gamma eta') = (1.52 +/- 0.27 +/- 0.29) x 10(-3) and B(h(c) -> gamma eta) = (4.7 +/- 1.5 +/- 1.4) x 10(-4), respectively, where the first errors are statistical and the second are systematic uncertainties.
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