| 51. |
- Ablikim, M., et al.
(författare)
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Determination of the absolute branching fractions of D0 → K-e+νe and D+ → K0e+νe
- 2021
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:5
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Tidskriftsartikel (refereegranskat)abstract
- Using 2.93 fb(-1) of e(+)e(-) collision data collected with the BESIII detector at a center-of-mass energy of 3.773 GeV, we measure the absolute branching fractions of the decays D-0 -> K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) to be (3.567 +/- 0.031(stat) +/- 0.025(syst))% and (8.68 +/- 0.14(stat) +/- 0.16(syst))%, respectively. Starting with the process e(+)e(- ) -> D (D) over bar, a new reconstruction method is employed to select events that contain candidates for both D -> (K) over bare(+)nu(e) and (D) over bar -> Ke(-)(nu) over bar (e) decays. The branching fractions reported in this work are consistent within uncertainties with previous BESIII measurements that selected events containing D -> (K) over bare(+)nu(e) and hadronic (D) over bar decays. Combining our results with the lifetimes of the D degrees and D+ mesons and the previous BESIII measurements leads to a ratio of the two decay partial widths of (Gamma) over bar (D0 -> K-e+)(nu e)/(Gamma) over bar (D+ -> (K) over bar 0e+)(nu e) = 1.039 +/- 0.021. This ratio supports isospin symmetry in the D-0 -> K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) decays within 1.9 sigma.
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| 52. |
- Ablikim, M., et al.
(författare)
-
Determination of the Λ+c spin via the reaction e+e− → Λc¯Λc
- 2021
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:9
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a comparison of two possible Λ+c spin hypotheses, J=½ and 3/2, via the process e+e− → Λ+c¯Λ−c, using the angular distributions of Λ+c decays into pK0S, Λπ+, Σ0π+, and Σ+π0. The data were recorded at √s=4.6 GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb−1. The Λ+c spin is determined to be J=½, with this value favored over the 3/2 hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
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| 53. |
- Ablikim, M., et al.
(författare)
-
Direct Measurement of the Branching Fractions B(psi(3686) -> J/psi X) and B(psi(3770) -> J/psi X), and Observation of the State R(3760) in e(+)e(-) -> J/psi X
- 2021
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:8
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Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the observed cross sections of e(+)e(-) -> J/psi X based on 3.21 fb(-1) of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(psi(3686 -> J/psi X) = (64.4 +/- 0.6 +/- 1.6)% and B(psi(3770) -> J/psi X) = (0.5 +/- 0.2 +/- 0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays psi(3686) -> J/psi X and psi(3770) -> J/psi X. Instead, it can be better described with one more BW amplitude of the decay R(3760) -> J/psi X. Under this assumption, we extracted the R(3760) mass M-R(3760) = 3766.2 +/- 3.8 +/- 0.4 MeV/c(2), total width Gamma(tot)(R(3760)) = 22.2 +/- 5.9 +/- 1.4 MeV, and product of leptonic width and decay branching fraction Gamma(ee)(R(3760)) B[R(3760) -> J/psi X] = (79.4 +/- 85.5 +/- 11.7) eV. The significance of the R(3760) is 5.3 sigma. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.
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| 54. |
- Ablikim, M., et al.
(författare)
-
First Measurement of Polarizations in the Decay D-0 -> omega phi
- 2022
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 128:1
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at a center-of-mass energy root s = 3.773 GeV by the BESIII detector, the decay D-0 -> omega phi is observed for the first time. The branching fraction is measured to be (6.48 +/- 10.9 +/- 1 0.40) x 10(-4) with a significance of 6.3 sigma, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the phi and omega mesons from the D-0 -> omega phi decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.
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| 55. |
- Ablikim, M., et al.
(författare)
-
First Measurement of the Absolute Branching Fraction of Λ→pμ−¯νμ
- 2021
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:12
-
Tidskriftsartikel (refereegranskat)abstract
- The absolute branching fraction of Lambda -> p mu(-)(upsilon) over bar (mu) is reported for the fast time based on an e(+)e(-) annihilation sample of 10 x 10(9) J/psi events collected with the BESIII detector at N rs = 3.097 GeV. The branching fraction is determined to be B(Lambda -> p mu(-)(upsilon) over bar (mu)). [1.48 +/- 0.21(stat) +/- 0.08(syst)] x 10(-4), which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Lambda -> pe(-)(upsilon) over bar (e)), we obtain the ratio {[Gamma(Lambda -> p mu(-)(upsilon) over bar (mu))]/[Gamma(Lambda -> pe(-)(upsilon) over bar (e))]} to be 0.178 +/- 0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Lambda -> p mu(-)(upsilon) over bar (mu) and (Lambda) over bar -> (p) over bar mu(+)upsilon(mu) is also determined, and no evidence for CP violation is found.
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| 56. |
- Ablikim, M., et al.
(författare)
-
First measurements of χcJ→Σ−¯Σ+(J=0,1,2) decays
- 2020
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 101:9
-
Tidskriftsartikel (refereegranskat)abstract
- We measured the branching fractions of the decays chi(cJ) -> Sigma(-)(Sigma) over bar (+) for the first time using the final states n (n) over bar pi(+)pi(-). The data sample exploited here is 448.1 x 10(6) psi(3686) events collected with BESIII. We find B(chi(cJ) -> Sigma(-)(Sigma) over bar (+)) = (51.3 +/- 2.4 +/- 4.1) x 10(-5), (5.7 +/- 1.4 +/- 0.6) x 10(-5), and (4.4 +/- 1.7 +/- 0.5) x 10(-5), for J = 0, 1, 2, respectively, where the first uncertainties are statistical and the second systematic.
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| 57. |
- Ablikim, M., et al.
(författare)
-
First Observation of D+ -> eta mu(+)nu(mu) and Measurement of Its Decay Dynamics
- 2020
-
Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:23
-
Tidskriftsartikel (refereegranskat)abstract
- By analyzing a data sample corresponding to an integrated luminosity of 2.93 fb(-1) collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D+ -> eta mu(+) nu(mu) decay to be BD+ ->eta mu+nu mu = (10.4 +/- 1.0(stat) +/- 0.5(syst)) x 10(-4). Using the world averaged value of BD+ ->eta e+nu e, the ratio of the two branching fractions is determined to be = BD+ ->eta mu+nu mu/BD+ ->eta e+nu e =0.91 +/- 0.13((stat+syst)), which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f(+)(eta)(0) and the c -> d Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cd vertical bar to be f(+)(eta)(0)vertical bar V-cd vertical bar = 0.087 +/- 0.008(stat) +/- 0.002(syst). Taking the input of vertical bar V-cd vertical bar from the global fit in the standard model, we determine f(+)(eta)(0) = 0.39 +/- 0.04(stat) +/- 0.01(syst). On the other hand, using the value of f(+)(eta)(0) calculated in theory, we find vertical bar V-cd vertical bar= 0.242 +/- 0.022(stat )+/- 0.006(syst) +/- 0.033(theory).
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| 58. |
- Ablikim, M., et al.
(författare)
-
First observation of the decay chi(cJ) -> Sigma(+)(p)over-barK(S)(0)+ c.c. (J=0,1,2)
- 2019
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 100:9
-
Tidskriftsartikel (refereegranskat)abstract
- Using E1 radiative transitions psi(3686) -> gamma chi(cJ) from a sample of (448.1 +/- 2.9) x 10(6) psi(3686) events collected with the BESIII detector, the decays chi(cJ) -> Sigma(+)(p) over barK(S)(0) + c.c.(J = 0,1,2) are studied. The decay branching fractions are measured to be B(chi(c0) -> Sigma(+)(p) over barK(S)(0) + c.c.) = (3.52 +/- 0.19 +/- 0.21) x 10(-4), B(chi(c1) -> Sigma(+)(p) over barK(S)(0) + c.c.) = (1.53 +/- 0.10 +/- 0.08) x 10(-4), and B(chi(c2) -> Sigma(+)(p) over barK(S)(0) + c.c.) = (8.25 +/- 0.83 +/- 0.49) x 10(-5), where the first and second uncertainties are the statistical and systematic ones, respectively. No evident intermediate resonances arc observed in the studied processes.
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| 59. |
- Ablikim, M., et al.
(författare)
-
First Observation of the Direct Production of the χc1 in e+e− Annihilation
- 2022
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 129:12
-
Tidskriftsartikel (refereegranskat)abstract
- We study the direct production of the JPC=1++ charmonium state χc1(1P) in electron-positron annihilation by carrying out an energy scan around the mass of the χc1(1P). The data were collected with the BESIII detector at the BEPCII collider. An interference pattern between the signal process e+e−→χc1(1P)→γJ/ψ→γμ+μ− and the background processes e+e−→γISRJ/ψ→γISRμ+μ− and e+e−→γISRμ+μ− is observed by combining all the data samples. The χc1(1P) signal is observed with a significance of 5.1σ. This is the first observation of a C-even state directly produced in e+e− annihilation. The electronic width of the χc1(1P) resonance is determined to be Γee=(0.12+0.13−0.08) eV, which is of the same order of magnitude as theoretical calculations.
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| 60. |
- Ablikim, M., et al.
(författare)
-
First observations of h(c )-> hadrons
- 2019
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 99:7
-
Tidskriftsartikel (refereegranskat)abstract
- Based on (4.48 +/- 0.03) x 10(8) Psi(3686) events, collected with the BESIII detector at the BEPCII storage ring, five h(c) hadronic decays are searched for via the process Psi(3686) -> pi(0)h(c). Three of them, h(c) -> p (p) over bar pi(+)pi(-) , pi(+)pi(-)pi(0 )and 2(pi(+)pi(-))pi(0) are observed for the first time with significances of 7.4 sigma, 4.6 sigma, and 9.1 sigma, and their branching fractions are determined to be (2.89 +/- 0.32 +/- 0.55) x 10(-3), (1.60 +/- 0.40 +/- 0.32) x 10(-3), and (7.44 +/- 0.94 +/- 1.52) x 10(-3), respectively, where the first uncertainties are statistical and the second systematic. No significant signal is observed for the other two decay modes, and the corresponding upper limits of the branching fractions are determined to be B(h(c) -> 3(pi(+)pi(-))pi(0)) < 8.7 x 10(-3) and B(h(c) -> K+K-pi(+)pi(-) ) < 5.8 x 10(-4) at the 90% confidence level.
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