Using 5.9 pb(-1) of e(+)e(-) annihilation data collected at center-of-mass energies from 3.640 to 3.701 GeV with the BESIII detector at the BEPCII Collider, we measure the observed cross sections of ...e(+)e(-) -> (KSX)-X-0 (where X = anything). From a fit to these observed cross sections with the sum of continuum and psi(3686) and J/psi Breit-Wigner functions and considering initial state radiation and the BEPCII beam energy spread, we obtain for the first time the product of psi(3686) leptonic width and inclusive decay Physics Letters 820 (2021) 136576 branching fraction Gamma B-ee(psi)(3686)(psi(3686) -> (KSX)-X-0) = (373.8 +/- 6.7 +/- 20.0) eV, and assuming Gamma(ee)(psi)((3686)) is (2.33 +/- 0.04) keV from PDG value, we measure B(psi(3686) ->(KSX)-X-0) = (16.04 +/- 0.29 +/- 0.90)%, where the first uncertainty is statistical and the second is systematic.
Born cross sections for the processes e(+)e(-) -> omega eta and e(+)e(-) -> omega pi(0) have been determined for centerof-mass energies between 2.00 and 3.08GeVwith the BESIII detector at the ...BEPCII collider. The results obtained in this work are consistent with previous measurements but with improved precision. Two resonant structures are observed. In the e(+)e(-) -> omega eta cross sections, a resonance with a mass of (2176 +/- 24 +/- 3) MeV/c(2) and a width of (89 +/- 50 +/- 5) MeV is observed with a significance of 6.2 sigma. Its properties are consistent with the phi(2170). In the e(+)e(-) -> omega pi(0) cross sections, a resonance denoted Y (2040) is observed with a significance of more than 10 sigma. Its mass and width are determined to be (2034 +/- 13 +/- 9) MeV/c(2) and (234 +/- 30 +/- 25) MeV, respectively, where the first uncertainties are statistical and the second ones are systematic. (C) 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license.
By using 6.32 fb(-1) of data collected with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we perform an amplitude analysis of the decay D-s(+) -> K-S(0) pi(+)pi(0) ...and determine the relative fractions and phase differences of different intermediate processes, which include K-S(0) rho(770)(+), K-S(0)rho(1450)(+), K*(892)(0) pi(+), K* (892)(+) pi(0), and K* (1410)(0) pi(+). With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D-s(+) -> K-S(0) pi(+) pi(0)) = (5.43 +/- 0.30(stat) +/- 0.15(syst)) x 10(-3).
Using a total of 5.25 fb(-1) of e(+)e(-) collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the process e(+)e(-)-> eta psi(2S) with a ...statistical significance of 4.9 standard deviations. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.
By analyzing 4.48 x 10(8) psi(3686) events collected with the BESIII detector, we observe the decays chi(cJ) -> nK(S)(0) (Lambda) over bar + c.c. (J = 0, 1, 2) for the first time, via the ...radiative transition psi(3686) -> gamma chi(cJ). The branching fractions are determined to be (6.65 +/- 0.26(stat)+/- 0.41(syst)) x 10(-4), (1.66 +/- 0.12(stat) +/- 0.12(syst)) x 10(-4), and (3.58 +/- 0.16(stat) +/- 0.23(syst)) x 10(-4) for J = 0, 1, and 2, respectively.
The decays D → K − π + π + π − and D → K − π + π 0 are studied in a sample of quantum-correlated D¯D pairs produced through the process e + e − → ψ (3770) → D¯D, exploiting a data set collected by ...the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb − 1 . Here D indicates a quantum superposition of a D 0 and a D¯0 meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle γ of the Unitarity Triangle in B − → DK − decays at the LHCb and Belle II experiments. The coherence factors are determined to be R K 3 π = 0.52+0.12−0.10 and RKππ0 = 0 . 78 ± 0 . 04, with values for the average strong-phase differences that are δK3πD=(167+31−19)∘ and δKππ0D=(196+14−15)∘, where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the D → K − π + π + π − to yield results that will allow for a more sensitive measurement of γ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6°.
Using 10.1 x 10(9)J/ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy <mml:msqrt>s</mml:msqrt> = 3.097 GeV and collected with the BESIII ...detector, we present a search for the rare semi-leptonic decay J/psi -> D(-)e(+)nu (e) + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction B(J/psi -> D(-)e(+)nu (e)+c. c.)<7.1x10(-8) is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.
We present a search for the lepton flavor violating decay J/psi -> e(+/-)mu(-/+) using 8.998 x 10(9)J/psi events collected with the BESIII detector at the BEPCII e(+)e(-) storage ring. No excess ...of signal above background is observed; we therefore set an upper limit on the branching fraction of B(J/psi -> e(+/-)mu(-/+)) < 4.5 x 10(-9) at the 90% confidence level. Improving the previous best result by a factor of more than 30, this measurement places the most stringent limit to date on lepton flavor violation in the heavy quarkonium sector.
We report a study of the e(+)e(-) -> D+D-pi(+)pi(-) process using e(+)e(-) collision data samples with an integrated luminosity of 2.5 fb(-1) at center-of-mass energies from 4.36 to 4.60 GeV, ...collected with the BESIII detector at the BEPCII storage ring. The D1(2420)+ is observed in the D+pi(+)pi(-) mass spectrum. The mass and width of the D-1(2420)+ are measured to be (2427.2 +/- 1.0(stat).+/- 1.2(syst).) MeV/c(2) and (23.2 +/- 2.3(stat). +/- 2.3(syst).) MeV, respectively. In addition, the Born cross sections of the e(+)e(-) -> D-1(2420)D-+(-) + c.c. -> D+D-pi(+)pi(-) and e(+)e(-) -> psi(3770)pi(+)pi(-) -> D+D-pi(+)pi(-) processes are measured as a function of the center-of-mass energy. (c) 2020 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
We report the first measurement of the absolute branching fraction of the inclusive decay Lambda c+-> KS0X. The analysis is performed using an e+e- collision data sample corresponding to an ...integrated luminosity of 567 pb-1 taken at <mml:msqrt>s</mml:msqrt> = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored Lambda <overbar></mml:mover>c- decay modes and the double-tag technique, this absolute branching fraction is measured to be B(Lambda c+-> KS0X)=(9.9 +/- 0.6 +/- 0.4)%, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is (18.7 +/- 8.3)<mml:mo>%, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.
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