Using (447.9 +/- 2.3) million (3686) events collected with the BESIII detector, the decays of chi(cJ) -> phi phi (J = 0, 1, 2) have been studied via the decay psi(3686) ->gamma chi(cJ). The ...branching fractions of the decays chi(cJ) -> phi phi (J = 0, 1, 2) are determined to be (8.59 +/- 0.27 +/- 0.20) x 10(-4), (4.26 +/- 0.13 +/- 0.15) x 10(-4), and (12.67 +/- 0.28 +/- 0. 33) x 10(-4), respectively, which are the most precise measurements to date. From a helicity amplitude analysis of the process psi(3686) -> gamma chi(cJ), chi(cJ) -> phi phi, phi -> K+K-, the polarization parameters of the chi(cJ) -> phi phi decays are determined for the first time.
With data samples collected with the BESIII detector at seven energy points at√s = 3.68 − 3.71 GeV, corresponding to an integrated luminosity of 333 pb−1, we presenta study of the Λ transverse ...polarization in the e+e− → Λ¯Λ reaction. The significanceof polarization by combining the seven energy points is found to be 2.6σ including thesystematic uncertainty, which implies a non-zero phase between the transition amplitudesof the Λ¯Λ helicity states. The modulus ratio and the relative phase of EM-psionic formfactors combined with all energy points are measured to be RΨ = 0.71+0.10−0.10 ± 0.03 and ∆ΦΨ= 23+8.8−8.0 ± 1.6 ◦ , where the first uncertainties are statistical and the second systematic.
Using a sample of (10.09 +/- 0.04) x 109 J/psi decays collected with the BESIII detector, partial wave analyses of the decay J/psi -> gamma(KSKS0)-K-0 pi(0) are performed within the (KSKS0)-K-0 ...pi(0) invariant mass region below 1.6 GeV/c(2). The covariant tensor amplitude method is used in both mass independent and mass dependent approaches. Both analysis approaches exhibit dominant pseudoscalar and axial vector components, and show good consistency for the other individual components. Furthermore, the mass dependent analysis reveals that the (KSKS0)-K-0 pi(0) invariant mass spectrum for the pseudoscalar component can be well described with two isoscalar resonant states using relativistic Breit-Wigner model, i.e., the eta(1405) with a mass of 1391.7 +/- 0.7(-0.3)(+11.3) MeV/c(2) and a width of 60.8 +/- 1.2(-12.0)(+5.5) MeV, and the eta(1475) with a mass of 1507.6 +/- 1.6(-32.2)(+15.5) MeV/c(2) and a width of 115.8 +/- 2.4(-10.9)(+14.8) MeV. The first and second uncertainties are statistical and systematic, respectively. Alternate models for the pseudoscalar component are also tested, but the description of the -10.9 invariant mass spectrum deteriorates significantly.
A partial wave analysis on the process e(+)e(-) -> omega(+)pi(-) is performed using 647 pb(-1) of data sample collected by using the BESIII detector operating at the BEPCII storage ring at ...center-of-mass (c.m.) energies from 2.000 GeV to 3.080 GeV. The Born cross section of the e(+)e(-) -> omega pi(+)pi(-) process is measured, with precision improved by a factor of 3 compared to that of previous studies. A structure near 2.25 GeV is observed in the energy-dependent cross sections of e(+)e(-) -> omega pi(+)pi(-) and omega pi(0)pi(0) with a statistical significance of 7.6 sigma, and its determined mass and width are 2232 +/- 19 +/- 27 MeV/c(2) and 93 +/- 53 +/- 20 MeV, respectively, where the first and second uncertainties are statistical and systematic, respectively. By analyzing the cross sections of subprocesses e(+)e(-) -> omega f(0)(500), omega f(0)(980), omega f(0)(1370), omega f(2)(1270), and b(1)(1235)pi, a structure, with mass M = 2200 +/- 11 +/- 17 MeV/c(2) and width Gamma = 74 +/- 20 +/- 24 MeV, is observed with a combined statistical significance of 7.9 sigma. The measured resonance parameters will help to reveal the nature of vector states around 2.25 GeV.
The decay Formula omitted is studied in a sample of quantum-correlated Formula omitted pairs, based on a data set corresponding to an integrated luminosity of 2.93 fb Formula omitted collected at the ...Formula omitted resonance by the BESIII experiment. The asymmetry between Formula omitted-odd and Formula omitted-even eigenstate decays into Formula omitted is determined to be Formula omitted, where the first uncertainty is statistical and the second is systematic. This measurement is an update of an earlier study exploiting additional tagging modes, including several decay modes involving a Formula omitted meson. The branching fractions of the Formula omitted modes are determined as input to the analysis in a manner that is independent of any strong phase uncertainty. Using the predominantly Formula omitted-even tag Formula omitted and the ensemble of Formula omitted-odd eigenstate tags, the observable Formula omitted is measured to be Formula omitted. The two asymmetries are sensitive to Formula omitted, where Formula omitted and Formula omitted are the ratio of amplitudes and phase difference, respectively, between the doubly Cabibbo-suppressed and Cabibbo-favoured decays. In addition, events containing Formula omitted tagged by Formula omitted are studied in bins of phase space of the three-body decays. This analysis has sensitivity to both Formula omitted and Formula omitted. A fit to Formula omitted, Formula omitted and the phase-space distribution of the Formula omitted tags yields Formula omitted, where external constraints are applied for Formula omitted and other relevant parameters. This is the most precise measurement of Formula omitted in quantum-correlated Formula omitted decays.
We report the first measurement of the absolute branching fraction of the inclusive decay Formula omitted. The analysis is performed using an Formula omitted collision data sample corresponding to an ...integrated luminosity of 567 Formula omitted taken at Formula omitted = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored Formula omitted decay modes and the double-tag technique, this absolute branching fraction is measured to be Formula omitted, 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 Formula omitted, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.
Observation of X Ablikim, M; Achasov, M. N; Adlarson, P ...
The European physical journal. C, Particles and fields,
08/2020, Letnik:
80, Številka:
8
Journal Article
Recenzirano
Using a sample of Formula omitted events collected with the BESIII detector, we perform a study of Formula omitted. X(2370) is observed in the Formula omitted invariant-mass distribution with a ...statistical significance of Formula omitted. Its resonance parameters are measured to be Formula omitted and Formula omitted. The product branching fractions for Formula omitted and Formula omitted are determined to be Formula omitted and Formula omitted, respectively. No evident signal for X(2120) is observed in the Formula omitted invariant-mass distribution. The upper limits for the product branching fractions of Formula omitted and Formula omitted are determined to be Formula omitted and Formula omitted at the 90% confidence level, respectively.
Based on e(+) e(-) collision samples corresponding to an integrated luminosity of 4.4 fb(-1) collected with the BESIII detector at center-of-mass energies between 4.6 GeV and 4.7 GeV, a partial wave ...analysis of the charmed baryon hadronic decay Lambda(+)(c) -> Lambda pi(+) pi(0) is performed, and the decays Lambda(+)(c) -> Lambda rho(770)(+) and Lambda(+)(c) -> Sigma(1385)pi are studied for the first time. Making use of the world-average branching fraction B(Lambda(+)(c) -> Lambda pi(+) pi(0)), their branching fractions are determined to be B(Lambda(+)(c) -> Lambda rho(770)(+)) = (4.06 +/- 0.30 +/- 0.35 +/- 0.23) x 10(-2), B(Lambda(+)(c) -> Sigma(1385)(+)pi(0)) = (5.86 +/- 0.49 +/- 0.52 +/- 0.35) x 10(-3), B(Lambda(+)(c) -> Sigma(1385)(0)pi(+)) = (6.47 +/- 0.59 +/- 0.66 +/- 0.38) x 10(-3), where the first uncertainties are statistical, the second are systematic, and the third are from the uncertainties of the branching fractions B(Lambda(+)(c) -> Lambda pi(+) pi(0)) and B(Sigma(1385) -> Lambda pi). In addition, the decay asymmetry parameters are measured to be alpha(Lambda rho)(770)+ = -0.763 +/- 0.053 +/- 0.045, alpha(Sigma(1385)+pi 0) = -0.917 +/- 0.069 +/- 0.056, and alpha(Sigma(1385)+0 pi)+ = -0.789 +/- 0.098 +/- 0.056.
The Born cross sections of the e(+)e(-) -> D*D+*(-) and e(+)e(-) -> D*D-+(-) processes are measured using e(+)e(-) collision data collected with the BESIII experiment at center-of-mass energies ...from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of 15.7 fb(-1). The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states.
By analyzing e(+)e(-) annihilation data corresponding to an integrated luminosity of 2.93 fb(-1) collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first ...observations of the doubly Cabibbo-suppressed decays D+ -> K+ pi(0)pi(0) and D+ -> K+ pi(0)eta. The branching fractions of D+ -> K+ pi(0)pi(0) and D+ -> K+ pi(0)eta are measured to be (2.1 +/- 0.4(stat) +/- 0.1(syst)) x 10(-4) and (2.1 +/- 0.5(stat) +/- 0.1(syst)) x 10(-4) with statistical significances of 8.8 sigma and 5.5 sigma, respectively. In addition, we search for the subprocesses D+ -> K*(892)(+)pi(0) and D+-> K*(892)(+)eta with K*(892)(+) -> K+pi(0). The branching fraction of D+ -> K* (892)(+)pi(0) is determined to be (4.4(-1.5stat)(+1.8) +/- 0.2(syst)) x 10(-4), with a statistical significance of 3.2 sigma. No significant signal for D+ -> K* (892)(+)pi(0) is found and we set an upper limit on the branching fraction of this decay at the 90% confidence level to be 5.4 x 10(-4).
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