Number of J/ψ events at BESIII Adlarson, P.; Ahmed, S.; Amoroso, A. ...
Chinese Physics C, High Energy Physics and Nuclear Physics/Chinese physics C,
07/2022, Letnik:
46, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Abstract
Using inclusive decays of
, a precise determination of the number of
events collected with the BESIII detector was performed. For the two data sets taken in 2009 and 2012, the numbers of
...events were recalculated to be
and
, respectively; these numbers are in good agreement with the previous measurements. For the
sample taken in 2017–2019, the number of events was determined to be
. The total number of
events collected with the BESIII detector was determined to be
, where the uncertainty is dominated by systematic effects, and the statistical uncertainty is negligible.
Based on 10 billion J/psi events collected at the BESIII experiment, a search for CP violation in Lambda decay is performed in the difference between CP-odd decay parameters alpha_ for Lambda -> p ...pi(-) and alpha(+) for (Lambda) over bar -> (p) over bar pi(+) by using the process e(+)e(-) -> J/psi -> Lambda(Lambda) over bar. With a five-dimensional fit to the full angular distributions of the daughter baryon, the most precise values for the decay parameters arc determined to be a_ = 0.7519 +/- 0.0036 +/- 0.0024 and alpha(+) = -0.7559 +/- 0.0036 +/- 0.0030, respectively. The Lambda and (Lambda) over bar averaged value of the decay parameter is extracted to be a(avg) = 0.7542 +/- 0.0010 +/- 0.0024 with unprecedented accuracy. The CP asymmetry A(CP) = (alpha_ + alpha(+))/(a_-alpha(+)) is determined to be -0.0025 +/- 0.0046 +/- 0.0012, which is one of the most precise measurements in the baryon sector. The reported results for the decay parameter will play an important role in the studies of the polarizations and CP violations for the strange, charmed and beauty baryons.
Using 448.0×106 ψ(3686) events collected with the BESIII detector, an amplitude analysis is performed for ψ(3686)→γχc1, χc1→ηπ+π− decays. The most dominant two-body structure observed is a0(980)±π∓; ...a0(980)±→ηπ±. The a0(980) line shape is modeled using a dispersion relation, and a significant nonzero a0(980) coupling to the η′π channel is measured. We observe χc1→a2(1700)π production for the first time, with a significance larger than 17σ. The production of mesons with exotic quantum numbers, JPC=1−+, is investigated, and upper limits for the branching fractions χc1→π1(1400)±π∓, χc1→π1(1600)±π∓, and χc1→π1(2015)±π∓, with subsequent π1(X)±→ηπ± decay, are determined.
We report an amplitude analysis and branching fraction measurement of D+s → K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV. We ...perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave line shape, followed by an amplitude analysis of our very pure high-statistics sample. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D+s → K+K− π+) = (5.47 ± 0.0 8stat ± 0.13sys)%.
Experiments at the Super Charm-Tau factory Achasov, Mikhail N.; Blinov, Vladimir E.; Bobrov, Alexander V. ...
Physics Uspekhi,
01/2024, Letnik:
67, Številka:
1
Journal Article
Abstract
From December 2019 to June 2021, the BESIII experiment collected approximately 5.85 fb
−1
of data at center-of-mass energies between 4.61 and 4.95 GeV. This is the highest collision energy ...BEPCII has reached to date. The accumulated
annihilation data samples are useful for studying charmonium(-like) states and charmed-hadron decays. By adopting a novel method of analyzing the production of
pairs in
annihilation, the center-of-mass energies are measured with a precision of
0.6 MeV. Integrated luminosities are measured with a precision of better than 1% by analyzing the events of large-angle Bhabha scattering. These measurements provide important inputs to analyses based on these data samples.
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