The process $e^{+}e^{-} rightarrow phieta$ is studied at 22 center-of-mass energy points ($sqrt{s}$) between 2.00 and 3.08 GeV using 715 pb$^{-1}$ of data collected with the BESIII detector. The measured Born cross section of $e^{+}e^{-} rightarrow phieta$ is found to be consistent with {textsl{BABAR}} measurements, but with improved precision. A resonant structure around 2.175 GeV is observed with a significance of 6.9$sigma$ with mass ($2163.5pm6.2pm3.0$) MeV/$c^{2}$ and width ($31.1_{-11.6}^{+21.1}pm1.1$) MeV, where the first uncertainties are statistical and the second are systematic.
The Born cross sections for the process $e^+e^- to eta^prime pi^{+}pi^{-}$ at different center-of-mass energies between $2.00$ and $3.08$~GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of $6.3sigma$ and a mass and width of $M=(2108pm46pm25)$~MeV/$c^2$ and $Gamma=(138pm36pm30)$~MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in $e^+e^- to eta^prime pi^{+}pi^{-}$ and BESIII in $e^+e^- to omegapi^0$ within two standard deviations.
Born cross sections for the processes $e^+e^- to omegaeta$ and $e^+e^- to omegapi^{0}$ have been determined for center-of-mass energies between 2.00 and 3.08 GeV with 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 $e^{+}e^{-} to omegaeta$ cross sections, a resonance with a mass of $(2179 pm 21 pm 3)text{MeV}/c^2$ and a width of $(89 pm 28 pm 5)text{MeV}$ is observed with a significance of 6.1$sigma$. Its properties are consistent with the $phi(2170)$. In the $e^{+}e^{-} toomegapi^{0}$ 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 $(2034 pm 13 pm 9)text{MeV}/c^2$ and $(234 pm 30 pm 25)text{MeV}$, respectively, where the first uncertainties are statistical and the second ones are systematic.
The $e^+e^-toetagamma$ cross section has been measured in the center-of-mass energy range 1.07--2.00 GeV using the decay mode $etato 3pi^0$, $pi^0to gammagamma$. The analysis is based on 36 pb$^{-1}$ of integrated luminosity collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. The measured cross section of about 35 pb at 1.5 GeV is explained by decays of the $rho(1450)$ and $phi(1680)$ resonances.
Using data taken at 23 center-of-mass energies between 4.0 and 4.6 GeV with the BESIII detector at the BEPCII collider and with a total integrated luminosity of approximately $15$ fb$^{-1}$, the process $e^+e^-to 2(p bar{p})$ is studied for the first time. The Born cross sections for $e^+e^-to 2(p bar{p})$ are measured, and no significant structure is observed in the lineshape. The baryon pair ($pp$ and $bar{p}bar{p}$) invariant mass spectra are consistent with phase space, therefore no hexaquark or di-baryon state is found.
The cross section of the process $e^{+} e^{-} rightarrow K^{+} K^{-}$ is measured at a number of center-of-mass energies $sqrt{s}$ from 2.00 to 3.08 GeV with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The results provide the best precision achieved so far. A resonant structure around 2.2 GeV is observed in the cross section line shape. A Breit-Wigner fit yields a mass of $M=2239.2 pm 7.1 pm 11.3$~and a width of $Gamma=139.8pm12.3pm20.6$ MeV, where the first uncertainties are statistical and the second ones are systematic. In addition, the time-like electromagnetic form factor of the kaon is determined at the individual center-of-mass energy points.
M. Ablikim
,M. N. Achasov
,P. Adlarson
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(2021)
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"Study of the process $e^{+}e^{-}rightarrowphieta$ at center-of-mass energies between 2.00 and 3.08 GeV"
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Lei Xia
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