اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of $e^+e^-togamma chi_{c0,c1,c2}$ cross sections at center-of-mass energies between 3.77 and 4.60~GeV
168
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The $e^+e^-togammachi_{cJ}$ ($J=0,1,2$) processes are studied at center-of-mass energies ranging from 3.773 to 4.600~GeV, using a total integrated luminosity of 19.3~fb$^{-1}$ $e^+e^-$ annihilation data accumulated with the BESIII detector at BEPCII. We observe for the first time $e^+e^-togamma chi_{c1,c2}$ signals at $sqrt{s}=$ 4.180~GeV with statistical significances of 7.6$sigma$ and 6.0$sigma$, respectively. The production cross section of $e^+e^-togamma chi_{c1,c2}$ at each center-of-mass energy is also measured. We find that the line shape of the $e^+e^-togamma chi_{c1}$ cross section can be described with conventional charmonium states $psi(3686)$, $psi(3770)$, $psi(4040)$, $psi(4160)$. Compared with this, for the $e^+e^-togamma chi_{c2}$ channel, one more additional resonance is added to describe the cross section line shape. Its mass and width are measured to be $M=4371.7pm7.5pm1.8$~MeV/$c^2$ and $Gamma^{tot}=51.1pm17.6pm1.9$~MeV, where the first uncertainties are statistical and the second systematic. The significance of this resonance is estimated to be 5.8$sigma$, and its parameters agree with the $Y(4360)$ resonance previously reported in $e^+e^-topi^+pi^-psi(3686)$, and the $Y(4390)$ in $e^+e^-topi^+pi^-h_c$ within uncertainties. No significant signal for the $e^+e^-togamma chi_{c0}$ process is observed, and the upper limits of Born cross sections $sigma_{B}(e^+e^-togamma chi_{c0})$ at 90% confidence level are reported.
قيم البحث
اقرأ أيضاً
The cross section for the process $e^+e^-to pi^+pi^-J/psi$ is measured precisely at center-of-mass energies from 3.77 to 4.60~GeV using 9~fb$^{-1}$ of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structur
es are observed in a fit to the cross section. The first resonance has a mass of $(4222.0pm 3.1pm 1.4)$~MeV/$c^2$ and a width of $(44.1pm 4.3pm 2.0)$~MeV, while the second one has a mass of $(4320.0pm 10.4 pm 7.0)$~MeV/$c^2$ and a width of $(101.4^{+25.3}_{-19.7}pm 10.2)$~MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the $Y(4260)$ resonance reported by previous experiments. The precision of its resonant parameters is improved significantly. The second resonance is observed in $e^+e^-to pi^+pi^-J/psi$ for the first time. The statistical significance of this resonance is estimated to be larger than $7.6sigma$. The mass and width of the second resonance agree with the $Y(4360)$ resonance reported by the $BABAR$ and Belle experiments within errors. Finally, the $Y(4008)$ resonance previously observed by the Belle experiment is not confirmed in the description of the BESIII data.
Using data samples of 89.5~fb$^{-1}$, 711.0~fb$^{-1}$, and 121.4~fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.867 GeV, respectively, we study the e
xclusive reactions $e^+e^-togammachi_{cJ}$ ($J = 0,~1,~2$) and $e^+e^-togammaeta_c$. A significant $gamma chi_{c1}$ signal is observed for the first time at $sqrt{s}=10.58$ GeV with a significance of $5.1sigma$ including systematic uncertainties. No significant excesses for $gamma chi_{c0}$, $gamma chi_{c2}$, and $gamma eta_c$ final states are found, and we set 90% credibility level upper limits on the Born cross sections ($sigma_{rm B}$) at 10.52 GeV, 10.58 GeV, and 10.867~GeV. Together with cross sections measured by BESIII at lower center-of-mass energies, the energy dependency of $sigma_{rm B}(e^+e^-togammachi_{c1})$ is obtained.
We present first evidence for the process $e^+e^-to gammaeta_c(1S)$ at six center-of-mass energies between 4.01 and 4.60~GeV using data collected by the BESIII experiment operating at BEPCII. These data sets correspond to a total integrated luminosit
y of 4.6~fb$^{-1}$. We measure the Born cross section at each energy using a combination of twelve $eta_c(1S)$ decay channels. Because the significance of the signal is marginal at each energy ($le3.0sigma$), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If the process is assumed to proceed via the $Y(4260)$, we measure a peak Born cross section $sigma_{mathrm{ peak}}(e^+e^-togammaeta_c(1S)) = 2.11 pm 0.49 (mathrm{stat.}) pm 0.36 (mathrm{syst.})$~pb with a statistical significance of 4.2$sigma$.
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 ope
rating 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.
Using the CLEO-c detector at the Cornell Electron Storage Ring, we have measured inclusive and exclusive cross sections for the production of D+, D0 and Ds+ mesons in e+e- annihilations at thirteen center-of-mass energies between 3.97 and 4.26 GeV. E
xclusive cross sections are presented for final states consisting of two charm mesons (DD, D*D, D*D*, Ds+Ds-, Ds*+Ds-, and Ds*+Ds*-) and for processes in which the charm-meson pair is accompanied by a pion. No enhancement in any final state is observed at the energy of the Y(4260).
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
