اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدObservation of $e^+e^- to gamma chi_{c1}$ and search for $e^+e^- to gamma chi_{c0}, gamma chi_{c2},$ and $gammaeta_c$ at $sqrt{s}$ near 10.6 GeV at Belle
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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 exclusive 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.
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For the first time we search for the $eta_{c2}(1D)$ in $e^+e^-togammaeta_{c2}(1D)$ at $sqrt{s}$ = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb$^{-1}$, 711 fb$^{-1}$, and 121.4 fb$^{-1}$, respectively, accumulated with the Belle detector
at the KEKB asymmetric energy electron-positron collider. No significant $eta_{c2}(1D)$ signal is observed in the mass range between 3.8 and 3.88 GeV/$c^2$. The upper limit at 90% confidence level on the product of the Born cross section for $e^+e^- to gammaeta_{c2}(1D)$ and branching fraction for $eta_{c2}(1D)to gamma h_c(1P)$ is determined to be $sigma(e^+e^- to gammaeta_{c2}(1D)){cal B}(eta_{c2}(1D)to gamma h_c(1P))$ $<$ 4.9 fb at $sqrt{s}$ near 10.6 GeV.
Based on data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies $sqrt{s} >$ 4.4 GeV, the processes $e^+e^- rightarrow omega chi_{c1,2}$ are observed for the first time. With an integrated lumin
osity of $1074 pb^{-1}$ near $sqrt{s} =$ 4.42 GeV, a significant $omega chi_{c2}$ signal is found, and the cross section is measured to be $(20.9 pm 3.2 pm 2.5)pb$. With $567 pb^{-1}$ near $sqrt{s} =$ 4.6 GeV, a clear $omega chi_{c1}$ signal is seen, and the cross section is measured to be $(9.5 pm 2.1 pm 1.3) pb$, while evidence is found for an $omega chi_{c2}$ signal. The first errors are statistical and the second are systematic. Due to low luminosity or low cross section at other energies, no significant signals are observed. In the $omega chi_{c2}$ cross section, an enhancement is seen around $sqrt{s} =$ 4.42 GeV. Fitting the cross section with a coherent sum of the $psi(4415)$ Breit-Wigner function and a phase space term, the branching fraction $mathcal{B}(psi(4415)toomegachi_{c2})$ is obtained to be of the order of $10^{-3}$.
Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of $sqrt{s}=4.600$ GeV, we search for the production of $e^{+}e^{-} to phichi_{c0,1,2}$ and the charmonium-like state $Y(4140)$ in
the radiative transition $e^{+}e^{-} to gamma Y(4140)$ with $Y(4140)$ subsequently decaying into $phi J/psi$. The processes $e^{+}e^{-} to phichi_{c1}$ and $phichi_{c2}$ are observed for the first time, each with a statistical significance of more than 10sigma, and the Born cross sections are measured to be $(4.2^{+1.7}_{-1.0}pm 0.3)$ pb and $(6.7^{+3.4}_{-1.7}pm 0.5)$ pb, respectively, where the first uncertainties are statistical and the second systematic. No significant signals are observed for $e^{+}e^{-} to phichi_{c0}$ and $e^{+}e^{-} to gamma Y(4140)$ and upper limits on the Born cross sections at $90%$ confidence level are provided at $sqrt{s}=4.600$ GeV.
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.
The $e^+e^- to pi^+ pi^- pi^0 chi_{bJ}$ ($J=0,~1,~2$) processes are studied using a 118~fb$^{-1}$ data sample collected at a center-of-mass energy of 10.867 GeV, in the $Upsilon(10860)$ energy range, with the Belle detector. The $pi^+ pi^- pi^0 chi_{
b1}$, $pi^+pi^-pi^0chi_{b2}$, $omegachi_{b1}$ signals and the evidence of $omegachi_{b2}$ are observed for the first time and the cross sections are measured. No significant $pi^+pi^-pi^0chi_{b0}$ or $omegachi_{b0}$ signal is observed and 90% confidence level upper limits on the cross sections for these two processes are obtained. In the $pi^+pi^-pi^0$ invariant mass spectrum, significant non-$omega$ signals are also observed. We search for the $X(3872)$-like state with a hidden $bbar{b}$ component (named $X_b$) decaying into $omega Upsilon(1S)$; no significant signal is observed with a mass between $10.55$ and $10.65$ GeV/$c^2$.
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