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Register a new userExploring the $e^+e^-to Lambda_c^+Lambda_c^-$ cross sections
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A simultaneous fit is performed to the $e^+e^-to Lambda_c^+Lambda_c^-$ cross section data measured by Belle and BESIII from threshold up to 5.4 GeV. In order to accommodate both the BESIII measurement near threshold and the Belle observation of a resonance $Y(4630)$, we build a composite PDF with a Breit-Wigner resonance and a continuum contribution to model the full cross section line shape of $e^+e^-to Lambda_c^+Lambda_c^-$. The fit gives a mass of $M=[4636.1_{-7.2}^{+9.8} ($stat$)pm 8.0($syst$)]$~MeV/$c^2$, a width of $Gamma_{rm tot}=[34.5_{-16.2}^{+21.0} ($stat$)pm 5.6($syst$)]$~MeV, and $Gamma_{e^+ e^-}mathcal{B}[Y(4630)toLambda_c^+Lambda_c^-]=[18.3_{-6.1}^{+8.8} ($stat$)pm 1.1($syst$)]$~eV/$c^2$ for the resonance. The width of $Y(4630)$ from our study is narrower than the previous Belle fit. The mass and width of $Y(4630)$ also show good agreement with a vector resonance $Y(4626)$ recently observed in $D_s^+D_{s1}(2536)^-$ by Belle.
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We report a measurement of the exclusive e+e- -->Lambda_c+ Lambda_c- cross section as a function of center-of-mass energy near the Lambda_c+ Lambda_c- threshold. A clear peak with a significance of 8.2 sigma is observed in the Lambda_c+ Lambda_c- invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of M=(4634^{+8}_{-7}(stat.)^{+5}_{-8}(sys.))Mev/c2 and Gamma_tot=(92^{+40}_{-24}(stat.)}^{+10}_{-21}(sys.))MeV are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the Upsilon(4S) resonance and nearby continuum with an integrated luminosity of 695/fb at the KEKB asymmetric-energy e+e- collider.
We report on a comparison of two possible $Lambda_c^+$ spin hypotheses, $J=frac{1}{2}$ and $frac{3}{2}$, via the process $e^+e^-toLambda_c^+barLambda_c^-$, using the angular distributions of $Lambda_c^+$ decays into $pK_S^0$, $Lambdapi^+$, $Sigma^0pi^+$, and $Sigma^+pi^0$. The data were recorded at $sqrt s = 4.6$ GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb$^{-1}$. The $Lambda_c^+$ spin is determined to be $J=frac{1}{2}$, with this value favored over the $frac{3}{2}$ hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
The Born cross sections are measured for the first time for the processes $e^+e^-to D_s^{*+}D_{s0}^*(2317)^- +c.c.$ and $e^+e^-to D_s^{*+}D_{s1}(2460)^- +c.c.$ at the center-of-mass energy $sqrt{s}=$ 4.600~GeV, 4.612~GeV, 4.626~GeV, 4.640~GeV, 4.660~GeV, 4.68~GeV, and 4.700~GeV, and for $e^+e^-to D_s^{*+}D_{s1}(2536)^- +c.c.$ at $sqrt{s}=$ 4.660~GeV, 4.680~GeV, and 4.700~GeV, using data samples collected with the BESIII detector at the BEPCII collider. No structures are observed in cross-section distributions for any of the processes.
The processes $e^+e^-to D_s^+ D_{s1}(2460)^- +c.c.$ and $e^+e^-to D_s^{ast +} D_{s1}(2460)^- +c.c.$ are studied for the first time using data samples collected with the BESIII detector at the BEPCII collider. The Born cross sections of $e^+e^-to D_s^+ D_{s1}(2460)^- +c.c.$ at nine center-of-mass energies between 4.467,GeV and 4.600,GeV and those of $e^+e^-to D_s^{ast +} D_{s1}(2460)^- +c.c.$ at ${sqrt s}=$ 4.590,GeV and 4.600,GeV are measured. No obvious charmonium or charmonium-like structure is seen in the measured cross sections.
We report first measurements of e+e- -> D(*)+D(*)- processes far above threshold. The cross-sections for e+e- -> DT*+DL*- and e+e- -> D+D*T- at sqrt{s}=10.58 GeV/c2 are measured to be 0.55 +- 0.03 +- 0.05 pb and 0.62 +- 0.03 +- 0.06 pb, respectively. We set upper limits on the cross-sections for e+e- -> DT*+DT*-, e+e- -> DL*+DL*-, e+e- -> D+D*L- and e+e- -> D+D- processes. The analysis is based on 88.9 fb-1 of data collected by the Belle experiment at the KEKB e+e- asymmetric collider.
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