Derived Born cross sections of e^+e^-annihilation into open charm mesons from CLEO-c measurements

The exclusive Born cross sections of the production of D0, D＋ and Ds＋ mesons in e＋e- annihilation at 13 energy points between 3.970 and 4.260 GeV are obtained by applying corrections for initial state radiation and vacuum polarization to the observed cross sections measured by the CLEO-c experiment. Both the statistical and the systematic uncertainties for the obtained Born cross sections are estimated.

Evidence for further charmonium vector resonances

We discuss the shape of threshold signals in production cross sections of the reaction e＋e- → D＊ Dˉ＊, at the opening of the Ds＊ Dˉs＊ and Λc＋ Λ＋c channels. Furthermore, evidence for the ψ（3D）, ψ（5S）, ψ（4D）, ψ（6S）, ψ（5D）, ψ（7S）, ψ（6D）, and ψ（8S） new charmonium vector resonances is presented, on the basis of data recently published by the BABAR Collaboration. Central masses and resonance widths are estimated. Confirmation of these resonances would be a huge step in lifting the precision level of hadron spectroscopy towards that of atomic spectroscopy, with far-reaching consequences for theory.

Electromagnetic form factors of neutron and neutral hyperons in the oscillating point of view

Based on the recent precise measurements by the BESIII collaboration for electron–positron annihilation into a neutron and antineutron pair,the effective form factors of the neutron were determined in the time-like region,and it was found that the effective form factors of the neutron are smaller than those of the proton.The effective form factors of the neutron show a periodic behaviour,similar to those of the proton.Here,a comparative analysis forΛ,∑^(0)and■hyperons is performed.Fits of the available data on the effective form factors ofΛ,∑^(0)and■with zero charge show an interesting phenomenon in the oscillating behavior of their effective form factors.However,this will need to be confirmed by future precise experiments.Both theoretical and experimental investigations of this phenomenon can shed light on the reaction mechanisms of the electron–positron annihilation processes.

Evidence for e^+e^-→γχ_(c1,2) at center-of-mass energies from 4.009 to 4.360 GeV

Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 GeV with the BES0 detector operating at the BEPC/ collider, we perform a search for the process e＋e-→γχc,j （J =0, 1, 2） and find evidence for e＋e-→γχc1 and e＋e-→γχc2 with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σB（e＋e-→γχc,j）, as well as their upper limits at the 90% con dence level （C.L.） are determined at each center-of-mass energy.

Status of KLOE-2

In a few months the KLOE-2 detector is expected to start data taking at the upgraded DAФNE φ-factory of INFN Laboratori Nazionali di Frascati. It aims to collect 25 fb^-1 at the φ（1020） peak, and about 5 fb^-1 in the energy region between 1 and 2.5 GeV. We review the status and physics program of the project.