Novel physical phenomena can emerge in low-dimensional nanomaterials. Bulk MoS(2), a prototypical metal dichalcogenide, is an indirect bandgap semiconductor with negligible photoluminescence. When the MoS(2) crystal is thinned to monolayer, however, a strong photoluminescence emerges, indicating an indirect to direct bandgap transition in this d-electron system. This observation shows that quantum confinement in layered d-electron materials like MoS(2) provides new opportunities for engineering the electronic structure of matter at the nanoscale.

The Ξ_{c}^{+}K^{-} mass spectrum is studied with a sample of pp collision data corresponding to an integrated luminosity of 3.3  fb^{-1}, collected by the LHCb experiment. The Ξ_{c}^{+} is reconstructed in the decay mode pK^{-}π^{+}. Five new, narrow excited Ω_{c}^{0} states are observed: the Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3066)^{0}, Ω_{c}(3090)^{0}, and Ω_{c}(3119)^{0}. Measurements of their masses and widths are reported.

At present the color-octet mechanism is still an important and debatable part in the nonrelativistic QCD(NRQCD). We find in this work that the polarized double charmonium production at the LHC may pose a stringent test on the charmonium production mechanism. Result shows that the transverse momentum(p T ) scaling behaviors of double J/ψ differential cross sections in color-singlet and -octet production mechanisms deviate distinctively from each other while p T is larger than 7 GeV. In color-octet mechanism, the two J/ψs in one pair are mostly transversely polarized when p T ≫ 2m c , as expected from the fragmentation limit point of view. In color-singlet mechanism, there is about one half of the charmonium pairs with at least one J/ψ being longitudinally polarized at moderate transverse momentum. The energy dependence of the polarized J/ψ pair production is found to be weak, and this process is found to be experimentally attainable in the early phase of the LHC operation.

The Born cross section for the process e þ e − → pp is measured using the initial state radiation technique with an undetected photon. This analysis is based on datasets corresponding to an integrated luminosity of 7.5 fb −1 , collected with the BESIII detector at the BEPCII collider at center of mass energies between 3.773 and 4.600 GeV. The Born cross section for the process e þ e − → pp and the proton effective form factor are determined in the pp invariant mass range between 2.0 and 3.8 GeV=c 2 divided into 30 intervals. The proton form factor ratio (jG E j=jG M j) is measured in 3 intervals of the pp invariant mass between 2.0 and 3.0 GeV=c 2 .

The process e + e − → ppγ is studied using 469 fb −1 of integrated luminosity collected with the BABAR detector at the SLAC National Accelerator Laboratory, at an e + e − center-of-mass energy of 10.6 GeV. From the analysis of the pp invariant mass spectrum, the energy dependence of the cross section for e + e − → pp is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |GE/GM |, and the asymmetry in the proton angular distribution are measured for pp masses below 3 GeV. The branching fractions for the decays J/ψ → pp and ψ(2S) → pp are also determined.