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We study the exclusive decay of $J/Psi$ into a lepton pair combined with light hadrons in the kinematic region, specified by that the total energy of the light hadrons is much smaller than $m_c$, the mass of the $c$-quark. In this region, the nonperturbaive effect related to $J/Psi$ and that related to the light hadrons can be separated, the former is represented by a NRQCD matrix element, while the later is represented by a matrix element of a correlator of electric chromofields. The results are obtained in a axial gauge by assumming that contributions from two-gluon emmssion are dominant. But we can show that these results can be obtained without the assumption in arbitrary gauges. A discussion of the results are presented.
We present new calculations of the differential decay rates for $Hto ell^+ell^- gamma$ with $ell=e$ or $mu$ in the Standard Model. The branching fractions and forward-backward asymmetries, defined in terms of the flight direction of the photon relati
The cross section for e^+e^- to eta J/psi between sqrt{s}=3.8 GeV/c^2 and 5.3 GeV/c^2 is measured via initial state radiation using 980 fb^{-1} of data on and around the Upsilon(nS)(n=1,2,3,4,5) resonances collected with the Belle detector at KEKB. T
The abundant production of lepton pairs via $J/Psi$ creation at COMPASS, $pi ^pm , p^uparrow to J/Psi , X to ell^+ ell^- X$, allows a measurement of the transverse Single Spin Asymmetry generated by the Sivers effect. The crucial issue of the sign ch
The process $H to J/psi + gamma$, where $H$ is the Higgs particle, provides a way to probe the size and the sign of the Higgs-charm coupling. In order to improve the theoretical control of the decay rate, we compute order $v^4$ corrections to the dec
We calculate the leading-order perturbative contribution to $gamma p to M_{V} p$, with $M_V$ being a $Phi$ or $J/Psi$ meson, in the kinematic region of large energy and scattering angle.