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Factorization for radiative heavy quarkonium decays into scalar Glueball

Ruilin ZhuSubjects: Physics >> Nuclear Physics

We establish the factorization formula for scalar Glueball production through radiative decays of vector states of heavy quarkonia, e.g.?J/ψ,?ψ(2S)?and?Υ(nS), where the Glueball mass is much less than the parent heavy quarkonium mass. The factorization is demonstrated explicitly at one-loop level through the next-to-leading order (NLO) corrections to the hard kernel, the non-relativistic QCD (NRQCD) long-distance matrix element (LDMEs) of the heavy quarkonium, and the light-cone distribution amplitude (LCDA) of scalar Glueball. The factorization provides a comprehensive theoretical approach to investigate Glueball production in the radiative decays of vector states of heavy quarkonia and to determine the physic nature of Glueball. We discuss the scale evolution equation of LCDA for scalar Glueball. In the end, we extract the value of the decay constant of Scalar Glueball from Lattice QCD calculation and analyze the mixing effect among?f0(1370),?f0(1500)?and?f0(1710). |

Exclusive decay of the upsilon into $h_c$, the $X(3940)$ and $X(4160)$

Ruilin ZhuSubjects: Physics >> Nuclear Physics

In this paper, we study double charmonia production in Upsilon peaks, especially, a S-wave charmonium?ηc?and a P-wave charmonium?hc(1P1), or a S-wave charmonium?J/ψ?and the?X(3940)?and?X(4160)?within the nonrelativistic QCD (NRQCD) approach which is a powerful tool to realize the factorization of double charmonia production in electron-positron annihilation. The?JPC=1???state?Υ(nS)?can provide an ideal laboratory for studying the properties of double-heavy quarkonium and also can separate the perturbative and nonperturbative parts due to the large heavy quark mass compared with the typical hadron scale?ΛQCD. Explanation of the?X(3940)?and?X(4160)?as the?31S0?and?41S0?states, respectively, are compatible with the observed upper limits for the branching fractions of?Υ(1S,2S)→J/ψ+X, where?X=X(3940),?X(4160)?by the Belle Collaboration. The branching fractions of?Υ(1S,2S,3S)→ηc+hc(1P1)?are predicted to be around?10?6, which shall be tested in Belle-II experiments. |

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