P-wave quarkonium decays to meson pairs

Abstract

The processes of p-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in the framework of non-relativistic quantum chromodynamics, whereas for light mesons, the light cone distribution amplitudes up to twist-3 are employed. It turns out that the higher twist contribution is significant and provides a possible explanation for the observation of the hadron helicity selection rule violated processes χ c1 → φφ, ωω by the BESIII collaboration in recently. We also evaluate the χ b1 → J/ψJ/ψ process and find that its branching ratio is big enough to be measured at the B-factories.

Exclusive decay ofΥintoJ/ψ+χc0,1,2

“…The partial widths of the similar decay processes Çð1S; 2S; 3SÞ ! J=c þ 0 cJ , c 0 þ cJ , c 0 þ 0 cJ (J ¼ 0, 1, 2) can also be readily obtained, provided that we substitute the appropriate kinematical factor and the corresponding (first derivative of) wave functions at the origin for c 0 and 0 cJ in (11). Interestingly, the NRQCD formalism seems to imply that Ç !…”

“…These inputs are used to determine jPj according to (4), which appears in the phase space factor in (11). To calculate the squared matrix elements, particularly the functions f J ; ðrÞ and g J ; ðrÞ, we instead adopt the following values for the quark masses: m c ¼ 1:5 GeV, m b ¼ 4:7 GeV, corresponding to r ¼ 0:102.…”

“…J=c ðÞ þ c0;1;2 ðÞ for each independent helicity configurations ð;Þ, together with the polarizationsummed results. To readily visualize the interference effect among three distinct decay mechanisms, we also tabulate the individual decay rates from the single-photon, threegluon, and one-photon-two-gluon channels, respectively, as well as the full decay rate given by (11). Table II reveals that a and a 3g in Çð1SÞ !…”

“…À ½J , À ½J 3g , and À ½J gg represent the individual decay rates from the single-photon, three-gluon, and one-photon-two-gluon channels affiliated with the process Çð1SÞ ! J=c þ cJ (J ¼ 0, 1, 2), respectively, while À ½J tot denotes the decay rate which incorporates all three decay mechanisms according to (11). The two rightmost columns also give the unpolarized decay rates and branching fractions by summing over all possible helicity configurations.…”

Evidence of $Υ(1S) \to J/ψ+χ_{c1}$ and search for double-charmonium production in $Υ(1S)$ and $Υ(2S)$ decays

“…Inspired by the unexpectedly high double-charmonium production in e + e − annihilation, interest has turned to the double-charmonium states produced in bottomonium decays. Several theoretical calculations have focused on these processes in perturbative QCD, e.g., η b → J/ψJ/ψ [22][23][24][25] and χ b0,1,2 → J/ψJ/ψ [26][27][28][29]. Experimentally, however, such studies are extremely sparse, apart from the recent searches for several channels of χ bJ into double charmonia for the first time by the Belle Collaboration [30].…”