Decays of the X(3872) and theχc1(2P)charmonium state

Abstract

We reexamine the rescattering mechanism for the X(3872), as a candidate for the 2P charmonium state c1 2P, decaying to J= ! through exchanging D mesons between intermediate states D D and D D . We evaluate the dispersive part, as well as the absorptive one, of the rescattering amplitude and find that the contribution from the dispersive part is dominant even when X(3872) lies above the threshold of the neutral channel th n m D 0 m D 0 . We predict R =! ' 1 for the m X region scanned by experiments. Meanwhile, we also estimate the rate of X ! D 0 D 0 0 . Our results favor a charmonium interpretation of X(3872) when it lies slightly below the threshold of D 0 D 0 . Furthermore, we evaluated the width of X ! J= with the help of a phenomenological effective coupling constant g X , and find the total width of X(3872) to be in the range of 1-2 MeV.

Isospin violating decay ofψ(3770)→J/ψ+π0

“…7 and compare it with our QCD-motivated form factors. It is obvious that our form factors favor α > 2, which is consistent with the value used in the study of X(3872) decays [41].…”

The hidden-charm pentaquark and tetraquark states

“…The isospin violating decay process, X(3872) → J/ψρ(→ π + π − ), can happen through final state interactions with the intermediate DD * loop [692]. With this mechanism, the ratio R ρ/ω ≡ Γ(X(3872)→J/ψρ) Γ(X(3872)→J/ψω) 1 [693]. With the screening potential, the ratio of B(X(3872) → ψ γ) to B(X(3872) → J/ψγ) was 1.3 − 6.0 [601], which is consistent with the present experimental data [89,92].…”

Observation of a Resonancelike Structure in theπ+−ψ′Mass Distribution in ExclusiveB→Kπ+−Choi1, Olsen2, Adachi3 et al. 2008Phys. Rev. Lett.50171970View full textAdd to dashboardCite

“…Proposed assignments for these states have included: multiquark states, either of the (cq,cq) "molecular" type [10] or [cq,cq] diquark-antidiquark type [11] (here c represents a charmed quark and q either a u-, d-or s-quark); hybrid cc-gluon mesons [12]; or other missing charmonium states where the masses predicted by potential models are drastically modified by nearby D ( * )D( * ) thresholds [13,14]. A characteristic that clearly distinguishes multiquark states from hybrids or charmonia is the possibility to have charmonium-like mesons with non-zero charge (e.g.…”