English

Is the $J^P=2^-$ assignment for the $X(3872)$ compatible with the radiative transition data?

High Energy Physics - Phenomenology 2010-08-27 v2 High Energy Physics - Experiment

Abstract

The very recent analysis by BaBar Collaboration indicates that the X(3872)X(3872) may favor the quantum number JPC=2+J^{PC}=2^{-+} rather than the previously assumed 1++1^{++}. By pretending the ηc2(1D)\eta_{c2}(1D) charmonium to be the X(3872)X(3872), we study the parity-even radiative transition processes ηc2(1D)J/ψ(ψ)+γ\eta_{c2}(1D)\to J/\psi(\psi')+\gamma within several phenomenological potential models. We take the 3D1{}^3D_1 admixture in ψ\psi' into account, and consider the contributions from the magnetic dipole (M1M1), electric quadrupole (E2E2), and magnetic octupole (M3M3) amplitudes. It is found that the ratio of the branching fractions of these two channels, as well as the absolute branching fraction of ηc2ψγ\eta_{c2}\to \psi'\gamma, are in stark contradiction with the existing \textsc{BaBar} measurements. This may indicate that the 2+2^{-+} assignment for the X(3872)X(3872) is highly problematic.

Keywords

Cite

@article{arxiv.1007.4541,
  title  = {Is the $J^P=2^-$ assignment for the $X(3872)$ compatible with the radiative transition data?},
  author = {Yu Jia and Wen-Long Sang and Jia Xu},
  journal= {arXiv preprint arXiv:1007.4541},
  year   = {2010}
}

Comments

v2; 14 pages, 3 tables; references, a new table and several footnotes added, text refined; a minus sign added for the definition of J1 in (14b), accordingly Table I and II and equations (21,22,23) are corrected to reflect this change, but the conclusion remains

R2 v1 2026-06-21T15:53:13.259Z