Radiative decays of X (3872 ) discriminate between the molecular and compact interpretations
Abstract
Radiative decays X →ψ (1 S )γ and X →ψ'(2 S )γ might be expected to have a ratio of branching fractions following the phase space volumes ratio. However data suggest the opposite, indicating a value for R =B (ψ'γ )/B (ψ γ ) consistently larger than one. In this paper we present a calculation of R for both a compact diquark-antidiquark (c q )(c ¯q ¯) state and a D D¯ * molecule. In the former case R ∼1 or larger is found. In contrast, in the molecular picture, with D and D¯* mesons described by the universal wave function used by Voloshin, Braaten and Kusunoki, we find R to be of order 10-2. These starkly different predictions are to be confronted with forthcoming high-statistics data analyses; a more precise experimental measure would be extremely helpful in clarifying the true nature of the X (3872 ).
- Publication:
-
Physical Review D
- Pub Date:
- April 2024
- DOI:
- 10.1103/PhysRevD.109.074009
- arXiv:
- arXiv:2401.11623
- Bibcode:
- 2024PhRvD.109g4009G
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 12 pages, 9 figures