Colour-octet contributions to exclusive charmonium decays
| Autor: | Peter Kroll, Jan Bolz, Gerhard A. Schuler |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Physics
Nuclear and High Energy Physics Particle physics Octet High Energy Physics::Phenomenology Degrees of freedom (physics and chemistry) FOS: Physical sciences Fock space High Energy Physics - Phenomenology Fock state Pion High Energy Physics - Phenomenology (hep-ph) High Energy Physics::Experiment Wave function Particle Physics - Phenomenology |
| DOI: | 10.48550/arxiv.hep-ph/9610265 |
| Popis: | We investigate the theoretical uncertainties of $P$-wave charmonium decays into two pions, $\chi_{\c J}\rightarrow \pi^+\pi^-$, $\pi^0\pi^0$. Constraining the pion distribution-amplitude from the recent precise data on $F_{\pi\gamma}(Q^2)$, we find an order-of-magnitude discrepancy between data and prediction. The disagreement persists even after inclusion of transverse degrees of freedom and Sudakov suppressions. We propose the colour-octet mechanism as the solution to the puzzle. The colour-octet decay contribution arising from the higher Fock component $|\c \cbar \g >$ of the $\chi_{\c J}$ wave function is actually not power suppressed with respect to the usual colour-singlet decay arising from the dominant $|\c \cbar >$ Fock state. An explicit calculation yields an agreement with the data for a very reasonable value for the single extra non-perturbative parameter. Comment: 12 pages Latex, 3 PS-files of figures, uses macros 'amstex' and 'psfig'; also available by anonymous ftp from ftp://wpts0.physik.uni-wuppertal.de/pub/bolz/pwav/ |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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