Pion polarizabilities from a dispersive analysis of γγ → ππ
| Autor: | Ermolina Viktoriia, Danilkin Igor, Vanderhaeghen Marc |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | EPJ Web of Conferences, Vol 303, p 01007 (2024) |
| Druh dokumentu: | article |
| ISSN: | 2100-014X 20243030 |
| DOI: | 10.1051/epjconf/202430301007 |
| Popis: | We present results for the charged and neutral pion polarizabilities, obtained through a dispersive analysis of photon-fusion reactions with two pions in the final state. This analysis is motivated by current and future measurements at COMPASS, JLab (Hall D), and the BESIII measurement of singlevirtual photon-fusion reactions in the space-like region, offering insight into generalized pion polarizabilities. To improve upon predictions within an un-subtracted dispersion formalism with only the pion left-hand cut, one needs to consider the influence of heavier left-hand cuts. We parametrize the latter using an expansion in a suitably constructed conformal variable, capturing the analytical structure of the left-hand cuts. The coefficients in this expansion are determined from the matching with the Lagrangian-based approach, the Adler zero constraint for γγ → π0π0, and a fit to the cross-section data. The extension to the single-virtual case is also discussed. |
| Databáze: | Directory of Open Access Journals |
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