Pion polarizabilities from a analysis
- Institut fur Kernphysik and Julich Center for Hadron Physics, Forschungszentrum Julich, Julich (Germany); Indiana Univ., Bloomington, IN (United States)
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States)
Here, we present results for pion polarizabilities predicted using dispersion relations from our earlier Amplitude Analysis of world data on two photon production of meson pairs. The helicity-zero polarizabilities are rather stable and insensitive to uncertainties in cross-channel exchanges. The need is first to confirm the recent result on $$(\alpha_1-\beta_1)$$ for the charged pion by COMPASS at CERN to an accuracy of 10% by measuring the $$\gamma\gamma\to\pi^+\pi^-$$ cross-section to an uncertainty of ~1\%. Then the same polarizability, but for the $$\pi^0$$, is fixed to be $$(\alpha_1-\beta_1)_{\pi^0}=(0.9\pm0.2)\times 10^{-4}$$ fm$$^{3}$$. By analyzing the correlation between uncertainties in the meson polarizability and those in $$\gamma\gamma$$ cross-sections, we suggest experiments need to measure these cross-sections between $$\sqrt{s}\simeq 350$$ and 600~MeV. The $$\pi^0\pi^0$$ cross-section then makes the $$(\alpha_2-\beta_2)_{\pi^0}$$ the easiest helicity-two polarizability to determine.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SFB/TR 110; AC05-06OR23177
- OSTI ID:
- 1338179
- Alternate ID(s):
- OSTI ID: 1338122
- Report Number(s):
- JLAB-THY-16-2386; DOE/OR/23177-4002; arXiv:1611.14441; PRVDAQ; TRN: US1701067
- Journal Information:
- Physical Review D, Vol. 94, Issue 11; ISSN 2470-0010
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Nature of the : A light-quark perspective
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journal | April 2019 |
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