Friday, April 27, 2012

1112.4615 (Hai-Qing Zhou et al.)

Resonances contribution to two-photon exchange effects and possible
large forward-backward asymmetry in $e^+ e^- \rightarrow p \bar{p}$
   [PDF]

Hai-Qing Zhou, Bing-Song Zou
The resonances ($\eta_c,\chi_{c0,c2}$) contribution to two-photon exchange (TPE) effects in $e^+ e^- \leftrightarrow p \bar{p}$ is calculated in a simple hadronic model. The calculation shows the TPE contributions by resonance $\chi_{c2}$, which are dependent on the unknown phases $\phi_{E,M}$ of proton's time-like form factors $G_{E,M}$, are much larger than the TPE contributions by non-resonance and are comparable with measurement precision of coming PANDA detector at $\sqrt{s} \sim M_{\chi_{c2}}$ for most $\phi_{E,M}$.
View original: http://arxiv.org/abs/1112.4615

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