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arXiv · 1407.5960

Dispersive evaluation of the D-term form factor in deeply virtual Compton scattering

B. Pasquini·M. V. Polyakov·M. Vanderhaeghen
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Abstract

We present a dispersive representation of the D-term form factor for hard exclusive reactions, using unsubtracted $t$-channel dispersion relations. The $t$-channel unitarity relation is saturated with the contribution of two-pion intermediate states, using the two-pion distributions amplitude for the $γ^*γ\rightarrow ππ$ subprocess and reconstructing the $ππ\rightarrow N\bar N$ subprocess from available information on pion-nucleon partial-wave helicity amplitudes. Results for the D-term form factor as function of $t$ as well as at $t=0$ are discussed in comparison with available model predictions and phenomenological parametrizations.

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B. Pasquini, M. V. Polyakov, M. Vanderhaeghen. 2014-10-20. Dispersive evaluation of the D-term form factor in deeply virtual Compton scattering. https://doi.org/10.1016/j.physletb.2014.10.047

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