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Volume 346 - 23rd International Spin Physics Symposium (SPIN2018) - Parallel Session: 3D Structure of the Nucleon: GPDs and Form Factors (C. Lorce and S. Niccolai)
The D-term form factor from dispersion relations in deeply virtual Compton scattering
B. Pasquini
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Pre-published on: 2019 August 19
Published on: 2019 August 23
We review a dispersive calculation of the D-term form factor, using unsubtracted $t$-channel dispersion relations for the deeply virtual Compton scattering amplitudes. The $t$-channel unitarity relation is saturated with the contribution of two-pion intermediate states, using the two-pion generalized distributions amplitude for the $\gamma^*\gamma\rightarrow \pi \pi$ subprocess and reconstructing the $\pi\pi\rightarrow N\bar{N}$ subprocess from available information on pion-nucleon partial-wave helicity amplitudes. The dispersion-relation results are discussed in comparison with available model predictions and phenomenological extractions.
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