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تسجيل مستخدم جديدDispersive evaluation of the D-term form factor in deeply virtual Compton scattering
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B. Pasquini
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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 $gamma^*gammarightarrow pipi$ subprocess and reconstructing the $pipirightarrow Nbar N$ 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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