Inclusive diffraction for ep and eA at small x with Sartre

• Tobias Toll (IIT Delhi)

I will describe our ongoing work on implementing inclusive diffraction in the Sartre event generator at small x. Sartre is using the colour dipole model (both with and without saturation effects). For inclusive diffraction we need to take two Fock states of the interacting dipole into consideration: the quark-antiquark dipole, and the quark-antiquark-gluon double dipole. The latter is relevant for the limit of small values of beta or large values of Q2, both resulting in a large invariant mass in the diffractive final state. As these cross section calculations are somewhat CPU intense, I will discuss a method of using cross section lookup tables for fast event generation. Currently, we are only considering coherent diffraction, but these methods can be extended to also include incoherent diffraction if needed in the future. For generating a final state, the resulting quark-antiquark, or quark-antiquark-gluon states are fed into Pythia 8 for string fragmentation resulting in a hadronic final state in the event record. Furthermore, we have devised a semiclassical multiple scattering model to take into account azimuthal decorrelations between the final state particles, which could be used as a signal for a saturated state of matter.

Inclusive diffraction at the EIC

• Paul Newman (University of Birmingham, UK)

This talk will discuss the semi-inclusive process, ep -> eXp. Progress from HERA will be briefly reviewed before focusing on prospects for the EIC. After establishing the kinematic range that can be accessed at an experiment such as ePIC, the expected cross sections will be broken down into contributions from the leading pomeron and sub-leading 'Reggeon' colourless exchanges. Prospects for measuring the associated 'diffractive' parton densities will be covered, as will an assessment of sensitivity to the longitudinal diffractive structure function, which offers a new pathway to extracting the diffractive gluon density.