Determination of diffractive parton densities at the LHeC and the FCC-eh

Apr 10, 2019, 4:35 PM
20m
Cavallerizza Reale - Aula Magna

Cavallerizza Reale - Aula Magna

Via Verdi, 9 Turin
Parallel Session Talk WG7: Future of DIS Joint WG2+WG7: Small-x and Diff + Future of DIS

Speaker

Anna Stasto (Penn State)

Description

The Large Hadron-electron Collider (LHeC) is a proposed upgrade of the LHC at CERN. An ERL will provide electrons to collide with the HL-LHC, HE-LHC and the FCC-hh proton and ion beams to achieve per nucleon centre-of-mass energies 1.3-3.5 (0.8-2.2) TeV and luminosities $\sim 10^{34(33)}$ cm$^{-2}$s$^{-1}$. These three configurations will enlarge the kinematic plane by more than one order of magnitude towards smaller $x$ and larger $Q^2$ than HERA, which translates into a range of available momentum fraction of the diffractive exchange with respect to the hadron down to $10^{−4} - 10^{−5}$ for a wide range of the momentum fraction of the parton with respect to the diffractive exchange. Here we show the large possibilities that they offer for the determination of diffractive parton densities DPDFs in proton and nuclei. Using the same framework and methodology previously employed at HERA and under very conservative assumptions for the luminosities and systematic errors, we find an improvement in the extraction of DPDFs from fits to reduced cross sections for inclusive coherent diffraction in $ep$ by about an order of magnitude. We analyse the sensitivity to kinematic cuts and variations of the fit framework. We also note sensitivity to the shape of the gluon distribution, and to physics beyond linear twist-2 DGLAP evolution at moderate $Q^2$. For $e$A, we find that an extraction of the currently unmeasured nuclear DPDFs is possible with similar accuracy to that in $ep$.

Primary author

Anna Stasto (Penn State)

Presentation materials