Speaker
Mr
Ilkka Helenius
(Lund University)
Description
The current nuclear PDF analyses are mainly constrained by fixed-target
DY and DIS data which provide direct constraints primarily for quarks at
$x > 0.001$. Some constraints for gluons are provided by the inclusive
pion production data in d+Au collisions at RHIC but due to the limited
kinematic reach of the data the small-$x$ nuclear gluon PDFs remain
practically unconstrained in the current fits. In this talk I will
discuss how the existing data from p+Pb collisions at the LHC can improve
the nPDF fits and which measurements would further improve the kinematical
coverage. In particular, I will quantify the $x$ regions probed by inclusive
hadron production at different rapidities and compare this to corresponding
distributions for prompt photon production. Our results indicate that
the prompt photons are more sensitive to the small-$x$ region than the
inclusive hadrons and that the sensitivity can be further increased by
imposing an isolation cut for the prompt photons. Also EPS09-based NLO
predictions for the isolated photon nuclear modification ratio and
forward-to-backward asymmetry are presented.
Primary author
Mr
Ilkka Helenius
(Lund University)
Co-authors
Hannu Paukkunen
(University of Jyväskylä)
Kari J. Eskola
(University of Jyvaskyla)
