Probing small-x gluons with gamma+hadron correlations in the forward rapidity with the LHCb detector

4 Nov 2019, 17:40
20m
Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Poster Presentation Electromagnetic probes Poster Session

Speaker

Maitreyee Mukherjee (Central China Normal University CCNU (CN))

Description

Gluon nuclear PDFs still have large uncertainties in the small-x ($x$<10^{-3}) and small virtuality $Q^2<$50 (GeV/c)$^{2}$ region. Yields from particles coming from these gluons obtained in nuclear collisions are suppressed relative to $p$+$p$ collisions because of initial-state effects such as shadowing, energy loss and gluon saturation. Precise measurement of yields coming from small-x, small-$Q^2$ gluons are essential to understand these effects which have a significant contribution to the suppressions observed in A+A collisions at RHIC and LHC. The inverse Compton process $q+q\rightarrow \gamma+q \rightarrow \gamma+h$ is one of the few which can access and provide information on the gluon $x$ and $Q^2$ in the region where nPDFs are not well constrained. The LHCb detector can measure photons through the Electromagnetic Calorimeter or photon conversion to dielectrons in the pseudorapidity range 2$<\eta<$5, covering $x>5\times 10^{-6}$ and $Q^2>2$GeV$^2$ in the case of inverse Compton processes. This unique coverage allow us to search for the gluon saturation scale, the transition between dilute and saturated gluons, predicted by the Color-Glass Condensate effective theory. This presentation will show the status of the isolated $\gamma+$hadron correlation analysis using data collected in $p$+Pb and Pb+$p$ collisions at 8.16 TeV and $p$+$p$ collisions at 8 TeV. New techniques will also be presented to identify isolated photons and subtract the large background from neutral meson decays.

Primary author

Maitreyee Mukherjee (Central China Normal University CCNU (CN))

Presentation Materials