Speaker
Description
We report measurement of the semi-inclusive distribution of charged-particle jets recoiling from a high transverse momentum ($p_{T}$) hadron trigger, for p--Pb collisions at $\sqrt{s_{NN}} =5.02$ TeV that have been classified by event activity. This coincidence observable is calculable perturbatively in vacuum, and has previously been measured in pp and Pb--Pb collisions at the LHC, providing a new probe to measure quenching. Jets are reconstructed from charged particle tracks using the anti-kT algorithm with low IR cutoff of jet constituents ($p_T^{track}>0.2$ GeV/c). The analysis applies a data-driven statistical approach to correct the complex uncorrelated jet background, including multi-partonic interactions. Recoil jet distributions are reported for $15 < p_{Tjet} <50$ GeV/c, for R=0.2 and 0.4. Events are classified by signal in the ALICE V0A detector, which measures forward multiplicity, and ZNA, which measures the number of neutrons at zero degrees. The semi-inclusive observable corresponds to the ratio of inclusive cross sections, $d\sigma^\mathrm{h_{trig}+jet}/\sigma^\mathrm{h_{trig}}$, and comparison of the recoil jet yield in p--Pb collisions with different event activity therefore does not require knowledge of $T_\mathrm{pPb}$, thereby avoiding the need for geometric modelling. We compare the trigger-normalized recoil jet yield for p--Pb collisions with different event activity to measure the effects of jet quenching in small systems at the LHC.
| Preferred Track | Jets and High pT Hadrons |
|---|---|
| Collaboration | ALICE |
