Feb 5 – 11, 2017
Hyatt Regency Chicago
America/Chicago timezone

Event activity-dependence of jet production in p--Pb collisions at $\sqrt{s_{NN}} =5.02$ TeV measured with semi-inclusive hadron+jet correlations by ALICE

Feb 7, 2017, 8:30 AM
Regency B

Regency B

Oral Jets and High pT Hadrons Parallel Session 1.2: QCD in Small Systems (I)


Filip Krizek (Acad. of Sciences of the Czech Rep. (CZ))


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.

Collaboration ALICE
Preferred Track Jets and High pT Hadrons

Primary author

Filip Krizek (Acad. of Sciences of the Czech Rep. (CZ))

Presentation materials