The ALICE Collaboration reports measurements of the semi-inclusive distribution of charged-particle jets recoiling from a high transverse momentum (high
pT) charged hadron, in
pp and central Pb-Pb collisions at center-of-mass energy per nucleon–nucleon collision
sNN=5.02 TeV. The large uncorrelated background in central Pb-Pb collisions is corrected using a data-driven statistical approach which enables precise measurement of recoil jet distributions over a broad range in
pT,chjet and jet resolution parameter
R. Recoil jet yields are reported for
R=0.2, 0.4, and 0.5 in the range
7<pT,chjet<140 GeV/c and
π/2<Δφ<π, where
Δφ is the azimuthal angular separation between hadron trigger and recoil jet. The low-
pT,chjet reach of the measurement explores unique phase space for studying jet quenching, the interaction of jets with the quark–gluon plasma generated in high-energy nuclear collisions. Comparison of
pT,chjet distributions from
pp and central Pb-Pb collisions probes medium-induced jet energy loss and intra-jet broadening, while comparison of their acoplanarity distributions explores in-medium jet scattering and medium response. The measurements are compared to theoretical calculations incorporating jet quenching. ©2024 CERN, for the ALICE Collaboration 2024 CERN