Quark Matter 2023

ATLAS measurements of b-jet suppression and heavy-flavor azimuthal correlations in 5.02 TeV Pb+Pb collisions

5 Sept 2023, 09:30

20m

Ballroom F (Hilton of the Americas)

Oral Jets Jets

Speaker

Anne Marie Sickles (Univ. Illinois at Urbana Champaign (US))

Description

The suppression of jets in heavy-ion collisions can provide detailed information about the hot, dense plasma formed in these collisions at the LHC. Jet quenching in heavy-ion collisions is expected to depend on the mass of the fragmenting parton. For light partons, energy loss via gluon bremsstrahlung is expected to dominate, while for heavy-quark-initiated jets, collisional energy loss may play a more important role. This energy loss mechanism can be studied by measuring differences in the suppression of $b$-tagged and inclusive jets in $pp$ and Pb+Pb collisions. Besides the $b$-tagged jet measurements, an alternative method for probing the interactions of heavy quarks with the plasma is the study of the correlations between heavy-quark pairs, which is sensitive to the relative importance of collisional versus radiative scattering processes. In this talk, we report new ATLAS measurements of $b$-tagged and inclusive jet production as well as the measurement of the yield of correlated muon pairs from heavy-flavor decays in Pb+Pb and $pp$ collisions at $\sqrt{s_{\text{NN}}}=5.02$~TeV. For $b$-tagged and inclusive jet, the transverse momentum distributions in Pb+Pb and $pp$ collisions, as well as the nuclear modification factors, $R_{AA}$, in Pb+Pb collisions, are presented together with comparisons to theoretical calculations. The measurement of correlated muon pairs from heavy-flavor decays includes per-event yields, scaled by the nuclear thickness function, $T_{AA}$ will be discussed. Detailed studies of how the shape of the correlation in azimuthal-angle separation between the two muons changes from peripheral to central Pb+Pb collisions and comparison to the corresponding measurements in $pp$ collisions are also presented.

Presentation materials

sickles_090523.pdf