Conveners
Parallel 4: high pt in small systems
- Andreas Morsch (CERN)
Measurements at the LHC have provided evidence for collective behavior in high-multiplicity proton-lead (pPb) collisions through multiparticle correlation techniques. Yet, no conclusive evidence of jet quenching, indicating the energy loss of high-$p_\mathrm{T}$ partons as they traverse the medium, has been detected in pPb. This raises the intriguing question: How can a medium described by...
This talk presents two recent ATLAS measurements of multi-particle correlations in pp collisions. The first investigates the relationship between the pp “ridge” and hard scattering processes. In particular, it is not known whether jets or their soft fragments are correlated with particles in the underlying event. To study this “soft-hard” correlation, measurements of two-particle correlations...
Experiments at RHIC and LHC have found no observable evidence of jet quenching in small systems, with one exception — a recent measurement by PHENIX [2303.12899], which compared the yield of neutral pion and direct photon production in very central d+Au collisions. The argument is that the photon yields can be used to correct out any centrality bias effects, and thus the surprisingly strong...
In high-energy collider physics, one of the most important questions is whether quark-gluon plasma (QGP) is formed in pp collisions. Recently, flow-like behaviours have been found in high-multiplicity pp collisions implying collectivity. Stronger evidence for the QGP formation in pp collisions would be signatures of jet quenching, which has not yet been observed. In this contribution, the...
High-multiplicity pp collisions at LHC energies have revealed that small systems can exhibit QGP-like features, suggesting that light-flavor hadron production arises from complex mechanisms whose relative contributions evolve smoothly from low to high multiplicity collisions. Several analyses have recently been performed with event shape classifiers to separate soft and hard components, namely...
The JETSCAPE Collaboration presents a new, multi-observable study of jet transport in the QGP using Bayesian Inference, for the first time incorporating all available inclusive hadron and jet suppression data, and jet substructure data. The theoretical description of jet quenching is multi-stage, based on the MATTER and LBT models, with virtuality-dependent jet-medium interaction. Detailed...
