Speaker
Description
The interactions between jets and the longitudinal-boosted quark-gluon plasma (QGP) lead to softer particles drifting away from the jet core, where high-$p_\mathrm{T}$ particles remain concentrated, resulting in an intra-jet asymmetry. Investigating this asymmetry, particularly at forward rapidities, offers a novel avenue to probe jet-medium dynamics. Using the PbPb and pp data at $\sqrt{s_{{\mathrm{NN}}}} = 5.02$ TeV collected by the CMS detector, the near-side jet peak of two-particle correlation functions have been examined to explore jet modifications and novel boost invariance phenomena in forward rapidity. The peak exhibits substantial broadening along the longitudinal ($\Delta\eta$) axis from peripheral to central PbPb collisions, indicating energy loss by the progenitor parton. A significant rapidity-dependent asymmetry in associated particle yields has been observed for the first time, with a pronounced difference between $\Delta\eta > 0$ and $\Delta\eta < 0$ that increases at forward rapidity and in central PbPb collisions. This finding, particularly evident for high-$p_\mathrm{T}$ particles, points to a potential violation of boost invariance at forward rapidity. Comparisons with different theoretical models will be discussed to understand the influence of jet-medium interactions on jet structure.
