The VII-th International Conference on the Initial Stages of High-Energy Nuclear Collisions : Initial Stages 2023

Multiparticle correlations of soft and hard probes in small systems with the CMS experiment

Not scheduled

2h

Københavns Universitetsbibliotek Nord

Poster Collective dynamics from small to large systems Reception and poster session

Speaker

Rohit Kumar Singh (Indian Institute of Technology Madras (IN))

Description

Measurements by CMS have provided evidence for the collective behavior of multiparticle production in high-multiplicity proton-proton (pp) and proton-lead (pPb) collisions at the LHC. Although this collectivity aligns with the notion of a hydrodynamic flow origin, it is also possible to interpret it in relation to initial-state correlations caused by, for example, gluon saturation. To investigate detailed properties of this collectivity, a comprehensive study of differential Fourier coefficients ($v_n$) in particle transverse momentum ($p_\mathrm{T}$) and event multiplicity are presented. In particular, new measurements of $p_\mathrm{T}$-differential multiparticle cumulants using the subevent higher order particle cumulant method in distinct subevent regions are presented. Relative to past CMS measurements, the new study probes an extended phase space region up to particle $p_\mathrm{T} \sim 20$ GeV, where results will shed light on possible evidence for energy loss of high-$p_\mathrm{T}$ partons in a small-sized medium. In addition, correlations between multiparticle cumulants and the mean $p_{\mathrm{T}}$ in pp, pPb, and peripheral lead-lead collisions of different energies are presented as a function of charged-particle multiplicity. Predictions based on color-glass condensate and hydrodynamic models are compared to the experimental results.