Search for jet quenching with high <i>p</i> _T hadron azimuthal anisotropy using subevent cumulants in pPb collisions at CMS

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 — the energy loss of high- p T partons as they traverse the medium — has been detected in pPb. This raises the intriguing question: How can a medium described by hydrodynamics, and that significantly modifies the distribution of final-state hadrons, yet has no significant impact on the distribution of high-pT particles? To investigate this, a comprehensive study of differential Fourier coefficients ( v n ) in particle transverse momentum ( p T ) and event multiplicity is presented in pPb collisions recorded by the CMS experiment at a nucleon-nucleon centerof- mass energy √ s NN = 8.16 TeV. In particular, new measurements of p T -differential multiparticle cumulants using the subevent method probes an extended phase space region up to a high particle p T . Additionally, we compare the results between pPb and PbPb collisions in the same multiplicity window.