Measurement of angular correlations inside jets induced by gluon polarization in proton-proton collisions at $ \sqrt{s} = $ 13.6 TeV

A study of angular correlations inside jets induced by gluon polarization is performed using proton-proton collisions at a center-of-mass energy of $ \sqrt{s}= $ 13.6 TeV. The data correspond to an integrated luminosity of 34.7 fb$ ^{-1} $, collected in 2022 with the CMS detector at the LHC. The details of the parton shower are investigated using jets reconstructed with the anti-$ k_{\mathrm{T}} $ algorithm and subsequently declustered with the Cambridge-Aachen algorithm. A novel analysis technique is developed to identify characteristic features of the jet substructure and to select intermediate gluon splittings into quark-antiquark pairs. An observable sensitive to gluon polarization in the parton shower is measured and compared with PYTHIA 8 and HERWIG 7 model predictions, with and without angular correlations induced by the gluon spin. The results are consistent with models that incorporate gluon polarization and strongly disfavor those that neglect them.