Results for “multiparton correlators”

DOE OSTI2025

Spin Physics at PHENIX

Situated at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, the PHENIX experiment has for almost two decades been at the forefront of investigations into spin structure and dynamics in high-energy nuclear physics. Although decommissioned in 2016, the PHENIX collaboration has released a number of new results over the past several years that continue to inform the field. Recent longitudinal spin measurements uncover the role of gluon and sea quark polarization in the proton. Transverse spin measurements probe the transverse momentum-dependent (TMD) distributions and higher-twist multiparton correlators that are needed to fully explain partonic dynamics in the initial and final state. Additionally, the effects of heavy ions on spin have been studied by comparing transverse spin measurements between p+p and p+A collisions. These recent results and their wider implications are presented.

PHENIX↗

DOE OSTI2018

Azimuthal correlations for inclusive 2-jet, 3-jet, and 4-jet events in pp collisions at $\sqrt{s}= $ 13 TeV

Azimuthal correlations between the two jets with the largest transverse momenta $p_{\mathrm {T}}$ in inclusive 2-, 3-, and 4-jet events are presented for several regions of the leading jet $p_{\mathrm {T}}$ up to 4 $\,\text {Te}\text {V}$ . For 3- and 4-jet scenarios, measurements of the minimum azimuthal angles between any two of the three or four leading $p_{\mathrm {T}}$ jets are also presented. The analysis is based on data from proton–proton collisions collected by the CMS Collaboration at a centre-of-mass energy of 13 $\,\text {Te}\text {V}$ , corresponding to an integrated luminosity of 35.9 $\,\text {fb}^{-1}$ . Calculations based on leading-order matrix elements supplemented with parton showering and hadronization do not fully describe the data, so next-to-leading-order calculations matched with parton shower and hadronization models are needed to better describe the measured distributions. Furthermore, we show that azimuthal jet correlations are sensitive to details of the parton showering, hadronization, and multiparton interactions. A next-to-leading-order calculation matched with parton showers in the MC@NLO method, as implemented in herwig 7, gives a better overall description of the measurements than the powheg method.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗