Electron-Muon Correlations in Proton+Proton and Deuteron+Gold Collisions at PHENIX

This dissertation presents the first measurement of electron-muon azimuthal correlations at the PHENIX experiment at RHIC in 200 GeV proton-proton and deuteron-gold collisions. Electron-muon pairs result from the semileptonic decay of D mesons, which come from correlated charm pairs. The pairs are measured at forward rapidity, with ∣η∣ < 0.5 for the electron and 1.4 < ∣η∣ < 2.1 for the muon. Electron-muon pairs exhibit a characteristic peak at Δφ = π in the azimuthal distribution due to momentum conservation in the 𝑐𝑐¯ decay, and this enables clear identification. The shape of the azimuthal pair distribution in 𝑝+𝑝 collisions helps us determine which hard scattering processes contribute to charm production, and it allows us to test NLO QCD predictions. The 𝑝+𝑝result also serves as a baseline measurement for understanding heavy ion collisions. Pairs were also measured in 𝑑+Au collisions at forward rapidity in the deuteron-going direction, which is a kinematic region at which we expect suppression effects to be evident. The pair yield in 𝑑+Au was found to be suppressed relative to that in 𝑝+𝑝. Also the peak in Δφ almost disappears in 𝑑+Au, indicating either a change in charm production mechanisms or interactions with the nuclear matter.

Author dc:creator

• Engelmore, Tatia

• Nuclear physics
• Proton-proton interactions
• Deuteron reactions
• Gold
• Collisions (Nuclear physics)

Language dc:language

English

DOI dc:identifier

https://doi.org/10.7916/D8V41262

OAI identifier oai:identifier

oai:academiccommons.columbia.edu:10.7916/D8V41262