Abstract
Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at s=200 GeV. The correlations are sensitive to nonperturbative initial-state and final-state transverse momenta kT and jT in the azimuthal nearly back-to-back region Δφ∼π. To have sensitivity to small transverse momentum scales, nonperturbative momentum widths of pout, the out-of-plane transverse-momentum component perpendicular to the trigger particle, are measured. In this region, the evolution of pout can be studied when several different hard scales are measured. These widths are used to investigate possible effects from transverse-momentum-dependent factorization breaking. When accounting for the longitudinal-momentum fraction of the away-side hadron with respect to the near-side trigger particle, the widths are found to increase with the hard scale; this is qualitatively similar to the observed behavior in Drell-Yan and semi-inclusive deep-inelastic scattering interactions, where factorization is predicted to hold. The momentum widths are also studied as a function of center-of-mass energy by comparing to previous measurements at s=510 GeV. The nonperturbative jet widths also appear to increase with s at a similar xT, which is qualitatively consistent to similar measurements in Drell-Yan interactions. Future detailed global comparisons between measurements of processes where transverse-momentum-dependent factorization is predicted to hold and be broken will provide further insight into the role of color in hadronic interactions.
| Original language | English |
|---|---|
| Article number | 072004 |
| Journal | Physical Review D |
| Volume | 98 |
| Issue number | 7 |
| DOIs | |
| State | Published - Oct 1 2018 |
Funding
We thank the staff of the Collider-Accelerator and Physics Departments at Brookhaven National Laboratory and the staff of the other PHENIX participating institutions for their vital contributions. We also thank J. C. Collins for valuable discussions regarding the interpretation of these results. We acknowledge support from the Office of Nuclear Physics in the Office of Science of the Department of Energy, the National Science Foundation, Abilene Christian University Research Council, Research Foundation of SUNY, and Dean of the College of Arts and Sciences, Vanderbilt University (United States); Ministry of Education, Culture, Sports, Science, and Technology and the Japan Society for the Promotion of Science (Japan); Conselho Nacional de Desenvolvimento Científico e Tecnológico and Fundação de Amparo à Pesquisa do Estado de São Paulo (Brazil); Natural Science Foundation of China (People’s Republic of China); Croatian Science Foundation and Ministry of Science and Education (Croatia); Ministry of Education, Youth and Sports (Czech Republic); Centre National de la Recherche Scientifique, Commissariat à l’Énergie Atomique, and Institut National de Physique Nucléaire et de Physique des Particules (France); Bundesministerium für Bildung und Forschung, Deutscher Akademischer Austausch Dienst, and Alexander von Humboldt Stiftung (Germany); J. Bolyai Research Scholarship, EFOP, the New National Excellence Program (ÚNKP), NKFIH, and OTKA (Hungary); Department of Atomic Energy and Department of Science and Technology (India); Israel Science Foundation (Israel); Basic Science Research Program through NRF of the Ministry of Education (Korea); Physics Department, Lahore University of Management Sciences (Pakistan); Ministry of Education and Science, Russian Academy of Sciences, Federal Agency of Atomic Energy (Russia); VR and Wallenberg Foundation (Sweden); the U.S. Civilian Research and Development Foundation for the Independent States of the Former Soviet Union; the Hungarian American Enterprise Scholarship Fund; the US-Hungarian Fulbright Foundation; and the US-Israel Binational Science Foundation.