Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p+p collisions at s =510 GeV

Summary, in English

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at s=510 GeV. Correlations of charged hadrons of 0.7<pT<10 GeV/c with π0 mesons of 4<pT<15 GeV/c or isolated direct photons of 7<pT<15 GeV/c are used to study nonperturbative effects generated by initial-state partonic transverse momentum and final-state transverse momentum from fragmentation. The nonperturbative behavior is characterized by measuring the out-of-plane transverse momentum component pout perpendicular to the axis of the trigger particle, which is the high-pT direct photon or π0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pTtrig). The Gaussian widths and root mean square of pout are reported as a function of the interaction hard scale pTtrig to investigate possible transverse-momentum-dependent evolution differences between the π0-h± and direct photon-h± correlations and factorization breaking effects. The widths are found to decrease with pTtrig, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p+p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.

• Author: A Adare; C. Aidala; N. N. Ajitanand; Y. Akiba; R. Akimoto; J J Alexander; M. Alfred; V. Andrieux; K. Aoki; N Apadula; Y Aramaki; H. Asano; E. T. Atomssa; T. C. Awes; Carmen Ayuso; B. Azmoun; V. Babintsev; M Bai; X. Bai; N. S. Bandara; B Bannier; K N Barish; S Bathe; V. Baublis; C. Baumann; S. Baumgart; A Bazilevsky; M. Beaumier; S. Beckman; R Belmont; A Berdnikov; Y. Berdnikov; D Black; D. S. Blau; M. Boer; J S Bok; K Boyle; M L Brooks; J. Bryslawskyj; H Buesching; V. Bumazhnov; Christopher C. Butler; S. Butsyk; S. Campbell; V. Canoa Roman; R. Cervantes; P. Christiansen; A. Oskarsson; D. Silvermyr; E. Stenlund
• Department/s: Particle and nuclear physics
• Publishing year: 2017-04-01
• Language: English
• Publication/Series: Physical Review D - Particles, Fields, Gravitation and Cosmology
• Volume: 95
• Issue: 7
• Links: http://dx.doi.org/10.1103/PhysRevD.95.072002
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 2470-0010