From QCD-based hard-scattering to nonextensive statistical mechanical descriptions of transverse momentum spectra in high-energy $pp$ and $p\overline{p}$ collisions

Journal Article · Mon Jun 22 00:00:00 EDT 2015 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI:https://doi.org/10.1103/PhysRevD.91.114027· OSTI ID:1185995

Wong, Cheuk-Yin ^[1]; Wilk, Grzegorz ^[2]; Cirto, Leonardo J. L. ^[3]; Tsallis, Constantino ^[4]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division
2. National Centre for Nuclear Research, Warsaw (Poland)
3. Ministerio da Ciencia, Tecnologia e Inovacao (MCTI), Rio de Janiero (Brazil). Centro Brasileiro de Pesquisas Fisicas (CBPF) & National Inst. of Science and Technology for Complex Systems
4. Ministerio da Ciencia, Tecnologia e Inovacao (MCTI), Rio de Janiero (Brazil). Centro Brasileiro de Pesquisas Fisicas (CBPF) & National Inst. of Science and Technology for Complex Systems; Santa Fe Institute, Santa Fe, NM (United States)

Transverse spectra of both jets and hadrons obtained in high-energy $pp$ and $$p\bar p $$ collisions at central rapidity exhibit power-law behavior of $$1/p_T^n$$ at high $$p_T$$. The power index $$n$$ is 4-5 for jet production and is slightly greater for hadron production. Furthermore, the hadron spectra spanning over 14 orders of magnitude down to the lowest $$p_T$$ region in $pp$ collisions at LHC can be adequately described by a single nonextensive statistical mechanical distribution that is widely used in other branches of science. This suggests indirectly the dominance of the hard-scattering process over essentially the whole $$p_T$$ region at central rapidity in $pp$ collisions at LHC. We show here direct evidences of such a dominance of the hard-scattering process by investigating the power index of UA1 jet spectra over an extended $$p_T$$ region and the two-particle correlation data of the STAR and PHENIX Collaborations in high-energy $pp$ and $$p \bar p$$ collisions at central rapidity. We then study how the showering of the hard-scattering product partons alters the power index of the hadron spectra and leads to a hadron distribution that can be cast into a single-particle non-extensive statistical mechanical distribution. Lastly, because of such a connection, the non-extensive statistical mechanical distribution can be considered as a lowest-order approximation of the hard-scattering of partons followed by the subsequent process of parton showering that turns the jets into hadrons, in high energy $pp$ and $$p\bar p$$ collisions.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1185995
• Alternate ID(s): OSTI ID: 1198503
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 91, Issue 11; ISSN 1550-7998
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English