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Title: From QCD-based hard-scattering to nonextensive statistical mechanical descriptions of transverse momentum spectra in high-energy pp and pp¯ collisions

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.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  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)
Publication Date:
OSTI Identifier:
1185995
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 91; Journal Issue: 11; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS