skip to main content


Title: The origin of thermal component in the transverse momentum spectra in high energy hadronic processes

The transverse momentum spectra of hadrons produced in high energy collisions can be decomposed into two components: the exponential ("thermal") and the power ("hard") ones. Recently, the H1 Collaboration has discovered that the relative strength of these two components in Deep Inelastic Scattering (DIS) depends drastically upon the global structure of the event - namely, the exponential component is absent in the diffractive events characterized by a rapidity gap. We discuss the possible origin of this effect and speculate that it is linked to confinement. Specifically, we argue that the thermal component is due to the effective event horizon introduced by the confining string, in analogy to the Hawking-Unruh effect. In diffractive events, the t-channel exchange is color-singlet and there is no fragmenting string - so the thermal component is absent. The slope of the soft component of the hadron spectrum in this picture is determined by the saturation momentum that drives the deceleration in the color field, and thus the Hawking-Unruh temperature. We analyze the data on non-diffractive pp collisions and find that the slope of the thermal component of the hadron spectrum is indeed proportional to the saturation momentum.
 [1] ;  [2] ;  [3]
  1. Moscow Inst. of Physics and Technology (MIPT), Moscow (Russian Federation); Inst. of Theoretical and Experimental Physics (ITEP)
  2. Stony Brook Univ., NY (United States). Dept. of Physics and Astronomy; Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Physics
  3. Russian Academy of Sciences (RAS), Moscow (Russian Federation). Inst. for Information Transmission Problems (IITP)
Publication Date:
Report Number(s):
Journal ID: ISSN 0218-3013; KB0301020; TRN: US1500560
Grant/Contract Number:
Accepted Manuscript
Journal Name:
International Journal of Modern Physics E
Additional Journal Information:
Journal Volume: 23; Journal Issue: 12; Journal ID: ISSN 0218-3013
World Scientific
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; multiparticle production; hadron collisions; Unruh effect
OSTI Identifier: