Pion production in relativistic nucleus–nucleus collisions

Abstract

An experimental study on the production of pions is reviewed, covering pion spectra and multiplicity distributions. Emphasis is placed on progress in characterizing the conditions of nuclear matter by employing particle production observables. Further, the information derived from the Hagedorn temperature of the system emitting pions is critically examined, along with a discussion of the sources responsible for pion emission in the reaction, as revealed by particle spectra and yields.

Multisource Evidence for Final State Hadrons in 3.7A GeV 16O–Nucleus Interactions

“…At AProj ≥ 6, they begin to saturate and have a constant value of < ns b > ~ 0.4 [17]. The results show also that the energy is not an effective parameter in this backward production [17]. Therefore, one can conclude that the backward emitted pion does not come from the fireball nuclear matter or hadronic matter.…”

“…The values of < ns b > are found to increase with projectile size for AProj < 6. At AProj ≥ 6, they begin to saturate and have a constant value of < ns b > ~ 0.4 [17]. The results show also that the energy is not an effective parameter in this backward production [17].…”

“…In the same respect the intercepts are 2.00±0.04 and 0.88±0.02. Independently on the projectile size (AProj = 1 to 32) or energy (Elab = 2.1A to 200A GeV), the backward relativistic hadron is produced with probability values of ~ 20 to 30% for interactions with Em target [17]. The values of < ns b > are found to increase with projectile size for AProj < 6.…”

Interactions in nuclear emulsion detector irradiated by a-particle

“…Eq. 7approximates the values of fit parameters, as b and bs b , to be listed in Table (7 In experiment (31), using a wide range of projectile size (AProj = 1 to 32) interacting in nuclear emulsion at Dubna energy, the values of <ns b > are found to increase with projectile size for AProj< 6. At AProj ≥ 6, they began to saturate and had a constant value of <ns b > ~ 0.4.…”

“…(5) by the straight lines. Independently on the projectile size (AProj = 1 to 32) or energy (Elab = 2.1A to 200A GeV), the backward relativistic hadron is produced with probability values of ~ 20 to 30% for interactions with Em target (31) . The theoretical predictions of the FRITIOF model agree with the data, especially at 3.7A GeV.…”