Physics at the CERN-ISR

Density saturation and the decrease of the normalised width of the multiplicity distribution in high energy pp collisions

“…If overcrowding takes place (η increases rapidly with energy) then k necessarily will change its behaviour and start increasing with energy. The turning point may occur at an energy of the [16]) and E735 (open squares, [18]). The values of the parameters used [see (14) and (15)] are: α = 0.45,n 1 = 2.9 and c = 1.9 GeV 2 fm 2 .…”

“…This parameter k is also a decreasing function of energy in the √ s ≤ 1.8 TeV region. In Figure 4 we have compared experimental data on p T distributions to the mentioned parameterisation, with k given by the multiplicity distribution values at the [16,24]) fitted with the power-law A(1 + bp 2 T ) −k , using, for each energy, the respective value of k obtained from the multiplicity distribution (from Fig. 3), A and b being free parameters.…”

“…By using equations (14) and (15), and experimental information on n( √ s) [16] and on B( √ s) [17], we can in principle construct N s ( √ s) and η( √ s): from η( √ s) we obtain k( √ s), Eq. (12).…”

Clan Structure Analysis and QCD Parton Showers in Multiparticle Dynamics: An Intriguing Dialog Between Theory and Experiment

“…19. In going from ISR and SERPUKHOV up to CERN pp Collider data [16,80],n becomes larger and k parameter smaller as the c.m. energy of the collision becomes larger, as shown in Figure 20, confirming the general trends of NB parameters already observed in the accelerator and in the cosmic ray regions.…”

The Intersecting Storage Rings (ISR): The First Hadron Collider

“…Despite this somewhat critical assessment of the experimental situation, a wealth of significant results were obtained, all of which contributed to shaping our understanding, as documented e.g. in [10].…”