scholarly journals Proton–proton, pion–proton and pion–pion diffractive collisions at ultrahigh energies

2014 ◽  
Vol 29 (15) ◽  
pp. 1450096 ◽  
Author(s):  
V. V. Anisovich ◽  
K. V. Nikonov ◽  
V. A. Nikonov ◽  
J. Nyiri

The LHC energies are those at which the asymptotic regime in hadron–hadron diffractive collisions (pp, πp, ππ) might be switched on. Based on results of the Dakhno–Nikonov eikonal model which is a generalization of the Good–Walker eikonal approach for a continuous set of channels, we present a picture for transformation of the constituent quark mode to the black disk one. In the black disk mode [Formula: see text], we have a growth of the logarithm squared type for total and elastic cross-sections, σ tot ~ ln 2 s and σ el ~ ln 2 s and [Formula: see text]-scaling for diffractive scattering and diffractive dissociation of hadrons. The diffractive dissociation cross-section grows as σD ~ ln s, σDD ~ ln s, and their relative contribution tends to zero: σD/σ tot → 0, σDD/σ tot → 0. Asymptotic characteristics of diffractive and total cross-sections are universal, and this results in the asymptotical equality of cross-sections for all types of hadrons (the Gribov universality). The energy scale for switching on the asymptotic mode is estimated for different processes.

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 24
Author(s):  
Sebastian Scheid

The ALICE Collaboration measured dielectron production as a function of the invariant mass ( m ee ), the pair transverse momentum ( p T , ee ) and the pair distance of closest approach ( DCA ee ) in pp collisions at s = 7 TeV. Prompt and non-prompt dielectron sources can be separated with the DCA ee , which will give the opportunity in heavy-ion collisions to identify thermal radiation from the medium in the intermediate-mass range dominated by contributions from open-charm and beauty hadron decays. The charm and beauty total cross sections are extracted from the data by fitting the spectra with two different MC generators, i.e., PYTHIA a leading order event generator and POWHEG a next-to-leading order event generator. Significant model dependences are observed, reflecting the sensitivity of this measurement to the heavy-flavour production mechanisms.


2015 ◽  
Vol 30 (08) ◽  
pp. 1542006 ◽  
Author(s):  
Claude Bourrely ◽  
Jacques Soffer ◽  
Tai Tsun Wu

In 1970, on purely theoretical grounds, all total hadronic total cross-sections were predicted to increase without limit for higher and higher energies. This was contrary to the conventional belief at that time. In 1978, an accurate phenomenological model was formulated for the case of proton–proton and antiproton-proton interactions. The parameters for this model were slightly improved in 1984 using the additional available experimental data. Since then, for 30 years these parameters have not changed. This development, including especially the difficult task of formulating this phenomenological model and the comparison of the predictions of this model with later experimental results, is summarized.


The main features of the C. E. R. N. Intersecting Storage Rings (I. S. R.) are reviewed, together with results obtained in 1971 and 1972 on elastic scattering and total cross-sections. The main result is a 10% increase of the total proton-proton cross-section in the I. S. R. energy range. The simplest picture of high energy proton-proton scattering which emerges from this and the other data, is briefly discussed.


A summary of the work carried out at the Institute for High-Energy Physics, Serpukhov, U. S. S. R., on proton-proton interactions at energies between 10 and 70 GeV is given. The experiments comprise studies of small angle elastic scattering, of total cross-sections and of interactions in a hydrogen bubble chamber.


1985 ◽  
Vol 254 ◽  
pp. 697-736 ◽  
Author(s):  
G. Carboni ◽  
D. Lloyd Owen ◽  
K. Potter ◽  
M. Ambrosio ◽  
G. Barbarino ◽  
...  

2009 ◽  
Vol 679 (1) ◽  
pp. 30-35 ◽  
Author(s):  
T. Skorodko ◽  
M. Bashkanov ◽  
D. Bogoslawsky ◽  
H. Calén ◽  
H. Clement ◽  
...  

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