Narrow Results

The phenomenology of multi-particle production of hadrons is reviewed, with emphasis on the results at the Large Hadron Collider (LHC): the first part of the review focuses on the basic kinematic measurements of charged tracks and identified hadrons in minimum bias interactions; the second part reports the short- and long-range correlation studies; the third part concentrates on the underlying event phenomenology in different final states; the fourth part, which constitutes a bottom line on the phenomenology of multiple parton interactions, considers the consequences of multiple hard-scatterings in a single hadron–hadron collisions. Some relevant highlights from the heavy ion program are also discussed.

Charged hadron production in the $e^{+}{e}^{-}$ annihilations at 91 to 206GeV in full phase space and in $\overline{p}p$ collisions at 200 to 900GeV collision energies are studied using nonextensive Tsallis and stochastic Weibull probability distributions. The Tsallis distribution shows better description of the data than the Weibull distribution. The 2-jet modification of the statistical distribution is applied to describe $e^{+}{e}^{-}$ data. The main features of these distributions can be described by a two-component model with soft, collective interactions at low transverse energy and hard, constituent interactions dominating at high transverse energy. This modification is found to give much better description than a full-sample fit, and again Tsallis function is found to better describe the data than the Weibull one pointing at the nonextensive character of the multiparticle production process.

We analyze the charged-particle multiplicity distributions measured by the ALICE experiment, over a wide pseudorapidity range, for $pp$ collisions at $\sqrt{s}=8$, 7 and 2.76 TeV at the LHC. The analysis offers an understanding of particle production in high energy collisions in the purview of a new distribution, the shifted Gompertz distribution. Data are compared with the distribution and moments of the distributions are calculated. A modified version of the distribution is also proposed and used to improve the description of the data consisting of two different event classes: the inelastic and the nonsingle diffractive and their subsets in different windows of pseudorapidity, $\eta$. The distribution used to analyze the data has a wide range of applicability to processes in different fields and complements the analysis done by the ALICE collaboration in terms of various LHC event generators and IP-Glasma calculations.