Research Article
Charged-Particle Multiplicity Moments as Described
by Shifted Gompertz Distribution in
+
-
, , and Collisions
at High Energies
Aayushi Singla and M. Kaur
Physics Department, Panjab University, Chandigarh 160014, India
Correspondence should be addressed to M. Kaur; manjit@pu.ac.in
Received 8 March 2019; Revised 3 July 2019; Accepted 20 August 2019; Published 25 January 2020
Academic Editor: eocharis Kosmas
Copyright © 2020 Aayushi Singla and M. Kaur. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
e publication of this article was funded by SCOAP
3
.
In continuation of our earlier work, in which we analysed the charged particle multiplicities in leptonic and hadronic interactions at
different center-of-mass energies in full phase space as well as in restricted phase space using the shiſted Gompertz distribution, a
detailed analysis of the normalized moments and normalized factorial moments is reported here. A two-component model in which
a probability distribution function is obtained from the superposition of two shiſted Gompertz distributions, as introduced in our
earlier work, has also been used for the analysis. is is the first analysis of the moments with the shiſted Gompertz distribution.
Analysis has also been performed to predict the moments of multiplicity distribution for the
+
-
collisions at √ = 500 GeV at
a future collider.
1. Introduction
In one of our recent papers, we introduced a statistical
distribution, the shiſted Gompertz distribution to investigate
the multiplicity distributions of charged particles produced in
+
-
collisions at the LEP, interactions at the SPS and
collisions at the LHC at different center of mass energies in
full phase space as well as in restricted phase space [1]. A
distribution of the larger of two independent random variables,
the shiſted Gompertz distribution was introduced by Bemmaor
[2] as a model of adoption of innovations. One of the
parameters has an exponential distribution and the other has
a Gumbel distribution, also known as log-Weibull distribution.
e nonnegative fit parameters define the scale and shape of
the distribution. Subsequently, the shiſted Gompertz
distribution has been widely studied in various contexts [3–5].
In our earlier work [1] by studying the charged particle
multiplicities, we showed that this distribution can be
successfully used to study the statistical phenomena in high
energy
+
-
, , and collisions at the LEP, SPS, and LHC
colliders, respectively.
A multiplicity distribution is represented by the proba-
bilities of -particle events as well as by its moments or its
generating function. e aim of the present work is to extend
the analysis by calculating the higher moments of a multi-
plicity distribution. Because the moments are calculated as
derivatives of the generating function, the moment analysis
is a powerful tool which helps to unfold the characteristics
of multiplicity distribution. e multiparticle correlations
can be studied through the normalized moments and nor-
malized factorial moments of the distribution. e depend-
ence of moments on energy can also reveal the KNO (Koba,
Nielsen, and Olesen) scaling [6–8] conservation or violation.
Several analyses of moments have been done at different
energies, using different probability distribution functions
and different types of particles [9–12]. e higher moments
also can identify the correlations amongst produced
particles.
In Section 2, formulae for the probability distribution
function (PDF) of the shiſted Gompertz distribution, normal-
ized moments, and the normalized factorial moments used
for the analysis are given. A two-component model has been
used and modification of distributions carried out, in terms
of these two components; one from soſt events and another
from semi-hard events. Superposition of distributions from
these two components, using appropriate weights is done to
Hindawi
Advances in High Energy Physics
Volume 2020, Article ID 5192193, 24 pages
https://doi.org/10.1155/2020/5192193