arXiv subjects

Alberto Giovannini

Publications and source records attributed to Alberto Giovannini.

10 recordsLinked to original sources

arXiv2004

Main results of a search on multiplicity distributions in pp collisions: is anybody afraid of a new class of hard events?

After an introduction on possible scenarios in the TeV energy region in pp collisions, extrapolated from the knowledge of the GeV energy region, attention is focused on the onset of a third class of events, harder than the semi-hard and soft ones identified at SpS and Tevatron. The expected features and signatures in multiplicity fluctuations, forward-backward correlations and collision energy density are discussed.

hep-ph↗

arXiv2004

Clan structure analysis and new physics signals in pp collisions at LHC

The study of possible new physics signals in global event properties in pp collisions in full phase space and in rapidity intervals accessible at LHC is presented. The main characteristic is the presence of an elbow structure in final charged particle MD's in addition to the shoulder observed at lower c.m. energies.

hep-ph↗

arXiv2004

Scenarios for multiplicity distributions in pp collisions in the TeV energy region

Possible scenarios based on available experimental data and phenomenological knowledge of the GeV energy region are extended to the TeV energy region in the framework of the weighted superposition mechanism of soft and semi-hard events. KNO scaling violations, forward-backward multiplicity correlations, Hq vs. q oscillations and shoulder structures are discussed.

hep-ph↗

arXiv2002

Questions and Remarks About Clans in Multiparticle Dynamics

The fact that several important effects in multiparticle dynamics, on which QCD has not yet satisfactory predictions, have been interpreted in terms of the validity of negative binomial (Pascal) regularity and related clan properties at the level of simpler substructures, raises intriguing questions on clan properties in all classes of collisions, the main one being whether clans are observable objects or merely a mathematical concept. We approach this problem by studying clan masses and rapidity distributions in each substructure for e+e- annihilation and hh collisions, and find that such properties can indeed characterise the different components. These results support the idea that clans could be observable, a challenging problem for future experiments.

hep-ph↗

arXiv2002

Global event properties in proton-proton physics with ALICE

ALICE is a unique opportunity for studying low Pt physics and minimum bias events, and consequently for hunting substructures in strong interactions. The general question concerning global event properties in pp and ppbar physics is indeed whether substructures can be seen in the data in a model-independent way. In other terms, can we identify the interface between perturbative and non-perturbative regimes?

hep-ph↗

arXiv2002

Correlations in proton-proton collisions with ALICE

Particle correlations and particle multiplicity distributions cannot be approached independently: a unified description of correlations and multiplicity distributions is always needed in order to understand the underlying dynamics in high energy collisions. In this light, we review the most recent and interesting results on rapidity and momentum correlations, emphasising the possibilities of measurements with the ALICE detector.

hep-ph↗

arXiv2002

Thermodynamics of Clan Production

Scenarios for particle production in the GeV and TeV regions are reviewed. The expected increase with c.m. energy of the average number of clans for the soft component and the decrease for the semihard one indicate possible classical and quantum behaviour of gluons, respectively. Clan thermodynamics, discussed in the paper, appears as the natural framework to deal with such phenomena.

hep-ph↗

arXiv1996

Common origin of the shoulder structure and of the oscillations of moments in multiplicity distributions in e(+)e(-) annihilations

We show, via a simple parametrization of the multiplicity distribution of charged particles in e(+)e(-) annihilation at the Z0 peak in terms of the weighted superposition of two negative binomial distributions, that both the shoulder structure in the intermediate multiplicity range and the oscillation in sign of the ratio of factorial cumulants over factorial moments of increasing order are related to hard gluon radiation.

hep-ph↗

arXiv1996

The negative binomial distribution in quark jets with fixed flavour

We show that both the multiplicity distribution and the ratio of factorial cumulants over factorial moments for 2-jet events in e+e- annihilation at the Z^0 peak can be well reproduced by the weighted superposition of two negative binomial distributions, associated to the contribution of $b\bar b$ and light flavoured events respectively. The negative binomial distribution is then suggested to describe the multiplicity distribution of 2-jet events with fixed flavour.

hep-ph↗

arXiv1996

Common origin of the shoulder in multiplicity distributions and of oscillations in the factorial cumulants to factorial moments ratio

The shoulder structure of charged particles multiplicity distributions (MD's) in full phase space in $e^+e^-$ annihilation at the $Z_0$ peak and the quasi-oscillatory behavior of the ratio of factorial cumulants over factorial moments, $H_q$, as a function of the order $q$, are quantitatively reproduced within a simple parametrization of the MD in terms of a weighted superposition of two Negative Binomial Distributions, associated to two- and multi-jet production, i.e., to hard gluons radiation.

hep-ph↗