Multiplicity distributions of charged particles measured by the ATLAS Collaboration in proton–proton collisions at
s
=
8
and 13 TeV are analyzed in the framework of a weighted superposition of three ...negative binomial distribution functions. The examination of the experimental data confirms the existence of a narrow peak at low multiplicities found earlier at
s
=
0.9
and 7 TeV. The peak is described by the third separate component of the total distribution. The energy dependence of the multiplicity characteristics of the three-component scenario is studied. It is demonstrated that the third multiplicity component might be responsible for oscillations of combinants observed lately in the analysis of the multiplicity distributions measured in proton–proton collisions at the LHC. Some consequences of the three-component description of the data for the clan parameters are analyzed.
We present results of analysis of hadron production in
and
collisions obtained in the framework of
z
-scaling in searching for signatures of a phase transition in nuclear matter. The approach allows ...systematic analysis of experimental data on inclusive cross sections over a wide range of the collision energies, multiplicity densities, transverse momenta, and angles of various particles. The concept of the
z
‑scaling is based on the principles of self-similarity, locality and fractality reflecting the general features of hadron interactions. The scaling function
depends on the self-similarity variable
z
and is expressed by the inclusive cross-section and the multiplicity density of produced particles. The variable
z
is a function of the momentum fractions
and
of the colliding objects carried by interacting hadron constituents and depends on the fractions
and
of the scattered and recoil constituents carried by the inclusive particle and its recoil counterpart. There are three model parameters in the
z
-scaling approach. Structure of the colliding objects and fragmentation processes are characterized by the structural and fragmentation fractal dimensions δ and
, respectively. The produced medium is described by a “specific heat”
c
. The discontinuity of the model parameters is discussed from the point of view of searching for phase transitions in nuclear matter.
-Scaling of inclusive spectra as a manifestation of self-similarity and fractality of hadron interactions is illustrated. The scaling for negative particle production in
collisions from BES-I program ...at RHIC is demonstrated. The scaling variable
depends on the momentum fractions of the colliding objects carried by the interacting constituents, and on the momentum fractions of the fragmenting objects in the scattered and recoil directions carried by the inclusive particle and its counterpart, respectively. Structures of the colliding objects and fragmentation processes in final state are expressed by fractal dimensions. Medium produced in the collisions is described by a specific heat. The scaling function
reveals energy, angular, multiplicity, and flavor independence. It has a power behavior at high
(high
). Based on the entropy principle and
-scaling, energy loss as a function of the collision energy, centrality and transverse momentum of inclusive particle is estimated. New conservation law including fractal dimensions is found. Quantization of fractal dimensions is discussed.
New experimental data on transverse momentum spectra of strange particles (K0S,K-, K*, φ, ...) produced in pp collisions at √s = 200 GeV obtained by the STAR and PHENIX collaborations at RHIC are ...analysed in the framework of z-scaling approach. Scaling properties of the data z-presentation are illustrated. Self-similarity of strange particle production is discussed. A microscopic scenario of constituent interactions developed within the z-scaling approach is used to study constituent energy loss, proton momentum fraction and recoil mass in dependence on the transverse momentum, strangeness, and mass of the inclusive particle. The obtained results can be useful for understanding strangeness origin, for searching for new physics with strange probes and can serve as a benchmark for complex analyses of self-similar features of strange production in heavy ion collisions.
The concept of z-scaling previously developed for analysis of inclusive reactions in proton-proton collisions is applied for description of processes with polarized particles. Hypothesis of ...self-similarity of the proton spin structure is discussed. The possibility of extracting information on spin-dependent fractal dimensions of hadrons and fragmentation process from the cross sections and asymmetries is justified. The double longitudinal spin asymmetry ALL of jet and π0-meson production and the coefficient of polarization transfer DLL measured in proton-proton collisions at √s = 200 GeV at RHIC are analyzed in the framework of z-scaling. The spin-dependent fractal dimension of proton is estimated.
Results of a new analysis of negative particle yields in Au + Au collisions obtained by the STAR Collaboration in the first phase of the RHIC Beam Energy Scan (BES) program in the framework of
...-scaling approach are presented. The spectra were measured over a wide range of collision energy
GeV and transverse momentum of produced particles for different centralities at
The concept of the
-scaling based on self-similarity, locality, and fractality of hadron interactions at a constituent level is verified. The constituent energy loss as a function of energy and centrality of collision and transverse momentum of inclusive particle was estimated.
We present new results of analysis of top-quark differential cross sections obtained by the CMS Collaboration in pp collisions in the framework of the z-scaling approach. The spectra are measured ...over a wide range of collision energy s = 7 , 8 , 13 T e V and transverse momentum pT = 30−500 GeV/c of top-quark using leptonic and jet decay modes. Flavor independence of the scaling function ψ(z) is verified in the new kinematic range. The results of analysis of the top-quark spectra obtained at the LHC are compared with similar spectra measured in p ¯ p collisions at the Tevatron energy s = 1.96 T e V . A tendency to saturation of ψ(z) for the process at low z and a power-law behavior of ψ(z) at high z is observed. The measurements of high-pT is observed. The measurements of highspectra of the top-quark production at highest LHC energy is of interest for verification of self-similarity of particle production, understanding flavor origin and search for new physics symmetries with top-quark probe.
We briefly review
z
-scaling as a reflection of the self-similarity of hadron production in high-energy hadron and nuclear collisions and discuss the basic principles of constituent interactions ...(locality, self-similarity, and fractality). We present results of analyzing experimental data on the inclusive pT spectra of hadron and jet production at the RHIC, Tevatron, and LHC in the framework of
z
-scaling.
Self-similarity of jet production in polarized
p
+
p
collisions is studied. The concept of
z
-scaling is applied for description of proton spin. New data on the double longitudinal spin asymmetry,
A
...LL
, of inclusive jets produced in proton-proton collisions at √
s
= 200 GeV measured by the STAR Collaboration at RHIC are analyzed in the framework of
z
-scaling approach. A hypothesis of self-similarity and fractality of the proton spin structure are formulated. A possibility to extract information on spin-dependent fractal dimensions of proton from the asymmetry of jet production is justified. The spin-dependent fractal dimension of proton in process
is estimated.
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