Search

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.

Experimental data on inclusive spectra measured in heavy-ion collisions at RHIC and SPS over a wide range of the energy \(\sqrt {s_{NN} } = 9 - 200\) GeV are analyzed in the framework of z scaling. A microscopic scenario of constituent interactions in the framework of this approach is discussed. Dependence of the energy loss on the momentum of the produced hadron, energy, and centrality of the collision, is studied. Self-similarity of the constituent interactions in terms of momentum fractions is used to characterize the nuclear medium by “specific heat” and colliding nuclei by fractal dimensions. Preferable kinematical regions for search for signatures of the phase transition of the nuclearmatter produced inHIC are discussed. Discontinuity of “specific heat” is assumed to be a signature of the phase transition and the Critical Point.

Experimental data on inclusive spectra of pions produced in heavy-ion collisions at RHIC are analyzed in the framework of z-scaling. The data indicate similarity as a characteristic feature of the mechanism of pion production at high energies. It is argued that this property includes structure of the colliding objects, interaction of their constituents, and character of the fragmentation process. A microscopic scenario of nucleus interactions at a constituent level in terms of momentum fractions is developed. The centrality dependence of the shape of the scaling function Ψ(z) and the fractal dimention ɛAA of the fragmentation process is studied. Energy losses of particles in the final state as a function of the collision energy, transverse momentum, and centrality are estimated. The scale dependence of the energy losses is discussed. A decreasing tendency of specific heat of the produced medium with the system size is established. The obtained results may be exploited to search for and study new physics phenomena in pion production in pp and AA collisions at high multiplicities.

The hypothesis of the self-similarity of hadron production in relativistic heavy-ion collisions to search for the phase transition in nuclear matter is discussed. Using the established features of z-scaling is suggested to reveal the signatures of new physics in the cumulative region. It is noted that selecting events on centrality in the cumulative region could help localize the position of a critical point. The change in the parameters of the theory (a specific heat and fractal dimensions) near the critical point is considered a signature of new physics. The relationship between the power asymptotic of Ψ(z) at high values of the similarity parameter z, the anisotropy of momentum space due to spontaneous symmetry breaking, and discrete (C, P, T) symmetries is emphasized.

Results of analysis of experimental data on inclusive spectra of charged hadrons produced in heavy-ion collisions at RHIC are shown in z presentation. The data indicate similarity as a characteristic feature of mechanism of hadron production at high energies. It is argued that this property includes structure of the colliding objects, interaction of their constituents, and character of the fragmentation process. Relation of the scaling variable z with the entropy and “specific heat” of the interacting system is discussed. A microscopic scenario of the constituent interactions connected with the momentum distribution of hadrons in the final state is suggested. We estimate energy losses of particles in the produced matter characterized by the multiplicity density dN ch/dη.

New experimental data on inclusive cross section of neutral-vector-meson (ω 0, ϕ, K 0 ) production in proton-proton collisions at $$ \sqrt s $$ = 200 GeV obtained at RHIC are analyzed in the framework of z scaling. Properties of z-presentation are used to predict hadron yields over a wide range of transverse momentum p T and collisions energy $$ \sqrt s $$ . The next-to-leading-order perturbative QCD calculations of inclusive cross sections of π 0 mesons produced in pp and $$ \bar p $$ collisions over a wide range of $$ \sqrt s $$ and p T are compared with ISR, S $$ \bar p $$ pS, RHIC data and predictions of z scaling. The dependence of the spectra in p T and z presentations for different parton distribution and fragmentation functions is studied. The sensitivity of the obtained results to the choice of the renormalization (µ R ), initial-state factorization (µ F ), and final-state factorization (fragmentation) (µ H ) scales is verified. It is shown that self-similar features of particle production dictated by the z scaling give strong restriction on the asymptotic behavior of the inclusive spectra in high-p T region.

Experimental data on transverse particle spectra obtained by the STAR, PHENIX, PHOBOS and BRAHMS collaborations at the RHIC are analyzed in the framework of the generalized concept of zscaling. It was developed for analysis of inclusive particle production in protonA(anti)proton collisions at high pT and high multiplicities. General scheme of the approach based on the physical principles of self-similarity, locality and fractality is reviewed. Independence of the scaling function ψ(z) from energy, multiplicity and atomic weight for h ± ,π ±,0 ,K 0 S, Λ hadrons produced in AuAAu and CuACu collisions at √ s = 130 and 200 GeV is discussed. Based on z-scaling the multiplicity dependence of pion transverse spectra up to pT =2 5GeV/c in AuAAu collisions at √ s = 200 GeV for experiments at the RHIC is predicted. �±¸¶¥·¨³¥´E ²O´O¥ ¤ ´´O¥ ¶μ ¶μ¶¥·¥I´O³ ¸¶¥±E· ³ I ¸E¨I, ¶μ²EI¥´´O¥ ±μ²² iμ· I¨O³¨

The multiplicity dependence of inclusive spectra of identified hadrons (π, K, \(\bar p\), KS0, and Λ) produced in high-energy \(\bar p\)p and pp collisions is studied. Analysis of experimental data on high-pT hadron cross sections obtained at the Tevatron and RHIC is performed in the framework of z scaling. Independence of the scaling function ψ(z) on the multiplicity density dNch/dη is established. The multiplicity density measured in nucleon-nucleon collisions reaches much higher values than the corresponding quantity [1/(0.5Np)]dNch/dη obtained in heavy-ion collisions. Its influence on particle production reveals properties of self-similarity and fractality. The relation between the scaling variable z and thermodynamic quantities (“heat capacity” and “temperature”) of the medium associated with the produced inclusive particle is discussed. Search for z-scaling violation in \(\bar p\)p and pp collisions at very high multiplicities as an indication of new-physics phenomena is suggested.

The influence of the cone algorithm parameters (E cut, E seed, R) on efficiency and characteristics of reconstructed jets in p-p collisions at the energy $$\sqrt s $$ = 200 GeV is studied. Event generation was carried out using the Monte Carlo code PYTHIA. The fraction of dijet event production as a function of transverse momentum of the hard process $$\hat p_ \bot $$ for different algorithm parameters is studied. The dependence of energy and parton direction reconstruction accuracy for dijet events and two leading jets in N-jet (N Jet ≥ 2) events on the algorithm parameters is found. The results of jet modeling are compared with predictions obtained in the framework of z-scaling and experimental data obtained at RHIC. It is proved that the slope parameter of the scaling function is independent of the algorithm parameters in the transverse jet energy range E T Jet = 25–60 GeV. It is shown that in the region E T Jet < 25 GeV, strong dependence of invariant cross sections and the slope of the scaling function on the algorithm parameters is observed, and this dependence is enhanced with decreasing E T Jet .

Generalization of z-scaling observed in the inclusive high-pT charged hadron and jet production is proposed. The scaling function psi(z) describing both charged hadrons and jets produced in proton-(anti)proton collisions for various multiplicity densities and collision energies is constructed. Anomalous fractal dimensions and parameters characterizing associated medium for both classes of events are established. The basic features of the scaling established in minimum bias events are shown to be preserved up to the highest multiplicity densities measured in experiments UA1, E735, CDF and STAR. The obtained results are of interest to use z-scaling as a tool for searching for new physics phenomena of particle production in high transverse momentum and high multiplicity region at the U70, Tevatron, RHIC and LHC., 13 pages, LaTeX, 11 figures, Presented at the VIII International Workshop "Relativistic Nuclear Physics: From MeV to TeV", Dubna, Russia, May 23 - 28, 2005

The concept of z-scaling reflecting the general regularities of high-pT particle production is reviewed. Properties of data z-presentation are discussed. New data on high-pT particle spectra obtained at the RHIC are analyzed in the framework of z-presentation. It was shown that these experimental data confirm z-scaling. Predictions of strange particle spectra are considered to be useful for understanding of strangeness origin in mesons and baryons and search for new physics phenomena at the RHIC., 16 pages, LaTeX, 27 figures, Presented at the XVII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics and Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 2004

The concept of z scaling reflecting the general features of high-pT particle production is reviewed. Properties of data z presentation are discussed. New data on high-pT particle spectra obtained at the RHIC and Tevatron are analyzed in the framework of z presentation. It was shown that these experimental data confirm z scaling. The change in the anomalous fractal dimensions of colliding objects (“δ jump”) is considered as a signature of new physics. The kinematic ranges preferable for searching for z-scaling violation are established.

The general features of particle production in hadron-hadron and hadron-nucleus collisions at high energy and transverse momentum using the concept of z-scaling are reviewed. z-Presentation of experimental data on the inclusive cross sections obtained at ISR, SPS, and Tevatron is presented and its properties are discussed. It is argued that the properties reflect the fundamental symmetries such as self-similarity, locality, and fractality. z-Scaling is used to predict particle yields in hadron-hadron and hadron-nucleus collisions at RHIC and LHC energies. The violation of z-scaling is considered as a signature of new physics phenomena.

The A-dependence of z-scaling in inclusive hadron production in pA collisions at high transverse momenta is studied. The concept of z-scaling based on the fundamental principles of Nature such as self-similarity, locality, scale relativity and fractality reflecting the general features of particle interactions is applied for the description of processes of hadron production in pA collisions. The scaling function ψ is expressed via the invariant cross-section Ed3σ/dq3 and the average multiplicity density dN/dη of particles produced at pseudorapidity η=0 in the corresponding nucleon–nucleon interaction. The independence of the function ψ(z) on the center-of-mass energy [Formula: see text] for particle production near 90° in the NN c.m. system for different nuclei from D up to Pb is shown. The scale transformation z→az, ψ→a-1ψ is used to determine the A-dependence of the transformation parameter a. Based on the properties of z-scaling the dependence of the cross-sections for the π±, K±, and [Formula: see text] hadrons produced in pA collisions on transverse momentum q⊥ in the central region (η=0) at RHIC energies is predicted.

Inclusive jet production in [Formula: see text] and pp collisions at high energies in the framework of the concept of z-scaling is studied. The available experimental data on the cross-section of jet production obtained by the UA1, UA2, CDF and D0 Collaborations are used for analysis. The scaling function ψ(z) is expressed via inclusive cross-section Ed3σ/dq3 and jet multiplicity density ρ(s,η). The properties of z-scaling, the energy and angular independence of ψ(z) and the power behavior, ψ(z)~z-α, of jet and dijet production were found. Based on the properties of z-scaling, the dependence of the cross-section of jets produced in [Formula: see text] and pp collisions on transverse momentum q⊥ over the central range is predicted. The obtained results can be of interest for future experiments planned at RHIC, LHC, HERA and Tevatron to search for new phenomena in hadron–hadron, hadron–nucleus and nucleus–nucleus collisions.

A detailed NNLO QCD analysis of new CCFR data on the $xF_3$ structure function including the target mass, higher twist and nuclear corrections was performed and parametrizations of the perturbative and power terms of the structure function were constructed. The results of QCD analysis of the structure function were used to study the $Q^2-$dependence of the Gross-Llewellyn Smith sum rule. The $\alpha_S/\pi-$expansion of $S_{GLS}(Q^2)$ was studied and parameters of the expansion were found to be $s_1=2.74\pm 0.01$, $s_2=-2.22\pm 0.23$, $s_3=-7.86\pm 1.74$ in a good agreement with the perturbative QCD predictions for the Gross-Llewellyn Smith sum rule in the next-to-leading and next-to-next-to-leading order., Comment: 10 pages, latex, 3 figures . Reported at Inernational Syposium "Dubna Deuteron-97" (Dubna, July 2-5, 1997)

The deep-inelastic deuteron structure function (SF) $F_2^D(x_D,Q^2)$ in the covariant approach in light-cone variables is considered. The $x_D$ and $Q^2$-dependences of SF are calculated. The QCD analysis of generated data both for non-cumulative $x_D1$ ranges was performed. It was shown that $Q^2$-evolution of SF is valid for ranges $0.275, Comment: LaTeX, 10 pages, 2 Postscript figures

The treatment results of the acute iliopsoitis in 29 patients were analyzed. The right side inflammation was observed more frequently (n=17). The most common infectious agent was the Staphylococcus aureus. The source of the inflammation was septic lesions of the lower body, whereas the perdisposal factors were considered to be the diabetes mellitus, drug abuse and immunodeficiency. The cardinal diagnostic sign of the acute iliopsoitis proved to be the psoas-symptom. The main diagnostic instruments were the ultrasound investigation, CT and MRI. 1 patient was successfully treated conservatively, though the rest 28 demanded surgical opening and drainage of m. iliopsoas. The lethality rate was 3,4%. 96,6% of the treated patients were successfully cured.

New experimental data on inclusive spectra of identified particles produced in pp collisions at the RHIC are used to test z-scaling. Energy and multiplicity independence of the scaling function is established. The RHIC data confirm z-scaling observed at U70, ISR, SpS and Tevatron energies. The obtained results are of interest to search for new physics phenomena of particle production in high transverse momentum and high multiplicity region at RHIC, Tevatron and LHC., Comment: 6 pages, LaTeX, 12 figures, Presented at the XXXV International Symposium on Multiparticle Dynamics, Kromeriz, Czech Republic, August 9-15, 2005

The average particle multiplicity density dN/deta is the dynamical quantity which reflects some regularities of particle production in low-pT range. The quantity is an important ingredient of z-scaling. Experimental results on charged particle density are available for pp, pA and AA collisions while experimental properties of the jet density are still an open question. The goal of this work is to find the variable which will reflect the main features of the jet production in low transverse energy range and play the role of the scale factor for the scaling function psi(z) and variable z in data z-presentation. The appropriate candidate is the variable we called "scaled jet energy density". Scaled jet energy density is the probability to have a jet with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of scaled jet energy density in proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and at eta = 0. The properties of the new variable are discussed and sensitivity to "physical scenarios" applied in the standard Monte Carlo generator is noted. The results of scaled jet energy density at LHC energies are presented and compared with predictions based on z-scaling., Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics & Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 2004

The authors demonstrate that though some relativistic effects in the nucleon momentum distribution in the deuteron are important in the momentum region k>0.3 GeV/c, these effects can nevertheless not account for the discrepancy between the experimentally measured distribution and the results of theoretical calculations based on two-nucleon wavefunctions. Apart from this, the role of the P wave in the nucleon momentum distribution in the deuteron is discussed.

In the framework of a covariant formalism relying on a relativistic deuteron wave function (RDWF) with one nucleon on the mass shell one deals with an exclusive deuteron electrodisintegration process in the impulse approximation. The influence of the off-shell effect of the RDWF on possible analytic and dynamic cross-section factorizations is investigated. Contributions of direct and interference electrodisintegration amplitudes have been calculated taking into account the off-shell behavior of the electromagnetic nucleon vertex. Corresponding results are compared with data on three kinematics of the SaclayD(e, e p)n experiments. It is shown that off-shell effects both of the RDWF and electromagnetic nucleon vertex must be considered properly in order to get reliable information on the high-momentum component of the RDWF.