arXiv subjects

NA22 Collaboration

Publications and source records attributed to NA22 Collaboration.

4 recordsLinked to original sources

arXiv2005

Boost Invariance and Multiplicity Dependence of the Charge Balance Functionin $π^{+}p$ and $K^{+}p$ Collisions at $\sqrt s= 22$ GeV/c

Boost invariance and multiplicity dependence of the charge balance function are studied in $π^{+}\rp$ and $\rK^{+}\rp$ collisions at 250 GeV/$c$ incident beam momentum. Charge balance, as well as charge fluctuations, are found to be boost invariant over the whole rapidity region, but both depend on the size of the rapidity window. It is also found that the balance function becomes narrower with increasing multiplicity, consistent with the narrowing of the balance function when centrality and/or system size increase, as observed in current relativistic heavy ion experiments.

hep-ex↗

arXiv2005

Entropy Analysis in $π^{+}\rp$ and $\rK^{+}\rp$ Collisions at $\sqrt{s}=22$ GeV

The entropy properties are analyzed by Ma's coincidence method in $π^{+}\rp$ and $\rK^{+}\rp$ collisions of the NA22 experiment at 250 GeV/$c$ incident momentum. By using the Rényi entropies, we test the scaling law and additivity properties in rapidity space. The behavior of the Rényi entropies as a function of the average number of particles is investigated. The results are compared with those from the {\sc Pythia} Monte Carlo event generator.

hep-ex↗

arXiv1997

Estimation of Hydrodynamical Model Parameters from the Invariant Spectrum and the Bose-Einstein Correlations of pi-mesons Produced in (pi+/K+)p Interactions at 250 GeV/c

The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250 GeV/c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity = 0.20(7), and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be Delta eta = 1.36(2). Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of = 1.4(1) fm/c and its transverse geometrical rms radius, R_G (rms)=1.2(2) fm.

hep-ex↗

arXiv1996

Large Self-affine fractality in $\p^+$p and K$^+$p collisions at 250 GeV/$c$

Taking into account the anisotropy of phase space in multiparticle production, a self-affine analysis of factorial moments was carried out on the NA22 data for $\p^+\Pp$ and $\PK^+\Pp$ collisions at 250 GeV/$c$. Within the transverse plane, the Hurst exponents measuring the anisotropy are consistent with unit value (i.e. no anisotropy). They are, however, only half that value when the longitudinal direction is compared to the transverse ones. Fractality, indeed, turns out to be self-affine rather than self-similar in multiparticle production. In three-dimensional phase space, power-law scaling is observed to be better realized in self-affine than in self-similar analysis.

hep-ex↗