Results on system size dependence of strangeness production in the CERN SPS energy range from NA61/SHINE

NA61/SHINE is a multipurpose fixed-target facility at the CERN Super Proton Synchrotron. The main goals of the NA61/SHINE strong interactions program are to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. To reach these goals, hadron production measurements are performed in the form of a two-dimensional scan by varying collision energy and system size. The Collaboration has recently finished data acquisition for its original program on strong interactions, accumulating broad data samples on hadron production in various systems in the SPS energy range.\\ In this contribution, the NA61/SHINE results on identified charged kaon and pion production in p+p, Be+Be and Ar+Sc collisions at the SPS energy range ($\sqrt{s_{NN}}$=5.1--17.3 GeV) are presented. The NA61/SHINE measurements of small and intermediate-mass ion collisions establish an interesting system size dependence, showing a rapid change of hadron production properties that starts when moving from Be+Be to Ar+Sc system. In particular, Ar+Sc is the smallest system for which a significant enhancement of $K^+/\pi^+$ ratio with respect to $p$+$p$ collisions is observed. Obtained energy and system size dependence of the measured charged hadron multiplicities are compared with available world data and various theoretical models

Study of charged hadron production with tof-dE/dx identification method in central Ar+Sc collisions in NA61/SHINE experiment at CERN

This thesis presents results on inclusive spectra of protons, anti-protons, $\pi^+$, $\pi^-$, $K^+$ and $K^-$ in 10% of the most central $^{40}$Ar+$^{45}$Sc collisions. Data on Ar+Sc collisions were collected by the NA61/SHINE experiment at the CERN SPS. Results are presented for six beam momenta: 13$A$, 19$A$, 30$A$, 40$A$, 75$A$, and 150$A$ GeV/$c$. This is the first measurement of hadron production in Ar+Sc collisions in the SPS energy range. Identification of charged particles was performed via the \tofdedx method. The method is based on the simultaneous measurement of particle energy loss in the Time Projection Chambers and time-of-flight through the detector. Two-dimensional particle spectra are presented as a function of rapidity and transverse momentum. The results include corrections for various effects related to detector and reconstruction procedure efficiencies and particles originating from weak decays. Special attention was paid to the production of $K$ mesons, lightest strange particles produced in heavy ion collisions. Transverse momentum spectra of charged kaons in mid-rapidity were parametrized with a Boltzmann-like exponential function. The parametrization yielded values for the inverse slope parameter $T$ and enabled the calculation of kaon yields in mid-rapidity. Strangeness production in mid-rapidity was studied in the scope of the onset of deconfinement in intermediate-mass nuclei at the CERN SPS energy range. Hadron production in Ar+Sc interactions is part of the main program of NA61/SHINE related to the study of the onset of deconfinement and the search for the critical point in strongly-interacting matter. The results presented in this thesis were compared with hadron production measurements in $p$+$p$, Be+Be, and Pb+Pb collisions recorded by the NA61/SHINE and NA49 experiments. Moreover, a comparison with predictions of three microscopic theoretical models was provided

The Forward TPC system of the NA61/SHINE experiment at CERN: a tandem TPC concept

This paper presents the Forward Time Projection Chamber (FTPC) system of the NA61/SHINE experiment at the CERN SPS accelerator. This TPC system applies a novel tandem-TPC design to reduce the background originating from particle tracks not synchronous with the event trigger. The FTPC system is composed of three chambers with alternating drift field directions. The chambers were installed directly along the beamline region of the NA61/SHINE detector in a medium- to high-intensity (10-100 kHz) hadron or ion beam. The tandem TPC system has proved to be capable of rejecting out-of-time background tracks not associated with a primary interaction. In addition, the system performs tracking and inclusive dE/dx particle identification for particles at and near the beam momentum. This shows that a tandem-TPC-based chamber design may be used also in other experimental applications with a demand for low material budget, tracking capability, and the need for dE/dx particle identification, all while in the presence of a relatively high particle flux

Erratum to: Measurements of Ξ− and Ξ ¯+ production in proton–proton interactions at √sN N = 17.3 GeV in the NA61/SHINE experiment

his Erratum replaces incorrect plots shown in Fig. 7 with the corrected ones. In the publication, the NA57 [1] ratios of Ξ− and Ξ¯¯¯¯+ to the number of wounded nucleons at ⟨NW⟩=349 by mistake were plotted at the wrong values. The ratios were calculated and plotted by mistake using ⟨NW⟩=249. The correct normalization does not change the conclusions of the paper. The correctly normalized results are presented in Fig. 7