NA49 and NA61/SHINE experiments: results and perspectives

The Super Proton Synchrotron (SPS) covers one of the most interesting regions of the QCD phase diagram $(T - \mu_B)$. On the one hand there are indications that the energy threshold for deconfinement is reached already at low SPS energies. On the other hand theoretical calculations locate the QCD critical end-point at energies accessible at the SPS. In this paper the NA49 signatures of the onset of deconfinement are presented. Results are shown on pion production, the kaon to pion ratio, slopes of transverse mass spectra ("temperature"), and event-by-event particle ratio fluctuations versus collision energy, for central $Pb+Pb$ interactions. Next we show possible indications of the critical point in event-by-event mean transverse momentum and multiplicity fluctuations. Finally we discuss the future ion program of the NA61/SHINE experiment (energy scan with light ions).Comment: Lecture given at XXXI Mazurian Conference on Physics (August 30 - September 6, 2009, Piaski, Poland); first paragraph of page 7 (second sentence, HGM model) - modifie

Influence of Impact Parameter Fluctuations on Transverse Momentum Fluctuations

The preliminary NA49 results on the energy dependence of transverse momentum fluctuations over the whole SPS energy range exhibit an unexpected effect. The $\Phi_{p_{T}}$ fluctuation measure - used by the NA49 experiment - manifests a different behavior for different charge combinations. Whereas the $\Phi_{p_{T}}$ is consistent with zero and independent of energy for negatively charged particles, it significantly increases for both all charged and positively charged particles at lower SPS energies. The string-hadronic model UrQMD is applied here to explain this effect. The UrQMD simulations show that the number of protons is strongly correlated with impact parameter and that the event-by-event impact parameter fluctuations are responsible for the event-by-event transverse momentum fluctuations of positively charged and all charged particles where protons are included. The observations presented in this article are important for all experiments measuring event-by-event fluctuations, especially for those using all charged particles in the analysis. The results can be also crucial for detectors with acceptances extending to the beam/target spectator domains.Comment: Errata: Section 4, the end of the first paragraph - sentence in brackets modifie

Search for the critical point of strongly interacting matter in NA49

Theoretical calculations locate the QCD critical point at energies accessible at the CERN SPS. Several observables were suggested to look for it. Here, we present the system size dependence and the energy dependence of event-by-event mean transverse momentum and multiplicity fluctuations, as well as the energy dependence of anti-baryon to baryon ratios.Comment: Quark Matter 2009 proceedings, 4 pages; Caption of Fig. 1 and one line in Fig. 6 modified (for better black and white print

News from strong interactions program of the NA61/SHINE experiment

The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. This is performed by a two dimensional phase diagram ($T-\mu_B$) scan of measurements of particle spectra and fluctuations in proton-proton, proton-nucleus and nucleus-nucleus interactions as a function of collision energy and system size. In this contribution new NA61/SHINE results on negative pion production, as well as transverse momentum and multiplicity fluctuations in Ar+Sc collisions are presented. Moreover, the latest results on higher order moments of net-charge multiplicity distribution in p+p collisions are also discussed. The Ar+Sc results are compared to NA61 p+p and Be+Be data, as well as to NA49 $A+A$ results.Comment: Presented at the Critical Point and Onset of Deconfinement 2016, Wroclaw, Poland, May 30th - June 4th, 2016 (v2: Fig. 2 - labels corrected, references updated

Hot strong matter

The recent results on relativistic heavy-ion collisions are discussed. The most convincing quark-gluon plasma signatures at the LHC and the top RHIC energies are presented. Moreover, the possible methods of evaluating the energy threshold for deconfinement (onset of deconfinement) are described, and the corresponding results from the RHIC Beam Energy Scan and the SPS programs are shown. Additionally, the first signatures of creating dense and collectively behaving systems in collisions of small nuclei (or even in elementary interactions) are discussed. Finally, the current status of experimental search for the critical point of strongly interacting matter is summarized.Comment: 20 pages, to appear in the proceedings of DIS 2014 workshop, Warsaw, Poland, 28/4-2/5, 201

Report from NA49

The signatures of the onset of deconfinement, found by the NA49 experiment at low SPS energies, are confronted with new results from the Beam Energy Scan (BES) program at BNL RHIC and CERN LHC results. Additionally, new NA49 results on chemical (particle ratio) fluctuations, azimuthal angle fluctuations, intermittency of di-pions, etc. are presented.Comment: 8 pages, proceedings from "Strangeness in Quark Matter", September 18-24, Krako