1 Measurements and analysis for strong interaction program of NA61/SHINE at SPS Grigory Feofilov (St.Petersburg State University,RF), for NA61(SHINE) Collaboration From 12 to 15 April 2016, the Section of Nuclear Physics of the Physical Sciences Division of the Russian Academy of Sciences (SNP PSD RAS) and the Joint Institute for Nuclear Research (JINR) will hold at JINR, Dubna, Moscow Region, an International Session-Conference of SNP PSD RAS "Physics of Fundamental Interactions"..

2 Outline 1)Introduction. 2)Strong interaction program of NA61/SHINE at SPS 3)Measurements 4)Analysis 5)Summary Followed by the NA61/SHINE talks at this session: S.Morosov (INR, RAS), NA61/SHINE experiment at CERN SPS A.Seryakov (SPbSU), Energy scan of correlations in p+p and Be+Be from NA61/SHINE E.Andronov (SPbSU), Energy dependence of fluctuations in p+p and Be+Be collisions from NA61/SHINE

3 NA61/SHINE SPS Heavy Ion and Neutrino Experiment, two pillars: 1)study the properties of the onset of deconfinement and search for the critical point of strongly interacting matter which is pursued by investigating p+p, p+Pb and nucleus-nucleus collisions 2)precise hadron production measurements for improving calculations of the initial neutrino beam flux in the long-baseline neutrino oscillation experiments as well as for more reliable simulations of cosmic-ray air showers.

Phases of strongly interacting matter Search for evidence for the energy threshold of creating the quark-gluon plasma in nucleus- nucleus collisions and onset of deconfinement M – is the critical point of the nuclear liquid - gas phase E -- is the critical end-point of the 1 st order phase transition Shaded band -- the 1st order phase boundary between the hadron and QGP phase which is expected to end in a critical end point E 4 M.Gazdzicki M.Gorenstein and Peter Seyboth arXiv:

5 See references in M.Gazdzicki M.Gorenstein and Peter Seyboth arXiv: Some first experimental results:

Open question: Does the CP exist? Z.Fodor, S.Katz: JHEP 04,50(2004) -- Yes A.Li, A.Alexandru, K.-F.Liu: PRC D84,071503(2011) -- Is not observable in AA Ph.de Forcrand, O.Philipsen: JHEP 11,012(2008) G.Endro ̈ di, Z.Fodor, S.Katz, K.Szabo: JHEP 1104,001(2011) --No  Experimental studies are required 6

Observables and variables n – number of charged particles in given rapidity window pt – mean event transverse momentum of charged particles in given window Particle charge sign Particle ratious 7

“Hill” of fluctuations Strongly intensive quantities for some extensive observable A and B : 8 The scaled variance Gorenstein M I and Gazdzicki M 2011 Phys. Rev. C Gazdzicki M, Gorenstein M I and Mackowiak-Pawlowska M 2013 Phys. Rev. C

NA49 at SPS: Energy dependence of multiplicity fluctuations in heavy ion collisions at 20 A to 158 A GeV and search for critical point 9 FIG. 34. (Color online) Top: Scaled variance ω of the multiplicity distribution of negatively charged hadrons at forward rapidities produced in central Pb+Pb collisions as a function of the baryo- chemical potential μ B [48]. A sketch of the expected increase of ω due to the critical point [13,51] is also shown. The UrQMD results are given for a centrality selection similar to the experimental data. Bottom: Ratio of ω in data and UrQMD as a function of μ B. [13] M. A. Stephanov, K. Rajagopal, and E. V. Shuryak, Phys. Rev. D 60, (1999).  No sign of increased fluctuations as expected for a freeze- out near the critical point of strongly interacting matter was observed

Measure Σ[PT, N ] (= ΣPT,N ) of transverse momentum - multiplicity fluctuations of charged particles. 10  Intriguing results —maximum— for C+C and Si+Si collisions See in arXiv: , 2 March 2016

Recent data: rapid changes of K and π production properties signal 11  A shadow of Pb+Pb “Horn” structure in p+p data  The onset of deconfinement at √sNN ≈ 7.7 GeV

Strong interaction program of NA61/SHINE at SPS (done/planned) Strategy: system size and energy scan with improved sensitivity in a systematic search for the critical point. 12 NA61/SHINE “Hill” of fluctuations  Fluctuations and system size dependence in hadron collisions energy scan

Na61 installation arxiv:  See report at this conference by Sergey Morozov

Data taken by NA61/SHINE p+p collisions Data taken: 2009/10/11 Data taken at 20, 31, 40, 80, 158 GeV/c Results: Eur.Phys.J. C74 (2014) 3, 2794; CPOD 2014 arXiv: ; CERN-SPSC Be+Be collisions Data taken: 2011/12/13 Data taken at: 13, 19, 31, 40, 75, 150 A GeV/c Results: CERN-SPSC ; E. Kaptur, CPOD (2014) Hadrons produced in centrality selected classes  See also reports at this conference by E.Andronov and A.Seryakov p+Pb GeV/c and Ar+Sc collisions (in February – April 2015) --work is in progress Data taken at: 13, 19, 30, 40, 75, 150 A GeV/c Results: Status report to the proposal SPSC-P-330, Sept.29,

p+p collisions 15 Eur.Phys.J. C74 (2014) 3, 2794

p+p collisions Rapidity distributions and p T spectra of π− 16

17 p+p collisions

18 Be+Be collisions Event Selection and centrality CERN-SPSC ; E. Kaptur, CPOD (2014)  See morre in the report at this conference by Sergey Morozov

19 7 Be+ 9 Be 13, 19, 31 A GeV/c CERN-SPSC ; E. Kaptur, CPOD (2014)

20 Be+Be collisions Rapidity spectra CERN-SPSC ; E. Kaptur, CPOD (2014)

21 Transverse mass spectra p+p, Be+Be, Pb+Pb CERN-SPSC ; E. Kaptur, CPOD (2014)

22 Ratio of normalized m T spectra CERN-SPSC ; E. Kaptur, CPOD (2014) See more in the following talks by S.Morozov, E.Andronov, A.Seryakov…

Summary  Strong interaction program of NA61/SHINE at SPS is aimed at studies of the onset of deconfinement and search for the critical point of strongly interacting matter by means of investigation of fluctuations and system size dependences of various observables in hadron collisions energy scan  The first results in system size scan that started from the lightest systems π− spectra from p+p interactions at five beam momenta (20, 31, 40, 80, 158 GeV/c) and from 7 Be+ 9 30A, 40A, 75A, 150A GeV/c) are shown and compared.  The shape of transverse mass spectra in 7 Be+ 9 Be shows energy dependence that is different from p+p The results bring the indication on harderning of spectra with growing collision energy and system size. However, so far, no centrality dependence in Be+Be, no sign of any anomaly that can be attributed to Cp… Ar+Sc results will appear soon… 23

24 National Nuclear Research Center, Azerbaijan Faculty of Physics, University of Sofia, Bulgaria Ruder Boskovic Institute, Croatia LPNHE, University of Paris VI and VII, France Karlsruhe Institute of Technology, Germany Fachhochschule Frankfurt, Germany Institut für Kernphysik, Goethe-Universität, Germany Nuclear and Particle Physics Division, University of Athens, Greece Wigner RCP, Hungary Institute for Particle and Nuclear Studies (KEK), Japan University of Bergen, Norway Institute of Physics, Jan Kochanowski University, Poland National Center for Nuclear Research, Poland Institute of Physics, Jagiellonian University, Poland Institute of Physics, University of Silesia, Poland Faculty of Physics, University of Warsaw, Poland Department of Physics and Astronomy, University of Wroclaw, Poland Faculty of Physics, Warsaw University of Technology, Poland Institute for Nuclear Research, Russia Joint Institute for Nuclear Research, Russia St. Petersburg State University, Russia National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Russia University of Belgrade, Serbia ETH Zürich, Switzerland University of Bern, Switzerland University of Geneva, Switzerland University of Colorado Boulder, USA Los Alamos National Laboratory, USA Department of Physics and Astronomy, University of Pittsburgh, USA Fermilab, Neutrino Division, USA