https://doi.org/10.1140/epjc/s10052-015-3738-5
Regular Article - Experimental Physics
Critical fluctuations of the proton density in A+A collisions at 158A GeV
1
NIKHEF, Amsterdam, The Netherlands
2
Department of Physics, University of Athens, Athens, Greece
3
Eötvös Loránt University, Budapest, Hungary
4
Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, Hungary
5
MIT, Cambridge, MA, USA
6
H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Science, Cracow, Poland
7
GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
8
Joint Institute for Nuclear Research, Dubna, Russia
9
Fachbereich Physik der Universität, Frankfurt, Germany
10
CERN, Geneva, Switzerland
11
Institute of Physics, Jan Kochanowski University, Kielce, Poland
12
Fachbereich Physik der Universität, Marburg, Germany
13
Max-Planck-Institut für Physik, Munich, Germany
14
Institute of Particle and Nuclear Physics, Charles University, Prague, Czech Republic
15
Nuclear Physics Laboratory, University of Washington, Seattle, WA, USA
16
Atomic Physics Department, Sofia University St. Kliment Ohridski, Sofia, Bulgaria
17
Institute for Nuclear Research and Nuclear Energy, BAS, Sofia, Bulgaria
18
National Center for Nuclear Research, Warsaw, Poland
19
Institute for Experimental Physics, University of Warsaw, Warsaw, Poland
20
Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
21
Rudjer Boskovic Institute, Zagreb, Croatia
* e-mail: ndavis@phys.uoa.gr
Received:
6
May
2015
Accepted:
19
October
2015
Published online:
12
December
2015
We look for fluctuations expected for the QCD critical point using an intermittency analysis in the transverse momentum phase space of protons produced around midrapidity in the 12.5 % most central C+C, Si+Si and Pb+Pb collisions at the maximum SPS energy of 158A GeV. We find evidence of power-law fluctuations for the Si+Si data. The fitted power-law exponent
is consistent with the value expected for critical fluctuations. Power-law fluctuations had previously also been observed in low-mass
pairs in the same Si+Si collisions.
© The Author(s), 2015