https://doi.org/10.1140/epjc/s10052-016-4450-9
Regular Article - Experimental Physics
Multiplicity and transverse momentum fluctuations in inelastic proton–proton interactions at the CERN Super Proton Synchrotron
1
National Nuclear Research Center, Baku, Azerbaijan
2
Faculty of Physics, University of Sofia, Sofia, Bulgaria
3
Ruđer Bošković Institute, Zagreb, Croatia
4
LPNHE, University of Paris VI and VII, Paris, France
5
Karlsruhe Institute of Technology, Karlsruhe, Germany
6
Fachhochschule Frankfurt, Frankfurt, Germany
7
University of Frankfurt, Frankfurt, Germany
8
University of Athens, Athens, Greece
9
Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Budapest, Hungary
10
Institute for Particle and Nuclear Studies, KEK, Tsukuba, Japan
11
University of Bergen, Bergen, Norway
12
Jan Kochanowski University in Kielce, Kielce, Poland
13
National Center for Nuclear Research, Warsaw, Poland
14
Jagiellonian University, Cracow, Poland
15
University of Silesia, Katowice, Poland
16
Faculty of Physics, University of Warsaw, Warsaw, Poland
17
University of Wrocław, Wrocław, Poland
18
Warsaw University of Technology, Warsaw, Poland
19
Institute for Nuclear Research, Moscow, Russia
20
Joint Institute for Nuclear Research, Dubna, Russia
21
St. Petersburg State University, St. Petersburg, Russia
22
University of Belgrade, Belgrade, Serbia
23
ETH Zürich, Zurich, Switzerland
24
University of Bern, Bern, Switzerland
25
University of Geneva, Geneva, Switzerland
* e-mail: tobiasz.czopowicz@cern.ch
Received:
16
October
2015
Accepted:
22
August
2016
Published online:
21
November
2016
Measurements of multiplicity and transverse momentum fluctuations of charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80, and 158 beam momentum. Results for the scaled variance of the multiplicity distribution and for three strongly intensive measures of multiplicity and transverse momentum fluctuations
,
and
are presented. For the first time the results on fluctuations are fully corrected for experimental biases. The results on multiplicity and transverse momentum fluctuations significantly deviate from expectations for the independent particle production. They also depend on charges of selected hadrons. The string-resonance Monte Carlo models Epos and Urqmd do not describe the data. The scaled variance of multiplicity fluctuations is significantly higher in inelastic p+p interactions than in central Pb+Pb collisions measured by NA49 at the same energy per nucleon. This is in qualitative disagreement with the predictions of the Wounded Nucleon Model. Within the statistical framework the enhanced multiplicity fluctuations in inelastic p+p interactions can be interpreted as due to event-by-event fluctuations of the fireball energy and/or volume.
© The Author(s), 2016