https://doi.org/10.1140/epja/i2008-10746-7
Regular Article - Experimental Physics
Measurement of charged pions in 12C + 12C collisions at 1 A GeV and 2 A GeV with HADES
1
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, 95125, Catania, Italy
2
LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516, Coimbra, Portugal
3
Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059, Kraków, Poland
4
GSI Helmholtzzentrum für Schwerionenforschung, 64291, Darmstadt, Germany
5
Institut für Strahlenphysik, Forschungszentrum Dresden-Rossendorf, 01314, Dresden, Germany
6
Joint Institute of Nuclear Research, 141980, Dubna, Russia
7
Institut für Kernphysik, Johann Wolfgang Goethe-Universität, 60438, Frankfurt, Germany
8
II. Physikalisches Institut, Justus Liebig Universität Giessen, 35392, Giessen, Germany
9
Istituto Nazionale di Fisica Nucleare, Sezione di Milano, 20133, Milano, Italy
10
Institute for Nuclear Research, Russian Academy of Science, 117312, Moscow, Russia
11
Physik Department E12, Technische Universität München, 85748, München, Germany
12
Department of Physics, University of Cyprus, 1678, Nicosia, Cyprus
13
Institut de Physique Nucléaire, CNRS/IN2P3 - Université Paris Sud, F-91406, Orsay Cedex, France
14
Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068, Rez, Czech Republic
15
Departamento de Física de Partículas, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain
16
Instituto de Física Corpuscular, Universidad de Valencia-CSIC, 46971, Valencia, Spain
17
Panstwowa Wyzsza Szkola Zawodowa, 33-300, Nowy Sacz, Poland
18
Dipartimento di Fisica e Astronomia, Università di Catania, 9125, Catania, Italy
19
Universidade de Coimbra, Coimbra, Portugal
20
ISEC Coimbra, Coimbra, Portugal
21
Dipartimento di Fisica, Università di Milano, 20133, Milano, Italy
* e-mail: mousa@ucy.ac.cy
Received:
11
August
2008
Revised:
23
January
2009
Accepted:
4
March
2009
Published online:
4
April
2009
We present the results of a study of charged-pion production in 12C + 12C collisions at incident beam energies of 1A GeV and 2A GeV using the HADES spectrometer at GSI. The main emphasis of the HADES program is on the dielectron signal from the early phase of the collision. Here, however, we discuss the data with respect to the emission of charged hadrons, specifically the production of mesons, which are related to neutral pions representing a dominant contribution to the dielectron yield. We have performed the first large-angular-range measurement of the distribution of
mesons for the 12C + 12C collision system covering a fairly large rapidity interval. The pion yields, transverse-mass and angular distributions are compared with calculations done within a transport model, as well as with existing data from other experiments. The anisotropy of pion production is systematically analyzed.
PACS: 25.75.-q Relativistic heavy-ion collisions – / 25.75.Dw Particle and resonance production –
© SIF, Springer-Verlag Berlin Heidelberg, 2009