https://doi.org/10.1140/epja/i2014-14082-1
Regular Article - Experimental Physics
Baryon resonance production and dielectron decays in proton-proton collisions at 3.5 GeV
1
INFN, 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 GmbH, 64291, Darmstadt, Germany
5
Technische Universität Darmstadt, 64289, Darmstadt, Germany
6
Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden, Germany
7
Joint Institute of Nuclear Research, 141980, Dubna, Russia
8
Institut für Kernphysik, Goethe-Universität, 60438, Frankfurt, Germany
9
Excellence Cluster “Origin and Structure of the Universe”, 85748, Garching, Germany
10
Physik Department E12, Technische Universität München, 85748, Garching, Germany
11
II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392, Giessen, Germany
12
INFN, Sezione di Milano, 20133, Milano, Italy
13
Institute for Nuclear Research, Russian Academy of Science, 117312, Moscow, Russia
14
Institute of Theoretical and Experimental Physics, 117218, Moscow, Russia
15
Department of Physics, University of Cyprus, 1678, Nicosia, Cyprus
16
Institut de Physique Nucléaire (UMR 8608), CNRS/IN2P3, Université Paris Sud, F-91406, Orsay Cedex, France
17
Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068, Rez, Czech Republic
18
LabCAF. F. Física, Univ. de Santiago de Compostela, 15706, Santiago de Compostela, Spain
* e-mail: witold.przygoda@uj.edu.pl
Received:
3
January
2014
Revised:
12
March
2014
Accepted:
25
March
2014
Published online:
9
May
2014
We report on baryon resonance production and decay in proton-proton collisions at a kinetic energy of 3.5 GeV based on data measured with HADES. The exclusive channels and
as well as
are studied simultaneously for the first time. The invariant masses and angular distributions of the pion-nucleon systems were studied and compared to simulations based on a resonance model ansatz assuming saturation of the pion production by an incoherent sum of baryonic resonances (R with masses < 2 GeV/c2. A very good description of the one-pion production is achieved allowing for an estimate of individual baryon resonance production cross sections which are used as input to calculate the dielectron yields from
decays. Two models of the resonance decays into dielectrons are examined assuming a point-like
coupling and the dominance of the
meson. The results of model calculations are compared to data from the exclusive
channel by means of the dielectron and
invariant mass distributions.
© SIF, Springer-Verlag Berlin Heidelberg, 2014