https://doi.org/10.1051/epjconf/202024101013
Exploring time like tranistions in pp, πp and AA reactions with HADES
1 LIP-Laboratório de Instrumentação e Física Experimental de Partículas , 3004-516 Coimbra, Portugal
2 Institute of Nuclear Physics, Polish Academy of Sciences, , 31342 Kraków, Poland
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 E62, Technische Universität München, 85748 Garching, Germany
11 II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392 Giessen, Germany
12 Forschungszentrum Juelich, 52428 Juelich, Germany
13 Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow, Russia
14 Institute of Theoretical and Experimental Physics, 117218 Moscow, Russia
15 National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409 Moscow, Russia
16 Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, Université Paris-Saclay, F-91406 Orsay Cedex, France
17 Nuclear Physics Institute, The Czech Academy of Sciences, 25068 Rez Czech Republic
18 Uniwersytet Warszawski - Instytut Fizyki Do´swiadczalnej, 02-093 Warszawa, Poland
19 Bergische Universität Wuppertal, 42119 Wuppertal, Germany
a also at Coimbra Polytechnic - ISEC, Coimbra, Portugal
b also at Technische Universität Dresden, 01062 Dresden, Germany
Published online: 22 September 2020
Radiative transition of an excited baryon to a nucleon with emission of a virtual massive photon converting to dielectron pair (Dalitz decays) provides important information about baryon-photon coupling at low q2 in timelike region. A prominent enhancement in the respective electromagnetic transition Form Factors (etFF) at q2 near vector mesons ρ/ω poles has been predicted by various calculations reflecting strong baryon-vector meson couplings. The understanding of these couplings is also of primary importance for the interpretation of the emissivity of QCD matter studied in heavy ion collisions via dilepton emission. Dedicated measurements of baryon Dalitz decays in proton-proton and pion-proton scattering with HADES detector at GSI/FAIR are presented and discussed. The relevance of these studies for the interpretation of results obtained from heavy ion reactions is elucidated on the example of the HADES results.
© The Authors, published by EDP Sciences, 2020
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