TY  - JOUR
AU  - HADES Collaboration (Agakishiev, G. et al
AU  - Diaz, J.
AU  - Gil, A.
PY  - 2010
DA  - 2010//
TI  - Origin of the low-mass electron pair excess in light nucleus-nucleus collisions
T2  - Phys. Lett. B
JO  - Physics Letters B
SP  - 118
EP  - 122
VL  - 690
IS  - 2
PB  - Elsevier Science Bv
KW  - Virtual bremsstrahlung
KW  - Dileptons
KW  - Nucleon-nucleon collisions
AB  - We report measurements of electron pair production in elementary p + p and d + p reactions at 1.25 GeV/mu with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n + p reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e- > 0.15 GeV/c(2) is about an order of magnitude larger in n + p reactions as compared to p + p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C + C reactions are compatible with a superposition of elementary n + p and p + p collisions, leaving little room for additional electron pair sources in such light collision systems.
SN  - 0370-2693
UR  - http://arxiv.org/abs/0910.5875
UR  - https://doi.org/10.1016/j.physletb.2010.05.010
DO  - 10.1016/j.physletb.2010.05.010
LA  - English
N1  - ISI:000279513800003
ID  - HADESCollaborationAgakishiev_etal2010
ER  -