Publication
Analysis of the exclusive final state npe$^+$e$^-$ in quasi-free np reaction
| dc.contributor.author | HADES collaboration (117 authors) | |
| dc.contributor.author | Blanco, A. | |
| dc.contributor.author | Bordalo, P. | |
| dc.contributor.author | Fonte, P. | |
| dc.contributor.author | Franco, C. | |
| dc.contributor.author | Lopes, L. | |
| dc.contributor.author | Mangiarotti, A. | |
| dc.contributor.author | Ramos, S. | |
| dc.contributor.author | Silva, L. | |
| dc.date.accessioned | 2019-02-04T12:38:29Z | |
| dc.date.available | 2019-02-04T12:38:29Z | |
| dc.date.issued | 2017-07-18 | |
| dc.date.updated | 2019-02-04T12:38:29Z | |
| dc.description.abstract | We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25GeV/u impinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of $e^{+}e^{-}$ pairs above the $\pi^{0}$ mass in the exclusive channel $dp \rightarrow npe^{+}e^{-}(p_{spect})$ as compared to the exclusive channel $ ppe^{+}e^{-}$ measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double- $\Delta$ excitation combined with intermediate $\rho$ -meson production. Differential cross sections as a function of the $e^{+}e^{-}$ invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical sides. | |
| dc.description.version | Peer Reviewed | |
| dc.identifier | Eur.Phys.J. A53 (2017) 149; DOI 10.1140/epja/i2017-12341-3 | |
| dc.identifier.uri | http://dx.doi.org/10.1140/epja/i2017-12341-3 | |
| dc.identifier.uri | http://hdl.handle.net/10400.26/27315 | |
| dc.language.iso | eng | |
| dc.title | Analysis of the exclusive final state npe$^+$e$^-$ in quasi-free np reaction | |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| rcaap.rights | openAccess | pt |
| rcaap.type | article |