Analysis of the exclusive final state npe(+)e(-) in the quasi-free np reaction
Result description
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/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 -> 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.
Keywords
The result's identifiers
Result code in IS VaVaI
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Analysis of the exclusive final state npe(+)e(-) in the quasi-free np reaction
Original language description
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/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 -> 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.
Czech name
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Czech description
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Classification
Type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10304 - Nuclear physics
Result continuities
Project
GA13-06759S: Experimental Study of Hadrons in the Baryonic Medium
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
European Physical Journal A
ISSN
1434-6001
e-ISSN
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Volume of the periodical
53
Issue of the periodical within the volume
7
Country of publishing house
US - UNITED STATES
Number of pages
12
Pages from-to
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UT code for WoS article
000405609000001
EID of the result in the Scopus database
2-s2.0-85024371848
Basic information
Result type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
OECD FORD
Nuclear physics
Year of implementation
2017