| Autor: |
Xilin Zhang, Gerald A. Miller |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
Physics Letters B, Vol 813, Iss , Pp 136061- (2021) |
| Druh dokumentu: |
article |
| ISSN: |
0370-2693 |
| DOI: |
10.1016/j.physletb.2021.136061 |
| Popis: |
In 2016, the ATOMKI collaboration announced [Phys. Rev. Lett. 116, 042501 (2016)] observing an unexpected enhancement of the e+-e−pair production signal in one of the Be8 nuclear transitions induced by an incident proton beam on a 7Li target. Many beyond-standard-model physics explanations have subsequently been proposed. One popular theory is that the anomaly is caused by the creation of a protophobic vector boson (X) with a mass around 17 MeV [e.g. Phys. Rev. Lett. 117, 071803 (2016)] in the nuclear transition. We study this hypothesis by deriving an isospin relation between photon and X couplings to nucleons. This allows us to find simple relations between protophobic X-production cross sections and those for measured photon production. The net result is that X production is dominated by direct transitions induced by E1X and L1X (transverse and longitudinal electric dipoles) and C1X (charge dipole) without going through any nuclear resonance (i.e. Bremsstrahlung radiation) with a smooth energy dependence that occurs for all proton beam energies above threshold. This contradicts the experimental observations and invalidates the protophobic vector boson explanation. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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Full Text from ScienceDirect