An outside analyst considers the data of the Hungarian researchers who proposed a new fundamental 17 MeV boson dubbed X17 and finds that their data is not consistent with the X17 explanation.
[Submitted on 25 Aug 2020]
Can a protophobic vector boson explain the ATOMKI anomaly?
In 2016, the ATOMKI collaboration announced [PRL 116, 042501 (2016)] observing an unexpected enhancement of thepair production signal in one of the Be nuclear transitions induced by an incident proton beam on a Li 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 ( ) with a mass around 17 MeV [e.g., PRL 117, 071803 (2016)] in the nuclear transition. We study this hypothesis by deriving an isospin relation between photon and couplings to nucleons. This allows us to find simple relations between protophobic -production cross sections and those for measured photon production. The net result is that production is dominated by a direct transition 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.