Checking the ${}^8$Be anomaly with a two-arm electron positron pair spectrometer

Abstract

We have repeated the experiment performed recently by Krasznahorkay et al., (Phys. Rev. Lett. 116, 042501 (2016)), which may indicate a new particle called X17 in the literature. In order to get a reliable, and independent result, we used a different type of electron-positron pair spectrometer which have a more simple acceptance/efficiency as a function of the correlation angle, but the other conditions of the experiment were very similar to the published ones. We could confirm the presence of the anomaly measured at the E${}_x$=18.15 MeV resonance, and also confirm their absence at the E${}_x$=17.6 MeV resonance, and at E${}_p$= 800 keV off resonance energies.

arXiv commentInvited talk at the 52nd ISMD, Gyöngyös, Hungary, August 2023

References in corpus (6)

• Observation of Anomalous Internal Pair Creation in ${}^8$Be: A Possible Signature of a Light, Neutral Boson
• A new anomaly observed in ${}^4$He supports the existence of the hypothetical X17 particle
• New anomaly observed in ${}^{12}$C supports the existence and the vector character of the hypothetical X17 boson
• QED Meson Description of the X17 and Other Anomalous Particles
• A pair spectrometer for measuring multipolarities of energetic nuclear transitions
• Can a protophobic vector boson explain the ATOMKI anomaly?

Cited by in corpus (6)

• Search for a new 17 MeV resonance via $e^{+}{e}^{-}$ annihilation with the PADME Experiment
• On the Atomki nuclear anomaly after the MEG-II result
• Probing the ATOMKI X17 vector boson using Dalitz decays $V\to P{e}^{+}{e}^{-}$
• Radiative and Dalitz decays of ${\rm Y}(1S)$ in the light of the ATOMKI X17 anomaly
• Flavor specific chiral $U(1{)}_X$ framework for explaining the ATOMKI anomaly
• The X17 with Chiral Couplings