X17: Searching for New Physics in Nuclear Transitions

by Attila Krasznahorkay (CERN)

Monday 9 Mar 2020, 11:15 → 12:00 Europe/Zurich

BSP 626 (EPFL)

The study of the de-excitation of $^8$Be through the emission of $e^+e^-$ pairs found an anomaly in the angular correlation spectrum of the electrons [Phys. Rev. Lett. 116, 052501 (2016)]. One that can possibly be explained by the existence of a yet unknown (bosonic) particle. A new measurement, with a re-built experimental setup, studying the angular correlation of $e^+e^-$ pairs coming from the de-excitation of $^4$He provided a similar anomaly [arXiv:1910.10459 (nucl-ex)]. One that may be explained by the existence of the same $m_Xc^2 = 16.84 \pm 0.16 (stat) \pm 0.20 (syst)$ (X17) particle. The talk will review the experiments performed at the Institute for Nuclear Research (Atomki, http://www.atomki.hu/en/), describe the data analysis, and discuss the possible interpretations of the results.

X17_ Searching for New Physics in Nuclear Transitions 2020.03.09..pdf