Shedding light on X17: community report
Daniele S. M. Alves, Daniele Barducci, G. Cavoto, Luc Darmé, Luigi Delle Rose, L. Doria, Jonathan L. Feng, A. Frankenthal, A. Gasparian, E. Goudzovski, C. Gustavino, Shaaban Khalil, V. Kozhuharov, A. Krasznahorkay, T. Marchi, M. Meucci, Gerald A. Miller, Stefano Moretti, Marco Nardecchia, Enrico Nardi, H. Natal da Luz, Giovanni Organtini, A. Papa, A. Perrevoort, V. Petousis, G. Piperno, M. Raggi, F. Renga, P. Schwendimann, R.E. Sykora, Claudio Toni, P. Valente, C. Voena, Cheuk-Yin Wong, Xilin Zhang
Abstract
Abstract The workshop “Shedding light on X17” brings together scientists looking for the existence of a possible new light particle, often referred to as X17. This hypothetical particle can explain the resonant structure observed at $$\sim $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> </mml:math> 17 MeV in the invariant mass of electron-positron pairs, produced after excitation of nuclei such as $$^8\hbox {Be}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mn>8</mml:mn> </mml:msup> <mml:mtext>Be</mml:mtext> </mml:mrow> </mml:math> and $$^4\hbox {He}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mn>4</mml:mn> </mml:msup> <mml:mtext>He</mml:mtext> </mml:mrow> </mml:math> by means of proton beams at the Atomki Laboratory in Debrecen. The purpose of the workshop is to discuss implications of this anomaly, in particular theoretical interpretations as well as present and future experiments aiming at confirming the result and/or at providing experimental evidence for its interpretation.