REAL

Confirmation of the existence of the X17 particle

Firak, Daniel and Csige, Lóránt and Krasznahorkay, Attila and Csatlós, Margit and Tímár, János and Sas, Nándor and Nagy, Ádám and Koszta, M. and Szihalmi, B. (2020) Confirmation of the existence of the X17 particle. EPJ WEB OF CONFERENCES, 232 (04005). ISSN 2100-014X

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Abstract

In a 2016 paper, an anomaly in the internal pair creation on theM1transition depopulating the 18.15 MeV isoscalar 1+ state on 8Be was observed. This could be explained by the creation and subsequent decay of a new boson, with mass mXc2=16.70 MeV. Further experiments of the same transition with an improved and independent setup were performed, which constrained the mass of the X17 boson (mXc2) and its branching ratio relative to the γ-decay of the 8Be excited state (BX), to mXc2=17.01(16) MeV and BX=6(1)×10−6, respectively. Using the latter setup, the e+e− pairs depopulating the 21 MeV Jπ=0−→0+ transition in 4He were investigated and a resonance in the angular correlation of the pairs was observed, which could be explained by the same X17 particle, with mass mXc2=16.98±0.16(stat)±0.20(syst) MeV.

Item Type: Article
Subjects: Q Science / természettudomány > QC Physics / fizika > QC05 Physical nature of matter / részecskefizika
Depositing User: Dr. Lóránt Csige
Date Deposited: 28 Sep 2020 11:35
Last Modified: 28 Sep 2020 11:35
URI: http://real.mtak.hu/id/eprint/115062

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