On the X(17) light-particle candidate observed in nuclear transitions

A. J. Krasznahorkay, M. Csatlós, L. Csige, D. Firak, J. Gulyás, Nagy, N. Sas, J. Timár, T. G. Tornyi, A. Krasznahorkay

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Recently, we observed an anomalous internal pair creation for the M1 transition depopulating the 18.15 MeV isoscalar 1 + state in 8 Be. The deviation from the theoretical prediction can be described by assuming the creation and subsequent decay of a new, light boson with a mass of 16.7 MeV/c 2 . In order to clarify the interpretation, we re-investigated the 8 Be anomaly with an improved and independent setup. We have confirmed the signal of the assumed X(17) particle and constrained its mass (m 0 c 2 = 17.01(16) MeV) and branching ratio compared to the γ-decay (B x = 6(1)× 10 6 ). We investigated also the high-energy (21 MeV) J π = 0 → 0 + transition in 4 He and got a consistent result for the X(17) particle.

Original languageEnglish
Pages (from-to)675-684
Number of pages10
JournalActa Physica Polonica B
Issue number3
Publication statusPublished - Mar 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Krasznahorkay, A. J., Csatlós, M., Csige, L., Firak, D., Gulyás, J., Nagy, Sas, N., Timár, J., Tornyi, T. G., & Krasznahorkay, A. (2019). On the X(17) light-particle candidate observed in nuclear transitions. Acta Physica Polonica B, 50(3), 675-684. https://doi.org/10.5506/APhysPolB.50.675