$e^{+}e^{-}$ pairs from a nuclear transition signaling an elusive light neutral boson

A. Krasznahorkay; F. W. N. de Boer; M. Csatlós; L. Csige; Z. Gácsi; J. Gulyás; M. Hunyadi; T. J. Ketel; J. van Klinken; A. Krasznahorkay Jr.; A. Vitéz

doi:10.1063/1.2140659

arXiv · hep-ex/0510054

$e^{+}e^{-}$ pairs from a nuclear transition signaling an elusive light neutral boson

A. Krasznahorkay·F. W. N. de Boer·M. Csatlós·L. Csige·Z. Gácsi·J. Gulyás·M. Hunyadi·T. J. Ketel·J. van Klinken·A. Krasznahorkay Jr.·A. Vitéz

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Abstract

Electron-positron pairs have been observed in the 10.95-MeV $0^-\to0^+$ decay in $^{16}$O. The branching ratio of the e$^+$e$^-$ pairs compared to the 3.84-MeV $0^-\to2^+$ $γ$ decay of the level is deduced to be $20(5)\times10^{-5}$. This magnetic monopole (M0) transition cannot proceed by $γ$-ray decay and is, to first order, forbidden for internal pair creation. However, the transition may also proceed by the emission of a light neutral $0^{-}$ or $1^{+}$ boson. Indeed, we do observe a sharp peak in the $e^{+}e^{-}$ angular correlation with all the characteristics belonging to the intermediate emission of such a boson with an invariant mass of 8.5(5) MeV/c$^2$. It may play a role in the current quest for light dark matter in the universe.

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A. Krasznahorkay, F. W. N. de Boer, M. Csatlós, L. Csige, Z. Gácsi, J. Gulyás, M. Hunyadi, T. J. Ketel, J. van Klinken, A. Krasznahorkay Jr., A. Vitéz. 2005-10-19. $e^{+}e^{-}$ pairs from a nuclear transition signaling an elusive light neutral boson. https://doi.org/10.1063/1.2140659

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