Search for a feebly interacting particle X in the decay K+π+X


A search for the K+π+X decay, where X is a long-lived feebly interacting particle, is performed through an interpretation of the K+\( {\pi}^{+}\nu \overline{\nu} \) analysis of data collected in 2017 by the NA62 experiment at CERN. Two ranges of X masses, 0–110 MeV/c2 and 154–260 MeV/c2, and lifetimes above 100 ps are considered. The limits set on the branching ratio, BR(K+π+X), are competitive with previously reported searches in the first mass range, and improve on current limits in the second mass range by more than an order of magnitude.

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Correspondence to R. Volpe or J. Swallow.

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ArXiv ePrint: 2011.11329

Deceased (A. Zinchenko, A. Ostankov, V. Semenov, F. Hahn)

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The NA62 collaboration., Cortina Gil, E., Kleimenova, A. et al. Search for a feebly interacting particle X in the decay K+π+X. J. High Energ. Phys. 2021, 58 (2021).

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  • Beyond Standard Model
  • Exotics
  • Fixed target experiments