Abstract
The KOTO experiment recently reported four candidate events in the signal region of KL→π0ννą search, where the standard model only expects 0.10±0.02 events. If confirmed, this requires physics beyond the standard model to enhance the signal. We examine various new physics interpretations of the result including these: (1) heavy new physics boosting the standard model signal, (2) reinterpretation of "ννą" as a new light long-lived particle, or (3) reinterpretation of the whole signal as the production of a new light long-lived particle at the fixed target. We study the above explanations in the context of a generalized new physics Grossman-Nir bound coming from the K+→π+ννą decay, bounded by data from the E949 and the NA62 experiments.
Original language | English |
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Article number | 071801 |
Number of pages | 6 |
Journal | Physical Review Letters |
Volume | 124 |
Issue number | 7 |
DOIs | |
Publication status | Published - 19 Feb 2020 |
Funding
We would like to thank Yossi Nir for valuable discussions and for Jure Zupan for comments on the manuscript. T. K. is supported by the Israel Science Foundation (Grant No. 720/15), by the United-States-Israel Binational Science Foundation (BSF) (Grant No. 2014397), by the ICORE Program of the Israel Planning and Budgeting Committee (Grant No. 1937/12), and by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant No. 19K14706. G. P. is supported by grants from the BSF, ERC, ISF, Minerva Foundation, and the Segre Research Award. K. T. and T. O. are supported by the US Department of Energy Grant No. DE-SC0010102. K. T. is supported by his startup fund at Florida State University (Project No. 084011-550-042584).
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy