The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.
Search for π 0 decays to invisible particles / Cortina Gil, E., Kleimenova, A., Minucci, E., Padolski, S., Petrov, P., Shaikhiev, A., Volpe, R., Numao, T., Velghe, B., Bryman, D., Fu, J., Husek, T., Jerhot, J., Kampf, K., Zamkovsky, M., Aliberti, R., Khoriauli, G., Kunze, J., Lomidze, D., Marchevski, R., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2021:2(2021), pp. 201-201. [10.1007/JHEP02(2021)201]
Search for π 0 decays to invisible particles
Bizzeti A.Funding Acquisition
;
2021
Abstract
The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ → π+X, where X is a particle escaping detection with mass in the range 0.110–0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.| File | Dimensione | Formato | |
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JHEP02(2021)201.pdf
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