The effective field theory of low scale see-saw at colliders Biekötter, Anke Rodríguez Chala, Mikael Spannowsky, Michael AB and MS acknowledge support by the UK Science and Technology Facilities Council (STFC) under grant ST/P001246/1. MC is supported by the Spanish MINECO under the Juan de la Cierva programme as well as by the Ministry of Science and Innovation under grant number FPA2016-78220-C3-3-P, and by the Junta de Andalucia grants FQM 101 and A-FQM-211-UGR18 (fondos FEDER). We study the Standard Model effective field theory (nu SMEFT) extended with operators involving right-handed neutrinos, focussing on the regime where the right-handed neutrinos decay promptly on collider scales to a photon and a Standard Model neutrino. This scenario arises naturally for right-handed neutrinos with masses of the order m(N) similar to 0.1 ... 10GeV. We limit the relevant dimension-six operator coefficients using LEP and LHC searches with photons and missing energy in the final state as well as pion and tau decays. While bounds on new physics contributions are generally in the TeV scale for order one operator coefficients, some coefficients, however, remain very poorly constrained or even entirely evade bounds from current data. Consequently, we identify such weakly constrained scenarios and propose new searches for rare top and tau decays involving photons to probe potential new physics in the nu SMEFT parameter space. Our analysis highlights the importance of performing dedicated searches for new rare tau and top decays. 2020-11-11T10:55:05Z 2020-11-11T10:55:05Z 2020-08-14 journal article Biekötter, A., Chala, M. & Spannowsky, M. The effective field theory of low scale see-saw at colliders. Eur. Phys. J. C 80, 743 (2020). [https://doi.org/10.1140/epjc/s10052-020-8339-2] http://hdl.handle.net/10481/64200 10.1140/epjc/s10052-020-8339-2 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España Springer Nature