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The effective field theory of low scale see-saw at colliders

Biekötter, Anke; Chala, Mikael; Spannowsky, Michael

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Anke Biekötter

Mikael Chala


We study the Standard Model effective field theory (νSMEFT) 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 mN∼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 νSMEFT parameter space. Our analysis highlights the importance of performing dedicated searches for new rare tau and top decays.


Biekötter, A., Chala, M., & Spannowsky, M. (2020). The effective field theory of low scale see-saw at colliders. The European Physical Journal C, 80(8), Article 743.

Journal Article Type Article
Acceptance Date Aug 9, 2020
Online Publication Date Aug 14, 2020
Publication Date 2020-08
Deposit Date Aug 18, 2020
Publicly Available Date Aug 18, 2020
Journal European Physical Journal C: Particles and Fields
Print ISSN 1434-6044
Electronic ISSN 1434-6052
Publisher SpringerOpen
Peer Reviewed Peer Reviewed
Volume 80
Issue 8
Article Number 743


Published Journal Article (780 Kb)

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