https://doi.org/10.1140/epjc/s10052-022-10448-0
Regular Article - Theoretical Physics
Lepton collider probes for Majorana neutrino effective interactions
1
Instituto de Física de Mar del Plata (IFIMAR) CONICET, UNMDP, Funes 3350, 7600, Mar del Plata, Argentina
2
Instituto de Física, Facultad Ingeniería, Universidad de la República Julio Herrera y Reissig 565, 11300, Montevideo, Uruguay
3
Instituto de Física de Mar del Plata (IFIMAR) CONICET, UNMDP Departamento de Física, Universidad Nacional de Mar del Plata, Funes 3350, 7600, Mar del Plata, Argentina
4
Instituto de Física, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
Received:
10
January
2022
Accepted:
17
May
2022
Published online:
20
June
2022
The extension of the standard model with new high-scale weakly coupled physics involving right-handed neutrinos in an effective field theory framework (SMNEFT) allows for a systematic study of heavy neutrinos phenomenology in current and future experiments. We exploit the outstanding angular resolution in future lepton colliders to study the sensitivity of forward–backward asymmetries to discover the possible single production of heavy Majorana neutrinos via 
, followed by a purely leptonic decay 
or a semi-leptonic decay 
, for masses 
GeV. In this regime, we consider the N production and decays to be dominated by scalar and vectorial four-fermion 
single 
operators. This is an alternative analysis to searches using displaced vertices and fat jets, in a higher mass regime, where the N is short-lived but can be found by the angular distribution of its decay products. We find that a forward–backward asymmetry between the final muons in the pure leptonic decay mode provides a sensitivity up to 12
for 
GeV, for effective couplings 
and new physics scale 
TeV. In the case of the semi-leptonic decay, we can compare the final muon and higher 
jet flight directions, again finding up to 12 sensitivity to the effective signals.
© The Author(s) 2022
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