Abstract
Motivated by the recent search for a Higgs-Portal Scalar decaying inside the MicroBooNE detector, we demonstrate that the same search can be used to constrain Heavy Neutral Leptons. These are gauge-singlet fermions that interact with the Standard Model by mixing with neutrinos only and could be related to the origin of neutrino masses. By recasting the results of the MicroBooNE Collaboration's analysis, we show that, for a Heavy Neutral Lepton that mixes predominantly with muon-flavored neutrinos, previously unexplored parameter space can be excluded for masses between 30 and 150 MeV. Additionally, we make our Monte Carlo tools publicly available.
Highlights
The revelation that neutrinos are massive particles has spurred great interest in their properties
Several seesaw models postulate the existence of new leptons, neutral under the standard model gauge group—the heavy neutral leptons (HNLs)
We show that current data from the MicroBooNE experiment [12] can constrain the existence of HNLs in an unexplored region of parameter space for masses between ∼20–200 MeV
Summary
The revelation that neutrinos are massive particles has spurred great interest in their properties. HNLs are a common, generic outcome of many seesaw models, there is no clear indication of what are their masses, neither how large are their mixings with active neutrino flavors. The large angle between the NuMI absorber and the detector relative to the NuMI beam direction can be used to further mitigate backgrounds These two features allows for a competitive experimental sensitivity to Higgs portal scalars (HPS). MicroBooNE exploits several kinematical features of the eþe− pair to increase the signal-to-background ratio These include the opening angle between the electrons and their angles with respect to the line connecting the absorber and the detector center, and the number of hits and length of the reconstructed objects in the LArTPC. The very same data used to constrain HPS can be readily used to put a competitive constraint on as-yet unexplored values of HNL masses and mixings
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
