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Title: Long-Lived TeV-Scale Right-Handed Neutrino Production at the LHC in Gauged $$U(1)_X$$ Model

Abstract

A gauged $$U(1)_X$$ extension of the Standard Model is a simple and consistent framework to naturally incorporate three right-handed neutrinos (RHNs) for generating the observed light neutrino masses and mixing by the type-I seesaw mechanism. We examine the collider testability of the $$U(1)_X$$ model, both in its minimal form with the conventional charges, as well as with an alternative charge assignment, via the resonant production of the $$U(1)_X$$ gauge boson ($$Z^\prime$$) and its subsequent decay into a pair of RHNs. We first derive an updated upper limit on the new gauge coupling $$g_X$$ as a function of the $Z'$-boson mass from the latest LHC dilepton searches. Then we identify the maximum possible cross section for the RHN pair-production under these constraints. Finally, we investigate the possibility of having one of the RHNs long-lived, even for a TeV-scale mass. Employing the general parametrization for the light neutrino mass matrix to reproduce the observed neutrino oscillation data, we perform a parameter scan and find a simple formula for the maximum RHN lifetime as a function of the lightest neutrino mass eigenvalue ($$m_{\rm lightest}$$). We find that for $$m_{\rm lightest}\lesssim 10^{-5}$$ eV, one of the RHNs in the minimal $$U(1)_X$$ scenario can be long-lived with a displaced-vertex signature which can be searched for at the LHC and/or with a dedicated long-lived particle detector, such as MATHUSLA. In other words, once a long-lived RHN is observed, we can set an upper bound on the lightest neutrino mass in this model.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Osaka U.
  2. Fermilab
  3. Alabama U.
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1546016
Report Number(s):
arXiv:1906.04132; FERMILAB-PUB-19-268-T
1738966
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Journal Article
Journal Name:
TBD
Additional Journal Information:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Das, Arindam, Dev, P.S. Bhupal, and Okada, Nobuchika. Long-Lived TeV-Scale Right-Handed Neutrino Production at the LHC in Gauged $U(1)_X$ Model. United States: N. p., 2019. Web.
Das, Arindam, Dev, P.S. Bhupal, & Okada, Nobuchika. Long-Lived TeV-Scale Right-Handed Neutrino Production at the LHC in Gauged $U(1)_X$ Model. United States.
Das, Arindam, Dev, P.S. Bhupal, and Okada, Nobuchika. Mon . "Long-Lived TeV-Scale Right-Handed Neutrino Production at the LHC in Gauged $U(1)_X$ Model". United States. https://www.osti.gov/servlets/purl/1546016.
@article{osti_1546016,
title = {Long-Lived TeV-Scale Right-Handed Neutrino Production at the LHC in Gauged $U(1)_X$ Model},
author = {Das, Arindam and Dev, P.S. Bhupal and Okada, Nobuchika},
abstractNote = {A gauged $U(1)_X$ extension of the Standard Model is a simple and consistent framework to naturally incorporate three right-handed neutrinos (RHNs) for generating the observed light neutrino masses and mixing by the type-I seesaw mechanism. We examine the collider testability of the $U(1)_X$ model, both in its minimal form with the conventional charges, as well as with an alternative charge assignment, via the resonant production of the $U(1)_X$ gauge boson ($Z^\prime$) and its subsequent decay into a pair of RHNs. We first derive an updated upper limit on the new gauge coupling $g_X$ as a function of the $Z'$-boson mass from the latest LHC dilepton searches. Then we identify the maximum possible cross section for the RHN pair-production under these constraints. Finally, we investigate the possibility of having one of the RHNs long-lived, even for a TeV-scale mass. Employing the general parametrization for the light neutrino mass matrix to reproduce the observed neutrino oscillation data, we perform a parameter scan and find a simple formula for the maximum RHN lifetime as a function of the lightest neutrino mass eigenvalue ($m_{\rm lightest}$). We find that for $m_{\rm lightest}\lesssim 10^{-5}$ eV, one of the RHNs in the minimal $U(1)_X$ scenario can be long-lived with a displaced-vertex signature which can be searched for at the LHC and/or with a dedicated long-lived particle detector, such as MATHUSLA. In other words, once a long-lived RHN is observed, we can set an upper bound on the lightest neutrino mass in this model.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {6}
}