Collider phenomenology of heavy neutrinos

dc.contributorHarms, B.
dc.contributorRumerio, Paolo
dc.contributorToale, Patrick A.
dc.contributorSchad, Rainer
dc.contributorAgashe, Kaustubh
dc.contributor.advisorOkada, Nobuchika
dc.contributor.authorDas, Arindam
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractThe existence of the neutrino mass has been established by the neutrino oscillation experiments. The so-called seesaw extension of the Standard Model is probably the simplest idea to naturally explain the existence of tiny neutrino mass through the lepton number violating Majorana mass term. There is another alternative way, commonly known as the inverse seesaw mechanism, where the small neutrino mass is obtained by the tiny lepton number violating parameters. In this work we investigate the signatures of such heavy neutrinos, having mass in the Electroweak scale at the high energy colliders. Based on a simple realization of inverse seesaw model we fix the model parameters to reproduce the neutrino oscillation data and to satisfy the other experimental constraints. We assume two flavor structures of the model and the different types of hierarchical light neutrino mass spectra. For completeness we consider the general parameterization for the model parameters by introducing an arbitrary orthogonal matrix and the nonzero Dirac and Majorana phases. Due to the smallness of the lepton number violating parameter this model can manifest the trilepton plus missing energy at the Large Hadron Collider(LHC). Using the recent LHC results for anomalous production of the multilepton events at $8$ TeV with a luminosity of $19.5$ fb$^{-1}$, we derive the direct upper bounds on the light-heavy neutrino mixing parameter as a function of the heavy neutrino mass. Using a variety of initial states such as quark-quark, quark-gluon and gluon-gluon as well as photon mediated processes for the Majorana heavy neutrinos we obtain direct upper bounds on the light-heavy neutrino mixing angles from the current LHC data at $8$ TeV. For the pseudo-Dirac heavy neutrinos produced from the various initial states using the recent anomalous multilepton search by the LHC at $8$ TeV with $19.5$ fb$^{-1}$ luminosity, we obtain upper bounds on the mixing angles.en_US
dc.format.extent126 p.
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectParticle physics
dc.titleCollider phenomenology of heavy neutrinosen_US
dc.typetext of Alabama. Department of Physics and Astronomy University of Alabama
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