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LHC Search for Right-handed Neutrinos in $Z^prime$ Models

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 Added by Chengcheng Han
 Publication date 2017
  fields
and research's language is English




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We consider right-handed neutrino pair production in generic $Z^prime$ models. We propose a new, model-independent analysis using final states containing a pair of same-sign muons. A key aspect of this analysis is the reconstruction of the RH neutrino mass, which leads to a significantly improved sensitivity. Within the $U(1)_{(B-L)_{3}}$ model, we find that at the HL-LHC it will be possible to probe RH neutrino masses in the range $0.2lesssim M_{N_R} lesssim 1.1,$TeV.



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We entertain the possibility that neutrino masses and dark matter (DM) originate from a common composite dark sector. A minimal effective theory can be constructed based on a dark $SU(3)_D$ interaction with three flavors of massless dark quarks; electroweak symmetry breaking gives masses to the dark quarks. By assigning a $mathbb Z_2$ charge to one flavor, a stable dark kaon can provide a good thermal relic DM candidate. We find that dark neutrons may be identified as right handed Dirac neutrinos. Some level of neutron-anti-neutron oscillation in the dark sector can then result in non-zero Majorana masses for light Standard Model neutrinos. A simple ultraviolet completion is presented, involving additional heavy $SU(3)_D$-charged particles with electroweak and lepton Yukawa couplings. At our benchmark point, there are dark pions that are much lighter than the Higgs and we expect spectacular collider signals arising from the UV framework. This includes the decay of the Higgs boson to $tau tau ell ell^{prime}$, where $ell$($ell$) can be any lepton, with displaced vertices. We discuss the observational signatures of this UV framework in dark matter searches and primordial gravitational wave experiments; the latter signature is potentially correlated with the $H to tau tau ell ell^{prime}$ decay.
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319 - J.W. van Holten 2015
In this lecture I review the most relevant modifications of the Standard Model of particle physics that result from inclusion of right-handed neutrinos and a new neutral gauge boson Z.
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