Heavy right-handed neutrino dark matter in left–right models

We propose a model with the left-handed and right-handed continuous Abelian gauge symmetry; U(1) L ×U(1) R . Then three right-handed neutrinos are naturally required to achieve U(1) R anomaly cancellations, while several mirror fermions are also needed to do U(1) L anomaly cancellations. Then we formulate the model, and discuss its testability of the new gauge interactions at collider physics such as the large hadron collider (LHC) and the international linear collider (ILC). In particular, we can investigate chiral structure of the interactions by the analysis of forward-backward asymmetry based on polarized beam at the ILC.

Section: Introductionsupporting

confidence: 68%

Left-handed and right-handed U(1) gauge symmetry

Nomura¹,

Okada²

2018

“…Though we focus on the minimal U (1) B−L and LRSM gauge groups in this paper, the basic arguments and main results could easily be generalized to other gauge groups at the TeV scale, such as the SU [49][50][51][52][53], and alternative left-right models with universal seesaw mechanism for the SM quarks and charged leptons [54][55][56][57][58][59][60][61][62][63] or with a stable right-handed neutrino (RHN) dark matter [64,65]. However, our results do not apply to situations where the extra U (1) groups emerge out of non-Abelian groups at an intermediate scale, since they will completely alter the ultraviolet (UV) behavior of the TeV scale U (1) gauge couplings.…”

Section: Introductionmentioning

confidence: 99%

Perturbativity constraints on U(1)B−L and left-right models and implications for heavy gauge boson searches

Chauhan¹,

Dev²,

Mohapatra

2019

Self Cite

We derive perturbativity constraints on beyond standard model scenarios with extra gauge groups, such as SU (2) or U (1), whose generators contribute to the electric charge, and show that there are both upper and lower limits on the additional gauge couplings, from the requirement that the couplings remain perturbative up to the grand unification theory (GUT) scale. This leads to stringent constraints on the masses of the corresponding gauge bosons and their collider phenomenology. We specifically focus on the models based on SU (2) L × U (1) I 3R × U (1) B−L and the left-right symmetric models based on SU (2) L × SU (2) R × U (1) B−L , and discuss the implications of the perturbativity constraints for new gauge boson searches at current and future colliders. In particular, we find that the stringent flavor constraints in the scalar sector of left-right model set a lower bound on the right-handed scale v R 10 TeV, if all the gauge and quartic couplings are to remain perturbative up to the GUT scale. This precludes the prospects of finding the Z R boson in the left-right model at the LHC, even in the high-luminosity phase, and leaves only a narrow window for the W R boson. A much broader allowed parameter space, with the right-handed scale v R up to 87 TeV, could be probed at the future 100 TeV collider.

“…From eq. (3.4), we find that the annihilation rate decreases with increasing DM mass, which leads to the unitarity bound of ∼ 20 TeV in our model [93]. Our goal in this subsection is to point out that in our model, there is a way to relax this generic bound without resorting to fine tuning of parameters (as required, e.g.…”

Section: Going Beyond the Unitarity Boundmentioning

confidence: 67%

“…There is also some dilution of DM relic density due to increase in entropy at the QCD phase transition point. Overall, it is possible to get a total dilution factor as big as d ∼ 10 6 , which can relax the unitarity bound for M N up to a PeV or so [93].…”

Section: Jhep11(2016)077mentioning

confidence: 99%

Naturally stable right-handed neutrino dark matter

Dev

Mohapatra

Zhang

2016

Self Cite

Abstract:We point out that a class of non-supersymmetric models based on the gauge group SU(3) C × SU(2) L × SU(2) R × U(1) Y L × U(1) Y R possesses an automatic, exact Z 2 symmetry under which the fermions in the SU(2) R × U(1) Y R sector (called R-sector) are odd and those in the SU(2) L ×U(1) Y L sector (called L-sector or the Standard Model sector) are even. This symmetry, which is different from the usual parity symmetry of the leftright symmetric models, persists in the lepton sector even after the gauge symmetry breaks down to SU(3) C × U(1) EM . This keeps the lightest right-handed neutrino naturally stable, thereby allowing it to play the role of dark matter (DM) in the Universe. There are several differences between the usual left-right models and the model presented here: (i) our model can have two versions, one which has no parity symmetry so that the couplings and masses in the L and R sectors are unrelated, and another which has parity symmetry so that couplings are related but with an extra Higgs doublet in each sector so that the fermion mass patterns are different; (ii) the R-sector fermions are chosen much heavier than the Lsector ones in both scenarios; and finally (iii) both light and heavy neutrinos are Majorana fermions with the light neutrino masses arising from a pure type-II seesaw mechanism. We discuss the DM relic density, direct and indirect detection prospects and associated collider signatures of the model. Comparing with current collider and direct detection constraints, we find a lower bound on the DM mass of order of 1 TeV. We also point out a way to relax the DM unitarity bound in our model for much larger DM masses by an entropy dilution mechanism. An additional feature of the model is that the DM can be made very long lived, if desired, by allowing for weak breaking of the above Z 2 symmetry. Our model also predicts the existence of long-lived colored particles which could be searched for at the LHC.