scholarly journals Neutrino mass, mixing and muon g − 2 explanation in $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ extension of left-right theory

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Chayan Majumdar ◽  
Sudhanwa Patra ◽  
Prativa Pritimita ◽  
Supriya Senapati ◽  
Urjit A. Yajnik

Abstract We consider a gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ extension of the left-right symmetric theory in order to simultaneously explain neutrino mass, mixing and the muon anomalous magnetic moment. We get sizeable contribution from the interaction of the new light gauge boson Zμτ of the $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ symmetry with muons which can individually satisfy the current bounds on muon (g − 2) anomaly (∆aμ). The other positive contributions to ∆aμ come from the interactions of singly charged gauge bosons WL, WR with heavy neutral fermions and that of neutral CP-even scalars with muons. The interaction of WL with heavy neutrino is facilitated by inverse seesaw mechanism which allows large light-heavy neutrino mixing and explains neutrino mass in our model. CP-even scalars with mass around few hundreds GeV can also satisfy the entire current muon anomaly bound. The results show that the model gives a small but non-negligible contribution to ∆aμ thereby eliminating the entire deviation in theoretical prediction and experimental result of muon (g − 2) anomaly. We have briefly presented a comparative study for symmetric and asymmetric left-right symmetric model in context of various contribution to ∆aμ. We also discuss how the generation of neutrino mass is affected when left-right symmetry breaks down to Standard Model symmetry via various choices of scalars.

2018 ◽  
Vol 33 (32) ◽  
pp. 1850201
Author(s):  
O. M. Boyarkin ◽  
G. G. Boyarkina ◽  
D. S. Vasileuskaya

Within the left–right symmetric model (LRM) the [Formula: see text] boson decay into the channel [Formula: see text] are investigated. The branching ratios of this decay is found in the third order of the perturbation theory. The obtained expression does not equal to zero only at the existence of the neutrino mixings. This means that from the point of view of the LRM, the nonconservations of the neutral and the charged lepton flavors have the same nature. As a result, the elucidation of the decays [Formula: see text] [Formula: see text] could provide data concerned the neutrino sector structure of the LRM. The neutrino sector parameters which could be measured in that case are as follows: (i) difference of the heavy neutrino masses; (ii) heavy–heavy neutrino mixing; (iii) heavy–light neutrino mixing.


2013 ◽  
Vol 28 (11) ◽  
pp. 1350032 ◽  
Author(s):  
JOYDEEP CHAKRABORTTY ◽  
MOUMITA DAS ◽  
SUBHENDRA MOHANTY

The vacuum stability condition of the Standard Model (SM) Higgs potential with mass in the range of 124–127 GeV puts an upper bound on the Dirac mass of the neutrinos. We study this constraint with the right-handed neutrino masses up to TeV scale. The heavy neutrinos contribute to ΔL = 2 processes like neutrinoless double beta decay and same-sign-dilepton (SSD) production in the colliders. The vacuum stability criterion also restricts the light-heavy neutrino mixing and constrains the branching ratio (BR) of lepton flavor-violating process, like μ→eγ mediated by the heavy neutrinos. We show that neutrinoless double beta decay with a lifetime ~1025 years can be observed if the lightest heavy neutrino mass is <4.5 TeV. We show that the vacuum stability condition and the experimental bound on μ→e γ together put a constrain on heavy neutrino mass MR>3.3 TeV. Finally we show that the observation of SSDs associated with jets at the LHC needs much larger luminosity than available at present. We have estimated the possible maximum cross-section for this process at the LHC and show that with an integrated luminosity 100 fb-1 it may be possible to observe the SSD signals as long as MR < 400 GeV.


2010 ◽  
Vol 25 (23) ◽  
pp. 4325-4337 ◽  
Author(s):  
S. T. PETCOV

The phenomenology of 3-neutrino mixing and of the related Dirac and Majorana leptonic CP violation is reviewed. The leptogenesis scenario of generation of the baryon asymmetry of the Universe, which is based on the see-saw mechanism of neutrino mass generation, is considered. The results showing that the CP violation necessary for the generation of the baryon asymmetry of the Universe in leptogenesis can be due exclusively to the Dirac and/or Majorana CP-violating phase(s) in the neutrino mixing matrix U are briefly reviewed.


2005 ◽  
Vol 20 (34) ◽  
pp. 2601-2605 ◽  
Author(s):  
ERNEST MA

In a new application of the discrete non-Abelian symmetry A4 using the canonical seesaw mechanism, a three-parameter form of the neutrino mass matrix is derived. It predicts the following mixing angles for neutrino oscillations: θ13=0, sin 2θ23=1/2, and sin 2θ12 close, but not exactly equal to 1/3, in one natural symmetry limit.


2020 ◽  
Vol 35 (09) ◽  
pp. 2050053
Author(s):  
Goran Senjanović ◽  
Vladimir Tello

In the LHC era the issue of the origin and nature of neutrino mass has attained a new meaning and a renewed importance. The growing success of the Higgs–Weinberg mechanism behind the charged fermion masses paves the way for answering the question of neutrino mass. We have shown recently how the spontaneous breaking of parity in the context of the minimal left–right symmetric model allows to probe the origin of neutrino mass in complete analogy with the charged fermions masses in the Standard Model. We revisit here this issue and fill in the gaps left in our previous work. In particular we discuss a number of different mathematical approaches to the problem of disentangling the seesaw mechanism and show how a unique analytical solution emerges. Most important, we give all the possible expressions for the neutrino Dirac mass matrix for general values of light and heavy neutrino mass matrices. In practical terms what is achieved is an untangling of the seesaw mechanism with clear and precise predictions testable at hadron colliders such as LHC.


2002 ◽  
Vol 17 (19) ◽  
pp. 2519-2533 ◽  
Author(s):  
TERUYUKI KITABAYASHI ◽  
MASAYAKI YASUÈ

The Zee model, which employs the standard Higgs scalar (ϕ) with its duplicate (ϕ ′) and a singly charged scalar (h+), can utilize two global symmetries associated with the conservation of the numbers of ϕ and ϕ′, Nϕ, ϕ′, where Nϕ + Nϕ′ coincides with the hypercharge while Nϕ - Nϕ′ (≡ X) is a new conserved charge, which is identical to Le - Lμ - Lτ for the left-handed leptons. Charged leptons turn out to have e–μ and e–τ mixing masses, which are found to be crucial for the large solar neutrino mixing. In an extended version of the Zee model with an extra triplet Higgs scalar (s), neutrino oscillations are described by three steps: (1) the maximal atmospheric mixing is induced by democratic mass terms supplied by s with X = 2 that can initiate the type II seesaw mechanism for the smallness of these masses; (2) the maximal solar neutrino mixing is triggered by the creation of radiative masses by h+ with X=0; (3) the large solar neutrino mixing is finally induced by a νμ - ντ mixing arising from the rotation of the radiative mass terms as a result of the diagonalization that converts e–μ and e–τ mixing masses into the electron mass.


2009 ◽  
Vol 24 (27) ◽  
pp. 2161-2165 ◽  
Author(s):  
ERNEST MA

If neutrino masses are obtained via the canonical seesaw mechanism, based on an underlying 2 ×2 mass matrix, unitarity violation of the neutrino mixing matrix is unavoidable, but its effect is extremely small. On the other hand, in the inverse (and linear) seesaw mechanisms, based on an underlying 3 ×3 mass matrix, it can be significant and possibly observable. This 3 ×3 matrix is examined in more detail, and a new variation (the lopsided seesaw) is proposed which has features of both mechanisms. A concrete example based on U (1)N is discussed.


1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.


2021 ◽  
pp. 136609
Author(s):  
Sanjoy Mandal ◽  
Nicolás Rojas ◽  
Rahul Srivastava ◽  
José W.F. Valle

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