Neutrino masses and lepton mixing from A5 and CP

Abstract

We analyse in detail the phenomenological implications for lepton masses and mixing derived by the breaking of the discrete symmetries A 5 × CP into the subgroups Z 2 × CP in the neutrino sector and Z 5 in the charged lepton sector. We derive accurate analytic expressions for the sum of the neutrino masses Σ i m i as well as for the effective Majorana masses m β and m ββ under different hypotheses for the flavon vevs and compare them with the exact numerical results obtained from the diagonalization of the neutrino mass matrix. √ 3 or h r,2 < 0 ∧ f i > −h r,2 /2 √ 3. The sum rule is Σ = [m 1 + (21ϕ + 13)m 2 − 5(3ϕ + 2)m 3 ] 2 − (84ϕ + 52)m 1m2 + O(sin 2 θ 13 ), (3.84) PLANCK+BAO PLANCK ◼

Lepton flavor violation and neutrino masses from A5 and CP in the non-universal MSSM

“…Here we are interested in the phenomenology of Case II of [26], corresponding with G e = Z 5 . The neutrino spectrum for this scenario has been fully analyzed in [29]. A tuple of generators, Q of G e = Z 5 and (Z, X) of G ν = Z 2 ×CP, characterizing this realization is:…”

“…Each case is related to the addition of one extra particle to the SM spectrum: RH neutrinos, a scalar triplet or a fermion triplet, respectively. In the effective low-energy theory some of these constructions are equivalent to others (a detailed discussion about this can be found in Appendix C of [29]) so that we can reduce the discussion to just two cases: Mechanism I, consisting of the Weinberg operator and type II see-saw, and Mechanism II, which includes type I and III see-saw realizations. In the following, we specify the operators generating the neutrino masses for each mechanism.…”

“…In the following, we specify the operators generating the neutrino masses for each mechanism. The quantum numbers of the fields for each scenario are displayed in Table 1, where the nomenclature of [29] has been conserved.…”

“…As shown in [20][21][22][23][24], non-trivial flavor structures are unavoidable if the scale of transmission of SUSY breaking to the visible sector, Λ SUSY , is larger than the scale of breaking of the flavor symmetry, Λ f . The group A 5 combined with the so-called generalized CP symmetry has already been studied in different contexts [25][26][27][28][29]. Here, we aim to extend the work in [29] and analyze the phenomenological implications of considering A 5 and CP in a supersymmetric model.…”

“…The group A 5 combined with the so-called generalized CP symmetry has already been studied in different contexts [25][26][27][28][29]. Here, we aim to extend the work in [29] and analyze the phenomenological implications of considering A 5 and CP in a supersymmetric model. In these conditions, we will show that constraints from lepton flavor violation are very strong and, in many cases, they are able to explore supersymmetric masses well beyond the reach of direct searches at LHC [30,31].…”