Loading...
Please wait, while we are loading the content...
Similar Documents
Lawrence Berkeley National Laboratory Recent Work Title Textures for atmospheric and solar neutrino oscillations Permalink
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hall, Lawrence J. Strumia |
| Copyright Year | 2013 |
| Abstract | In theories with three light neutrinos, a complete list of five zeroth-order textures for lepton mass matrices is found, which naturally yield: me,J.L = 0, mT =f. 0, ~m~ = 0, together with eeT = 0, eJ.LT ~ 1. These textures provide suitable starting points for constructing theories which account for both atmospheric and solar neutrino fluxes. Using flavor symmetries, two schemes for such lepton masses are found, and example constructions exhibited. *This work was supported in part by t~e U.S. Department of Energy under Contracts DE-AC0376SF00098, in part by the National Science Foundation under grant PHY-95-14797 and in part by the TMR Network under the EEC Contract No. ERBFMRXCT960090. 1 The Super-Kamiokande Collaboration has provided strong evidence that atmospheric vJ..t are depleted as they traverse the Earth [1, 2]. For example, the up/down event ratio shows a 6ostatistical significance, and could only be explained by some systematic effect an order of magnitude larger than those already considered. With two flavor vJ..t --+ V-r oscillations, the mixing angle is large, sin2 20 > 0.82, and ~m~TM is within a factor of three of 1.5 x 10-3 eV2 at the 90% C.L. [2]. In this letter we study lepton masses in theories with three light neutrinos. With the assumptions given below, we find a complete list of five zeroth-order textures, which can account both for this atmospheric data and for the presence of solar neutrino oscillations at some frequency ~m~ « ~m~TM· Requiring the textures to follow from symmetries, we are able to find only two zeroth-order schemes for the light lepton mass matrices which give both the observed atmospheric and solar neutrino fluxes. 2 Both 'charged and neutral lepton mass matrices involve small dimensionless parameters: me/m-r « mJ..t/m-r « 1 and ~m~/ ~m~TM « 1. In the flavor basis, the lepton mass matrices, lLmEfR and v[ ffiLLVL, can be written as a perturbation series in a set of small parameters c: ( (0) (1) ( ) ) ffiE = V AE + AE € + ... (1) 2 -~('(0) \(1)() ) ffiLL M "v + "v t + ··· (2) where v is the electroweak symmetry breaking scale and M is some new large mass scale, so that the )..(i) are dimensionless contributions at ith order in perturbation theory. The matrices)..~) and )..~0 ) have entries which are either zero or of order unity, and the possible forms for these matrices, which we call zeroth-order textures, are the subject of this letter. 1 Diagonalization of mE and mLL gives both the lepton mass eigenvalues and the leptonic mixing matrix V, defined by the charged current interaction DVT 11-tf Ww Ignoring phases, which are irrelevant for our purposes, we define the three Euler angles by V = V:tVv = R23(()23)R13(013)R12(B12)· The rotation matrices Ve,v, which diagonalize mE,LL, are the same functions of the angles OE,vij as V is of ()ij· We require that the diagonalization of >..~!v leads to zeroth-order eigenvalues m (O) m(O) 0 E1E2(3) (4) (5) 10ur classification of textures does not assume any flavor symmetry. However, perturbation series of the type (I) and (2) could result from a flavor symmetry which defines the flavor basis, allows the terms A~)v' and leads to higher order corrections as a power series in the small flavor symmetry breaking ' parameters E. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://cloudfront.escholarship.org/dist/prd/content/qt3fg623k4/qt3fg623k4.pdf?t=p2bgd9 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
