Abstract
It is argued with the help of an illustrative model, that the inter species hierarchy among the fermion masses and the quark mixing angles can be accommodated naturally in the standard model with (approximate) flavor democracy provided there are three exactly massless neutrinos and four families of sequential quark-leptons with all members of the fourth family having roughly equal masses. The special problem of light neutrino masses (if any) and possible solutions are also discussed.
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Datta, A. Flavour democracy calls for the fourth generation. Pramana - J. Phys 40, L503–L509 (1993). https://doi.org/10.1007/BF02847136
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DOI: https://doi.org/10.1007/BF02847136