Unique mass texture for quarks and leptons

Abstract

Texture specific quark mass matrices which are hermitian and hierarchical are examined in detail . In the case of texture 6 zeros matrices, out of sixteen possibilities examined by us, none is able to fit the low energy data (LED), for example, |V us |= 0.2196 ± 0.0023, |V cb |= 0.0395 ± 0.0017, | V ub V cb |= 0.08 ± 0.02, |V td | lies in the range 0.004 -0.013 (PDG). Similarly none of the 32 texture 5 zeros mass matrices considered is able to reproduce LED. In particular, the latest data from LEP regarding | V ub V cb | (= 0.093 ± 0.016) rules out all of them. In the texture 4 zeros case, we find that there is a unique texture structure for U and D mass matrices which is able to fit the data. PACS number(s): 12.15. Ff, 14.60.Pq, 96.60.Jw The raison d'être for the existence of three well seperated families of charged fermions remains ununderstood in the context of present day high energy physics. The mystery regarding the fermion masses has further deepened with the observation of "neutrino oscillations" by the Superkamiokande Collaboration [1] implying nonzero masses for the neutrinos and thus, giving for the first time a strong signal for the physics beyond the standard model. In the absence of any deeper understanding of fermion masses, attempts have been made on the one hand to understand arbitrary standard model Yukawa couplings of the fermions from more fundamental theories such as GUTs [2] composite models [3], left right symmetric models [4], etc.. On the other hand, attempts have been made to discover phenomenological quark mass matrices, which are in tune with the low energy data(LED). In this regard, specific ansatz for the quark mass matrices have been tried with a fair degree of success [5] - [13] to explain quark mixing matrix. Similarly phenomenological neutrino mass matrices have been considered [13,14] which attempt to accomodate simultaneously the Solar Neutrino Problem (SNP), Atmospheric Neutrino Problem (ANP) and Neutrino Oscillations observed by LSND.

Texture zeros and weak basis transformations in the quark sector of the standard model

“…IVA 2, is especially interesting because the latest low-energy data shows that it is a viable model, something not considered or ruled out in Refs. [5,8,21]. Therefore, let us assume the following five-texture zeros model…”

Texture zeros and weak basis transformations

“…s 12 c 13 s 13 e −iδ 13 −s 12 c 23 − c 12 s 23 s 13 e iδ 13 c 12 c 23 − s 12 s 23 s 13 e iδ 13 s 23 c 13 s 12 s 23 − c 12 c 23 s 13 e iδ 13 −c 12 s 23 − s 12 c 23 s 13 e iδ 13 c 23 c 13…”

Phenomenological Implications of a Class of Lepton Mass Matrices

“…In particular, the latest low energy data disfavor [12] all quark mass matrices with five or more texture zeros. Four texture zero Ansätze is specially important since it can successfully describe not only the quark but also the lepton sector including the charged lepton and neutrino masses.…”