相关论文: Explaining Why the u and d Quark Masses are Simila…
Current experimental data suggest some relations between the Kobayashi-Maskawa Matrix and the quark mass ratios, namely $|V_{us}| \sim \sqrt{m_d / m_s}$, $|V_{ub} / V_{cb}| \sim \sqrt{m_u / m_c}$ and $|V_{cb}| \sim m_s / m_b$. We consider…
A class of models is considered in which the masses only of the third generation of quarks and leptons arise in the tree approximation, while masses for the second and first generations are produced respectively by one-loop and two-loop…
A scenario combining a model of early (TeV) unification of quarks and leptons with the physics of large extra dimensions provides a natural mechanism linking quark and lepton masses at TeV scale. This has been dubbed as early quark-lepton…
It is shown that if, from the starting point of a universal rank-one mass matrix long favoured by phenomenologists, one adds the assumption that it rotates (changes its orientation in generation space) with changing scale, one can…
I explore the rich phase diagram of two-flavor QCD as a function of the quark masses. The theory involves three parameters, including one that is CP violating. As the masses vary, regions of both first and second order transitions are…
Recently, we have proposed a quark mass matrix model based on U(3)$\times$U(3)$'$ family symmetry, in which up- and down-quark mass matrices $M_u$ and $M_d$ are described only by complex parameters $a_u $ and $a_d $, respectively. When we…
Under the assumptions that 1) the quark/lepton mass matrices take Froggatt-Nielsen's factorized power form \lambda^{\psi_i+\psi_j} with anomalous U(1) charges \psi_i, and 2) the U(1) charges \psi_i respect the SU(5) GUT structure, we show…
We show that the observed structure of quark and lepton masses and mixing angles can arise entirely geometrically from superstring constructions, at the renormalizable level. The model we consider is a $Z_3$ orbifold compactification of…
The comparison of the CKM mixing angles with the leptonic mixings implied by the recent atmospheric and solar neutrino data exhibits an interesting complementarity. This pattern can be understood in the context of the SU(5) grand…
We describe a solution to a long standing puzzle about the difference in textures of quark CKM and lepton PMNS mixing matrices by deriving their common representation. We show how the difference in texture of the two matrices arises from…
Recent developments on approaches to the quark lepton mass problem are reviewed. In particular we discuss dynamical calculations of the top quark mass at (a) the infrared quasifixed point of the Minimal Supersymmetric Standard Model…
It is known that the charged lepton masses obey to high precision an interesting empirical relation (Koide relation). In turn, the light neutrino masses cannot obey such a relation. We note that if neutrinos acquire their mass via the…
A model of quark mass matrices from six dimensions, which is nearly democatic in nature and which is previously constructed by two of us (PQH and MS), is studied in detail in this manuscript. We found that not only it fits all the six quark…
Within the broad context of quark-lepton unification, we investigate the implications of broken continuous family symmetries which result from requiring that in the limit of exact symmetry, the Dirac mass matrices yield hierarchical masses…
In recent years a new potential symmetry of fundamental particle physics has been investigated --- discrete quark-lepton symmetry. When this symmetry is implemented, however, it often leads to either of the unrealistic predictions…
It is proposed that all flavor mixing is caused by the mixing of the three quark and lepton families with vectorlike fermions in 5 + 5-bar multiplets of SU(5). This simple assumption implies that both V_{CKM} and U_{MNS} are generated by a…
Quark-lepton symmetric models are a class of gauge theories motivated by the similarities between the quarks and leptons. In these models the gauge group of the standard model is extended to include a ``color'' group for the leptons.…
Peccei-Quinn (PQ) mechanism based on a chiral global U(1) symmetry is considered to be a simple and elegant solution for strong CP problem. Fact that the mechanism could be experimentally examined through the axion search makes it much more…
Under the assumptions that 1) the quark/lepton mass matrices take Froggatt-Nielsen's factorized power form \lambda^{\psi_i+\psi_j} with anomalous U(1) charges \psi_i, and 2) the U(1) charges \psi_i respect the SU(5) GUT structure, we show…
To explain quark and lepton masses and mixing angles, one has to extend the standard model, and the usual practice is to put the quarks and leptons into irreducible representations of discrete groups. We argue that discrete flavor…