Related papers: Precise predictions for mt, Vcb and tan
We determine the top quark mass m_t using t-tbar pairs produced in the D0 detector by \sqrt{s} = 1.8 TeV p-pbar collisions in a 125 pb^-1 exposure at the Fermilab Tevatron. We make a two constraint fit to m_t in t-tbar -> b W^+bbar W^-…
In simple SO(10) SUSY GUTs the top, bottom and tau Yukawa couplings unify at the GUT scale. A naive renormalization group analysis, neglecting weak scale threshold corrections, leads to moderate agreement with the low energy data. However…
I present a new model for the quark mass matrices, which uses four scalar doublets together with a horizontal symmetry S3 x Z3. The model is inspired on a suggestion made a few years ago by Ma, but it is different. The predictions |Vts|…
Grand unified theories with fermions transforming as irreducible representations of a discrete nonabelian flavor symmetry can lead to realistic fermion masses, without requiring very small fundamental parameters. We construct a specific…
A fermion mass matrix ansatz is proposed in the context of Grand Unified Supersymmetric Theories (GUTs). The fermion mass matrices are evolved down to the electroweak scale by solving the renormalization group equations for the gauge and…
The determination of the Yukawa coupling of the top quark to the Higgs boson is one of the most important measurements that a future e^+e^- linear collider could provide. For a Higgs boson of mass greater than 350 GeV, this coupling can be…
We present an ansatz for the quark and lepton mass matrices, derivable from SO(10) type GUTs, which accommodates a heavy $(> 92 GeV)$ top quark and permits large mixings in the $\nu_\mu \leftrightarrow \nu_\tau$ sector (as suggested by the…
A novel relation is found which gives the 2-3 lepton mixing angle in terms of quark masses and CKM mixing: \tan\theta_{\mu\tau}=(m_b/m_s)V_{cb}. This relation, which is remarkably in good agreement with the quark data and the large lepton…
We analyse the structure of Yukawa couplings in local SU(5) F-theory models with $E_8$ enhancement. In this setting the $E_8$ symmetry is broken down to SU(5) by a 7-brane configuration described by T-branes, all the Yukawa couplings are…
We discuss aspects of the low energy phenomenology of the MSSM, in the large $\tan {\beta} $ regime. We explore the regions of the parameter space where the $h_t$ and $h_b$ Yukawa couplings exhibit a fixed point structure, using previous…
We explore the implications of t-b-tau (and b-tau) Yukawa coupling unification condition on the fundamental parameter space and sparticle spectroscopy in the minimal gauge mediated supersymmetry breaking (mGMSB) model. We find that this…
We analyze the stability of the electroweak vacuum in neutrino mass models containing right handed neutrinos or fermionic isotriplets. In addition to considering absolute stability, we place limits on the Yukawa couplings of new fermions…
We calculate the values and 1 sigma ranges of the running quark and lepton Yukawa couplings as well as of the quark mixing parameters at various energy scales, i.e. at M_Z, 1 TeV, 3 TeV, 10 TeV and at the GUT scale, to provide useful input…
We discuss conditions under which bi-large mixing in the lepton sector is achieved assuming that all Yukawa matrices and the right-handed neutrino mass matrix have the same singular form in the leading order. Due to obvious quark lepton…
If the parameter $tan \beta$ of the minimal supersymmetric model is large, then $b$ and $\tau$ Yukawa interactions are important. These can significantly modify the masses and decays of sparticles. We describe new calculations which allow a…
We propose a model of fermion masses and mixings based on $SU(5)$ grand unified theory (GUT) and a $D_{4}$ flavor symmetry. This is a highly predictive 4D $SU(5)$ GUT with a flavor symmetry that does not contain a triplet irreducible…
Study of the MSSM in large tan$\beta$ regime has to include correlations between the constraints presented by the low energy values of the b quark mass and BR($b \to s\gamma$). Both quantities receive SUSY contributions enhanced by…
Pursuing a bottom-up approach to explore which flavor symmetry could serve as an explanation of the observed fermion masses and mixings, we discuss an extension of the standard model (SM) where the flavor structure for both quarks and…
We evaluate the finite 1-loop threshold corrections, proportional to $tan\beta$, to the down quark mass matrix. These result in corrections to down quark masses and to Cabibbo-Kobayashi-Maskawa [CKM] matrix elements. The corrections to CKM…
We find that the one-loop correction to the ratio of Yukawa coupling and gauge coupling in the gauge-Higgs unification, "gauge-Yukawa universality violation", is finite and calculable in any space-time dimension. Applying this result to the…