Related papers: Flavor changing neutral currents in 331 models
We study the contribution to flavor changing neutral current processes from box diagrams with light higgsinos and squarks. Starting with just the Cabbibo Kobayashi Maskawa (CKM) phase, we find contributions to the $K^0$ and $B^0$ meson mass…
Assuming the existence of right-handed neutrinos, we consider an electroweak model based on the gauge symmetry $SU(4)_L\otimes U(1)_N$. We study the neutral currents coupled to all neutral vector bosons present in the theory. There are no…
We give an overview of recent progress in the study of fermion mass and flavor mixing phenomena. The hints exhibited by the quark and lepton mass spectra towards possible underlying flavor symmetries, from which realistic models of mass…
We discuss $Z$ mediated flavour changing neutral currents within a model where the hierarchical quark and lepton masses are explained via a fourth vector-like family, together with a scalar sector consisting of two Higgs doublets augmented…
Phase diagram of a chiral random matrix model with the degenerate ud quarks and the s quark at finite temperature and density is presented. The model exhibits a first-order transition at finite temperature for three massless flavors, owing…
Flavor changing neutral current processes are studied in the littlest Higgs model with T-parity. It is found that the logarithmic divergence reported earlier in Z boson flavor changing processes is exactly canceled by contributions from…
We analyse scalar flavour-changing neutral currents of down-type quarks in models with two Higgs doublets, coupled separately to up- and down-type quarks, in the limit where the ratio of the two expectation values ($\tan \beta = v_u/v_d$)…
We address the question, how general is the gauge sector in extra-dimensional models which explain hierarchies of masses and mixings of quarks, charged leptons and neutrinos in terms of a single family of multidimensional fermions. We give…
We propose a novel method to study flavor-changing neutral currents in the $e^+e^-\to D^{*0}$ and $e^+e^-\to B_{s}^* $ transitions, tuning the energy of $e^+e^-$- collisions to the mass of the narrow vector resonance $D^{*0}$ or $ B_{s}^*$.…
The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…
The proper inclusion of flavor in the Dijkgraaf-Vafa proposal for the solution of N=1 gauge theories through matrix models has been subject of debate in the recent literature. We here reexamine this issue by geometrically engineering…
We analyze the effects of a tree level flavor changing $tcZ$ vertex induced by a mixing with new isosinglet $Q=2/3$ quarks, on the effective $bsZ$ vertex. We compute the contributions arising from the new electroweak penguin diagrams…
Quark and lepton flavor physics presents us with a basic question: Can we understand the pattern of masses and mixings of the known quarks and leptons, and how do present and proposed measurements help to advance that goal? Topics discussed…
We compute the flavor changing neutral current process $B \to X_s \mu^+ \mu^-$ in technicolor models with scalars. We find that the branching ratio can be enhanced relative to that of the Standard Model by as much as 60%. The full parameter…
We review the very stringent lower bounds on the string scale that arise from flavor considerations in models with intersecting branes. Despite the absence of a realistic flavor structure at tree level, flavor changing interactions induce a…
A new suggestion for organizing the charged pseudo scalar mesons is presented. The simple Non-relativistic (NR) potential model employs a single value of the light quark mass and determines the potential coupling constant directly from the…
In supersymmetric grand-unified models, the lepton mixing matrix can possibly affect flavor-changing transitions in the quark sector. We present a detailed analysis of a model proposed by Chang, Masiero and Murayama, in which the…
We examine flavour-changing neutral-current decays of the top quark, $t\to q \gamma$, $t \to qZ$, $t \to q H$, and $ t\to q g$ (with $q=u, c$), in the Alternative Left-Right Model, a left right-symmetric model featuring exotic quarks and…
We study the implications of a large nu_mu - nu_tau mixing angle on flavour changing transitions of quarks and leptons in supersymmetric extensions of the standard model. Two patterns of supersymmetry breaking are considered, models with…
The charged fermion mass matrices are always invariant under $U(1)^3$ symmetry linked to the fermion number transformation. A class of two Higgs doublet models (2HDM) can be identified by requiring that the definition of this symmetry in an…