Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTwo Higgs Doublet Type III Seesaw with mu-tau symmetry at LHC
113
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We propose a two Higgs doublet Type III seesaw model with $mu$-$tau$ flavor symmetry. We add an additional SU(2) Higgs doublet and three SU(2) fermion triplets in our model. The presence of two Higgs doublets allows for natural explanation of small neutrino masses with triplet fermions in the 100 GeV mass range, without fine tuning of the Yukawa couplings to extremely small values. The triplet fermions couple to the gauge bosons and can be thus produced at the LHC. We study in detail the effective cross-sections for the production and subsequent decays of these heavy exotic fermions. We show for the first time that the $mu$-$tau$ flavor symmetry in the low energy neutrino mass matrix results in mixing matrices for the neutral and charged heavy fermions that are not unity and which carry the flavor symmetry pattern. This flavor structure can be observed in the decays of the heavy fermions at LHC. The large Yukawa couplings in our model result in the decay of the heavy fermions into lighter leptons and Higgs with a decay rate which is about $10^{11}$ times larger than what is expected for the one Higgs Type III seesaw model with 100 GeV triplet fermions. The smallness of neutrino masses constrains the neutral Higgs mixing angle $sinalpha$ in our model in such a way that the heavy fermions decay into the lighter neutral CP even Higgs $h^0$, CP odd Higgs $A^0$ and the charged Higgs $H^pm$, but almost never to the heavier neutral CP even Higgs $H^0$. The small value for $sinalpha$ also results in a very long lifetime for $h^0$. This displaced decay vertex should be visible at LHC. We provide an exhaustive list of collider signature channels for our model and identify those that have very large effective cross-sections at LHC and almost no standard model background.
rate research
Read More
We study Two-Higgs-Doublet Models (2HDM) where Abelian symmetries have been introduced, leading to a drastic reduction in the number of free parameters in the 2HDM. Our analysis is inspired in BGL models, where, as the result of a symmetry of the Lagrangian, there are tree-level scalar mediated Flavour-Changing-Neutral-Currents, with the flavour structure depending only on the CKM matrix. A systematic analysis is done on the various possible schemes, which are classified in different classes, depending on the way the extra symmetries constrain the matrices of couplings defining the flavour structure of the scalar mediated neutral currents. All the resulting flavour textures of the Yukawa couplings are stable under renormalisation since they result from symmetries imposed at the Lagrangian level. We also present a brief phenomenological analysis of the most salient features of each class of symmetry constrained 2HDM.
We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ $chi$-square fitting approach by including theoretical and experimental constraints, such as S, T, and U oblique parameters, the production of standard model Higgs and its decay to $gammagamma$, $WW^*/ZZ^*$, $tau^+tau^-$, etc. The errors of analysis are taken at $68%$, $95.5%$, and $99.7%$ confidence levels. Due to the new Yukawa couplings being associated with $cos(beta-alpha)$ and $sin(beta -alpha)$, we find that the allowed regions for $sinalpha$ and $tanbeta$ in the type-III model can be broader when the dictated parameter $chi_F$ is positive; however, for negative $chi_F$, the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in the $hto Zgamma$ can be of ${cal O}(10%)$. Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get $Br(tto c(h, H) )< 10^{-3}$ for $m_h=125.36$ and $m_H=150$ GeV and $Br(tto cA)$ slightly exceeds $10^{-3}$ for $m_A =130$ GeV.
In this paper, the lepton flavor violating $tau^- to mu^-PP (PP=K^+K^-,K^0bar{K}^0,pi^+pi^-,pi^0pi^0)$ decays are studied in the framework of the two Higgs doublet model(2HDM) III. We calculate these decays branching ratios and get the bounds of model parameter $|lambda_{taumu}|$ from the experimental upper limits. Our results show that, the neutral Higgs bosons have tree-level contributions to these decays. Among these decays, the $tau^- to mu^- K^+K^-$ decay is most sensitive to $|lambda_{taumu}|$. In the existing parameters space, these decays could reach the measure capability of B factory. These processes can provide some valuable information to future research and furthermore present the reliable evidence to test the 2HDM III model.
In this paper, the lepton flavor violating $tau^- to mu^- V^0(V^0=rho^0,phi,omega)$ decays are studied in the framework of the two Higgs doublet model(2HDM) III. We present a computation of the the $gamma-$, $Z$ penguin and box diagrams contributions, and make an analysis of their impacts. Our results show that, among the $gamma-$ penguins, the penguins with neutral Higgs in the loop are very larger than those with charged Higgs in the loop. We find that the model parameter $lambda_{taumu}$ is tightly constrained at the order of $O(10^{-3})$ and the branching ratios of these decays are available at the experiment measure. With the high luminosity, the B factories have considerable capability to find these LFV processes. On the other hand, these processes can also provide some valuable information to future research and furthermore present the reliable evidence to test the 2HDM III model.
A Monte Carlo event generator is constructed for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the $rho$, behaving similarly to the standard-model Higgs boson, two extra neutral bosons $h$ and $h$, and a charged pair $H^pm$. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons $h$, $h$ and $H^pm$ couple directly only to the second generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell-Yan-type production processes of $h$, $h$ and $H^pm$ in proton-proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the $mu^+ mu^-$, $mu^+ u_mu$ and $mu^- bar u_mu$ channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in $p p$ collisions at center-of-mass energies of 8 TeV and 14 TeV for significant observations of the Higgs bosons $h$, $h$ and $H^pm$ in these muonic channels.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
