Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe Flavor-locked Flavorful Two Higgs Doublet Model
304
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We propose a new framework to generate the Standard Model (SM) quark flavor hierarchies in the context of two Higgs doublet models (2HDM). The `flavorful 2HDM couples the SM-like Higgs doublet exclusively to the third quark generation, while the first two generations couple exclusively to an additional source of electroweak symmetry breaking, potentially generating striking collider signatures. We synthesize the flavorful 2HDM with the `flavor-locking mechanism, that dynamically generates large quark mass hierarchies through a flavor-blind portal to distinct flavon and hierarchon sectors: Dynamical alignment of the flavons allows a unique hierarchon to control the respective quark masses. We further develop the theoretical construction of this mechanism, and show that in the context of a flavorful 2HDM-type setup, it can automatically achieve realistic flavor structures: The CKM matrix is automatically hierarchical with $|V_{cb}|$ and $|V_{ub}|$ generically of the observed size. Exotic contributions to meson oscillation observables may also be generated, that may accommodate current data mildly better than the SM itself.
rate research
Read More
The new round of experiments, MEG II, COMET/Mu2e, and Mu3e, would soon start to push the $mu to egamma$, $mu N to eN$ conversion, and $mu to 3e$ frontier, while Belle II would probe $tau to mugamma$ and $tau to 3mu$. In the general two Higgs doublet model with extra Yukawa couplings, we show that all these processes probe the lepton flavor violating (LFV) dipole transition that arises from the two loop mechanism, with scalar-induced contact terms subdominant. This is because existing data suggest the extra Yukawa couplings $rho_{mu e},, rho_{ee} lesssim lambda_e$, while $rho_{taumu},, rho_{tautau} lesssim lambda_tau$ and $rho_{tt} lesssim lambda_t$, with $lambda_i$ the usual Yukawa coupling of the Standard Model (SM), where $rho_{mu e}rho_{tt}$ and $rho_{taumu}rho_{tt}$ enter the $mu egamma$ and $taumugamma$ two loop amplitudes, respectively. With the $B_s to mumu$ decay rate basically consistent with SM expectation, together with the $B_s$ mixing constraint, we show that $B_s to tautau$ would also be consistent with SM, while $B_s to taumu$ and $B to Ktaumu$ decays would be out of reach of projected sensitivities, in strong contrast with some models motivated by the B anomalies.
A novel model embedding the two Higgs doublets in the popular two Higgs doublet models into a doublet of a non-abelian gauge group $SU(2)_H$ is presented. The Standard Model $SU(2)_L$ right-handed fermion singlets are paired up with new heavy fermions to form $SU(2)_H$ doublets, while $SU(2)_L$ left-handed fermion doublets are singlets under $SU(2)_H$. Distinctive features of this anomaly-free model are: (1) Electroweak symmetry breaking is induced from spontaneous symmetry breaking of $SU(2)_H$ via its triplet vacuum expectation value; (2) One of the Higgs doublet can be inert, with its neutral component being a dark matter candidate as protected by the $SU(2)_H$ gauge symmetry instead of a discrete $Z_2$ symmetry in the usual case; (3) Unlike Left-Right Symmetric Models, the complex gauge fields $(W_1^{prime}mp i W_2^{prime})$ (along with other complex scalar fields) associated with the $SU(2)_H$ do {it not} carry electric charges, while the third component $W^{prime}_3$ can mix with the hypercharge $U(1)_Y$ gauge field and the third component of $SU(2)_L$; (4) Absence of tree level flavour changing neutral current is guaranteed by gauge symmetry; and {it etc}. In this work, we concentrate on the mass spectra of scalar and gauge bosons in the model. Constraints from previous $Z^prime$ data at LEP and the Large Hadron Collider measurements of the Standard Model Higgs mass, its partial widths of $gammagamma$ and $Zgamma$ modes are discussed.
In the left-right symmetric model based on $SU(2)_Ltimes SU(2)_Rtimes U(1)_{B-L}$ gauge symmetry, there appear heavy neutral scalar particles mediating quark flavor changing neutral currents (FCNCs) at tree level. We consider a situation where such FCNCs give the only sign of the left-right model while $W_R$ gauge boson is decoupled, and name it semi-aligned two Higgs doublet model because the model resembles a two Higgs doublet model with mildly-aligned Yukawa couplings to quarks. We predict a correlation among processes induced by quark FCNCs in the model, and argue that future precise calculation of meson-antimeson mixings and CP violation therein may hint at the semi-aligned two Higgs doublet model and the left-right model behind it.
We calculate lepton flavor violating Z -> l^+ l^- decay in the framework of the general two Higgs Doublet model. In our calculations we used the constraints for the Yukawa couplings bar{xi}^{D}_{N,tau e} and bar{xi}^{D}_{N,taumu} coming from the experimental result of muon electric dipole moment and upper limit of the BR(mu -> egamma). We observe that it is possible to reach the present experimental upper limits for the branching ratios of such Z decays in the model III.
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.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
