b→sγin the littlest Higgs model

Abstract

The inclusive process b→s␥ is studied in the littlest Higgs model. The contributions arising from new particles are normally suppressed by a factor of O(v 2 / f 2 ). Because of the large uncertainties of experimental measurements and theoretical predictions, the model parameters can escape from the constraints of present experiments provided f у1 TeV.

Particle-antiparticle mixing,εK, ΔΓq, ASLq, ACP(Bd→ψKS), ACP(Bs→ψphi) and B→Xs,dγ in the Littlest Higgs model with T-parity

“…The first calculation of the B → X s γ decay within the LH model has been done within the Littlest Higgs model without T-parity in [22]. We have confirmed this result.…”

“…As a consequence the contributions of the new particles to FCNC processes turn out to be at most 10 − 20% [19]- [22], which will not be easy to distinguish from the SM in view of experimental and theoretical uncertainties.…”

B, D and K decays

“…The contribution tō B → X s γ from these new particles has been studied in Refs. [142,146] for the original Littlest Higgs model and in Ref. [159] for the model in which an additional Tparity and additional particles are introduced to preserve the SU(2) custodial symmetry.…”

“…Consequently, EW precision tests are satisfied only for quite large values of the NP scale f ≥ (2-3) TeV [138,139] that are unable to solve the little hierarchy problem. Since the LH model belongs to the class of models with Constrained Minimal Flavor Violation (CMFV) [12], the contributions of the new particles to FCNC processes turn out to be at most (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)% [140][141][142][143][144][145][146].…”

Top Partner Production at e+e- Collider in the Littlest Higgs Model with T-Parity

“…Besides, a search has been performed in pair-produced exotic top partners, each decay to an on-shell top (or antitop) quark and a longlived undetected neutral particle [11]. Apart from direct searches, the indirect searches for the top partners through their contributions to the electroweak precision observables (EWPOs) [12,13], -pole observables [14][15][16], and the flavor physics [17][18][19][20][21][22][23][24] have been extensively investigated. The null results of the top partners, in conjunction with the EWPOs and the recent Higgs data, have tightly constrained the parameter space of the LHT model [25][26][27][28][29][30].…”