Effects Of Neutral Higgs Bosons Research Articles

B→K0*(1430)l+l−decays in supersymmetric theories

The weak decays of $B \to K^{\ast}_0(1430) l^{+} l^{-}$ ($l=\mu, \tau$) are investigated in Minimal Supersymmetric Standard Model (MSSM) and also in Supersymmetric (SUSY) SO(10) Grand Unified Models. Neutral Higgs bosons are the point of main focus in MSSM because they make quite a large contribution in exclusive $B \to X_{s} l^{+} l^{-}$ decays at large $\tan{\beta}$ regions of parameter space of SUSY models, as part of SUSY contributions is proportional to $\tan^{3}{\beta}$. The analysis of decay rate, forward-backward asymmetries and lepton polarization asymmetries in $B \to K^{\ast}_0(1430) l^{+} l^{-}$ show that the values of these physical observables are greatly modified by the effects of neutral Higgs bosons. In SUSY SO(10) GUT model, the new physics contribution comes from the operators which are induced by the neutral Higgs boson penguins and also from the operators with chirality opposite to that of the corresponding Standard Model (SM) operators. SUSY SO(10) effects show up only in the decay $B \to K^{\ast}_0 \mu^{+} \mu^{-}$ where the transverse lepton polarization asymmetries deviate significantly from the SM value while the effects in the decay rate, forward-backward asymmetries, the longitudinal and normal lepton polarization asymmetries are very mild. The transverse lepton polarization asymmetry is almost zero in SM and in MSSM model, whereas it can reach to -0.3 in SUSY SO(10) GUT model which could be seen at the future colliders; hence this asymmetry observable can be used to discriminate between different SUSY models.

Exclusive semileptonic decays ofΛb→Λl+l−in supersymmetric theories

The weak decays of ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}{l}^{+}{l}^{\ensuremath{-}}$ ($l=e$, $\ensuremath{\mu}$) are investigated in the minimal supersymmetric standard model (MSSM) and also in supersymmetric (SUSY) SO(10) grand unified models. In the MSSM special attention is paid to the neutral Higgs bosons (NHBs) as they make quite a large contribution in exclusive $B\ensuremath{\rightarrow}{X}_{s}{l}^{+}{l}^{\ensuremath{-}}$ decays at large $\mathrm{tan}\ensuremath{\beta}$ regions of parameter space of SUSY models, since part of SUSY contributions is proportional to ${tan}^{3}\ensuremath{\beta}$. The analysis of decay rate, forward-backward asymmetries, lepton polarization asymmetries, and the polarization asymmetries of the $\ensuremath{\Lambda}$ baryon in ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}{l}^{+}{l}^{\ensuremath{-}}$ show that the values of these physical observables are greatly modified by the effects of NHBs. In the SUSY SO(10) grand unified theory model, the new physics contribution comes from the operators which are induced by the NHBs' penguins and also from the operators having chirality opposite to that of the corresponding standard model (SM) operators. SUSY SO(10) effects show up only in the decay ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}+{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ where the longitudinal and transverse lepton polarization asymmetries deviate significantly from the SM value while the effects in the decay rate, forward-backward asymmetries, and polarization asymmetries of final state $\ensuremath{\Lambda}$ baryon are very mild. The transverse lepton polarization asymmetry in ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}+{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ is almost zero in the SM and in the MSSM model. However, it can reach to $\ensuremath{-}0.1$ in the SUSY SO(10) grand unified theory model and could be seen at the future colliders; hence this asymmetry observable will provide us useful information to probe new physics and discriminate between different models.

B → Kτ+τ− decay in the general two Higgs doublet model

We study the branching ratio, CP-violating asymmetry, forward-backward asymmetry and the CP-violating asymmetry in the forward-backward asymmetry for the exclusive decay B → Kτ+τ− in the two Higgs doublet model with tree level flavor changing neutral currents (model III). We analyse the dependencies of these quantities on the neutral Higgs boson contributions and the CP parameter sinθ in the model III. We observe that to determine the neutral Higgs boson effects, the measurements of the forward-backward asymmetry and the CP-violating asymmetry in the forward-backward asymmetry for the decay B → Kτ+τ− are promising.

The exclusive [formula omitted] decays in a CP softly broken two Higgs doublet model

We study the differential branching ratio, forward-backward asymmetry, CP-violating asymmetry, CP-violating asymmetry in the forward-backward asymmetry and polarization asymmetries in the B→ Kℓ +ℓ − and B→K ∗ℓ +ℓ − decays in the context of a CP softly broken two Higgs doublet model. We analyze the dependencies of these observables on the model parameters by paying a special attention to the effects of neutral Higgs boson (NHB) exchanges and possible CP-violating effects. We find that NHB effects are quite significant for both decays. A combined analysis of above-mentioned observables seems to be very promising as a testing ground for new physics beyond the SM, especially for the existence of the CP-violating phase in the theory.

Bs→τ+τ−γdecay in the general two Higgs doublet model including the neutral Higgs boson effects

We investigate the differential branching ratio, branching ratio, differential forward-backward asymmetry, the forward-backward asymmetry of the lepton pair and the lepton polarization asymmetry of the exclusive $B\to \tau^+ \tau^- \gamma$ decay in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependencies of these quantities on the model parameters and also on the neutral Higgs boson effects. We found that they get considerable enhancement from the two Higgs doublet model compared to the standard model and neutral Higgs boson effects are quite sizable.

Rare decay $B\rightarrow X_sl^+l^-$ in a CP spontaneously broken two-Higgs doublet model

The Higgs boson mass spectrum and couplings of neutral Higgs bosons to fermions are worked out i n a CP spontaneously broken two Higgs doublet model in the large tan$\beta$ case. The differential branching ratio, forward-backward asymmetry, CP asymmetry and lepton polarization for $B\to X_s l^+ l^-$ are computed. It is shown that effects of neutral Higgs bosons are quite significant when $\tan\beta$ is large. Especially, the CP violating normal polarization $P_N$ can be as large as several percents.

The exclusiveB→πell+ell−andB→ρell+ell−decays in the general two Higgs doublet model

We study the differential branching ratio, branching ratio and the forward-backward asymmetry for the exclusive $B \to \pi \ell^+ \ell^-$ and $B \to \rho \ell^+ \ell^-$ decays in the general two Higgs doublet model including the neutral Higgs boson effects. We analyze the dependencies of these quantities on the neutral Higgs boson contributions and the other model parameters. We observe that two Higgs doublet model with the neutral Higgs boson exchanges gives quite sizable contributions to these observables for both channels we consider. Since the neutral Higgs boson exchanges are the only source of the forward-backward asymmetry for $B \to \pi \tau^+ \tau^-$ decay, which is at the order of magnitude $1-10%$, measurement of this observable is promising to determine the neutral Higgs boson effects.

B → K *τ+τ− decay in the general two Higgs doublet model including the neutral Higgs boson effects

We study the CP violating asymmetry, the forward–backward asymmetry of the lepton pair and the CP asymmetry in the forward–backward asymmetry for the exclusive decay B → K*τ+τ− in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependences of these quantities on the model III parameters. We found that the physical parameters studied above are of the order of 1%, and neutral Higgs boson effects are detectable for large values of the coupling ξ̄N,ττD.

Exclusive semileptonic rare decaysB→(K,K*)l+l−in supersymmetric theories

The invariant mass spectrum, forward-backward asymmetry, and lepton polarizations of the exclusive processes $B\to K(K^*)\ell^+ \ell^-, \ell=\mu, \tau$ are analyzed under supersymmetric context. Special attention is paid to the effects of neutral Higgs bosons (NHBs). Our analysis shows that the branching ratio of the process $\bkm$ can be quite largely modified by the effects of neutral Higgs bosons and the forward-backward asymmetry would not vanish. For the process $\bksm$, the lepton transverse polarization is quite sensitive to the effects of NHBs, while the invariant mass spectrum, forward-backward asymmetry, and lepton longitudinal polarization are not. For both $\bkt$ and $\bkst$, the effects of NHBs are quite significant. The partial decay widths of these processes are also analyzed, and our analysis manifest that even taking into account the theoretical uncertainties in calculating weak form factors, the effects of NHBs could make SUSY shown up.

Signatures of Higgs sector CP violation in top quark pair production at proton-proton supercolliders

In the context of two-Higgs doublet extensions of the standard electroweak theory we investigate CP-violating effects of neutral Higgs bosons ϕ in pp→t tX at LHC and SSC energies. We identify the resulting t t spin-momentum correlations in the partonic production processes gg, q q→t t . An interesting possibility is resonant ϕ production in gluon-gluon fusion and its subsequent decay ϕ→t t which leads to a sizeable spin-spin correlation at the parton level. We propose and compute two triple product correlations with which these spin-spin correlations can be traced in the t t decay products.