We analyze the quasi-two-body decays $B^+\toπ^+ρ(770,1450)^0 \toπ^+ K^+K^-$ in the perturbative QCD approach. The results in this work do not support that large branching fractions contributed by the resonances $ρ(770,1450)^0$ in the $B^\pm \to π^\pm K^+K^-$ decays. The virtual contribution for $K^+K^-$ from the tail of the resonance $ρ(770)^0$ which has been ignored in the experimental studies is about $1.5$ times of the $ρ(1450)^0 \to K^+K^-$ contribution, with the predicted branching fractions ${\mathcal B}_v=(1.31\pm0.27)\times10^{-7}$ and ${\mathcal B}=(8.96\pm2.61)\times10^{-8}$, respectively, for these two subprocesses in the $B^\pm \to π^\pm K^+K^-$ decays. The absence of $ρ(770)^0\to K^+K^-$ for the decay amplitude of a three-body hadronic $B$ decay involving charged kaon pair could probably result in a larger proportion for the contribution from the resonance $ρ(1450)^0$ in the experimental analysis.
We construct the theoretical framework for quasi-two-body $D$ meson decays with the help of pion and kaon electromagnetic form factors, and with which we study the contributions of the subprocesses $ρ(770,1450)\to K\bar{K}$ for the three-body $D$ decays within the flavour $SU(3)$ symmetry. Because of the limitations imposed by phase space and strong coupling, the contributions for kaon pair from the virtual bound state $ρ(770)$ are channel-dependent and generally small for the concerned three-body $D$ decays. But some quasi-two-body processes could still be observed in the Dalitz plot analyses…
Contributions of the subprocesses $ρ(770,1450,1700)\to K \bar{K}$ and $ω(782,1420,1650)\to K \bar{K}$ for the three-body decays $B\to η^{(\prime)} K\bar{K}$
Shanxi University（山西大学）；Nanjing Institute of Technology（南京工程学院）
We study the contribution of gluon induced partonic subprocesses to Z gamma pair production at hadron colliders. These processes contribute only at next-to-next-to-leading order but are potentially enhanced by two factors of the gluon parton densities. However, we find that their contribution is modest and that next-to-leading order calculations give reliable predictions.
We study the contributions for the $K^+K^-$ and $K^0\bar K^0$ originated from the intermediate states $ϕ(1020)$ and $ϕ(1680)$ in the charmless three-body decays $B\to K\bar K h$, with $h=(π, K)$, in the perturbative QCD approach. The subprocesses $ϕ(1020,1680)\to K\bar K$ are introduced into the distribution amplitudes of $K\bar K$ system via the kaon electromagnetic form factors with the coefficients taken from the fitted results. The predictions of the branching fractions for the decays $B\toϕ(1680)h$ with the intermediate state $ϕ(1680)$ decays into $K^+K^-$ or $K^0\bar K^0$ are about $6\%$…
The contributions for the kaon pair from the intermediate states $ρ(1450)^+$ and $ρ(1700)^+$ in the decays $B^+ \to \bar{D}^0 K^+ \bar{K}^0$, $B^0 \to D^- K^+ \bar{K}^0$, and $B_s^0 \to D_s^-K^+ \bar{K}^0$ are analyzed within the perturbative QCD factorization approach. The decay amplitudes for all concerned decays in this work are dominated by the factorizable Feynman diagrams with the emission of the kaon pair, and the charged $ρ$ mesons should be of great importance in the $KK$ channel of the related three-body $B$ decays. Moreover, these quasi-two-body decays are CKM-favored, and the relev…
The most general model-independent analysis of the rare $B$ decay, $\Bsll$, is presented. There are ten independent local four-Fermi interactions which may contribute to this process. The branching ratio, the forward-backward asymmetry, and the double differential rate are written as functions of the Wilson coefficients of the ten operators. We also study the correlation between the branching ratio and the forward-backward asymmetry by changing each coefficient. This procedure tells us which types of operator contribute to the process, and it will be very useful to pin down new physics systema…
As we amass more LHC data, we continue to search for new and improved methods of visualizing search results, in ways that are as model-independent as possible. The simplified limits framework is an approach developed to recast limits on searches for narrow resonances in terms of products of branching ratios (BRs) corresponding to the resonance's production and decay modes. In this work, we extend the simplified limits framework to a multidimensional parameter space of BRs, which can be used to unfold an ambiguity in the simplified parameter $ζ$ introduced when more than one channel contributes…
We study the $τ^- \to ν_τ π^{-}π^{0}\ell^{+}\ell^{-}$ ($\ell=e,\,μ$) decays, which are $O(α^2)$-suppressed with respect to the dominant di-pion tau decay channel. Both the inner-bremsstrahlung and the structure- (and model-)dependent contributions are considered. In the $\ell=e$ case, structure-dependent effects are $\mathcal{O}(1\%)$ in the decay rate, yielding a clean prediction of its branching ratio, $2.3\times10^{-5}$, measurable with BaBar or Belle(-II) data. For $\ell=μ$, both contributions have similar magnitude and we get a branching fraction of $(1.6\pm0.3)\times10^{-7}$, reachable b…
In this paper, we calculate neutron and proton decay rates and branching ratios in a predictive SO(10) SUSY GUT which agrees well with low energy data. We show that the nucleon lifetimes are consistent with the experimental bounds. The nucleon decay rates are calculated using all one-loop chargino and gluino dressed diagrams regardless of their chiral structure. We show that the four-fermion operator $C_{jk} (u_R {d_j}_R)({d_k}_L {ν_τ}_L)$, commonly neglected in previous nucleon decay calculations, not only contributes significantly to nucleon decay, but, for many values of the initial GUT par…
We compute the branching ratios for the rare top quark decays t to c gamma and t to c Z mediated by effective flavor changing neutral couplings at the next-to-leading order in QCD including the effects due to operator mixing. After re-suming contributions of order [alpha_s log (Lambda / m_t)]^n, where Lambda is the scale at which the effective operators are generated, at leading log level using renormalization group methods, we compute finite matrix element corrections and study the effects of experimental kinematic cuts on the extracted branching ratios. We find that the t to c gamma decay ca…
In principle, this paper suggests powerful laser technology as a promising instrument that can be experimentally useful to control the lifetime and branching ratio for an unstable particle decay. In a recent paper [arXiv:2101.00224], we calculated theoretically the $W^{-}$-boson leptonic decay $(W^{-}\rightarrow \ell^{-} \barν_{\ell})$ in the presence of a circularly polarized laser and we showed that the laser significantly contributed to the diminution of the leptonic decay rate. In this paper, as a continuation of the previous one, we mainly deal with the theoretical calculation of the $W^{…
We identify two Cabibbo suppressed $D^+$ decay modes with anomalously high branching ratios which are not simply explained by any model. All standard model diagrams that can contribute to these decays are related by symmetries to diagrams for other decays that do not show any such enhancement. If these high branching ratios are confirmed by more precise experiments, they may require new physics to explain them. Anomalies in $D_s$ decays and tests for possible violation of G-parity are discussed.
Implications of TeV Flavor Physics for the ΔI =1/2 Rule and the B-meson Semileptonic Branching Ratio
弱相互作用现象学和标准模型之间的两个显著差异在于$K$衰变中$ΔI={1\over 2}$增强的大尺寸和$B$半轻子分支比的小值。我们认为，这些差异是自然解释的色磁偶极子运营商产生的新物理在TeV尺度。这些运营商是密切相关的图，有助于夸克质量矩阵，我们展示了如何适当的增强的强子衰变的$s$和$b$夸克可以链接到特定的Cabbibo-Kobayaski-Maskawa混合角或夸克质量的产生。我们确认我们的模型独立的分析，详细考虑超对称模型和工艺色模型与工艺。这幅图对$B$系统有额外的唯象预测：由于$b\to sg$的大速率，无粲非轻子$B$衰变的分支比应该是20%，而对$b\rightarrow s γ$没有危险的新贡献。对$b \to d γ$的可观贡献是包含该机制的模型的共同特征。在techniscalar模型中，$Z b \bar b$偶联增强，与对$b \to s μ^+ μ^-$的相当大的贡献相关。
We consider nonleptonic Cabibbo--allowed $Λ_b$ decays in the factorization approximation. We calculate nonleptonic decays of the type $ Λ_b \to Λ_c P $ and $ Λ_b \to Λ_c V $ relative to $\bar{B}_d \to D^+ P$ and $\bar{B}_d \to D^+ V$ where we include among the pseudoscalar states(P) and the vector states(V) the newly discovered $D_s$ resonances, $D_s(2317)$ and $D_s(2460)$. In the ratio of $Λ_b$ decays to $D_s(2317)$ and $D_s(2460)$ relative to the $\bar{B}_d$ decays to these states, the poorly known decay constants of $D_s(2317)$ and $D_s(2460)$ cancel leading to predictions that can shed lig…
The mixing between nonstrange and strange quark wavefunctions in the $ω$ and $ϕ$ mesons leads to a small predicted branching ratio $\b(D_s^+ \to ωe^+ ν_e) = {\cal O}(10^{-4})(δ/3.34^\circ)^2$, where $δ$ is the mixing angle. The value $δ= -3.34^\circ$ is obtained in a mass-independent analysis, while a mass-dependent analysis gives $δ= -0.45^\circ$ at $m(ω)$ and $-4.64^\circ$ at $m(ϕ)$. Measurement of this branching ratio thus can tell whether the decay is dominated by $ϕ$--$ω$ mixing, or additional nonperturbative processes commonly known as "weak annihilation" (WA) contribute. The role of WA …
The b to d d s bar transition gives extremely small branching ratios within the standard model, thus providing an appropriate ground for testing new physics. Using renormalization group technique we determine the Wilson coefficients and the mixing of the operators which contribute to the b to d d s bar transition. We consider contributions to this decay mode from the supersymmetric standard model with and without R-parity, as well as from a model with an additional neutral Z' gauge boson. Using Belle and BaBar upper bounds for the B^- to pi^- pi^- K^+ branching ratio we constrain contributions…
In this paper the next-to-leading order (NLO) corrections to $B_c$ meson exclusive decays to S-wave charmonia and light pseudoscalar or vector mesons, i.e. $π$, $K$, $ρ$, and $K^*$, are performed within non-relativistic (NR) QCD approach. The non-factorizable contribution is included, which is absent in traditional naive factorization (NF). And the theoretical uncertainties for their branching ratios are reduced compared with that of direct tree level calculation. Numerical results show that NLO QCD corrections markedly enhance the branching ratio with a K factor of 1.75 for $B_{c}^{\pm}\to η_…
Using a successful framework for describing S-wave hadronic decays of light hyperons induced by a subprocess $s \to u (\bar u d)$, we presented recently a model-independent calculation of the amplitude and branching ratio for $Ξ^-_b \to Λ_b π^-$ in agreement with a LHCb measurement. The same quark process contributes to $Ξ^0_c \to Λ_c π^-$, while a second term from the subprocess $cs \to cd$ has been related by Voloshin to differences among total decay rates of charmed baryons. We calculate this term and find it to have a magnitude approximately equal to the $s \to u (\bar u d)$ term. We argue…
We study the contributions to the branching ratios of $B_{s(d)}\to γγ$ decay in the sequential fourth generation model (SM4). We find that the theoretical values of the branching ratios, ${\rm BR}(B_{s(d)}\toγγ)$, including the contributions of $m_{t'}$ and the new $4 \times 4$ CKM (CKM4) matrix factors, $|V^{*}_{t's}V_{t'b}|$ and $|V^{*}_{t'd}V_{t'b}|$, are much different from the minimal standard model (SM) predictions. The new physics effects, especially contributed from the CKM4 matrix factors, can provide more than one order enhancement to the SM prediction. It is shown that the decay $B_…
We list all scalar and vector leptoquark states that contribute to the b -> s l+ l- effective Hamiltonian. There are altogether three scalar and four vector leptoquarks that are relevant. For contribution of each state we infer the correlations between effective operators and find that only two baryon number-violating vector leptoquarks give rise to scalar and pseudoscalar four-fermion operators, whereas the scalar states can contribute to those operators only when two states with same charge are present. We bound the resulting Wilson coefficients by imposing experimental constraints coming fr…
We perform a model independent analysis of new physics in $B^*_s \rightarrow μ^+ μ^-$ decay. We intend to identify new physics operator(s) which can provide large enhancement in the branching ratio of $B^*_s \rightarrow μ^+ μ^-$ above its standard model prediction. For this, we consider new physics in the form of vector, axial-vector, scalar and pseudoscalar operators. We find that scalar and pseudoscalar operators do not contribute to the branching ratio of $B^*_s \rightarrow μ^+ μ^-$. We perform a global fit to all relevant $b \to s μ^+ μ^-$ data for different new physics scenarios. For each…
The flavor-changing neutral current decay processes of the $B$ and $B_c$ mesons with the final states involving spin-$1/2$ particles are investigated. By considering the background of the Standard Model where $ν\barν$ contributes the missing energy and the experimental upper bounds for the branching fractions, we get the constraints of the coupling constants of the quark-antiquark and the assumed invisible particles $χ\barχ$. The constraints of the coupling constants are then used to study the similar processes of the $B_c$ meson. At some specific region of $m_χ$, the upper limit of BR($B_c\to…
We study the Higgs boson decays and production via gluon fusion at the LHC as a probe of two typical littlest Higgs models which introduce a top quark partner with different (even and odd) T-parity to cancel the Higgs mass quadratic divergence contributed by the top quark. For each model we consider two different choices for the down-type quark Yukawa couplings. We first examine the branching ratios of the Higgs boson decays and then study the production via gluon fusion followed by the decay into two photons or two weak gauge bosons. We find that the predictions can be quite different for dif…
The framework under which decays $Λ_{b}(\frac{1}{2}^{+})\rightarrow B(\frac{1}{2}^{+})+M$ are analyzed is not applicable for the decays $Λ_{b}(\frac{1}{2}^{+})\rightarrow B^{\ast}(\frac{3}{2} ^{+})+M$. These decays occur through a baryon pole $Σ^{0}_{c}$ which is generated by the W-exchange diagram in the process $b+u \xrightarrow {W} c+d$. The effective Hamiltonian which arises from the W-exchange diagram is expressed in the non relativistic limit. Since $% Σ^{0}_{c}$ belongs to representation $6$ of SU(3), it contributes to two sets of decays: $Λ_{b}\rightarrowΔ^{0}D^{0},Δ^{-}D^{+},% Σ^{*-}D…
Recent evidence from observation of the flavor-changing neutral current decay B_s to mu+ mu- by the LHCb collaboration B(B_s to mu^+ mu^-) = (3.2 * 10^{-9}), is consistent with the latest standard model prediction B(B_s to mu^+ mu^-) = (3.23 +- 0.27) * 10^{-9}. While New Physics can still affect this decay amplitude, its contribution is certainly not the dominant one. We analyze branching ratios of the decays B_s to mu+ mu- X, with X = a photon or neutrino anti-neutrino pair, which can mimic B_s to mu+ mu- on portions of the parameter space where X is soft. We perform a model-independent stand…
We compute branching ratios of $B\to Kπ$ decays in the framework of perturbative QCD factorization theorem. Decay amplitudes are classified into the topologies of tree, penguin and annihilation, all of which contain both factorizable and nonfactorizable contributions. These contributions are expressed as the convolutions of hard $b$ quark decay amplitudes with universal meson wave functions. It is shown that (1) matrix elements of penguin operators are dynamically enhanced compared to those employed in the factorization assumption; (2) annihilation diagrams are not negligible, contrary to comm…
The branching fraction measurement of the SM-like Higgs boson decay into two muons at 1.4 TeV CLIC will be described in this paper contributed to the LCWS13. The study is performed in the fully simulated ILD detector concept for CLIC, taking into consideration all the relevant physics and the beam-induced backgrounds, as well as the instrumentation of the very forward region to tag the high-energy electrons. Higgs couplings are known to be sensitive to BSM physics and we prove that BR times the Higgs production cross section can be measured with approximately 35.5% statistical accuracy in four…
The semileptonic decays and two-body nonleptonic decays of light baryon octet ($T_8$) and decuplet ($T_{10}$) consisting of light $u,d,s$ quarks are studied with the SU(3) flavor symmetry in this work. We obtain the amplitude relations between different decay modes by the SU(3) irreducible representation approach, and then predict relevant branching ratios by present experimental data within $1 σ$ error. We find that the predictions for all branching ratios except $\mathcal{B}(Ξ\rightarrow Λ^0π)$ and $\mathcal{B}(Ξ^*\rightarrow Ξπ)$ are in good agreement with present experimental data, that im…
We study Cabibbo-favored (CF) and singly Cabibbo-suppressed (SCS) two-body hadronic weak decays of the antitriplet charmed baryons $Λ_c^+$, $Ξ_c^0$ and $Ξ_c^+$ with more focus on the last two. Both factorizable and nonfactorizable contributions are considered in the topologic diagram approach. The estimation of nonfactorizable contributions from $W$-exchange and inner $W$-emission diagrams relies on the pole model and current algebra. The non-perturbative parameters in both factorizable and nonfactorizable parts are calculated in the MIT bag model. Branching fractions and up-down decay asymmet…
The factorization theorem in Decays of $B_{(s)}$ mesons to two charmed mesons (both pseudoscalar and vector) can still be proved in the leading order in $m_D/m_B$ and $Λ_{\rm{QCD}}/m_D$ expansion. Working in the perturbative QCD approach, we find that the factorizable emission diagrams are dominant. Most of branching ratios we compute agree with the experimental data well, which means that the factorization theorem seems to be reliable in predicting branching ratios for these decays. In the decays of a $B$ meson to two vector charmed mesons, the transverse polarization states contribute $40%-5…
We analyze the prospects of reconstructing the mass of a heavy charged Higgs boson %have been analyzed in the context of a Type X two-Higgs doublet model where a light pseudoscalar $A$ in the mass range $40-60$ GeV is phenomenologically allowed, and is in fact favoured if one wants to explain the muon anomalous magnetic moment. The associated production of charged Higgs with the pseudoscalar $A$ and subsequent decay of the charged Higgs into a $W$ and $A$, is found to be our relevant channel. The branching ratio for $H^+ \to W^+ A$ with $M_{H^+} \sim 200$ GeV, is close to 50\%. The hadronic de…
In the quark-diagram scheme, we study the charmed baryon decays of ${\bf B}_c\to {\bf B}^* M$, where ${\bf B}_c$ is $Λ_c^+$ or $Ξ_c^{+(0)}$, together with ${\bf B}^*$ ($M$) the decuplet baryon (pseudoscalar meson). It is found that only two $W$-exchange processes are allowed to contribute to ${\bf B}_c\to {\bf B}^* M$. Particularly, we predict ${\cal B}(Λ_c^+ \to Σ^{*0(+)} π^{+(0)})=(2.8\pm 0.4)\times 10^{-3}$, which respects the isospin symmetry. Besides, we take into account the $SU(3)$ flavor symmetry breaking, in order to explain the observation of ${\cal B}(Λ_c^+\to Σ^{*+}η)$. For the dec…
We analyse the four-body $B\rightarrow ϕ(\rightarrow K\bar K)K^*(\rightarrow Kπ)$ decays in the perturbative QCD approach,where the invariant mass of $K\bar K$($Kπ$) system is limited in a window of $\pm 15$ MeV ($\pm150$ MeV) around the $ϕ(K^*(892))$ mass.In addition to the P wave resonances,two important S wave backgrounds in the selected invariant mass region are also accounted for. Angular momentum conservation allows six helicity amplitudes to contribute,including three P waves, two single S waves,and one double S wave. We calculated the branching ratio for each component and found sizabl…
We study the correlation between the Standard Model Higgs decay $h\to γγ$ and $h\to Z γ$ in the Inert Higgs Doublet Model. It is found that these two one-loop-induced decays are positively correlated, with the later channel having slightly smaller branching ratio than the former one. At the Linear Collider, we study the interplay of the off-shell extension of these two amplitudes that contributed significantly to the associated production of the Higgs boson with a photon in the process $e^+ e^- \to γh$ and with an electron in the process $e^-γ\to e^- h$ in the $s$ and $t$ channels respectively…
Future precision measurements of Higgs boson decays will determine the branching fraction for the decay into two photons with a precision at the one percent level. To fully exploit such measurements, equally precise theoretical predictions need to be available. To this end we compute four-loop QCD corrections in the large top quark mass expansion to the Higgs boson--photon form factor, which enter the two-photon decay width at next-to-next-to-next-to-leading order. Furthermore we obtain corrections to the two-photon decay width stemming from the emission of additional gluons, which contribute …
A long-standing puzzle in charm physics is the large difference between the D0 -> K+ K- and D0 -> pi+ pi- decay rates. Recently, the LHCb and CDF collaborations reported a surprisingly large difference between the direct CP asymmetries, Delta A_CP, in these two modes. We show that the two puzzles are naturally related in the Standard Model via s- and d-quark "penguin contractions". Their sum gives rise to Delta A_CP, while their difference contributes to the two branching ratios with opposite sign. Assuming nominal SU(3) breaking, a U-spin fit to the D0 -> K+ pi-, pi+ K-, pi+ pi-, K+ K- decay …
We study the pion decays with intermediate on-shell neutrinos $N$ into two electrons and a muon, $π^{\pm} \to e^{\pm} N \to e^{\pm} e^{\pm} μ^{\mp} ν$. We investigate the branching ratios ${\rm Br}_{\pm} = [Γ(π^- \to e^- e^- μ^+ ν) \pm Γ(π^+ \to e^+e^+μ^-ν)]/Γ(π^- \to {\rm all})$ and the CP asymmetry ratio ${\cal A}_{\rm CP} = {\rm Br}_{-}/{\rm Br}_{+}$ for such decays, in the scenario with two different on-shell neutrinos. If $N$ is Dirac, only the lepton number conserving (LC) decays contribute (LC: $ν= ν_e$ or ${\bar ν}_e$); if $N$ is Majorana, both LC and lepton number violating (LV) decay…
In the littlest Higgs model with T-parity (LHT), the mirror quarks have flavor structures and will contribute to the top quark flavor changing neutral current. In this work, we perform an extensive investigation of the top quark rare three-body decays $t\to cVV (V=γ,Z,g)$ and $t\to cf\bar{f} (f=b,τ,μ,e)$ at one-loop level. Our results show that the branching ratios of $t\to cgg$ and $t\to cb\bar{b}$ could reach $\mathcal {O}(10^{-3})$ in the favorite parameter space of the littlest Higgs model with T-parity, which implies that these decays may be detectable at the LHC or ILC, while for the oth…
We study the {\it CP}-averaged branching fractions and the {\it CP}-violating asymmetries in the pure annihilation decays of $B_s^0 \to a_0^+ a_0^-$ and $B_d^0 \to K_0^{*+} K_0^{*-}$, where $a_0\;[K_0^*]$ denotes the scalar $a_0(980)$ and $a_0(1450)$ [$K_0^*(800) ( {\rm or}\; κ)$ and $K_0^*(1430)$], with the perturbative QCD factorization approach under the assumption of two-quark structure for the $a_0$ and $K_0^*$ states. The numerical results show that the branching ratios of the $B_d^0 \to K_0^{*+} K_0^{*-}$ decays are in the order of $10^{-6}$, while the decay rates of the $B_s^0 \to a_0^…
We calculate the branching ratios and polarization fractions of the $B \to a_1 b_1$ decays in the perturbative QCD(pQCD) approach at leading order, where $a_1$($b_1$) stands for the axial-vector $a_1(1260)[b_1(1235)]$ state. By combining the phenomenological analyses with the perturbative calculations, we find the following results: (a) the large decay rates around $10^{-5}$ to $10^{-6}$ of the $B \to a_1 b_1$ decays dominated by the longitudinal polarization(except for the $B^+ \to b_1^+ a_1^0$ mode) are predicted and basically consistent with those in the QCD factorization(QCDF) within error…
We revisit the radiative decays of the Higgs boson to a fermion pair $h\rightarrow f\bar{f}γ$ where $f$ denotes a fermion in the Standard Model (SM). We include the chirality-flipping diagrams via the Yukawa couplings at the order $\mathcal{O}(y_f^2 α)$, the chirality-conserving contributions via the top-quark loops of the order $\mathcal{O}(y_t^2 α^3)$, and the electroweak loops at the order $\mathcal{O}(α^4)$. The QED correction is about $Q_f^2\times {\cal O}(1\%)$ and contributes to the running of fermion masses at a similar level, which should be taken into account for future precision Hig…
We calculate tree-level contributions to the inclusive rare $\bar B \to X_{s(d)} \, \ell^+\ell^-$ decays. At the partonic level they stem from the five-particle process $b \to s(d) \, q \bar q \, \ell^+\ell^-$, with $q \in \{u,d,s\}$. While for $b \to d$ transitions such five-body final states contribute at the same order in the Wolfenstein expansion compared to the three-body partonic decay, they are CKM suppressed in $b \to s$ decays. In the perturbative expansion, we include all leading-order contributions, as well as partial next-to-leading order QCD and QED effects. In the case of the dif…
Since no direct signs of new physics have been observed so far indirect searches in the Higgs sector have become increasingly important. With the discovered Higgs boson behaving very Standard Model (SM)-like, however, indirect new physics manifestations are in general expected to be small. On the theory side, this makes precision predictions for the Higgs parameters and observables indispensable. In this paper, we provide in the framework of the CP-violating Next-to-Minimal Supersymmetric extension of the SM (NMSSM) the complete next-to-leading order (SUSY-)electroweak corrections to the neutr…
We survey all possible supersymmetric three-body decays of the top quark in the framework of the MSSM and present detailed numerical analyses of the most relevant cases. Although the two-body channels are generally dominant, it is not inconceivable that some or all of our most favourite two-body SUSY candidates could be suppressed. In this event there is still the possibility that some of the available three-body SUSY modes might exhibit a substantial branching fraction and/or carry exotic signatures that would facilitate their identification. Furthermore, in view of the projected inclusive me…
We investigate a model where the dark matter particle is a chiral fermion field charged under a global $U(1)$ symmetry which is assumed to be spontaneously broken, leading to a pseudo-Goldstone boson (PGB). We argue that the dark matter annihilation into PGBs determine the dark matter relic abundance. Besides, we also note that experimental searches for PGBs allow either for a very long lived PGB, with a lifetime much longer than the age of the Universe, or a relatively short lived PGB, with a lifetime shorter than one minute. Hence, two different scenarios arise, producing very different sign…
