The use of QCD in OZI violating radiative decays of vector mesons

The spin parity (J^P) of the hadronic system produced in OZI violating vector decays V → γ + h is analyzed in the lowest order QCD approach. While the predicted rates for 0^± states agree with the data, theoretically unacceptable anomalies occur for even J ≠ 0, P = +1, channels. Experimental consequences are drawn. We argue that the rate for gluon jet emission in V → γ + 2 gluons is substantially smaller than previously stated.     

Zweig rule violating decays of the new particles

The specific decay modes of the new gy particles and their cascade products are considered according to an approximate scheme of sequential pole dominance proposed by Freund and Nambu, which is dictated by the dual model dynamics. Predictions and comparison with available data are presented. While asymptotically free gauge theory can trace the origin of violation of Zweig rule and the smallness of ψ width, it can only give an estimate of the over-all violation of the rule and is not well suited for each decay channel separately. The sequential pole model fulfils this task.     

Lepton-number violating decays of heavy mesons

The experimental observation of lepton-number violating processes would unambiguously indicate the Majorana nature of neutrinos. Various ΔL=2 processes for pseudoscalar meson M ₁ decays to another pseudoscalar meson M ₂ and two charged leptons ? ₁, ? ₂ (\(M_{1}^{+}\rightarrow \ell_{1}^{+}\ell_{2}^{+}M_{2}^{-}\)) have been studied extensively. Extending the existing literature on the studies of these kinds of process, we consider the rare decays of heavy mesons to a vector meson or a pseudoscalar meson. These processes have not been searched for experimentally, while they may have sizable decay rates. We calculate their branching fractions and propose to search for these decay modes in the current and forthcoming experiments, in particular at the LHCb.     

Radiative decays,SU(4), and violations of the OZI rule

Radiative decays of old and new mesons are considered using SU(4) and vector dominance. Good agreement iis found for OZI-allowed decays, and a simple framework for studying OZI violations and their dependence on mass, angular momentum and quark type is established. A few assumptions about this dependence lead to quantitative and qualitative predictions which agree with existing experimental results. In addition, within the framework one can test the sufficiency both of mixing as a source of OZI violations and of the minimum number of gluons in $\text{q}\text{q}$ annihilations.     

The theoretical basis and phenomenology of the OZI rule

No reliable theoretical recipe exists for predicting strengths of OZI-forbidden transitions proceeding via two OZI-allowed transitions like φ→K⁺K^?→?π, π^?p→K⁺K^?n→φφn or π^?p→ηn→φφn. Nonet symmetry, exchange degeneracy and duality suppress such transitions by cancellations between different diagrams. Unpredictable OZI violations are introduced by breaking of these symmetries. Phenomenological analyses of charmonium decays and meson photoproduction establish an emperical topological criterion for classifying some processes as less forbidden and suggest that π^?p→φφn should not be suppressed by a factor of more than three in amplitude. Its observation is not conclusive evidence for new exotic particles.     

Lepton flavour violating heavy Higgs decays within the and their detection at the LHC

Within the νMSSM, a Minimal Supersymmetric neutrino See-saw Model, Lepton Flavour Violating Higgs couplings are strongly enhanced at large tanβ (30), which can lead to BR(H⁰/A⁰→τμ)O(10⁻⁴), for M_H⁰/A⁰160 GeV. Enhancements on the production of Higgs bosons, through the gluon fusion mechanism, gg→H⁰/A⁰, and the associated production channel , whose rates grow with tanβ, as well as the mass degeneracy that occurs between the H⁰ and A⁰ states in this regime, also contribute to further the possibilities to detect a heavy Higgs signal into τμ pairs. We show that the separation of τμ Higgs events from the background at the upcoming CERN Large Hadron Collider could be done for Higgs masses up to about 600 GeV for 300 fb⁻¹ of luminosity, for large tanβ values. However, even with as little as 10 fb⁻¹ one can probe H⁰/A⁰ masses up to 400 GeV or so, if tanβ=60. Altogether, these processes then provide a new Higgs discovery mode as well as an independent test of flavour physics.     

The effect of the location of the new Higgs doublet on the radiative lepton flavor violating decays in the split fermion scenario

We study the branching ratios of the lepton flavor violating processes μ→eγ, τ→eγ and τ→μγ in the split fermion scenario, with the assumption that the new Higgs doublet is restricted to the 4D brane (thin bulk) in one and two extra dimensions, in the framework of the two Higgs doublet model. We observe that the branching ratios are sensitive to the location of the 4D brane and, in the second case, the width of the thin bulk, especially for the μ→eγ decay.     

Study of the OZI selection rule in hadronic processes

In the experiments with LEPTON-F and SPHINX spectrometers the pion-induced charged exchange reactions π- + p → ? + n and π- + p → ω + n at Pπ-=32.5 GeV, as well as proton-induced diffractive reactions p + N → [p?] + N and p + N → [pω] + N at E _p =70 GeV were studied. The comparison of the cross-sections for ? and ω-production in these reactions is used for testing the OZI selection rule in hadronic processes. It has been demonstrated that in pion reactions the ratio of the yields of ? and ω-mesons R(?/ω) = (3 ± 1) · 10^?3 is in a good agreement with naive quark model prediction based on the mixing in vector meson nonet and on the OZI rule (R(?/ω)ozi = tg ²Δθ _V ? 4 · 10^?3). At the same time in proton reactions the effective ratio of ? and ω yields is ～ (4 ÷ 7) · 10^-2, i.e. a strong violation of the OZI rule is observed in proton-nucleon interactions. This violation can be in favor of possible existence of some exotic ss? component in the quark structure of protons.     

CP violating asymmetries in the neutral kaon decays

We study the time dependence of the integrated asymmetries in strangeness of kaons in the decays in two and three pions and in two photons with the purpose of disentangling theCP violating effects in the decay amplitudes from the ones related to the mass matrix. We find two cases where they are not reduced by the I=1/2 rule or hidden byCP violation in the mass matrix, namely the strangeness-energy correlation of the charged pions in the prompt decay ( _S ) in ^+-0, and the decays in two photons. The semileptonic decays are also briefly studied.     

On the radiative decays of pions

A critical analysis of the theory of the radiative decays π → ?νγ (?: electron or muon) is given. Earlier results are corrected through a consistent application of gauge invariance and low-energy theorems. Predictions of specific models for the axial-vector form factor are discussed. The paper concludes with remarks on the relate$\text{π →}\text{e}\text{ν}\text{e}\text{e}$.     

A nonperturbative treatment of radiative decays and the relativistic kinetic energy in heavy quarkonia

Using a “regularized potential” we solve the Schrödinger equation including all spin dependent interactions nonperturbatively and calculate the radiative decays of heavy quarkonia. The influence ofS-D mixing due to the tensor term is discussed. Applying the variational approach we investigate the influence of the relativistic kinetic energy on the bound state masses.     

Weak radiative decays of baryons

Using recent experimental baryon weak radiative decay data for the fiveB→B′γ decays, we employ the pole model self-consistently to extract the reduced matrix elements 〈B′|H _w|B〉. The resulting pattern is compatible with weak pion decaysB→B′π and also with the quark model.