The surprising nonleptonic decays

Recent experiments onD-meson decays necessitate a revision of the standard theoretical model for weak decays. In this paper we argue that the presence of gluons in hadrons as required by local color gauge-invariance of Quantum Chromodynamics vitiates, in particular, two assumptions previously made:

1. color suppression factors in amplitudes for weak decays like \(D^0 \to \bar K^0 \pi ^0 \) ,
2. helicity suppression of two-quark interactions in weak decays.

A formula for estimating inclusive rates of mesons decaying via two-quark interactions is derived. Estimates for decay rates and branching ratios of several interesting decays of charmed hadrons are given. In particular, we obtain lifetime estimates forD ⁰,D ⁺, andF ⁺, and we predict the branching ratio for Cabibbo-suppressed decays ofD ⁺ to be of order 0.3 rather than of order tan²Θ _c as expected within the conventional model for weak decays.B-meson decays, which would provide an additional test of our scheme, are briefly discussed. Furthermore we point out that our approach sheds new light on the old problem of strongly enhanced |ΔI|=1/2 amplitudes in nonleptonic decays of strange particles.     

Branching ratios for the decays of Ψ(3770) and ϒ(10580) mesons to a pair of light hadrons

The branching ratios for the exclusive decays of the heavy quarkonia Ψ(3770) and ?(10580) to a pair of light mesons [π ⁺ π ^-, $K\bar K$ , ρ(ω)π, ρ(ω)η, ρ(ω)η’, $K^* \bar K$ +c.c, ρ ⁺ ρ ^-, and $K^* \bar K^* $ ] and the branching ratios for the decays Ψ(3770) → J/Ψ + P(P = π ⁰, η) and ?(10580) → ?(1S) + P(P = π ⁰,η,η′), which involve a heavy quarkonium in the final state, are calculated with allowance for new data on the width of the D*^±(2010) meson and the mass differences between the charged and neutral beauty mesons (B ^±, on one hand, and B ⁰ and $\bar B^0 $ , on the other hand). The calculations are based on the model where the Okubo-Zweig-Iizuka rule is dynamically violated owing to the intermediate state $D\bar D (B\bar B)$ in the case of the Ψ(3770) [?(10580)] meson. The inclusive annihilation of Ψ(3770) and ?(10580) mesons to light hadrons is discussed.     

The process e + e − → bb̅W + W − at the next linear collider in the Minimal Supersymmetric Standard Model

The complete matrix element for e ⁺ e^? → bb?W⁺ W^? is computed at tree-level within the Minimal Supersymmetric Standard Model. Rates of interest to phenomenological analyses at the Next Linear Collider are given. In particular, we study:

• ? tt? production and decay tt? →(bW ⁺)(b?W ^?)
• ? ZH production followed by Z → bb? and H → W ⁺ W^?
• ? AH production followed by A→ bb? and H → W ⁺ W^?
• ? hW ⁺ W^? production followed by h→ bb?.

Top and Higgs finite width effects are included, as well as all those of the irreducible backgrounds.     

Dynamical enhanced electron emission and discharges at contaminated surfaces

Broad-area electrodes show electron emission already at electric field strengthsF≈10⁷ V/m. This enhanced field emission (EFE) occurs only for contaminated surfaces. EFE is accompanied by photon emission and gas desorption yielding finally discharges. EFE is caused by dust and contaminants initiating the following effects:

an electron is stochastically emitted in a trigger zone

the electron gains energyΔE?eΔxF ^*

which excites electronic states

which relax by the emission of electrons, photons, and atoms

where the positive charges left behind enhanceF ^*=βF (β?1) initiating so an electron avalanche, i.e., a high conductivity channel. Because of charge migration and neutralization, this avalanche has a life time. This pulsating EFE is accompanied by light emission and gas desorption yielding finally a gas cloud and a discharge.

The pulsating, self-sustained EFE has the same root as:

the enhanced secondary emission found first by Malter

the conductivity switching exhibited by thin (≈ 1 μm) layers of semiconductors or insulators

the normal cathode fall and

the firing-wave instability in neurodynamics.

     

SIMS and flash desorption studies of nickel oxygen interaction

O₂ exposure of polycrystalline nickel at 300 K results in characteristics changes of secondary ion emission. These can be described by a model which is in good agreement with corresponding LEED, AES, XPS, and ΔΦ results of other authors. According to this model, oxygen can be bonded on Ni in at least five different phases:

1. chemisorption, indicated by a rapid increase of Ni⁺, Ni ₂ ⁺ , and Ni₂O⁺ (≦5 L);
2. a rearranged chemisorption layer, characterized by a drastic decrease of Ni⁺, Ni ₂ ⁺ , and Ni₂O⁺ (5–15 L);
3. nickel oxide (NiO) responsible for a strong NiO^?- and NiO ₂ ^? -emission (≦40 L);
4. oxygen on top of this NiO layer, producing a final increase of Ni⁺ and NiO⁺ and a O₂-flash signal at 400 K (>40 L);
5. bulk dissolved oxygen in thermal equilibrium with a chemisorption layer (after several exposure/heating cycles).

During ion bombardment of a 100 L O₂ exposed Ni surface these different binding states occur in a reversed order of succession. O₂-flash signals at 400 and 1100 K, related to drastic changes in secondary ion emission at 400, 700, and 1100 K, reflect the disappearance of various oxygen binding states. The exchange between different oxygen phases was studied by¹⁶O₂/¹⁸O₂ isotope experiments.     

Colour-exotic constitutent quarks and hadron spectroscopy

Hypothetical colour-exotic constituent (or dressed) quarks are discussed. It is shown that the data on the excited baryons withJ ^P =1/2⁺, 3/2⁺ and excited mesons withJ ^P =0^?, 1^? are in a reasonable agreement with the hypothesis of the existence of colour-exotic quark in the colour state \(\bar 6\) .     

Spin forces in mesons made up of quarks of different mass

With the help of a variational method we apply the standard Coulomb + Linear potential to the analysis of mesons constructed from quarks of different mass. Fine and hyperfine splittings are discussed, with particular emphasis on their asymptotic behaviour. Striking differences in this behaviour are predicted to occur compared with the case of mesons built up from equal mass quarks, with the spin-orbit mixing force playing here a fundamental role. Such predictions may be tested within the bottom \((b\bar u)\) meson family. Our considerations are also extended to the strange and charmed mesons. Our model favours ak(O⁺) below theK ^* (1.430), and predicts a partial inversion in the ordering of theP-wave states of the charmed mesons \((c\bar u)\) .     

Unbounded derivations ofC*-algebras II

It is demonstrated that a closed symmetric derivation δ of aC?-algebra \(\mathfrak{A}\) generates a strongly continuous one-parameter group of automorphisms of aC?-algebra \(\mathfrak{A}\) if and only if, it satisfies one of the following three conditions

1. (αδ+1)(D(δ))= \(\mathfrak{A}\) , α∈?\{0}.
2. δ possesses a dense set of analytic elements.
3. δ possesses a dense set of geometric elements.

Together with one of the following two conditions

1. ∥(αδ+1)(A)∥≧∥A∥, α∈IR,A∈D(δ).
2. If α∈IR andA∈D(δ) then (αδ+1)(A)≧0 impliesA≧0.

Other characterizations are given in terms of invariant states and the invariance ofD(δ) under the square root operation of positive elements.     

Production properties ofD 0,D +,D *+ andD s + in 230 GeV/cπ − andK −-Cu interactions

We have studied the hadronic production of charmed mesons in the NA 32 experiment at CERN. A special trigger together with a high resolution vertex detector consisting of charge coupled devices and silicon microstrip detectors allowed the selection of very clean samples of charmed mesons. We have collected 852 fully reconstructed decays: 60D _s ⁺ →K ⁺ K ^?π⁺, 543D°→K ^?π⁺ andK ^?π⁺π^?π⁺ as well as 249D ⁺→K ^?π⁺π⁺ (or charge conjugate). 147 mesons out of our \({{D^0 } \mathord{\left/ {\vphantom {{D^0 } {\bar D^0 }}} \right. \kern-0em} {\bar D^0 }}\) sample were produced via chargedD ^* state. For all charmed mesons we determine the total production cross-section and study thex _F andp _t ² distributions.     

37 Years with the light scalar mesons. The learned lessons

Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the σ(600) meson. We show that the kaon loop mechanism of the ? radiative decays, ratified by experiment, is four-quark transition and points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor qq? mesons that are produced via two-quark transitions γγ → qq?. We study the mechanism of production of the light scalar mesons in the D _s ⁺ → π⁺π^? e ⁺ν decays: D _s ⁺ → ss?e ⁺ν → [σ(600) + f ₀(980)]e ⁺ν → π⁺π^? e ⁺ν, and compare it with the mechanism of production of the light pseudoscalar mesons in the D _s ⁺ → (η/η′)e ⁺ν decays: D _s ⁺ → ss?e ⁺ν → (η/η′)e ⁺ν. As a result we find support to four-quark nature of light scalars. In the end, we outline the future research program.     

High spin mesons and zweig-superconvergence relations

The basic and simplest aspects of duality are used to deduce some decay widths ofJ ^P =3^?, 4⁺... mesons in agreement with available data. This may be of interest when investigating the nature of these mesons and, in particular, whether they are conventional \(q\bar q\) -systems or not.     

Jets fromQ \bar Q P waves

We discuss angular distributions and some kinematic features for jets originating from the decay of orbitally excitedQ \(\bar Q\) states. These can be produced ine ⁺ e ^? storage rings via the radiative decay of the first radial excitedQ \(\bar Q\) vector meson. We further present the complete and explicit angular distribution for the cascade decaye ⁺ e ^? → 2³ S ₁ →γ ₁+³ P _j,³ P _j →γ ₂+1³ S ₁, 1³ S ₁ →μ ⁺ μ ^? in all casesj=0, 1, 2. These distributions serve as a test of the spinj of intermediate states inQ \(\bar Q\) systems. By the photon—gluon analogy they can successfully be applied to the jet process, too.     

A candidate for a four-quark vector-meson?

Previous claims for the existence of vector mesons with masses in the vicinity of 1100 MeV and 1300 MeV are reconsidered in the light of recent developments in the analysis and interpretation ofe ⁺ e ^? annihilation and diffractive photoproduction data. It is shown that these states are compatible with present evidence and can be incorporated in an extended mixing scheme of conventional \(q\bar q\) with unconventional \(qq\bar q \bar q\) states.     

Final state interaction effects in the B + → D + K 0 decay

The exclusive decay of B ⁺ → D ⁺ K ⁰ is calculated by the QCD factorization method (QCDF) and final state interaction (FSI). First, the B ⁺ → D ⁺ K ⁰ decay is calculated via QCDF method. The result that is found by using the QCDF method is less than the experimental result. So FSI is considered to solve the B ⁺ → D ⁺ K ⁰ decay. For this decay, the D _s ⁺ π⁰, D _s ⁺ *ρ⁰, D _s ⁺ *? via the exchange of \(\bar K^0\) , \(\bar K^{0*} \) , D ^?, and D ^?* mesons are chosen for the intermediate states. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on η as the phenomenological parameter. The range of this parameter is selected from 2 to 2.4. It is found that if η = 2.4 is selected, the numbers of the branching ratio are placed in the experimental range. The experimental branching ratio of this decay is less than 2.9 × 10^?6 and our results calculated by QCDF and FSI are (0.16 ± 0.04) × 10^?6 and (2.8 ± 0.09) × 10^?6, respectively.     

Doubly Charmed Exotic Mesons

We discuss the mass spectrum of doubly charmed mesons as hadronic molecules composed by D and D^* meson. Considering the heavy quark symmetry and chiral symmetry, we introduce the one-boson ( ${\pi , \rho , \omega}$ ) exchange potential between D and D^* meson. For all possible quantum numbers I(J ^P ) with isospin I, total angular momentum J( ≤ 2) and parity P, we solve the fully coupled channel Schrödinger equation. We find that in many quantum numbers the bound and resonant states composed by D or D^* meson can exist near the DD, DD^* and D^*D^* thresholds.     

Tests of discrete symmetries with the neutral kaon system at the KLOE and KLOE-2 experiments

The KLOE-2 experiment continues and extends the program of its predecessor KLOE in the field of discrete symmetry tests with the K meson system, among other studies which comprise light meson spectroscopy, dark matter searches and γγ physics. Together, KLOE and KLOE-2 have recorded the largest sample (almost 8 fb^??1) of e⁺e^? collisions at the energy equal to ? meson mass, amounting to 2.4 × 10¹⁰ of produced ? mesons. We report on the latest results and ongoing analyses of KLOE and KLOE-2 concerning discrete symmetry tests and measurements of symmetry-violating observables. A measurement of the CPT violation sensitive asymmetry in semileptonic decays of K˙S with 1.7 fb^??1 of KLOE data will be presented, which improves the sensitivity w.r.t. previous measurements about twice. Moreover, status of direct tests of T and CPT in transitions of neutral kaons performed with the ? →K˙SK˙L → πeν, 3π⁰(2π) processes will be reported, followed by the search of the CP-violating decay K˙S → 3π⁰ using the data recently acquired by KLOE-2.     

The(cc) - (\overline {cc} ) (diquark-antidiquark) states ine + e − annihilation

The mass spectrum and decay modes of the \((cc) - (\overline {cc} )\) states are estimated in a quark-gluon model. We argue that the peculiar resonance-like structures ofR(e ⁺ e ^? →hadrons) for \(\sqrt s = 6 - 7\) GeV may be due to production of theP-wave \((cc) - (\overline {cc} )\) states. They are predicted to lie in the range 6.4–6.8 GeV and mainly decay into charmend mesons.     

Radiative decays and quark content of f 0(980) and φ(1020)

The quark structure of φ(1020) and f ₀(980) is studied on the basis of data on the radiative decays φ(1020) → γπ ⁰, γη, γη′, γ a ₀(980), γ f ₀(980) and f ₀(980) → γγ. The partial widths are calculated under the assumption that all the mesons under consideration are $\bar qq$ states: φ(1020) is a dominantly $s\bar s$ state ( $\eta ' = n\bar nsin\theta + s\bar scos\theta $ component contributes not more than 1%); η, η′, and π ⁰ are standard $q\bar q$ states, $\eta = n\bar ncos\theta - s\bar ssin\theta $ and $\eta ' = n\bar nsin\theta + s\bar scos\theta $ with θ?37°; and f ₀(980) is a e5 meson with the flavor wave function $n\bar ncos\varphi + s\bar ssin\varphi $ . The transition φ → γπ ⁰ specifies the admixture of the $n\bar n$ component in the φ meson: it is on the order of 0.5%. We argue that this order of $n\bar n$ value does not contradict data on the decay φ(1020) → γ a ₀(980). The partial widths calculated for the decays φ → γη, γη? are in reasonable agreement with experimental data. The measured branching-ratio value Br(φ→γf ₀(980))=(3.4±0.4 _?0.5 ^+1.5 ×10^?4) requires 25°≤|?|≤90°. For the decay f ₀(980) → γγ, the agreement with data, Γ(f ₀(980) → γγ)=0.28 _?0.13 ^+0.09 keV, is attained at either ?=85°±8° or ?=?46°±8°. A simultaneous analysis of the decays φ(1020) → γ f ₀(980) and f ₀(980) → γγ favors the solution with the negative mixing angle of ?=?48°±6°, setting f ₀(980) very close to the flavor octet (? _octet=±54.7°).     

Effects of Final State Interactions in Pure Annihilation Decay of B^{0}_{s}\rightarrow\pi^{0}\pi^{0}

We investigate the effects of final state interactions (FSI) contributions in the nonleptonic two body $B^{0}_{s} \rightarrow \pi^{0}\pi^{0}$ decay. The short distance interaction amplitude is calculated by using the annihilation diagrams and a tiny branching ratio is obtained, then the long distance amplitude is considered and calculated within FSI effects. For contributions of FSI, the ρ ⁰ ρ ⁰, π ⁺ π ^?(ρ ⁺ ρ ^?), K ⁺ K ^?(K ^+? K ^??) and $K^{0}\bar{K}^{0}(K^{0*}\bar{K}^{0*})$ are produced for intermediate states, in this case the π ⁰, π ^?(ρ ^?), K ^?(?) and $\bar{K}^{0(*)}$ mesons are exchanged. The absorptive part of the diagrams is directly calculated and the dispersive part of the rescattering amplitude can be obtained from the absorptive part via the dispersion relation. The imaginary and real parts of the amplitudes are summed over all intermediate states. The predicted branching ratio of $B^{0}_{s} \rightarrow \pi^{0}\pi^{0}$ is 0.69×10^?8 in the absence of FSI effects and it becomes 1.86×10^?4 when FSI contributions are taken into account, while the experimental result is less than 2.1×10^?4.