The \phi \to \gamma (a_0 (980) + f_0 (980)) \to \gamma {\rm K}\bar {\rm K} decays

We study the decay φ → γK ⁺ K ^? taking into account the scalar meson production φ → γ(a ₀+f ₀ → γK ⁺ K ^? and the final-state radiation. We note that the relative sign between the final-state radiation amplitude and the scalar-meson production amplitude is fixed in the K ⁺ K ^? loop model which describes data on the φ → γf ₀ → γππ and φ → γa ₀ → γπη decays. As consequence, this model predicts the definite interference between the final-state radiation and the scalar resonance production amplitudes. We calculate the mass spectra of the φ → γK ⁺ K ^? decay and the differential cross sections for $e^ + e^ - \to \phi \to \gamma {\rm K}^0 \bar {\rm K}^0 $ reactions.     

Evidence for the Bφ decay mode of the ω(1670)

Backward production of ω(1670) is observed in the reactions K^?p→φ⁺φ^?ω⁰Λ⁰ and K^?p→φ⁺φ^?φ⁰φ⁰ for |U'_Λ|<1.0 GeV². The cross section for the ω(1670) →φ⁺φ^?ω⁰ decay mode is 1.90±0.35 μb for 8.25 GeV/c incident K^?. Evidence is presented for the importance of the sequential decay, ω(1670) → Bφ → ωφφ with a branching ratio ω(1670) → Bφ/all ω(1670) → ωφφ=1.0±_0.25^0.00.     

Analysis of the φ → γπη and φ → γπ 0 π 0 decays

We study interference patterns in the φ → (γa ₀+π ⁰ ρ) → γπη and φ → (γf ₀+π ⁰ ρ) → γπ ⁰ π ⁰ reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the π ⁰ η spectrum in the decay φ → γπη everywhere over the energy region and does not distort the π ⁰ π ⁰ spectrum in the decay φ → γπ ⁰ π ⁰ in the wide region of the π ⁰ π ⁰-system invariant mass, π ^ππ > 670 MeV, or when the photon energy is less than 300 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are reasonable arguments in favor of the one-loop mechanism φ → K ⁺ K ^? → γa ₀ and φ → K ⁺ K ^? → γf ₀. We also discuss distinctions between the four-quark, molecular, and two-quark models and argue that the Novosibirsk data give evidence in favor of the four-quark nature of the scalar a ₀(980) and f ₀(980) mesons.     

Mean work functions effective for negative-ionic, electronic and positive-ionic emissions from polycrystalline surfaces

To elucidate the thermionic property of polycrystalline surfaces, a further study is made on the mean work functions (φ⁻, φ^e and φ⁺) effective for negative-ionic, electronic and positive-ionic emissions. Comparison between theoretical analyses and experimental data yields the conclusions as follows. (1) The equation of φ⁻ = φ^e holds always with both mono- and polycrystalline surfaces. (2) The relation of φ⁻ = φ^e < φ⁺ applies to polycrystalline surfaces because they bear the thermionic contrast (Δφ^* ≡ φ⁺ − φ^e > 0). (3) The value of Δφ^* ranges from ∼0.4 to 0.9 eV depending upon the surface species of polycrystalline metals (e.g., W, Re and Pt), whilst Δφ^* = 0 for monocrystalline surfaces. (4) When the degree of monocrystallization (δ_m) is less than ∼50%, the theoretical value of Δφ^* is virtually independent of δ_m and agrees well with experimental data, nearly the same within ±0.1 eV among the so-called “polycrystalline” surfaces of W. (5) As δ_m increases beyond ∼80 up to 100%, Δφ^* decreases rapidly down to 0 eV, showing again a good agreement between theory and experiment. (6) Our theoretical model is valid in evaluating the effective mean work functions, irrespective of the range of δ_m.     

Theoretical evaluation of the effective work functions for positive-ionic and electronic emissions from polycrystalline metal surfaces

Effective work functions (φ⁺ and φ^e) for positive-ionic and electronic emissions from polycrystalline metals of Nb, Mo, Ta, W and Ir are calculated according to our theoretical model by using those published data on both fractional surface area (F_i) and local work function (φ_i) of each metal surface composed of several patchy faces (1, 2, …, i). Comparison between the theoretical values thus obtained and those experimental data published to date yields the conclusions as follows. (1) With a slight error of less than ∼0.1 eV, the value of φ^e calculated with each of the metals is in fair or good agreement with that determined by experiment. (2) Such agreement is found also with φ⁺ for W. (3) In a typical case of W, where the degree of monocrystallization (δ_m) corresponding to the largest among the values of F_i is less than ∼0.5, the thermionic contrast (Δφ* ≡ φ⁺ − φ^e) is found again to be nearly equal to both theoretical and experimental values reported previously. (4) Each of the five metals shows that Δφ* at δ_m = 0.68-0.95 is smaller than Δφ* at δ_m < 0.5. (5) This result strongly supports our theoretical prediction that Δφ* decreases gradually to zero as δ_m increases beyond ∼0.5 up to ∼1. (6) Particularly, such a surface which has δ_m ≥ 0.96 exhibits Δφ* ≈ 0, apparently equivalent to the so-called “monocrystalline surface (δ_m = 1)”. These results lead to the conclusion that our theoretical model is valid for evaluating the effective work functions probably with a slight error of less than ∼0.1 eV, irrespective of both the surface species and the range of δ_m. In addition, our simple model makes it possible to analyze the mechanism of change in φ⁺ and φ^e according to the change in surface characters of both φ_i and F_i.     

A study of the neutrino production of <Emphasis Type="Italic">φ</Emphasis> and <Emphasis Type="Italic">D</Emphasis><Stack><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript><Superscript>+</Superscript></Stack> mesons

The charged current neutrino production of φ and D _s ⁺ mesons is studied, using the data obtained with the SKAT bubble chamber exposed to the Serpukhov accelerator neutrino beam. It is found that the φ production occurs predominantly in the forward hemisphere of the hadronic c.m.s. (at x _F > 0, x _F being the Feynman variable), with the mean yield strongly exceeding the expected yield of directly produced φ mesons and varying from 〈n _φ(x _F s 0)〉 = (0.92 ± 0.34) × 10^?2 at W > 2 GeV up to (1.23 ± 0.53) × 10^?2 at W > 2.6 GeV and (1.44 ± 0.69) × 10^?2 at W > 2.9 GeV, W being the invariant mass of the hadronic system. For the first time, the inclusive yield of leading D _s ⁺ mesons carrying more than z = 0.85 of the current c-quark energy is estimated: 〈n _{D s} ⁺ (z > 0.85, W > 2.9 GeV)〉 = (6.64 ± 1.91) × 10^?2. It is shown that the shape of measured φ meson differential spectrum on xF is reproduced by that expected from the D _s ⁺ → φX decays. An indication was obtained that this expected spectrum underestimates the measured φ yield.     

Cabibbo Universality,renormalization, and the Z vector boson mass

Using the most recent data on the ft-values of the 0⁺ → 0⁺ decays ¹⁴O, ^26mAl and ³⁵Cl, the hyperon β-decays, and the K_e3⁺ rate, we determine the following limits (95% confidence level): Cabibbo angle sin θ > 0.226, intermediate vector boson mass M_Z > 25 Gev (for four quarks with integral charges) or M_Z > 110 GeV (three colored quartets), K_e3⁺ form factor $\text{?}{}_{\mathrm{+}}\text{(0) < 0.98}$.     

Associated production of intermediate-mass Higgs particle with a large-pT jet at SSC energy

We calculate the higher-order Higgs particle production process gg→gH for a large top-quark mass (2m_t > m_H). We compute the resulting associated cross section for intermediate-mass Higgs particle (m_W<m_H<2m_W) at SSC, followed by its dominant decay mode into a bottom-quark pair. At large p_T the cross section becomes comparable to that of the QCD background while remaining sufficiently large for detection at SSC.     

B → Kμ+μ-: Light Higgs and fourth generation

We examine the current limit on the branching ratio for B → Kμ⁺μ^- and the theoretical predictions for B → KH → Kμ⁺μ^- in three- and four-generation models. It is shown that for a heavy top quark m_t≳60 GeV a light Higgs, m_H ⩽3.5 GeV, is disfavoured in a three-generation model. We also find that the existence of a light Higgs constrains the four-generation model quite strongly through the above process.     

Search forββ decay of76Ge to the excited states in76Se

Lower limits on the half-life of theββ(2v+0v) decay of⁷⁶Ge to the excited states in⁷⁶Se have been obtained using the results of low-background measurements with a HPGe detector surrounded by passive germanium shielding: T_1/2(0⁺ → 2 ₁ ⁺ ) >1.1 · 10²¹ y, T_1/2(0⁺ → 0 ₁ ⁺ ) > 1.7 · 10²¹ y, T_1/2(0⁺ → 2^2/+) > 1.4 ·10²¹ y.     

The evaluation of the branching ratios of the decays φ(1020)→2π<Superscript>+</Superscript>2π<Superscript>−</Superscript>π<Superscript>0</Superscript>, π<Superscript>+</Superscript>π<Superscript>−</Superscript>3π<Superscript>0</Superscript>

Combining the Okubo-Zweig-Iizuka rule in the decay φ→ρπ→π⁺π^?π⁰ with the ρ→4π decay amplitudes, we calculate the φ→2π⁺2π^?π⁰ and φ→π⁺π^?3π⁰ ones. The partial widths of the above φ decays are evaluated, and the excitation curves in e⁺e^? annihilation are obtained, assuming reasonable particular relations among the parameters characterizing the anomalous terms of the HLS Lagrangian. The evaluated branching ratios B_φ→π⁺_π^?_3π⁰ ≈ 2 × 10^?7 and B_φ→2π⁺_2π^?_π⁰ ≈ 7 × 10^?7 are such that, with the luminosity L=500 pb^?1 attained at DAΦNE φ factory, one may already possess about 1685 events of the decays φ→5π.     

Baryon wave functions and nucleon decay

We apply to nucleon decay the knowledge about the short-distance structure of baryon wave functions gleaned from QCD form factor calculations nd the $\text{J}\text{gY →}\text{p}\text{?}\text{p}$ decay rate. We review the uncertainties arising when current algebra and PCAC are used to relate $\text{N}\text{→}\text{?}\text{+}$ meson decay rates to 〈0|qqq|N〉 matrix elements. We show that the relevant matrix elements are not directly related to those of the leading twist operators “measured” in conventional high momentum transfer physics, but argue for an indirect based on models that fit both form factor and $\text{J}\text{Ψ}$ decay data. We use these inputs to calculate the p → e⁺π⁰ decay rate in minimal SU(5) and other grand unified theories (GUTs) for a specified value of the heavy vector boson mass m_X. Our results combined with the recent experimental lower limit on this mode indicate that m_X > 2 × 10¹⁵ GeV in the minimal SU(5) GUT, and we derive analogous bounds for supersymmetric GUTs. Our calculated lifetime for a given value of m_X is considerably shorter than previous estimates made using non-relativistic SU(6) or the bag model, a difference traceable to the different normalizations of 2 and 3 quark wave functions at short distances.     

Familon emissivity of dense e − e + plasma in an external magnetic field

Emission of a familon due to the processes e ^? → e ^?+φ and e ^? → μ ^?+φ by dense magnetized plasma is analyzed as a possible mechanism of energy and momentum losses by astrophysical objects. The field-induced effective familon-photon coupling in the familon-emission process is taken into account. The contribution of these processes to the familon emissivity of a magnetized plasma in a supernova explosion is calculated. It is shown that there is asymmetry of familon emission in the process e ^? → μ ^?+φ.     

Search for rare φ decays in π+π−γ final state

A search for φ radiative decays has been performed using a data sample of about 2.0 million φ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e⁺e⁻→π⁺π⁻γ events the following results were obtained:B(φ→f₀(980)γ)<1×10⁻⁴ for destructive andB(φ→f₀(980)γ)<7×10⁻⁴ for constructive interference with the Bremsstrahlung process respectively,B(φ→γ→π⁺π⁻γ)<3×10⁻⁵ for E_γ>20 MeV,B(φ→ργ)<7×10⁻⁴. From the selected e⁺e⁻→μ⁺μ⁻γ eventsB(φ→μ⁺μ⁻γ)=(2.3±1.0)×10⁻⁵ has been obtained for E_γ>20 MeV. The upper limit on the P,CP-violating decay η→π⁺π⁻ has also been placed:B(η→π⁺π⁻)<9×10⁻⁴. All upper limits are at 90% C.L.     

Electron theory of inverse isotope effect in superconducting PdHx system

From the viewpoint of electron theory of cohesion, it is shown that anharmonic vibration of H(D) atom in PdH_x(PdD_x) alloy gives rise to an isotope effect such that φ_H ≡ m_Hω²_H > φ_D ≡ m_Dω²_D which is the basis to explain the inverse isotope effect in superconducting transition temperature of these systems in contradiction to the expectation from BCS theory.     

Geometry of the effective Majorana neutrino mass in the 0νββ decay

The neutrinoless double-beta (0νββ) decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass <m>_ee. We put forward a novel ‘coupling-rod’ diagram to describe <m>_ee in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on <m>_ee are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of |<m>_ee|. It remains usable even if there is a kind of new physics contributing to <m>_ee, and it can also be extended to describe the effective Majorana masses <m>_eμ, <m>_eτ, <m>_μμ, <m>_μτ and <m>_ττ which may appear in some other lepton-number violating processes.     

A measurement of Kevγ+ decay

The decay K⁺ → e⁺vγ has been observed. In a counter experiment at CERN, 56 events of this type have been identified by detection of a γ with an energy > 100 MeV and of an e⁺ with an energy between 236 MeV and the maximum e⁺ energy, 247 MeV. The angle between γ and e⁺ was > 120°. Thus, the experiment was sensitive only to the structure decay (SD) term proportional to the squared sum of vector- and axialvector amplitudes, |ν_K + a_K|², corresponding to the emission of right handed γ. We find Δ₊(SD)/Δ(K_e2) = 1.05_?0.30^+0.25 and Δ_(SD) < 85 (90% CL). Δ₊ is in agreement with theoretical predictions.     

Higgs boson searches at the Tevatron

This article reviews the Higgs searches at the Tevatron, as presented over the summer of 2012; both standard model (SM) and beyond the standard model (BSM) results are discussed as detailed (arXiv: 1207.0449; Phys. Rev. Lett., 2012, 109: 071804; Phys. Rev. D, 2012, 85: 032005). We discuss the combination of searches by the CDF and D0 Collaborations for the standard model Higgs boson in the mass range 100–200 GeV/c ² produced in the the gg → H, WH, ZH, t{ie27-1}H, and vector boson fusion production modes, and decaying in the H → b{ie27-2}, H → W ⁺ W ^?, H → ZZ, H → τ ⁺ τ ^?, and H → γγ modes. The data, collected at the Fermilab Tevatron collider in p{ie27-3} collisions at {ie27-4} TeV, correspond to integrated luminosities of up to 10 fb^?1. In the absence of signal, we expect to exclude the regions 100<m _H < 120 GeV/c ² and 139<m _H < 184 GeV/c ². We exclude, at the 95% C.L., two regions: 100<m _H < 103 GeV/c ², and 147<m _H < 180 GeV/c ². We observe a significant excess of events in the mass range between 115 and 140 GeV/c ². The local significance corresponds to 3.0 standard deviations at m _H = 120 GeV/c ²; the global significance (incorporating the look-elsewhere effect) for such an excess anywhere in the full mass range investigated is approximately 2.5 standard deviations. Furthermore, we separately combine searches for H → b{ie27-5}, H → W+W ^? and H → γγ. We find that the excess is concentrated in the H → b{ie27-6} channel, appearing in the searches over a broad range of m _H ; the maximum local significance of 3.3 standard deviations corresponds to a global significance of approximately 3.1 standard deviations. The observed signal strengths in all channels are consistent with the expectation for a standard model Higgs boson at m _H = 125 GeV/c ². The production of neutral Higgs bosons in association with b-quarks can be significantly enhanced in various beyond the standard model scenarios, including Supersymmetry. The recent combination of such searches from the two collaborations is discussed.     

Crossing relations for deep-inelastic and annihilation processes

We calculate in a model field theory [φ³]_σ the structure functions $\text{F}\text{?}\text{(ω), F(ω)}$ for the processes e⁺+e^?→h+X and e^?+h→e^?+X in the next to leading logarithm approximation. We find that $\text{F}\text{(ω) and F(ω)}$ satisfy the analytic continuation relation but not the Gribov-Lipatov reciprocity relation.