Prediction of Re ɛ fromK 13 decays in an extended cabibbo model

With the help of an extended Cabibbo model for the weak hadronic vector current which includes the 10 and ¯10 representations to account for possibleΔS=-ΔQ transitions, a prediction is made for the quantity (1-¦x¦²)/¦1?x¦² wherex=A(K⁰→π^üe^?¯v)/A(¯K⁰→π^üe^?¯v) using the experimental branching ratio Γ(K^?→ π⁰e^?¯v/Γ(K _L ⁰ →π^üe^?¯v). From the known charge asymmetry in the decay of the long lived kaon one then obtains Re?.     

Limits on the couplings of ϱ′ (1300 Me) and rhov;″ (1700 MeV) to the photon and to the (ππ) system

The analysis of the reaction e⁺e^?→π⁺π^? measured at the e⁺e^? colliding beam machine ADONE shows that, if ?′ and ?″ exist, the cross sections compare as follows (taking the ? as the reference point): $\text{σ(}\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}\text{→ ? → π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{)}$: σ(e⁺e^? → ?′ → π⁺π^?): σ(e⁺e^? → ?″ → π⁺π^?) = 1: (7 ± 4) × 10^?3: (1 ± 5) × 10^?4. The square of the product of their couplings to the photon (γ_?) and the γγ system (g_?ππ) are derived.     

Determination of the radiative widths of the η′ and A2 from two-photon exchange production

From the two-photon exchange processes e⁺e^? → e⁺e^?η' (958) → e⁺e^??⁰γ and e⁺e^? → e⁺e^?A₂ (1310) → e⁺e^?π⁺π^?π⁰ observed using the CELLO detector at PETRA the radiative widths of the η' and A₂ have been determined with the results: Γ_γγ(η') = 5.4 ± 1.0[stat.] ± 0.7[syst.] keV; Γ_γγ(A₂) = 0.59 ± 0.14[stat.] _?0.08^+0.31[syst.] keV.     

Probing the mesonic structure of the nucleon by means of exclusive quasielastic pion knockout in (e, e′π) reactions at high energies

By including the Z diagram in an analysis performed in the laboratory frame (instantaneous form of dynamics), the notion of quasielastic pion knockout by protons and electrons [(p, 2p) and (e, e′p) reactions treated in terms of the relevant pole diagrams] is generalized to the relativistic case where a meson is quasielastically knocked out of a nucleon by an electron having an energy of a few GeV. The concept of the wave function is introduced for the pion (and for other mesons), and its relation to the vertex constant G _πNN and the vertex function g _πNN(k ²) is indicated. The spectroscopic factor S _N ^B? is defined as the normalization of the wave function for the meson ?. It is shown by two methods that, under the kinematical conditions of quasielastic knockout that include the condition E _π?m _π (E _π is the energy of the knock-on pion) and the condition that the square Q ² of the virtual pion mass is large, the competing tree diagram is suppressed in relation to the pole diagram (this is not so in the case of pion photoproduction). From data of a p(e, e′π ⁺)n experiment involving longitudinal virtual photons γ _L ^* , the momentum distribution |Ψ _p ^nπ (k)|² of pions in the nucleon is extracted for the first time over the entire range of significant momenta k, and this result is used to determine the cutoff constant Λ_π and the value of S _p ^nπ ≈0.2. The momentum distribution of positive rho mesons in the soft section of the spectrum is determined from experimental data on the process p(e, e′π ⁺)n proceeding through the mechanism ρ ⁺+γ _T ^* → π ⁺ involving transverse photons. A way to determine the momentum distribution of omega mesons through data on the process p(e, e′π ⁰)p is indicated. Two forms of dynamics—instantaneous form and that of light-front dynamics (the latter does not involve the Z diagram)—are compared for the example where the calculations are performed for the spectroscopic factor S _N ^B? .     

Pionic contribution to the muon magnetic moment

A procedure is developed to derive an optimal lower bounds for the pionic contribution to the muon magnetic moment from analyticity of the pion form factor F(t), its normalization F(0)=1 and from experimental information from both the processes e^?p → e^?π⁺n and e⁺e^? → π⁺π^?. It represents essentially the solution of a certain kind of optimization problem in Hilbert space. Numerical results are presented and compared to the recent data for the muon magnetic moment; we find a_μ(π⁺π^?) ? 42 × 10^?9.     

Nuclear spectroscopy of90Y

The level structure of⁹⁰Y has been studied using the⁹¹Zr(t,α)⁹⁰Y and⁸⁹Y(n,γ)⁹⁰Y reactions. The proton pickup reaction was studied with 17 MeV tritons and a Q3D spectrometer. In the thermal⁸⁹Y(n, γ)⁹⁰Y reactionγ-rays from ≈100 to 6,857 keV were observed. In addition to previously known states and configurations, the ten states of theπ(p 3/2)^?1 v(d 5/2)¹ andπ(f 5/2)^?1 v(d 5/2)¹ configurations are assigned. Also many other new levels are identified from the (n, γ) data. The 0?state of theπ(f 5/2)^?1 v(d 5/2)¹ is assigned at 3,130keV. Finite-range shell model calculations suggest that the tensor force is necessary to reproduce the experimentally observed splittings.     

The low-lying states and configurations in138La

Tritons from the reaction¹³⁹La(d, t)¹³⁸La atE _d=16 MeV were analyzed at eleven reaction angles from 22 ° to 90 ° with a broad-range magnetic spectrograph. TheQ-value of the reaction is ?2522±5 keV. The nine lowest-lying states in¹³⁸La are interpreted in terms of the shell model configurations (πg _7/2)^?1 (vd _3/2)^?1, (πg _7/2)^?1 (vs _1/2)^?1 and (πg _7/2)^?2 (πd _5/2)^?1(vd _3/2)^?1. Seven levels in the energy range of 700–1300 keV are populated byl=5 transitions and are interpreted as coming from the (πg _7/2)^?1(vh _11/2)^?1 configuration. The ground state of¹³⁸La is shown to haveJ ^π=5⁺. Therefore, beta decay by unique second-forbidden transitions to the 2⁺ one-phonon states of¹³⁸Ce and¹³⁸Ba must be inferred in spite of unusually high logft values of 19.2 and 18.5, respectively.     

Quadrupole moment of the 19/2− isomer in115Sb

The quadrupole moment of the 19/2^? isomeric state in¹¹⁵Sb has been measured using the time differential perturbed angular distribution method. From the quadrupole coupling constante ² Qq/h=66(3) MHz atT=370 K in a Bi host the moment ratio is obtained relative to the stable ground state of¹²¹Sb as ¦Q(¹¹⁵Sb, 19/2^?)/Q(¹²¹Sb, 5/2⁺)¦ =1.45(7) resulting in a moment of ¦Q(¹¹⁵Sb, 19/2^?)¦=52(6) fm².     

The process e + e − → ωπ0 near the Φ resonance

The reaction e ⁺ e ^?→ωπ⁰ near a Φ resonance was studied with a spherical neutral detector at VEPP-2M e ⁺ e ^? collider. Both main modes of decay of a ω meson were investigated: ω→π⁺π^?π⁰ and ω→π ⁰γ. The probability of decay Φ→ωπ⁰ was obtained from the magnitude of the interference wave in the cross section for the reaction e ⁺ e ^?→ωπ⁰→ π⁺π^?π⁰π⁰: B(Φ→ωπ⁰) = (5.5 _?1.4 ^+1.6 ±0.3) ×10^?5. The ratio of the partial widths of the ω meson was obtained from the ratio of the cross sections for the two modes: Γ(ω→π⁰γ )/Γ(ω→π⁺π^?π⁰) = 0.0994 ± 0.0036 ± 0.0038.     

Energy spectra of cosmic pions and nucleons at the top of the atmosphere

The production spectra of cosmic pions and their primaries have been derived from the experimental muon spectrum by using the theories of Barrettet al. and Feynman. The calculated pion production spectrum takes the formI(E _π)d E _π = 0.206E _π ^{? 2.65} d E _πper cm² sec str GeV in the energy range 3<E _π<1500 GeV and the nucleon spectrum follows the relationN(E _p)d E _p = 2.7 × 10⁴ (E _p/GeV)^2.65 d E _pper m² sec str GeV in the range 5 <E _p <3000 Gev.     

The e + e −→π0π0γ process below 1.0 GeV

The e ⁺ e ^?→π⁰π⁰ γreaction was studied in the energy range 0.36–0.97 GeV on a VEPP-2M e ⁺ e ^? collider with an SND detector. The decay probabilities were found to be B(ω→ π⁰π⁰γ)= (7.8 ±2.7±2.0)×10^?5 and B(π→ π⁰π⁰γ)= (4.8 _?1.8 ^+3.4 ±0.2)×10^?5.     

Study of process e + e − → π+π−π0π0 at energies √s < 1 GeV with the spherical neutral detector

The cross section for the process e ⁺ e ^? → π⁺π^?π⁰π⁰ has been measured in an experiment with a spherical neutral detector, with the cross section at energies √s < 920 MeV having been measured for the first time. The model of vector dominance describes well the data obtained if the ρ, ρ′, and ρ″ resonances are taken into account. The probability of the decay ρ → π⁺π^?π⁰π⁰ is B(ρ → π⁺π^?π⁰π⁰) = (1.60 ± 0.74 ± 0.18) × 10^?5. The upper limit for the decay ω → π⁺π^?π⁰π⁰ has been improved by two orders of magnitude compared to previous measurements and is B(ω → π⁺π^?π⁰π⁰) < 2 × 10^?4 at a 90% confidence level.     

Diffraction dissociation of neutrons in the reaction dp → pppπ− at 25 GeV/c

We observe the reaction dp → p_spec (pπ^?)p in a bubble chamber exposure at 25 GeV/c incident deuteron momentum. The (pπ^?) system with invariant mass below 2.0 GeV is interpreted as neutron diffraction dissociation. The (pπ^?) mass spectra show little if any direct evidence of N¹ production. The decay angular distributions and the momentum transfer distributions of the (pπ^?) system suggest a smooth increase in contributions from higher partial waves $\text{(J ?}\text{3}\text{2}\text{)}$ with increased mass or momentum transfer. A simple partial-wave analysis shows a P₁₁ contribution below 1.3 GeV for small ?t′ and a dominant D₁₃ contribution elsewhere. Both the P₁₁ and D₁₃ amplitudes peak far below the N¹(1470) and N¹(1520) resonances. We also find evidence for the charge-exchange reaction np → p(pπ^?). In this process the (pπ^?) system shows evidence for Δ^o(1236) and N¹(1520) production.     

Study of the centrally produced ωρ0 and ωω systems inpp interactions at 300 GeV/c

We have performed a search for vector-vector final states centrally produced in proton proton interactions at 300 GeV/c using the CERN Ω spectrometer. Evidence is found for ωρ⁰ production in the reactionpp→p _f (2π⁺2π^?2π⁰)p _s and for ωω production in the reactionpp→p _f (2π⁺2π^?2π⁰)p _s . However no evidence is found for ωø production in the reactionpp→p _f (K ⁺ K ^?π⁺π^?π⁰)p _s .     

The energy dependence of single particle spectra in e+e− annihilation

We present explicit predictions of the statistical bootstrap model for inclusive single particle spectra in e⁺e^? annihilation. The distribution (ω/σ_tot·E) (dσ/p² dp) is found to become, for E ? 3 GeV, a function only of the secondary energy ω, independent of the incident e⁺d^? energy E.     

Eine PrÄzisionsmessung des VerhÄltnisses der Spinresonanzfrequenz von Protonen zur Zyklotronfrequenz freier Elektronen im gleichen Magnetfeld

A new precision measurement of the ratio of the proton NMR frequency to the cyclotron frequency of free electrons in the same magnetic field, Ω _p /Ω_e=γ _p mc/e, has been performed. A cyclotron resonance linewidth of 5 ppm only and a reduction of the large space charge shifts, amounting up to the order of 50 ppm in earlier published measurements, enabled a high accuracy. The final result is Ω _p /Ω _e =1.5209945×10^?3±0.5 ppm, where the NMR is referred to a long cylindrical sample of H₂O, 0.2 m CuSO₄. Corrected to the free proton, we get Ω _p /Ω _e =1.5210329×10^?3±0.6 ppm. Combination of our result with an EPR-measurement ofLambe yields a free electrong-factor ofg=2(1+(α/2π)?(0.30±0.09) (α/π)²) in good agreement with the theoretical valueg=2(1+(α/2π)?0.328(α/π)²±...).     

Optimal bounds for the pion form factor from analyticity and experimental data

Optimal bounds for the pion electromagnetic form factor F(t) below threshold and on the pion mean-square charge radius 〈r_π²〉 = 6F'(0) are derived. Use is made of analyticity arguments and of experimental data on F(t) from e⁺e^? → π⁺π^? as well as e^?p → e^?nπ⁺. The method accounts in an approximate way for the statistical errors of the experimental information. Numerical results for F(t) are calculated for the CEA as well as the DESY electroproduction data.     

Study of the (p,pn) reaction in light nuclei

The (p, pn) reaction on ²H, ⁶Li, ⁷Li, ⁹Be has been studied at 47 MeV bombarding energy. Excitation energy spectra and energy sharing spectra are presented. Fragmentary information on ¹⁰B, ¹¹B and ¹²C was also obtained. Sequential decay contributions to the ⁶Li(p, pn)⁵Li¹ reaction suggest an admixture of parentage $\text{(α)π(}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)π(}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ for the (3^?), 23 MeV excited state of ⁶Be. A possible 15.5 MeV excited state in ⁶Be is reported. An extensive study of the ⁹Be (p, pn)⁸Be reaction for 45 MeV protons was made. Results for θ_p = θ_n = 25°, 30°, 35°, 40°, 45°, 55°, 65°; θ_n = 40°, θ_p = 25°, 30°, 35°, 40°, 45°, 55°, 65°; θ_p/θ_n = 40°/45°, 38.5° are reported and compared to DWIA calculations. Agreement is good when the lower momentum components of the wave function are sampled, and deteriorates as higher momenta are required. Results are in agreement with the Cohen and Kurath spectroscopic factors for ⁹Be.     

B → πlΝ form factors calculated on the light-front

A consistent treatment of B → πlν decay is given on the light-front. The B to π transition form factors are calculated in the entire physical range of momentum transfer for the first time. The valence-quark contribution is obtained using relativistic light-front wave functions. Higher quark-antiquark Fock-state of the B-meson bound state is represented effectively by the ¦B*π〉 configuration, and its effect is calculated in the chiral perturbation theory. Wave function renormalization is taken into account consistently. The ¦B*π〉 contribution dominates near the zero-recoil point (q ² ? 25 GeV²), and decreases rapidly as the recoil momentum increases. The calculated form factor ?+(q ²) follows approximately a dipole q ²-dependence in the entire range of momentum transfer. We estimate that ¦V _ub¦=0.003.     

π−Electroproduction off deuterium above the resonance region

The reactionse + d → e' + p_S + p + π^?ande + d → e' + n_S + n + π⁺ were measured detecting electron and pion in coincidence at an invariant hadronic mass of 2.19 GeV. The measurements were performed at electron four-momentum transfer squared of f² = 0.70 and 1.35 GeV² in the range of t = (γ_v?π)² between t_minand ?1.0 GeV². The cross section d²σ/dtdφ of the reaction e + n → e' + p + π^? was determined.