pp interactions in P-wave and related topics

The nucleon-antinucleon (NN) annihilation process provides a fertile testing ground for microscopic hadron exchange and/or quark models. TheNN system offers a rich ensemble of annihilation channels, whose relative BRs provide strong constraints on dynamical models. Recent experiments show that values of BRs display a significant dependence onL, S andI. These dynamical selection rules,i.e. the suppression of transitions alloweda priori by conservation of quantum numbers, provide key signatures of the annihilation mechanism, and suggest dynamical content beyond simple statistical or flavour symmetry models.     

Measurement of tensor analyzing powers in deuteron photodisintegration

A new accurate measurement of the tensor analyzing powers T20, T21, and T22 in deuteron photodisintegration has been performed. Wide-aperture nonmagnetic detectors allowed broad kinematic coverage in a single set up: E(gamma)=25 to 600 MeV, and theta(p)(cm)=24 degrees to 48 degrees and 70 degrees to 102 degrees . The new data provide a significant improvement over the few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.     

Local realistic NN interactions in the four-nucleon problem

The ⁴He problem with realistic NN interactions is solved and systematically studied. All such interactions are found to underbind ⁴He significantly. Possible sources of this underbinding are discussed. The method of hyperspherical harmonics is used.     

Precise measurement of deuteron tensor analyzing powers with BLAST

We report a precision measurement of the deuteron tensor analyzing powers T(20) and T(21) at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range Q=2.15-4.50 fm(-1) with the Bates Large Acceptance Spectrometer Toroid using a highly polarized deuterium internal gas target. The data are in excellent agreement with calculations in a framework of effective field theory. The deuteron charge monopole and quadrupole form factors G(C) and G(Q) were separated with improved precision, and the location of the first node of G(C) was confirmed at Q=4.19±0.05 fm(-1). The new data provide a strong constraint on theoretical models in a momentum transfer range covering the minimum of T(20) and the first node of G(C).     

Modeling and analyzing of botnet interactions

The dynamics of interacting botnets and the effects of the strategies selected by interacting botnet owners on the spread of botnets remain unclear. As a result, in this paper, we present a botnet interaction model, obtained by coupling a fast evolutionary game dynamics to a slow population dynamics model, in which two botnet types are considered. We analyze the fast evolutionary game model and obtain two stable equilibria. Additionally, we substitute them into the complete model and get two reduced models. Such models allow us to study the effects of strategies selected by botnet owners. Analysis of the models shows that when all owners adopt the cooperative strategy both types of botnets can survive with much lower contact rates. However, while they choose the competitive strategy one type of botnet will become extinct and the other will persist with a lower infection rate. The equilibrium conditions of the evolutionary game model, which can guide us in designing effective counter-botnet methods, are also obtained.     

NN̄ bound states and resonances near threshold from ππ, πN,NN interactions

The long and medium range NN? potential is deduced by G parity transformation from a new NN theoretical potential which was in turn derived from πN and ππ interactions. Assuming very simple forms for the short range part, we examine the ability of this potential to explain the NN? bound states and resonance at energies near threshold.     

The vanishing analyzing powers in electron-proton elastic scattering; symmetries and dynamics

In high energy electron-proton elastic scattering the two parity-conserving analyzing powers vanish in the one-photon-exchange approximation. The electron analyzing-power vanishes from electron helicity-conservation, but the underlying reason (s) for the vanishing of the proton analyzing-power is (are) not clear. Therefore, a more detailed examination of this question has been made and is reported here. It is then noted that the proton analyzing-power is an optimum experimental observable for the determination of higher order contributions to this basic electron-nucleon electromagnetic interaction.     

Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering

High-precision vector and tensor analyzing powers of elastic deuteron-proton ( d + p) scattering have been measured at intermediate energies to investigate effects of three-nucleon forces. Angular distributions in the range of 70^°-120^° in the center-of mass frame for incident-deuteron energies E _d ^lab = 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring the ^12C (d, α)^10B(2⁺) reaction at 0^°. Results of the measurements are compared with state-of-the-art three-nucleon calculations. The present modeling of nucleon-nucleon forces and its extension to the three-nucleon system is not sufficient to describe the high-precision data consistently and requires, therefore, further investigation.     

The three-nucleon system near the N-d threshold

The three-nucleon system is studied at energies a few hundred keV above the N-d threshold. Measurements of the tensor analyzing powers T₂₀ and T₂₁ for p-d elastic scattering at E_c.m. = 432 keV are presented together with the corresponding theoretical predictions. The calculations are extended to very low energies since they are useful for extracting the p-d scattering lengths from the experimental data. The interaction considered here is the Argonne V18 potential plus the Urbana three-nucleon potential. The calculation of the asymptotic D- to S-state ratio for ³H and ³He, for which recent experimental results are available, is also presented.     

Measurement of the tensor analyzing powers T20 and T21 in elastic electron-deuteron scattering

The tensor analyzing power components T20 and T21 have been measured in elastic electron-deuteron scattering at the 2 GeV electron storage ring VEPP-3, Novosibirsk, in a four-momentum transfer range from 8.4 to 21.6 fm(-2). A new polarized internal gas target with an intense cryogenic atomic beam source was used. The new data determine the deuteron form factors G(C) and G(Q) in an important range of momentum transfer where the first node of the deuteron monopole charge form factor is located. The new results are compared with previous data and with some theoretical predictions.     

Effective theory of NN interactions in a separable representation

We consider the effective field theory of the NN system in a separable representation. The pionic part of the effective potential is included nonperturbatively and approximated by a separable potential. The use of a separable representation allows for the explicit solution of the Lippmann-Schwinger equation and a consistent renormalization procedure. The phase shifts in the ¹ S ₀ channel are calculated to subleading order.     

Differential cross sections and analyzing powers for pd elastic scattering below 1.0 MeV

Differential cross sections for the elastic pd scattering were measured at seven energies between 0.4 and 1.0 MeV for scattering angles from θ_c.m. = 44.5° to 149.2°. A mixture of D₂ and Kr was used as target gas and the pd differential cross sections were determined relative to those of pKr scattering with a statistical error of $\text{Δσ}\text{σ}$ ～5 × 10^?3. Analyzing powers for $\text{p}$d scattering were measured at 0.8, 0.9 and 1.0 MeV with a statistical error of ΔA_y ～5 × 10^?4.     

N-d backward scattering and virtual states of the trinucleon

The 180° nucleon-deutron elastic cross section exhibits a peak as a function of nucleon energy which has been interpreted as due to a virtual state of the trinucleon. This interpretation is examined within the context of the Amado model.     

Vector and tensor analyzing powers in deuteron-proton elastic scattering atE d=70 MeV

Angular distributions of analyzing powersA _yandA _yyhave been measured ind-p elastic scattering at 70 MeV. The data are compared with Faddeev calcuiations using various tensor nucleon-nucleon interactions.     

Applying scattered-ion spectroscopy to the analyzing of plasma-surface interactions

A setup based on an ion mass monochromator and intended for investigating plasma interactions with surfaces of plasma facility materials is described. It analyzes the composition and thickness of surface films by means of ion scattering spectroscopy. An analysis of the composition of stainless steel and graphite is performed using helium and argon ions in the range of 2?C8 keV. The obtained results demonstrate the possibility of investigating the dynamics of carbon and oxygen behavior on the surface of materials using negatively charged recoil ions and scattered helium ions.     

Energy dependence of tensor analyzing powers in deuteron elastic scattering from 208Pb

Differential cross section and all four analyzing powers iT₁₁, T₂₀, T₃₁ and T₂₂ have been measured for deuteron elastic scattering from ²⁰⁸Pb at incident energies from 10 to 23 MeV. The energy dependence of the tensor analyzing powers was investigated. A considerable deviation of the data from optical-model calculations including a T_r-type tensor potential is found near the Coulomb barrier.