Spin-dependent part of ppˉp\bar{p} interaction cross section and Nijmegen potential

Low energy $p\bar{p}$ interaction is considered taking into account the polarization of both particles. The corresponding cross sections are calculated using the Nijmegen nucleon-antinucleon optical potential. Then they are applied to the analysis of the polarization buildup which is due to the interaction of stored antiprotons with polarized protons of a hydrogen target. It is shown that, at realistic parameters of a storage ring and a target, the filtering mechanism may provide a noticeable polarization in a time comparable with the beam lifetime.Comment: 10 pages, 3 figure

Spin effects in ppˉp\bar p interaction and their possible use to polarize antiproton beams

Low energy $p\bar p$ interaction is considered taking into account the polarization of both particles. The corresponding cross sections are calculated using the Paris nucleon-antinucleon optical potential. Then they are applied to the analysis of the polarization buildup which is due to the interaction of stored antiprotons with polarized protons of a hydrogen target. It is shown that, at realistic parameters of a storage ring and a target, the filtering mechanism provides a noticeable polarization in a time comparable with the beam lifetime.Comment: 10 pages, 4 figure

The Nuclear Response in Delta-Isobar Region in the (3 ⁣^3\!He,t) Reaction

The excitation of a $\Delta$-isobar in a finite nucleus in charge--exchange ($^3\!$He,t) reaction is discussed in terms of a nuclear response function. The medium effects modifying a $\Delta$- and a pion propagation were considered for a finite size nucleus. The Glauber approach has been used for distortion of a $^3\!$He and a triton in the initial and the final states. The effects determining the peak positions and its width are discussed. Large displacement width for the $\Delta$ - h excitations and considerable contribution of coherent pion production were found for the reaction on $^{12}$C.Comment: 29 pages including 8 figures, IU/NTC 92-3

Nuclear Anapole Moments in Single Particle Approximation

Nuclear anapole moments of \;^{133}Cs, \;^{203,205}Tl, \;^{207}Pb, \;^{209}Bi are treated in the single-particle approximation. Analytical results are obtained for the oscillator potential without spin-orbit interaction. Then the anapole moments are calculated numerically in a Woods-Saxon potential which includes spin-orbit interaction. The results obtained demonstrate a remarkable stability of nuclear anapole moment calculations in the single-particle approximation.Comment: 20 pages, LateX, One figure available upon request, BINP-93-11

Virtual Pion Scattering

We propose a theory which exploits the charge-exchange reactions ($^3$He,$^3$H$\pi^+$) and (p,n$\pi^+$) as effective sources of virtual pions. We consider processes in which the creation of virtual pions is followed by conventional coupled-channel pion scattering to discrete nuclear states. This picture allows us to incorporate successful theories of pion scattering and utilize virtual pions as probes of the nuclear matter. For coherent pion production we clearly demonstrate that the shift of the coherent peak position in the excitation function of $^3$He-A relative to $^3$He-N scattering is determined entirely by the pion nucleus rescattering.Comment: 10 pages, revtex 3, 2 figures attached in file figures.u

The anapole moment and nucleon weak interactions

From the recent measurement of parity nonconservation (PNC) in the Cs atom we have extracted the constant of the nuclear spin dependent electron-nucleon PNC interaction, $\kappa = 0.442 (63)$; the anapole moment constant, $\kappa_a = 0.364 (62)$; the strength of the PNC proton-nucleus potential, $g_p = 7.3 \pm 1.2 (exp.) \pm 1.5 (theor.)$; the $\pi$-meson-nucleon interaction constant, $f_\pi \equiv h_\pi^{1} = [9.5 \pm 2.1 (exp.) \pm 3.5 (theor.)] \times 10^{-7}$; and the strength of the neutron-nucleus potential, $g_n = -1.7 \pm 0.8 (exp.) \pm 1.3 (theor.)$.Comment: Uses RevTex, 12 pages. We have added an explanation of the effect of finite nuclear siz

Effect of quark-mass variation on big bang nucleosynthesis

We calculate the effect of variation in the light-current quark mass, $m_q$, on standard big bang nucleosynthesis. A change in $m_q$ at during the era of nucleosynthesis affects nuclear reaction rates, and hence primordial abundances, via changes the binding energies of light nuclei. It is found that a relative variation of $\delta m_q/m_q = 0.016 \pm 0.005$ provides better agreement between observed primordial abundances and those predicted by theory. This is largely due to resolution of the existing discrepancies for 7Li. However this method ignores possible changes in the position of resonances in nuclear reactions. The predicted 7Li abundance has a strong dependence on the cross-section of the resonant reactions 3He(d,p)4He and t(d,n)4He. We show that changes in $m_q$ at the time of BBN could shift the position of these resonances away from the Gamow window and lead to an increased production of 7Li, exacerbating the lithium problem

Nuclear magnetization distribution and hyperfine splitting in Bi82+^{82+} ion

Hyperfine splitting in Bi$^{82+}$ and Pb$^{81+}$ ions was calculated using continuum RPA approach with effective residual forces. To fix the parameters of the theory the nuclear magnetic dipole moments of two one- particle and two one-hole nuclei around $^{208}$Pb were calculated using the same approach. The contribution from velocity dependent two-body spin- orbit residual interaction was calculated explicitly. Additionally, the octupole moment of $^{209}$Bi and the hfs in muonic bismuth atom were calculated as well in the same approach. All the calculated observables, except the electronic hfs in $^{209}$Bi, are in good agreement with the data. We argue for more accurate measurement of the octupole moment and the muonic hfs for $^{209}$Bi.Comment: 11 pages, 5 figure

Conductivity of 2D many-component electron gas, partially-quantized by magnetic field

The 2D semimetal consisting of heavy holes and light electrons is studied. The consideration is based on assumption that electrons are quantized by magnetic field while holes remain classical. We assume also that the interaction between components is weak and the conversion between components is absent. The kinetic equation for holes colliding with quantized electrons is utilized. It has been stated that the inter-component friction and corresponding correction to the dissipative conductivity $\sigma_{xx}$ {\it do not vanish at zero temperature} due to degeneracy of the Landau levels. This correction arises when the Fermi level crosses the Landau level. The limits of kinetic equation applicability were found. We also study the situation of kinetic memory when particles repeatedly return to the points of their meeting.Comment: 13 pages, 1 figur

Экспериментальное исследование энергетической и экологической эффективности использования теплоты фазовых переходов поровой влаги древесины в теплонасосных сушильных камерах

The article deals with one of the most energetically and ecologically effective technologies of wood drying. Special construction polystyrene wall blocks are used as frame fillings of experimental the drying chamber according to the technology “Plastbau”, known with its ability to improved heat-insulating properties. The results of the experimental study of the thermal regime show the high energy and ecological efficiency of this wood drying technology.В статье рассматривается одна из наиболее энергетически и экологически эффективных технологий сушки древесины, базирующихся на применении тепловых насосов. Приведенные результаты экспериментальных исследований теплового режима подтверждают высокую энергетическую и экологическую эффективность рассматриваемой технологии сушки древесины