The pion and kaon spectra in the atmosphere are derived from primary nucleon spectrum determined by GRIGOROV et al.; they satisfy the relations N(Eπ) dEπ = 0.187 EdEπ and N(Ek) dEk = 0.017 EdEk, respectively. By using the pion-kaon atmospheric diffusion equation the sea level muon spectrum is calculated and the result compared with the magnetic spectrograph data of ALLKOFER et al. and AYRE et al. 相似文献
The spectra of cosmic pions and nucleons at an atmospheric depth of 100 g cm?2 have been derived from sea level muon spectra at low and high latitudes. The derived spectra of pions and nucleons at low and high latitudes follow the relations N(Eπ) dEπ = 0.23 Eπ?2.68dEπ and N(Ep) dEp = 2.98 EdEp per cm2 sec str GeV in the energy range 15–1200 GeV. Below 15 GeV it is found that the exponent of the energy spectrum is very much dependent upon the incident energy and latitude of the location. The major difference between low and high latitude pion spectra can be explained in terms of geomagnetic effects. 相似文献
Quantitative optical spectroscopy measurements of the emission spectra of the N(B2∑u,)ν′→X2∑gν″ transition (first negative system) in an Ar-N2 microwave discharge at atmospheric pressure have allowed determination of the rate coefficient of the production of N molecules in the B2 ∑u, state with vibrational level ν′ = 0. The N(B2∑u, ν′) molecules are produced by the reaction in a surface-wave-induced microwave discharge (2450 MHz) sustained in an open-ended dielectric tube. The rate coefficient K (T) has been obtained for ν′ν″ = 0 for different gas temperatures by varying the incident microwave power. The K00(T) values are between 7.10?10 and 4.10?10 cm3 s?1 for the temperature range 2500 to 3450K. 相似文献
The matrix elements for the hyperfine structure of the configuration lll in SL-Kopplung are expressed as linear combinations of the electron coupling constants αli(10), αli(01), αli(12). 相似文献
For an arbitrary given distribution of dislocations and disclinations the general state of stress of a mechanical continuum is investigated. The medium is reacting with stresses and momentum stresses (Cosserat continuum). By means of differential geometry it is shown that the deformations ik and ?ik of two arbitrary materials with identical distributions of defects differ merely by a displacement field ui(xr, t). If ik are the eigendeformations of an isotropic medium, then in the linear theory the field ui of a Cosserat continuum can be separated from ik. If the problem is static the ui obey the potential equation of Bopp-Podolsky electrodynamics. As source only torsion (dislocations and torsion of disclinations) is acting. To give an example the field ui for straight dislocations and disclinations is calculated. Especially the problem of singularities is discussed. 相似文献
Some structural considerations are made on the Finslerian gravitational field: A Finslerian metrical structure such as gλχ(x, y) = γλχ(x) + hλχ(x, y) is proposed, where γλχ denotes the Riemann metric of Einstein's gravitational field, while hλχ the Finsler metric induced by the Riemann metric hij(y) of the internal field; The intrinsic behaviour of the internal variable y, which is expressed as ?i = K(x, y) yj in the internal field, is grasped by the Finslerian parallelism δyi (=0), which is reflected in the spatial structure of the external gravitational field by the mapping relation δyχ = e(x) δyi. The whole metrical Finsler connection D for gλχ(i.e., Dgλχ = 0) is determined by taking account of the intrinsic behaviour δyχ. 相似文献
We study the Schwinger mechanism for gluon-pair production in the presence of an arbitrary time-dependent chromo-electric
background field Ea(t) with arbitrary color index a=1,2,…,8 in SU(3) by directly evaluating the path integral. We obtain an exact expression for the probability of non-perturbative
gluon-pair production per unit time per unit volume and per unit transverse momentum,
, from arbitrary Ea(t). We show that the tadpole (or single-gluon) effective action does not contribute to the non-perturbative gluon-pair production
rate,
. We find that the exact result for non-perturbative gluon-pair production is independent of all the time derivatives
, where n=1,2,…,∞, and that it has the same functional dependence on the two Casimir invariants, [Ea(t)Ea(t)] and [dabcEa(t)Eb(t)Ec(t)]2, as the constant chromo-electric field Ea result with the replacement: Ea→Ea(t). This result relies crucially on the validity of the shift conjecture, which has not yet been established. This result may
be relevant to the study of the production of a non-perturbative quark–gluon plasma at RHIC and LHC. 相似文献
This work is devoted to the determination of the vibrational population of hydrogen molecules in the ground and excited electronic states from the analysis of visible spectra of the H2 molecules excited by an RF discharge in an expanding thermal arc plasma. Comparison of the experimental results on relative electron-impact excitation cross sections for the transition H2(X1Σ, υ0 = 0)→ H2(d3IIu, υ′) with other experiments, and with calculations based on the Franck-Condon principle, shows good agreement. This means, that for plasma under investigation: 1) in the ground electronic state H2(d3IIu,υ′), only the lowest vibrational level with υ0 = 0 is significantly populated, and 2) direct electron exictation of H2(d3IIu, υ′, υ′) state from the ground state H2(X1Σ, υ0 = 0) dominates. 相似文献
The minimal Standard Model exhibits a nontrivial chiral U(2) symmetry if the VEV and the hypercharge splitting Δ = (y-y)/2 of right-handed leptons (quarks) in a family vanish and Q = T0 + Y independently in each helicity sector. As a generalization, we start with SU(2)L × SU(2)R × U(1)(B-L) and introduce Δ as a continuous parameter which is a measure of explicit symmetry breakdown. Values 0 ? Δ ? 1/2 take the neutral generator of the isospin ½ representation to the singlet representation, i.e. ‘deformes’ the LR representation into the minimal Standard one. The corresponding classical O(3)-breaking term is a magnetic field perpendicular to the x3-axis. A simple mapping on the fundamental Drinfeld-Jimbo q-deformed SU(2) representation is given. 相似文献
Plasma presheath and saturation current collection by a planar Langmuir probe in a strong magnetic field perpendicular to the probe surface ares described with the diffusion model. The model takes into consideration the geometry of the probe, that is its size and shape, and dependence of the cross-field charged particles' transport into the effective collection region of the probe on the parallel-field transport to the probe. Experimental study of planar Langmiur probe I—V characteristics in D.C. discharge argon plasma in strong magnetic fields confirms the possibility of deriving the cross-field diffusion coefficient, D, from the measured electron satuation current. Additional dependence of the electron saturation current on the parallel-field diffusion coefficient, D, and the ion temperature, Ti, derived in the approximate Stangeby's study using the diffusion model of current collection by a planar surface (Stangeby, P. C., J. Phys. D: Appl. Phys. 15 (1982) 1007) can be eliminated with more rigorous calculation. Series of measurements on two neutral pressures and various magnetic fields gave reproducible values of D, approximately given by relation D ≈ (δn/〈n〉) kBTe/(eB). 相似文献