共查询到20条相似文献,搜索用时 171 毫秒
1.
Shinsho Oryu 《Few-Body Systems》2013,54(1-4):283-286
The Fourier transform of the Born term of the AGS equation in the NNπ-system generates an energy-dependent Yukawa-type local NN-quasi-potential. An appropriate average with respect to energy suggests a variety of local NN-potentials with different ranges: 1/r(r + a) m?1 (for 2 ≤ m) where in the long range region it becomes 1/r m , while in the short range region the Yukawa-type potential e ?(m?1)r/a /r results. Therefore, one finds that the Yukawa potential is automatically accompanied by an additional longer range interaction 1/r m . For m = 2, the potential 1/r 2 produces Efimov-like bound states in the deuteron spectra. The m = 6, 7 cases lead to the Van der Waals potential. 相似文献
2.
A simple expression for the electron density of then-shell of the Coulomb atom with the nuclear charge Zρ n(r)=Z 3 π ?2 n ?3(2Z ?1 r ?1?n ?2)1/2 is found in the semi-classical approximation. It is used for the asymptotic estimation of averages 〈r a 〉 (?2<a<∞). An explicit dependence of the leading oscillatory contribution to 〈r a 〉 due to angular moments on the electron number is also obtained. 相似文献
3.
A.T. Filippov 《Physics letters. [Part B]》1974,51(4):379-382
The pion is treated as a fermion-antifermion composite state, described by the Euclidean Bethe-Salpeter equation. The kernel of the equation is a local potential having an exponentially infinite spectral function, connected with the empirical mass spectrum of resonances. For the simplest potential U(r) = f2(r2?a2)?1 the equation for the massless pion is solved by using WKBJ method, and the parameters f, a and the fermion mass M are estimated. 相似文献
4.
We have searched for the exotic annihilation of orthopositronium, o-Ps → a0 + γ, where a0 denotes a neutral particle of mass ma < 2me. For the ratio of this decay mode to the 3γ decay mode, upper limits have been derived in the range 5 × 10?6?1 × 10?6 (for ma varying from 100 to 900 keV). This result excludes the hypothesis that this exotic decay is responsible for the discrepancy between the theoretical and experimental values of the orthopositronium lifetime. 相似文献
5.
E. G. Drukarev M. Ya. Amusia E. Z. Liverts R. Krivec V. B. Mandelzweig 《Journal of Experimental and Theoretical Physics》2006,103(5):690-696
We find an approximate analytic form for the solution ψ(r 1, r 2, r 12) of the Schrödinger equation for a system of two electrons bound to a nucleus in the spatial regions r 1 = r 2 = 0 and r 12 = 0, which are of great importance for a number of physical processes. The forms are based on the well-known behavior of ψ(r 1, r 2, r 12) near the singular triple coalescence point. The approximate functions are compared to the locally exact ones obtained earlier by the correlation function hyperspherical harmonic (CFHH) method for the helium atom, light helium-like ions, and the negative ion of hydrogen H?. The functions are shown to determine a natural basis for the expansion of CFHH functions in the considered spatial region. We demonstrate how these approximate functions simplify calculations of high-energy ionization processes. 相似文献
6.
Fitted phase-shift curves from the threshold to the dipion mass, which is equal to 1 GeV, are constructed on the basis of all available experimental values of the S-and P-wave phase shifts for five charged channels of pion-pion scattering. The resulting phase-shift curves are introduced in the Roy equations in order to obtain the subtraction constants λ l I (s). By using these subtraction-constant values as functions of the dipion mass, the S 0-and S 2-wave pion-pion scattering lengths are found to be a 0 0 = (0.240 ± 0.023)m π ?1 and a 0 2 = (?0.034 ± 0.013)m π ?1 . A strong correlation of the S-wave scattering lengths is demonstrated. 相似文献
7.
Theoretical energies of adsorption have been calculated for the adsorption of Ar and Kr on the (100) faces of sodium and potassium bromides, in each case using three different potential functions. The best agreement between theoretical and experimental values was obtained using the Lennard Jones 6–12 function, U= ?Cr?6 + Br?12 and the 6m-expm function, .The 6km-exp function, U = ?Cr?6 + B exp (-br), where C is obtained using the Kirkwood Müller approximation, gave very poor agreement. In all cases the energetically favoured site was shown to be above the mid-point of a lattice square (composed of two anions and cations). 相似文献
8.
A. Gold 《Zeitschrift für Physik B Condensed Matter》1996,101(1):121-130
We calculate the local-field corrections G(q, q z) for charged bosons at zero temperature in a superlattice with interlayer distance d. An analytical expression for the local-field correction is described. The sum-rule version of the self-consistent approach for the local-field correction is used to discuss the effects of correlation. The RPAparameter r s and the ratio d/a* determine correlation effects. a* is the effective Bohr radius. The stability region for the Bose condensate r s < r sc as a function of d/a* is determined: r sc ≈ (d/a*)3/4. The ground-state energy of the layered Bose condensate is calculated and optical and acoustical plasmons are discussed. We predict a roton structure for optical plasmons for r s > r sr with r sr ≈ 0.5 (d/a*)3/4. 相似文献
9.
We attempt to impose elastic unitarity on the forward π-π scattering using the Veneziano Amplitude together with a crossing symmetric subtraction term as an input. TheN/D method is used and thep, ? mesons are interpreted as CDD poles. The self consistency requirement led to the evalutation of the low energy parameters and theS andP-wave phase shifts. The values of the scattering lengths obtained area 0 0 =0.084m π ?1 ,a 2 0 =?0.024m π ?1 ,a 1 1 =0.047m π ?3 . 相似文献
10.
Six red degraded bands in the region 5300–5700 Å have been observed and attributed to the radical AsSe. Arguments are presented to suggest that the bands arise from two subsystems of a2Πr(a)-X2Πr(a) transition and that the value of is approximately 281 cm?1. 相似文献
11.
《Physica A》1988,150(2):339-356
We extend the generalized Smoluchowski equation to descrbe the diffusional relaxation of position and orientation in a suspension of interacting spherical colloid particles. Considering a tracer particle which interacts with other particles through spherically symmetric pair potentials and with an external field we obtain a cluster expansion representation of the orientational time correlation functions for the tracer. The one and two body cluster contributions are studied explicitly at short times. Working to first order in volume fraction φ we show that the initial slope of the time correlation functions is described by a modified diffusion coefficient Dr = Dr0(1 −Crφ) where Cr is a number determined by hydrodynamic and potential interactions. We evaluate Cr numerically for spheres with slip-stick hydrodynamic boundary conditions and also for permeable spheres. 相似文献
12.
13.
Sameer M. Ikhdair 《Few-Body Systems》2013,54(11):1987-1995
The generalized form of Killingbeck potential is an attractive Coulomb term plus a linear term and a harmonic oscillator term, i.e. ?a/r + br + λr 2, which has a useful application in quarkonium spectroscopy. The ground state energy with the corresponding wave function are obtained for any arbitrary m-state in two-dimensional Klein–Gordon equation with equal mixture of scalar–vector Killingbeck potentials in the presence of constant magnetic and singular Ahoronov–Bohm flux fields perpendicular to the plane where the interacting charged particle is confined. The analytical exact iteration method is used in our solution. We obtain the energy eigensolutions for particle and antiparticle corresponding to S(r) = V(r) and S(r) = ?V(r) cases, respectively. Some special cases like the Coulomb, harmonic oscillator potentials and the nonrelativistic limits are found in presence and absence of external fields. 相似文献
14.
M. Noga 《Physics letters. [Part B]》1975,59(5):466-470
The following theorem is proven: Every lepton with the mass m, electric charge q and spin J belonging to any representation of a non-abelian gauge group must have the magnetic moment μ = qJm?1, electric mean squared radius r2 = qJ(J + 1)m?2 and electric quadrupole moment Q = qJ(2J ? 1)m?2 in the first order of the electromagnetic effects in an arbitrary renormalizable theory with the non-abelian gauge group symmetry which permits the validity of the Gerasimow-Drell-Hearn and Cabibbo-Radicati sum rules. The formula for the magnetic moment applies also for an abelian symmetry and remains valid even if the gauge symmetry is spontaneously broken. 相似文献
15.
H. Faissner W. Heinrigs A. Preussger J. Reitz D. Samm H. Tuchscherer P. Kostka K. Lanius S. Nowak C. Spiering M. Walter A. Badertscher M. Daum R. Dietlicher A. Zehnder 《Zeitschrift fur Physik C Particles and Fields》1989,44(4):557-566
A search was made for the decay of a light neutral particle into ane + e ?-pair behind the dump of the PSI (formerly SIN) 590 MeV proton beam. The detector consisted of two counter triggered optical spark chambers mounted two meters apart. A decay signal would have been detected within a cone of about 10° around the direction to the beam dump. For 300 coulomb of protons we found no excess of decay events over the backgroud. Consequently we can exclude the existence of a standard axion forX-parameters between 13.6 and 300, equivalent to masses between 2m e and 20 MeV. For the decay modea 0→e + e ? the standard axion model predicts a decay rate Г ee ≈2×106 m a ?1 MeVs?1 whereas our analysis yields a limit Г ee <36m a ?1 MeVs?1 with 90% confidence. In the general case, e.g. for an axionlike boson χ0 we exclude values for the decay constantf x <104 GeV with 90% confidence for masses between 2m e and 20 MeV. 相似文献
16.
We determine the r1 (p) coefficients of the argon I 4p 1P1 state (2p2 with Paschen notation) with the λ = 696.5 nm line and of the argon II 4p 2D state with the λ = 488.0 nm line in a highly ionized, low temperature (Te = 3?4 eV), magnetically confined (0.2 T) plasma of a hollow cathode arc with electron densities ne between 1019 and 1020 m?3. The neutral density n0 is 1019 m?3 or less. The r1 (4p) values are (6 ± 2) × 10?5 for argon I and (5 ± 2) × 10?4 for argon II. 相似文献
17.
T.C. Lubensky 《Journal of Physics and Chemistry of Solids》1973,34(3):365-370
A spin model for cholestric liquid crystals is presented. The free energy is obtained in the mean field and from that the director correlation functions. It is found that one of the correlation functions diverges as (k32 + bk⊥4)?1 where k3 is the component of the wave-number parallel to the pitch axis, x⊥ the component perpendicular to the pitch axis and b is a constant. This divergence persists to all orders in the small parameter q0a where a is a molecular length and q0 is 2π over the pitch. This divergence implies that the cholesteric state is unstable with respect to fluctuations. 相似文献
18.
19.
P. Auger T. H. Chiang J. Galin B. Gatty D. Guerreau E. Nolte J. Pouthas X. Tarrago J. Girard 《Zeitschrift für Physik A Hadrons and Nuclei》1979,291(3):255-259
A non-relativistic quantum-mechanical system is studied which consists ofN identical bosons interacting by pair potentials of the form 〈r¦V¦r 1〉=?π/2ν 0 a ?3 f(r/a)f *(r 1/a). General upper and lower bounds to the ground-state energyE N are provided for alla, V 0 andN, and detailed results are given in the case of the Yamaguchi potential for whichf(x)=e ?x/x. It is shown that the ratioE N /E 2 diverges both under the limit (i) a↓0,E 2 =arbitrary constant <0, and (ii) (V 0 a 2)↓(V 0 a 2)c, where (V 0 a 2) c corresponds toE 2=0. The results complement recent studies of the Efimov effect via scattering theory. 相似文献
20.
The ground-state properties of the S = 1 Haldane- Shastry model are studied using a modified Lanczos algorithm and diagonalizing exactly small chains. We find evidence that, as for the antiferromagnetic Heisenberg model, the spectrum shows a gap, in contrast to the {ie1-1} case. The correlation functions < S z(0)S z(m) > decay exponentially for large m. We find that the correlation functions for the Haldane-Shastry model decay faster than for the Heisenberg model. We estimate the infinite system limit for the groundstate energy, value of the gap and correlation functions. 相似文献