共查询到20条相似文献,搜索用时 46 毫秒
1.
Jan T. łopuszański 《Reports on Mathematical Physics》1976,9(3):301-307
It is shown that for spinorial charges Q(L))α (α = 1, 2, L = 1, …, S) satisfying the commutation relations where Q is a scalar charge commuting with the spinor charges as well aswith the energy- momentum vector Pμ, there can exist several different multiplets for free massive scalar and spinor fields. 相似文献
2.
R.A. Brandt 《Nuclear Physics B》1976,116(2):413-448
The renormalization of Abelian and non-Abelian local gauge theories is discussed. It is recalled that whereas Abelian gauge theories are invariant to local c-number gauge transformations δAμ(x) = ?μ,…, with □Λ = 0, and to the operator gauge transformation δAμ(x) = ?μφ(x), …, δφ(x) = α?1?·A(x), with □φ = 0, non-Abelian gauge theories are invariant only to the operator gauge transformations , …, introduced by Becchi, Rouet and Stora, where μ is the covariant derivative matrix and C is the vector of ghost fields. The renormalization of these gauge transformation is discussed in a formal way, assuming that a gauge-invariant regularization is present. The naive renormalized local non-Abelian c-number gauge transformation , …, is never a symmetry transformation and is never finite in perturbation theory. Only for with L finite constants or for with Ω a finite constant does it become a finite symmetry transformation, where is the ghost field renormalization constant. The renormalized non-Abelian Ward-Takahashi (Slavnov-Taylor) identities are consequences of the invariance of the renormalized gauge theory to this formation. It is also shown how the symmetry generators are renormalized, how photons appear as Goldstone bosons, how the (non-multiplicatively renormalizable) composite operator Aμ × C is renormalized, and how an Abelian c-number gauge symmetry may be reinstated in the exact solution of many asymptotically fr ee non-Abelian gauge theories. 相似文献
3.
The dependence of the low-lying spectra of hypernuclei on hyperon-α interaction in the molecular α + α + Λ(Σ) scheme has been studied. A suggestion is made for obtaining the strengths of both p-wave and spin-orbit Λ-α interactions from the experimental spectrum. A relation between the Σ0-binding energies and has been established and on its basis a prediction is made about a possible binding energy of . 相似文献
4.
From the scaling law for the s-channel partial wave amplitudes, which guarantees simultaneously t-channel unitarity at threshold t = 4μ2 and s-channel unitarity, we derive: (i) The intercept α(0) of the Pomeron is always one, if α(4μ2) > 1. (ii) The total and the elastic cross sections are bounded from below for s → ∞. where α(4μ2) and δ(4μ2) are the position and the type of te Pomeron singularity (J ? α(4μ2))?1?δ(4μ2) at t = 4μ2. (iii) The type of the Pomeron singularity δ(4μ2) is restricted: either or . 相似文献
5.
We have obtained a least upper bound, , on the critical temperature Tc of an isotropic superconductor with paramagnetic impurities described by the scattering matrix t for fixed values of μ1. We have also obtained the corresponding optimal spectrum . The numerical results for the functions are presented for and 0.16 in the form of universal curves representing as functions of the reduced impurity concentration . We have also established an upper limit to the reduced critical concentration for an arbitrary shape of α2F(ω)1. 相似文献
6.
The exact vanishing of all β functions of the Callan-Symanzik equation is proved in a two-dimensional model with Thirring and gradient couplings: , and , where ψ, π and σ are fermion, pseudoscalar and scalar massive fields, respectively. The anomalous dimensions of scalar and pseudoscalar fields are also shown to be zero. Then we demonstrate that in two-dimensional models including at most one fermion field, only these three couplings can give asymptotic scale invariance. 相似文献
7.
R.M. Macfarlane 《Solid State Communications》1974,15(3):535-538
We have observed inter-term Raman scattering from 5T2g→5Eg Frenkel excitons in antiferromagnetic FeF2. It differs qualitatively from previously observed intra-term scattering in a sharply reduced zero-phonon cross section and the appearance of relatively strong exciton-phonon scattering. Since the Raman process is fully allowed, it is possible to measure excited state Debye-Waller factors, D, and we find and . 相似文献
8.
A. Possoz Ph. Deschepper L. Grenacs P. Lebrun J. Lehmann L. Palffy A. De Moura Gonçalves C. Samour V.L. Telegdi 《Physics letters. [Part B]》1977,70(2):265-268
The helicity, h?, of μ? in π-decay has been determined as positive (h??+0.90) from the average polarization, Pav≡〈JB·sμ〉, of 12B produced in the reaction. We obtain also dynamical information on μ-capture: (i) the weak magnetism form factor, μ=4.5±1.1, and (ii) the sum of the induced pseudoscalar (gp) and the 2nd class induced tensor (gT) couplings versus gA, (. The latter result, adopting the “canonical” value of , leads to which is compatible with zero and in strong contradiction with the value ?—6 recently advocated by Kubodera, Delorme and Rho. 相似文献
9.
The Coriolis resonance between ν4 and ν7 in CH3CN and between ν1 and ν5, ν3 and ν6, and ν4 and ν7 in CD3CN has been analyzed, applying the technique developed by DiLauro and Mills, to obtain the signs of [] and the ratio of to for the interacting pairs in CD3CN. For (ν4, ν7) in both CH3CN and CD3CN, the sign of [] is found to be negative as it is also for (ν1, ν5) in CD3CN. For (ν3, ν6) the sign of this interaction term is found to be positive. For a given definition of normal coordinates the signs of these interaction terms give the relative signs of and ; our study also gives approximate values for the corresponding ratio [] 相似文献
10.
G.W. Brandenburg W.B. Johnson D.W.G.S. Leith J.S. Loos J.A.J. Matthews F.C. Winkelmann R.J. Yamartino 《Physics letters. [Part B]》1973,44(3):305-309
Differential cross sections for center of mass scattering angles near 90° are presented for the reactions , and KL°p → KS°p in the momentum interval 1.0 to 7.5 GeV/c. The energy dependences of these cross sections are found to be equally well described by the parameterization: or . 相似文献
11.
C.R. Leavens 《Solid State Communications》1975,17(12):1499-1504
It is rigorously shown that the superconducting transition temperature of any material for which the Eliashberg theory is valid must satisfy kBTc ? 0.2309 A, where A is the area under its electron-phonon spectral function α2F(ω). This relation is a least upper bound, not just an upper bound, in the sense that there is an optimal situation in which the equality holds. This occurs when the Coulomb pseudopotential parameter is zero and the spectral function is the Einstein spectrum Aδ(ω ? 1.750 A). These results are generalized in an approximate, but sufficiently accurate, way to the case to obtain the more useful least upper bound and the corresponding optimal spectrum . Numerical results for the functions and d(μ1) are presented for . It is shown that the Tc's of many materials (including Nb3Sn), for which experimental values of A and are available, do not lie very far below the upper bound. 相似文献
12.
The predictions of perturbative QCD are derived in the deep euclidean region, whereas the physical region for most observables is timelike. The confrontation of these predictions with experiment thus necessitates an analytic continuation. This we find introduces large higher order corrections in terms of αs(|Q2|), the usual choice ofperturbative expansion parameter. These corrections are naturally absorbed by changing to the expansion parameter , where αs(Q2)n is the leading term in the spacelike region. For the intermediate range of Q2 experimentally accessible at present, where is significantly smaller than αs(|Q2|), we find the resulting phenomenology is improved. In particular, we demonstrate how the values of obtained from analyses of quarkonium decays become consistent. 相似文献
13.
Robert S. Mulliken 《Journal of Molecular Spectroscopy》1976,61(1):92-99
Predissociations in the y1Πg and Rydberg states of N2 (configurations and , respectively) and their likely causes, are discussed. Peaking of rotational intensity at unusually low J values, without sharp breaking off, is interpreted as due to case c? or case ci predissociation. Λ doubling in the y state, attributed to interactions with the state and with another, 1Σ+, state of the same electron configuration as x, is analyzed. From this analysis the location of the (unobserved) state, here labeled x′, is obtained. It is concluded that the predissociation in the Π+ levels of the y state is an indirect one mediated by the interaction with x′ coupled with predissociation of x′ by a state dissociating to atoms: combined, however, with perturbation of the y state by the k1Πg Rydberg state (configuration ), whose Π+ levels are completely predissociated. 相似文献
14.
Compactified Minkowski space can be embedded in projective five-space CP5 (homogeneous coordinates Xi, i = 0, …, 5) as a four dimensional quadric hypersurface given by Projective twistor space (homogeneous coordinates Zα, α = 0, …, 3) arises via the Klein representation as the space of two-planes lying on this quadric. These two facts of projective geometry form the basis for the construction of a global space-time calculus which makes use of the coordinates Xi?Xαβ(=-Xβα) to represent spinor and tensor fields in a manifestly conformally covariant form. This calculus can be regarded as a synthesis of work on conformal geometry by Veblen, Dirac, and others, with the theory of twistors developed by Penrose.We provide here a systematic review of the basic framework: the underlying projective geometry; the calculus of tensor fields; the characterization of spinors as twistor-valued fields ψα(X) which satisfy a geometrical condition ( ); and the introduction of the conformally invariant Laplacian operator . In addition a number of subsidiary topics are discussed which illustrate the general scheme, including: the breaking of conformal symmetry to Poincaré symmetry; a derivation of the zero rest mass equations for all helicities; and a new and manifestly conformally covariant form of the twistor contour integral formulae for massless fields. 相似文献
15.
J.P. Gazeau 《Physics letters. A》1980,75(3):159-163
The equivalence between the bound-state problem for the spatial harmonic oscillator and for the Coulomb potential is reexamined and extended: a similar duality is displayed between large classes of confining potentials and (R+L∞?) potentials, i.e., potentials for which the Schrödinger operator has among other properties a discrete spectrum bounded below, in (-∞, 0). The involved confining potentials U(r) must satisfy: . 相似文献
16.
17.
H. Roos 《Reports on Mathematical Physics》1978,14(2):161-170
A microcanonical system oΛ is considered together with a manometer Λ. The thermodynamic limit Λ → ∞ is taken for the system Λ composed of oΛ and Λ. This yields a definition of the pressure P(v, ε) of for given values ε and v of the energy and particle densities. P(v, ε) is shown to be equal to the thermodynamic function p(z, β) derived from the grand canonical ensemble for almost all values of ε and v provided the appropriate equilibrium values of the temperature β?1 and the chemical potential μ = β?1 log z are inserted. 相似文献
18.
H. Kleinert 《Physics letters. [Part B]》1976,62(1):77-80
In quark gluon theory with very small bare masses, -ψ, spontaneous breakdown of chiral symmetry generates sizable masses Mu, Md, Ms, … We find (. Scalar densities have well determined non-zero vaccum expectations at an SU(3) breaking of the vacuum c′ ≡ 〈0|u8|〉/〈0|uo|0〉 ≈ ? 16% 相似文献
19.
The one-electron momentum distribution function for an electron gas is investigated by a diagrammatic analysis of perturbation theory. It is shown that has the following exact asymptotic form for large k (k ? pF; pF, the Fermi momentum): , where g?(0) is the zero-distance value of the spin-up-spin-down pair correlation function. The physical implications of the above asymptotic form are discussed. 相似文献
20.
The non-selective nature of the (α, nγ) reaction has been used to complement information from charged-particle reactions on the level structure of 88Y and 90Y. The γ-ray spectra were recorded with a 25 cm3 Ge(Li) detector at 90° to the beam using primarily targets of 85Rb2CO3 and 87Rb2CO3 and α-particle energies of 11.8, 12.2 and 13.0 MeV. The resulting transitions were accommodated in level schemes that involved primarily the following shell model configurations: , , , in 88Y and , , in 90Y. 相似文献