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1.
Internal rotation A-E splittings have been observed in the ground state for both 35Cl and 37Cl isotopic species of S-methylchlorothioformate. The values V3 (35Cl) = 893 ± 20 and V3(37Cl) = 890 ± 20 cal/mole have been obtained. The anaalysis of the hyperfine structure gave χaa(35Cl) = ?49.2, χbb(35Cl) = 22.4 and χaa(37Cl) = ?39.0, χbb(37Cl) = 18.3 MHz. Only the syn-conformation of the methyl group with respect to the carbonyl group has been observed. A partial r0 structure is given.  相似文献   

2.
For the S = 12 XY model at T = 0 four susceptibilities have been calculated exactly on a sequence of finite square lattices and extrapolated to the infinite square lattice. For the ferromagnet χzz = 0 while χxxN2.9; for the antiferromagnet JχxxN(gμB)2 = 0.025 ± 0.002 and JχxxN(gμB)2 = 0.13 ± 0.03.  相似文献   

3.
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 a(Q2) = |αs(Q2)|(Re αs(Q2)/|αs(Q2)|)(n?2)3, where αs(Q2)n is the leading term in the spacelike region. For the intermediate range of Q2 experimentally accessible at present, where a(Q2) is significantly smaller than αs(|Q2|), we find the resulting phenomenology is improved. In particular, we demonstrate how the values of ΛMS obtained from analyses of quarkonium decays become consistent.  相似文献   

4.
Assuming that the sea quark distribution vanishes for x > 0.3, we analyse the F2Fe(x, Q2) and F2D(x, Q2) structure functions measured by the European Muon Collaboration in the framework of a thermodynamical model of the valence quarks. The experimental ratio F2Fe(x)F2D(x) is well reproduced over the whole x range by the ratio of two valence quark distributions at different temperatures T and confinement volumes V. We obtain TD?TFe≈3 MeV and VFeVD ≈ 1.3.  相似文献   

5.
Charge properties of the hadronic systems from νp and νp scattering in BEBC are studied in the framework of the quark-parto model (QPM). The average charges 〈Qjetν and 〈Qjetν of a quark jet and a d-qua jet, respectively, are determined according to two different methods. The difference 〈Qjetν ? 〈Qjetν is in agreement with e QPM value of 1. Scaling of charge and energy flow in the angular variable λ is demonstrated. The ratios ΔQν/ΔQν of charge flows in νp a νp scattering are in accord with the QPM in both hemispheres.  相似文献   

6.
If KS1,Lis a K1 resonance decaying into KS,L (the short- and long-lived kaon) and a neutral system So of pions, one can isolate the C-even and C-odd, crossed-channel contributions to KN → K1N by using the reactions KLN → KS1, LN whether So is a C-eigenstate, or a mixture of C-even and C-odd states. Applications to the production of K1(890) and the Q-meson are discussed, and simple numerical predictions made for QS,L production. Q-production data indicate approximate t-channel helicity conservation for the ω and P' exchanges at vertices involving a spin change, in similarity to the belief for the pomeron. QS,L production data can give information also on Q-decays.  相似文献   

7.
8.
It is shown that for spinorial charges Q(L))α (α = 1, 2, L = 1, …, S) satisfying the commutation relations
{Q(L)α, Q(M)β} = εαβaLMQ,
{Q(L)α, Q(M)+β} = cσμαβPμδLM,
[Q(L))α, Pμ] = 0,
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   

9.
The difference of the cross sections for deep inelastic scattering of muons with average momenta 21 GeV/c with right and left helicity at large angles, i.e., with large momentum transfer, has been measured. No statistically-significant dependence of cross sections on the longitudinal polarization of muons has been found, i.e. no parity-nonconservation effects in deep inelastic μN interaction have been observed. The magnitude of the cross-section asymmetry R = [〈σR〉 ? 〈σL〉][〈σR〉+ + 〈σL〉] may be represented as R = βQ2〉 = (? 4 ± 6) × 10?3Q2, (GeV/c)2〉. The limitations Go(μ) = (+ 6 ± 10)G have been obtained for the constant Go(μ) of vector-axial interaction (Go(μ)2) [μγα(1 + γ5)μ] Jαo (hadron, V-A).  相似文献   

10.
The massless electromagnetic Yang-Mills field is explicitly constructed as a linear combination EV3μ + (13) EV8μ of 16 gauge fields of the chiral SU(3) × SU(3) group within the framework of the plasmon generating mechanism [1]. The remaining 15 gauge fields acquire a mass through the non-zero vacuum expectation values of the auxiliary scalar multiplet which transforms according to the (8,8) representation of the gauge group. The tadpoles with non-zero hypercharge which are required for the existence of the only massless electromagnetic potential Aμ are due to the natural mixing of charged weak currents with ΔS = 0 and ΔS = 1. The relevance of this phenomenon to the Cabibbo angle is briefly discussed. Also presented is a theorem concerning an admissible form of the zero-order mass term of gauge fields when the canonical number is unknown.  相似文献   

11.
Nuclear spectroscopic quadrupole moments of the radioactive isotopes 131Cs, 132Cs, and 136Cs have been determined from the hyperfine structure of the 62P32 state by the level crossing method. The results including a Sternheimer correction are: Qs(131Cs) = ?0.625(6) b, Qs(132Cs) = +0.508(7) b, Qs(136Cs) = +0.225(10) b. The quadrupole moments of all the Cs isotopes from A = 131 to A = 137 are recalculated. It is shown, that nuclear quadrupole moments of a specific isotope obtained from different atomic P-states only agree within the limits of error after application of the Sternheimer correction. The increase of Qs with decreasing neutron number conforms with other observations and theoretical calculations stating that for elements around Z = 55 nuclear deformation develops below N = 82. The staggering of the sign of Qs may be interpreted as consequence of an oblate-prolate degeneracy of the nuclear energy surface. Some magnetic moments have been slightly improved: μI(132Cs) = 2.219(7) μN, μI(136Cs) = 3.705(15)μN (corrected for diamagnetism).  相似文献   

12.
The Callan-Gross relation is shown to be consistent with MIT-SLAC data for σL(Q2)σT(Q2) for x ? 0.33 in deep inelastic eN scattering, despite the fact that these data are taken in the large Q2 region where F1 and F2 individually exhibit scaling violation. Comparison is made with asymptotic freedom predictions, and color excitation is proposed to explain large values of σLσT at small x.  相似文献   

13.
We investigate transition strengths of right-handed weak charged currents in deep inelastic neutrino scattering, exploiting the dominance of p, n valence quarks in the nucleon. The energy dependence of σt and the average quantities 〈y〉 and 〈Q2〉 are shown to provide sensitive measures of new quark production thresholds and right-handed currents in νN scattering. With our analysis, the present data give an upper bound on the right to left hand structure function ratio of FRνNFLνN12, above a threshold of W≈7.5 GeV.  相似文献   

14.
The activation barrier ΔE1ABfor dissociation AB → A + B on transition-metal surfaces is analyzed within an additive Morse-type approach based on the bond-order conservation. It is shown that ΔE1AB = DAB?(QA + QB + QAQB/(QA + QB) where DAB is the gas-phase dissociation energy and QA(QB) is the heat of atomic chemisorption. Estimates of ΔE1 for H2, N2, O2, and NO are shown to be in reasonable agreement with experiment. The two-dimensional potential diagram of the metal-AB interactions is defined analytically and discussed in some detail.  相似文献   

15.
We study the correlation function 〈σ0x(t)σnx(0)〉 of the transverse Ising model in a critical field whose hamiltonian is 12Σllxσl+1xlz}. At an arbitrary temperature T we relate the autocorrelation to a Fredholm determinant. Moreover at T = 0 the correlations are given by a Painlevé V function for all n. The long-time asymptotic behavior of this function is found and the connection problem is studied. This result contains oscillatory terms which are related to the density of states at the Brillouin zone boundary.  相似文献   

16.
The order α(Q2) correction to the particle multiplicity ratio in gluon and quark jets is calculated in QCD. We find
r=941?αCA13+N?3CA?2N?CF3C2A
with r=〈ngluon jet/〈nquark jet. The method used is systematic and could be used for an order α(Q2) calculation.  相似文献   

17.
The hyperfine spectrum of KCl has been examined at near-zero electric field and zero magnetic field using a molecular beam electric resonance spectrometer. Rotational as well as vibrational shifts have been observed in both nuclear quadrupole interactions. With eqQ = Q00 + Q10(v + 12) + Q20(v + 12)2 + Q01J(J + 1), we find (all in units of kHz) for K in 39K35Cl: Q00 = ?5691.47 ± 0.04, Q10 = 51.32 ± 0.06, Q20 = ?0.205 ± 0.020, Q01 = 0.014 ± 0.007, Q00(K37Cl) ? Q00(K35Cl) = ?0.03 ± 0.07; for Cl in 39K35Cl: Q00 = 137.0 ± 0.3, Q10 = ?163.2 ± 0.5, Q20 = 1.57 ± 0.15, Q01 = 0.07 ± 0.03, [Q(35Cl)Q(37Cl)]Q00(K37Cl) ? Q00(K35Cl) = ?0.5 ± 0.6; and magnetic constants cK = 0.154 ± 0.007, cCl = 0.435 ± 0.010, c3 = 0.035 ± 0.012, and c4 = 0.009 ± 0.006. These have been used to provide a mapping of the field gradients at both nuclear sites to fourth order in ξ = (r ? re)re. We find eQqK(ξ) = (?5692.5 ± 2.5) + (1.7 ± 0.8) × 104ξ + (?2. ± 4.) × 104ξ2 + (?8. ± 18.) × 105ξ3 + (8. ± 15.) × 106ξ4 and eQqCl(ξ) = (120. ± 22.) + (8. ± 4.) × 104ξ + (?5.8 ± 2.0) × 105ξ2 + (?1.1 ± 1.6) × 107ξ3 + (1.1 ± 1.3) × 108ξ4.  相似文献   

18.
In an effort to develop a quantitative check of asymptotically free color-gauge theories, we analyze the logarithmic corrections to ξ-scaling coming from anomalous dimensions and coefficient functions of twist-two operators and compare with electroproduction data for 1 ? Q2 ? 16 GeV2. Excellent agreement is obtained using g2(2 GeV)2 = 0.17 for the effective quark-gluon coupling in the color-gauge theory. Effects of higher-twist operators are suppressed by powers of M02Q2. We use data from the resonance region to show M0 ? 400 MeV, in agreement with theoretical expectations. Our fit to νW2 in the scaling region also describes the resonance region in the sense of Bloom-gilman local duality. We show that local duality is a consequence of the moment predictions obtained from the operator-product expansion in quantum chromodynamics. We resolve a paradox associated with local duality and spin-zero targets. Present measurements of R = σLσT at large x and Q2 are systematically higher than our predictions.  相似文献   

19.
We prove a theorem concerning the energies of the 2S and 3D states in a potential V(r) = ?g2r + Vc(r), where Vc is a non-singular confining potential. If (ddr)3(r2Vc) is positive, then the 3D state lies above the 2S state, provided
ddr1rddr2Vc+rdVcdr < 0, ?r>0.
For Vc = rα, this corresponds to 0 < α < 2.  相似文献   

20.
We use semiclassical methods to discuss the scaling behaviour of quarkonium level splittings up to M(QQ) = 200 GeV. Special emphasis is laid on the effects of asymptotic freedom which are found to be essential for M(QQ) ? 30 GeV. The bound tt system will almost look like the ? system except that R = ΔM (3P2 ? 3P1)/ΔM(3P1 ? 3P0) is larger than 0.8. In the ? system R will already be close to 0.8.  相似文献   

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