共查询到20条相似文献,搜索用时 46 毫秒
1.
J. Kogut 《Physics letters. [Part B]》1974,51(4):383-386
Implications of recent measurements of the electron-positron annihilation cross section for other deep inelastic processes are discussed within the context of conventional field theory and conventional current algebra. Canonical scaling laws for deep inelastic electron and neutrino scattering are predicted to fail for . Other easily measured consequences of a violation of scale invariance at short distances are discussed. Comments and speculations concerning the renormalization group of strong interactions are made. 相似文献
2.
We describe a determination of the parton sea from pN → μ+μ?X via the Drell-Yan formula, making a minimum of theoretical assumptions. The method requires deep inelastic eN, μN structure functions to be extrapolated to suitable values of x, Q2. We determine the non-strange sea component between x = 0.2 and 0.5 with Q2 = x2s, and s = 750 GeV2. 相似文献
3.
D. Rein 《Physics letters. [Part B]》1973,43(3):209-212
Scaling observed in neutrino nucleon interactions at relatively low energies and not too small , is attributed to elastic scattering off three point-like, handed Zweig-Gell-Man valence quarks with low effective mass. The model predicts total inelastic cross sections all in agreement with available experiments. 相似文献
4.
The values of at q2=0 for the neutron and the proton provide a measure of the average transverse separations squared, 〈〉, between a u or d quark and the rest of the partons in a nucleon. Using the measured values of the form factors (together with parton x-distributions), we find that 〈 for u quarks and 16.4 GeV?2 for d quarks in a proton. We speculate that the small difference between u and d quarks is caused by “quark pairing” and discuss other possible experimental signatures of quark pairing. 相似文献
5.
Victor Elias 《Physics letters. [Part B]》1977,68(4):335-338
The Callan-Gross relation is shown to be consistent with MIT-SLAC data for 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 at small x. 相似文献
6.
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 for the effective quark-gluon coupling in the color-gauge theory. Effects of higher-twist operators are suppressed by powers of . We use data from the resonance region to show , 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 at large x and Q2 are systematically higher than our predictions. 相似文献
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8.
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 scattering. With our analysis, the present data give an upper bound on the right to left hand structure function ratio of , above a threshold of W≈7.5 GeV. 相似文献
9.
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
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11.
By also taking into account off-diagonal contributions to the virtual forward Compton amplitude, scaling in ep scattering is obtained from scaling of the total cross section for e+e? annihilation into hadrons. The parameter which sets the scale for the q2 dependence in ep scattering is calculated to be . 相似文献
12.
R.C. Fernow S.W. Gray A.D. Krisch H.E. Miettinen J.B. Roberts K.M. Terwilliger W. DeBoer E.F. Parker L.G. Ratner J.R. OFallon 《Physics letters. [Part B]》1974,52(2):243-246
The elastic cross section for proton proton scattering at 6 was measured using a 70% polarized beam and a 75% polarized target at the Argonne ZGS. In the range we obtained small error measurements for the ↑↑, ↓↓ and ↑↓ initial spin states perpendicular to the scattering plane. At P⊥2 = 0.5 we also measured the recoil spin and found that the 5 different cross sections were very unequal. 相似文献
13.
Masaki Yasuè 《Nuclear Physics B》1984,234(1):252-268
The masses of composite leptons and quarks are discussed in a “dynamical subquark model of pregauge interactions”. In this model, the leptons and quarks are made of a spinor and scalar subquark with equal mass, M, and the gauge bosons and Higgs scalar of the SU(3)c×SU(2)L×U(1)Y model are made of a subquark-antisubquark pair. The SU(2)L×U(1)Y symmetry is spontaneously broken by the composite Higgs scalar and the (scalar) subquark mass parameter is in turn bounded as is the Fermi coupling constant). The spontaneously generated mass of a lepton or quark, mi(n) (i = 1, 2; n = 1 ~ Ng), is calculated to be: are the parameters satisfying that 0 ? ri(n) ? 1 and Σ (ri(n))2 = 1;Ng is the total number of generations of the leptons and quarks; αe.m. is the fine structure constant. The appearance of light composite fermions is related to a specific mechanism of generating global chiral symmetries of the leptons and quarks. Global symmetries of scalar subquarks yield chiral symmetries of the leptons and quarks. Our model turns out to satisfy 't Hooft's anomaly conditions on massless composite fermions. 相似文献
14.
Otto Nachtmann 《Nuclear Physics B》1974,74(3):422-428
Recent experimental results on electroproduction off protons show that the ratio σ(ep → eK+Σ0)/σ(ep → eK+Λ) decreases strongly with increasing Q2. A simple argument is given in the framework of the quark parton model which could provide a qualitative understanding of this fact. The decrease of the Σ0/Λ ratio is related to the decrease of the ratio as Q2 increases, where are the usual structure functions for deep inelastic electron-nucleon scattering. 相似文献
15.
We use semiclassical methods to discuss the scaling behaviour of quarkonium level splittings up to . Special emphasis is laid on the effects of asymptotic freedom which are found to be essential for . The bound t system will almost look like the ? system except that is larger than 0.8. In the ? system R will already be close to 0.8. 相似文献
16.
The structure of hadronic final states in deep inelastic scattering expected from QCD is analyzed in terms of the shape parameters Hl and Cl. We find that the effects of the fragmentation of quarks and gluons into hadrons are typically governed by . For √s?30 GeV, the distributions of events in H2 and C2 should allow a test of the perturbative QCD prediction of three-jet events. 相似文献
17.
The average multiplicity in deep inelastic electro- and neutrinoproduction at large ω(ω~s/Q2 + 1) is related in Feynman's version of the parton model to the average multiplicities in high-energy electron-positron annihilation and hadron-hadron scattering. The relation is: , where Ce+e? and Ch are, respectively, the coefficients of ln(s/M1⊥2) in the multiplicities from e+-e? and P-P in to hadrons, and M1⊥ is an average transverse mass. 相似文献
18.
M.G. Albrow A. Bagchus D.P. Barber A. Bogaerts B. Bošnjaković J.R. Brooks A.B. Clegg F.C. Erné C.N.P. Gee D.H. Locke F.K. Loebinger P.G. Murphy A. Rudge J.C. Sens F. van der Veen 《Nuclear Physics B》1974,72(3):376-392
Results are reported of measurements of the momentum spectra of protons emitted at small angles in inelastic reactions at the CERN ISR. The data are for total energies of 23 GeV and 31 GeV. The structure of the peak at low values of the missing mass M (of the system recoiling against the observed proton) is studied. The missing mass distributions have the form (M2)?B(t) where t is the four-momentum transfer squared. B(t) drops from 0.98±0.06 at t=?0.15 GeV2 to 0.20±0.15 at t=?1.65 GeV2. The results are compared with a simple triple-Regge formula. 相似文献
19.
Yu.B. Bushnin A.F. Dunaitsev R.I. Dzelyadin S.V. Golovkin V.F. Konstantinov V.P. Kubarovsky L.G. Landsberg V.M. Leontiev G.P. Makarov V.A. Mukhin V.G. Rybakov T.I. Petrunina Yu.N. Simonov V.V. Smirnov A.M. Zaitsev A. Zallo 《Physics letters. [Part B]》1976,64(1):102-106
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 may be represented as R = β〈Q2〉 = (? 4 ± 6) × 10?3 〈Q2, (GeV/c)2〉. The limitations Go(μ) = (+ 6 ± 10)G have been obtained for the constant Go(μ) of vector-axial interaction (hadron, V-A). 相似文献
20.
A. Ali 《Physics letters. [Part B]》1982,110(1):67-72
The QCD effective coupling constant αs(Q2) is determined by comparing the O(αs)2 jet-distributions with the high-energy e+e? data from PETRA. We get αs(Q2 = 1225 GeV2) = 0.125 ± 0.01, which corresponds to with five flavours. 相似文献