共查询到20条相似文献,搜索用时 15 毫秒
1.
On the basis of the known group theoretical structure of the conformal invariant four point functions in the case of identical scalar fields ?(x) of scale dimension d, the analytical properties of g(A, B) as a function of the harmonic ratios A and B are investigated. By imposing the conditions of spectrality and locality, and using invariance under complex dilatations, it is shown that the function g(A, B) must be homomorphic in the whole complex A-plane and B-plane with exception of the values A=0 and A=∞, B arbitrary, and B=0 and B=∞, A arbitrary. 相似文献
2.
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
3.
We calculate the simplest one-instanton correction to the perturbative QCD prediction for e+e? annihilation to hadrons. At high centre-of-mass energies Q we find a contribution to the total cross section from a simple fermion loop of the form where Nf is the number of quark flavours. The numerical value of this contribution is O(1) for Q ~ 1 to 2 GeV. 相似文献
4.
G.C. Salzman Gerald G. Ohlsen J.C. Martin J.J. Jarmer T.R. Donoghue 《Nuclear Physics A》1974,222(3):512-524
Angular distributions of six polarization transfer coefficients ; of the four analyzing powers Ay(θ), Axx(θ), Ayy(θ), and Azz(θ); and of the polarization function Pý(θ), have been measured atEd = 10.00 MeV for the reaction 2H(d, n)3He. Measurements were made for neutron lab angles between 0° and 80° in 10° steps. Additionally the y-axis associated quantities were measured at θ1ab = 99°. Most of the measured coefficients are large at some angles and all show considerable variation with angle. 相似文献
5.
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
6.
J.C.D. Brand U.D. Deshpande A.R. Hoy S.M. Jaywant 《Journal of Molecular Spectroscopy》1983,100(1):143-150
The E-B (0g+-0u+) band system of Br2 has been investigated at Doppler-limited resolution using polarization labeling spectroscopy. Merged E state data for the three naturally occurring isotopes in the range vE = 0–16, expressed in terms of the constants for 79Br2, are (in cm?1) Y0,0 = 49 777.962(54), Y1,0 = 150.834(22), Y2,0 = ?0.4182(28), Y3,0 = 6.6(11) × 10?4, Y0,1 = 4.1876(28) × 10?2, Y1,1 = ?1.607(16) × 10?4, and Y0,2 = 1.39(39) × 10?8. The bond distance is , and the diabatic dissociation energy to . 相似文献
7.
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 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 . 相似文献
8.
H.H. Bingham C.W. Farwell W.B. Fretter G.M. Irwin S. Kahn A. Lu B. Daugeras D. Fournier J. Hennessy M. Novak J.J. Veillet A.M. Cnops F.R. Huson R.I. Louttit D.J. Miller J.S. ONeall M. Di Carato M. Rollier J. Ginestet 《Nuclear Physics B》1973,52(1):31-69
Coherent production of final states from A ~ 20 nuclei by K? beams of 5.5, 10.0 and 12.7 GeV is analyzed. Final states with ? 2πO are included. Coherent production occurs (although forbidden via 0+ exchange) and is dominated by the 1 (890). The shape of the t distribution, the alignment of the produced meson and the ratio of the cross section on nuclei to that on hydrogen are consistent with optical model predictions assuming that 1 (890) are produced on single nucleons by exchange of isoscalar trajectories of natural parity (JP = 1?, 2+, etc.) and that the 1 (890) absorption in nuclear matter equals that of the K?. Coherent production (allowed via 0+, 1?, 2+, etc. exchange) is dominated by the Q phenomenon. A Dalitz plot and angular correlation analysis yields values for fractions, and shows that dominates the coherently produced Q. The helicity of the Q is found to be compatible with 0. The Q? -nucleaon total cross section is estimated to be 0.98?0.37+024 times the ? -nucleon total cross section from a comparison of the coherent Q-production cross section with corresponding hydrogen cross sections at 10 and 12.7 GeV. We observe coherent production of ω. The ration coherently produced in the Q mass region is (4 ± 1)%. Coherent production of is observed in the L region. Coherent production is not observed in the K4π channels. 相似文献
9.
H.G. Kirk R. Schulte P. Sixel M. Klein M. Walter M.J. Counihan D.J. Kocher P. Kostka P.K. Malhotra D.R.O. Morrison H. Saarikko K.L. Wernhard K.W.J. Barnham R.M. Eason D.P. Dallman F. Mandl M. Markytan 《Nuclear Physics B》1976,116(1):99-117
The inclusive production of K?1(890) and K?1(1420) is studied in K??p interactions at 10 and 16 GeV/c. At 10 GeV/c an enhancement in the () mass distribution is found at 1.74 GeV, but no clear signal is seen at 16 GeV/c. The fraction of coming from decay of the is large, being (50 ± 6)% and (45 ± 5)% at 10 and 16 GeV/c, respectively. The inclusive cross sections for K1?(890) and production are almost constant with energy from 8 to 32 GeV/c with values of 3.5 and 3.3 mb, respectively. The production cross section is studied as a function of transverse and longitudinal variables and found to derive mainly from fragmentation of the incident K? meson. The spectra of resulting from the decay of are studied. 相似文献
10.
The renormalization group approach is applied to the study of transverse momentum distribution of partons in QCD. We generalize the method of Altarelli and Parisi to obtain a formula for the mean squared average transverse momentum as a function of Q2 and x, the virtual photon mass squared and the longitudinal momentum fraction of the parton. For large Q2, it decreases with x in addition to the expected increase with Q2. This x-dependence reduces substantially the transverse momentum of massive μ-pairs produced by hadronic collisions from its linear dependence on . 相似文献
11.
R. Barloutaud A. Borg F. Brun D. Denegri C. Louedec F. Pierre M. Spiro B. Drevillon B. Chaurand G. Labrosse R. Lestienne D. Linglin R.A. Salmeron T.P. Shah K. Paler R.J. Miller J.J. Phelan 《Nuclear Physics B》1973,59(2):374-411
We have studied the system in the 14.3 GeV/c reactions K?p → K?π+π?p, . The data have been obtained from a 500 000 picture exposure of the CERN 2m HBC. The first two final states are dominated by Q-production in the Kππ system; there is also an L-signal at M (Kππ) ~ 1.75 GeV. The reaction cross sections are compared to K?p data at other energies. We discuss the Kππ mass dependence of the diffractive production slope. Evidence is presented for a Q?p versus Q+p differential cross section cross-over around |t| = 0.17 GeV2. A t-channel isospin analysis for the channels in the Q-region shows that the I = 1 exchange amplitude is of the dominant I = 0 exchange amplitude. The Kππ decay distributions indicate a predominant JP = 1+ state in the Q-region, and an important JP = 2? contribution in the L-region. We find neither s-channel nor t-channel helicity conservation at the meson vertex in the Q- or L-regions. The Kπ angular correlation moments within the Kππ diffractive system are characteristic of Kπ elastic scattering, suggesting a π-exchange Deck-type production mechanism. There is evidence for a Kf0 and κπ contribution (where κ is the JP(Kπ) = 0+ state) to the diffractive Kππ system. A fit to the Dalitz-plot distributions for the Q-re gion indicates that the ratio of decay amplitudes decreases with increasing Kππ mass. 相似文献
12.
C.G. Wohl R. Barloutaud A. Borg D. Denegri Y. Pons M. Spiro K. Paler C. Comber S.N. Tovey B. Chaurand B. Drevillon J.M. Gago R.A. Salmeron 《Nuclear Physics B》1978,132(5):401-428
We present experimental results on a number of K?p reactions at 14.3 GeV/c that have three bodies in the final state. The final states are . Whenever, with one exception explained by the Zweig rule, there is a K? or a proton in the final state, there is a diffractive-like threshold enhancement in the mass spectrum of the two recoiling particles. These enhancements account for a large fraction of the events in all but the Λπ+π? final state, where they cannot occur, and which is dominated by resonance production. We find evidence for the Q1(1300) decaying into K?ω. 相似文献
13.
M.J. Corden J.D. Dowell D. Eastwood J. Garvey R.J. Homer M. Jobes I.R. Kenyon T. McMahon R.J. Vallance P.M. Watkins J.A. Wilson J. Gago M. Jung P. Sonderegger D. Treille P.L. Woodworth V. Eckardt J. Fent K.C.T.O. Sumorok 《Physics letters. [Part B]》1977,68(1):96-100
Measurements have been made of relative production cross sections of the by π±, K±, p and p? at 39.5 GeV/c incident on copper. production rates from π?, K? and p? are similar. The relative particle/anti-particle production cross sections for x>0 are , σ(K+)/σ(K?)=(0.85±0.5) and . The small p/p? cross section ratio disagrees with models of J/ψ production by gluon amalgamation. 相似文献
14.
Takehiko Tanaka Robert W. Field David O. Harris 《Journal of Molecular Spectroscopy》1975,56(2):188-199
A rotational assignment of approximately 80 lines with Ka′ = 0, 1, 2, 3, and 4 has been made of the 593 nm band of NO2 using cw dye laser excitation and microwave optical double-resonance spectroscopy. Rotational constants for the 2B2 state were obtained as A = 8.52 cm?1, B = 0.458 cm?1, and C = 0.388 cm?1. Spin splittings for the Ka′ = 0 excited state levels fit a simple symmetric top formula and give . Spin splittings for Ka′ = 1 (N′ even) are irregular and are shown to change sign between N′ = 6 and 8. Assuming that the large inertial defect of 4.66 amu Å2 arises solely from A, a structure for the 2B2 state is obtained which gives and an ONO angle of 105°. Alternatively, weighting the three rotational constants equally gives and θ = 118°. 相似文献
15.
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
16.
David Nitz James Cederberg Arthur Kotz Keith Hetzler Thor Aakre Timothy Walhout 《Journal of Molecular Spectroscopy》1984,108(1):6-16
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 , 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, ; 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 . 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
17.
The nature of mesons in the 0++ nonet is studied. In particular we discuss the parameterization of the I = 0 S wave in terms of the S1 and possible ? mesons. The S1 parameters are determined by fitting to π?π+ and K?K+ production data. In particular we find . 相似文献
18.
C. Cochet C. Lewin R. Barloutaud D. Denegri A. Givernaud M.L. Turluer U. Gensch U. Kriegel H. Vogt H. Kirk D.R.O. Morrison H. Saarikko F.A. Triantis Yu. Arestov E.P. Kistenev E.A. Kozlovsky A.M. Moïseev F. Mandl 《Nuclear Physics B》1979,155(2):333-356
Inclusive production of vector and tensor mesons is studied in a K?p experiment at 32 GeV/c in the MIRABELLE bubble chamber. The , ?0 and ω cross sections are comparable, about 4 mb each. The and cross sections are also comparable, about 1 mb each. The (890), Φ, (1420) and f cross sections beam fragmentation; ? production is almost forward-backward symmetric in the c.m.s. The pT production slopes of and ? are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ?50% (?60%) of final-state pions 相似文献
19.
Nobukimi Ohashi Masao Kakimoto Shuji Saito Eizi Hirota 《Journal of Molecular Spectroscopy》1980,84(1):204-224
The vibronic transition (16 370 to 16 425 cm?1) of the DSO radical in studied by Doppler-limited dye laser excitation spectroscopy. DSO is produced in a flow system by reacting the products of a microwave discharge in O2 with D2S. About 637 observed lines are assigned to 987 transitions of the 19 subbands: K′a ← K″a = 6 ← 5, 5 ← 4, 4 ← 3, 3 ← 2, 2 ← 1, 1 ← 0, 0 ← 1, 1 ← 2, 2 ← 3, 3 ← 4, 0 ← 0, 1 ← 1, 2 ← 2, 3 ← 3, 4 ← 4, 3 ← 1, 2 ← 0, 0 ← 2, and 1 ← 3. They are analyzed to determine rotational constants, centrifugal distortion constants, and spin-rotation constants for both the ground and the excited electronic states. The band origin obtained is 16 413.874 (2.5σ = 0.002) cm?1. The rotational constants determined are combined with the previous result on HSO (M. Kakimoto et al., J. Mol. Spectrosc.80, 334–350 (1980)) to calculate the structural parameters for this radical in both the states: , , and ∠HSO = 106.6(5)° for the state, and , , and ∠HSO = 95.7(21)° for the state, where values in parentheses denote 2.5σ. 相似文献
20.
The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a transition from Fe2+ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes and , respectively, which take into account Fe 3dn?1 final state effects. 相似文献