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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   

5.
Sub-Doppler optical-optical double-resonance excitation spectra of BaF were recorded using two single-mode cw dye lasers. In the 30 000-cm?1 region, the electronic states observed were E2Σ+ and F2Π. The latter had been previously assigned as the “F2Σ+” state by Fowler [Phys. Rev.59, 645–652 (1941)]. The (3, 0) and (4, 0) bands of the E2Σ+-B2Σ+ transition and the (1, 0) and (2, 0) bands of the F2Π-B2Σ+ transition were rotationally analyzed. The molecular constants suggest inferences about the dominant atomic orbital character of the Rydberg molecular orbitals responsible for the E2Σ+ and F2Π electronic states. A new electronic state, the E′ 2Π, is predicted. The molecular parameters obtained (in cm?1, 1σ uncertainty in parentheses) are
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6.
Experimentally, it is much easier to measure structure functions at fixed hadron energy Eh, rather than at fixed Q2. We prove the sum rules
?10dx F3|fixed Eh= 3 1 ? (1+hNS) αs(s)π,
?10dx F2|fixed Eh= 3nf16+3nf1?171+44nf9(67?12nf+ hSαs(s)π + Kαs(s)π0.75
,
hNS=43(16π2 ? 58),
hS=416+3nf (2π2 + 16π2nf?6512?572nf).
Here s = 2mpEh and F2,3 are the standard functions for scattering of neutrinos on an isoscalar target. K is an unknown constant, and the corrections to the sum rules are O(αs2), O(αs1.75), respectively.  相似文献   

7.
The mutual perturbations of the A1Σu+ and b0u+ states of As2 are due to a strong spin-orbit interaction. The numerical treatment of these perturbations leads to the following parameters:
v′EE2Σ+v′FF2Π
Tv′0329 767.32(1)129 997.29(1)
ΔGv′ + 123522.841(27)1522.553(2)
Be0.22990(22)0.22931(8)
αe0.00113(14)0.00108(2)
Av′156.9840(12)
pv′1?0.02426(6)
γv′3?0.17367(46)
  相似文献   

8.
The small ω′ behaviour of F2en/F2ep and the apparent difference in the q2 dependences of the magnetic form factor of the proton and of the transition to Δ+(1236) are quantitatively correlated in a model where nucleon consistes of a quarks and a scalar or vector core. The proton and Δ transition form factors suggest that only the scalar core contributes at large q2 and small ω′. As a result the ω′ dependence of F2enF2ep is obtained for ω′ < 3 and predictions for the weak structure functions and polarisation asymmetries at smallω′ are presented. We predict FνpFνnω′→10 asymmetries ω′→11 and also expect that GmnGmp?12 as q2→∞.  相似文献   

9.
A synthetic germanium-doped crystal of α-quartz was subjected to an electro-diffusion process ca. 600Vcm, 625°K), in which Ag+ ions were introduced along the crystal's optic axis (c). A 9800MHz electron paramagnetic resonance spectrum at room temperature, taken after room temperature x-irradiation, revealed the presence of a silver-compensated germanium center AGe?Ag with large, almost isotropic 107Ag and 109Ag hyperfine splittings (26.078, 30.112 mT for magnetic field B∥c). Measurement of the spin-Hamiltonian (i.e. matrices g, A73Ge, A107Ag and A109Ag) discloses that a suitable model for the observed center utilizes germanium, substituted for silicon, with the accompanying silver interstitial in a nearby c-axis channel, and with electronic structure in which an appreciable admixture Ge4+?Ag0 to Ge3+?Ag+ exists. Estimates of the unpaired electron orbital are presented.  相似文献   

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The absolute vibrational numbering of the Na2b3Πu state has been established by direct observation of the v = 0–13 levels. These b3Πu levels appear as the lower levels in rotationally resolved fluorescence spectra resulting from OODR excitation of 3Πg, 3Δg, and 3Σg+ states via b3ΠuA1Σu+ mixed intermediate levels. The molecular constants for the Na2b3Πu state are (in cm?1, one standard error in parentheses)
Te (cm?1)ωe (cm?1)ωexe (cm?1)Be (cm?1)
A1Σu+40 806 (3)297 (2)5.1 (2)0.0798 (12)
b0u+38 884 (3)422 (1)8.8 (1)0.0783 (12)
  相似文献   

13.
Based on the proper connected diagram expansion, we calculated cyclotron resonance widths Γn associated with neighboring Landau states (n, n +1) for free electrons in interaction with more than one kind of impurities. In 3D usual Matthiessen's rule Γn=Γ(1)n+Γ(2)n+…where Γ(i)n represent widths calculated separately for each kind, is obtained. In 2D a new rule: Γn=[Γ(1)2n(2)2n+…]12 is obtained.  相似文献   

14.
Let g denote the Lie superalgebra sl(n, 1). Its even part is the Lie algebra g0=gl(n) of n×n complex matrices. Let
denote the reductive subalgebra gl(p)⊕gl(q) in g0, p+q=n. We show that for a certain set Λ+0 of irreducible finite dimensional
-modules there exists, for each λ?Λ+0, an irreducible
-finite g-module (which is unique up to equivalence) with minimal
- type λ.  相似文献   

15.
An n-orbital model describing both elastic impurity scattering and exchange interaction is examined near its instability for itinerant ferromagnetism. At the critical point and at zero temperature, long range spin fluctuations cause anomalous enhancements of the density of states near the Fermi energy with ?(E) - ?(EF) ∝ |E ? EF|14 in three-dimensions (3D) and with ln2|E ? EF| in 2D. An estimation of the conductivity σ(Ω) in a continuum analog model reveals Ω14 -and ln2τ|-corrections in 3D and 2D respectively.  相似文献   

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The transverse spin pair correlation function pxn=<SxmSxm+n>=<SxmSxm+n> is calculated exactly in the thermodynamic limit of the system described by the one-dimensional, isotropic, spin-12, XY Hamiltonian
H=?2Jl=1N(SxlSxl+1+SylSyl+1)
. It is found that at absolute zero temperature (T = 0), the correlation function ρxn for n ≥ 0 is given by
ρx2p=142π2pΠj=1p?14j24j2?12p?2jif n=2p
,
ρx2p+1142π2p+1Πj=1p4j24j2?12p+2jif n=2p+1
, where the plus sign applies when J is positive and the minus sign applies when J is negative. From these the asymptotic behavior as n → ∞ of |?xn| at T = 0 is derived to be xn| ~ an with a = 0.147088?. For finite temperatures, ρxn is calculated numerically. By using the results for ?xn, the transverse inverse correlation length and the wavenumber dependent transverse spin pair correlation function are also calculated exactly.  相似文献   

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The He2 band systems 4pπ i3Πg → 2s a3Σu+ and 5pπ l3Πg → 2s a3Σu+ are described in detail, and the i and l states characterized. A number of significant perturbations in the i and l states are identified, and the possible perturber states discussed. The following molecular constants (cm?1) are reported:
Te13 517.2 (1.3)Be0.1434 (0.0027)
ωe153.6 (1.1)αe9×10?5 (4×10?4)
ωeξe0.47 (0.09)re3.20 (0.03) Å
Ae7.85 (0.60)αA0.19 (0.16)
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20.
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 F1γn/F1γp as Q2 increases, where F1γp and F1γn are the usual structure functions for deep inelastic electron-nucleon scattering.  相似文献   

StateωeeBeαere (A?)
i3Πg1707.9535.007.242g0.2221.0782
l2Πg1703.8634.977.22640.21881.0794
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