相关论文: Experimental study of isovector spin sum rules
The Drell-Hearn-Gerasimov and Bjorken sum rules are special examples of dispersive sum rules for the spin-dependent structure function G_1(\nu, Q^2) at Q^2=0 and \infty. We generalize these sum rules through studying the virtual-photon…
We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 0.7 < Q^2 < 20 GeV^2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons…
The ratio g1/F1 has been measured over the range 0.03<x<0.6 and 0.3<Q2<10 (GeV/c)2 using deep-inelastic scattering of polarized electrons from polarized protons and deuterons. We find g1/F1 to be consistent with no Q2-dependence at fixed x…
We present progress in the QCD analysis of the Bjorken sum rule at low momentum transfers. We study asymptotic structure of the perturbative QCD expansion at low $Q^2$ scales based on analysis of recent accurate data on the Bjorken sum rule…
We present details of study of the Bjorken polarized sum rule carried out recently in [1] within the range of energies where the data were collected by JLAB collaboration, 0.05 GeV2 < Q2 < 3 GeV2. Three approaches to QCD with analytic…
The power correction, surviving the zero quark mass limit and found earlier to restore the validity of Burkhardt-Cottingham sum rule, provides the contribution to the Bjorken sum rule as well. The leading perturbative correction to the…
The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive $\pi^0$ production in a wide kinematic region with the photon virtualities $Q^2$ up to 8 GeV$^2$ and the Bjorken scaling variable $x_B$…
The experiment E155 at SLAC measured the spin structure functions g_1 and g_2 of the proton and deuteron. The experiment used deep inelastic scattering of 48.3 GeV longitudinally polarized electrons incident on polarized solid ^{15}NH_3 and…
In the near future, the Jefferson Lab $b_1$ experiment will provide the second measurement of tensor polarized asymmetries in inclusive DIS on the deuteron. In this asymmetry, 4 independent tensor polarized structure functions contribute.…
We generalize the sum rules for the nucleon electric plus magnetic polarizability $\Sigma=\alpha+\beta$ and for the nucleon spin-polarizability $\gamma$, to virtual photons with $Q^2>0$. The dominant low energy cross sections are…
The ratio of the proton form factors, GEp/GMp, has been measured from Q2 of 0.5 GeV2 to 8.5 GeV2, at the Jefferson Laboratory, using the polarization transfer method. This ratio is extracted directly from the measured ratio of the…
The small fraction of the quark polarization of the nucleon obtained in deep inelastic lepton scattering is a consequence of a wrong assumption on the flux of polarized virtual photons in the analysis of the data. The true flux of polarized…
The inclusive double-spin asymmetry, A_1^p, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7…
The forward Compton scattering off the proton is determined by substituting the empirical total photoabsorption cross sections into dispersive sum rules. In addition to the spin-independent amplitude evaluated previously [Phys. Rev. D 92,…
The experimental status of the spin-dependent structure functions as obtained from the deep inelastic scattering experiments at CERN, SLAC, and DESY is reviewed. All data show a violation of the Ellis-Jaffe sum rule. The Bjorken sum rule is…
The strangeness contribution to the vector and axial form factors of the proton is presented for momentum transfers in the range 0.45 < $Q^2$ < 1.0 GeV$^2$. The results are obtained via a combined analysis of forward-scattering…
We study the polarized Bjorken sum rule at low momentum transfers in the range $0.22<Q<1.73 {\rm GeV}$ with the four-loop N$^3$LO expression for the coefficient function $C_{\rm Bj}(\alpha_s)$ in the framework of the common QCD perturbation…
We derive a new twist-3 partonic sum rule for the transverse spin of the proton, which involves the well-know quark spin structure function $g_T(x)=g_1(x)+g_2(x)$, the less-studied but known transverse gluon polarization density $\Delta…
The strong interaction is not well understood at low energy, or for interactions with low momentum transfer $Q^2$, but one of the clearest insights we have comes from Chiral Perturbation Theory ($\chi$PT). This effective treatment gives…
We present a NLO perturbative analysis of all available data on the polarized structure function g_1(x,Q^2) with the aim of making a quantitative test of the validity of the Bjorken sum rule, of measuring \alpha_s, and of deriving helicity…