Scaling violation in electroproduction at large ω'

The GVD predictions for scaling violation in electroproduction at ω'?5 are presented and agree with data. The effects of charm are included and found negligible in the ω′?q² domain of present experiments, but appreciable at higher ω' and (or)q².     

Scaling in deep inelastic pion electroproduction

An attempt is made to apply a light cone dominance technique to the deep inelastic electroproduction of pions. A scaling law is derived which is in agreement with preliminary data.     

Scaling violation in γγ scattering

An unorthodox model is examined which predicts that scaling violations in structure functions are related to properties of the photon vacuum polarization amplitude. The relationship is approximate, but very useful. It reproduces the leading QCD prediction in all cases, and allows, as for instance in γγ scattering, to fill up on what QCD cannot say by itself. There is a simple formula for the total γγ cross-section, valid for all values of the photon mass. Data frome ⁺ e^? annihilation can be fed into it to obtain a fit to the measured photon structure function. The PLUTO data are not all difficult to reproduce.     

Scaling violation in the pion structure function

TheQ ²-dependence of the pion structure function extracted from high transverse momentum π⁰ production cross sections is examined. We find, in thex→1 region, that this dependence can be parametrized by a power of (1?x) increasing as ln lnQ ². This is in agreement with the expectations of asymptotic freedom and also seen in the structure function extracted from dilepton production. It is not possible to fit all of theQ ²-dependence with a simple power law term.     

Parity violation in pion electroproduction and photoproduction with a proton target

Parity violation in pion electroproduction and photoproduction on a proton target is investigated as a possible means of elucidating the structure of the electronic and non-leptonic neutral weak currents. We calculate both parity-violating effects caused directly by Z-boson exchange, which contributes only to electron scattering, and those due to parity-violating electromagnetic and nuclear interactions. The asymmetry in electroproduction is of order 20^?5, whereas that in photoproduction is ～10^?7. The sensitivity to the parameter sin²θ_w is investigated; it is a maximum at backward electron scattering angles. In addition to the Born terms, contributions from the Δ(1232) resonance and the light vector mesons [?(776) and ω(782)] are included in the model. Fits to the observed π⁰ and π⁺ electroproduction and photoproduction cross sections indicate that the model accounts for the production data in the medium energy region.     

Scaling violation in quasielastic electron scattering

The scaling law in quasielastic electron scattering is broken due to exchange forces. The violation in the longitudinal response function is attributed to the central part of exchange forces, while in the transverse response the tensor part also leads to the breaking. The effects of one-boson exchange potentials are discussed.     

Recoil polarization for delta excitation in pion electroproduction

We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W = 1.23 GeV at Q(2) = 1.0 (GeV/c)(2), obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S(1+)/M(1+)) = -(6.84 +/- 0.15)% and Re (E(1+)/M(1+)) = -(2.91 +/- 0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and ll(pi) < or = 1 truncation.     

Scaling violation and shadowing corrections at HERA

We study the value of shadowing corrections (SC) in the HERA kinematic region in the Glauber–Mueller approach. Since the Glauber–Mueller approach was proven in perturbative quantum chromodynamics (QCD) in the double-logarithmic approximation (DLA), we develop the DLA approach for the deep inelastic structure function which takes into account the SC. Our estimates show small SC for in the HERA kinematic region while they turn out to be sizable for the gluon structure function. We compare our estimates with those for gluon distribution in leading order (LO) and next to leading order (NLO) in the DGLAP evolution equations. Received: 21 September 1998 /Published online: 14 January 1999     

Scaling in a dual model for single particle inclusive electroproduction

Single particle inclusive electroproduction is studied by means of dual resonance models for currents making use of Müller's theorem. Generalized scaling behaviour holds when the photon mass goes to infinity in the target fragmentation region. When the photon mass is kept fixed the two current vertex factorises and the distribution of fragments becomes independent of the mass value.     

Scaling violation and the inelasticity of very high energy proton-proton interactions

The pseudorapidity measurements at LHC, although in the central region only, allows us to perform preliminary tests of the multiparticle production extrapolation formula inspired by the analysis of recent cosmic ray data. Feynman scaling violation in the form proposed originally by Wdowczyk and Wolfendale in the 1970s has been applied to the Pierre Auger Observatory and the Hi-Res group measurements. The consistency of the average extensive air shower development with the hypothesis of protons being the primary particles, as indicated by anisotropy observations, was found for a smooth rise of the scaling violation parameter. We have shown that the longitudinal momenta of the produced particles determined inclusively as rapidity (pseudorapidity) distributions measured by LHC experiments follow the same universal high energy distribution scaled respectively. The high degree of Feynman scaling violation is confirmed. The decrease of the very high energy interaction inelasticity suggested by the cosmic ray data analysis is found to be consistent with LHC measurements up to 7 TeV.     

Analysis of the electroproduction structure functions in the lowQ 2 region,combining the vector meson dominance and the parton model with possible scaling violation

The nucleon structure functionF ₂ is constructed and analysed for low values ofQ ² using the generalised vector meson dominance representation with the largeQ ² spectral function calculated from the analytic continuation of the parton model structure function. Various parametrisations of the parton distributions are considered. Possible effects of the largeQ ² scaling violation on the lowQ ² part of the structure function are investigated. The magnitude of the total contribution given by this asymptotic part can be as high as 50% of the vector meson contribution in the low-Q ², low-χ region. The contribution of the valence quarks alone to the structure function at lowQ ² turns out to be at least as important as the corresponding non-Pomeron Regge-pole-like terms coming from the vector meson part. Increase of the structure function with ν coming from the increase of the quark sea in the limit of small χ implied by QCD turns out to be relatively weak at lowQ ². Predictions of the model are compared with available experimental data. The photoproduction cross section and the nuclear effects in the structure function are also briefly discussed.     

A polarization relation and the measurement of the longitudinal response in pseudoscalar meson electroproduction off the nucleon

For pseudoscalar meson electroproduction off the nucleon in parallel kinematics a relation between three polarization observables is derived. It is shown that, without Rosenbluth separation, a measurement of the longitudinal strength can be achieved through three different ways. They are discussed with preliminary MAMI data for the reaction in the energy range of the resonance. Received: 30 March 2000 / Accepted: 8 May 2000     

Bohr's complementarity relation and the violation of CP symmetry in the neutral kaon system

We test Bohr's complementary relation, for single and bipartite neutral kaons. They present a system that is oscillating, decaying and breaks the CP symmetry. We discuss the effect of the CP violation and moreover show that the quantity that complements the single partite information for bipartite kaons is an entanglement measure. Which is independent of CP violation, while nonlocality is sensitive to CP violation.     

Self-diffusion in sheared colloidal suspensions: violation of fluctuation-dissipation relation

Using memory-function formalism we show that in sheared colloidal suspensions the fluctuation-dissipation theorem for self-diffusion, i.e., Einstein's relation between self-diffusion and mobility tensors, is violated and propose a new way to measure this violation in Brownian dynamics simulations. We derive mode-coupling expressions for the tagged particle friction tensor and for an effective, shear-rate dependent temperature.     

Scaling and excitation of combined convection in a rapidly rotating plane layer

The optimum (to my mind) scaling of the combined thermal and compositional convection in a rapidly rotating plane layer is proposed.This scaling follows from self-consistent estimates of typical physical quantities. Similarity coefficients are introduced for the ratio convection dissipation/convection generation (s) and the ratio thermal convection/compositional convection (r). The third new and most important coefficient δ is the ratio of the characteristic size normal to the axis of rotation to the layer thickness. The faster the rotation, the lower δ. In the case of the liquid Earth core, δ ~ 10^–3 substitutes for the generally accepted Ekman number (E ~ 10^–15) and s ~ 10^–6 substitutes for the inverse Rayleigh number 1/Ra ~ 10^–30. It is found that, at turbulent transport coefficients, number s and the Prandtl number are on the order of unity for any objects and δ is independent of transport coefficients. As a result of expansion in powers of δ, an initially 3D system of six variables is simplified to an almost 2D system of four variables without δ. The problem of convection excitation in the main volume is algebraically solved and this problem for critical values is analytically solved. Dispersion relations and general expressions for critical wavenumbers, numbers s (which determine Rayleigh numbers), other critical parameters, and asymptotic solutions are derived. Numerical estimates are made for the liquid cores in the planets that resemble the Earth. Further possible applications of the results obtained are proposed for the interior of planets, moons, their oceans, stars, and experimental objects.     

Scaling laws and higher-order effects in Coulomb excitation of neutron halo nuclei

Essential properties of halo nuclei can be described in terms of a few low-energy constants. For neutron halo nuclei, analytical results can be found for wave functions and electromagnetic transition matrix elements in simple but well-adapted models. These wave functions can be used to study nuclear reactions; an especially simple and instructive example is Coulomb excitation. A systematic expansion in terms of small parameters can be given. We present scaling laws for excitation amplitudes and cross-sections. The results can be used to analyze experiments like ¹¹Be Coulomb excitation. They also serve as benchmark tests for more involved reaction theories.     

The relation between Hardy’s non-locality and violation of Bell inequality

We give an analytic quantitative relation between Hardy’s non-locality and Bell operator. We find that Hardy’s non-locality is a sufficient condition for the violation of Bell inequality, the upper bound of Hardy’s non-locality allowed by information causality just corresponds to Tsirelson bound of Bell inequality and the upper bound of Hardy’s non-locality allowed by the principle of no-signaling just corresponds to the algebraic maximum of Bell operator. Then we study the Cabello’s argument of Hardy’s non-locality (a generalization of Hardy’s argument) and find a similar relation between it and violation of Bell inequality. Finally, we give a simple derivation of the bound of Hardy’s non-locality under the constraint of information causality with the aid of the above derived relation between Hardy’s non-locality and Bell operator.