Improvement in braking devices on Pilger mills

Calculation of chirality-violating proton structure functionh1(x) in QCD

“…Let the momenta, corresponding to the currents η(x) and j(x) be p and q. As was shown in [5,6], the imaginary part of the forward scattering amplitude is determined by small distances in t-channel if p 2 and q 2 are negative and large enough, | p 2 |, | q 2 |≫ R −2 , (R is the confinement radius) and the Bjorken scaling variable x = Q 2 /2ν, Q 2 = −q 2 , ν = p · q is not close to the boundary values x = 0 and x = 1. Therefore, to calculate the amplitude of interest we may use the operator product expansion (OPE) method accounting the vacuum expectation values (v.e.v.)…”

“…In this paper we calculate the proton structure function h p 1 (x) by means of the QCD sum rule approach. The idea of the method is the following [5,6]. Consider the four-point vacuum correlator corresponding to the amplitude of forward scattering of the current η(x) with proton quantum numbers on external currents j 1 (x), j 2 (x).…”

“…Consider the four-point vacuum correlator corresponding to the amplitude of forward scattering of the current η(x) with proton quantum numbers on external currents j 1 (x), j 2 (x). (In the case of the structure function F 2 (x) considered earlier [5,6] j 1 (x), j 2 (x) were electromagnetic or weak currents). Let the momenta, corresponding to the currents η(x) and j(x) be p and q.…”

Distribution of valence quarks and light-cone QCD sum rules

“…In ref. [8], Ioffe proposed a four-point correlator for theoretical calculations of quark distribution functions in the QCD sum rule approach suggested by Shifman, Vainshtein and Zakharov [9]. This method was applied for calculations of nucleon structure functions, such as F 2 (x B ) [10], g 1 (x B ) and g 2 (x B ) [11], h 1 (x B ) [12].…”

“…Recently, it was suggested to apply this version of QCD sum rules to the problem of calculating the deep-inelastic structure function [14]. This light-cone QCD sum rule is based on the fact (which was noted by Ioffe in [8]) that if x B is not close to the boundary x B = 0 and x B = 1, then the imaginary part of the deep-inelastic scattering amplitude is determined by small distances in the t-channel. In the case of the pion structure function, the nearest singularity in the t-channel for the correlator of two vector currents and one axial current with a pion in the initial state is at t = − x B 1−x B p 2 for highly virtual photons, where p is a momentum of the axial current.…”