A. V. Efremov — Page 5

arXiv1999

On the T-Odd Quark Fragmentation Function and on Transversal Handedness

The first probe of the correlation of the T-odd one-particle fragmentation function responsible for the left--right asymmetry of fragmentation of a transversely polarized quark is done by using the 1991-95 DELPHI data for $Z\to 2$-jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 1.5% order, which means order of 13% for the analyzing power. A rather large ($\approx 10%$) handedness transversal to the production plane was observed in the diffractive production of ($π^-π^+π^-$) triples from nuclei by the $40 GeV/c π^-$--beam. It was shown that the phenomenon has a clear dynamic origin and resembles the single spin asymmetry behavior. All this makes us hope to use this effects in polarized DIS experiments for transversity measurement.

hep-ph↗

arXiv1999

Study of correlation of production and decay planes in $π\to3π$ diffractive dissociation process on nuclei

A large correlation of production and decay planes of (π^-π^+π^-)-system in dissociation of $π^-$-beam 40 GeV/c on nuclear targets was observed. The dependence of the correlation on atomic number, Feynmann variable and transversal momentum as well as on invariant mass of the pion triple and neutral pion pair were investigated. It was shown that the phenomenon has a clear dynamic origin and resembles the single spin asymmetry behavior.

nucl-th↗

arXiv1998

Study of T-odd Quark Fragmentation Function in $Z^0\to 2$-jet Decay

The first probe of the correlation of the T-odd one-particle fragmentation function responsible for the left--right asymmetry of fragmentation of a transversely polarized quark and an antiquark is done by using the 1991-95 DELPHI data for $Z\to 2$ jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 2.5 ppm order, which means order of 7% for the analyzing power. This makes us hope to use certain effects in polarized DIS experiments for transversity measurement.

hep-ph↗

arXiv1997

Nuclear Structure Functions and Cumulative Processes

The authors's point of view, based on QCD, on the nuclear quark structure is presented. Different models for explaining the EMC--effect are considered. It is also shown that cumulative production data are very useful for a better understanding of the EMC--effect and give some evidence in favor of its multiquark nature.

hep-ph↗

arXiv1996

An exact sum rule for transversely polarized DIS

The Operator Product Expansion provides expressions for the $n^{th}$ moments of $g_1(x)$ and $g_2(x)$ in terms of hadronic matrix elements of local operators for $n =$ odd integer. In some cases these matrix elements are expected to be small leading to approximate sum rules for the {\em odd\/} moments of $g_{1,2}(x)$. We have shown how, working in a field-theoretic framework, one can derive expressions for the {\em even\/} moments of the {\em valence\/} parts of $g_{1,2}(x)$. These expressions cannot be written as matrix elements of {\em local\/} operators and do not coincide with the analytic continuation to $n=$ even integer of the OPE results. Just as for the OPE one can in some cases argue that the hadronic matrix elements should be small, leading to approximate sum rules for the moments of the valence parts of $g_{1,2}(x)$. But, most importantly, for the case $n=2$ we have proved rigorously that the hadronic matrix element vanishes, yielding the exact ELT sum rule \int^1_0 dx\, x\left[g^V_1(x)+2g^V_2(x)\right]=0. We have argued that the convergence properties of this sum rule are good and have discussed how it can be used to get information about $g_2(x)$ and as a further test of QCD.

hep-ph↗

arXiv1995

Gluon Contribution to the Transverse Spin Structure Function g2

We consider the twist-3 gluon contribution to the transverse spin structure function $g_2$.We find that the Burkhardt-Cottingham sum rule is satisfied. The additional {\it nonlocal} operators appear in the moments of g2 which were absent in previous analysis of Bukhvostov, Kuraev and Lipatov.

hep-ph↗