Study of correlation of production and decay planes in π→3π\pi\to3\pi diffractive dissociation process on nuclei

A large correlation of production and decay planes of (\pi^-\pi^+\pi^-)-system in dissociation of $\pi^-$-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.Comment: 8 pages, latex epsfig.sty, 5 eps figures. Submitted to Yad. Fiz

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 ($\pi^-\pi^+\pi^-$) triples from nuclei by the $40 GeV/c \pi^-$--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.Comment: 10 pp, 5 epsfig, Latex 2e, szjp.cls, epsfig.sty, wrapfig.sty included. Talk in "Spin and Symmetry - Praha98". To be published in Czechoslovak Journal of Physics, Supp

On the Spiral Structure of the Milky Way Galaxy

We consider the possible pattern of the overall spiral structure of the Galaxy, using data on the distribution of neutral (atomic), molecular, and ionized hydrogen, on the base of the hypothesis of the spiral structure being symmetric, i.e. the assumption that spiral arms are translated into each other for a rotation around the galactic center by 180{\deg} (a two-arm pattern) or by 90{\deg} (a four-arm pattern). We demonstrate that, for the inner region, the observations are best represented with a four-arm scheme of the spiral pattern, associated with all-Galaxy spiral density waves. The basic position is that of the Carina arm, reliably determined from distances to HII regions and from HI and H2 radial velocities. This pattern is continued in the quadrants III and IV with weak outer HI arms; from their morphology, the Galaxy should be considered an asymmetric multi-arm spiral. The kneed shape of the outer arms that consist of straight segments can indicate that these arms are transient formations that appeared due to a gravitational instability in the gas disk. The distances between HI superclouds in the two arms that are the brightest in neutral hydrogen, the Carina arm and the Cygnus (Outer) arm, concentrate to two values, permitting to assume the presence of a regular magnetic field in these arms.Comment: 21 pages, 14 fugures; accepted for publication in Astronomichesky Journal (Astron. Rep.

Factorization and infrared properties of non-perturbative contributions to DIS structure functions

In this paper we present a new derivation of the QCD factorization. We deduce the k_T- and collinear factorizations for the DIS structure functions by consecutive reductions of a more general theoretical construction. We begin by studying the amplitude of the forward Compton scattering off a hadron target, representing this amplitude as a set of convolutions of two blobs connected by the simplest, two-parton intermediate states. Each blob in the convolutions can contain both the perturbative and non-perturbative contributions. We formulate conditions for separating the perturbative and non-perturbative contributions and attributing them to the different blobs. After that the convolutions correspond to the QCD factorization. Then we reduce this totally unintegrated (basic) factorization first to the k_T- factorization and finally to the collinear factorization. In order to yield a finite expression for the Compton amplitude, the integration over the loop momentum in the basic factorization must be free of both ultraviolet and infrared singularities. This obvious mathematical requirement leads to theoretical restrictions on the non-perturbative contributions (parton distributions) to the Compton amplitude and the DIS structure functions related to the Compton amplitude through the Optical theorem. In particular, our analysis excludes the use of the singular factors x^{-a} (with a > 0) in the fits for the quark and gluon distributions because such factors contradict to the integrability of the basic convolutions for the Compton amplitude. This restriction is valid for all DIS structure functions in the framework of both the k_T- factorization and the collinear factorization if we attribute the perturbative contributions only to the upper blob.Comment: 19 pages, 6 figure

The Spin Content of the Nucleon

The fraction of the nucleon spin that is carried by the quarks, $\Delta \Sigma$, is computed in lattice QCD with dynamical staggered fermions. We obtain the value $\Delta \Sigma = 0.18 \pm 0.02$.Comment: (contribution to Lattice 1992), 4 pages + 1 encapsulated postscript figure, HLRZ 92-81 (In the earlier version the topological charge density was incorrectly normalized. ERRARE HUMANUM EST!

The gluon content of the η\eta and η′\eta^{\prime} mesons and the ηγ\eta\gamma, η′γ\eta^{\prime}\gamma electromagnetic transition form factors

We compute power-suppressed corrections to the \eta\gamma and \eta^{\prime}\gamma transition form factors Q^2F_{\eta(\eta^{\prime})\gamma}(Q^2) arising from the end point regions x \to 0,1 by employing the infrared-renormalon approach. The contribution to the form factors from the quark and gluon content of the \eta,\eta^{\prime} mesons is taken into account using for the \eta-\eta^{\prime} mixing the SU_f(3) singlet \eta_1 and octet \eta_8 basis. The theoretical predictions obtained this way are compared with the corresponding CLEO data and restrictions on the input parameters (Gegenbauer coefficients) B_2^q(\eta_1), B_2^g(\eta_1), and B_2^q(\eta_8) in the distribution amplitudes for the \eta_1,\eta_8 states with one nonasymptotic term are deduced. Comparison is made with the results from QCD perturbation theory.Comment: 25 pages, RevTeX4 used. 9 figures as EPS files. Text significantly changed to include variation of theoretical parameters. Figures modified. Corrected typo in equation (34) and trivial mistake in $\beta_1$-coefficient. References added. Conclusions unchange

Diffusion-controlled generation of a proton-motive force across a biomembrane

Respiration in bacteria involves a sequence of energetically-coupled electron and proton transfers creating an electrochemical gradient of protons (a proton-motive force) across the inner bacterial membrane. With a simple kinetic model we analyze a redox loop mechanism of proton-motive force generation mediated by a molecular shuttle diffusing inside the membrane. This model, which includes six electron-binding and two proton-binding sites, reflects the main features of nitrate respiration in E. coli bacteria. We describe the time evolution of the proton translocation process. We find that the electron-proton electrostatic coupling on the shuttle plays a significant role in the process of energy conversion between electron and proton components. We determine the conditions where the redox loop mechanism is able to translocate protons against the transmembrane voltage gradient above 200 mV with a thermodynamic efficiency of about 37%, in the physiologically important range of temperatures from 250 to 350 K.Comment: 26 pages, 4 figures. A similar model is used in arXiv:0806.3233 for a different biological system. Minor changes in the Acknowledgements sectio