218 research outputs found
Next-to-next-to-leading order fits to CCFR'97 data and infrared renormalons
We briefly summarize the outcomes of our recent improved fits to the
experimental data of CCFR collaboration for structure function of deep-inelastic scattering at the next-to-next-to-leading order. Special
attention is paid to the extraction of and the parameter of the
infrared renormalon model for -correction at different orders of
perturbation theory. The results can be of interest for planning similar
studies using possible future data of Neutrino Factories.Comment: 3 pages, presented at WG3 of 4th NuFact'02 Workshop, London 1-6 July,
200
Manifestation of New Interference Effects in Superconductor/Ferromagnet Spin Valve
Superconductor/ferromagnet (S/F) spin valve effect theories based on the S/F
proximity phenomenon assume that the superconducting transition temperature Tc
of F1/F2/S or F1/S/F2 trilayers for parallel magnetizations of the F1- and
F2-layers (TcP) are smaller than for the antiparallel orientations (TcAP).
Here, we report for CoOx/Fe1/Cu/Fe2/In multilayered systems with varying
Fe2-layer thickness the sign-changing oscillating behavior of the spin valve
effect \Delta Tc=TcAP-TcP. Our measurements revealed the full direct spin valve
effect with TcAP>TcP for Fe2-layer thickness dFe2<1 nm and the full inverse
(TcAP=1 nm. Interference of Cooper pair wave
functions reflected from both surfaces of the Fe2-layer appear as the most
probable reason for the observed behavior of \Delta Tc.Comment: Accepted for publication in PR
Various versions of analytic QCD and skeleton-motivated evaluation of observables
We present skeleton-motivated evaluation of QCD observables. The approach can
be applied in analytic versions of QCD in certain classes of renormalization
schemes. We present two versions of analytic QCD which can be regarded as
low-energy modifications of the ``minimal'' analytic QCD and which reproduce
the measured value of the semihadronic tau decay ratio r{tau}. Further, we
describe an approach of calculating the higher order analytic couplings Ak
(k=2,3,...) on the basis of logarithmic derivatives of the analytic coupling
A1(Q^2). This approach can be easily applied in any version of analytic QCD. We
adjust the free parameters of the afore-mentioned two analytic models in such a
way that the skeleton-motivated evaluation reproduces the correct known values
of r{tau} and of the Bjorken polarized sum rule (BjPSR) db(Q^2) at a given
point (e.g., at Q^2=2 GeV^2). We then evaluate the low-energy behavior of the
Adler function dv(Q^2) and the BjPSR db(Q^2) in the afore-mentioned evaluation
approach, in the three analytic versions of QCD. We compare with the results
obtained in the ``minimal'' analytic QCD and with the evaluation approach of
Milton et al. and Shirkov.Comment: 30 pages, 14 eps-figures; v3: parameters of the analytic QCD models
M1 and M2 were refined, the numerical results modified accordingly, new
paragraph at the end of Sec.II and at the end of Sec.III, discussion of
Figs.4 extended, references added; version to appear in PR
Full spin switch effect for the superconducting current in a superconductor/ferromagnet thin film heterostructure
Superconductor/ferromagnet (S/F) proximity effect theory predicts that the
superconducting critical temperature of the F1/F2/S or F1/S/F2 trilayers for
the parallel orientation of the F1 and F2 magnetizations is smaller than for
the antiparallel one. This suggests a possibility of a controlled switching
between the superconducting and normal states in the S layer. Here, using the
spin switch design F1/F2/S theoretically proposed by Oh et al. [Appl. Phys.
Lett. 71, 2376 (1997)], that comprises a ferromagnetic bilayer separated by a
non-magnetic metallic spacer layer as a ferromagnetic component, and an
ordinary superconductor as the second interface component, we have successfully
realized a full spin switch effect for the superconducting current.Comment: 5 pages, 4 figure
The analytical singlet QCD contributions into the -annihilation Adler function and the generalized Crewther relations
The generalized Crewther relations in the channels of the non-singlet and
vector quark currents are considered. They follow from the double application
of the operator product expansion approach to the same axial
vector-vector-vector triangle amplitude in two regions, adjoining to the angle
sides (or ). We assume that the generalized Crewther relations
in these two kinematic regimes result in the existence of the same perturbation
expression for two products of the coefficient functions of annihilation and
deep-inelastic scattering processes in the non-singlet and vector channels.
Taking into account the 4-th order result for and the perturbative
effects of the violation of the conformal symmetry in the generalized Crewther
relation, we obtain the analytical contribution to the singlet
correction to the -function. Its a-posteriori comparison with the
recent result of direct diagram-by-diagram evaluation of the singlet 4-th order
corrections to - function demonstrates the coincidence of the
predicted and obtained -contributions to the singlet term. They can
be obtained in the conformal invariant limit from the original Crewther
relation. On the contrary to previous belief, the appearance of -terms
in perturbative series in gauge models does not contradict to the property of
conformal symmetry and can be considered as ragular feature. The Banks-Zaks
motivated relation between our predicted and obtained 4-th order corrections is
mentioned. This confirms Baikov-Chetyrkin-Kuhn expectation that the generalized
Crewther relation in the channel of vector currents receives additional singlet
contribution, which in this order of perturbation theory is proportional to the
first coefficient of the QCD -function.Comment: Concrete new foundations explained, abstract updated, presentation
improved, 2 references added, extra acknowledgements added. This work is
dedicated to K. G. Chetyrkin on the occasion of his 60th anniversary, to be
published in Jetp. Lett supposedly in vol.94, issue 1
Infrared renormalons and analyticity structure in pQCD
Relation between the infrared renormalons, the Borel resummation
prescriptions, and the analyticity structure of Green functions in perturbative
QCD (pQCD) is investigated. A specific recently suggested Borel resummation
prescription resulted in the Principal Value and an additional power-suppressed
correction that is consistent with the Operator Product Expansion. Arguments
requiring the finiteness of the result for any power coefficient of the leading
infrared renormalon, and the consistency in the case of the absence of that
renormalon, require that this prescription be modified. The apparently most
natural modification leads to the result represented by the Principal Value.
The analytic structure of the amplitude in the complex coupling plane, obtained
in this way, is consistent with that obtained in the literature by other
methods.Comment: 6 pages, revtex4, 1 eps-figure; improved version - the paragraph
containing Eqs.(18) and (19) is new, as well as the next paragraph; the Title
modified; some references added; version to appear in Phys. Rev.
Analytic and "frozen" QCD coupling constants up to NNLO from DIS data
Deep inelastic scattering data on the F_2 structure function provided by the
BCDMS, SLAC and NMC collaborations are analyzed in the non-singlet
approximation with the analytic and "frozen" modifications of the strong
coupling constant featuring no unphysical singularity (the Landau pole).
Improvement of agreement between theory and experiment, with respect to the
case of the standard perturbative definition of alpha_s considered recently, is
observed and the behavior of the higher twist terms in the
next-to-next-to-leading-order is found to be confirming earlier studies on the
subject.Comment: 22 pp, 8 fig
Π€ΠΠΠΠΠ-Π₯ΠΠΠΠ§ΠΠ‘ΠΠΠ ΠΠΠΠΠΠΠΠΠ ΠΠΠ‘Π’Π ΠΠ ΠΠ¦ΠΠ‘Π‘Π ΠΠΠΠΠ’Π ΠΠΠΠ‘Π‘Π’ΠΠΠΠΠΠΠΠΠ― ΠΠΠ‘ΠΠΠ ΠΠΠ Π ΠΠ ΠΠ‘Π£Π’Π‘Π’ΠΠΠ ΠΠ ΠΠ ΠΠΠΠ«Π₯ ΠΠΠ’ΠΠΠΠ‘ΠΠΠΠΠ’ΠΠ
The effect of individual antioxidants on physico-chemical parameters of ORR was studied under conditions of liner semi-infinite diffusion. Rate constants for coupled homogeneous reduction of active oxygen by the range to flavonoids were calculated under the optimal linear sweep rate.Possibility of determination of the parameters of reduction of active oxygen process (chemical and electrochemical rate constant, reversibility of process) in addition of individual antioxidants was showed by the computer simulation. Identification of substances with antioxidant properties was illustrated by changing of reduction current of active oxygen.Keywords: oxygen reduction reaction, ORR, antioxidant, flavonoids, rate constant, voltammetry(Russian)DOI:Β http://dx.doi.org/10.15826/analitika.2013.17.4.007A.N. Vtorushina, E.I. Korotkova, S.G. Kataev*Β Tomsk Polytechnic University, Tomsk, Russian Federation*Tomsk State Pedagogical University, Tomsk, Russian FederationΠ Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΡΠΈΠ·ΠΈΠΊΠΎ-Ρ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π·Π°ΠΊΠΎΠ½ΠΎΠΌΠ΅ΡΠ½ΠΎΡΡΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ° ΡΠ»Π΅ΠΊΡΡΠΎΠ²ΠΎΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΡ ΠΊΠΈΡΠ»ΠΎΡΠΎΠ΄Π° (ΠΠΒ Π2) Π² ΠΏΡΠΈΡΡΡΡΡΠ²ΠΈΠΈ ΠΈΠ½Π΄ΠΈΠ²ΠΈΠ΄ΡΠ°Π»ΡΠ½ΡΡ
Π°Π½ΡΠΈΠΎΠΊΡΠΈΠ΄Π°Π½ΡΠΎΠ² Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ
Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΠΏΠΎΠ»ΡΠ±Π΅ΡΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠΉ Π΄ΠΈΡΡΡΠ·ΠΈΠΈ, ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΠΊΠΎΠ½ΡΡΠ°Π½ΡΡ ΡΠΊΠΎΡΠΎΡΡΠΈ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ Π°Π½ΡΠΈΠΎΠΊΡΠΈΠ΄Π°Π½ΡΠΎΠ² Ρ Π°ΠΊΡΠΈΠ²Π½ΡΠΌΠΈ ΡΠΎΡΠΌΠ°ΠΌΠΈ ΠΊΠΈΡΠ»ΠΎΡΠΎΠ΄Π° ΠΈ Π½Π΅ΠΊΠΎΡΠΎΡΡΠ΅ Π΄ΡΡΠ³ΠΈΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ ΠΏΡΠΎΡΠ΅ΡΡΠ° Π΄Π»Ρ ΡΡΠ΄Π° ΡΠ»Π°Π²ΠΎΠ½ΠΎΠΈΠ΄ΠΎΠ² ΠΏΡΠΈ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΊΠΎΡΠΎΡΡΠΈ ΡΠ°Π·Π²Π΅ΡΡΠΊΠΈ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»Π°. ΠΠΎΠΊΠ°Π·Π°Π½Π° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΏΡΠΎΡΠ΅ΡΡΠ° ΠΠΒ Π2 (ΠΊΠΎΠ½ΡΡΠ°Π½Ρ ΡΠΊΠΎΡΠΎΡΡΠΈ Ρ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΡ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅Π°ΠΊΡΠΈΠΈ, ΠΎΠ±ΡΠ°ΡΠΈΠΌΠΎΡΡΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ°) Π² ΠΏΡΠΈΡΡΡΡΡΠ²ΠΈΠΈ ΠΈΠ½Π΄ΠΈΠ²ΠΈΠ΄ΡΠ°Π»ΡΠ½ΡΡ
Π°Π½ΡΠΈΠΎΠΊΡΠΈΠ΄Π°Π½ΡΠΎΠ² Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ, Π° ΡΠ°ΠΊΠΆΠ΅ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΈΠ΄Π΅Π½ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ Π²Π΅ΡΠ΅ΡΡΠ², ΠΎΠ±Π»Π°Π΄Π°ΡΡΠΈΡ
Π°Π½ΡΠΈΠΎΠΊΡΠΈΠ΄Π°Π½ΡΠ½ΡΠΌΠΈ ΡΠ²ΠΎΠΉΡΡΠ²Π°ΠΌΠΈ, ΠΏΠΎ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΡΠΎΠΊΠ° ΠΠΒ Π2 Π² ΠΏΡΠΈΡΡΡΡΡΠ²ΠΈΠΈ ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ².ΠΠ»ΡΡΠ΅Π²ΡΠ΅ ΡΠ»ΠΎΠ²Π°: ΡΠ»Π΅ΠΊΡΡΠΎΠ²ΠΎΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΠ΅ ΠΊΠΈΡΠ»ΠΎΡΠΎΠ΄Π°, Π°Π½ΡΠΈΠΎΠΊΡΠΈΠ΄Π°Π½ΡΡ, Π²ΠΎΠ»ΡΡΠ°ΠΌΠΏΠ΅ΡΠΎΠΌΠ΅ΡΡΠΈΡDOI:Β http://dx.doi.org/10.15826/analitika.2013.17.4.00
Evidence for Triplet Superconductivity in a Superconductor-Ferromagnet Spin Valve
We have studied the dependence of the superconducting (SC) transition
temperature on the mutual orientation of magnetizations of Fe1 and Fe2 layers
in the spin valve system CoO_x/Fe1/Cu/Fe2/Pb. We find that this dependence is
nonmonotonic when passing from the parallel to the antiparallel case and
reveals a distinct minimum near the orthogonal configuration. The analysis of
the data in the framework of the SC triplet spin valve theory gives direct
evidence for the long-range triplet superconductivity arising due to
noncollinearity of the two magnetizations.Comment: 5 pages (including 4 EPS figures). Version 2: final version as
published in PR
The Contemporary Chemical Composition of the Lakes Waters at Zone of Juncture of the Ufimian Swell and Pre-Urals Foredeep
ΠΡΠΏΠΎΠ»Π½Π΅Π½Π° ΠΎΡΠ΅Π½ΠΊΠ° ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ³ΠΎ Π³ΠΈΠ΄ΡΠΎΡ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΠΎΠ·Π΅Ρ, ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½Π½ΡΡ
Π² ΠΠΈΡΠ΅ΡΡΡΠΊΠΎ-Π‘ΡΠΊΡΡΠ½ΡΠΊΠΎΠΌ ΠΊΠ°ΡΡΡΠΎΠ²ΠΎΠΌ ΡΠ°ΠΉΠΎΠ½Π΅ ΠΠ΅ΡΠΌΡΠΊΠΎΠ³ΠΎ ΠΊΡΠ°Ρ. Π Π°ΠΉΠΎΠ½ Π² Π³Π΅ΠΎΠ»ΠΎΠ³ΠΎ-ΡΡΡΡΠΊΡΡΡΠ½ΠΎΠΌ ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΈ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΠ΅Ρ ΡΠ·ΠΊΠΎΠΉ ΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠΉ Π·ΠΎΠ½Π΅ ΠΊΠ°ΡΠ±ΠΎΠ½Π°ΡΠΎΠ² Π£ΡΠΈΠΌΡΠΊΠΎΠ³ΠΎ Π²Π°Π»Π° (Π²ΠΎΡΡΠΎΡΠ½Π°Ρ ΠΎΠΊΡΠ°ΠΈΠ½Π° ΠΠΎΡΡΠΎΡΠ½ΠΎ-ΠΠ²ΡΠΎΠΏΠ΅ΠΉΡΠΊΠΎΠΉ ΠΏΠ»Π°ΡΡΠΎΡΠΌΡ) ΠΈ ΡΠ΅ΡΡΠΈΠ³Π΅Π½Π½ΡΡ
ΠΏΠΎΡΠΎΠ΄ Π·Π°ΠΏΠ°Π΄Π½ΠΎΠΉ ΠΎΠΊΡΠ°ΠΈΠ½Ρ ΠΡΠ΅Π΄ΡΡΠ°Π»ΡΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΠ³ΠΈΠ±Π°. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ Π΄ΠΎΠΏΠΎΠ»Π½ΠΈΡΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΡΠ°Π»ΡΠ½ΡΡ Π³ΠΈΠ΄ΡΠΎΡ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ ΡΡΠΎΠ³ΠΎ ΡΠ»ΠΎΠΆΠ½ΠΎΠ³ΠΎ ΠΏΠΎ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΎ-Π³ΠΈΠ΄ΡΠΎΠ³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΌΡ ΡΡΡΠΎΠ΅Π½ΠΈΡ ΡΠ°ΠΉΠΎΠ½Π°
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