749 research outputs found
Graded polynomial identities, group actions, and exponential growth of Lie algebras
Consider a finite dimensional Lie algebra L with an action of a finite group
G over a field of characteristic 0. We prove the analog of Amitsur's conjecture
on asymptotic behavior for codimensions of polynomial G-identities of L. As a
consequence, we prove the analog of Amitsur's conjecture for graded
codimensions of any finite dimensional Lie algebra graded by a finite Abelian
group.Comment: 26 pages; minor misprints were correcte
Measurement of (1020) meson leptonic width with CMD-2 detector at VEPP-2M Collider
The (1020) meson leptonic width has been determined from the combined
analysis of 4 major decay modes of the resonance () studied with the CMD-2 detector at
the VEPP-2M collider. The following value has been obtained:
keV.
The meson parameters in four main decay channels have been also
recalculated: , , , .Comment: 14 pages, 3 figure
Global well-posedness for the KP-I equation on the background of a non localized solution
We prove that the Cauchy problem for the KP-I equation is globally well-posed
for initial data which are localized perturbations (of arbitrary size) of a
non-localized (i.e. not decaying in all directions) traveling wave solution
(e.g. the KdV line solitary wave or the Zaitsev solitary waves which are
localized in and periodic or conversely)
Proton linear accelerator for boron-neutron capture therapy
At the present time radiotherapy, surgery and chemotherapy are the main methods of treatment of malignant tumors. They may be used individually or in combination with other methods
High-statistics measurement of the pion form factor in the rho-meson energy range with the CMD-2 detector
We present a measurement of the pion form factor based on e+e- annihilation
data from the CMD-2 detector in the energy range 0.6<sqrt(s)<1.0 GeV with a
systematic uncertainty of 0.8%. A data sample is five times larger than that
used in our previous measurement.Comment: 18 pages, 10 figures. Added comparison with KLOE measurement, minor
updates. Accepted by PL
From nonassociativity to solutions of the KP hierarchy
A recently observed relation between 'weakly nonassociative' algebras A (for
which the associator (A,A^2,A) vanishes) and the KP hierarchy (with dependent
variable in the middle nucleus A' of A) is recalled. For any such algebra there
is a nonassociative hierarchy of ODEs, the solutions of which determine
solutions of the KP hierarchy. In a special case, and with A' a matrix algebra,
this becomes a matrix Riccati hierarchy which is easily solved. The matrix
solution then leads to solutions of the scalar KP hierarchy. We discuss some
classes of solutions obtained in this way.Comment: 7 pages, 4 figures, International Colloquium 'Integrable Systems and
Quantum Symmetries', Prague, 15-17 June 200
Study of the Process e+ e- --> omega pi0 --> pi0 pi0 gamma in c.m. Energy Range 920--1380 MeV at CMD-2
The cross section of the process e+ e- --> omega pi0 --> pi0 pi0 gamma has
been measured in the c.m. energy range 920-1380 MeV with the CMD-2 detector.
Its energy dependence is well described by the interference of the rho(770) and
rho'(1450) mesons decaying to omega pi0. Upper limits for the cross sections of
the direct processes e+ e- --> pi0 pi0 gamma, eta pi0 gamma have been set.Comment: Accepted for publication in PL
Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins
New formulation of relativistic wave equations (RWE) for massive particles
with arbitrary half-integer spins s interacting with external electromagnetic
fields are proposed. They are based on wave functions which are irreducible
tensors of rank n=s-\frac12$) antisymmetric w.r.t. n pairs of indices,
whose components are bispinors. The form of RWE is straightforward and free of
inconsistencies associated with the other approaches to equations describing
interacting higher spin particles
Research of the state of internal surfaces of a supercritical water loop after a session of irradiation
Made of austenitic steel at the NSC KIPT, the supercritical water convection loop Loop-1a was running for more than 500 hours in the first experimental session (in 2011). The materials tested in the loop were placed into a stream of water (more than 50 g/s) at a temperature of 350…400°C, a pressure of 23… 25 MPa, and were irradiated by an electron beam with an energy of 10 MeV. Sediments that emerged on the inner surface of the loop were examined. The sediment mainly consisted of compounds of calcium and iron mixed with other elements. There is a possibility to increase corrosion induced by radiation due to dislocation damage, hydrogenation of metal and under the impact of active oxygen.Виготовлена з аустенітної стали в ННЦ ХФТІ надкритична водяна конвекційна петля Loop-1a в першому експериментальному сеансі (2011 рік) пропрацювала понад 500 год. Випробовувані у петлі матеріали перебували в потоці води (понад 50 г/с) при температурі 350…400°C, тиску 23…25 МПа і опромінювалися електронним пучком енергією 10 МеВ. Досліджували відкладення на внутрішній поверхні петлі, які складаються в основному із сполук кальцію і заліза з домішкою інших елементів. Можливе посилення корозії під дією випромінювання за рахунок дислокаційних ушкоджень, насичення воднем і активного кисню.Изготовленная из аустенитной стали в ННЦ ХФТИ сверхкритическая водяная конвекционная петля Loop-1a в первом экспериментальном сеансе (2011 год) проработала более 500 ч. Испытываемые в петле материалы находились в потоке воды (более 50 г/с) при температуре 350…400°C, давлении 23… 25 МПа и облучались электронным пучком энергией 10 МэВ. Исследовали отложения на внутренней поверхности петли, которые состоят в основном из соединений кальция и железа с примесью других элементов. Возможно усиление коррозии под действием излучения за счет дислокационных повреждений, наводорoживания и активного кислорода
Study of the Process e+ e- --> pi0 pi0 gamma in c.m. Energy Range 600--970 MeV at CMD-2
The cross section of the process e+ e- --> pi0 pi0 gamma has been measured in
the c.m. energy range 600--970 MeV with the CMD-2 detector. The following
branching ratios have been determined: B(rho --> pi0 pi0 gamma)
=(5.2^{+1.5}_{-1.3} +- 0.6)x10^{-5} and B(omega --> pi0 pi0 gamma)
=(6.4^{+2.4}_{-2.0} +- 0.8)x10^{-5}. Evidence for the rho --> f0(600) gamma
decay has been obtained: B(rho --> f0(600) gamma) = (6.0^{+3.3}_{-2.7}\pm
0.9)x10^{-5}. From a search for the process e+ e- --> eta pi0 gamma the
following upper limit has been obtained: B(omega --> eta pi0 gamma) < 3.3
10^{-5} at 90% CL.Comment: 15 pages, 4 figure
- …