141 research outputs found

    Confinement and short distance physics

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    We consider non-perturbative effects at short distances in theories with confinement. The analysis is straightforward within the Abelian models in which the confinement arises on classical level. In all cases considered (compact U(1) in 3D and 4D, dual Abelian Higgs model) there are non-perturbative contributions associated with short distances which are due to topological defects. In QCD case, both classical and quantum effects determine the role of the topological defects and the theoretical analysis has not been completed so far. Generically, the topological defects would result in 1/Q^2 corrections going beyond the standard Operator Product Expansion. We review existing data on the power corrections and find that the data favor existence of the novel corrections, at least at the mass scale of (1-2) GeV. We indicate crucial experiments which could further clarify the situation on the phenomenological side.Comment: 11 pp., Latex2e, 4 figures, epsfig.sty. Accepted for publication in Physics Letters

    Alfven Wave Generation by means of High Orbital Injection of Barium Cloud in Magnetosphere

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    An analysis of the Alfven wave generation associated with the barium vapor release at altitudes ~ 5.2 Earth's radii (ER) in the magnetosphere is presented. Such injections were executed in G-8 and G-10 experiments of the Combined Radiation and Radiation Effects Satellite (CRRES) mission. It is shown that the generation of Alfven waves is possible during the total time of plasma expansion. The maximum intensity of these waves corresponds to the time of complete retardation of the diamagnetic cavity created by the expansion of plasma cloud. The Alfven wave exhibits a form of an impulse with an effective frequency ~ 0.03-0.05 Hz. Due to the background conditions and wave frequency, the wave mainly oscillates along the geomagnetic field between the mirror reflection points situated at ~ 0.7 ER. The wave amplitude is sufficient to the generation of plasma instabilities and longitudinal electric field, and to an increase in the longitudinal energy of electrons to ~ 1 keV. These processes are the most probable for altitudes ~ 1 ER. The auroral kilometric radiation (AKR) at frequencies ~ 100 kHz is associated with these accelerated electrons. The acceleration of electrons and AKR can be observed almost continuously during the first minute and then from time to time with pauses about 35-40 s till 6-8 min after the release. The betatron acceleration of electrons at the recovery of the geomagnetic field is also discussed. This mechanism could be responsible for the acceleration of electrons resulting in the aurorae and ultra short radio wave storm at frequencies 50-300 MHz observed at the 8-10th min after the release.Comment: Presented at COSPAR 200

    Chiral symmetry breaking in confining theories and asymptotic limits of operator product expansion

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    The pattern of spontaneous chiral symmetry breaking (CSB) in confining background fields is analyzed. It is explicitly demonstrated how to get the inverse square root large proper time asymptotic of the operator product expansion which is needed for CSB.Comment: LaTeX, 20 pages; minor revision

    Monopole clusters at short and large distances

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    We present measurements of various geometrical characteristics of monopole clusters in SU(2) lattice gauge theory. The maximal Abelian projection is employed and both infinite, or percolating cluster and finite clusters are considered. In particular, we observe scaling for average length of segments of the percolating cluster between self-crossings, correlators of vacuum monopole currents, angular correlation between links along trajectories. Short clusters are random walks and their spectrum in length corresponds to free particles. At the hadronic scale, on the other hand, the monopole trajectories are no longer random walks. Moreover, we argue that the data on the density of finite clusters suggest that there are long-range correlations between finite clusters which can be understood as association of the clusters with two-dimensional surfaces, whose area scales.Comment: 9 pages, 11 figure

    Study of the process of thermal dissociation of tantal pentachloride in vacuum

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    The dependence of the degree of dissociation of TaCl₅α(T, P) vapors on the temperature in the range of 1470...1820 K in a vacuum of 1.33·10⁻² Pa was by using of equilibrium chemical thermodynamics obtained. The experimental data on the dependence of αex(Т, Р) on temperature and vapor mass flow TaCl₅ were analyzed and compared with calculations.У рамках рівноважної хімічної термодинаміки отримана залежність ступеня дисоціації парів TaCl₅α(T, P) від температури в інтервалі 1470…1820 К і вакуумі 1,33·10⁻² Па. Проаналізовано та порівняно з розрахунковими експериментальні дані залежності αексп(Т, Р) від температури і масового потоку парів TaCl₅.В рамках равновесной химической термодинамики получена зависимость степени диссоциации паров TaCl₅α(T, P) от температуры в интервале 1470…1820 К и вакууме 1,33·10⁻² Па. Проанализированы и сравниваются расчетные данные с экспериментальными данными зависимости αэксп(Т, Р) от температуры и массового потока паров TaCl₅

    Anatomy of the lattice magnetic monopoles

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    We study the Abelian and non-Abelian action densitynear the monopole in the maximal Abelian gauge of SU(2) lattice gauge theory. We find that the non-Abelian action density near the monopoles belonging to the percolating cluster decreases when we approach the monopole center. Our estimate of the monopole radius is R_mon ~ 0.04 fm.Comment: 9 pp., Latex2e, 2 figure (epsfig), published versio

    Towards understanding structure of the monopole clusters

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    We consider geometrical characteristics of monopole clusters of the lattice SU(2) gluodynamics. We argue that the polymer approach to the field theory is an adequate means to describe the monopole clusters. Both finite-size and the infinite, or percolating clusters are considered. We find out that the percolation theory allows to reproduce the observed distribution of the finite-size clusters in their length and radius. Geometrical characteristics of the percolating cluster reflect, in turn, the basic properties of the ground state of a system with a gap.Comment: 20 pages, RevTeX

    Dirac Strings and Monopoles in the Continuum Limit of SU(2) Lattice Gauge Theory

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    Magnetic monopoles are known to emerge as leading non-perturbative fluctuations in the lattice version of non-Abelian gauge theories in some gauges. In terms of the Dirac quantization condition, these monopoles have magnetic charge |Q_M|=2. Also, magnetic monopoles with |Q_M|=1 can be introduced on the lattice via the 't Hooft loop operator. We consider the |Q_M|=1,2 monopoles in the continuum limit of the lattice gauge theories. To substitute for the Dirac strings which cost no action on the lattice, we allow for singular gauge potentials which are absent in the standard continuum version. Once the Dirac strings are allowed, it turns possible to find a solution with zero action for a monopole--antimonopole pair. This implies equivalence of the standard and modified continuum versions in perturbation theory. To imitate the nonperturbative vacuum, we introduce then a nonsingular background. The modified continuum version of the gluodynamics allows in this case for monopoles with finite non-vanishing action. Using similar techniques, we construct the 't Hooft loop operator in the continuum and predict its behavior at small and large distances both at zero and high temperatures.Comment: 24 pp., Latex2e, no figures. Minor correction

    Search for light pseudoscalar sgoldstino in K- decays

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    A search for the light pseudoscalar sgoldstino production in the three body K- decay K-->pipi0P has been performed with the ISTRA+ detector exposed to the 25 GeV negative secondary beam of the U70 proton synchrotron. No signal is seen. An upper limit for the branching ratio Br(K->pipi0P), at 90% confidence level, is found to be around 9*10**-6 in the effective mass m(P) range from 0 till 200 MeV, excluding the region near m(pi0) where it degrades to 3.5*10**-5.Comment: 10 pages, LATEX, 8 EPS figures, revised version, to be published in Phys.Lett.
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