8,261 research outputs found

    Estimates for parameters and characteristics of the confining SU(3)-gluonic field in neutral kaons and chiral limit for pseudoscalar nonet

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    First part of the paper is devoted to applying the confinement mechanism proposed earlier by the author to estimate the possible parameters of the confining SU(3)-gluonic field in neutral kaons. The estimates obtained are consistent with the widths of the electromagnetic decays K0,Kˉ02γK^0,\bar{K}^0\to2\gamma too. The corresponding estimates of the gluon concentrations, electric and magnetic colour field strengths are also adduced for the mentioned field at the scales of the mesons under consideration. The second part of the paper takes into account the results obtained previously by the author to estimate the purely gluonic contribution to the masses of all the mesons of pseudoscalar nonet and also to consider a possible relation with a phenomenological string-like picture of confinement. Finally, the problem of masses in particle physics is shortly discussed within the framework of approach to the chiral symmetry breaking in quantum chromodynamics (QCD) proposed recently by the author.Comment: LaTeX, 16 pages, 2 figure

    Dirac Monopoles in the Ernst--Schwarzschild Spacetime

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    It is discussed that the Ernst--Schwarzschild metric describing a nonrotating black hole in the external magnetic field admits the solutions of the Dirac monopole types for the corresponding Maxwell equations. The given solutions are obtained in explicit form and a possible influence of the conforming Dirac monopoles on Hawking radiation is also outlined.Comment: Int. Journal of Modern Physics A, vol. 18 (2003), 2153-215

    Ions in glass forming glycerol: Close correlation of alpha and fast beta relaxation

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    We provide broadband dielectric loss spectra of glass-forming glycerol with varying additions of LiCl. The measurements covering frequencies up to 10 THz extend well into the region of the fast beta process, commonly ascribed to caged molecule dynamics. Aside of the known variation of the structural alpha relaxation time and a modification of the excess wing with ion content, we also find a clear influence on the shallow loss minimum arising from the fast beta relaxation. Within the framework of mode-coupling theory, the detected significant broadening of this minimum is in reasonable accord with the found variation of the alpha-relaxation dynamics. A correlation between alpha-relaxation rate and minimum position holds for all ion concentrations and temperatures, even below the critical temperature defined by mode-coupling theory.Comment: 5 pages, 5 figure

    Estimates for parameters and characteristics of the confining SU(3)-gluonic field in an η\eta^\prime-meson

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    The confinement mechanism proposed earlier by the author is applied to estimate the possible parameters of the confining SU(3)-gluonic field in an η\eta^\prime-meson. For this aim the electric form factor of an η\eta^\prime-meson is nonperturbatively computed in an explicit analytic form. The estimates obtained are also consistent with the width of the electromagnetic decay η2γ\eta^\prime\to2\gamma. The corresponding estimates of the gluon concentrations, electric and magnetic colour field strengths are also adduced for the mentioned field at the scales of the meson under consideration.Comment: 20 pages, LaTe

    Asymptotic normalization coefficients for mirror virtual nucleon decays in a microscopic cluster model

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    It has been suggested recently (Phys. Rev. Lett. 91, 232501 (2003)) that charge symmetry of nucleon-nucleon interactions relates the Asymptotic Normalization Coefficients (ANCs) of proton and neutron virtual decays of mirror nuclei. This relation is given by a simple analytical formula which involves proton and neutron separation energies, charges of residual nuclei and the range of their strong interaction with the last nucleon. Relation between mirror ANCs, if understood properly, can be used to predict astrophysically relevant direct proton capture cross sections using neutron ANCs measured with stable beams. In this work, we calculate one-nucleon ANCs for several light mirror pairs, using microscopic two-, three- and four-cluster models, and compare the ratio of mirror ANCs to the predictions of the simple analytic formula. We also investigate mirror symmetry between other characteristics of mirror one-nucleon overlap integrals, namely, spectroscopic factors and single-particle ANCs.Comment: 12 pages, submitted to Phys. Rev.

    Inflationary spacetimes are not past-complete

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    Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating -- or just expanding sufficiently fast -- must be incomplete in null and timelike past directions. Specifically, we obtain a bound on the integral of the Hubble parameter over a past-directed timelike or null geodesic. Thus inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.Comment: We improve the basic argument to apply to a wider class of spacetimes, use a better title and add a discussion of cyclic models. 4 pages, 1 figure, RevTe

    Benchmark on neutron capture extracted from (d,p)(d,p) reactions

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    Direct neutron capture reactions play an important role in nuclear astrophysics and applied physics. Since for most unstable short-lived nuclei it is not possible to measure the (n,γ)(n, \gamma) cross sections, (d,p)(d,p) reactions have been used as an alternative indirect tool. We analyze simultaneously 48Ca(d,p)49Ca^{48}{\rm Ca}(d,p)^{49}{\rm Ca} at deuteron energies 2,13,192, 13, 19 and 56 MeV and the thermal (n,γ)(n,\gamma) reaction at 25 meV. We include results for the ground state and the first excited state of 49^{49}Ca. From the low-energy (d,p)(d,p) reaction, the neutron asymptotic normalization coefficient (ANC) is determined. Using this ANC, we extract the spectroscopic factor (SF) from the higher energy (d,p)(d,p) data and the (n,γ)(n, \gamma) data. The SF obtained through the 56 MeV (d,p)(d,p) data are less accurate but consistent with those from the thermal capture. We show that to have a similar dependence on the single particle parameters as in the (n,γ)(n, \gamma), the (d,p) reaction should be measured at 30 MeV.Comment: 5 pg, 4 figs, Phys. Rev. C (rapid) in pres

    Inflationary cosmology of the extreme cosmic string

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    Starting with a study of the cosmological solution to the Einstein equations for the internal spacetime of an extreme supermassive cosmic string kink, and by evaluating the probability measure for the formation of such a kink in semiclassical approximation using a minisuperspace with the appropriate symmetry, we have found a set of arguments in favor of the claim that the kinked extreme string can actually be regarded as a unbounded chain of pairs of Planck- sized universes. Once one such universe pairs is created along a primordial phase transition at the Planck scale, it undergoes an endless process of continuous self-regeneration driven by chaotic inflation in each of the universes forming the pair.Comment: 15 pages, RevTex, to appear in Int. J. Mod. Phys.
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