4,320 research outputs found

    Interaction Strengths for the Fock-Space Formulation of the Nuclear Pairing Problem

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    A realistic nuclear mean-field hamiltonian with pairing has been diagonalized using Fock space representation that allows for nearly exact treatment of the problem. Calculations were performed for all the even-even nuclei with Z in (20, 100), whose pairing gaps were possible to extract out of the experimental masses. The optimal values of the pairing strength constants for the protons and neutrons have been found.Comment: Seminar given at XXXVII School of Physics in Zakopane, Poland. Paper in LaTeX, 4 pages including one figure, submitted to Acta Physica Polonica

    Solid weak BCC-algebras

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    We characterize weak BCC-algebras in which the identity (xy)z=(xz)y(xy)z=(xz)y is satisfied only in the case when elements x,yx,y belong to the same branch

    Representations of (2,n)(2,n)-semigroups by multiplace functions

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    We describe the representations of (2,n)(2,n)-semigroups, i.e. groupoids with nn binary associative operations, by partial nn-place functions and prove that any such representation is a union of some family of representations induced by Schein's determining pairs.Comment: 17 page

    Characterizations of quasitrivial symmetric nondecreasing associative operations

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    We provide a description of the class of n-ary operations on an arbitrary chain that are quasitrivial, symmetric, nondecreasing, and associative. We also prove that associativity can be replaced with bisymmetry in the definition of this class. Finally we investigate the special situation where the chain is finite

    Squeezed correlations of strange particle-antiparticles

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    Squeezed correlations of hadron-antihadron pairs are predicted to appear if their masses are modified in the hot and dense medium formed in high energy heavy ion collisions. If discovered experimentally, they would be an unequivocal evidence of in-medium mass shift found by means of hadronic probes. We discuss a method proposed to search for this novel type of correlation, illustrating it by means of D_s-mesons with in-medium shifted masses. These particles are expected to be more easily detected and identified in future upgrades at RHIC.Comment: 6 pages, 3 figures with parts a) and b), SQM 2009 contribution; added acknowledgmen

    Representations of Menger (2,n)(2,n)-semigroups by multiplace functions

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    Investigation of partial multiplace functions by algebraic methods plays an important role in modern mathematics were we consider various operations on sets of functions, which are naturally defined. The basic operation for nn-place functions is an (n+1)(n+1)-ary superposition [][ ], but there are some other naturally defined operations, which are also worth of consideration. In this paper we consider binary Mann's compositions \op{1},...,\op{n} for partial nn-place functions, which have many important applications for the study of binary and nn-ary operations. We present methods of representations of such algebras by nn-place functions and find an abstract characterization of the set of nn-place functions closed with respect to the set-theoretic inclusion

    On fuzzy BCC-ideals over a t-norm

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    Using a t-norm T, the notion of T-fuzzy BCC-ideals of BCC-algebras is introduced, and some of their properties are investigated. Connections between different types of fuzzy BCC-ideals induced by t-norms are described

    Microscopic Study of Superdeformed Rotational Bands in 151Tb

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    Structure of eight superdeformed bands in the nucleus 151Tb is analyzed using the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is demonstrated that far going similarities between the two approaches exist and predictions related to the structure of rotational bands calculated within the two models are nearly parallel. An interpretation scenario for the structure of the superdeformed bands is presented and predictions related to the exit spins are made. Small but systematic discrepancies between experiment and theory, analyzed in terms of the dynamical moments, J(2), are shown to exist. The pairing correlations taken into account by using the particle-number-projection technique are shown to increase the disagreement. Sources of these systematic discrepancies are discussed -- they are most likely related to the yet not optimal parametrization of the nuclear interactions used.Comment: 32 RevTeX pages, 15 figures included, submitted to Physical Review

    Exotic and excited-state radiative transitions in charmonium from lattice QCD

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    We compute, for the first time using lattice QCD methods, radiative transition rates involving excited charmonium states, states of high spin and exotics. Utilizing a large basis of interpolating fields we are able to project out various excited state contributions to three-point correlators computed on quenched anisotropic lattices. In the first lattice QCD calculation of the exotic 1-+ eta_c1 radiative decay, we find a large partial width Gamma(eta_c1 -> J/psi gamma) ~ 100 keV. We find clear signals for electric dipole and magnetic quadrupole transition form factors in chi_c2 -> J/psi gamma, calculated for the first time in this framework, and study transitions involving excited psi and chi_c1,2 states. We calculate hindered magnetic dipole transition widths without the sensitivity to assumptions made in model studies and find statistically significant signals, including a non-exotic vector hybrid candidate Y_hyb? -> eta_c gamma. As well as comparison to experimental data, we discuss in some detail the phenomenology suggested by our results and the extent to which it mirrors that of quark potential models and make suggestions for the interpretation of our results involving exotic quantum numbered states
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