3,098 research outputs found
Squeezed correlations of strange particle-antiparticles
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
Options for the SELEX state D_{s\J}^+(2632)
We consider possible assignments for the D_{s\J}^+(2632), which was
recently reported in D and DK final states by the SELEX
Collaboration at Fermilab. The most plausible quark model assignment for this
state is the first radial excitation () of the
D, although the predicted mass and strong decay branching fractions
for this assignment are not in agreement with the SELEX data. The reported
dominance of D over DK appears especially problematic. An intriguing
similarity to the K is noted. --^3\D_1 configuration
mixing is also considered, and we find that this effect is unlikely to resolve
the branching fraction discrepancy. Other interpretations as a -hybrid
or a two-meson molecule are also considered, but appear unlikely. Thus, if this
state is confirmed, it will require reconsideration of the systematics of
charmed meson spectroscopy and strong decays.Comment: 6 revtex4 pages, 2 eps figure
Representations of -semigroups by multiplace functions
We describe the representations of -semigroups, i.e. groupoids with
binary associative operations, by partial -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
The Shears Mechanism in 142Gd in the Skyrme-Hartree-Fock Method with the Tilted-Axis Cranking
We report on the first Skyrme-Hartree-Fock calculations with the tilted-axis
cranking in the context of magnetic rotation. The mean field symmetries,
differences between phenomenological and self-consistent methods and the
generation of shears-like structures in the mean field are discussed.
Significant role of the time-odd spin-spin effective interaction is pointed
out. We reproduce the shears mechanism, but quantitative agreement with
experiment is rather poor. It may have to do with too large core polarization,
lack of pairing correlations or properties of the Skyrme force.Comment: Presented at the XXVII Mazurian Lakes School of Physics, September
2-9 2001, Krzyze, Poland, Submitted to Acta Physica Polonic
Pentaquark implications for exotic mesons
If the exotic baryon is a correlated with , then there should exist an exotic meson, GeV with width MeV. The
may be broad members of {\bf 10} \10bar in such a
picture. Vector mesons in the 1.4 - 1.7GeV mass range are also compared with
this picture
Representations of Menger -semigroups by multiplace functions
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
-place functions is an -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 -place functions, which have many important applications for the
study of binary and -ary operations. We present methods of representations
of such algebras by -place functions and find an abstract characterization
of the set of -place functions closed with respect to the set-theoretic
inclusion
Squeezed K^+ K^- correlations in high energy heavy ion collisions
The hot and dense medium formed in high energy heavy ion collisions may
modify some hadronic properties. In particular, if hadron masses are shifted
in-medium, it was demonstrated that this could lead to back-to-back squeezed
correlations (BBC) of particle-antiparticle pairs. Although well-established
theoretically, the squeezed correlations have not yet been discovered
experimentally. A method has been suggested for the empirical search of this
effect, which was previously illustrated for phi-phi pairs. We apply here the
formalism and the suggested method to the case of K^+ K^- pairs, since they may
be easier to identify experimentally. The time distribution of the emission
process plays a crucial role in the survival of the BBC's. We analyze the cases
where the emission is supposed to occur suddenly or via a Lorentzian
distribution, and compare with the case of a Levy distribution in time. Effects
of squeezing on the correlation function of identical particles are also
analyzed.Comment: 9 pages and 6 figures (figures 2 to 6 contain 4 plots each).
Paragraph added to text, figures 2 to 6 revised for improving visualizatio
Tetrahedral Symmetry in Ground- and Low-Lying States of Exotic A ~ 110 Nuclei
Recent theoretical calculations predict a possible existence of nuclei with
tetrahedral symmetry: more precisely, the mean-field hamiltonians of such
nuclei are symmetric with respect to double point-group Td. In this paper, we
focus on the neutron-rich Zirconium isotopes as an example and present
realistic mean-field calculations which predict tetrahedral ground-state
configurations in 108,110Zr and low-lying excited states of tetrahedral
symmetry in a number of N > 66 isotopes. The motivations for focusing on these
nuclei, as well as a discussion of the possible experimental signatures of
tetrahedral symmetry are also presented.Comment: Accepted in Phys. Rev. C - Rapid Communication
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