16,381 research outputs found
The Charm of the Proton and the Production
We propose a two component model for charmed baryon production in
collisions consisting of the conventional parton fusion mechanism and
fragmentation plus quarks recombination in which a valence diquark from
the proton recombines with a -sea quark to produce a . Our
two-component model is compared with the intrinsic charm two-component model
and experimental data.Comment: 6 pages, LaTex, 2 figures included, aipproc.sty included. Talk
presented at Simposio Latino Americano de Fisica de Altas Energias, Merida,
Mexico, November 199
The Polarization and the Recombination Mechanism
We use the recombination and the Thomas Precession Model to obtain a
prediction for the polarization in the
reaction. We study the effect of the recombination function on the
polarization.Comment: 4 pages, LaTex, 1 figures included, aipproc.sty included. Talk
presented at Simposio Latino Americano de Fisica de Altas Energias, Merida,
Mexico, November 199
Hexaaquazinc(II) dinitrate bis[5-(pyridinium-3-yl)tetrazol-1-ide]
Indexación: Scopus.Funding for this research was provided by: Fondecyt Regular (award No. 1151527); Proyecto REDES ETAPA INICIAL, Convocatoria 2017 (award No. REDI170423); Millennium Institute for Research in Optics (MIRO); Basal USA (award No. 1799).Hexaaquazinc(II) dinitrate 5-(pyridinium-3-yl)tetrazol-1-ide, [Zn(H2 O)6](NO 3)2 ·2C6H5 N 5, crystallizes in the space group P. The asymmetric unit contains one zwitterionic 5-(pyridinium-3-yl)tetrazol-1-ide molecule, one NO3-anion and one half of a [Zn(H2 O)6]2+ cation (symmetry). The pyridinium and tetrazolide rings in the zwitterion are nearly coplanar, with a dihedral angle of 5.4 (2)°. Several O-H..N and N-H..O hydrogen-bonding interactions exist between the [Zn(H2 O)6]2+ cation and the N atoms of the tetrazolide ring, and between the nitrate anions and the N-H groups of the pyridinium ring, respectively, giving rise to a three-dimensional network. The 5-(pyridinium-3-yl)tetrazol-1-ide molecules show parallel-displaced π-π stacking interactions; the centroid-centroid distance between adjacent tetrazolide rings is 3.6298 (6) Å and that between the pyridinium and tetrazolide rings is 3.6120 (5) Å. © 2018 Chi-Duran et al.http://journals.iucr.org/e/issues/2018/09/00/cq2025/index.htm
Why does gravitational radiation produce vorticity?
We calculate the vorticity of world--lines of observers at rest in a
Bondi--Sachs frame, produced by gravitational radiation, in a general Sachs
metric. We claim that such an effect is related to the super--Poynting vector,
in a similar way as the existence of the electromagnetic Poynting vector is
related to the vorticity in stationary electrovacum spacetimes.Comment: 9 pages; to appear in Classical and Quantum Gravit
Key polynomials for simple extensions of valued fields
Let be a simple transcendental extension
of valued fields, where is equipped with a valuation of rank 1. That
is, we assume given a rank 1 valuation of and its extension to
. Let denote the valuation ring of . The purpose
of this paper is to present a refined version of MacLane's theory of key
polynomials, similar to those considered by M. Vaqui\'e, and reminiscent of
related objects studied by Abhyankar and Moh (approximate roots) and T.C. Kuo.
Namely, we associate to a countable well ordered set the are called {\bf key
polynomials}. Key polynomials which have no immediate predecessor are
called {\bf limit key polynomials}. Let .
We give an explicit description of the limit key polynomials (which may be
viewed as a generalization of the Artin--Schreier polynomials). We also give an
upper bound on the order type of the set of key polynomials. Namely, we show
that if then the set of key polynomials has
order type at most , while in the case
this order type is bounded above by , where stands
for the first infinite ordinal.Comment: arXiv admin note: substantial text overlap with arXiv:math/060519
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