4,118 research outputs found
Dependence of nucleotide physical properties on their placement in codons and determinative degree
Various physical properties such as dipole moment, heat of formation and
energy of the most stable formation of nucleotides and bases were calculated by
PM3 (modified neglect of diatomic overlap, parametric method number 3) and AM1
(Austin model 1) methods. As distinct from previous calculations, for
nucleotides the interaction with neighbours is taken into account up to
gradient of convergence equaling 1. The dependences of these variables from the
place in the codon and the determinative degree were obtained. The difference
of these variables for codons and anticodons is shown.Comment: 13 pages, 8 figures, PD
Factorization Approach for Inclusive Production of Doubly Heavy Baryon
We study inclusive production of doubly heavy baryon at a collider
and at hadron colliders through fragmentation. We study the production by
factorizing nonpertubative- and perturbative effects. In our approach the
production can be thought as a two-step process: A pair of heavy quarks can be
produced perturbatively and then the pair is transformed into the baryon. The
transformation is nonperturbative. Since a heavy quark moves with a small
velocity in the baryon in its rest frame, we can use NRQCD to describe the
transformation and perform a systematic expansion in the small velocity. At the
leading order we find that the baryon can be formed from two states of the
heavy-quark pair, one state is with the pair in state and in color
, another is with the pair in state and in color . Two matrix elements are defined for the transformation from the two
states, their perturbative coefficients in the contribution to the
cross-section at a collider and to the function of heavy quark
fragmentation are calculated. Our approach is different than previous
approaches where only the pair in state and in color is
taken into account. Numerical results for colliders at the two
-factories and for hadronic colliders LHC and Tevatron are given.Comment: Add results for large p_t, minor change
Exlusive charmed meson pair production
The experimental data of BELLE Collaboration on the exclusive charmed meson
pair production in the process of monophotonic -annihilation
() has been studied. It has been shown that
these data is described satisfactorily in the frame work of constituent quark
model. Our studies have demonstrated that the central production process
and the process of
monophotonic -annihilation yield comparable numbers of the charmed
meson pairs.Comment: 15 pages, 7 figures, RevTeX
BCVEGPY2.0: A upgrade version of the generator BCVEGPY with an addendum about hadroproduction of the -wave states
The generator BCVEGPY is upgraded by adding the hadroproduction of the
-wave excited states (denoted by or by and
) and by improving some features of the original one as well. We
denote it as BCVEGPY2.0. The -wave production is also calculated by taking
only the dominant gluon-gluon fusion mechanism (with the subprocess being dominated) into account as that for -wave. In
order to make the addendum piece of the upgraded generator as compact as
possible so as to increase its efficiency, we manipulate the amplitude as
compact as possible with FDC (a software for generating Feynman diagrams and
the algebra amplitudes, and for manipulating algebra formulae analytically etc)
and certain simplification techniques. The correctness of the program is tested
by checking the gauge invariance of the amplitude and by comparing the
numerical results with the existent ones in the literature carefully.Comment: 21 page, 4 figure
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