9,922 research outputs found
FCNC Top Quark Production via Anomalous Couplings
We calculate flavor-changing neutral current (FCNC) processes with top-quark
production via anomalous couplings at LHC energies. We report on progress on
the FCNC processes gu -> tZ, gu -> t gamma and gu -> tg. We go beyond leading
order and include soft-gluon corrections through next-to-next-to-leading order.Comment: 5 pages, 3 figures; presented at DPF 2013, Santa Cruz, California,
August 13-17, 201
On sets of points with few odd secants
We prove that, for odd, a set of points in the projective plane
over the field with elements has at least odd secants, where is
a constant and an odd secant is a line incident with an odd number of points of
the set.Comment: Revised versio
Point regular groups of automorphisms of generalised quadrangles
We study the point regular groups of automorphisms of some of the known
generalised quadrangles. In particular we determine all point regular groups of
automorphisms of the thick classical generalised quadrangles. We also construct
point regular groups of automorphisms of the generalised quadrangle of order
obtained by Payne derivation from the classical symplectic
quadrangle . For with we obtain at least two
nonisomorphic groups when and at least three nonisomorphic groups
when or . Our groups include nonabelian 2-groups, groups of exponent 9
and nonspecial -groups. We also enumerate all point regular groups of
automorphisms of some small generalised quadrangles.Comment: some minor changes (including to title) after referee's comment
Food-chain competition influences gene's size
We have analysed an effect of the Bak-Sneppen predator-prey food-chain
self-organization on nucleotide content of evolving species. In our model,
genomes of the species under consideration have been represented by their
nucleotide genomic fraction and we have applied two-parameter Kimura model of
substitutions to include the changes of the fraction in time. The initial
nucleotide fraction and substitution rates were decided with the help of random
number generator. Deviation of the genomic nucleotide fraction from its
equilibrium value was playing the role of the fitness parameter, , in
Bak-Sneppen model. Our finding is, that the higher is the value of the
threshold fitness, during the evolution course, the more frequent are large
fluctuations in number of species with strongly differentiated nucleotide
content; and it is more often the case that the oldest species, which survive
the food-chain competition, might have specific nucleotide fraction making
possible generating long genesComment: 11 pages including 7 figure
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