12,201,539 research outputs found
P- and T-violating form factor
The form factor of the parity and time-reversal violating (PTV) pion-nucleon
interaction is calculated from one-loop vertex diagrams. The degrees of freedom
included in the effective lagrangian are nucleons, pions, , and
mesons. We show that by studying the form factor one can constrain the
PTV meson-nucleon coupling constants. We evaluate the mean square radius
associated with the PTV vertex. Using the mean square radius, we
estimate the effect of the PTV vertex on the neutron electric dipole
moment, and find a very small correction. We also extract the renormalisation
group function and use it to discuss evolution of the PTV
coupling constant beyond the hadronic mass scale.Comment: 14 pages, 2 figures. Added discussion of neutron EDM; to be published
in Nucl.Phys.
Sylvester-t' Hooft generators of sl(n) and sl(n|n), and relations between them
Among the simple finite dimensional Lie algebras, only sl(n) possesses two
automorphisms of finite order which have no common nonzero eigenvector with
eigenvalue one. It turns out that these automorphisms are inner and form a pair
of generators that allow one to generate all of sl(n) under bracketing. It
seems that Sylvester was the first to mention these generators, but he used
them as generators of the associative algebra of all n times n matrices Mat(n).
These generators appear in the description of elliptic solutions of the
classical Yang-Baxter equation, orthogonal decompositions of Lie algebras, 't
Hooft's work on confinement operators in QCD, and various other instances. Here
I give an algorithm which both generates sl(n) and explicitly describes a set
of defining relations. For simple (up to center) Lie superalgebras, analogs of
Sylvester generators exist only for sl(n|n). The relations for this case are
also computed.Comment: 14 pages, 6 figure
On Isosystolic Inequalities for T^n, RP^n, and M^3
If a closed smooth n-manifold M admits a finite cover whose Z/2Z-cohomology
has the maximal cup-length, then for any riemannian metric g on M, we show that
the systole Sys(M,g) and the volume Vol(M,g) of the riemannian manifold (M,g)
are related by the following isosystolic inequality: Sys(M,g)^n \leq n!
Vol(M,g). The inequality can be regarded as a generalization of Burago and
Hebda's inequality for closed essential surfaces and as a refinement of Guth's
inequality for closed n-manifolds whose Z/2Z-cohomology has the maximal
cup-length. We also establish the same inequality in the context of possibly
non-compact manifolds under a similar cohomological condition. The inequality
applies to (i) T^n and all other compact euclidean space forms, (ii) RP^n and
many other spherical space forms including the Poincar\'e dodecahedral space,
and (iii) most closed essential 3-manifolds including all closed aspherical
3-manifolds.Comment: 34 pages, 0 figures. v2 contains expository revisions and some
additional reference
Central American Temnocerus Thunberg, 1815 (Coleoptera: Rhynchitidae)
Twenty eight species of Temnocerus Thunberg, 1815 are recognized from Central America (Mexico to Panama) with eight previously described species and 20 new species as follows: T. abdominalis (Voss), T. chiapensis n. sp., T. chiriquensis (Sharp), T. confertus (Sharp), T. cyaneus n. sp., T. ellus n. sp., T. giganteus n. sp., T. guatemalenus (Sharp), T. guerrerensis n. sp., T. herediensis n. sp., T. mexicanus n. sp., T. michoacensis n. sp., T. minutus n. sp., T. niger n. sp., T. oaxacensis n. sp., T. obrieni, n. sp., T. oculatus (Sharp), T. potosi n. sp., T. pseudaeratus n. sp., T. pueblensis n. sp., T. pusillus (Sharp), T. regularis (Sharp), T. rostralis n. sp., T. rugosus n. sp., T. salvensis n. sp., T. tamaulipensis n. sp., T. thesaurus (Sharp) and T. yucatensis n. sp. Rhynchites debilis Sharp is placed in synonymy with Temnocerus guatemalenus (Sharp) and Pselaphorhynchites lindae Hamilton is placed in synonymy with Temnocerus regularis (Sharp). A key to species based on external characters and male genitalia is provided as well as digital images, aedeagus drawings, and map distributions
deformations with supersymmetry
We investigate the behaviour of two-dimensional quantum field theories with
supersymmetry under a deformation induced by the
`' composite operator. We show that the deforming operator can be
defined by a point-splitting regularisation in such a way as to preserve
supersymmetry. As an example of this construction, we work
out the deformation of a free theory and compare to that
induced by the Noether stress-energy tensor. Finally, we show that the
supersymmetric deformed action actually possesses
symmetry, half of which is non-linearly realised
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