5 research outputs found
Differential geometry construction of anomalies and topological invariants in various dimensions
In the model of extended non-Abelian tensor gauge fields we have found new
metric-independent densities: the exact (2n+3)-forms and their secondary
characteristics, the (2n+2)-forms as well as the exact 6n-forms and the
corresponding secondary (6n-1)-forms. These forms are the analogs of the
Pontryagin densities: the exact 2n-forms and Chern-Simons secondary
characteristics, the (2n-1)-forms. The (2n+3)- and 6n-forms are gauge invariant
densities, while the (2n+2)- and (6n-1)-forms transform non-trivially under
gauge transformations, that we compare with the corresponding transformations
of the Chern-Simons secondary characteristics. This construction allows to
identify new potential gauge anomalies in various dimensions.Comment: 27 pages, references added, matches published versio
Non-BPS Dyons and Branes in the Dirac-Born-Infeld Theory
Non-BPS dyon solutions to D3-brane actions are constructed when one or more
scalar fields describing transverse fluctuations of the brane, are considered.
The picture emerging from such non-BPS configurations is analysed, in
particular the response of the D-brane-string system to small perturbations.Comment: 16 pages, 4 figures, Revtex fil
Soft Photons in Hadron-Hadron Collisions: Synchrotron Radiation from the QCD Vacuum?
We discuss the production of soft photons in high energy hadron-hadron
collisions. We present a model where quarks and antiquarks in the hadrons emit
``synchrotron light'' when being deflected by the chromomagnetic fields of the
QCD vacuum, which we assume to have a nonperturbative structure. This gives a
source of prompt soft photons with frequencies in the c.m.
system of the collision in addition to hadronic bremsstrahlung. In comparing
the frequency spectrum and rate of ``synchrotron'' photons to experimental
results we find some supporting evidence for their existence. We make an
exclusive--inclusive connection argument to deduce from the ``synchrotron''
effect a behaviour of the neutron electric formfactor proportional
to for . We find this to be consistent with
available data. In our view, soft photon production in high energy
hadron-hadron and lepton-hadron collisions as well as the behaviour of
electromagnetic hadron formfactors for low are thus sensitive probes of
the nonperturbative structure of the QCD vacuum.Comment: Heidelberg preprint HD-THEP-94-36, 31 pages, LaTeX + ZJCITE.sty
(included), 12 figures appended as uuencoded compressed ps-fil