30,122 research outputs found
Three-dimensional quantum electrodynamics as an effective interaction
We obtain a Quantum Electrodynamics in 2+1 dimensions by applying a
Kaluza--Klein type method of dimensional reduction to Quantum Electrodynamics
in 3+1 dimensions rendering the model more realistic to application in
solid-state systems, invariant under translations in one direction. We show
that the model obtained leads to an effective action exhibiting an interesting
phase structure and that the generated Chern--Simons term survives only in the
broken phase.Comment: 10 pages in Plain Te
Lepton-Flavor Violation with Non-universal Soft Terms
We study the lepton-flavor violation processes tau ->mu gamma and mu->e gamma
in two different examples of models with non-universal soft breaking terms
derived from strings. We show that the predictions are quite different from
those of universal scenarios. Non-universal A-terms provide an interesting
framework to enhance the supersymmetric contributions to CP violation effects.
We observe that in the case of the lepton-flavor violation we study, the
non-universality of the scalar masses enhances the branching ratios more
significantly than the non-universality of the A-terms. We find that the
current experimental bounds on these processes restrict both the parameter
space of the models and the texture of the Yukawa couplings which predicts the
lepton masses, providing at the same time an interesting experimental test for
physics beyond the Standard Model.Comment: 15 pages, 6 figures minor change
Tetraquark Production in Double Parton Scattering
We develop a model to study tetraquark production in hadronic collisions. We
focus on double parton scattering and formulate a version of the color
evaporation model for the production of the and of the
tetraquark, a state composed by the quarks. We find that
the production cross section grows rapidly with the collision energy
and make predictions for the forthcoming higher energy data of the LHC.Comment: 13 pages, 3 figures. Corrections in the text and reference
- …