8 research outputs found
Parity violation in four and higher dimensional spacetime with torsion
The possibility of parity violation in a gravitational theory with torsion is
extensively explored in four and higher dimensions. In the former case,we have
listed our conclusions on when and whether parity ceases to be conserved, with
both two-and three-index antisymmetry of the torsion field. In the latter, the
bulk spacetime is assumed to have torsion, and the survival of parity-violating
terms in the four dimensional effective action is studied, using the
compactification schemes proposed by Arkani-Hamed-Dimopoulos-Dvali and
Randall-Sundrum. An interesting conclusion is that the torsion-axion duality
arising in a stringy scenario via the second rank antisymmetric Kalb-Ramond
field leads to conservation of parity in the gravity sector in any dimension.
However, parity-violating interactions do appear for spin 1/2 fermions in such
theories, which can have crucial phenomenological implications.Comment: 13 Pages, Latex, Title changed and thoroughly revised. To appear in
Eur.Phys.J.
Parity Violating Gravitational Coupling Of Electromagnetic Fields
A manifestly gauge invariant formulation of the coupling of the Maxwell
theory with an Einstein Cartan geometry is given, where the space time torsion
originates from a massless Kalb-Ramond field augmented by suitable U(1) Chern
Simons terms.We focus on the situation where the torsion violates parity, and
relate it to earlier proposals for gravitational parity violation.Comment: 7 Pages, Latex . no figures, Replaced with Revtex version, many
references added and typos correcte
How large could the R-parity violating couplings be?
We investigate in detail the predictions coming from the d=4 operators for
proton decay. We find the most general constraints for the R-parity violating
couplings coming from proton decay, taking into account all fermion mixing and
in different supersymmetric scenarios.Comment: 8 pages, several corrections, to appear in J.Phys.G (2005
Matter-gravity interaction in a multiply warped braneworld,
The role of a bulk graviton in predicting the signature of extra dimensions
through collider-based experiments is explored in the context of a multiply
warped spacetime. In particular it is shown that in a doubly warped braneworld
model, the presence of the sixth dimension, results in enhanced concentration
of graviton Kaluza Klein (KK) modes compared to that obtained in the usual
5-dimensional Randall-Sundrum model. Also, the couplings of these massive
graviton KK modes with the matter fields on the visible brane turn out to be
appreciably larger than that in the corresponding 5- dimensional model. The
significance of these results are discussed in the context of KK graviton
search at the Large Hadron Collider (LHC).Comment: 13 pages, 2 table
Does curvature–dilaton coupling with a Kalb–Ramond field lead to an accelerating Universe?
Kalb–Ramond field localization on the Bloch brane
This work deals with new results on the Kalb-Ramond (KR) field localization
in braneworld models. We consider a five-dimensional warped spacetime with an
embedded 4D thick brane which is generated by two real scalar fields coupled
with gravity (the so called Bloch brane). We find a KR field zero mode
localized with the inclusion of the dilaton coupling. Analyzing the massive
spectrum, we detected a series of resonant modes that arise from the solutions
of the Schr\"odinger-like equation for KR field. The effects of the brane
thickness and of the dilaton coupling over the resonance structures are
determined. Such analysis is extended to the resonance lifetimes of the massive
modes, allowing a better understanding on the localization mechanism of the
model.Comment: 18 pages, 6 figure