5 research outputs found
On electroweak baryogenesis in the littlest Higgs model with T parity
We study electroweak baryogenesis within the framework of the littlest Higgs
model with T parity. This model has shown characteristics of a strong
first-order electroweak phase transition, which is conducive to baryogenesis in
the early Universe. In the T parity symmetric theory, there are two gauge
sectors, viz., the T-even and the T-odd ones. We observe that the effect of the
T-parity symmetric interactions between the T-odd and the T-even gauge bosons
on gauge-higgs energy functional is quite small, so that these two sectors can
be taken to be independent. The T-even gauge bosons behave like the Standard
Model gauge bosons, whereas the T-odd ones are instrumental in stabilizing the
Higgs mass. For the T-odd gauge bosons in the symmetric and asymmetric phases
and for the T-even gauge bosons in the asymmetric phase, we obtain, using the
formalism of Arnold and McLerran, very small values of the ratio, (Baryon
number violation rate/Universe expansion rate). We observe that this result, in
conjunction with the scenario of inverse phase transition in the present work
and the value of the ratio obtained from the lattice result of sphaleron
transition rate in the symmetric phase, can provide us with a plausible
baryogenesis scenario.Comment: 13 pages, 2 figures, published version, references modifie
On the gauge and BRST invariance of the chiral QED with Faddeevian anomaly
Chiral Schwinger model with the Faddeevian anomaly is considered. It is found
that imposing a chiral constraint this model can be expressed in terms of
chiral boson. The model when expressed in terms of chiral boson remains
anomalous and the Gauss law of which gives anomalous Poisson brackets between
itself. In spite of that a systematic BRST quantization is possible. The
Wess-Zumino term corresponding to this theory appears automatically during the
process of quantization. A gauge invariant reformulation of this model is also
constructed. Unlike the former one gauge invariance is done here without any
extension of phase space. This gauge invariant version maps onto the vector
Schwinger model.The gauge invariant version of the chiral Schwinger model for
has a massive field with identical mass however gauge invariant version
obtained here does not map on to that.Comment: 11 pages latex, no figures, A little change in Title and abstrac
Study of Einstein-bumblebee gravity with Kerr-Sen-like solution in the presence of a dispersive medium
A Kerr-Sen-like black hole solution appears in the Einstein-bumblebee theory of gravity. The solution contains contains a Lorentz violating parameter in an explicit manner. We study the null geodesics in the background of this Kerr-Sen-like black hole surrounded by a dispersive medium like plasma. We investigate the effect of the charge of the black hole, the Lorentz violation parameter, and the plasma parameter on the photon orbits with the evaluation of the effective potential in the presence of both the Lorentz violation parameter and the plasma parameter. We also study the influence of the Lorentz violation parameter and plasma parameter on the emission of energy from the black hole due to thermal radiation. Besides, we compute the angle of deflection of massless particles with weak-field approximation in this generalized situation and examine how it varies with the Lorentz violation parameter in presence of plasma. Constraining the parameters of this Lorentz violating Kerr-Sen-like black hole is also attempted here with the result obtained from the observations of the Event Horizon Telescope (EHT) collaboration