Top and bottom tensor couplings from a color octet scalar

We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and W bosons. We use known constraints on the parameters of the model to compare the predicted size of these couplings with existing phenomenological constraints.Comment: References added, matches accepted version for publicatio

Validity of two Higgs doublet models with a scalar color octet up to a high energy scale

We have recently studied theoretical constraints on the parameters of a 2HDM augmented with a color-octet scalar. In this paper we consider the consequences of requiring the model to remain valid up to very high energy scales, such as the GUT scale. The acceptable region of parameter space is reduced when one insists on vacuum stability, perturbative unitarity and the absence of Landau poles below a given scale. As the scale to which we require the model to be valid is increased, the acceptable region of parameter space for the 2HDM sector is reduced in such a way that it approaches the alignment limit, $\cos(\beta-\alpha)\to 0$, and the masses of $H^0$, $A$ and $H^\pm$ are pushed closer to each other. The parameters of the color octet sector are also restricted to an increasingly smaller region.Comment: 16 pages, 5 figures; referenced added; typos fixe

T-odd correlations from top-quark CEDM in lepton plus jets top-pair events

There exist several recent studies of the top-quark CEDM in the context of searching for CP violating signals in top-quark pair production at the LHC. Most of these studies constrain the CEDM either from deviations in the top-pair cross section from its standard model value, or from T-odd asymmetries in the dimuon channel. Motivated by ATLAS and CMS interest, we extend the study of T-odd asymmetries to the lepton plus jets channel. At the parton level, using MadGraph, we identify the most promising signals and their statistical sensitivity. We find that the signals with larger sensitivity to the CEDM require distinguishing between $b$ and $\bar{b}$ jets and propose a simple way to address this.Comment: 12 pages, 2 tables, 1 figur

Two Higgs doublet models augmented by a scalar color octet

The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet models (2HDM). In this paper we extend those studies to include constraints on the one loop couplings of the Higgs to gluons and photons. These couplings are particularly sensitive to the existence of new colored particles that are hard to detect otherwise and we use them to constrain a 2HDM augmented with a color-octet scalar, a possibility motivated by minimal flavor violation. We first study theoretical constraints on this model and then compare them with LHC measurements.Comment: 23 pages, 10 figures; Matched the publication versio