Related papers: Bounds on Flavor Gauge Bosons from Precision Elect…
There is current interest in a possible new massive gauge boson $X$ which mixes slightly with the $Z$ boson and accounts for certain anomalies in the LEP data. We show why constraints on models in which the $X$ boson does not couple to the…
We present an update of our ongoing study of the SU(2) gauge theory with one flavor of Dirac fermion in the adjoint representation. Compared to our previous results we now have data at larger lattice volumes, smaller values of the fermion…
We propose a model of quark flavor based on an additional $SU(2)\times U(1)$ local symmetry in a warped extra dimensional bulk. In contrast to other works, we break the additional gauge symmetry in the bulk via two complex scalars which…
The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…
Using recent D0 data on the dijet mass spectrum, we present a limit on flavor-universal colorons. At 95% CL we find Mc/cot(theta) > 837 GeV. We discuss the implications of this limit for models of quark compositeness, non-standard gluon…
We analyze the constraints on coloured scalar bosons imposed by the current LHC data at $\sqrt{s}=13$ TeV. Specifically, we consider an additional electroweak doublet of colour-octet scalars, satisfying the principle of Minimal Flavour…
Recently Nelson et al. proposed an interesting flavor symmetric model to account for the top quark forward-backward asymmetry and the dijet anomaly at CDF simultaneously with just three parameters: a coupling constant of order one, and two…
We consider the phenomenology of models in which electroweak symmetry breaking is triggered by new strong dynamics affecting the third generation and is transmitted to the light fermions via a fundamental Higgs doublet. While similar in…
We examine experimental constraints on scharm-stop flavor mixing in the minimal supersymmetric standard model, which arise from the experimental bounds on squark and Higgs boson masses, the precision measurements of W-boson mass and the…
The fit of precision electroweak data to the Minimal Standard Model currently gives an upper limit on the Higgs boson mass of 170 GeV at 95% confidence. Nevertheless, it is often said that the Higgs boson could be much heavier in more…
Effective Supersymmetry is presented as a theory of physics above the electroweak scale which has significant theoretical advantages over both the standard model and the Minimal Supersymmetric Standard Model (MSSM). The theory is…
Models of extended gauge mediation, in which large A-terms arise through direct messenger-MSSM superpotential couplings, are well-motivated by the discovery of the 125 GeV Higgs. However, since these models are not necessarily MFV, the…
The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the…
The triviality of the scalar sector of the standard one-doublet Higgs model implies that this model is only an effective low-energy theory valid below some cut-off scale $\Lambda$. The underlying high-energy theory must include flavor…
An insightful way of presenting the LHC limits on dijet resonances is the coupling-mass plot for a $Z'$ boson that has flavor-independent quark interactions. This also illustrates the comparison of low-mass LHC sensitivity with constraints…
The aim of the thesis is to study models of the electroweak symmetry breaking caused by dynamically generated masses of quarks and leptons. (1) We perform the basic analysis whether the main underlying idea, that the masses of only known…
The current status of the quantities entering into the global electroweak fits is reviewed, highlighting changes since Summer 2003. These data include the precision electroweak properties of the Z and W bosons, the top-quark mass and the…
We explore predictive flavor models based on subgroups of the standard-model $SU(3)^5$ flavor symmetry. Restricting to products of $SU(3)$, we find that a global $SU(3)^3$ flavor symmetry, broken only by two Yukawa spurions, leads to a…
We present an effective Lagrangian parameterization describing scalar, vector, and axial-vector bound states, originating from a strong breaking of the electroweak symmetry, based on the global symmetry $SU(N)_L\otimes SU(N)_R$. In this…
We review the empirical evidence for the validity of the Standard Electroweak Theory in nature. The experimental data are interpreted in terms of an effective Lagrangian for Z physics, allowing for potential sources of SU(2) violation and…