Related papers: A custodial symmetry for Zbb
We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Zbb coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the…
We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Zbb coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the…
In the Standard Model for electroweak interactions, the Higgs sector is known to display a "custodial" symmetry protecting the mass relation m_{W^\pm}^2=m_{W_3}^2 from large corrections. When considering extensions of the scalar sector,…
We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Z b_L bbar_L coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner…
Electroweak precision measurements established that custodial symmetry is preserved to a good accuracy in the gauge sector after electroweak symmetry breaking. However, recent LHC results might be interpreted as pointing towards Higgs…
We present a class of composite Higgs models arising from a warped extra dimension that can satisfy all the electroweak precision tests in a significant portion of their parameter space. A custodial symmetry plays a crucial role in keeping…
The Standard Model with a light Higgs provides a very accurate description of the electroweak precision observables. The largest deviation between the Standard Model predictions and the experimental measurements, the forward-backward…
In this note, a ``littlest higgs'' model is presented which has an approximate custodial SU(2) symmetry. The model is based on the coset space $SO(9)/(SO(5)\times SO(4))$. The light pseudo-goldstone bosons of the theory include a {\it…
We discuss the implications of global symmetries on the radiative corrections to the Higgs sector. We focus on two examples: the charged Higgs mass in the minimal supersymmetric model and the Higgs couplings to vector boson pairs. In the…
It has been recently argued that realistic models with warped extra dimensions can have Kaluza-Klein particles accessible at the Large Hadron Collider if a custodial symmetry, SU(2)_V \times P_{LR}, is used to protect the T parameter and…
Higgs triplet models are known to have difficulties obtaining agreement with electroweak precision data and in particular constraints on the $\rho$ parameter. Either a global $SU(2)_L \otimes SU(2)_R$ symmetry has to be imposed on the…
The Randall-Sundrum scenario with Standard Model fields in the bulk and a custodial symmetry is considered. We determine the several minimal quark representations allowing to address the anomalies in the forward-backward b-quark asymmetry…
In this note we present a little Higgs model that has custodial SU(2) as an approximate symmetry. This theory is a simple modification of the ``Minimal Moose'' with SO(5) global symmetries protecting the Higgs mass. This allows for a simple…
While little Higgs models provide an interesting way to address the hierarchy problem, concrete models in the literature typically face two major obstacles. First, the mechanism for generating a Higgs quartic coupling often leads to large…
We consider one of the most significant deviations from the Standard Model: the forward-backward asymmetry of the b-quark measured at leptonic colliders. We investigate the possibility to solve this discrepancy by introducing new physics at…
We present "Custodial Naturalness" as a new mechanism to explain the separation between the electroweak (EW) scale and the scale of potential ultraviolet completions of the Standard Model (SM). We assume classical scale invariance as well…
The model proposed by Georgi and Machacek enables the Higgs sector to involve isospin triplet scalar fields while retaining a custodial $SU(2)_V$ symmetry in the potential and thus ensuring the electroweak $\rho$ parameter to be one at tree…
The concept of custodial symmetry, a residual symmetry that protects physical observables from large quantum corrections, has been a cornerstone of high-energy physics, but its experimental observation has remained unexplored. Building on…
In the present work, we elucidate the meaning of the custodial symmetry and its importance at the phenomenological level in the framework of the standard model of the electroweak interactions and its possible extensions.
We show how the symmetry breaking pattern of the simplest little Higgs model, and that of the smallest moose model that incorporates an approximate custodial SU(2), can be realized through the condensation of strongly coupled fermions. In…