### Higgs Physics

Higgs observables are also included wihtin the list of physical
observables currently available in the $\texttt{HEPfit}$ code. These
include the experimental measurements for the Higgs signal strengths measured
by the ATLAS and CMS collaborations at the LHC at 7 and 8 TeV, as well
as from CDF and D0 at Tevatron. All the individual experimental categories
are available for the following final states:

- $H\rightarrow \gamma\gamma$
- $H\rightarrow Z Z$
- $H\rightarrow W^+ W^-$
- $H\rightarrow \tau^+ \tau^-$
- $H\rightarrow b \bar{b}$

The theoretical predictions for these signal strengths can be computed as
\begin{equation}
\mu = \sum_i w_i r_i,\nonumber
\end{equation}
where the sum runs over all the production mechanism that can contribute to each category.
The weights and individual signal strength for each channel are given by
\begin{equation}
w_i=\frac{\epsilon_i \left[\sigma_\mathrm{SM}\times\mathrm{BR}_\mathrm{SM}\right]_i}{\sum_j \epsilon_j^\mathrm{SM} \left[\sigma_\mathrm{SM}\times\mathrm{BR}_\mathrm{SM}\right]_j},
~~~~r_i=\frac{\left[\sigma\times\mathrm{BR}\right]_i}{\left[\sigma_\mathrm{SM}\times\mathrm{BR}_\mathrm{SM}\right]_i}.\nonumber
\end{equation}
The experimental efficiencies, $\epsilon_i$, are taken to be approximately equal to the
Standard Model ones, which is a good approximation if new physics effects are small.

In the current version of $\texttt{HEPfit}$ the theoretical predictions for Higgs
observables are implemented for the following new physics scenarios:

- The Standard Model with modified Higgs couplings ($\kappa_{V}$, $\kappa_f$).
- The dimension six Standard Model Effective Lagrangian.
- Two-Higgs-Doublet models.