Speaker
Description
We present the inelastic scattering between $\gamma\gamma$ into/out of a strongly interacting EWSBS satisfying unitarity. The matrix elements $V_L V_L\to V_L V_L $, $V_L V_L \to hh$, $hh\to hh$, $V_L V_L \to \gamma \gamma$ and $hh \to \gamma \gamma$ are al computed to NLO in perturbation theory with the Nonlinear Effective Theory of the EWSBS (within the Equivalence Theorem).
Describing the EWSBS itself requires seven parameters: two LO parameters ($a$, $b$) and the NLO counterterms ($a_4$, $a_5$, $g$, $d$, $e$). The coupling with the $\gamma\gamma$ state requires four additional ones:
$c_{\gamma\gamma}$ and $a1$, $a2$, $a3$, though in the combination $a_1-a_2+a_3$ only, so the number of total coefficients is 9.
By means of a modified version of the IAM and N/D unitarization procedures, we study the prospects for detecting any new strong-EWSBS resonances in the energy range 0.75-3TeV, within reach of the LHC. Our basic assumption is that the couplings with $\gamma\gamma$ are feeble as they are governed by the electromagnetic $\alpha_{\rm ew}$, while the EWSBS is strongly interacting.
There are two cases of interest. First, the detection of resonances in the diphoton channel coming from the strong rescattering of $V_L V_L$ states (photons in the final state). And second, the possible study of $\gamma\gamma$ scattering at the LHC by means of the new forward detectors (CMS-TOTEM and ATLAS-AFP) that tag the elastically scattered proton (photons in the initial state). Of course, this would be also a goal for the ILC and its future detectors.
