Measurements of $\gamma \gamma \to \text{mbox}Higgs$ and $\gamma \gamma \to W^{+}{W}^{-}$ in $e^{+}{e}^{-}$ collisions at the Future Circular Collider

Abstract

The measurements of the two-photon production of the Higgs boson and of $W^{\pm }$ boson pairs in $e^{+}{e}^{-}$ collisions at the Future Circular Collider (FCC-ee) are investigated. The processes $e^{+}{e}^{-}\stackrel{\gamma \gamma }{\to }{e}^{+}\mathrm{H}{e}^{-},e^{+}{\mathrm{W}}^{+}{\mathrm{W}}^{-}{e}^{-}$ are computed using the effective photon approximation for electron-positron beams, and studied in their $\mathrm{H}\to b\bar{b}$ and ${\mathrm{W}}^{+}{\mathrm{W}}^{-}\to 4j$ decay final-states including parton showering and hadronization, jet reconstruction, $e^{\pm }$ forward tagging, and realistic experimental cuts. After selection criteria, up to 75 Higgs bosons and 6600 ${\mathrm{W}}^{\pm }$ pairs will be reconstructed on top of controllable continuum backgrounds at $\sqrt{s}=$240 and 350 GeV for the total expected integrated luminosities, by tagging the scattered $e^{\pm }$ with near-beam detectors. A 5$\sigma$ observation of $\gamma \gamma \to$H is thereby warranted, as well as high-statistics studies of triple $\gamma \mathrm{WW}$ and quartic $\gamma \gamma \mathrm{WW}$ electroweak couplings, improving by at least factors of 2 and 10 the current limits on dimension-6 anomalous quartic gauge couplings.

Comments: Presented at EDS Blois 2017 Conference , Prague, Czech Republic, June 26--30, 2017