Exclusive particle production in pp and pPb collisions at CMS

Exclusive processes provide a useful method to study a broad range of high energy physics fields from gluon density evolutions to searches for new physics. Three measurements from the CMS experiment are reviewed. Exclusive $\pi\pi$ production is studied in proton-proton collisions. Low mass meson resonances are observed in the invariant mass distribution of pion pairs. The total exclusive $\pi^+\pi^-$ cross section is also measured in the $p_T(\pi) > 0.2$~GeV, $\lvert y \rvert < 2$ region yielding $26.5 \pm 0.3\,\text{(stat)}\,\pm 5.0\,\text{(syst)}\,\pm 1.1\,\text{(lumi)}~\mu$b. The photoproduction of $\Upsilon(nS)$ mesons is observed in ultraperipherial pPb collisions. The differential cross sections are measured as a function of $\lvert t \rvert$ and $y$. The comparison with previous measurements and theoretical models provides a better understanding of the gluon density evolution at low $x$ values. Evidence for the $\gamma\gamma \rightarrow \text{W}^{+}\text{W}^{-}$ process is shown with a $3.7\sigma$ observed significance. According to the results, limits on anomalous quartic gauge couplings can be provided.