Exclusive $\Upsilon$ and $\rho(770)^0$ photoproduction in pPb at $\sqrt{s_{NN}} = 5.02$~TeV with CMS

The first measurements of exclusive $\Upsilon$ and $\rho(770)^0$ vector meson photoproduction with the CMS detector at LHC in ultraperipheral proton-lead collisions at $\sqrt{s_{NN}} = 5.02\text{TeV}$ are presented. The $\Upsilon(1S)$ cross section, which has been measured in the dumuon channel, is consistent with the updated ZEUS $\text{e}\text{p}$ results at HERA. A fit of function $A\,(W_{\gamma\text{p}}[\text{GeV}]/400)^{\delta}$ to the CMS $\text{p}\text{Pb}$ measurement together with HERA $\text{e}\text{p}$ and LHCb $\text{p}\text{p}$ data gives the $\delta$ value, consistent with $\text{J}/\psi$ photoproduction results. The obtained result provides a new insight for low-x gluon distribution in protons in an energyrange previously less constrained. The cross section for exclusive photoproduction of $\rho(770)^0$ has been measured where $\rho(770)^0$ decays to two pions. The obtained pomeron slope parameter, $\alpha' = 0.28 \pm 0.11 \text{(stat)} \pm 0.12 \text{(syst)} \text{GeV}^{-2}$, is consistent with the ZEUS result and with the Gribov-Regge theory expectation.