Evidence for an $\eta_c(1S)\pi^-$ exotic resonance at LHCb and development of the Experiment Control System for the RICH upgrade

The first Dalitz plot analysis of $B^0 \to \eta_c(1S)K^+\pi^-$ decays using the data collected by the LHCb detector is presented. A satisfactory description of the data is obtained when including a contribution representing an exotic $\eta_c(1S) \pi^-$ resonant state. The significance of this exotic resonance, named $Z_c(4100)^-$, is more than three standard deviations, while its mass and width are $4096 \pm 20 ^{+18}_{-22}$ MeV and $152 \pm 58 ^{+60}_{-35}$ MeV, respectively. The spin-parity assignments $J^P=0^+$ and $J^{P}=1^-$ are both consistent with the data. In addition, the first measurement of the $B^0 \to \eta_c(1S)K^+\pi^-$ branching fraction is performed and gives $\displaystyle \mathcal{B}(B^0 \to \eta_c(1S)K^+\pi^-) = (5.73 \pm 0.24 \pm 0.13 \pm 0.66) \times 10^{-4}$, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions. In order to increase the potential of discovery in indirect searches for New Physics in the heavy-flavour sector, the LHCb experiment will undergo a major upgrade in 2019-2020, allowing the detector to operate with a five-fold increase in the instantaneous luminosity. Innovative data acquisition and trigger systems will be implemented, and a brand-new LHCb detector will be installed. The RICH detectors, being of crucial importance in the analyses performed by the LHCb collaboration, will be redesigned, with new photon detectors and front-end electronics. The development, test and characterisation of the the prototypes for the opto-electronics chain of the RICH upgrade, are reported. The development of the prototype of the Experiment Control System and of the Inventory, Bookkeeping and Connectivity database for the RICH upgrade are presented.