Search for the Lepton-Flavor-Violating Decays B-s(0) -> e(+/-)mu(-/+) and B-0 -> e(+/-)mu(-/+)

A search for the lepton-flavor-violating decays B0s\u2192e\ub1\u3bc 13 and B0\u2192e\ub1\u3bc 13 is performed with a data sample, corresponding to an integrated luminosity of 1.0\u2009\u2009fb 121 of pp collisions at s 1a=7\u2009\u2009TeV, collected by the LHCb experiment. The observed number of B0s\u2192e\ub1\u3bc 13 and B0\u2192e\ub1\u3bc 13 candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be \u212c(B0s\u2192e\ub1\u3bc 13)<1.1(1.4) 710 128 and \u212c(B0\u2192e\ub1\u3bc 13)<2.8(3.7) 710 129 at 90% (95%) confidence level (C.L.). These limits are a factor of 20 lower than those set by previous experiments. Lower bounds on the Pati-Salam leptoquark masses are also calculated, MLQ(B0s\u2192e\ub1\u3bc 13)>101\u2009\u2009TeV/c2 and MLQ(B0\u2192e\ub1\u3bc 13)>126\u2009\u2009TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds

Expression of Interest for a Phase-II LHCb Upgrade: Opportunities in flavour physics, and beyond, in the HL-LHC era

A Phase-II Upgrade is proposed for the LHCb experiment in order to take full advantage of the flavour-physics opportunities at the HL-LHC, and other topics that can be studied with a forward spectrometer. This Upgrade, which will be installed in Long Shutdown 4 of the LHC (2030), will build on the strengths of the current experiment and the Phase-I Upgrade, but will consist of re-designed sub-systems that can operate at a luminosity of 2×1034cm−2s−1, ten times that of the Phase-I Upgrade detector. New and improved detector components will increase the intrinsic performance of the experiment in certain key areas. In particular the installation of a tungsten sampling electromagnetic calorimeter will widen LHCb's capabilities for decays involving π0 and η mesons, electrons, and photons from loop-level penguin processes. The physics motivation is presented, and the prospects for operating the LHCb Interaction Point at high luminosity are assessed. The challenges for the detector are described and possible solutions are discussed. Finally, the key R\&amp;D areas are summarised, together with a set of initial modifications suitable for implementation during Long Shutdown 3 (2024--2026)