The PIP-II superconducting RF linac is currently under construction at Fermilab and is expected to be completed by the end of 2028. PIP-II is capable of operating in a continuous-wave mode and can concurrently supply 800 MeV protons to a mega-watt, GeV-scale beam dump facility and to LBNF/DUNE. Designs for proton accumulator rings are being studied to bunch the PIP-II protons into the short pulses needed for neutrino and low-mass dark matter experiments. PIP2-BD is a proposed 100-ton LAr scintillation-only experiment, whose detector design is inspired by CENNS-10 and CCM, that would have world-leading sensitivities to BSM physics, including low-mass dark matter produced in the PIP-II proton beam dump.

The gauged U(1)L mu-L Tau extension of the Standard Model is a very simple framework that can alleviate the tension in muon anomalous magnetic dipole moment, reinforced by the recent Fermilab measurement. We explore experimental probes of the (g - 2)mu target with a general treatment of kinetic mixing between the Z' gauge boson and the photon. The physical value of the kinetic mixing depends on a free parameter of the model and energy scale of a process. We find neutrino constraints on the (g - 2)mu target including Borexino, coherent elastic neutrino-nucleus scattering, and white dwarfs are sensitive to this freedom and can be lifted if the kinetic mixing lies in proximity of zero at low momentum transfer. As a further step, we explore L mu - L Tau charged dark matter with a thermal origin and show that the same scenario of kinetic mixing can relax existing direct detection constraints and predict novel recoil energy dependence in the upcoming searches. Future joint effort of neutrino and dark matter experiments and precision spectral measurement will be the key to test such a theory.

The gauged $U(1{)}_{{L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}}$ extension of the Standard Model is a very simple framework that can alleviate the tension in muon anomalous magnetic dipole moment, reinforced by the recent Fermilab measurement. We explore experimental probes of the $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$ target with a general treatment of kinetic mixing between the ${Z}^{\ensuremath{'}}$ gauge boson and the photon. The physical value of the kinetic mixing depends on a free parameter of the model and energy scale of a process. We find neutrino constraints on the $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$ target including Borexino, coherent elastic neutrino-nucleus scattering, and white dwarfs are sensitive to this freedom and can be lifted if the kinetic mixing lies in proximity of zero at low momentum transfer. As a further step, we explore ${L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}$ charged dark matter with a thermal origin and show that the same scenario of kinetic mixing can relax existing direct detection constraints and predict novel recoil energy dependence in the upcoming searches. Future joint effort of neutrino and dark matter experiments and precision spectral measurement will be the key to test such a theory.