Detecting Dark Photons with Reactor Neutrino Experiments

Search for Reactor-Produced Millicharged Particles with Skipper-CCDs at the CONNIE and Atucha-II Experiments

Millicharged particles, proposed by various extensions of the standard model, can be created in pairs by high-energy photons within nuclear reactors and can interact electromagnetically with electrons in matter. Recently, the existence of a plasmon peak in the interaction cross section with silicon in the eV range was highlighted as a promising approach to enhance low-energy sensitivities. The CONNIE and Atucha-II reactor neutrino experiments utilize Skipper-CCD sensors, which enable the detection of interactions in the eV range. We present world-leading limits on the charge of millicharged particles within a mass range spanning 6 orders of magnitude, derived through a comprehensive analysis and the combination of data from both experiments.

New Directions for Axionlike Particle Searches Combining Nuclear Reactors and Haloscopes

In this Letter, we propose reactoscope, a novel experimental setup for axionlike particle (ALP) searches. Nuclear reactors produce a copious number of photons, a fraction of which could convert into ALPs via Primakoff process in the reactor core. The generated flux of ALPs leaves the nuclear power plant and its passage through a region with a strong magnetic field results in the efficient conversion to photons that can be detected. Such magnetic field is the key component of axion haloscope experiments. Adjacent nuclear reactor and axion haloscope experiments exist in Grenoble, France. There, the Institut Laue-Langevin research reactor is situated only ∼700  m from GrAHal, the axion haloscope platform designed to offer several volume and magnetic field (up to 43 T) configurations. We derive sensitivity projections for photophilic ALP searches with the institute and GrAHal, and also scrutinize analogous realizations, such as the one comprising the Axion Solar Telescope experiment at CERN and the Bugey nuclear power plant. The results that we obtain complement and extend the reach of existing laboratory experiments, e.g., the light-shining-through-walls experiment. While the derived sensitivities are not competitive when compared to the astrophysical limits, our analysis is free from the assumptions associated with those limits.

Severe Constraints on New Physics Explanations of the MiniBooNE Excess

The MiniBooNE experiment has recently reported an anomalous 4.5σ excess of electronlike events consistent with ν_{e} appearance from a ν_{μ} beam at short baseline. Given the lack of corresponding ν_{μ} disappearance observations, required in the case of oscillations involving a sterile flavor, there is strong motivation for alternative explanations of this anomaly. We consider the possibility that the observed electronlike signal may actually be initiated by particles produced in the MiniBooNE target, without involving new sources of neutrino production or any neutrino oscillations. We find that the electronlike event energy and angular distributions in the full MiniBooNE dataset, including neutrino, antineutrino, and beam dump modes, severely limit and, in some cases, rule out new physics scenarios as an explanation for the observed neutrino and antineutrino mode excesses. Specifically, scenarios in which the particle produced in the target either decays (visibly or semivisibly) or scatters elastically in the detector are strongly disfavored. Using generic kinematic arguments, we extend the existing MiniBooNE results and interpretations to exhaustively constrain previously unconsidered new physics signatures and emphasize the power of the MiniBooNE beam dump search to further limit models for the excess.

Constraints on Hidden Photons Produced in Nuclear Reactors

New light vector particles-hidden photons-are present in many extensions of the standard model of particle physics. They can be produced in nuclear reactors and registered by neutrino detectors. We obtain new limits on the models with the hidden photons from an analysis of published results of the TEXONO neutrino experiment. Accounting for oscillations between the visible and hidden photons, we find that the neutrino experiments are generally insensitive to the hidden photons lighter than ∼0.1  eV.

Oscillations to hidden photon in reactor and accelerator experiments

Possible connection between visible and hidden Worlds of particle physics is provided by the vector portal interaction, that is kinetic mixing between ordinary (visible) and hidden photons. If sufficiently light, the hidden photon can be produced (and absorbed) by ordinary matter in a Compton-like processes, which naively are insensitive to the hidden photon mass. In this talk we study the evolution of the two vector boson system, which exhibits oscillations similar to the well-known neutrino oscillations. We show that, provided by the environment matter, this quantum phenomenon significantly suppresses the hidden photon production in particle collisions. The ordinary photon is effectively massive in the media. The suppression is important for hidden photon lighter than photon in the corresponding media (detector, beam dump material etc) and grows with decrease of the hidden photon mass making all the accelerator and reactor experiments absolutely insensitive to the models with light photons. The dedicated study is required for the case of the degenerate photon and hidden photon, when, on the contrary, the hidden photon production can be amplified with respect to the Compton process.