Hunting down the X17 boson at the CERN SPS

Investigation of a light Dark Boson existence: The New JEDI project

Several experiments around the world are looking for a new particle, named Dark Boson, which may do the link between the Ordinary Matter (which forms basically stars, planets, interstellar gas...) and the Hidden Sectors of the Universe. This particle, if it exists, would act as the messenger of a new fundamental interaction of nature. In this paper, the underlying Dark Sectors theory will be introduced first. A non-exhaustive summary of experimental studies carried out to date and foreseen in the incoming years will be presented after,including the 8Be anomaly. The last section will provide a status of the New JEDI**** project which aims to investigate the existence or not of a Dark Boson in the MeV range.

Neutrino communication, intergalactic transit, and Astrobiology

This is a brief summary, snapshot, of a few issues that relate to possible communication with Extraterrestrial Intelligence (ETI) using neutrinos. Essentially, more research is required to better understand possible detection and communication with intelligent life (Astrobiology and ETI). Because of the possible scarcity of life in any single galaxy, to enhance the possibility of life detection, inter-galactic transit neutrinos necessitate consideration. Neutrino-based potential communications are inferred as the optimal mechanism or venue for detection of communications from ETI as well as sending communications to ETI. A paradox exists within this central theme. On the one hand, neutrino technology should be further developed and used to receive signals from or to send signals to ETI, because they transit inter-galactic distances. On the other hand, however, neutrinos have a very low cross-section interaction and are very difficult to detect. This concise Editorial incorporates several diverse research areas. Various issues are briefly and conjointly mentioned to inform the reader of multiple fields required towards a deeper understanding of astrobiology, astro virology, and ETI. This understanding is required for future advances, just as innovations in classical physics, quantum mechanics, particle physics, biophysics, chemistry, biochemistry, and molecular biology were required for the breakthroughs and advances in biology and virology, from the last century to the present - thus, the need for innovations and applications in neutrino particle physics research.

Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel

We report the results of a search for a new vector boson ( A ' ) decaying into two dark matter particles χ 1 χ 2 of different mass. The heavier χ 2 particle subsequently decays to χ 1 and an off-shell Dark Photon A ' ∗ → e + e - . For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained re-analyzing the previous NA64 searches for an invisible decay A ' → χ χ ¯ and axion-like or pseudo-scalar particles a → γ γ . With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for A ' masses from 2 m e up to 390 MeV and mixing parameter ε between 3 × 10 - 5 and 2 × 10 - 2 .

Constraints on New Physics in Electron g-2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector

We performed a search for a new generic X boson, which could be a scalar (S), pseudoscalar (P), vector (V), or an axial vector (A) particle produced in the 100 GeV electron scattering off nuclei, e^{-}Z→e^{-}ZX, followed by its invisible decay in the NA64 experiment at CERN. No evidence for such a process was found in the full NA64 dataset of 2.84×10^{11} electrons on target. We place new bounds on the S, P, V, A coupling strengths to electrons, and set constraints on their contributions to the electron anomalous magnetic moment a_{e}, |Δa_{X}|≲10^{-15}-10^{-13} for the X mass region 1  MeV≲m_{X}≲1  GeV. These results are an order of magnitude more sensitive compared to the current accuracy on a_{e} from the electron g-2 experiments and recent high-precision determination of the fine structure constant.