Researchers publish new outcomes from darkish boson searches

Positioned at CERN’s North Space and receiving beams from the Tremendous Proton Synchrotron (SPS), the NA64 and NA62 experiments seek for darkish matter, complementing searches on the LHC, as they cowl a special vitality vary. Each experiments have lately printed new outcomes. The analysis is printed on the arXiv preprint server.

Darkish matter doesn’t appear to work together with our seen world however makes up most of our universe. Researchers assume that the darkish sector interacts with the Normal Mannequin through so-called mediators. These mediators may very well be—as an example—a dark photon, a darkish scalar boson and an axion, which may very well be distinguished by how they work together with Normal Mannequin particles.

The NA62 experiment, which was designed to check the ultra-rare kaon decay right into a charged pion and two neutrinos, has now looked for attainable contributions from dark-matter particles to a different uncommon kaon decay. The researchers used a beam consisting primarily of pions and kaons, produced by firing the 400 GeV/c SPS proton beam onto a beryllium goal.

The uncommon kaon decay right into a pion and a pair of photons, subsequently decaying into two electron-positron pairs, is especially fascinating, as hypothetically, darkish bosons would decay into the identical closing states as Normal Mannequin photons.

Though the experimentalists didn’t discover proof for such a uncommon decay, nor for a darkish boson, they positioned probably the most stringent higher limits so far by analyzing information recorded in 2017 and 2018. As well as, the experimentalists excluded the axion as a attainable rationalization for the 17 MeV/c2 ATOMKI anomaly and thus confirmed previous findings by the NA64 experiment.

The NA64 collaboration hunts for invisible mild dark-matter particles that work together with Normal Mannequin particles by means of a attainable darkish photon. Utilizing electron collision information collected between 2016 and 2022, equivalent to 9.4 × 10¹¹ electrons heading in the right direction, NA64 began to probe the very thrilling area of parameter area predicted by two benchmark dark-matter fashions for the primary time.

Their information set excludes main sub-GeV dark-matter candidates with a coupling between the dark-matter particle and the darkish photon for a variety of dark-matter particle lots, ruling out each fashions. To acquire these outcomes, the NA64 experiment used a 100 GeV/c electron beam generated from protons interacting with a hard and fast goal. The collaboration utilized an lively beam dump and tried to reconstruct the hypothetical darkish photon, through each seen electron-positron pairs and lacking vitality for invisible decays.

Extra data:
NA62 collaboration, Seek for Ok⁺ decays into the π⁺e⁺e^–e⁺e^– closing state, arXiv (2023). DOI: 10.48550/arxiv.2307.04579

Journal data:
arXiv

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