6 research outputs found
A new direct detection electron scattering experiment to search for the X17 particle
A new electron scattering experiment (E12-21-003) to verify and understand
the nature of hidden sector particles, with particular emphasis on the
so-called X17 particle, has been approved at Jefferson Lab. The search for
these particles is motivated by new hidden sector models introduced to account
for a variety of experimental and observational puzzles: excess in
pairs observed in multiple nuclear transitions, the 4.2 disagreement
between experiments and the standard model prediction for the muon anomalous
magnetic moment, and the small-scale structure puzzle in cosmological
simulations. The aforementioned X17 particle has been hypothesized to account
for the excess in pairs observed from the Be M1, He M0, and,
most recently, C E1 nuclear transitions to their ground states observed
by the ATOMKI group. This experiment will use a high resolution electromagnetic
calorimeter to search for or set new limits on the production rate of the X17
and other hidden sector particles in the MeV mass range via their
decay (or decay with limited tracking). In these
models, the MeV mass range is particularly well-motivated and the
lower part of this range still remains unexplored. Our proposed direct
detection experiment will use a magnetic-spectrometer-free setup (the PRad
apparatus) to detect all three final state particles in the visible decay of a
hidden sector particle for an effective control of the background and will
cover the proposed mass range in a single setting. The use of the
well-demonstrated PRad setup allows for an essentially ready-to-run and
uniquely cost-effective search for hidden sector particles in the MeV
mass range with a sensitivity of 8.910 - 5.810 to
, the square of the kinetic mixing interaction constant between
hidden and visible sectors.Comment: 6 pages, 7 figures. arXiv admin note: substantial text overlap with
arXiv:2108.1327
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A Direct Detection Search for Hidden Sector New Particles in the 3-60 MeV Mass Range
In our quest to understand the nature of dark matter and discover its
non-gravitational interactions with ordinary matter, we propose an experiment
using a \pbo ~calorimeter to search for or set new limits on the production
rate of i) hidden sector particles in the MeV mass range via their
decay (or decay with limited tracking), and ii) the
hypothetical X17 particle, claimed in multiple recent experiments. The search
for these particles is motivated by new hidden sector models and dark matter
candidates introduced to account for a variety of experimental and
observational puzzles: the small-scale structure puzzle in cosmological
simulations, anomalies such as the 4.2 disagreement between experiments
and the standard model prediction for the muon anomalous magnetic moment, and
the excess of pairs from the Be M1 and He nuclear transitions
to their ground states observed by the ATOMKI group. In these models, the MeV mass range is particularly well-motivated and the lower part of this
range still remains unexplored. Our proposed direct detection experiment will
use a magnetic-spectrometer-free setup (the PRad apparatus) to detect all three
final state particles in the visible decay of a hidden sector particle allowing
for an effective control of the background and will cover the proposed mass
range in a single setting. The use of the well-demonstrated PRad setup allows
for an essentially ready-to-run and uniquely cost-effective search for hidden
sector particles in the MeV mass range with a sensitivity of
8.910 - 5.810 to , the square of the
kinetic mixing interaction constant between hidden and visible sectors. This
updated proposal includes our response to the PAC49 comments