It is commonly conjectured that dark matter is a charge neutral fundamental particle. However, it may still have minute photon-mediated interactions through millicharge
or higher-order multipole ...interactions
, resulting from new physics at a high energy scale. Here we report a direct search for effective electromagnetic interactions between dark matter and xenon nuclei that produce a recoil of the latter from the PandaX-4T xenon-based detector
. Using this technique, the first constraint on the charge radius of dark matter is derived with the lowest excluded value of 1.9 × 10
fm
for a dark matter mass of 40 giga electron volts per speed of light in a vaccum squared (GeV/c
), more stringent than that for neutrinos by four orders of magnitude. Constraints on the magnitudes of millicharge, magnetic dipole moment, electric dipole moment and anapole moment are also improved substantially from previous searches
, with corresponding tightest upper limits of 2.6 × 10
e, 4.8 × 10
Bohr magnetons, 1.2 × 10
ecm and 1.6 × 10
cm
, respectively, for a dark matter mass of 20-40 GeV/c
.
We report results of a search for dark-matter-nucleon interactions via a dark mediator using optimized low-energy data from the PandaX-4T liquid xenon experiment. With the ionization-signal-only data ...and utilizing the Migdal effect, we set the most stringent limits on the cross section for dark matter masses ranging from 30 MeV/c^{2} to 2 GeV/c^{2}. Under the assumption that the dark mediator is a dark photon that decays into scalar dark matter pairs in the early Universe, we rule out significant parameter space of such thermal relic dark-matter model.
We report a search for light dark matter produced through the cascading decay of η mesons, which are created as a result of inelastic collisions between cosmic rays and Earth's atmosphere. We ...introduce a new and general framework, publicly accessible, designed to address boosted dark matter specifically, with which a full and dedicated simulation including both elastic and quasielastic processes of Earth attenuation effect on the dark matter particles arriving at the detector is performed. In the PandaX-4T commissioning data of 0.63 tonne·year exposure, no significant excess over background is observed. The first constraints on the interaction between light dark matter generated in the atmosphere and nucleus through a light scalar mediator are obtained. The lowest excluded cross section is set at 5.9×10^{-37} cm^{2} for a dark matter mass of 0.1 MeV/c^{2} and mediator mass of 300 MeV/c^{2}. The lowest upper limit of η to the dark matter decay branching ratio is 1.6×10^{-7}.
^{134}Xe is a candidate isotope for neutrinoless double beta decay (0νββ) search. In addition, the two-neutrino case (2νββ) allowed by the standard model of particle physics has not yet been ...observed. With the 656-kg natural xenon in the fiducial volume of the PandaX-4T detector, which contains 10.4% of ^{134}Xe, and its initial 94.9-day exposure, we have established the most stringent constraints on 2νββ and 0νββ of ^{134}Xe half-lives, with limits of 2.8×10^{22} yr and 3.0×10^{23} yr at 90% confidence level, respectively. The 2νββ (0νββ) limit surpasses the previously reported best result by a factor of 32 (2.7), highlighting the potential of large monolithic natural xenon detectors for double beta decay searches.
We report the first search for the elastic scatterings between cosmic-ray boosted sub-MeV dark matter and electrons in the PandaX-4T liquid xenon experiment. Sub-MeV dark matter particles can be ...accelerated by scattering with electrons in the cosmic rays and produce detectable electron recoil signals in the detector. Using the commissioning data from PandaX-4T of 0.63~tonne\(\cdot\)year exposure, we set new constraints on DM-electron scattering cross sections for DM masses ranging from 10~eV/\(c^2\) to 3~keV/\(c^2\).
In this letter, we report the dark matter search results from the
commissioning run and the first science run of the PandaX-4T experiment. A
blind analysis is carried out on the entire data set. The ...data processing is
improved compared to previous work, unifying the low-level signal
reconstruction in a wide energy range up to 120 keV. With a total exposure of
1.54 tonne$\cdot$year, no significant excess of nuclear recoil events is found.
The lowest 90% confidence level exclusion on the spin-independent cross section
is $1.6 \times 10^{-47} \mathrm{cm}^2$ at a dark matter mass of 40 GeV$/c^2$.
Our results represent the most stringent constraint for a dark matter mass
above 100 GeV$/c^2$.
