Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/$c^2$ to a few TeV/$c^2$. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a re-analysis of the first science run (SR1) of the LZ experiment, with an exposure of $0.9$ tonne$\times$year, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 10$^{17}$ GeV/$c^2$.
Upper limit on the WIMP-nucleon scattering cross section from the multiple-scatter analysis.
Upper limit on the WIMP-nucleus scattering cross section from the multiple-scatter analysis.
Upper limit on the WIMP-nucleon scattering cross section from the single-scatter analysis.
Following the first science results of the LUX-ZEPLIN (LZ) experiment, a dual-phase xenon time projection chamber operating from the Sanford Underground Research Facility in Lead, South Dakota, USA, we report the initial limits on a model-independent non-relativistic effective field theory describing the complete set of possible interactions of a weakly interacting massive particle (WIMP) with a nucleon. These results utilize the same 5.5 t fiducial mass and 60 live days of exposure collected for the LZ spin-independent and spin-dependent analyses while extending the upper limit of the energy region of interest by a factor of 7.5 to 270 keVnr. No significant excess in this high energy region is observed. Using a profile-likelihood ratio analysis, we report 90% confidence level exclusion limits on the coupling of each individual non-relativistic WIMP-nucleon operator for both elastic and inelastic interactions in the isoscalar and isovector bases.
Data points used in analysis in log_10(S2)-S1 space.
Data selection efficiency as a function of nuclear recoil energy
Isoscalar WIMP-nucleon elastic coupling limit for Operator 8
The LUX-ZEPLIN (LZ) experiment is a dark matter detector centered on a dual-phase xenon time projection chamber. We report searches for new physics appearing through few-keV-scale electron recoils, using the experiment's first exposure of 60 live days and a fiducial mass of 5.5t. The data are found to be consistent with a background-only hypothesis, and limits are set on models for new physics including solar axion electron coupling, solar neutrino magnetic moment and millicharge, and electron couplings to galactic axion-like particles and hidden photons. Similar limits are set on weakly interacting massive particle (WIMP) dark matter producing signals through ionized atomic states from the Migdal effect.
The SR1 data in the {S1c, log10S2c} space with respect to observed time. Top plot is first half of SR1 containing 178 of the final data set. Bottom plot is second half of SR1 containing 157 events.
Electronic Recoil (ER) detection efficiency evaluated as a function of simulated true ER energy [keVee]. The data contains ER detection efficiency for ROI of study.
The observed 90% C.L upper limit on effective neutrino magnetic moment (\mu_{\nu}[\mu_{B}]) in SR1. The data contains observed upper limit, median sensitivity and 1\sigma and 2\sigma sensitivity range.
The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60~live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c$^2$. The most stringent limit is set for spin-independent scattering at 36 GeV/c$^2$, rejecting cross sections above 9.2$\times 10^{-48}$ cm$^2$ at the 90% confidence level.
90% CL WIMP SI cross sections, including sensitivities
90% CL WIMP SDn cross sections, including sensitivities and nuclear structure uncertainties
90% CL WIMP SDp cross sections, including sensitivities and nuclear structure uncertainties
We perform a low-mass dark matter search using an exposure of 30\,kg$\times$yr with the XENON100 detector. By dropping the requirement of a scintillation signal and using only the ionization signal to determine the interaction energy, we lowered the energy threshold for detection to 0.7\,keV for nuclear recoils. No dark matter detection can be claimed because a complete background model cannot be constructed without a primary scintillation signal. Instead, we compute an upper limit on the WIMP-nucleon scattering cross section under the assumption that every event passing our selection criteria could be a signal event. Using an energy interval from 0.7\,keV to 9.1\,keV, we derive a limit on the spin-independent WIMP-nucleon cross section that excludes WIMPs with a mass of 6\,GeV/$c^2$ above $1.4 \times 10^{-41}$\,cm$^2$ at 90\% confidence level.
WIMP exclusion limit on the spin-independent WIMP-nucleon scattering cross section at 90% confidence level.
A search for muon neutrinos originating from dark matter annihilations in the Sun is performed using the data recorded by the ANTARES neutrino telescope from 2007 to 2012. In order to obtain the best possible sensitivities to dark matter signals, an optimisation of the event selection criteria is performed taking into account the background of atmospheric muons, atmospheric neutrinos and the energy spectra of the expected neutrino signals. No significant excess over the background is observed and $90\%$ C.L. upper limits on the neutrino flux, the spin--dependent and spin--independent WIMP-nucleon cross--sections are derived for WIMP masses ranging from $ \rm 50$ GeV to $\rm 5$ TeV for the annihilation channels $\rm WIMP + WIMP \to b \bar b, W^+ W^-$ and $\rm \tau^+ \tau^-$.
Upper limit on neutrino flux coming from the Sun for different annihiliation channels and WIMP masses. Limits for the $W^+W^-$ channel cannot be produced for WIMP masses below the mass of the $W$ boson.
Upper limit on spin-dependent cross-section for different annihiliation channels and WIMP masses. Limits for the $W^+W^-$ channel cannot be produced for WIMP masses below the mass of the $W$ boson.
Upper limit on spin-independent cross-section for different annihiliation channels and WIMP masses. Limits for the $W^+W^-$ channel cannot be produced for WIMP masses below the mass of the $W$ boson.
A comprehensive study on the atmospheric neutrino flux in the energy region from sub-GeV up to several TeV using the Super-Kamiokande water Cherenkov detector is presented in this paper. The energy and azimuthal spectra of the atmospheric ${\nu}_e+{\bar{\nu}}_e$ and ${\nu}_{\mu}+{\bar{\nu}}_{\mu}$ fluxes are measured. The energy spectra are obtained using an iterative unfolding method by combining various event topologies with differing energy responses. The azimuthal spectra depending on energy and zenith angle, and their modulation by geomagnetic effects, are also studied. A predicted east-west asymmetry is observed in both the ${\nu}_e$ and ${\nu}_{\mu}$ samples at 8.0 {\sigma} and 6.0 {\sigma} significance, respectively, and an indication that the asymmetry dipole angle changes depending on the zenith angle was seen at the 2.2 {\sigma} level. The measured energy and azimuthal spectra are consistent with the current flux models within the estimated systematic uncertainties. A study of the long-term correlation between the atmospheric neutrino flux and the solar magnetic activity cycle is also performed, and a weak indication of a correlation was seen at the 1.1 {\sigma} level, using SK I-IV data spanning a 20 year period. For particularly strong solar activity periods known as Forbush decreases, no theoretical prediction is available, but a deviation below the typical neutrino event rate is seen at the 2.4 {\sigma} level.
Electron neutrino flux measured by SK I-IV data. Error written in percentage including both statistical and systematic uncertainties.
Muon neutrino flux measured by SK I-IV data. Error written in percentage including both statistical and systematic uncertainties.
The ARGO-YBJ experiment is a full-coverage air shower detector located at the Yangbajing Cosmic Ray Observatory (Tibet, People's Republic of China, 4300 m a.s.l.). The high altitude, combined with the full-coverage technique, allows the detection of extensive air showers in a wide energy range and offer the possibility of measuring the cosmic ray proton plus helium spectrum down to the TeV region, where direct balloon/space-borne measurements are available. The detector has been in stable data taking in its full configuration from November 2007 to February 2013. In this paper the measurement of the cosmic ray proton plus helium energy spectrum is presented in the region 3-300 TeV by analyzing the full collected data sample. The resulting spectral index is $\gamma = -2.64 \pm 0.01$. These results demonstrate the possibility of performing an accurate measurement of the spectrum of light elements with a ground based air shower detector.
Proton plus helium flux measured at $5.0 \times 10^4$ GeV.
Light component energy spectrum measured by the ARGO-YBJ experiment by using the full 2008-2012 data sample in each energy bin.
We have measured the Coulomb dissociation of 8B into 7Be and proton at 254 MeV/nucleon using a large-acceptance focusing spectrometer. The astrophysical S17 factor for the 7Be(p,gamma)8B reaction at E{c.m.} = 0.25-2.78 MeV is deduced yielding S17(0)=20.6 \pm 1.2 (exp.) \pm 1.0 (theo.) eV-b. This result agrees with the presently adopted zero-energy S17 factor obtained in direct-reaction measurements and with the results of other Coulomb-dissociation studies performed at 46.5 and 51.2 MeV/nucleon.
S17(0) = E * SIG * EXP(CONST(C=ZOMMERFELD PARAMETER)). CONST(C=ZOMMERFELD PARAMETER) = 31.29*Z1*Z2*SQRT(M/E), where Z1 and Z2 are the nuclear charges of the interacting particles, M is the reduced mass, E is the center-of-mass energy. P BE7 reaction is extrapolation to inverse kinematics.
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