Weakly Interacting Massive Particle

The thermal history of the universe before the epoch of nucleosynthesis is unknown. The maximum temperature in the radiation-dominated era, which we will refer to as the reheat temperature, may have been as low as 0.7 MeV. In this paper we show that a low reheat temperature has important implications for many topics in cosmology. We show that weakly interacting massive particles (WIMPs) may be produced even if the reheat temperature is much smaller than the freeze-out temperature of the WIMP, and that the dependence of the present abundance on the mass and the annihilation cross section of the WIMP differs drastically from familiar results. We revisit predictions of the relic abundance and resulting model constraints of supersymmetric dark matter, axions, massive neutrinos, and other dark matter candidates, nucleosynthesis constraints on decaying particles, and leptogenesis by decay of superheavy particles. We find that the allowed parameter space of supersymmetric models is altered, removing the usual bounds on the mass spectrum; the cosmological bound on massive neutrinos is drastically changed, ruling out Dirac (Majorana) neutrino masses mν only in the range 33 keV < ∼ mν < ∼ 6 (5) MeV, which is significantly smaller from the the standard disallowed range 94 eV < ∼ mν < ∼ 2 GeV (this implies that massive neutrinos may still play the role of either warm or cold dark matter); the cosmological upper bound on the Peccei-Quinn scale may be significantly increased to 10 16 GeV from the usually cited limit of about 10 12 GeV; and that efficient out-of-equilibrium GUT baryogenesis and/or leptogenesis can take place even if the reheat temperature is much smaller than the mass of the decaying superheavy particle.

Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of σAv ≃ 10 -22 cm 3 s -1 for WIMP masses above 1 TeV, assuming a monochromatic neutrino line spectrum.

Production of the neutron-induced isotope, 73 Ga, at the Davis Campus of the Sanford Underground Research Facility with the MAJORANA DEMONSTRATOR 1 PINGHAN CHU, Los Alamos National Laboratory, MAJORANA DEMONSTRATOR COLLABORATION -We report a study of the production of the neutron-induced isotope, 73 Ga, in the MAJORANA DEMONSTRATOR array at the underground Davis Campus of the Sanford Underground Research Facility 4850 ft level. This isotope has a half-life time of 4.86 hours and can be generated through interactions between fast neutrons and germanium isotopes. Using its unique decay signature, we have identified three candidate events of 73 Ga in the commissioning data of MAJORANA DEMONSTRATOR. Based on these three events, we estimate the corresponding neutron energy spectrum and the radioactive background generated by neutron-induced isotopes. The background from neutron-induced isotopes has been also calculated in the Region of Interest for 76 Ge neutrinoless double beta decays.

XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129Xe and 131Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of ∼10 GeV/c2-2 TeV/c2 as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo.

The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xe nuclei. A fiducial mass of 1000 kg, distributed in ten independent liquid xenon time projection chambers(LXeTPCs) will be used to probe the lowest interaction cross section predicted by SUSY models. The TPCs are operated in dual (liquid/gas) phase, to allow a measurement of nuclear recoils down to 16 keV energy, via simultaneous detection of the ionization, through secondary scintillation in the gas, and primary scintillation in the liquid. The distinct ratio of primary to secondary scintillation for nuclear recoils from WIMPs (or neutrons), and for electron recoils from background, is key to the event-by-event discrimination capability of XENON. A dual phase xenon prototype has been realized and is currently being tested, along with other prototypes dedicated to other measurements relevant to the XENON program. As part of the R&D phase, we will realize and move underground a first XENON module (XENON10) with at least 10 kg fiducial mass to measure the background rejection capability and to optimize the conditions for continuous and stable detector operation underground. We present some of the results from the ongoing R&D and summarize the expected performance of the 10 kg experiment, from Monte Carlo simulations. The main design features of the 100 kg detector unit(XENON100), with which we envisage to make up the 1 tonne sensitive mass of XENON1T will also be presented.

We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky γ-ray survey in the 20 MeV to >300 GeV energy range, provides a new opportunity to test particle dark matter models through the expected γ-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark

Submitted for the HAW14 Meeting of The American Physical Society Recombination in liquid xenon for low-energy recoils 1 LU WANG, DONGMING MEI, Univ of South Dakota, CUBED COLLABORATION-Detector response to low-energy recoils in sub-keV region is critical to detection of lowmass dark matter particles-WIMPS (Weakly interacting massive particles). The role of electron-ion recombination is important to the interpretation of the relation between ionization yield and scintillation yield, which are in general anti-correlated. Recent experimental results show that ionization yield increases down to keV range. This phenomenon contradicts general understanding for low energy recoils in the keV range in which direct excitation dominates. The explanation is that recombination becomes much less efficient when the track length is smaller than the thermalization distance of electrons. However, recombination rate is also proportional to ionization density, which is very high for keV recoils. To understand how recombination rate behaves for keV recoils, we calculated both initial recombination rate and volume recombination rate for keV recoils in liquid xenon. In this paper, we show the results of the calculated recombination rate as a function of recoil energy for both electronic recoils and nuclear recoils. 1 DE-FG02-10ER46709 and the state of South Dakota

We present the first experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of $1.4~\times~10^{4}~\text{kg}\cdot~\text{days}$ of fiducial exposure allows 90% CL upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of $\sigma_n~=~9.4~\times~10^{-41}~\text{cm}^2$ ($\sigma_p~=~2.9~\times~10^{-39}~\text{cm}^2$) at 33 GeV/c$^2$. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

The first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in ...

We report here the results of a non-relativistic Effective Field Theory (EFT) WIMP search analysis using LUX data. We build upon previous LUX analyses by extending the search window to include nuclear recoil energies up to ∼180 keVnr, requiring a reassessment of data quality criteria and background models. In order to use an unbinned Profile Likelihood statistical framework, the development of new analysis techniques to account for higher-energy backgrounds was required. With a 3.14×10 4 kg•day exposure using data collected between 2014 and 2016, we find our data is compatible with the background expectation and set 90% C.L. exclusion limits on non-relativistic EFT WIMP-nucleon couplings, improving upon previous LUX results and providing constraints on a EFT WIMP interactions using the {neutron,proton} interaction basis. Additionally, we report exclusion limits on inelastic EFT WIMP-isoscalar recoils that are competitive and world-leading for several interaction operators.

Modeling electric fields inside the LUX detector 3 2.1 LUX 3D model geometry 3 2.2 Electric fields modeling 4 2.3 Modeling charges in the LUX detector 6 2.4 Alternative explanations for the field distortion 8 3 Modeling detector observables 9 3.1 WS2013 modeling results 9 3.2 Alternative determination of electric field magnitude using NEST 11 4 Time-dependence of electric fields during WS2014-16 13 4.1 Charge evolution 13 4.2 Electric fields in WS2014-16 analysis 14

We report results from an extensive set of measurements of the β-decay response in liquid xenon. These measurements are derived from high-statistics calibration data from injected sources of both 3 H and 14 C in the LUX detector. The mean light-to-charge ratio is reported for 13 electric field values ranging from 43 to 491 V/cm, and for energies ranging from 1.5 to 145 keV.

XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spindependent WIMP-nucleon interactions with 129 Xe and 131 Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of 10 GeV=c 2 -2 TeV=c 2 as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo.

We report the dark matter search results obtained using the full 132 ton·day exposure of the PandaX-II experiment, including all data from March 2016 to August 2018. No significant excess of events is identified above the expected background. Upper limits are set on the spin-independent dark matter-nucleon interactions. The lowest 90% confidence level exclusion on the spin-independent cross section is 2.2 × 10−46 cm2 at a WIMP mass of 30 GeV/c2.

New constraints are presented on the spin-dependent weakly-interacting-massive-particle–- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10^{4}  kg day. Assuming a standard axial-vector spin-dependent WIMP interaction with ^{129}Xe and ^{131}Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10  GeV/c^{2} are set in all dark matter direct detection experiments. The minimum upper limit of 4.1×10^{-41}  cm^{2} at 90% confidence level is obtained for a WIMP mass of 40  GeV/c^{2}. This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

We present the results of a search for WIMPs from the commissioning run of the PandaX-II experiment located at the China Jinping underground Laboratory. A WIMP search data set with an exposure of 306×19.1 kg-day was taken, while its dominant 85 Kr background was used as the electron recoil calibration. No WIMP candidates are identified, and a 90% upper limit is set on the spin-independent elastic WIMP-nucleon cross section with a lowest excluded cross section of 2.97×10 −45 cm 2 at a WIMP mass of 44.7 GeV/c 2 .

In this 2001 status report of the MACRO experiment, results are presented on atmospheric neutrinos and neutrino oscillations, high energy neutrino astronomy, searches for WIMPs, search for low energy stellar gravitational collapse neutrinos, stringent upper limits on GUT magnetic monopoles, nuclearites and lightly ionizing particles, high energy downgoing muons, primary cosmic ray composition and shadowing of primary cosmic rays by the Moon and the Sun.

The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, we present first dark matter results from the analysis of 11.17 live days of non-blind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the pre-defined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross-sections above 3.4 × 10 −44 cm 2 for 55 GeV/c 2 WIMPs at 90% confidence level. Below 20 GeV/c 2 , this result constrains the interpretation of the CoGeNT and DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.

We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as ultra-low background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic WIMP-nucleon scattering cross-sections above 7.0 × 10 −45 cm 2 for a WIMP mass of 50 GeV/c 2 at 90% confidence level.

Many experiments that aim at the direct detection of dark matter are able to distinguish a dominant background from the expected feeble signals, based on some measured discrimination parameter. We develop a statistical model for such experiments using the profile likelihood ratio as a test statistic in a frequentist approach. We take data from calibrations as control measurements for signal and background, and the method allows the inclusion of data from Monte Carlo simulations. Systematic detector uncertainties, such as uncertainties in the energy scale, as well as astrophysical uncertainties, are included in the model. The statistical model can be used to either set an exclusion limit or to quantify a discovery claim, and the results are derived with the proper treatment of statistical and systematic uncertainties. We apply the model to the first data release of the XENON100 experiment, which allows one to extract additional information from the data, and place stronger limits on the spin-independent elastic weakly interacting massive particles nucleon scattering cross section. In particular, we derive a single limit, including all relevant systematic uncertainties, with a minimum of 2.4×10-44 cm2 for weakly interacting massive particles with a mass of 50 GeV/c2.

The XENON100 experiment, located at the Laboratori Nazionali del Gran Sasso (LNGS), aims to directly detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off xenon nuclei. We present a comprehensive study of the predicted electronic recoil background coming from radioactive decays inside the detector and shield materials, and intrinsic radioactivity in the liquid xenon. Based on GEANT4 Monte Carlo simulations using a detailed geometry together with the measured radioactivity of all detector components, we predict an electronic recoil background in the WIMP-search energy range and 30 kg fiducial mass of less than 10 −2 events•kg −1 •day −1 •keV −1 , consistent with the experiment's design goal. The predicted background spectrum is in very good agreement with the data taken during the commissioning of the detector in Fall 2009.

High energy gamma ray astronomy is now a well established field and several sources have been discovered in the region from a few GeV up to several TeV. If sources involving hadronic processes exist, the production of photons would be accompanied by neutrinos too. Other possible neutrino sources could be related to the annihilation of WIMPs at the center of galaxies with black holes. We present the results of a search for point-like sources using 1100 upward-going muons produced by neutrino interactions in the rock below and inside the MACRO detector in the underground Gran Sasso Laboratory. These data show no evidence for a possible neutrino point-like source or for possible correlations between gamma ray bursts and neutrinos. They have been used to set flux upper limits for candidate point-like sources which are in the range 10 −14 − 10 −15 cm −2 s −1 .

Many dark matter interaction types lead to annihilation processes which suffer from p-wave suppression or helicity suppression, rendering them subdominant to unsuppressed s-wave processes. We demonstrate that the natural inclusion of dark initial state radiation can open an unsuppressed s-wave annihilation channel, and thus provide the dominant dark matter annihilation process for particular interaction types. We illustrate this effect with the bremsstrahlung of a dark spin-0 or dark spin-1 particle from fermionic dark matter, χχ → f f φ or f f Z. The dark initial state radiation process, despite having a 3-body final state, proceeds at the same order in the new physics scale Λ as the annihilation to the 2-body final state χχ → f f. This opens an unsuppressed s-wave at lower order in Λ than the well-studied lifting of helicity suppression via Standard Model final state radiation, or virtual internal bremsstrahlung. This dark bremsstrahlung process should influence LHC and indirect detection searches for dark matter.

Many dark matter interaction types lead to annihilation processes which suffer from p-wave suppression or helicity suppression, rendering them subdominant to unsuppressed s-wave processes. We demonstrate that the natural inclusion of dark initial state radiation can open an unsuppressed s-wave annihilation channel, and thus provide the dominant dark matter annihilation process for particular interaction types. We illustrate this effect with the bremsstrahlung of a dark spin-0 or dark spin-1 particle from fermionic dark matter, χχ → f f φ or f f Z. The dark initial state radiation process, despite having a 3-body final state, proceeds at the same order in the new physics scale Λ as the annihilation to the 2-body final state χχ → f f. This opens an unsuppressed s-wave at lower order in Λ than the well-studied lifting of helicity suppression via Standard Model final state radiation, or virtual internal bremsstrahlung. This dark bremsstrahlung process should influence LHC and indirect detection searches for dark matter.

In the past decades, numerous experiments have emerged to unveil the nature of dark matter, one of the most discussed open questions in modern particle physics. Among them, the CRESST experiment, located at the Laboratori Nazionali del Gran Sasso, operates scintillating crystals as cryogenic phonon detectors. In this work, we present first results from the operation of two detector modules which both have 10.46 g LiAlO 2 targets in CRESST-III. The lithium contents in the crystal are 6 Li, with an odd number of protons and neutrons, and 7 Li, with an odd number of protons. By considering both isotopes of lithium and 27 Al, we set the currently strongest cross section upper limits on spin-dependent interaction of dark matter with protons and neutrons for the mass region between 0.25 and 1.5 GeV/c 2 .

First results from a Dark Matter search with liquid Argon at 87 K in the Gran Sasso Underground Laboratory. P. Benetti (a) , R. Acciarri (f) , F. Adamo (b) , B. Baibussinov (g) , M. Baldo-Ceolin (g) , M. Belluco (a) , F. Calaprice (d) , E. Calligarich (a) , M. Cambiaghi (a) , F. Carbonara (b) , F. Cavanna (f) , S. Centro (g) , A.G. Cocco (b) , F. Di Pompeo (f) , N. Ferrari (c) (†) , G. Fiorillo (b) , C. Galbiati (d) , V. Gallo (b) , L. Grandi (a) , A. Ianni (c) , G. Mangano (b) , G. Meng (g) , C. Montanari (a) , O. Palamara (c) , L. Pandola (c) , F. Pietropaolo (g) , G.L. Raselli (a) , M. Rossella (a) , C. Rubbia (a)(+) , A. M. Szelc (e) , S. Ventura (g) and C. Vignoli (a)

95.35.+d, 98.35.-a, 95.75.-z abstract Terrestrial dark matter detection experiments probe the velocity-space distribution of dark matter particles in the vicinity of the Earth. We present a novel method, to be used in conjunction with standard cosmological simulations of hierarchical clustering, that allows one to extract a truly local velocity-space distribution in exquisite detail. Preliminary results suggest a new picture for this distribution which is decidedly non-Maxwellian but instead is characterized by randomly positioned peaks in velocity space. We discuss the implications of these results for both WIMP and axion detection experiments.

The HESS array of Cherenkov telescopes has performed, from 2004 to 2007, a survey of the inner galactic plane at photon energies above 100 GeV. About 400 hours of data have been accumulated in the region between À30 and þ60 degrees in galactic longitude, and between À3 and þ3 degrees in galactic latitude. Assuming that dark matter is composed of weakly interacting massive particles, we calculate here the HESS sensitivity map for dark matter annihilations, and derive the first experimental constraints on the (''minispikes'') scenario, in which a gamma-ray signal arises from dark matter annihilation around intermediate mass black holes. The data exclude the proposed scenario at a 90% confidence level for dark matter particles with velocity-weighted annihilation cross section v above 10 À28 cm 3 s À1 and mass between 800 GeV and 10 TeV.

The CRESST experiment observes an unexplained excess of events at low energies. In the current CRESST-III data-taking campaign we are operating detector modules with different designs to narrow down the possible explanations. In this work, we show first observations of the ongoing measurement, focusing on the comparison of time, energy and temperature dependence of the excess in several detectors. These exclude dark matter, radioactive backgrounds and intrinsic sources related to the crystal bulk as a major contribution.

The CRESST experiment employs cryogenic calorimeters for the sensitive measurement of nuclear recoils induced by dark matter particles. The recorded signals need to undergo a careful cleaning process to avoid wrongly reconstructed recoil energies caused by pile-up and read-out artefacts. We frame this process as a time series classification task and propose to automate it with neural networks. With a data set of over one million labeled records from 68 detectors, recorded between 2013 and 2019 by CRESST, we test the capability of four commonly used neural network architectures to learn the data cleaning task. Our best performing model achieves a balanced accuracy of 0.932 on our test set. We show on an exemplary detector that about half of the wrongly predicted events are in fact wrongly labeled events, and a large share of the remaining ones have a context-dependent ground truth. We furthermore evaluate the recall and selectivity of our classifiers with simulated data. The results ...

In the past decades, numerous experiments have emerged to unveil the nature of dark matter, one of the most discussed open questions in modern particle physics. Among them, the CRESST experiment, located at the Laboratori Nazionali del Gran Sasso, operates scintillating crystals as cryogenic phonon detectors. In this work, we present first results from the operation of two detector modules which both have 10.46 g LiAlO 2 targets in CRESST-III. The lithium contents in the crystal are 6 Li, with an odd number of protons and neutrons, and 7 Li, with an odd number of protons. By considering both isotopes of lithium and 27 Al, we set the currently strongest cross section upper limits on spin-dependent interaction of dark matter with protons and neutrons for the mass region between 0.25 and 1.5 GeV/c 2 .

New constraints are presented on the spin-dependent WIMP-nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10 4 kg-days. Assuming a standard axial-vector spin-dependent WIMP interaction with 129 Xe and 131 Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c 2 are set in all dark matter direct detection experiments. The minimum upper limit of 4.1 × 10 −41 cm 2 at 90% confidence level is obtained for a WIMP mass of 40 GeV/c 2. This represents more than a factor of two improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

New constraints are presented on the spin-dependent WIMP-nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10 4 kg-days. Assuming a standard axial-vector spin-dependent WIMP interaction with 129 Xe and 131 Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c 2 are set in all dark matter direct detection experiments. The minimum upper limit of 4.1 × 10 −41 cm 2 at 90% confidence level is obtained for a WIMP mass of 40 GeV/c 2. This represents more than a factor of two improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

New constraints are presented on the spin-dependent WIMP-nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10 4 kg-days. Assuming a standard axial-vector spin-dependent WIMP interaction with 129 Xe and 131 Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c 2 are set in all dark matter direct detection experiments. The minimum upper limit of 4.1 × 10 −41 cm 2 at 90% confidence level is obtained for a WIMP mass of 40 GeV/c 2. This represents more than a factor of two improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

We present the results of a search for WIMPs from the commissioning run of the PandaX-II experiment located at the China Jinping underground Laboratory. A WIMP search data set with an exposure of 306×19.1 kg-day was taken, while its dominant 85 Kr background was used as the electron recoil calibration. No WIMP candidates are identified, and a 90% upper limit is set on the spin-independent elastic WIMP-nucleon cross section with a lowest excluded cross section of 2.97×10 −45 cm 2 at a WIMP mass of 44.7 GeV/c 2 .

High energy gamma ray astronomy is now a well established field and several sources have been discovered in the region from a few GeV up to several TeV. If sources involving hadronic processes exist, the production of photons would be accompanied by neutrinos too. Other possible neutrino sources could be related to the annihilation of WIMPs at the center of galaxies with black holes. We present the results of a search for point-like sources using 1100 upward-going muons produced by neutrino interactions in the rock below and inside the MACRO detector in the underground Gran Sasso Laboratory. These data show no evidence for a possible neutrino point-like source or for possible correlations between gamma ray bursts and neutrinos. They have been used to set flux upper limits for candidate point-like sources which are in the range 10 −14 − 10 −15 cm −2 s −1 .

The Cryogenic Dark Matter Search (CDMS) uses low-temperature Ge and Si detectors to search for Weakly Interacting Massive Particles (WIMPs) via their elastic-scattering interaction with atomic nuclei while discriminating against interactions of background particles. CDMS data from 1998 and 1999 with a relaxed fiducial-volume cut (resulting in 15.8 kg-days exposure on Ge) are consistent with an earlier analysis with a more restrictive fiducial-volume cut. Twenty-three WIMP candidate events are observed, but these events are consistent with a background from neutrons. Resulting limits on the spin-independent WIMP-nucleon elastic-scattering crosssection are lower than those of any other experiment for WIMPs with masses between 10-70 GeV c −2. Under the assumptions of standard WIMP interactions and a standard halo, the results are incompatible with the annual-modulation signal of DAMA at 99.99% CL in the asymptotic limit.