39 research outputs found
The Air Microwave Yield (AMY) experiment - A laboratory measurement of the microwave emission from extensive air showers
The AMY experiment aims to measure the microwave bremsstrahlung radiation
(MBR) emitted by air-showers secondary electrons accelerating in collisions
with neutral molecules of the atmosphere. The measurements are performed using
a beam of 510 MeV electrons at the Beam Test Facility (BTF) of Frascati INFN
National Laboratories. The goal of the AMY experiment is to measure in
laboratory conditions the yield and the spectrum of the GHz emission in the
frequency range between 1 and 20 GHz. The final purpose is to characterise the
process to be used in a next generation detectors of ultra-high energy cosmic
rays. A description of the experimental setup and the first results are
presented.Comment: 3 pages -- EPS-HEP'13 European Physical Society Conference on High
Energy Physics (July, 18-24, 2013) at Stockholm, Swede
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB
We present results of a dark matter search performed with a 0.6 kg day
exposure of the DAMIC experiment at the SNOLAB underground laboratory. We
measure the energy spectrum of ionization events in the bulk silicon of
charge-coupled devices down to a signal of 60 eV electron equivalent. The data
are consistent with radiogenic backgrounds, and constraints on the
spin-independent WIMP-nucleon elastic-scattering cross section are accordingly
placed. A region of parameter space relevant to the potential signal from the
CDMS-II Si experiment is excluded using the same target for the first time.
This result obtained with a limited exposure demonstrates the potential to
explore the low-mass WIMP region (<10 GeV/) of the upcoming DAMIC100, a
100 g detector currently being installed in SNOLAB.Comment: 11 pages, 11 figure
Nuclear Recoil Identification in a Scientific Charge-Coupled Device
Charge-coupled devices (CCDs) are a leading technology in direct dark matter
searches because of their eV-scale energy threshold and high spatial
resolution. The sensitivity of future CCD experiments could be enhanced by
distinguishing nuclear recoil signals from electronic recoil backgrounds in the
CCD silicon target. We present a technique for event-by-event identification of
nuclear recoils based on the spatial correlation between the primary ionization
event and the lattice defect left behind by the recoiling atom, later
identified as a localized excess of leakage current under thermal stimulation.
By irradiating a CCD with an AmBe neutron source, we demonstrate
identification efficiency for nuclear recoils with energies keV,
where the ionization events were confirmed to be nuclear recoils from topology.
The technique remains fully efficient down to 90 keV, decreasing to 50 at 8
keV, and reaching () at 1.5--3.5 keV. Irradiation with a Na
-ray source shows no evidence of defect generation by electronic
recoils, with the fraction of electronic recoils with energies keV that
are spatially correlated with defects .Comment: 9 pages, 7 figure
The DAMIC-M experiment: Status and first results
The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called âhidden sector.â A prototype, the Low Background Chamber (LBC), with 20g of low background Skipper CCDs, has been recently installed at Laboratoire Souterrain de Modane and is currently taking data. We will report the status of the DAMIC-M experiment and first results obtained with LBC commissioning data
First Constraints from DAMIC-M on Sub-GeV Dark-Matter Particles Interacting with Electrons
We report constraints on sub-GeV dark matter particles interacting with electrons from the first underground operation of DAMIC-M detectors. The search is performed with an integrated exposure of 85.23 g days, and exploits the subelectron charge resolution and low level of dark current of DAMIC-M charge-coupled devices (CCDs). Dark-matter-induced ionization signals above the detector dark current are searched for in CCD pixels with charge up to 7eâ. With this dataset we place limits on dark matter particles of mass between 0.53 and 1000ââMeV/c2, excluding unexplored regions of parameter space in the mass ranges [1.6,1000]ââMeV/c2 and [1.5,15.1]ââMeV/c2 for ultralight and heavy mediator interactions, respectively
Observation of inclined EeV air showers with the radio detector of the Pierre Auger Observatory
With the Auger Engineering Radio Array (AERA) of the Pierre AugerObservatory, we have observed the radio emission from 561 extensive air showerswith zenith angles between 60 and 84. In contrast to airshowers with more vertical incidence, these inclined air showers illuminatelarge ground areas of several km with radio signals detectable in the 30 to80\,MHz band. A comparison of the measured radio-signal amplitudes with MonteCarlo simulations of a subset of 50 events for which we reconstruct the energyusing the Auger surface detector shows agreement within the uncertainties ofthe current analysis. As expected for forward-beamed radio emission undergoingno significant absorption or scattering in the atmosphere, the area illuminatedby radio signals grows with the zenith angle of the air shower. Inclined airshowers with EeV energies are thus measurable with sparse radio-antenna arrayswith grid sizes of a km or more. This is particularly attractive as radiodetection provides direct access to the energy in the electromagnetic cascadeof an air shower, which in case of inclined air showers is not accessible byarrays of particle detectors on the ground
Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory
First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB
We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter Îș is competitive with constraints from solar emission, reaching a minimum value of at . These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses and the first demonstration of direct experimental sensitivity to ionization signals from dark matter interactions