Showing papers by "A. J. Noble published in 2006"
Laurentian University1, Queen's University2, University of Texas at Austin3, University of Pennsylvania4, Carleton University5, University of Guelph6, Lawrence Berkeley National Laboratory7, University of Oxford8, Los Alamos National Laboratory9, Goldman Sachs10, University of Washington11, Princeton University12, University of California, Irvine13, Massachusetts Institute of Technology14, Louisiana State University15, Brookhaven National Laboratory16, Hiroshima University17, University of British Columbia18, Fermilab19, University of Liverpool20, University of Chicago21, Lawrence Livermore National Laboratory22, Imperial College London23, Rutherford Appleton Laboratory24, University of Sussex25
TL;DR: In this article, a search for neutrinos from the hep reaction in the Sun and from the diffuse supernova neutrino background (DSNB) using data collected during the first operational phase of the Sudbury Neutrino Observatory, with an exposure of 0.65 ktons yr.
Abstract: A search has been made for neutrinos from the hep reaction in the Sun and from the diffuse supernova neutrino background (DSNB) using data collected during the first operational phase of the Sudbury Neutrino Observatory, with an exposure of 0.65 ktons yr. For the hep neutrino search, two events are observed in the effective electron energy range of 14.3 MeV < Teff < 20 MeV, where 3.1 background events are expected. After accounting for neutrino oscillations, an upper limit of 2.3 × 104 cm-2 s-1 at the 90% confidence level is inferred on the integral total flux of hep neutrinos. For DSNB neutrinos, no events are observed in the effective electron energy range of 21 MeV < Teff < 35 MeV, and, consequently, an upper limit on the νe component of the DSNB flux in the neutrino energy range of 22.9 MeV < Eν < 36.9 MeVof 70 cm-2 s-1 is inferred at the 90% confidence level. This is an improvement by a factor of 6.5 on the previous best upper limit on the hep neutrino flux and by 2 orders of magnitude on the previous upper limit on the νe component of the DSNB flux.
65 citations
19 Apr 2006
TL;DR: The PICASSO experiment is searching for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs) via their spin-dependent interactions with nuclei.
Abstract: The PICASSO experiment is searching for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs), in particular neutralinos (χ) via their spin‐dependent interactions with nuclei. The experiment is installed in the Sudbury Neutrino Observatory Laboratory at a depth of 2070 m (6000 mwe). PICASSO makes use of the superheated droplet technique with C4F10 as the active material, and searches for χ interactions on 19F. The results of these measurements are presented in terms of limits on the spin‐dependent χ‐proton and χ‐neutron cross sections. Limits on the effective χ‐proton and χ‐neutron coupling strengths ap and an are also reported. The results exclude new regions of the spin‐dependent χ‐nucleon interaction parameter space. The next phase of PICASSO is briefly discussed.
1 citations
TL;DR: Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.
Abstract: The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.
1 citations
TL;DR: The operation, calibration and data acquisition of the PICASSO experiment is discussed and also the ongoing work to increase the sensitivity and the active mass of the detectors is discussed.
Abstract: The PICASSO experiment investigates the presence and nature of dark matter in the Universe. The experiment is based on the detection of acoustic signals generated in explosive phase transitions induced by dark matter particles. This technique is an alternative more traditional detection technique like scintillation and ionisation, which are largely employed for dark matter search. One of the main advantages of this technique, besides its sensitivity to very low nuclear recoil energies (few keV), is its excellent background suppression features. A pilot experiment consisting of six superheated droplet detectors (40 g of active mass) is presently taking data at the Sudbury Neutrino Observatory (SNO) at a depth of 2000 m. We discuss the operation, calibration and data acquisition of the experiment and also the ongoing work to increase the sensitivity and the active mass of the detectors.
1 citations