We report on a search for double beta decay of Formula omitted to the first Formula omitted excited state of Formula omitted using a Formula omitted exposure of Formula omitted collected with the ...CUORE-0 experiment. In this work we exploit different topologies of coincident events to search for both the neutrinoless and two-neutrino double beta decay modes. We find no evidence for either mode and place lower bounds on the half-lives: Formula omitted and Formula omitted ( Formula omitted). Combining our results with those obtained by the CUORICINO experiment, we achieve the most stringent constraints available for these processes: Formula omitted and Formula omitted ( Formula omitted).
We present, for the first time, the design of an instrument capable of measuring the high energy
(
>
60
MeV
)
muon-induced neutron flux deep underground. The instrument is based on applying the ...Gd-loaded liquid-scintillator technique to measure the rate of multiple low-energy neutron events produced in a Pb target and from this measurement to infer the rate of high energy neutron events. This unique signature allows both for efficient tagging of neutron multiplicity events as well as rejection of random gamma backgrounds so effectively that typical low-background techniques are not required. We present design studies based on Monte Carlo simulations that show that an apparatus consisting of a Pb target of 200
cm by 200
cm area by 60
cm thickness covered by a 60
cm thick Gd-loaded liquid scintillator (0.5% Gd content) detector could measure, at a depth of 2000
meters of water equivalent (m.w.e), a rate of
70
±
8
(stat) events/year with a background of less than 10 events/year. We discuss the relevance of this technique to measuring the muon-induced neutron background in searches for dark matter in the form of Weakly Interacting Massive Particles (WIMP). Based on these studies, we also discuss the benefits of using a neutron multiplicity meter as a component of active shielding in such experiments.
Here, we report a model that can be used to calculate superconducting transition temperature of a transition-edge sensor (TES), which is either a normal metal-superconductor-normal metal trilayer or ...a normal metal-superconductor bilayer. The model allows the TC estimation of a trilayer when the normal metals at the bottom and at the top are different. Furthermore, the model includes the spin flip time of the normal metals. We also use the TC calculations from this model for selected Ir-based trilayers and bilayers to help understand potential designs of low TC TESs. A Au/Ir/Au trilayer can have a low TC because the superconducting order parameter is reduced with normal metals at both sides. On the other hand, an Ir/Pt bilayer can have a low TC because the much larger electron density of states of Pt reduces the superconducting order parameter more effectively. Moreover, the spin flip scattering of paramagnetic Pt also contributes to the TC reduction.
Abstract We report on a search for double beta decay of $$^{130}\hbox {Te}$$ 130Te to the first $$0^{+}$$ 0+ excited state of $$^{130}\hbox {Xe}$$ 130Xe using a $$9.8\,\hbox {kg}\cdot \hbox {yr}$$ ...9.8kg·yr exposure of $$^{130}\hbox {Te}$$ 130Te collected with the CUORE-0 experiment. In this work we exploit different topologies of coincident events to search for both the neutrinoless and two-neutrino double beta decay modes. We find no evidence for either mode and place lower bounds on the half-lives: $$T^{0\nu }_{0^+_1}>7.9\cdot 10^{23}\hbox {yr}$$ T01+0ν>7.9·1023yr and $$T^{2\nu }_{0^+_1}>2.4\cdot 10^{23}\hbox {yr}$$ T01+2ν>2.4·1023yr ($$90\%\,\hbox {CL}$$ 90%CL ). Combining our results with those obtained by the CUORICINO experiment, we achieve the most stringent constraints available for these processes: $$T^{0\nu }_{0^+_1}>1.4\cdot 10^{24}\hbox {yr}$$ T01+0ν>1.4·1024yr and $$T^{2\nu }_{0^+_1}>2.5\cdot 10^{23}\hbox {yr}$$ T01+2ν>2.5·1023yr ($$90\%\,\hbox {CL}$$ 90%CL ).
Neutrinoless double beta decay (0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the ...status and outlook for bolometric 0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric0νββ experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (|mee|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. In conclusion, we highlight the main challenges and identify priorities for an R&D program addressing them.
We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using ...eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below {approx}10 GeV/c{sup 2}. This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c{sup 2} and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.
The SuperCDMS proposal for dark matter detection Akerib, D.S.; Attisha, M.J.; Bailey, C.N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2006, Letnik:
559, Številka:
2
Journal Article
Recenzirano
Presently the CDMS-II collaboration's Weakly Interacting Massive Particle (WIMP) search at the Soudan Underground Laboratory sets the most stringent exclusion limits of any WIMP cold dark matter ...direct-detection experiment. To extend our reach further, to WIMP-nucleon cross-sections in the range
10
-
46
-
10
-
44
cm
2
, we propose SuperCDMS, which would take advantage of a very deep site. One promising site is the recently approved SNOLab facility in Canada. In this paper we will present our overall program and focus on phase A of SuperCDMS.
We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October ...2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10{sup -44} cm{sup 2} (4.6x10{sup -44} cm{sup 2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c{sup 2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c{sup 2}, and significantly restricts the parameter space for some favored supersymmetric models.
We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of (130)Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and ...background level in the region of interest are 5.1±0.3 keV FWHM and 0.058±0.004(stat)±0.002(syst)counts/(keV kg yr), respectively. The median 90% C.L. lower-limit half-life sensitivity of the experiment is 2.9×10(24) yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of (130)Te and place a Bayesian lower bound on the decay half-life, T(1/2)(0ν)>2.7×10(24) yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of (130)Te from the Cuoricino experiment we obtain T(1/2)(0ν)>4.0×10(24) yr at 90% C.L. (Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, m(ββ)<270-760 meV.
Weakly Interacting Massive Particles (WIMPs) are a strong candidate for the Cold Dark Matter of the Universe. CDMS-II is a direct-search WIMP search experiment, operating at 50 mK and housed at the ...Soudan mine, Minnesota. The 250 gram Ge detectors utilize athermal phonon sensors where tungsten transition edge sensors are operated in negative electrothermal feedback. The search at Soudan is ongoing with an expected final reach of CDMS-II by the end of 2008 of a WIMP-nucleon cross-section sensitivity of 2.1 x10-44 cm2, at a WIMP mass of 60 GeV/c2. To proceed further, we have proposed the SuperCDMS program.
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