Bulletin of the American Physical Society
3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009; Waikoloa, Hawaii
Session DJ: Neutrinos I |
Hide Abstracts |
Chair: Jason Detwiler, Lawrence Berkeley National Laboratory Room: Queens 4 |
Thursday, October 15, 2009 7:00PM - 7:15PM |
DJ.00001: First Production Detectors for the MAJORANA Experiment Victor Gehman The M{\sc ajorana} experiment is a next-generation search for 0$\nu\beta\beta$ in $^{76}$Ge. The M{\sc ajorana} collaboration is focused on fielding 60 kg of HPGe detectors as research and development (particularly the demonstration background levels) for a 1000-kilogram search. To this end, the M{\sc ajorana} collaboration has purchased the first eighteen detectors for its D{\sc emonstrator} phase from Canberra. The detectors are based on ``Broad Energy Germanium'' (BEGe) detectors, made from $^{\mbox{nat}}$Ge and are roughly 600 grams each. BEGes have low electronic noise, which leads to excellent energy resolution and sub-keV energy threshold. BEGes also require that electron-hole pairs drift over much longer distances than in semi-coaxial HPGe detectors. Long drift times lead to reliable separation of single-site signals from multi-site backgrounds with pulse shape analysis. The performance of BEGe detectors make them a powerful technology in the search for 0$\nu\beta\beta$. We plan to populate half of the D{\sc emonstrator} array with natural germanium detectors, and the other half with germanium enriched to 86\% in $^{76}$Ge. Here, we will present acceptance and characterization tests performed on these first eighteen detectors. In particular, we will focus on: energy resolution,leakage current, capacitance, charge collection and pulse shapes from single and multi-site events. [Preview Abstract] |
Thursday, October 15, 2009 7:15PM - 7:30PM |
DJ.00002: Status of the EXO-200 Experiment Liang Yang The Enriched Xenon Observatory (EXO) collaboration aims to perform the most sensitive search of the neutrinoless double beta decay process using Xe-136. The first phase of the experiment, EXO-200, uses 200 kg of liquid xenon with 80{\%} enrichment in Xe-136. The double beta decay of xenon is detected in an ultra-low background time projection chamber (TPC) by collecting both the scintillation light and the ionization charge. EXO-200 is currently undergoing final assembly and commissioning at the Waste Isolation Pilot Plant (WIPP) in New Mexico and Stanford in California, and will begin data taking at the end of 2009. With two years of running, EXO-200 is expected to be sensitive to half-lives of less than 6.4 x 10$^{25}$ years for neutrinoless double beta decay. [Preview Abstract] |
Thursday, October 15, 2009 7:30PM - 7:45PM |
DJ.00003: Large Area APDs in the EXO-200 neutrinoless double beta decay experiment Russell Neilson EXO (Enriched Xenon Observatory) is a program aimed at building a ton-class neutrinoless double beta decay detector using xenon enriched to 80\% in the isotope 136 as the source and detection medium. The first EXO experiment, known as EXO-200, is currently being commissioned in its underground location at the WIPP facility in Carlsbad, New Mexico. The centerpiece of EXO-200 is a liquid xenon TPC containing 200 kg of enriched xenon with simultaneous readout of ionization and scintallation. Scintallation photons are detected by 468 large area avalanche photodiodes (LAAPDs). This talk will briefly summarize the current status of EXO-200 and describe our study and characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector. [Preview Abstract] |
Thursday, October 15, 2009 7:45PM - 8:00PM |
DJ.00004: The Barium tagging system used at the EXO Enriched Xenon Observatory for Double Beta Decay research Axel Reimer Mueller One of the most interesting question in Neutrino Physics is that of the absolute scale of the neutrino mass. Neutrinoless Double Beta Decay provides an avenue for probing Majorana Neutrino masses below 10meV. The EXO experiment aims to detect Neutrinoless Double Beta Decay in Xenon-136, and to use ion trapping and laser spectroscopy techniques to tag the barium daughter of the double beta decay for the purpose of background elimination. This talk will be focused on ion extraction probe research, and the construction and use of a 70cm linear RF ion trap for the purpose of single ion fluorescence detection in a buffer gas environment. [Preview Abstract] |
Thursday, October 15, 2009 8:00PM - 8:15PM |
DJ.00005: The gas phase of EXO, status and perspectives Bassam Aharmim In my talk, I will be describing the R{\&}D programs conducted at different EXO institutions to develop detector technology and analysis tools that will lead to a sensitive search for the neutrinoless double beta decay of 136Xe in the gas phase. The prototypes being developed consist of pressure vessels able to operate at pressures up to 10 bar. Different readout systems (a cathode-anode drift filed system, CsI pads, Micromegas{\ldots}) are considered to detect the scintillation and ionization signals. Monte Carlo studies based on Geant 4, are used to help in optimizing the performance of the detectors. The prototypes will be used to evaluate and optimize the energy resolution and tracks reconstruction for background rejection. The longer-term goal is to scale up the technology to a multi-tonne detector. [Preview Abstract] |
Thursday, October 15, 2009 8:15PM - 8:30PM |
DJ.00006: Double-Beta Decay of $^{150}$Nd to Excited Final States Mary Kidd, James Esterline, Werner Tornow Determining the half life of two neutrino double-beta decay (2$\nu\beta\beta$) is important not only because it will be a background consideration for large-scale neutrinoless double-beta (0$\nu\beta\beta$) decay experiments, but also it is a valuable check for theoretical models. Models such as QRPA and the nuclear shell model can be used to calculate the nuclear matrix elements for 0$\nu\beta\beta$ decay, which would be necessary to obtain the effective electron neutrino mass from 0$\nu\beta\beta$ decay data. In QRPA models, the calculated matrix elements for transitions to the ground state and excited states depend in a different way on the so-called g$_{pp}$ parameter. Therefore, 2$\nu\beta\beta$ decay data to excited states are of special interest. Because SNO+ plans to use $^{150}$Nd as a nuclide in searches for 0$\nu\beta\beta$ decay, our goal is to measure the 2$\nu\beta\beta$ decay of $^{150}$Nd to the first excited 0$^+$ state in $^{150}$Sm. We search for this particular decay by detecting the 334 keV and 406.5 keV deexcitation gamma rays in coincidence. After 155 days of counting using a 50 g enriched $^{150}$Nd$_2$O$_3$ (43 g $^{150}$Nd) sample placed between two high-purity germanium detectors, we obtained a half-life of T$_{1/2}$=0.83$^{+0.75}_{-0.27}${\it(stat)}$\pm$0.04{\it(syst)}$\times$10$^{20}$ years. Here we update that result after collecting data for 12 months. Our apparatus is located at the Kimballton Underground Research Facility (KURF). This work was supported by the U.S. Department of Energy, Office of Nuclear Physics under grant number DE--FG02--97ER41033. [Preview Abstract] |
Thursday, October 15, 2009 8:30PM - 8:45PM |
DJ.00007: Double-beta decay Q values of $^{130}$Te, $^{128}$Te, and $^{120}$Te S.A. Caldwell, N.D. Scielzo, G. Savard, J.A. Clark, J. Van Schelt, C.M. Deibel, J. Fallis, S. Gulick, D. Lascar, A.F. Levand, G. Li, J. Mintz, E.B. Norman, K.S. Sharma, M. Sternberg, T. Sun Using the Canadian Penning Trap mass spectrometer we have measured $Q$ values for the double-beta decay processes with parent nuclei $^{120}$Te, $^{128}$Te, $^{130}$Te. These measurements are relevant to the search for neutrinoless double-beta decay ($0\nu \beta \beta$) at the COURE/CUORICINO experiment. If observed, $0\nu \beta \beta$ decay would imply that the electron neutrino is a massive Majorana particle and that lepton number is not universally conserved in nature. We provide our results and a discussion of their implications. [Preview Abstract] |
Thursday, October 15, 2009 8:45PM - 9:00PM |
DJ.00008: Study of the $^{150}$Sm(t,$^{3}$He) and $^{150}$Nd($^{3}$He,t) reactions with applications for the 0$\nu\beta\beta$ decay of $^{150}$Nd Carol Guess The NSCL charge-exchange group has ongoing programs to measure the spin-isospin response of nuclei. This talk will focus on measurements of the $^{150}$Sm(t,$^{3}$He)$^{150}$Pm* and $^{150}$Nd($^{3}$He,t)$^{150}$Pm* reactions, which are essential for studies of the neutrinoless double beta ($0\nu\beta\beta$) decay of $^{150}$Nd. $^{150}$Nd is one of the main candidates for $0\nu\beta\beta$ decay detection experiments. To design detectors for $0\nu\beta\beta$ decay and to extract information about the neutrino mass scale and hierarchy from resulting experimental data, accurate nuclear matrix elements are needed. Nuclear charge-exchange experiments can constrain theories used to predict these matrix elements by providing Gamow-Teller and higher order multipole transition strengths in the virtual intermediate nucleus. In addition to its applications for $0\nu\beta\beta$ decay, investigation of the spin-isospin response of heavy, deformed nuclei is important for future work on rare isotopes. [Preview Abstract] |
Thursday, October 15, 2009 9:00PM - 9:15PM |
DJ.00009: Shell model calculations of double-beta decay lifetimes of $^{48}$Ca Sabin Stoica, Andrei Neacsu, Mihai Horoi Recent results from neutrino oscillation experiments have convincingly demonstrated that neutrinos have mass and they can mix. The neutrinoless double beta ($0\nu\beta\beta$) decay is the most sensitive process to determine the absolute scale of the neutrino masses, and the only one that can distinguish whether neutrino is a Dirac or a Majorana particle. A key ingredient for extracting the absolute neutrino masses from $0\nu\beta\beta$ decay experiments is a precise knowledge of the nuclear matrix elements (NME) for this process. We developed a new strategy for computing the NME for the two-neutrino ($2\nu\beta\beta$) decay mode of Ca48, using GXPF1 and GXPF1A interactions. We reproduce the experimental value of the half-life for the g.s. to g.s. transitions, and we predict the lifetime for the g.s. to the first $2^+$ excited state. We also developed a new shell model approach for computing the NME for the $0\nu\beta\beta$ mode and used it in the case of $^{48}$Ca. The dependence of the results on short range correlations, the neutrino energy, and on the effective interaction will be discussed. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700