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Neutron Distributions Measured with Beta Decays and Photographic Emulsions

Description: Abstract: "A method has been developed for observing the "fine structure" of neutron flux distribution. Difference in neutron flux in regions a half a millimeter apart have been measured. Examples in which this resolution has been useful are given. In the case of a polythene ball, three-fourths of an inch in diameter, in the center of the Little Eva reactor, the effective neutron flux varies 75% of the unperturbed value between two readings a tenth of an inch apart."
Date: 1956
Creator: Young, Dwight S.
Partner: UNT Libraries Government Documents Department

Neutrinoless Double Beta Decay in Light of SNO Salt Data

Description: In the SNO data from its salt run, probably the most significant result is the consistency with the previous results without assuming the 8B energy spectrum. In addition, they have excluded the maximal mixing at a very high confidence level. This has an important implication on the double beta decay experiments. For the inverted or degenerate mass spectrum, we find bar<m_nu>_ee bar> 0.013 eV at 95percent CL, and the next generation experiments can discriminate Majorana and Dirac neutrinos if the invertedor degenerate mass spectrum will be confirmed by the improvements in cosmology, tritium data beta decay, or long-baseline oscillation experiments.
Date: September 11, 2003
Creator: Murayama, Hitoshi & Pena-Garay, Carlos
Partner: UNT Libraries Government Documents Department

The Beta-Neutrino Correlation in Sodium-21 and Other Nuclei

Description: We have measured the mbox beta - nu correlation coefficient,a_beta nu, in 21Na using a laser-trapped sample. We measure the energyspectrum of the recoil nuclei by measuring their time-of-flight incoincidence with the atomic electrons shaken off in beta decay. Highdetectionefficiency of these low-energy electrons allows good countingstatistics, even with low trap density, which suppresses thephotoassociation of molecular sodium, which can cause a large systematicerror. Our measurement, with a 1 percent fractional uncertainty, agreeswith the Standard Model prediction but disagrees with our previousmeasurement which was susceptible to error introduced by molecularsodium. We summarize precise measurements of a_ beta nu and theirconsequences for searches for Beyond Standard Model scalar and tensorcurrent couplings.
Date: January 16, 2008
Creator: Vetter, Paul A.; Abo-Shaeer, Jamil; Freedman, Stuart J. & Maruyama, Reina
Partner: UNT Libraries Government Documents Department

Muon-induced backgrounds in the CUORICINO experiment

Description: To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO siteand operated during the final 3 months of the experiment. From these measurements, an upper limit of 0.0021 counts/(keV.kg.yr) (95percent c.l.) was obtained on the cosmicray induced background in the neutrinoless double beta decay region of interest. The measurements were also compared to Geant4 simulations.
Date: April 15, 2010
Creator: Andreotti, E.; Arnaboldi, C.; Avignone III, F. T.; Balata, M.; Bandac, I.; Barucci, M. et al.
Partner: UNT Libraries Government Documents Department

Coexistence of a weakly-deformed band in a strongly-deformednucleus

Description: A weakly-deformed band J{sup {pi}} (E{sub x} keV) 0+ (1182), 2+ (1418), 4+ (1701) is identified in the strongly-deformed nucleus, {sup 154}Gd. Detailed {gamma}-ray spectroscopy following the beta decays of {sup 154}Eu (J = 3), {sup 154g,m1,m2}Tb (J = 0, 3, 7) are used to establish this structure. The structure is explained in terms of a pairing isomer which results from the {nu}[505] {up_arrow} Nilsson intruder orbital.
Date: October 27, 2002
Creator: Kulp, W.D.; Wood, J.L.; Krane, K.S.; Loats, J.; Schmelzenbach,P.; Stapels, C.J. et al.
Partner: UNT Libraries Government Documents Department

A Proposed Experimental Test of the Neutrino Theory

Description: The experiment outlined in this proposal has the possibility of giving an answer to the important question, 'Does the neutrino exist'? It is unfortunate that at the present time, there is no convincing experimental that neutrinos exist. Two recent articles review the status of various experiments which could give information about neutrinos. In general, these experiments give results in agreement with the predictions of beta decay theory. But actually, if even the most complete of the 'recoil type' experiments could be performed satisfactorily, all that could be concluded would be the following: the energy and momentum relationships in beta decay are consistent with the theory that the known energy deficit is carried away by a single particle. But to emphasize the fact that this would not constitute a proof of the real existence of that particle, the following quotations from the review articles should be noted. Crane says, 'All of the evidence about the neutrino is, as already pointed out, indirect in character since neutrinos have not yet been caught after leaving the nucleus. It can, of course, be argued on very general grounds that, if energy is not conserved between nucleus and electron, momentum should not be expected to be conserved either, and in consequence of this, it has often been remarked that the recoiled experiments add nothing that is really new to their knowledge'. Allen concludes his article by saying, 'Practically all the experimental evidence indicates that there is an apparent non-conservation of momentum in the beta decay process, and that the neutrino hypothesis is at least one explanation of the missing momentum'.
Date: April 18, 1949
Creator: Alvarez, Luis W.
Partner: UNT Libraries Government Documents Department

A New Limit on Time-Reversal Violation in Beta Decay

Description: We report the results of an improved determination of the triple correlation DP {center_dot} (p{sub e} x p{sub v}) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the Standard Model. Our result is D = (-0.96 {+-} 1.89(stat) {+-} 1.01(sys)) x 10{sup -4}. The corresponding phase between g{sub A} and g{sub V} is {phi}{sub AV} = 180.013{sup o} {+-} 0.028{sup o} (68% confidence level). This result represents the most sensitive measurement of D in nuclear beta decay.
Date: April 26, 2011
Creator: Mumm, H P; Chupp, T E; Cooper, R L; Coulter, K P; Freedman, S J; Fujikawa, B K et al.
Partner: UNT Libraries Government Documents Department

On Double-Beta Decay Half-Life Time Systematics

Description: Recommended 2{beta}(2{nu}) half-life values and their systematics were analyzed in the framework of a simple empirical approach. T{sub 1/2}{sup 2{nu}} {approx} 1/E{sup 8} trend has been observed for {sup 128,130}Te recommended values. This trend was used to predict T{sub 1/2}{sup 2{nu}} for all isotopes of interest. Current results were compared with other theoretical and experimental works.
Date: April 14, 2010
Creator: Pritychenko, B.
Partner: UNT Libraries Government Documents Department

Time-reversal violation in beta decay

Description: At present there is no unambigous direct evidence for time-reversal (T) violation in the fundamental interactions. But T-violation is intimately connected with CP-violation by the CPT theorem. A stringent bound on possible violation of CPT invariance comes from the properties of K{sup 0} - {bar K}{sup 0} mixing [I]. In the following we shall assume that CPT violating interactions, if present, can be neglected, and use the terms 'T-violation' and 'CP-violation' interchangably.
Date: January 1, 2003
Creator: Herczeg, P. (Peter)
Partner: UNT Libraries Government Documents Department

Electrical Signal Path Study and Component Assay for the MAJORANA N-Type Segmented Contact Detector

Description: The purpose of the present electrical signal path study is to explore the various issues related to the deployment of highly-segmented low-background Ge detectors for the MAJORANA double-beta decay experiment. A significant challenge is to simultaneously satisfy competing requirements for the mechanical design, electrical readout performance, and radiopurity specifications from the MAJORANA project. Common to all rare search experiments, there is a very stringent limit on the acceptable radioactivity level of all the electronics components involved. Some of the findings are summarized in this report.
Date: February 24, 2009
Creator: Amman, Mark; Bergevin, Marc; Chan, Yuen-Dat; Detwiler, Jason A.; Fujikawa, Brian .; Lesko, Kevin T. et al.
Partner: UNT Libraries Government Documents Department

A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment

Description: CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2{nu}{beta}{beta}). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO{sub 2} crystals arranged in a tower and operated at a temperature of #24;10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors. The experiment included 4 enriched crystals, 2 enriched with {sup 130}Te and 2 with {sup 128}Te, in order to aid in the measurement of the 2{nu}{beta}{beta} rate. The enriched crystals contained a total of #24;350 g {sup 130}Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130- enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2{nu}{beta}{beta} half-life was measured to be T{sup 2{nu}}{sub 1/2} = [9.81{+-} #6;0.96(stat){+-} 0.49(syst)]#2;x10{sup 20} y.
Date: November 3, 2011
Creator: Kogler, Laura
Partner: UNT Libraries Government Documents Department

Optimization of the Transport Shield for Neutrinoless Double Beta-decay Enriched Germanium

Description: This document presents results of an investigation of the material and geometry choice for the transport shield of germanium, the active detector material used in 76Ge neutrinoless double beta decay searches. The objective of this work is to select the optimal material and geometry to minimize cosmogenic production of radioactive isotopes in the germanium material. The design of such a shield is based on the calculation of the cosmogenic production rate of isotopes that are known to cause interfering backgrounds in 76Ge neutrinoless double beta decay searches.
Date: April 15, 2012
Creator: Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Orrell, John L.; Reid, Douglas J. & Fast, James E.
Partner: UNT Libraries Government Documents Department

Measurement of the beta-neutrino correlation of sodium-21 usingshakeoff electrons

Description: The beta-neutrino correlation coefficient, a_beta nu, ismeasured in 21Na by detecting the time-of-flight of the recoil nucleusdetected in coincidence with the atomic electrons shaken off in betadecay. The sample of 21Na is confined in a magneto-optic trap. Highdetection efficiency allows low trap density, which suppresses thephotoassociation of molecular sodium, which can cause a large systematicerror. Suppressing the fraction of trapped atoms in the excited stateusing a dark trap also reduces the photoassociation process, and datataken with this technique are consistent. The main remaining systematicuncertainties come from the measurement of the position and size of theatom trap, and the subtraction of background. We find mbox a_betanu=0.5502(60), in agreement with the Standard Model prediction of mboxa_beta nu=0.553(2), and disagreeing with a previous measurement which wassusceptible to an error introduced by the presence of molecularsodium.
Date: January 16, 2007
Creator: Vetter, Paul A.; Abo-Shaeer, Jamil R.; Freedman, Stuart J. & Maruyama, Reina
Partner: UNT Libraries Government Documents Department

Half-life of 14O

Description: We have measured the half-life of 14O, a superallowed (0+\rightarrow 0+) \beta decay isotope. The 14O was produced by the12C(3He,n)14O reaction using a carbon aerogel target. A low-energy ionbeam of 14O was mass separated and implanted in a thin beryllium foil.The beta particles were counted with plastic scintillator detectors. Wefind \tau 1/2 = 70.696 +- 0.037\sigma. This result is 2.0\sigma higherthan an average value from six earlier experiments, but agrees moreclosely with the most recent previous measurment.
Date: January 11, 2006
Creator: Burke, Jason T.; Vetter, Paul A.; Freedman, Stuart J.; Fujikawa,Brian K. & Winter, Wesley T.
Partner: UNT Libraries Government Documents Department

2007 Nuclear Data Review

Description: The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very heavy elements (trans-meitnerium elements) are discussed and tabulated. The first observation of the radioactive decay mode of the free neutron is discussed. New measurements that have expanded the neutron drip line for magnesium and aluminum are discussed. Data on recent neutron cross-section and resonance integral measurements are also discussed.
Date: May 5, 2008
Creator: Holden,N.E.
Partner: UNT Libraries Government Documents Department


Description: Summary and Conclusions - It was shown that segmentation and pulse-shape discrimination can improve the discovery sensitivity of a next-gen 0vBB-decay experiment by 90%. - However, when practical aspects are considered (such as instrumenting each segment with front-end electronics), the discovery sensitivity is decreased by 19%. - This has extremely important consequences to proposed next-gen experiments since the two active collaborations have strongly advocated the use of segmented detectors for all or part of the experiment. - New germanium detector technology, currently under development, has demonstrated excellent multi-site background rejection capabilities without the complexity of segmentation or complicated PSD algorithms. - The physically-segmented p-type germanium detector technology has proven to be a useful and practical tool in modern nuclear physics. The PSEG technology deserves further development as it has the potential for use in a variety of applications.
Date: June 2009
Creator: Hossbach, Todd W.
Partner: UNT Libraries Government Documents Department

Monte Carlo Simulation for the Majorana Neutrinoless Double-betaDecay Experiment

Description: The Majorana experiment is a proposed HPGe detector array that will primarily search for neutrinoless double-beta decay and dark matter. It will rely on pulse-shape discrimination and crystal segmentation to suppress backgrounds following careful materials selection. A critical aspect of the design phase of Majorana is a reliable simulation of the detector response, pulse formation, and its radioactive backgrounds. We are developing an adaptable and complete simulation based on GEANT 4 to address these requirements and the requirements of a modern, large collaboration experiment. The salient aspects of the simulation are presented. The Majorana experiment is presented in a parallel poster by Kareem Kazkaz.
Date: January 28, 2005
Creator: Henning, Reyco & Collaboration, Majorana
Partner: UNT Libraries Government Documents Department

Half-Life for Double Beta-Decay

Description: Fireman(1) has reported the results of a rather difficult beta-particle coincidence counting experiment in which the decay of Sn{sup 124} by the simultaneous emission of two negative beta-particles, with a half-life between 0.4 x 10{sup 16} years and 0.9 x 10{sup 16} years, seems to have been observed. This note reports the results obtained from a different and somewhat simpler method of looking for the phenomenon of simultaneous emission of two beta-particles. These results are negative so far and show that this process is considerably less probable in the case chosen by us than in that reported by Fireman. The method consists of looking in uranium samples for 90-year Pu{sup 238} which would come from U{sup 238} by the double beta-particle mechanism since Np{sup 238} is heavier than U{sup 238}, which in turn is substantially heavier than Pu{sup 238}, in the isobaric triplet {sub 92}U{sup 238}-{sub 93}Np{sup 238}-{sub 94}Pu{sup 238}. This chemical method of investigation is particularly applicable to this isobaric triplet because there appears to be no other mechanisms to account for the Pu{sup 238} should it be found. The energetics of the situation are summarized in the following diagram, where the disintegration energies are derived from sources which may be traced through a recent compilation.
Date: October 21, 1949
Creator: Levine, C.A.; Ghiorso, A. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Hadronic B decays at BaBar and Belle

Description: The authors review recent results of the BABAR and Belle Collaborations on the {alpha} and {gamma} angles of the unitarity triangle, on the B {yields} K{pi}{pi} Dalitz-plot analyses, and on the searches for baryonic B decays and for B {yields} D{bar D} decays.
Date: August 11, 2008
Creator: Lombardo, Vincenzo & /Milan U. /INFN, Milan
Partner: UNT Libraries Government Documents Department

Measurment of B Decays to phi K gamma

Description: The authors search for the decays B{sup -} {yields} {phi}K{sup -}{gamma} and {bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma} in a data sample of 228 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector. They measure the branching fraction {Beta}(B{sup -} {yields} {phi}K{sup -}{gamma}) = (3.5 {+-} 0.6 {+-} 0.4) x 10{sup -6} and set an upper limit {Beta}({bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma}) < 2.7 x 10{sup -6} at the 90% confidence level. They also measure the direct CP asymmetry in B{sup -} {yields} {phi}K{sup -}{gamma}, {Alpha}{sub CP} = (-26 {+-} 14 {+-} 5)%. The uncertainties are statistical and systematic, respectively.
Date: November 28, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Prospects for CUORE and Latest Results from CUORICINO

Description: CUORE (Cryogenic Underground Observatory for Rare Events) is a proposed next generation experiment designed to search for the neutrinoless DBD of {sup 130}Te using a bolometric technique. The present status of the CUORE is presented along with the latest results from its operating prototype, CUORICINO.
Date: January 5, 2006
Creator: Norman, E B
Partner: UNT Libraries Government Documents Department