Double beta decay experiments

The present status of double beta decay experiments are reviewed. The results of the most sensitive experiments, NEMO-3 and CUORICINO, are discussed. Proposals for future double beta decay experiments are considered. In these experiments sensitivity for the effective neutrino mass will be on the level of (0.1-0.01) eV.Comment: 20 pages, 7 fugures; talk at 12-th Lomonosov Conference on Elementary Particle Physics (Moscow, August 25-31, 2005

Search for β+\beta^+EC and ECEC processes in 112^{112}Sn and β−β−\beta^-\beta^- decay of 124^{124}Sn to the excited states of 124^{124}Te

Limits on $\beta^+$EC and ECEC processes in $^{112}$Sn and on $\beta^-\beta^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te have been obtained using a 380 cm$^3$ HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the $^{112}$Sn half-life of $0.92\times 10^{20}$ y for the ECEC(0$\nu$) transition to the $0^+_3$ excited state in $^{112}$Cd (1871.0 keV) has been established. This transition is discussed in the context of a possible enhancement of the decay rate by several orders of magnitude given that the ECEC$(0\nu)$ process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such a process in future experiments are discussed. The $\beta^-\beta^-$ decay limits for $^{124}$Sn to the excited states of $^{124}$Te were obtained on the level of $(0.8-1.2)\times 10^{21}$ y at the 90% C.L.Comment: 17 pages, 5 figure

Search for β+\beta^+EC and ECEC processes in 74^{74}Se

For the first time, limits on double-beta processes in $^{74}$Se have been obtained using a 400 cm$^3$ HPGe detector and an external source consisting of natural selenium powder. At a confidence level of 90%, they are $1.9\times 10^{18}$ y for the $\beta^+$EC$(0\nu + 2\nu)$ transition to the ground state, $7.7\times 10^{18}$ y for the ECEC($2\nu$) transition to the $2^+_1$ excited state in $^{74}$Ge (595.8 keV), $1.1\times 10^{19}$ y for the ECEC($0\nu$) transition to the $2^+_1$ excited state in $^{74}$Ge (595.8 keV) and $5.5\times 10^{18}$ y for the ECEC($2\nu$) and ECEC($0\nu$) transitions to the $2^+_2$ excited state in $^{74}$Ge (1204.2 keV). The last transition is discussed in association with a possible enhancement of the decay rate, in this case by several orders of magnitude, because the ECEC$(0\nu)$ process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such processes in future experiments are discussed.Comment: 13 pages, 2 figures; presented at the 2-nd Symposium on "Neutrino and Dark Matter in Nuclear Physics" (Paris, September 3-9, 2006); v3: minor change

New Results for Double-Beta Decay of Mo-100 to Excited Final States of Ru-100 Using the TUNL-ITEP Apparatus

The coincidence detection efficiency of the TUNL--ITEP apparatus designed for measuring half-life times of two-neutrino double-beta decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the Mo-100 two-neutrino double-beta decay to the first excited 0+ state in Ru-100 has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T_(1/2) = [5.5 (+1.2/-0.8) (stat) +/- 0.3 (syst)] x 10^20 y. Measured two-neutrino double-beta decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in Ru-100 which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics

Жанр как семиотическая структура: на материале русской казахстанской повести

The purpose of this article is to identify and describe the two main genre varieties of the modern Russian Kazakh story. In the course of the study, the following methods were used: theoretical, historical-literary, system-typological approach, poetic-structural analysis of the work. In Russian Kazakh literature, realism and postmodernism are developing in parallel. The story of Nikolai Verevochkin “Singing in the transitions” is a realistic work. Its artistic world contains an image of a system of literary heroes based on determinism, the conditionality of the formation and development of a person’s character by various factors. Determinism contains the strong connection of the structural elements of the story. Verevochkin gradually reveals the characters of the heroes in various situations. The problematics of the story also has a traditional character for the literature of realism. The author demonstrates commitment to humanism, which is the ideological basis of realism. The article also analyzes the work of postmodernism — the story of Asel Omar “Alphabet”. The definition of “story-lexicon”, introduced by the author of the article, reflects the genre and generic features of this work. The story-lexicon Asel Omar consists of micro-novellas, which at the same time are dictionary entries. The peculiarity of these articles is that they are based on a certain storyline. The micronovelas are arranged in alphabetical order, which gave the author of this article reason to call them dictionary entries. Asel Omar’s lexicon story, in contrast to Nikolai Verevochkin’s story, is written in a freer plot form. The application of the essay principle allowed the author to create a reasoning story. The main thing for Assel Omar is to express her thoughts on various topics. The work of Nikolai Verevochkin is a narrative story. Thus, in modern Russian Kazakh prose, two main types of story are presented — realistic and postmodern story. Due to historical and cultural reasons, the realistic story prevails. The work of Asel Omar “Alphabet” is a unique example of a postmodern story-lexicon in modern Kazakh literature.Лингвистический анализ художественного текста на материале произведений русской казахстанской литературы остается актуальной проблемой современного языкознания, поскольку в ней параллельно развиваются реализм и постмодернизм. Цель исследования заключается в выявлении и описании двух основных жанровых разновидностей современной русской казахстанской повести. В ходе проведенного исследования были использованы следующие методы: теоретический, историко-литературный, системно-типологический подход, поэтико-структурный анализ произведения. Повесть Николая Веревочкина «Поющие в переходах» - реалистическое произведение. В ее художественном мире содержится изображение системы литературных героев на основе детерминизма, обусловленности формирования и развития характера человека различными факторами. Детерминизм определяет прочную связь структурных элементов повести. Веревочкин постепенно раскрывает характеры основных героев в различных ситуациях. Проблематика повести также носит традиционный для литературы реализма характер. Автор демонстрирует приверженность гуманизму, который является мировоззренческой основой реализма. Также дан анализ произведения постмодернизма - повести Асель Омар «Алфавит». Определение «повесть-лексикон», введенное автором, отражает жанрово-родовые особенности этого произведения. Повесть-лексикон Асель Омар состоит из микроновелл, которые одновременно являются словарными статьями. Особенность этих статей состоит в том, что они основаны на определенной сюжетной линии. Микроновеллы расположены в алфавитном порядке, что дало основание автору настоящей статьи назвать их словарными статьями. Повесть-лексикон Асель Омар, в отличие от повести Николая Веревочкина, написана в более свободной сюжетной форме. Применение принципа эссе позволило автору создать повесть-рассуждение. Главное для Асель Омар - выразить мысли по различным темам. Произведение Николая Веревочкина является повестью-историей. Таким образом, в современной русской казахстанской прозе представлены два основных типа повести - реалистическая и повесть постмодернизма. В силу исторических и культурных причин преобладает реалистическая повесть. Произведение Асель Омар «Алфавит» является уникальным примером постмодернистской повести-лексикона в современной казахстанской литературе

Pulse Shape Analysis and Identification of Multipoint Events in a Large-Volume Proportional Counter in an Experimental Search for 2K Capture Kr-78

A pulse shape analysis algorithm and a method for suppressing the noise component of signals from a large copper proportional counter in the experiment aimed at searching for 2K capture of Kr-78 are described. These signals correspond to a compound event with different numbers of charge clusters due to from primary ionization is formed by these signals. A technique for separating single- and multipoint events and determining the charge in individual clusters is presented. Using the Daubechies wavelets in multiresolutional signal analysis, it is possible to increase the sensitivity and the resolution in extraction of multipoint events in the detector by a factor of 3-4.Comment: 10 pages, 8 figures. submitted to Instruments and Experimental Techniques; ISSN 0020/441

Nuclear emulsion with molybdenum filling for observation of ββ\beta\beta decay

The usage of nuclear emulsion with molybdenum filling for observation of $\beta\beta$ decay are shown to be possible. Estimates for 1 kg of $^{100}$Mo with zero background give the sensitivity for the $0\nu\beta\beta$ decay of $^{100}$Mo at the level of $\sim 1.5\cdot 10^{24}$ y for 1 year of measurement.Comment: 7 pages, 3 figure

Measurement of double beta decay of 100Mo to excited states in the NEMO 3 experiment

The double beta decay of 100Mo to the 0^+_1 and 2^+_1 excited states of 100Ru is studied using the NEMO 3 data. After the analysis of 8024 h of data the half-life for the two-neutrino double beta decay of 100Mo to the excited 0^+_1 state is measured to be T^(2nu)_1/2 = [5.7^{+1.3}_{-0.9}(stat)+/-0.8(syst)]x 10^20 y. The signal-to-background ratio is equal to 3. Information about energy and angular distributions of emitted electrons is also obtained. No evidence for neutrinoless double beta decay to the excited 0^+_1 state has been found. The corresponding half-life limit is T^(0nu)_1/2(0^+ --> 0^+_1) > 8.9 x 10^22 y (at 90% C.L.). The search for the double beta decay to the 2^+_1 excited state has allowed the determination of limits on the half-life for the two neutrino mode T^(2nu)_1/2(0^+ --> 2^+_1) > 1.1 x 10^21 y (at 90% C.L.) and for the neutrinoless mode T^(0nu)_1/2(0^+ --> 2^+_1) > 1.6 x 10^23 y (at 90% C.L.).Comment: 23 pages, 7 figures, 4 tables, submitted to Nucl. Phy

On the low-temperature performances of THGEM and THGEM/G-APD multipliers in gaseous and two-phase Xe

The performances of THGEM multipliers in two-phase Xe avalanche mode are presented for the first time. Additional results on THGEM operation in gaseous Xe at cryogenic temperatures are provided. Stable operation of a double-THGEM multiplier was demonstrated in two-phase Xe with gains reaching 600. These are compared to existing data, summarized here for two-phase Ar, Kr and Xe avalanche detectors incorporating GEM and THGEM multipliers. The optical readout of THGEMs with Geiger-mode Avalanche Photodiodes (G-APDs) has been investigated in gaseous Xe at cryogenic temperature; avalanche scintillations were recorded in the Near Infrared (NIR) at wavelengths of up to 950 nm. At avalanche charge gain of 350, the double-THGEM/G-APD multiplier yielded 0.07 photoelectrons per initial ionization electron, corresponding to an avalanche scintillation yield of 0.7 NIR photons per avalanche electron over 4pi. The results are compared with those of two-phase Ar avalanche detectors. The advantages, limitations and possible applications are discussed.Comment: 22 pages, 14 figures. Revised Figs. 10,11 and Table 1. To be published in JINS

Causality and statistics on the Groenewold-Moyal plane

Quantum theories constructed on the noncommutative spacetime called the Groenewold-Moyal plane exhibit many interesting properties such as Lorentz and CPT noninvariance, causality violation and twisted statistics. We show that such violations lead to many striking features that may be tested experimentally. These theories predict Pauli forbidden transitions due to twisted statistics, anisotropies in the cosmic microwave background radiation due to correlations of observables in spacelike regions and Lorentz and CPT violations in scattering amplitudes.Comment: 12 pages, 1 figure. Based on the talk given by APB at the Workshop "Theoretical and Experimental Aspects of the Spin Statisics Connection and Related Symmetries", Stazione Marittima Conference Center, Trieste, Italy from the 21st to the 25th of October 200