Double Decay Research Articles

A qualitative criterion for the reverberant fields for organ music and a means of obtaining it

Organists and organ builders desire long reverberation times for their instruments. A simple statement of a time is an inadequate specification for the acoustic response of a venue intended for medium to larger organs. An important added specification requirement is that the reverberation decay curve be steep at first and be much less so later if satisfactory clarity is to be achieved. Data is presented to illustrate and establish this criterion. Research is cited to demonstrate how the double slope reverberation decay can be achieved by the use of coupled spaces adjacent to a main performing room. Data is given to demonstrate how some symphony halls have realized the use of this technique.

Bottom production cross section from double muonic decays of b-flavoured hadrons in 920 GeV proton-nucleus collisions

The bb¯ production cross section in 920 GeV proton-nucleus fixed target collisions is measured by observing double muonic decays of b-flavoured hadrons in the kinematic region −0.3<xF(μ)<0.15. A total number of 83±12bb¯ events is obtained with a likelihood fit of the signal and background simulated events to the data. The resulting cross section is σbb¯=17.5±2.6stat±3.3sys nb/nucleon, or, when combined with a previous HERA-B measurement of similar precision, σbb¯=15.8±1.7stat±1.3sysuncorr±2.0syscorr nb/nucleon, which is consistent with recent NLO calculations.

Review of Low Energy Neutrinos

Some issues regarding low energy neutrinos are reviewed. We focus on three aspects i)We show that by employing very low energy (a few keV) electron neutrinos, neutrino disappearance oscillations can be investigated by detecting recoiling electrons with low threshold spherical gaseous TPC's. In such an experiment, which is sensitive to the small mixing angle θ13, the novel feature is that the oscillation length is so small that the full oscillation takes place inside the detector. Thus one can determine accurately all the oscillation parameters and, in particular, measure or set a good limit on θ13. ii) Low threshold gaseous TPC detectors can also be used in detecting nuclear recoils by exploiting the neutral current interaction. Thus these robust and stable detectors can be employed in supernova neutrino detection. iii) The lepton violating neutrinoless double decay is investigated focusing on how the absolute neutrino mass can be extracted from the data.

Nuclear structure and the double beta decay

In the Standard Model, the neutrinoless double beta decay is not allowed but it is allowed in most Grand Unified Theories (GUTs). The neutrino must be a Majorana particle (identical with its antiparticles) and must have a mass to allow the neutrinoless double beta decay. Apart from one claim that the neutrinoless double beta decay in 76Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow us to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUTs and the minimal R-parity violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left–right symmetric GUTs. For that one has to assume that the specific mechanism is the leading one for the neutrinoless double decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present contribution, we discuss the accuracy of the present status of calculating the nuclear matrix elements and the corresponding limits of GUTs and supersymmetric parameters.

A field study of the use of methoprene for West Nile virus mosquito control

The occurrence of vector-borne West Nile virus in Canada has resulted in the use of larvicides for widespread urban mosquito control. To determine the fate of larvicides in storm drainage systems, three catch basins in Toronto, Ontario were treated with methoprene (Altosid) pellets three times over the summer of 2003, at the recommended mosquito control dose of 0.7 g per catch basin. Daily monitoring included: methoprene concentration analysis, precipitation in the area, the presence of mosquito larvae, and the chemical composition of catch basin sumps. A model catch basin in the laboratory was also dosed with methoprene pellets and sampled daily to observe concentration over time under quiescent conditions. It was found that (1) the methoprene concentration at the catch basins fell below the minimum lethal concentration after one or two weeks after treatment; (2) rainfall flushed methoprene from the catch basins to the storm sewer outfall at concentrations lower than the level that may cause ecosystem damage; and (3) the methoprene concentrations in the experiments exhibited a double peak decay pattern. Key words: methoprene, Altosid, West Nile virus, larvicide, catch basin, Toronto.

$D^0 \bar{D}^0$ Quantum Correlations, Mixing, and Strong Phases

Because of the quantum correlation between the pair-produced D0 and [Formula: see text] from the decay of the ψ(3770), the time-integrated single and double tag decay rates depend on charm mixing amplitudes, doubly-Cabibbo-suppressed amplitudes, and the relative strong phase δ between D0 and [Formula: see text] decays to identical final states. Using 281 pb-1 collected with the CLEO-c detector on the ψ(3770) resonance, we measure the absolute branching fractions of D0 decays to hadronic flavored states, CP eigenstates, and semileptonic final states to determine the relative strong phase cos δ and to limit the mixing amplitude y.

Weak radiativeBdecays

We study the (tree-level) weak radiative decays of $B$ mesons. We present a numerical estimate for the inclusive $b\ensuremath{\rightarrow}{X}_{c}\ensuremath{\gamma}(\ensuremath{\gamma})$ modes based on the free-quark decay. We then review what is known for the $B\ensuremath{\rightarrow}{D}^{\ensuremath{\star}}\ensuremath{\gamma}$ modes in the framework of heavy quark effective theory and chiral perturbation theory. Finally, we extend these ideas to the double radiative decay modes $B\ensuremath{\rightarrow}D\ensuremath{\gamma}\ensuremath{\gamma}$. We find that the $b\ensuremath{\rightarrow}{X}_{c}\ensuremath{\gamma}\ensuremath{\gamma}$ rate is about an order of magnitude larger than the corresponding $b\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}\ensuremath{\gamma}$ rate. We also find the branching ratio for the $B\ensuremath{\rightarrow}D\ensuremath{\gamma}\ensuremath{\gamma}$ mode with most favorable CKM angles at the $\mathrm{\text{few}}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ level, comparable to predictions for $B\ensuremath{\rightarrow}K\ensuremath{\gamma}\ensuremath{\gamma}$.

Low-level techniques applied in BOREXINO and GERDA

BOREXINO and GERDA are experiments which require an ultra-low background. The first one is a large scale, real-time liquid scintillation detector for low energy solar neutrinos, where only a few tens of events per day are expected. GERDA will look for the neutrinoless double decay of 76Ge. To minimize the background bare germanium crystals (enriched up to 86% in 76Ge) will be operated in ultra-pure liquid nitrogen or liquid argon.

Formula omitted] decay in the model with one universal extra dimension

We estimate the beyond the Standard Model (SM) contribution to the Bs,d→γγ double radiative decay in the framework of the model with one universal extra dimension. This contribution gives a ∼3(6)% enhancement of the branching ratio calculated in the SM for Bs(d)→γγ (without QCD corrections).

Coupled Volumes: Secondary Room Reverberance and the Double-Sloped Decay of Concert Halls

The coupled volume concert hall and its signature double sloped sound decay aim to partially reconcile the often-competing qualities of clarity and reverberance. A concert hall is conceived with a fixed geometric volume, form, and aperture size. A coupled volume is attached and its materiality is established as variable. Both statistical and geometric relative analyses suggest a highly sensitive relationship between the coupled volume reverberation time and the double-sloped condition.

Television families: Is something wrong in suburbia?

Television Families: Is Something Wrong in Suburbia? William Douglas. Mahwah, NJ: Lawrence Erlbaum Associates. 2003. 197 pp. ISBN 0-8058-4013-3. $22.50 (paper). In his book, William Douglas provides a thorough analysis of the portrayal of families in entertainment media. While most of the focus is on the television family, Douglas discusses the family as seen in important predecessors: vaudeville, radio, and comic strips. He sets his analysis of the family in popular culture (e.g., the relationship between Blondie and Dagwood) against the prevailing socioeconomic conditions of families (e.g., the Lynd's study of Middletown), providing a context with which to understand the relationship between media and society. He centers on the suburban family, both because suburbia became the desired living location during the advent of television and also because most television families lived there as well. The book is organized first chronologically and then thematically in chapters that cover spousal relationships, parent-child and sibling relationships, African American families, elderly family members, and the divergence between middle-class and working families. Douglas focuses on family structure, the nature of family roles, and the more personal and relational aspects of television families. The impact of gender, class, and age in both real and media families is given much attention. Most notably, Douglas focuses on the changing roles for women that strongly influenced the structure of family life over the course of the 20th century. He demonstrates how Tarzan and Jane principles were widespread throughout middle-class, young, White families on television but notes how such principles did not apply to working-class families or ethnic and racial minorities who were rarely portrayed on television at all. The elderly have also been underrepresented throughout television's history, and more recently, children have become less visible as well. Is something wrong in suburbia? According to the author's analysis of the double decay hypothesis, which addresses the deterioration of the family in general and how that is reflected in popular culture, it appears that the answer is yes. Though there are exceptions on television, minority families other than African American families are virtually absent from the screen, and when African American families are portrayed, they are portrayed in more negative ways than White families; while depictions of middle-class, husband-wife roles are more egalitarian on television than in the past, husbands still appear to hold more family power than their wives; working-class families' interactions are marked by hostility and hardship; parents are not sufficiently involved in childrearing; and sibling relationships have become more contentious. …

Poly(epichlorohydrin) modified with 3,4,5‐tris(dodecyloxy)benzoate: The structure and dynamics of the aliphatic side chains in the columnar mesophase

AbstractWe investigated the dynamics and structure of the aliphatic side chains of a randomly grafted copolymer, obtained through the chemical modification of poly(epichlorohydrin) with potassium 3,4,5‐tris(dodecyloxy)benzoate, with solid‐state 13C NMR. Below 283 K, the aliphatic chains partially crystallized in an all‐anti conformation. The calorimetric data were compatible with an orthorhombic packing. Below 323 K, the polymer exhibited a columnar mesophase. Spin–lattice relaxation times were determined in this temperature range and at 333 K, that is, in the isotropic phase. In the liquid‐crystalline state, some carbons exhibited a double decay in the spin–lattice relaxation, and this was attributed to presence of the liquid‐crystalline phase. This hypothesis was supported by a conformational analysis performed by molecular modeling. The activation energies of the relaxation processes in the mesophase were also estimated. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2099–2111, 2005

SDECAY: a Fortran code for the decays of the supersymmetric particles in the MSSM

We present the Fortran code SDECAY, which calculates the decay widths and branching ratios of all the supersymmetric particles in the Minimal Supersymmetric Standard Model, including higher order effects. Besides the usual two-body decays of sfermions and gauginos and the three-body decays of charginos, neutralinos and gluinos, we have also implemented the three-body decays of stops and sbottoms, and even the four-body decays of the stop; the important loop-induced decay modes are also included. The QCD corrections to the two-body decays involving strongly interacting particles and the dominant components of the electroweak corrections to all decay modes are implemented. Program summary Title of program: SDECAY Version 1.1a (March 2005) Catalogue identifier: ADVJ Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADVJ Program obtainable: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: none Computer for which the program is designed: Any with a Fortran77 system Operating systems under which the program has been tested: Linux, Unix Typical running time: A few seconds on modern personal computers and workstations Programming language used: Fortran77 No. of lines in distributed program, including test data, etc.: 59 621 No. of bytes in distributed program, including test data, etc.: 338 478 Distribution format: tar.gz Memory required to execute (with test data): 7.3 MB Distribution format: ASCII Nature of physical problem: Numerical calculation of the decay widths and branching ratios of supersymmetric particles in the Minimal Supersymmetric Standard Model (MSSM). The program calculates two-, three- and four-body decays and loop decays. It includes the SUSY-QCD corrections to two-body decays involving strongly interacting particles. The top-quark decays within the MSSM are evaluated as well. Method of solution: Two-dimensional numerical integration of the analytic formulae for the double differential decay widths of the three-body decays. The other decay widths are calculated analytically. Restrictions on the complexity of the problem: In the higher order decay modes the total decay widths of the virtually exchanged (s)particles are not included in their respective propagators. The higher order decays are calculated when the two-body decays are kinematically closed.

Predictions forB→Kγγ decays

We present a phenomenological study of the rare double radiative decay $B\to K \gamma\gamma$ in the Standard Model (SM) and beyond. Using the operator product expansion (OPE) technique, we estimate the short-distance (SD) contribution to the decay amplitude in a region of the phase space which is around the point where all decay products have energy $\sim m_b/3$ in the rest frame of the $B$-meson. At lowest order in 1/Q, where $Q$ is of order $m_b$, the $B\to K \gamma\gamma$ matrix element is then expressed in terms of the usual $B\to K$ form factors known from semileptonic rare decays. The integrated SD branching ratio in the SM in the OPE region turns out to be $\Delta {\cal{B}}(B \to K \gamma \gamma)_{SM}^{OPE} \simeq 1 \times 10^{-9}$. We work out the di-photon invariant mass distribution with and without the resonant background through $B\to K \{\eta_c,\chi_{c0}\}\to K\gamma \gamma$. In the SM, the resonance contribution is dominant in the region of phase space where the OPE is valid. The present experimental upper limit on $B_s \to \tau^+ \tau^-$ decays, which constrains the scalar/pseudoscalar Four-Fermi operators with $\tau^+ \tau^-$, leaves considerable room for new physics in the one-particle-irreducible contribution to $B\to K \gamma \gamma$ decays. In this case, we find that the SD $B\to K \gamma \gamma$ branching ratio can be enhanced by one order of magnitude with respect to its SM value and the SD contribution can lie outside of the resonance peaks.

Five sensitivities of the coupled volume/double sloped system

Stop chord measurements taken in an existing coupled volume concert hall, established statistically-based formulas, ray-tracing-software simulations, and headphone listening perception/preference studies imply a fickle relationship between the coupled volume concert hall, the double-sloped sound decay, and the listener. The two halls examined in this study suggest five sensitivities of the system: (1) To produce a double sloped sound decay, the coupled volume must be exceedingly more reverberant than the main hall to which it is attached. (2) To produce a double sloped sound decay, the sonic aperture linking the coupled volume to the main hall must be exceedingly small. (3) Maintaining low levels of background noise—always essential when designing spaces for music listening—is especially important if the double sloped impulse response is to be perceived above the noise floor. (4) Listeners who sit near the apertures probably hear something different than those who sit nearer to the center of the hall. (5) It is unclear whether subjects taking a paired comparison test prefer a double sloped auralization to a classic Sabine auralization.

First results on neutrinoless double beta decay of 130Te with the calorimetric CUORICINO experiment

The first results are reported on the limit for neutrinoless double decay of 130Te obtained with the new bolometric experiment CUORICINO. The set-up consists of 44 cubic crystals of natural TeO2, 5 cm on the side and 18 crystals of 3×3×6 cm3. Four of these latter crystals are made with isotopically enriched materials: two in 128Te and two others in 130Te. With a sensitive mass of ∼40 kg, our array is by far the most massive running cryogenic detector to search for rare events. The array is operated at a temperature of ∼10 mK in a dilution refrigerator under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. The counting rate in the region of neutrinoless double beta decay is ∼0.2 counts keV−1kg−1y−1, among the lowest in this type of experiment. No evidence for neutrinoless double beta decay is found with the present statistics obtained in about three months with a live time of 72%. The corresponding lower limit for the lifetime of this process is of 5.5×1023 years at 90% C.L. The corresponding limit for the effective neutrino mass ranges between 0.37 to 1.9 eV depending on the theoretically calculated nuclear matrix elements used. This constraint is the most restrictive one except those obtained with Ge diodes, and is comparable to them.

Measurement of the average time-integrated mixing probability ofb-flavored hadrons produced at the Fermilab Tevatron

We have measured the number of like-sign (LS) and opposite-sign (OS) lepton pairs arising from double semileptonic decays of $b$ and $\bar{b}$-hadrons, pair-produced at the Fermilab Tevatron collider. The data samples were collected with the Collider Detector at Fermilab (CDF) during the 1992-1995 collider run by triggering on the existence of $\mu \mu$ and $e \mu$ candidates in an event. The observed ratio of LS to OS dileptons leads to a measurement of the average time-integrated mixing probability of all produced $b$-flavored hadrons which decay weakly, $\bar{\chi} = 0.152 \pm 0.007$ (stat.) $\pm 0.011$ (syst.), that is significantly larger than the world average $\bar{\chi} = 0.118 \pm 0.005$.

Two-neutrino double beta decay of 76Ge within deformed QRPA

The effect of deformation on the two-neutrino double decay (2 νββ-decay) for ground state transition 76 Ge→ 76 Se is studied in the framework of the deformed QRPA with separable Gamow–Teller residual interaction. We found that when the parent and daughter nuclei have different deformations, the 2 νββ-decay matrix element is suppressed with respect to the case of 2 νββ decay between nuclei having the same deformation, in particular, spherical going to spherical. An advantage of this suppression mechanism in comparison with that associated with ground state correlations is that it allows a simultaneous description of the single β and the 2 νββ-decay. By performing a detail calculation of the 2 νββ-decay of 76Ge, it is found that the states of intermediate nucleus lying in the region of the Gamow–Teller resonance contribute significantly to the matrix element of this process.

Pulse-shape discrimination in the IGEX experiment

The IGEX experiment has been operating enriched germanium detectors in the Canfranc Underground Laboratory (Spain) in a search for the neutrinoless double decay of 76Ge. The implementation of pulse-shape discrimination techniques to reduce the radioactive background is described in detail. This analysis has been applied to a fraction of the IGEX data, leading to a rejection of ∼60% of their background, in the region of interest (from 2 to 2.5MeV), down to ∼0.09c/keVkgyr.

Brownian dynamics simulations of aging colloidal gels

The aging of colloidal gels is investigated using very long duration Brownian dynamics simulations. The Asakura-Oosawa description of the depletion interaction is used to model a simple colloid polymer mixture. Several regimes are identified during gel formation. The intermediate scattering function displays a double decay characteristic of systems where some kinetic processes are frozen. The beta relaxation at short times is explained in terms of the Krall-Weitz model for the decorrelation due to the elastic modes present. The alpha relaxation at long times is well described by a stretched exponential, showing a wide spectrum of relaxation times for which the q dependence is tau(alpha)=q(-2.2), lower than for diffusion. For the shortest waiting times, a combination of two stretched exponentials is used, suggesting a bimodal distribution. The extracted relaxation times vary with waiting time as tau(alpha)=tau(0.66)(w), more slowly than in the simple aging case. The real space displacements are found to be strongly non-Gaussian, correlated in space and time. We were unable to find clear evidence that the gel aging was driven by internal stresses. Rather, we hypothesize that in this case of weakly interacting gels, the aging behavior arises due to the thermal diffusion of strands, constrained by the percolating network, which ruptures discontinuously. Although the mechanisms differ, the similarity of some of the results to aging of glasses is striking.