Double Decay Research Articles

SEESAW AT LHC THROUGH LEFT–RIGHT SYMMETRY

I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of left–right symmetric theories, which led originally to neutrino mass and the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. Moreover, LHC can measure the masses of the right-handed neutrinos and the right-handed leptonic mixing matrix, which could in turn be used to predict the rates for neutrinoless double decay and lepton flavor violating violating processes. The LR scale at the LHC energies offers great hope of observing these low energy processes in the present and upcoming experiments.

Different sound decay patterns and energy feedback in coupled volumes

Different non-exponential decays such as the concave and the convex double sloped decays in the coupled rooms provide distinct sound qualities. These are commonly considered to occur in the less reverberant sub-room and the more reverberant sub-room, respectively. However, numerical simulations and experiments in this paper show that the demarcation line is not located along the physical boundaries (e.g., the partition and the coupling aperture), but in the more reverberant sub-room. The sound field with the concave double sloped decay penetrates into the auxiliary sub-room to an extent which is influenced by the difference between the two natural reverberations of the sub-rooms. Furthermore the sound energy flows in different regions are investigated, demonstrating how energy feedback leads to the concave double sloped decay.

Determination of the local site occupancy of Eu 3+ ions in ZnAl 2O 4 nanocrystalline powders

Once lanthanides-doped ZnAl 2O 4 have attracted attention for highly efficient phosphors and due to the complexity of this system, this work is focused in the understanding of the local site occupancy of the doped ions in the spinel structure by using Eu 3+ as a spectroscopic probe. Europium(III)-doped ZnAl 2O 4 nanocrystalline powder samples were prepared by the Pechini method. Different heat treatment temperatures and doping levels were investigated. No impurities of residual Eu 2O 3 were observed for the samples with Eu 3+ doping levels up to 10 at.%, indicating that the doping ions are diluted into the host. The luminescence spectroscopy from the Eu 3+ ions revealed the Eu 3+ ions might occupy at least two non-centro-symmetric sites and that the occupation ratio might be dependent on the heat treatment or doping level. It is observed that one site is related to a high covalent environment while at the other the ionic character prevails. This behavior is in agreement with the luminescence lifetime results. The decay curves were fitted according to double first-order decay model and it was confirmed the covalence difference between the two sites and also the population variation with the doping level. There are strong evidences that the europium ions substitute for the aluminum ones in the normal spinel structure. It cannot be disregarded that the dopant ions may be present on the surface of the particles.

Förster-like nonexponential energy transfer kinetics in doped nanoparticles

Computer simulation of the static donor–acceptor energy transfer in samples containing impurity-doped nanoparticles of identical size and in a bulk crystal was performed, compared, and analyzed. A new double nonexponential decay law for nanoparticles was found and explained by two stages of quenching – that of bulk donors and donors on the surface.

Pionic contribution to neutrinoless double beta decay

It is well known that neutrinoless double decay is going to play a crucial role in settling the neutrino properties, which cannot be extracted from the neutrino oscillation data. It is, in particular, expected to settle the absolute scale of neutrino mass and determine whether the neutrinos are Majorana particles, i.e. they coincide with their own antiparticles. In order to extract the average neutrino mass from the data one must be able to estimate the contribution all possible high mass intermediate particles. The latter, which occur in practically all extensions of the standard model, can, in principle, be differentiated from the usual mass term, if data from various targets are available. One, however, must first be able reliably calculate the corresponding nuclear matrix elements. Such calculations are extremely difficult since the effective transition operators are very short ranged. For such operators processes like pionic contributions, which are usually negligible, turn out to be dominant. We study such an effect in a non relativistic quark model for the pion and the nucleon.

Thermodynamics of the Maxwell-Gauss-Bonnet anti-de Sitter black hole with higher derivative gauge corrections

The local and global thermal phase structure for asymptotically anti-de Sitter black holes charged under an abelian gauge group, with both Gauss-Bonnet and quartic field strength corrections, is mapped out for all parameter space. We work in the grand canonical ensemble where the external electric potential is held fixed. The analysis is performed in an arbitrary number of dimensions, for all three possible horizon topologies — spherical, flat or hyperbolic. For spherical horizons, new metastable configurations are exhibited both for the pure Gauss-Bonnet theory as well as the pure higher derivative gauge theory and combinations thereof. In the pure Gauss-Bonnet theory with negative coefficient and five or more spatial dimensions, two locally thermally stable black hole solutions are found for a given temperature. Either one or both of them may be thermally favored over the anti-de Sitter vacuum — corresponding to a single or a double decay channel for the metastable black hole. Similar metastable configurations are uncovered for the theory with pure quartic field strength corrections, as well combinations of the two types of corrections, in three or more spatial dimensions. Finally, a secondary Hawking-Page transition between the smaller thermally favored black hole and thermal anti-de Sitter space is observed when both corrections are turned on and their couplings are both positive.

Plutonium recycling in hydride fueled PWR cores

The classic approach to the recycling of Pu in PWR is to use mixed U-oxide Pu-oxide (MOX) fuel. The mono-recycling of plutonium in PWR transmutes less than 30% of the loaded plutonium, providing only a limited reduction in the long-term radiotoxicity and in the inventory of TRU to be stored in the repository. The primary objective of this study is to assess the feasibility of plutonium recycling in PWR in the form of plutonium hydride, PuH 2, mixed with uranium and zirconium hydride, ZrH 1.6, referred to as PUZH, that is loaded uniformly in each fuel rod. The assessment is performed by comparing the performance of the PUZH fueled core to that of the MOX fueled core. Performance characteristics examined are transmutation effectiveness, proliferation resistance of the discharged fuel and fuel cycle economics. The PUZH loaded core is found superior to the MOX fueled core in terms of the transmutation effectiveness and proliferation resistance. For the reference cycle duration and reference fuel rod diameter and pitch, the percentage of the plutonium loaded that is transmuted in one recycle is 53% for PUZH versus 29% for MOX fuel. That is, the net amount of plutonium transmuted in the first recycle is 55% higher in cores using PUZH than in cores using MOX fuel. Relative to the discharged MOX, the discharged PUZH fuel has smaller fissile plutonium fraction – 45% versus 60%, 15% smaller minor actinides (MA) inventory and more than double spontaneous fission neutron source intensity and decay heat per gram of discharged TRU. Relative to the MOX fuel assembly, the radioactivity of the PUZH fuel assembly is 26% smaller and the decay heat and the neutron yield are only 3% larger. The net effect is that the handling of the discharged PUZH fuel assembly will be comparable in difficulty to that of the discharged MOX assembly while the proliferation resistance of the TRU of the discharged PUZH fuel is enhanced.

Bs1(5830)andBs2*(5840)

In this paper we investigate the strong decays of the two newly observed bottom-strange mesons ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$ in the framework of the quark pair creation model. The two-body strong decay widths of ${B}_{s1}(5830{)}^{0}\ensuremath{\rightarrow}{B}^{*+}{K}^{\ensuremath{-}}$ and ${B}_{s2}^{*}(5840{)}^{0}\ensuremath{\rightarrow}{B}^{+}{K}^{\ensuremath{-}}$, ${B}^{*+}{K}^{\ensuremath{-}}$ are calculated by considering ${B}_{s1}(5830)$ to be a mixture between $|^{1}P_{1}⟩$ and $|^{3}P_{1}⟩$ states, and ${B}_{s2}^{*}(5840)$ to be a $|^{3}P_{2}⟩$ state. The double pion decay of ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$ is supposed to occur via the intermediate state $\ensuremath{\sigma}$ and ${f}_{0}(980)$. Although the double pion decay widths of ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$ are smaller than the two-body strong decay widths of ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$, one suggests future experiments to search the double pion decays of ${B}_{s1}(5830)$ and ${B}_{s2}^{*}(5840)$ due to their sizable decay widths.

Thirteen findings in ten minutes.

Nine architecture students in an architectural acoustics course studied the influence of design on the acoustic response of spaces. Thirteen of their projects will be presented, rapidly, with time to delve into some of them more deeply in response to questions from attendees. Areas of focus include: room shaping and balcony composition; ceiling and canopy height; canopy design; perception and preference of double sloped decays; side wall angle and orientation; room length; very tall ceilings; room width; side wall diffusion; mapping background noise levels; and frequency content of noise.

An analytic expression for the double quantum 1H nuclear magnetic resonance build-up and decay from a Gaussian polymer chain with dynamics governed by a single relaxation time

An analytic result for the double quantum (1)H nuclear magnetic resonance build-up and decay is presented for a polymer chain with Gaussian statistics. The analytic expression is obtained for the particular case of bond vector dynamics governed by a single relaxation time. The result is used to check the accuracy of the commonly used second moment approximation applied to the same problem. This approximation is shown to differ significantly from our exact result over the entire range of relaxation times, set by the relevant interaction constant. We show that this measurement technique is peculiarly sensitive to slow dynamics, and that these slow motions reveal themselves in an experimental time window t that is, curiously, much smaller than the timescale tau of the dynamics being probed. We found t approximately tau(1/3), which enables a wide range of bond vector dynamics to be measured.

Excitation of low‐frequency modes of solid cylinders by evanescent and ordinary propagating waves.

When using sound to detect objects buried beneath the seafloor, often the acoustic source has a large horizontal stand‐off distance. In such situations there is evidence that the incident acoustic wave in sand can have a significant evanescent component. In prior work, organ‐pipe modes of water‐filled shells were excited in a laboratory simulation, the most significant result being the “double spatial decay rate” effect [Marston et al., J. Acoust. Soc. Am. 122, 3034 (2007)]. To further understand the coupling by evanescent waves into low‐frequency modes of cylinders, backscattering by small solid aluminum cylinders was studied with ordinary‐wave illumination. Free‐field experiments identified resonances worthy of investigation in an evanescent wave experiment. Several of the features identified have been reproduced in FEM‐COMSOL calculations by Williams of APL‐UW. For both ordinary and evanescent waves, strong modes were often excited when the cylinder was highly tilted. A further understanding of the modal features was gained by evaluating the temporal variance of the response. Furthermore, the aluminum cylinders also showed an enhanced spatial decay rate when compared to that of the evanescent soundfield. [Work supported by ONR.]

Cross sections ofe+e−→γVVande+e−→γγV

Cross sections of the e{sup +}e{sup -} annihilate into one photon and two vector mesons, such as J/{psi}{rho}, J/{psi}{phi}, and {rho}{phi} at the center of mass energy {radical}(s)=10.58 GeV are calculated. These shed light on the measurement of the e{sup +}e{sup -} annihilation cross section via radiative return in B factories. At another center of mass energy {radical}(s)=3.097 GeV, namely, the J/{psi} resonance peak, the cross sections for the processes e{sup +}e{sup -}{yields}{gamma}VV and e{sup +}e{sup -}{yields}{gamma}{gamma}V (with V being {rho}, {omega}, or {phi}) are calculated with similar methods. These calculations give an estimation of the background levels in the study of radiative or double radiative decays of J/{psi}.

Determination of the Parity of the Neutral Pion via Its Four-Electron Decay

We present a new determination of the parity of the neutral pion via the double Dalitz decay pi0-->e+e-e+e-. Our sample, which consists of 30,511 candidate decays, was collected from KL-->pi0pi0pi0 decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative pi0 parity and place a limit on scalar contributions to the pi0-->e+e-e+e- decay amplitude of less than 3.3% assuming CPT conservation. The pi0gamma*gamma* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be B(pi0-->e+e-e+e-)=(3.26+/-0.18)x10(-5).

Measurement of correlatedbb¯production inpp¯collisions ats=1960 GeV

We present a measurement of the correlated bb¯ production cross section. The data used in this analysis were taken with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider, and correspond to an integrated luminosity of 742 pb−1. We utilize muon pairs with invariant mass 5≤mμμ≤80 GeV/c2 produced by bb¯ double semileptonic decays. For muons with pT≥3 GeV/c and |η|≤0.7, that are produced by b and b¯ quarks with pT≥2 GeV/c and |y|≤1.3, we measure σb→μ,b¯→μ=1549±133 pb. We compare this result with theoretical predictions and previous measurements. We also report the measurement of σc→μ,c¯→μ, a by-product of the study of the background to bb¯ production.19 MoreReceived 9 October 2007DOI:https://doi.org/10.1103/PhysRevD.77.072004©2008 American Physical Society

Final-state radiation and the possibility to test a pion-photon interaction model near the two-pion threshold

Final-state radiation in the process e + e − → π+π− is considered for the cuts used in the analysis of KLOE data at large angles. By means of the Monte Carlo event generator FEVA, effects of nonpointlike behavior of pions are estimated in the framework of resonance perturbation theory. An additional complication related to the ϕ-meson intermediate state is taken into account and the corresponding contributions (the direct decay ϕ → π+π−γ and the double resonance decay ϕ → ρ±π∓ → π+π−γ) are added to FEVA. A method is proposed to test effects of nonpointlike behavior of pions in a model-independent way.

Measurement ofηmeson decays into lepton-antilepton pairs

A search for rare lepton decays of the eta meson was performed using the WASA detector at CELSIUS. Two candidates for double Dalitz decay eta->e+e-e+e- events are reported with a background of 1.3+/-0.2 events. This allows to set an upper limit to the branching ratio of 9.7E-5 (90% CL). The branching ratio for the decay eta->e+e-gamma is determined to (7.8+/-0.5 stat+/-0.8 syst)E-3. An upper limit (90% CL) for the branching ratio for the eta->e+e- decay is 2.7E-5 and a limit for the sum of the eta->mu+mu-mu+mu- and eta->pi+pi-mu+mu- decays is 3.6E-4.

Wet Deposition of Nitrogenous Pollutants and the Effect of Storm Duration and Wind Direction: A Case Study from Inland Southern California

Meteorological factors affecting concentration of dissolved inorganic nitrogen in rain were examined. Rain samples were collected on an event basis from a location 100 km east of the Los Angeles Basin. Analysis of the data demonstrated a double decay function where small increases in rain volume resulted in large decreases in nitrogen concentration. In separate time series collections of individual storms, storm wind direction also influenced nitrogen concentrations

Structure of earthquake occurrence in space, time and magnitude

AbstractDistributions of time between consecutive earthquakes verify an approximately universal scaling law for stationary seismicity. The shape of these distributions is shown to arise as a mixture of one distribution for short‐distance events and an exponential distribution for far‐off events, the distinction from short and long distances being relative to the size of the region studied. The distributions of consecutive distances show a double power law decay and verify an approximate scaling law which guarantees the simultaneous fulfillment of the scaling laws for time. The interplay between space and time can be seen as well by looking at the distribution of distances for a fixed time separation. These results suggest that seismicity can be understood as a series of intertwined independent continuous‐time random walks, with power law‐distributed waiting times and Lévy‐flight jumps. However, a simple model based on these ideas does not capture the invariance of seismicity under renormalization.

Zmiany struktury chemicznej estrow metylowych kwasow tłuszczowych oleju rzepakowego podczas katalitycznego utleniania w temperaturze 200°C

Rapeseed oil methyl ester (Table 1) was oxidized at temp. 200 °C in the presence of cobalt catalyst. Two competitive reactions are going during this process: formation and degradation of peroxides and hydroperoxides being intermediate products (Scheme A). After depletion of the most reactive structures with three or two unsaturated bonds in the material, the reaction of peroxides' decomposition becomes dominant so their concentration in the product decreases. The substrate and product examinations by FT-IR (Fig. 2) and 1 H NMR (Table 2) as well as lowering of iodine value (Fig. la), confirm the double bonds decay. The content of structures with three, two or one unsaturated bond after 25-hour oxidation decreased about 98, 86 and 25 % respectively (Table 3). Composition of volatile products of oxidation (Table 4) (aldehydes, ketones, acids, alkanes and alkenes, lactones and alkylfuranes) confirms the oxidative decomposition of unsaturated fatty acids chains. An increase in molecular weight of about 50 % proves the partial oligomerization of substrate molecules (Fig. 1c).

Ionization in symmetric and nearly symmetric low energy ion–surface collisions

Multiply charged ions are emitted following bombardment of Al(100) and Si(111) by low energy Si+ and P+ ions. The ion formation is attributed to inner-shell electron promotion during a hard collision between symmetric or nearly symmetric atomic species, followed by Auger decay outside the surface. The relative yield of triply charged Si ions for Si+→Si(111) is much smaller than that of triply charged Al ions in direct recoil Si+→Al(100) experiments. This difference can be explained by assuming that only one 2p hole is produced in a Si atom during the symmetric collision, whereas a double 2p hole is also produced in the Al atom following the nearly symmetric Si–Al collision. Further evidence is provided by the complimentary experiment P+→Si(111), where Si3+ regains its intensity and Si4+ emerges as a result of a double 2p hole decay with shake-off.