Search results for "DECAY"
showing 10 items of 2087 documents
A BSM hunting guide after Run I
2017
La tesis doctoral tiene como objetivo explorar algunos de los diversos campos de actividad de la física de partículas tras el descubrimiento del bosón de Higgs en el LHC. Por ello, incluye trabajo tanto en extensiones del Modelo Estándar (SM) como la Supersimetría (SUSY), la formación de la estructura del universo tras el periodo de inflación primigenia y un modelo para neutrinos dextrógiros (RH-neutrino). Todo ello ha sido analizado con un cariz fenomenológico, para que la teoría no se despegue demasiado de los diferentes experimentos que pueden confirmarla o refutarla. En cuanto a SUSY se refiere, se decidió hacer un estudio fenomenológico del sector de Higgs de MSSM (modelo con un número…
Spin-multipole nuclear matrix elements in the pn quasiparticle random-phase approximation: Implications for β and ββ half-lives
2017
Half-lives for 148 potentially measurable 2nd-, 3rd-, 4th-, 5th-, 6th-, and 7th-forbidden unique beta transitions are predicted. To achieve this, the ratio of the nuclear matrix elements (NMEs), calculated by the proton-neutron quasiparticle random-phase approximation (pnQRPA), MpnQRPA, and a two-quasiparticle (two-qp) model, Mqp, is studied and compared with earlier calculations for the allowed Gamow-Teller (GT) 1+ and first-forbidden spin-dipole (SD) 2− transitions. The present calculations are done using realistic single-particle model spaces and G-matrix based microscopic two-body interactions. In terms of the ratio k = MpnQRPA/Mqp the studied decays fall into two groups: for GROUP 1, w…
Observation of the rare B(s)(0) + decay from the combined analysis of CMS and LHCb data.
2015
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported licence.-- et al.
Decay estimates for time-fractional and other non-local in time subdiffusion equations in R^d
2016
We prove optimal estimates for the decay in time of solutions to a rather general class of non-local in time subdiffusion equations in R d . An important special case is the timefractional diffusion equation, which has seen much interest during the last years, mostly due to its applications in the modeling of anomalous diffusion processes. We follow three different approaches and techniques to study this particular case: (A) estimates based on the fundamental solution and Young’s inequality, (B) Fourier multiplier methods, and (C) the energy method. It turns out that the decay behaviour is markedly different from the heat equation case, in particular there occurs a critical dimension phenom…
Towards saturation of the electron-capture delayed fission probability : The new isotopes 240Es and 236Bk
2017
The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n)240Es. Half-lives of 6(2) sand 22+13−6swere obtained for 240Es and 236Bk, respectively. Two groups of αparticles with energies Eα=8.19(3) MeVand 8.09(3) MeVwere unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6)and 0.04(2)were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes. peerReviewed
Quantum-state-selective decay spectroscopy of 213Ra
2017
An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the …
117番元素Ts合成のための48Ca+249Bk融合反応
2019
We have performed an experiment to synthesize the element 117 (Ts) with the $^{48}$Ca+$^{249}$Bk fusion reaction. Four $\alpha$-decay chains attributed to the element 117 were observed. Two of them were long decay chains which can be assigned to the one originating from the $\alpha$ decay of $^{294}$Ts. The other two were short decay chains which are consistent with the one originating from the $\alpha$ decay of $^{293}$Ts. We have compared the present results with the literature data, and found that our present results mostly confirmed the literature data, leading to the firm confirmation of the synthesis of the element 117.
Positron Studies of Subsurface Zone in Titanium Created in Sliding Wear
2014
Positron annihilation studies of the subsurface zone constituted during dry sliding in pure titanium are reported. A new type of defect depth profile in this zone, which is not an exponential decay usually reported for other metals and alloys, is observed. Two layers in the subsurface zone are present in this metal. In the layer adjacent to the worn surface, the characteristic plateau of the mean positron lifetime that extends to a depth of 60–70 μm was observed. Small vacancy clusters and dislocations were recognized in this layer. At deeper zone, the mean positron lifetime decreased exponentially in the manner typical for the other metals. In this zone, vacancy clusters increase in size a…
Temporal loudness weights in background noise: Data and models
2019
Previous studies consistently showed that human listeners primarily consider the beginning of a time-varying sound when judging its overall loudness, and place less weight on subsequent temporal portions. However, all experiments studying this primacy effect in temporal loudness weights presented the target sound in quiet. Here, we compared temporal weights when the target sound was either presented in quiet or in a continuous background noise, and for a variation in the level of the target sound across a range of 60 dB. The target sound was a time-varying narrowband noise, the background noise was a continuous bandpass-filtered noise. In all conditions, we observed the expected primacy eff…
Measurement of the production of high-pT electrons from heavy-flavour hadron decays in Pb–Pb collisions at √sNN = 2.76 TeV
2017
Electrons from heavy-flavour hadron decays (charm and beauty) were measured with the ALICE detector in Pb–Pb collisions at a centre-of-mass of energy √sNN = 2.76 TeV. The transverse momentum (pT) differential production yields at mid-rapidity were used to calculate the nuclear modification factor RAA in the interval 3 < pT < 18 GeV/c. The RAA shows a strong suppression compared to binary scaling of pp collisions at the same energy (up to a factor of 4) in the 10% most central Pb–Pb collisions. There is a centrality trend of suppression, and a weaker suppression (down to a factor of 2) in semi-peripheral (50–80%) collisions is observed. The suppression of electrons in this broad pT interval …