Search results for "DECAY"
showing 10 items of 2087 documents
Analysis of light neutrino exchange and short-range mechanisms in 0νββ decay
2020
Neutrinoless double beta decay (0νββ) is a crucial test for lepton number violation. Observation of this process would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. Focusing on so-called short-range operators of 0νββ and their potential interplay with the standard light Majorana neutrino exchange, we present the first complete calculation of the relevant nuclear matrix elements, performed within the interacting boson model (IBM-2). Furthermore, we calculate the relevant phase space factors using exact Dirac electron wave functions, taking into account the finite nuclear size and screening by the electron cloud. The obtained numerical r…
"Selection efficiency" of "Search for $B^{+}\to K^{+}\nu\bar{\nu}$ decays using an inclusive tagging method at Belle II"
2022
Signal efficiency as a function of the dineutrino invariant mass squared $q^{2}$ for events in the signal region (SR) ($\rm{BDT}_{1} > 0.9$ and $\rm{BDT}_{2} > 0.95$). The error bars indicate the statistical uncertainty.
"Expected and observed limit" of "Search for $B^{+}\to K^{+}\nu\bar{\nu}$ decays using an inclusive tagging method at Belle II"
2022
CL$_{s}$ value as a function of the branching fraction of $B^{+} \rightarrow K^{+} \nu \bar{\nu}$ for expected and observed signal yields and the corresponding upper limits at 90% confidence level (CL). The expected limit is derived for the background-only hypothesis. The observed limit is derived from a simultaneous fit to the on-resonance and off-resonance data, corresponding to an integrated luminosity of 63 fb$^{−1}$ and 9 fb$^{−1}$, respectively.
Structure of superheavy nuclei along decay chains of element 115
2014
[Introduction] A recent high-resolution α , X -ray, and γ -ray coincidence-spectroscopy experiment offered the first glimpse of excitation schemes of isotopes along α -decay chains of Z = 115. To understand these observations and to make predictions about shell structure of superheavy nuclei below 288 115, we employ two complementary mean-field models: the self-consistent Skyrme energy density functional approach and the macroscopic-microscopic Nilsson model. We discuss the spectroscopic information carried by the new data. In particular, candidates for the experimentally observed E 1 transitions in 276 Mt are proposed. We find that the presence and nature of low-energy E 1 transitions in w…
Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at √sNN = 2.76 TeV
2016
The elliptic flow, v2, of muons from heavy-flavour hadron decays at forward rapidity (2.5 < y < 4) is measured in Pb–Pb collisions at √sNN = 2.76 TeV with the ALICE detector at the LHC. The scalar product, two- and four-particle Q cumulants and Lee–Yang zeros methods are used. The dependence of the v2 of muons from heavy-flavour hadron decays on the collision centrality, in the range 0–40%, and on transverse momentum, pT, is studied in the interval 3 < pT < 10 GeV/c. A positive v2 is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10–20% and 20–40% centrality classes) for the pT interval from 3 to about 5 GeV/c with a significance larger than 3σ, ba…
Molecular Approaches Fighting Nonsense
2021
Nonsense mutations are the result of single nucleotide substitutions in the DNA that change a sense codon (coding for an amino acid) to a nonsense or premature termination codon (PTC) within the coding region of the mRNA [...]
Precision mass measurements of 67Fe and 69,70Co: Nuclear structure toward N = 40 and impact on r-process reaction rates
2020
Accurate mass measurements of neutron-rich iron and cobalt isotopes 67Fe and 69,70Co have been realized with the JYFLTRAP double Penning-trap mass spectrometer. With novel ion-manipulation techniques, the masses of the 69,70Co ground states and the 1/2− isomer in 69Co have been extracted for the first time. The measurements remove ambiguities in the previous mass values and yield a smoother trend on the mass surface, extending it beyond N=40. The moderate N=40 subshell gap has been found to weaken below 68Ni, a region known for shape coexistence and increased collectivity. The excitation energy for the 1/2− intruder state in 69Co has been determined for the first time and is compared to lar…
Shape evolution in even-even N≤126, Z≥82 nuclei
2010
The shape evolution in the neutron-de cient lead, polonium and radium nuclei has been investigated via in-beam and delayed y-ray and conversion electron spectroscopy. The lead isotope 180Pb is found to still exhibit prolate excited structure, related to the known intruder structures in the heavier isotopes. The production cross-section of 180Pb was only 10 nb, one of the lowest ever employed in an in-beam experiment. A candidate for an excited prolate band was found in 192Po, making it the rst polonium isotope for which both oblate and prolate rotational bands have been established. Contrary to the previous results, the current experiments indicate that the onset of deformation in the radiu…
K-kertaisesti kiellettyjen uniikkien β-siirtymien faasiavaruusintegraalit
2018
Tässä tutkimuksessa perehdytään K-kertaisesti kiellettyjen uniikkien beetasiirtymien faasiavaruusintegraaleihin. K-kertaisesti kielletyt uniikit beetasiirtymät ovat beetahajoamisten alaryhmä, ja faasiavaruusintegraalit kuvaavat hajoamisreaktion jälkeisiä lopputiloja ja antavat muun muassa tärkeää tietoa siirtymän hajoamisvakiosta. Tutkimuksessa laskettiin numeerisesti faasiavaruusintegraalit useille tunnetuille beetasiirtymille, jotka voivat olla kaksi- tai useampikertaisesti kiellettyjä. Saatua laskentadataa analysoitiin eri näkökulmista. Tärkein näkökulma on kielletyn uniikin beetasiirtymän ja samaa beetahajoamista kuvaavan perus- eli sallitun siirtymän välinen suhde, koska tämä näkökulma…
Search for Electron-Capture Delayed Fission in the New Isotope 244Md
2020
The electron-capture decay followed by a prompt fission process was searched for in the hitherto unknown most neutron-deficient Md isotope with mass number 244. Alpha decay with α-particle energies of 8.73-8.86 MeV and with a half-life of 0.30_{-0.09}^{+0.19} s was assigned to ^{244}Md. No fission event with a similar half-life potentially originating from spontaneous fissioning of the short-lived electron-capture decay daughter ^{244}Fm was observed, which results in an upper limit of 0.14 for the electron-capture branching of ^{244}Md. Two groups of fission events with half-lives of 0.9_{-0.3}^{+0.6} ms and 5_{-2}^{+3} ms were observed. The 0.9_{-0.3}^{+0.6} ms activity was assigned t…