60 research outputs found
Probing the nuclide 180W for neutrinoless double-electron capture exploration
The mass difference of the nuclides 180W and 180Hf has been measured with the
Penning-trap mass spectrometer SHIPTRAP to investigate 180W as a possible
candidate for the search for neutrinoless doubleelectron capture. The Q-value
was measured to 143.20(27)keV. This value in combination with the calculations
of the atomic electron wave functions and other parameters results in a
half-life of the 0+ \rightarrow 0+ ground-state to ground-state double-electron
capture transition of approximately 5\cdot10E27 years/^2
Recent advances in neutrinoless double beta decay search
Even after the discovery of neutrino flavour oscillations, based on data from
atmospheric, solar, reactor, and accelerator experiments, many characteristics
of the neutrino remain unknown. Only the neutrino square-mass differences and
the mixing angle values have been estimated, while the value of each mass
eigenstate still hasn't. Its nature (massive Majorana or Dirac particle) is
still escaping. Neutrinoless double beta decay (-DBD) experimental
discovery could be the ultimate answer to some delicate questions of elementary
particle and nuclear physics. The Majorana description of neutrinos allows the
-DBD process, and consequently either a mass value could be measured or
the existence of physics beyond the standard should be confirmed without any
doubt. As expected, the -DBD measurement is a very difficult field of
application for experimentalists. In this paper, after a short summary of the
latest results in neutrino physics, the experimental status, the R&D projects,
and perspectives in -DBD sector are reviewed.Comment: 36 pages, 7 figures, To be publish in Czech Journal of Physic
Double Beta Decay
We review recent developments in double-beta decay, focusing on what can be
learned about the three light neutrinos in future experiments. We examine the
effects of uncertainties in already measured neutrino parameters and in
calculated nuclear matrix elements on the interpretation of upcoming
double-beta decay measurements. We then review a number of proposed
experiments.Comment: Some typos corrected, references corrected and added. A less blurry
version of figure 3 is available from authors. 41 pages, 5 figures, submitted
to J. Phys.
Double beta decay: present status
The present status of double beta decay experiments (including the search for
, EC and ECEC processes) are reviewed. The results of
the most sensitive experiments are discussed. Average and recommended half-life
values for two-neutrino double beta decay are presented. Conservative upper
limits on effective Majorana neutrino mass and the coupling constant of the
Majoron to the neutrino are established as eV and , respectively. Proposals for future double beta decay
experiments with a sensitivity for the at the level of (0.01-0.1)
eV are considered.Comment: 33 pages included 7 figures and 14 tables; an extended version of the
invited talk at 13th Lomonosov Conference of Elementary Particle Physics,
23-29 August, 2007, Moscow, Russi
Searching for Majorana neutrinos with double beta decay and with beta beams
The leading questions in today neutrino physics concern the transformation properties of neutrinos under charge conjugation, the lepton number conservation hypothesis and the values of neutrino masses. The answers can be obtained if the neutrinoless double beta decay, 0ν2β, is observed and its rate is measured. The mere observation of the process proves the Majorana nature of neutrinos as well as the violation of the lepton number conservation, while the rate is a sensitive measure of the neutrino mass. The search for this effect at present concerns mainly the double β- decay. This paper describes the recent proposal to search for the neutrinoless radiative double electron capture as an attractive alternative to the double β- decay. It is shown, moreover, that the same information which is expected from the 0ν2β studies can in principle be also obtained from experiments using intense νe beams produced by radioactive ions decaying in flight (the âbeta beamsâ)
<i>Drosophila</i> as a Model of Unconventional Translation in Spinocerebellar Ataxia Type 3
RNA toxicity contributes to diseases caused by anomalous nucleotide repeat expansions. Recent work demonstrated RNA-based toxicity from repeat-associated, non-AUG-initiated translation (RAN translation). RAN translation occurs around long nucleotide repeats that form hairpin loops, allowing for translation initiation in the absence of a start codon that results in potentially toxic, poly-amino acid repeat-containing proteins. Discovered in Spinocerebellar Ataxia Type (SCA) 8, RAN translation has been documented in several repeat-expansion diseases, including in the CAG repeat-dependent polyglutamine (polyQ) disorders. The ATXN3 gene, which causes SCA3, also known as MachadoâJoseph Disease (MJD), contains a CAG repeat that is expanded in disease. ATXN3 mRNA possesses features linked to RAN translation. In this paper, we examined the potential contribution of RAN translation to SCA3/MJD in Drosophila by using isogenic lines that contain homomeric or interrupted CAG repeats. We did not observe unconventional translation in fly neurons or glia. However, our investigations indicate differential toxicity from ATXN3 protein-encoding mRNA that contains pure versus interrupted CAG repeats. Additional work suggests that this difference may be due in part to toxicity from homomeric CAG mRNA. We conclude that Drosophila is not suitable to model RAN translation for SCA3/MJD, but offers clues into the potential pathogenesis stemming from CAG repeat-containing mRNA in this disorder
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