Forbidden (slow) β decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and ...reinterpret the only two relevant experiments, performed in the 1970s, dedicated to search for a preferred direction in space in first- and second-forbidden β decays. We show that the results of these experiments put strong and unique limits on Lorentz violation, and in particular on the presence of several interactions in the modern Lorentz-violating standard model extension. We discuss prospects to improve on these limits.
Question of Lorentz violation in muon decay Noordmans, J. P.; Onderwater, C. J. G.; Wilschut, H. W. ...
Physical review. D,
06/2016, Letnik:
93, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the direction-dependent muon-decay rate with a general Lorentz-violating addition to the ...W-boson propagator. We discuss measurements of the directional and boost dependence of the Michel parameters and of the muon lifetime as a function of absolute velocity. The total muon-decay rate in the Lorentz-violating standard model extension is addressed. Suggestions are made for dedicated (re)analyses of the pertinent data and for future experiments.
The possibility of violation of rotational invariance in
β
decay is considered. Such violation would imply Lorentz invariance violation. Recent developments in experiment and theory are discussed.
A rotating target for Ra production Sohani, M.; Wilschut, H.W.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2012, Letnik:
679
Journal Article
Recenzirano
A target wheel with pyrolytic graphite targets is designed and constructed at the TRIμP facility to boost the production rate of Ra isotopes. Simulation, design properties and production results are ...discussed.
The paper analyses and compares developments in history teaching in Germany, England, and the Netherlands in the 19th and 20th centuries. The development of history teaching in the three countries ...shows striking similarities. National politics have always used history education for purposes which did not necessarily tally with distanced critical thinking, carefully balanced judgements, and a striving for unbiased interpretations. In the two centuries described here, only the decades of the 1960s and 1970s have been different. Then politics and society scorned a subject which was so clearly unfit for a 'modern age'. Attempts were made to eliminate history from the school curriculum. As a consequence, history educators adopted a defensive position and a new type of history teaching emerged, which put critical and distanced thinking at the centre. Because politics had turned its back on history, it was possible to develop a vision of history teaching which did not serve any preconceived political aim but took historical thinking as such as its point of departure. During the 1980s and 1990s, the old recipe of forging nations was revived and traditional curricula were once more brought to life.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A single Ra
+
ion stored in a Paul radio frequency ion trap has excellent potential for a precision measurement of the electroweak mixing angle at low momentum transfer and as the most stable optical ...clock. The effective transport and cooling of singly charged ions of the isotopes
209
Ra to
214
Ra in a gas filled radio frequency quadrupole device is reported. The absolute frequencies of the transition 7s
2
S
1/2
–7d
2
D
3/2
at wavelength 828 nm have been determined in
212–214
Ra
+
with ≤19 MHz uncertainty using laser spectroscopy on small samples of ions trapped in a linear Paul trap at the online facility Trapped Radioactive Isotopes: µicrolaboratories for fundamental Physics (TRIµP) of the Kernfysisch Versneller Instituut.
Two complementary experimental techniques have been used to extract precise branching ratios to unbound states in 12C from 12N and 12B β-decays. In the first the three α-particles emitted after ...β-decay are measured in coincidence in separate detectors, while in the second method 12N and 12B are implanted in a detector and the summed energy of the three α-particles is measured directly. For the narrow states at 7.654 MeV (0+) and 12.71 MeV (1+) the resulting branching ratios are both smaller than previous measurements by a factor of ≃2. The experimental results are compared to no-core shell model calculations with realistic interactions from chiral perturbation theory, and inclusion of three-nucleon forces is found to give improved agreement.
A measurement of the final state distribution of the (8)B β decay, obtained by implanting a (8)B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent ...with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyväskylä O. S. Kirsebom et al., Phys. Rev. C 83, 065802 (2011). It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.
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