14 research outputs found
Search for Superscreening effect in Superconductor
4 pages, 3 figures, Expérience au GANIL avec SPIRAL/EXOGAMThe decay of O() and Ne() implanted in niobium in its superconducting and metallic phase was measured using purified radioactive beams produced by the SPIRAL/GANIL facility. Half-lives and branching ratios measured in the two phases are consistent within one-sigma error bar. This measurement casts strong doubts on the predicted strong electron screening in superconductor, the so-called superscreening. The measured difference in screening potential energy is 110(90) eV for Ne and 400(320) eV for O. Precise determinations of the half-lives were obtained for O: 26.476(9)~s and Ne: 17.254(5)~s
Electric dipole moments and the search for new physics
Static electric dipole moments of nondegenerate systems probe mass scales for
physics beyond the Standard Model well beyond those reached directly at high
energy colliders. Discrimination between different physics models, however,
requires complementary searches in atomic-molecular-and-optical, nuclear and
particle physics. In this report, we discuss the current status and prospects
in the near future for a compelling suite of such experiments, along with
developments needed in the encompassing theoretical framework.Comment: Contribution to Snowmass 2021; updated with community edits and
endorsement
Transmission of Muons in an Alternating Gradient Funneling System
One important issue in a neutrino factory is the target system for pion production. The A.G. funneling system addressed here consists of four horns, with 1 MW target per horn, followed by a recombination A.G. channel and a FODO decay channel. The transmission of this scheme is analyzed in detail. It is compared with that of a simple solenoid for several sets of optics parameters. This study makes it possible to gain in transmission efficiency in comparison with earlier proposals
6-D BEAM DYNAMICS IN AN ISOCHRONOUS FFAG RING
Numerical ray-tracing tools for 6-D tracking in FFAG accelerators have been developed. They are applied to the simulation of muon acceleration in the newly introduced isochronous type of FFAG ring designed for 16-turn, 8 to 20~GeV muon acceleration in the Neutrino Factory
g-factor measurement of the 9/2+ isomeric state in 65Ni
We report on the first measurement of the g factor of the Jpi = 9/2+ isomeric state in Ni. (d,p) reactions on enriched Ni and 62Ni have been used in order to populate and spin orient the Jpi = 9/2+ isomeric states in 65Ni and 63Ni. The hyperfine field of the Ni target, oriented by an external magnetic field, was used in order to obtain a sufficient number of spin precessions within the relatively short life time of the isomers. The g factor obtained, g65mNi = -0.296(3), is in good agreement with the g factors of other 9/2+states in the region and with shell-model calculations
The EMMA Non-scaling FFAG
The Electron Model for Many Applications (EMMA) will be the World's first non-scaling FFAG and is under construction at the STFC Daresbury Laboratory in the UK. Construction is due for completion in March 2010 and will be followed by commissioning with beam and a detailed experimental programme to study the functioning of this type of accelerator. This paper will give an overview of the motivation for the project and describe the EMMA design and hardware. The first results from commissioning will be presented in a separate paper
Astrophysical(, ) reaction in inverse kinematics; Electron screening effect in the beta-decay
International audienceThe abundance calculations of the p-nuclei produced in explosive stellar sites rely on the Hauser-Feshbach (HF) theory with the alpha-article optical model potential (α-OMP) one of its major ingredients. To date, most of the (α, γ) cross sections measured show that HF calculations can be wrong by a factor of ten or more especially when phenomenological α-OMP are employed. To investigate the relevant uncertainties entering the HF calculations and furthermore develop global microscopic α-OMPs, systematic (α, γ) cross-section measurements are necessary. This led us to perform a feasibility study of (α, γ) measurements in inverse kinematics that will allow us to employ also radioactive beams in the future. Hence, the 4He(78Kr,γ)82Sr reaction was studied using the LISE3 spectrometer to separate the 82Sr recoils from the primary 78Kr beam. Although an excellent rejection factor > 1010 was achieved, the position of the ions of interest was unexpectedly masked by a secondary beam of high intensity. Given these, new setup improvements are proposed to remove the pollutant ions. Recently, many experiments were conducted in order to study the influence of the environment (especially in a metallic material) on the decay probability of radioactive nuclei. Additionally, hydrogen-like fusion reactions were performed indicating a change in the cross-section due to the influence of the Coulomb field screening induced by quasi-free electrons in metals. This was explained by the Debye screening model which treats metallic electrons within Maxwell-Boltzmann statistics. We measured the decay rate of 19O in metallic, insulating and superconducting environments whereas the electrons in the superconductors should obey the Bose-Einstein statistics. The decay rate measurement was supported by a branching ratios measurement. We found that the effect on the decay rate, if any, is less than the 0.1%, far below the theoretical predictions