Half-life of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Fr</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>221</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>in Si and Au at 4 K and at millikelvin temperatures

Wauters, F.; Verstichel, Brecht; Breitenfeldt, M.; Leebeeck, V. De; Козлов, В.; Kraev, I. S.; Roccia, S.; Soti, G.; Tandecki, M.; Traykov, E.; Gorp, S. Van; Zákoucký, D.; Severijns, N.

doi:10.1103/physrevc.82.064317

Cited by 11 publications

(10 citation statements)

References 36 publications

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“…As we have verified, differences in the values of the chemical potential calculated in calculated at a given η in different matrices (i.e., the fractional halflife difference between two matrices) must be much smaller than 10 -3 , for 3 < η . This conclusion is in line with precise half-life measurements on 221 Fr implanted into matrices of Si and Au at ordinary density [37].…”

Section: Extension To Matrices Of Other Elements and Implications Forsupporting

confidence: 84%

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

Belloni

2016

Eur. Phys. J. A

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The influence of the electron environment on the α decay is elucidated. Within the frame of a simple model based on the generalized Thomas-Fermi theory of the atom, it is shown that the increase of the electron density around the parent nucleus drives a mechanism which shortens the lifetime. Numerical results are provided for 144 Nd, 154 Yb and 210 Po. Depending on the nuclide, fractional lifetime reduction relative to the bare nucleus is of the order of 0.1÷1% in free ions, neutral atoms and ordinary matter, but may reach up to 10% at matter densities as high as 10 4 g/cm 3 , in a high-Z matrix. The effect induced by means of state-of-the-art compression techniques, although much smaller than previously found, would however be measurable. The extent of the effect in ultra-high-density stellar environments might become significant and would deserve further investigation.

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Section: Extension To Matrices Of Other Elements and Implications Forsupporting

confidence: 84%

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

Belloni

2016

Eur. Phys. J. A

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“…(7a). 9 Since its contribution to the observables is now reaching the same order of magnitude as the experimental precision (∼ 0.1 − 1.0%) [71][72][73][74][75][76][77][78], the effect of weak magnetism in nuclei has to be sufficiently well understood [79]. This is not a problem for three classes of transitions: (i) superallowed pure Fermi β decays, where weak magnetism is absent; (ii) the neutron and mixed F/GT mirror β transitions, all occurring between members of an isospin doublet, where the weak magnetism contribution is given by CVC in terms of the nuclear magnetic moments of the two analog states connected by the β transition [28,80]; and (iii) for β transitions from states that are part of a T = 1 multiplet decaying to T = 0 states, such as the 6 He decay, since in this case weak magnetism is related by CVC to the M1 transition strength of the γ decay analog to the β transition [27,28,80].…”

Section: Nucleus-level Eft (M Fgt Cmentioning

confidence: 95%

“…They offer well-localized and cooled samples of particles in vacuum, that can often even be purified in situ. They also permit almost undisturbed observation of the recoil ions, and reduce significantly the effects of scattering for β particles, which is usually limiting experiments with radioactive sources embedded in a material [74,75]. The β-ν correlation measurements in nuclear decays that we include in the fits described in Section 4 are listed in Table 6.…”

Section: β − ν Correlationmentioning

confidence: 99%

New physics searches in nuclear and neutron β decay

González–Alonso

Naviliat‐Cuncic

Severijns

2019

Progress in Particle and Nuclear Physics

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282

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The status of tests of the standard electroweak model and of searches for new physics in allowed nuclear β decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and complementarity of recent and ongoing experiments are discussed with emphasis on their potential to look for new physics. Measurements are interpreted using a model-independent effective field theory approach enabling to recast the outcome of the analysis in many specific new physics models. Special attention is given to the connection that this approach establishes with high-energy physics. A new global fit of available β-decay data is performed incorporating, for the first time in a consistent way, superallowed 0 + → 0 + transitions, neutron decay and nuclear decays. The constraints on exotic scalar and tensor couplings involving left-or right-handed neutrinos are determined while a constraint on the pseudoscalar coupling from neutron decay data is obtained for the first time as well. The values of the vector and axial-vector couplings, which are associated within the standard model to V ud and g A respectively, are also updated. The ratio between the axial and vector couplings obtained from the fit under standard model assumptions is C A /C V = −1.27510(66). The relevance of the various experimental inputs and error sources is critically discussed and the impact of ongoing measurements is studied. The complementarity of the obtained bounds with other low-and high-energy probes is presented including ongoing searches at the Large Hadron Collider.

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“…Figure 1 shows all the relevant decay paths to 221 Fr, and its subsequent α decay to 217 At. The half-life of 221 Fr is t 1/2 = 288.0(4) s, based on a weighted average of values found in [18,19,20]. An 225 Ac source has a half-life of 9.920(3) days [21], and a 221 Fr rate which is initially 8.0 · 10 −7 of the implanted 225 Ac amount.…”

Section: Methodsmentioning

confidence: 99%

Offline trapping of²²¹Fr in a magneto-optical trap from implantation of an²²⁵Ac ion beam

et al. 2014

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We demonstrate a new technique to prepare an offline source of francium for trapping in a magneto-optical trap. Implanting a radioactive beam of 225 Ac, t 1/2 = 9.920(3) days, in a foil, allows use of the decay products, i.e. 221 Fr, t 1/2 = 288.0(4) s. 221 Fr is ejected from the foil by the α decay of 225 Ac. This technique is compatible with the online accumulation of a lasercooled atomic francium sample for a series of planned parity non-conservation measurements at TRIUMF. We obtain a 34 % release efficiency for 221 Fr from the recoil source based on particle detector measurements. We find that laser cooling operation with the source is 8 +10 −5 times less efficient than from a mass-separated ion beam of 221 Fr in the current geometry. While the flux of this source is two to three orders of magnitude lower than typical francium beams from ISOL facilities, the source provides a longer-term supply of francium for offline studies.

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Half-life ofFr221in Si and Au at 4 K and at millikelvin temperatures

Cited by 11 publications

References 36 publications

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

New physics searches in nuclear and neutron β decay

Offline trapping of²²¹Fr in a magneto-optical trap from implantation of an²²⁵Ac ion beam

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Half-life ofFr221in Si and Au at 4 K and at millikelvin temperatures

Cited by 11 publications

References 36 publications

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

Alpha decay in electron environments of increasing density: From the bare nucleus to compressed matter

New physics searches in nuclear and neutron β decay

Offline trapping of221Fr in a magneto-optical trap from implantation of an225Ac ion beam

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Product

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Offline trapping of²²¹Fr in a magneto-optical trap from implantation of an²²⁵Ac ion beam