Measuring the neutron lifetime using magnetically trapped neutrons

O’Shaughnessy, C.; Golub, R.; Schelhammer, K.W.; Swank, Christopher; Seo, P. N.; Huffman, P. R.; Dzhosyuk, S. N.; Mattoni, C. E. H.; Yang, L.; Doyle, John M.; Coakley, Kevin J.; Thompson, A. K.; Mumm, H. P.; Lamoreaux, S. K.; McKinsey, D. N.; Yang, Grace L.

doi:10.1016/j.nima.2009.07.054

Cited by 19 publications

(9 citation statements)

References 15 publications

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“…In 2000, a magnetic trapping experiment at NIST used a quadrupole trap defined by a set of superconducting coils [216][217][218]. It measured neutron decays in situ by detecting the decay electrons in superfluid 4 He at a temperature near 300 mK.…”

Section: Neutron Lifetimementioning

confidence: 99%

New physics searches in nuclear and neutron β decay

González–Alonso

Naviliat‐Cuncic

Severijns

2019

Progress in Particle and Nuclear Physics

239

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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Section: Neutron Lifetimementioning

confidence: 99%

New physics searches in nuclear and neutron β decay

González–Alonso

Naviliat‐Cuncic

Severijns

2019

Progress in Particle and Nuclear Physics

239

282

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“…The simplest form of the Ioffe-Pritchard trap is a quadrupole magnet with pinch coils at either end, and it has been successfully used to trap hydrogen atoms [279] and free neutrons [280].…”

Section: B Frequency Techniquesmentioning

confidence: 99%

Direct Measurements of Neutrino Mass

Formaggio,

de Gouvêa,

Robertson

2021

Preprint

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The turn of the 21st century witnessed a sudden shift in our fundamental understanding of particle physics. While the minimal Standard Model predicts that neutrino masses are exactly zero, the discovery of neutrino oscillations proved the Standard Model wrong. Neutrino oscillation measurements, however, do not shed light on the scale of neutrino masses, nor the mechanism by which those are generated. The neutrino mass scale is most directly accessed by studying the energy spectrum generated by beta decay or electron capture -a technique dating back to Enrico Fermi's formulation of radioactive decay. In this Article, we review the methods and techniques -both past and present -aimed at measuring neutrino masses kinematically. We focus on recent experimental developments that have emerged in the past decade, overview the spectral refinements that are essential in the treatment of the most sensitive experiments, and give a simple yet effective protocol for estimating the sensitivity. Finally, we provide an outlook of what future experiments might be able to achieve. Contents I. Introduction II. Neutrino Masses: Current Status A. Neutrino oscillations B. Neutrinoless double beta decay C. Cosmology D. Neutrinos from Astrophysical Sources -Time of Flight

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“…To achieve the low temperatures required for a superfluidhelium converter, the first attempts at KEK [16] converted a cold-neutron beam to ultracold neutrons to reduce the heat load and therefore required no moderators. This concept is now in operation for a source at Institut Laue-Langevin [17] but can also be used to produce ultracold neutrons directly in an experiment cell [18,19]. These sources are limited by the lower intensities of collimated neutron beams, but concepts that could reach production rates similar to the planned source at TRIUMF at significantly lower heat loads have been proposed [20].…”

Section: Introductionmentioning

confidence: 99%

Optimizing neutron moderators for a spallation-driven ultracold-neutron source at TRIUMF

Schreyer

Davis

Kawasaki

et al. 2020

Nuclear Instruments and Methods in Physics Research Section A:

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We report on our efforts to optimize the geometry of neutron moderators and converters for the TRIUMF UltraCold Advanced Neutron (TUCAN) source using MCNP simulations. It will use an existing spallation neutron source driven by a 19.3 kW proton beam delivered by TRIUMF's 520 MeV cyclotron. Spallation neutrons will be moderated in heavy water at room temperature and in liquid deuterium at 20 K, and then superthermally converted to ultracold neutrons in superfluid, isotopically purified 4 He. The helium will be cooled by a 3 He fridge through a 3 He-4 He heat exchanger.The optimization took into account a range of engineering and safety requirements and guided the detailed design of the source. The predicted ultracold-neutron density delivered to a typical experiment is maximized for a production volume of 27 L, achieving a production rate of 1.4 · 10 7 s −1 to 1.6 · 10 7 s −1 with a heat load of 8.1 W. At that heat load, the fridge can cool the superfluid helium to 1.1 K, resulting in a storage lifetime for ultracold neutrons in the source of about 30 s. The most critical performance parameters are the choice of cold moderator and the volume, thickness, and material of the vessel containing the superfluid helium.The source is scheduled to be installed in 2021 and will enable the TUCAN collaboration to measure the electric dipole moment of the neutron with a sensitivity of 10 −27 e cm.

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Measuring the neutron lifetime using magnetically trapped neutrons

Cited by 19 publications

References 15 publications

New physics searches in nuclear and neutron β decay

New physics searches in nuclear and neutron β decay

Direct Measurements of Neutrino Mass

Optimizing neutron moderators for a spallation-driven ultracold-neutron source at TRIUMF

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