Nuclear clocks for testing fundamental physics

Peik, E.; Schumm, Thorsten; Safronova, M. S.; Pálffy, Adriana; Weitenberg, Johannes; Thirolf, P.

doi:10.48550/arxiv.2012.09304

Cited by 6 publications

(7 citation statements)

References 4 publications

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“…The 229m Th isomeric state has the lowest excitation energy among all known nuclei. According to the latest data [25] its energy, E is , is 8.19 ± 0.12 eV. This result is close to the value E is = 8.28 ± 0.17 eV obtained in Ref.…”

Section: Introductionsupporting

confidence: 89%

Cross section of the Coulomb excitation of $^{229m}$Th by low energy muons

Tkalya

2021

Preprint

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The inelastic scattering cross section for muons, µ − , with energies E=9-100 eV from the 229 Th nuclei is calculated in the framework of the second order of the perturbation theory for the quantum electrodynamics. The dominant contribution to the excitation of the low energy isomer 229m Th(3/2 + , 8.19 ± 0.12 eV) comes from the E2 multipole. The excitation cross section reaches the value of 10 −21 cm 2 in the range E ≈10 eV. This is four to five orders of magnitude larger than the electron excitation cross section and enough for efficient excitation of 229m Th on the muon beam at the next generation of muon colliders.

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Section: Introductionsupporting

confidence: 89%

Cross section of the Coulomb excitation of $^{229m}$Th by low energy muons

Tkalya

2021

Preprint

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“…Such developments include new methods for optical lattice clocks [100], optical clocks based on highly charged ions and hyperfine transitions [101], etc. A more challenging approach of using nuclear clocks based on long-lived, low-energy isomer 229m Th may allow us to reach a ∼ O(10 −19 )yr −1 sensitivity on frequency [102,103]. To exclude the axi-Higgs model with m a = 3.3 × 10 −29 eV at 95% C.L., the precision of measuring |d(δv)/dt| needs to be 2.2 × 10 −18 yr −1 .…”

Section: Testing the Axi-higgs Modelmentioning

confidence: 99%

Axi-Higgs Cosmology

Fung,

Li,

Liu

et al. 2021

Preprint

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If the Higgs vacuum expectation value v in early universe is ∼ 1% higher than its present value v 0 = 246 GeV, the 7 Li puzzle in BBN and the CMB/ΛCDM tension with late-universe measurements on Hubble parameter are mitigated. We propose a model of an axion coupled to the Higgs field, named "axi-Higgs", with its mass m a ∼ 10 −30 −10 −29 eV and decay constant f a ∼ 10 17 −10 18 GeV, to achieve this goal. The axion initial value a ini yields an initial ∆v ini /v 0 ∼ 0.01 throughout the BBNrecombination epoch and a percent level contribution to the total matter density today. Because of its very large de Broglie wavelength, this axion matter density ω a suppresses the matter power spectrum, alleviating the CMB/ΛCDM S 8 /σ 8 tension with the weak-lensing data. It also explains the recently reported isotropic cosmic birefringence by its coupling with photons. Adding the axion (m ∼ 10 −22 eV) in the fuzzy dark matter model to the axi-Higgs model allows bigger ∆v rec and ω a to address the Hubble and S 8 /σ 8 tensions simultaneously. The model predicts that ∆v may be detected by the spectral measurements of quasars, while its oscillation may be observed in the atomic clock measurements.

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“…This work was also motivated by a need to better understand the Th 3+ properties for the development of the nuclear clock Ref. [10].…”

Section: Introductionmentioning

confidence: 99%

Role of triple excitations in calculating different properties of Ba+

Porsev,

Safronova

2021

Preprint

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We carried out calculations of the energies, hyperfine structure constants and electric-dipole transiton amplitudes for the low-lying states of Ba + in the framework of the relativistic linearized coupled-cluster single double (LCCSD) and coupled-cluster single double (valence) triple (CCSDvT) methods. Taking into account that an iterative inclusion of the valence triples into consideration is a complicated and computationally demanding process we study the effects of computational restriction on the final results. We also present a detailed study of various corrections to all calculated properties and use our results to formulate several broad rules that can be used in future calculations of the elements where experimental data are scarce and correct theoretical predictions are highly important.

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Nuclear clocks for testing fundamental physics

Cited by 6 publications

References 4 publications

Cross section of the Coulomb excitation of $^{229m}$Th by low energy muons

Cross section of the Coulomb excitation of $^{229m}$Th by low energy muons

Axi-Higgs Cosmology

Role of triple excitations in calculating different properties of Ba+

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