Physics

Special Issue Editors

Dr. Savely G. Karshenboim

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Guest Editor

1. Department of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799 Munich, Germany
2. Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching, Germany
Interests: precision physics of simple atomic systems; fundamental constants

Prof. Dr. Eberhard Widmann

E-Mail Website
Guest Editor

Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Kegelgasse 27, 1030 Vienna, Austria
Interests: low-energy precision tests of the standard model of particle physics; precision spectroscopy of antiprotonic atoms; antihydrogen and ultra-cold hydrogen to study CPT symmetry; lorentz invariance and QED

Special Issue Information

Dear Colleagues,

In this Special Issue, selected papers from the International Conference on Precision Physics and Fundamental Physical Constants (FFK 2023, https://indico.cern.ch/event/1164804/, 22‒26 May 2023) are presented. FFK 2023 followed the rich traditions of the previous seminars and conferences, covering the recent progress in the field.

The presentations spanned a wide range of topics, from classical metrology; the realisation of the kilogramme, through precision spectroscopy of electronic and exotic atoms; as well as molecules to determine masses and magnetic moments of elementary particles; electric dipole measurements; and mass measurements to particle physics aspects such as precision measurements of the neutron, the CKM matrix, recent developments in the theory of muon g‒2, and collider searches for beyond-the-standard-model physics.

FFK 2023 was endorsed by CODATA Task group on fundamental constants.

Although this Special Issue collaborates with the International Conference on Precision Physics and Fundamental Physical Constants (FFK 2023), all relevant manuscripts are welcome, including research and review articles.

Dr. Savely G. Karshenboim
Prof. Dr. Eberhard Widmann
Guest Editors

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Keywords

fundamental constants
precision experiments
hydrogen atom and molecule
muonium
antihydrogen
EDMs
mass and g-factors measurements in traps
muon g‒2
CKM matrix

Published Papers (3 papers)

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Research

Jump to: Review

14 pages, 1690 KiB

Open AccessArticle

Present Status of Spectroscopy of the Hyperfine Structure and Repolarization of Muonic Helium Atoms at J-PARC

by Seiso Fukumura, Patrick Strasser, Mahiro Fushihara, Yu Goto, Takashi Ino, Ryoto Iwai, Sohtaro Kanda, Shiori Kawamura, Masaaki Kitaguchi, Shoichiro Nishimura, Takayuki Oku, Takuya Okudaira, Hirohiko M. Shimizu, Koichiro Shimomura, Hiroki Tada and Hiroyuki A. Torii

Physics 2024, 6(2), 877-890; https://doi.org/10.3390/physics6020054 - 12 Jun 2024

Viewed by 253

Abstract

The mass

m_{μ^{-}}

of the negative muon is one of the parameters of the elementary particle Standard Model and it allows us to verify the CPT (charge–parity–time) symmetry theorem by comparing

m_{μ^{-}}

value with the mass

m_{μ^{+}}

[...] Read more.

The mass

m_{μ^{-}}

of the negative muon is one of the parameters of the elementary particle Standard Model and it allows us to verify the CPT (charge–parity–time) symmetry theorem by comparing

m_{μ^{-}}

value with the mass

m_{μ^{+}}

of the positive muon. However, the experimental determination precision of

m_{μ^{-}}

3.1 ppm

, which is an order of magnitude lower than the determination precision of

m_{μ^{+}}

120 ppb

. The authors aim to determine

m_{μ^{-}}

and the magnetic moment

μ_{μ^{-}}

with a precision of

O (10 ppb)

through spectroscopy of the hyperfine structure (HFS) of muonic helium-4 atom

(^{4} He μ^{-} e^{-})

under high magnetic fields.

{}^{4}{He} μ^{-} e^{-}

is an exotic atom where one of the two electrons of the

{}^{4}{He}

atom is replaced by a negative muon. To achieve the goal, it is necessary to determine the HFS of

{}^{4}{He} μ^{-} e^{-}

with a precision of

O (1 ppb)

. This paper describes the determination procedure of the HFS of

{}^{4}{He} μ^{-} e^{-}

in weak magnetic fields reported recently, and the work towards achieving the goal of higher precision measurement. Full article

(This article belongs to the Special Issue Precision Physics and Fundamental Physical Constants (FFK 2023))

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Figure 1

10 pages, 305 KiB

Open AccessEditor’s ChoiceCommunication

Towards Precision Muonic X-ray Measurements of Charge Radii of Light Nuclei

by Ben Ohayon, Andreas Abeln, Silvia Bara, Thomas Elias Cocolios, Ofir Eizenberg, Andreas Fleischmann, Loredana Gastaldo, César Godinho, Michael Heines, Daniel Hengstler, Guillaume Hupin, Paul Indelicato, Klaus Kirch, Andreas Knecht, Daniel Kreuzberger, Jorge Machado, Petr Navratil, Nancy Paul, Randolf Pohl, Daniel Unger, Stergiani Marina Vogiatzi, Katharina von Schoeler and Frederik Wauters Show full author list Hide full author list

Physics 2024, 6(1), 206-215; https://doi.org/10.3390/physics6010015 - 17 Feb 2024

Cited by 5 | Viewed by 758

Abstract

We, the QUARTET Collaboration, propose an experiment to measure the nuclear charge radii of light elements with up to 20 times higher accuracy. These are essential both for understanding nuclear physics at low energies, and for experimental and theoretical applications in simple atomic systems. Such comparisons advance the understanding of bound-state quantum electrodynamics and are useful for searching for new physics beyond the Standard Model. The energy levels of muonic atoms are highly susceptible to nuclear structure, especially to the mean square charge radius. The radii of the lightest nuclei (with the atomic number,

Z = 1, 2

) have been determined with high accuracy using laser spectroscopy in muonic atoms, while those of medium mass and above were determined using X-ray spectroscopy with semiconductor detectors. In this communication, we present a new experiment, aiming to obtain precision measurements of the radii of light nuclei

3 \leq Z \leq 10

using single-photon energy measurements with cryogenic microcalorimeters; a quantum-sensing technology capable of high efficiency with outstanding resolution for low-energy X-rays. Full article

(This article belongs to the Special Issue Precision Physics and Fundamental Physical Constants (FFK 2023))

Review

Jump to: Research

14 pages, 1844 KiB

Open AccessReview

Avogadro and Planck Constants, Two Pillars of the International System of Units

by Enrico Massa

Physics 2024, 6(2), 845-858; https://doi.org/10.3390/physics6020052 - 3 Jun 2024

Viewed by 180

Abstract

The International System of Units (SI), the current form of the metric system and the world’s most used system of units, has been continuously updated and refined since the Metre Convention of 1875 to ensure that it remains up to date with the latest scientific and technological advances. The General Conference on Weights and Measures, at its 26th meeting in 2018, decided to adopt stipulated values of seven physical constants linked to seven measurement units (the second, meter, kilogram, ampere, kelvin, mole, and candela). This paper reviews the technologies developed, in intense and long-standing work, to determine the Avogadro and Planck constants, which are now integral to realising the kilogram. Full article

(This article belongs to the Special Issue Precision Physics and Fundamental Physical Constants (FFK 2023))

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