Testing fundamental interactions on the helium atom

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10367394" target="_blank" >RIV/00216208:11320/17:10367394 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1103/PhysRevA.95.062510" target="_blank" >http://dx.doi.org/10.1103/PhysRevA.95.062510</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevA.95.062510" target="_blank" >10.1103/PhysRevA.95.062510</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Testing fundamental interactions on the helium atom

Popis výsledku v původním jazyce

We critically examine the current status of theoretical calculations of the energies, the fine structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved discrepancies with experiments. Calculations are performed within the quantum electrodynamics expansion in powers of the fine structure constant a and the electron-to-nucleus mass ratio m/M. For energies, theoretical results are complete through orders alpha(6)m and alpha(6)m(2)/M, with the resulting accuracy ranging from 0.5 to 2 MHz for the n = 2 states. The fine-structure splitting of the 2(3) P state is predicted with a much better accuracy, 1.7 kHz, as a consequence of a calculation of the next-order alpha(7)m effect. An excellent agreement of the theoretical predictions with the recent measurements of the fine structure provides one of the best tests of the bound-state QED in few-electron systems. The isotope shift between He-3 and He-4 is treated with a subkilohertz accuracy, which allows for a high-precision determination of the differences of the nuclear charge radii delta r(2). Several such determinations, however, yield results that are in a 4 sigma disagreement with each other, which remains unexplained. Apart from this, we find no significant discrepancies between theory and experiment for the helium atom. A further calculation of the yet unknown alpha(7)m correction to energy levels will provide a sensitive test of universality in electromagnetic interactions of leptons by comparison of nuclear charge radii obtained by the helium and muonic helium spectroscopy.

Název v anglickém jazyce

Testing fundamental interactions on the helium atom

Popis výsledku anglicky

We critically examine the current status of theoretical calculations of the energies, the fine structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved discrepancies with experiments. Calculations are performed within the quantum electrodynamics expansion in powers of the fine structure constant a and the electron-to-nucleus mass ratio m/M. For energies, theoretical results are complete through orders alpha(6)m and alpha(6)m(2)/M, with the resulting accuracy ranging from 0.5 to 2 MHz for the n = 2 states. The fine-structure splitting of the 2(3) P state is predicted with a much better accuracy, 1.7 kHz, as a consequence of a calculation of the next-order alpha(7)m effect. An excellent agreement of the theoretical predictions with the recent measurements of the fine structure provides one of the best tests of the bound-state QED in few-electron systems. The isotope shift between He-3 and He-4 is treated with a subkilohertz accuracy, which allows for a high-precision determination of the differences of the nuclear charge radii delta r(2). Several such determinations, however, yield results that are in a 4 sigma disagreement with each other, which remains unexplained. Apart from this, we find no significant discrepancies between theory and experiment for the helium atom. A further calculation of the yet unknown alpha(7)m correction to energy levels will provide a sensitive test of universality in electromagnetic interactions of leptons by comparison of nuclear charge radii obtained by the helium and muonic helium spectroscopy.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10300 - Physical sciences

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review A

ISSN

2469-9926

e-ISSN

—

Svazek periodika

95

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

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Kód UT WoS článku

000404461300005

EID výsledku v databázi Scopus

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