Vacuum Polarization and Positronium-Ground-State Splitting

Barbieri, Riccardo; Christillin, P.; Remiddi, E.

doi:10.1103/physreva.8.2266

Cited by 53 publications

(40 citation statements)

References 9 publications

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“…The pure O(mα 6 ) terms were an even greater challenge, partly because there are so many separate contributions to calculate, partly because some of them required the use of methods that weren't yet developed when work on these terms commenced in 1973. It took a quarter of a century for work on C 20 to be successfully completed with contributions from many workers [30,33,. The analytic result C 20 = − 648 was obtained two years after the first correct numerical value [61].…”

Section: Introductionmentioning

confidence: 99%

“…Early attempts to obtain the two-loop logarithmic corrections, starting in 1970, were incorrect or incomplete because of awkward bound state formalisms and because the origins of the logs were not at first understood. Many groups contributed to the successful calculation of C 21 [27][28][29][30][31][32][33][34]. The correct result, C 21 = 5 24 , was obtained by Lepage in 1977 and was quickly confirmed [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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Positronium hyperfine splitting at ordermα7: Light-by-light scattering in the two-photon-exchange channel

Adkins

Fell

2014

Phys. Rev. A

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We have calculated the contribution to the positronium hyperfine splitting at order mα 7 of the light-by-light scattering process in the exchange of two photons between the electron and positron. Our result is ∆E = −0.235355(8)mα 4 α π 3 = −1.034kHz. As a check of our approach we confirm earlier evaluations of the analogous correction for a bound system (such as muonium) with unequal masses.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Positronium hyperfine splitting at ordermα7: Light-by-light scattering in the two-photon-exchange channel

Adkins

Fell

2014

Phys. Rev. A

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“…The one-loop vacuum polarization factor is easy to obtain by direct calculation. The two-loop correction was worked out by Barbieri et al [90] and by Samuel [91]. The zero-, one-, and two-loop scattering amplitudes are shown in Fig.…”

Section: B Calculation Of the Scattering Amplitude Via Qedmentioning

confidence: 99%

Two-Loop Correction to the Orthopositronium Decay Rate

2002

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We give a detailed description of our calculation of the O(α 2 ) correction to the orthopositronium decay rate. The resulting correction is 45.06(26) in units of (α/π) 2 times the lowest order rate. When combined with other known corrections, the theoretical prediction for the decay rate is 7.039979(11) µs −1 , where the leading uncalculated term makes an estimated contribution of roughly 0.00002 µs −1 . Our result is in significant disagreement with two of the four highest precision measurements (at about the 5σ level), but does not contradict the others. The experimental uncertainties (≈0.002 µs −1 ) are much larger than the remaining theoretical uncertainties. We also calculate the one-photon-annihilation contribution to the positronium hyperfine structure at O(mα 6 ). This calculation is closely analogous to the decay rate calculation. Our agreement with prior results for this hyperfine structure contribution demonstrates the soundness of our approach. C 2002 Elsevier Science (USA)

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“…Отметим, что ресуммирующие факторы появляются в параметризации мнимой части соответствующих кварковых токовых корреляторов, в отношении Дрелла R(s), которое в двухчастичном приближении может быть аппроксимировано ам-плитудой Бете-Солпитера двух заряженных частиц χ BS (x) при x = 0 [50]. Пред-ставление амплитуды Бете-Солпитера через волновую функцию, отвечающую нере-лятивистскому уравнению Шредингера с кулоновским потенциалом, ведет к форму-ле (1.3) с заменой α → 4α s /3 для КХД.…”

Section: )unclassified