| 1. |
- Aoyama, T., et al.
(author)
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The anomalous magnetic moment of the muon in the Standard Model
- 2020
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In: Physics reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 887, s. 1-166
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Research review (peer-reviewed)abstract
- We review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant α and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including O(α5) with negligible numerical uncertainty. The electroweak contribution is suppressed by (mμ/MW)2 and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at O(α2) and is due to hadronic vacuum polarization, whereas at O(α3) the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads aμSM = 116 591 810(43) x 10-11 and is smaller than the Brookhaven measurement by 3.7 σ. The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future - which are also discussed here - make this quantity one of the most promising places to look for evidence of new physics.
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| 2. |
- Adlarson, Patrik, et al.
(author)
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Measurement of the ω → π+π−π0 Dalitz plot distribution : The WASA-at-COSY Collaboration
- 2017
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 770, s. 418-425
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Journal article (peer-reviewed)abstract
- Using the production reactions pd -> He-3 omega and pp -> pp omega, the Dalitz plot distribution for the omega -> pi(+)pi(-)pi(0)decay is studied with the WASA detector at COSY, based on a combined data sample of (4.408 +/- 0.042) x 10(4) events. The Dalitz plot density is parametrised by a product of the P-wave phase space and a polynomial expansion in the normalised polar Dalitz plot variables Z and phi. For the first time, a deviation from pure P-wave phase space is observed with a significance of 4.1 sigma. The deviation is parametrised by a linear term 1+2 alpha Z, with alpha determined to be +0.147 +/- 0.036, consistent with the expectations of rho-meson-type final-state interactions of the P-wave pion pairs. (C) 2017 The Author. Published by Elsevier B.V.
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| 3. |
- Hanhart, C., et al.
(author)
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The branching ratio omega -> pi(+) pi(-) revisited
- 2017
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:2
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Journal article (peer-reviewed)abstract
- We analyze themost recent data for the pion vector form factor in the timelike region, employing a modelindependent approach based on dispersion theory. We confirm earlier observations about the inconsistency of different modern high-precision data sets. Excluding the BaBar data, we find an updated value for the isospin-violating branching ratio B(omega -> pi(+) pi(-)) = (1.46 +/- 0.08) x 10(-2). As a side result, we also extract an improved value for the pion vector or charge radius, root < r(V)(2)> = 0.6603(5)(4) fm, where the first uncertainty is statistical as derived from the fit, while the second estimates the possible size of nonuniversal radiative corrections. In addition, we demonstrate that modern high-quality data for the decay. eta'-> pi(+) pi(-) will allow for an even improved determination of the transition strength omega -> pi(+) pi(-).
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| 4. |
- Hoferichter, M., et al.
(author)
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Dispersive analysis of the pion transition form factor
- 2014
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 74:11, s. 3180-
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Journal article (peer-reviewed)abstract
- We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the e(+) e(-) -> 3 pi cross section, generalizing previous studies on omega, phi -> 3 pi decays and gamma pi -> pi pi scattering, and verify our result by comparing to e(+) e(-) -> pi(0)gamma. data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below 1GeV, and extract the slope of the form factor at vanishing momentum transfer a(pi) = (30.7 +/- 0.6) x10(-3). We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
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| 5. |
- Yeung, Andy Wai Kan, et al.
(author)
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Resveratrol, a popular dietary supplement for human and animal health : Quantitative research literature analysis - a review
- 2019
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In: Animal Science Papers and Reports. - : POLSKA AKAD NAUK, INST GENETYKI I HODOWLI ZWIERZAT. - 0860-4037. ; 37:2, s. 103-118
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Research review (peer-reviewed)abstract
- Resveratrol is a stilbene-type bioactive molecule with a broad spectrum of reported biological effects. In this sense, the current work provides a comprehensive literature analysis on resveratrol, representing a highly-researched commercially available dietary ingredient. Bibliometric data were identified by means of the search string TOPIC=("resveratrol*") and analyzed with the VOSviewer software, which yielded 17,561 publications extracted from the Web of Science Core Collection electronic database. 'I'he ratio of original articles to reviews was 9.5:1. More than half of the overall manuscripts have been published since 2013. Major contributing countries were USA, China, Italy, South Korea, and Spain. Most of the publications appeared in journals specialized in biochemistry and molecular biology, pharmacology and pharmacy, food science technology, cell biology, or oncology. The phytochemicals or phytochemical classes that were frequently mentioned in the keywords of analyzed publications included, in descending order: resveratrol, trans-resveratrol, polyphenols, flavonoids, quercetin, stilbenes, curcumin, piceatannol, cis-resveratrol, and anthocyanins.
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