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Akhmetshin, R.R.; Anisenkov, A. V.; Aulchenko, V.; Banzarov, V.Sh.; Bashtovoy, N.S.; Berkaev, D. E.; Bondar, A.; Bragin, A.V.; Eidelman, S.; Epifanov, D.; Epshteyn, L.B.; Erofeev, A.L.; Fedotovich, G. V.; Gayazov, S.E.; Grebenuk, A.A.; Grigoriev, D.N.; Gromov, E.N.; Ignatov, F.V.; Karpov, S. V.; Казанин, В. Ф.; Khazin, B.I.; Koop, I. A.; Kovalenko, O. A.; Kozyrev, Aleksei; Kozyrev, E. A.; Krokovny, P.; Kuzmenko, A.E.; Kuzmin, A.; Logashenko, I.B.; Lukin, P.; Mikhailov, K.; Muchnoi, N. Yu.; Okhapkin, V.S.; Pestov, Y.; Perevedentsev, E. A.; Попов, А. С.; Razuvaev, G.P.; Rogovsky, Yu. A.; Romanov, Alexander; Рубан, А.А.; Ryskulov, N.M.; Ryzhenenkov, A.E.; Shebalin, V.; Shemyakin, D.N.; Shwartz, B.; Shwartz, D. B.; Sibidanov, A.; Shatunov, P. Yu.; Shatunov, Yu. M.; Solodov, E. P.; Титов, В.М.; Talyshev, A. A.; Воробйов, А.І.; Yudin, Yu.V.

doi:10.1016/j.physletb.2014.11.056

Cited by 26 publications

(22 citation statements)

References 16 publications

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“…17 We notice that the LO leading logs L correspond -not surprisingly as they arise from a power-like expansion as well -to the corrections found in [9, 10] if Λ is taken as the VMD scale. We adopt then a much more modest approach and retain the leading logs alone, which represents a good approximation.…”

Section: Jhep08(2016)108supporting

confidence: 75%

η and η ′ decays into lepton pairs

Masjuan

Sánchez-Puertas

2016

J. High Energ. Phys.

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In this work, we calculate the branching ratios for the η(η ) → decays, where = e, µ. These processes have tiny rates in the Standard Model due to spin flip, loop and electromagnetic suppressions, which could make them sensitive to New Physics effects. In order to provide a reliable input for the Standard Model, we exploit the general analytical properties of the amplitude. For that purpose, we invoke the machinery of Canterbury approximants, which provides a systematic description of the underlying hadronic physics in a data-driven fashion. Given the current experimental discrepancies, we discuss in detail the role of the resonant region and comment on the reliability of χPT calculations. Finally, we discuss the kind of new physics which we think would be relevant to account for them.

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Section: Jhep08(2016)108supporting

confidence: 75%

η and η ′ decays into lepton pairs

Masjuan

Sánchez-Puertas

2016

J. High Energ. Phys.

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“…This makes very interesting both, a new measurement of these decays with higher precision to discard a statistical fluctuation, and a first measurement of the doubly-virtual TFF, which would determine once for all the nature of the discrepancy. Moreover, given our obtained value for the η → e + e − result and present bounds [29,30], we would like to encourage our experimental colleagues in Novosibirsk to push further their measurement at SND and CMD-III to reach this limit, higher than naive expectations from the (wrong) unitary bound.…”

Section: Pos(cd15)064mentioning

confidence: 73%

“…This suggests that the real value should lie within a 1,1 ∈ {b 2 P , 2b 2 P } range 1 . η → e + e − (1.82 ÷ 1.86)(19) × 10 −10 ≤ 5.6 × 10 −9 [29,30] η → µ + µ − (1.36 ÷ 1.49)(33) × 10 −7 − Of course, experimental data or lattice QCD will have the last word on this. For the moment, we take this range for our calculations as the best estimate to be on the conservative side.…”

Section: Pos(cd15)064mentioning

confidence: 99%

Pseudoscalar decays into lepton pairs from rational approximants

Sánchez-Puertas

Gutenberg-Universität

Masjuan

2016

Proceedings of the 8th International Workshop on Chiral Dynamics — PoS(CD15)

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The pseudoscalar decays into lepton pairs P → are analyzed with the machinery of Canterbury approximants, an extension of Padé approximants to bivariate functions. This framework provides an ideal model-independent approach to implement all our knowledge of the pseudoscalar transition form factors driving these decays, can be used for data analysis, and allows to include experimental data and theoretical constraints in an easy way, and determine a systematic error. We find that previous theoretical estimates for these branching ratios have underestimated their theoretical uncertainties. From our updated results, the existing experimental discrepancies for π 0 → e + e − and η → µ + µ − channels cannot be explained unless the doubly-virtual transition form factors behavior -not yet measured-are out of theoretical expectations, which is an interesting result both for anomalous magnetic moments of leptons, and for physics beyond the standard model.

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“…[31] to measure the partial width of a strongly suppressed η → e + e − decay using the inverse process. CMD-3 reported an upper limit of Γ(η → e + e − ) < 0.0024 eV at 90% CL based on 2.69 pb −1 and one mode of η decay [32]. SND used 2.9 pb −1 and five modes of η decay to improve it to Cross section of the process e + e − → nn at SND [28] < 0.0020 eV.…”

Section: Experiments At Vepp-2000mentioning

confidence: 99%