Measurement of the $e^+e^-\to\pi^+\pi^-$ cross section from threshold to   1.2 GeV with the CMD-3 detector

CMD-3 Collaboration: F. V. Ignatov (1; 2); R. R. Akhmetshin (1 and; 2); A. N. Amirkhanov (1; 2); A. V. Anisenkov (1; 2); V. M. Aulchenko (1; and 2); N. S. Bashtovoy (1); D. E. Berkaev (1; 2); A. E. Bondar (1; 2),; A. V. Bragin (1); S. I. Eidelman (1; 2); D. A. Epifanov (1; 2); L. B.; Epshteyn (1; 2; 3); A. L. Erofeev (1; 2); G. V. Fedotovich (1 and; 2); A. O. Gorkovenko (1; 3); F. J. Grancagnolo (5); A. A. Grebenuk (1 and; 2); S. S. Gribanov (1; 2); D. N. Grigoriev (1; 2; 3); V. L. Ivanov; (1; 2); S. V. Karpov (1); A. S. Kasaev (1); V. F. Kazanin (1; 2); B. I.; Khazin (1); A. N. Kirpotin (1); I. A. Koop (1; 2); A. A. Korobov (1 and; 2); A. N. Kozyrev (1; 3); E. A. Kozyrev (1; 2); P. P. Krokovny (1 and; 2); A. E. Kuzmenko (1); A. S. Kuzmin (1; 2); I. B. Logashenko (1; 2),; P. A. Lukin (1; 2); A. P. Lysenko (1); K. Yu. Mikhailov (1; 2); I. V.; Obraztsov (1; 2); V. S. Okhapkin (1); A. V. Otboev (1); E. A.; Perevedentsev (1; 2); Yu. N. Pestov (1); A. S. Popov (1; 2); G. P.; Razuvaev (1; 2); Yu. A. Rogovsky (1; 2); A. A. Ruban (1); N. M.; Ryskulov (1); A. E. Ryzhenenkov (1; 2); A. V. Semenov (1; 2); A. I.; Senchenko (1); P. Yu. Shatunov (1); Yu. M. Shatunov (1); V. E. Shebalin (1; and 2); D. N. Shemyakin (1; 2); B. A. Shwartz (1; 2); D. B. Shwartz (1; and 2); A. L. Sibidanov (4); E. P. Solodov (1; 2); A. A. Talyshev (1 and; 2); M. V. Timoshenko (1); V. M. Titov (1); S. S. Tolmachev (1; 2); A. I.; Vorobiov (1); I. M. Zemlyansky (1); D. S. Zhadan (1); Yu. M. Zharinov (1); A.; S. Zubakin (1); Yu. V. Yudin (1; 2) ((1) Budker Institute of Nuclear; Physics; Novosibirsk; (2) Novosibirsk State University; (3) Novosibirsk State; Technical University; (4) University of Victoria; (5) Instituto Nazionale di; Fisica Nucleare; Sezione di Lecce)

arXiv:2302.08834·hep-ex·June 6, 2024·29 cites

Measurement of the $e^+e^-\to\pi^+\pi^-$ cross section from threshold to 1.2 GeV with the CMD-3 detector

CMD-3 Collaboration: F. V. Ignatov (1, 2), R. R. Akhmetshin (1 and, 2), A. N. Amirkhanov (1, 2), A. V. Anisenkov (1, 2), V. M. Aulchenko (1, and 2), N. S. Bashtovoy (1), D. E. Berkaev (1, 2), A. E. Bondar (1, 2),, A. V. Bragin (1), S. I. Eidelman (1, 2), D. A. Epifanov (1, 2)

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TL;DR

This paper reports precise measurements of the $e^+e^- o ext{pi}^+ ext{pi}^-$ cross section from 0.32 to 1.2 GeV using the CMD-3 detector, providing new insights into the hadronic contribution to muon g-2.

Contribution

First high-resolution measurement of the $e^+e^- o ext{pi}^+ ext{pi}^-$ cross section around the $ ext{phi}$-resonance, with detailed asymmetry analysis and reduced systematic uncertainties.

Findings

01

Measured cross section with 0.7% uncertainty in the $ ho$-region.

02

First measurement of $ ext{pi}^+ ext{pi}^-$ production near $ ext{phi}$-resonance.

03

Observed deviation of charge asymmetry from scalar QED predictions.

Abstract

The cross section of the process $e^{+} e^{-} \to π^{+} π^{-}$ has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The measurement is based on a full dataset collected below 1 GeV during three data taking seasons, corresponding to an integrated luminosity of about 62 pb $^{- 1}$ . In the dominant $ρ$ -resonance region, a systematic uncertainty of 0.7% has been reached. At energies around $ϕ$ -resonance the $π^{+} π^{-}$ production cross section was measured for the first time with high beam energy resolution. The forward-backward charge asymmetry in the $π^{+} π^{-}$ production has also been measured. It shows a strong deviation from the theoretical prediction based on the conventional scalar quantum electrodynamics framework, and it is in good agreement with the generalized vector-meson-dominance and…

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Taxonomy

TopicsParticle physics theoretical and experimental studies · High-Energy Particle Collisions Research · Computational Physics and Python Applications