Abstract (data abstract)

We report a measurement of the $e^{+}e^{-} \to \pi^{+} \pi^{-} \pi^{0}$ cross section in the energy range from 0.62 to 3.50~GeV using an initial-state radiation technique. We use an $e^{+}e^{-}$ data sample corresponding to 191~fb$^{^-1}$ of integrated luminosity, collected at a center-of-mass energy at or near the $\Upsilon (4S)$ resonance with the \belletwo detector at the SuperKEKB collider. Signal yields are extracted by fitting the two-photon mass distribution in $e^{+}e^{-} \to \pi^{+} \pi^{-} \pi^{0} \gamma$ events, which involve a $\pi^{0} \to \gamma \gamma$ decay and an energetic photon radiated from the initial state. Signal efficiency corrections with an accuracy of 1.6\% are obtained from several control data samples.The uncertainty on the cross section at the $\omega$ and $\phi$ resonances is dominated by the systematic uncertainty of 2.2\%. The resulting cross sections in the 0.62--1.80~GeV energy range yield $a^{3\pi}_{\mu} = [48.91 \pm 0.23~(\mathrm{stat}) \pm 1.07~(\mathrm{syst})] \times 10^{-10}$ for the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. This result differs by $2.5$ standard deviations from the most precise current determination.

Table III: Cross section in energy range 0.62-1.05 GeV

Table III in PRD

10.17182/hepdata.155340.v1/t1

Energy bin range ($\sqrt{s'}$), number of events after unfolding ($N_{\mathrm{unf}}$), corrected efficiency ($\varepsilon$), and cross section ($\sigma_{3\pi}$) for $e^{+}e^{-} \to...
Table IV: Cross section in energy range 1.05-3.5 GeV

Table IV in PRD

10.17182/hepdata.155340.v1/t2

Energy bin range ($\sqrt{s'}$), number of events after unfolding ($N_{\mathrm{unf}}$), corrected efficiency ($\varepsilon$), and cross section ($\sigma_{3\pi}$) for $e^{+}e^{-} \to...
Cross section, statistical covariance

HEPData-only

10.17182/hepdata.155340.v1/t3

The statistic covariance matrix for the $e^+e^- \to \pi^+ \pi^- \pi^0$ cross section measurement at the Belle II. The 212...
Cross section, systematic covariance

HEPData-only

10.17182/hepdata.155340.v1/t4

The systematic covariance matrix for the $e^+e^- \to \pi^+ \pi^- \pi^0$ cross section measurement at the Belle II. The 212...
Cross section, inverse covariance covariance

HEPData-only

10.17182/hepdata.155340.v1/t5

This table provides the ``inverse'' of the total (stat.+ sys.) covariance matrix. This matrix can be used for a chi-square...

Table III: Cross section in energy range 0.62-1.05 GeV

Table IV: Cross section in energy range 1.05-3.5 GeV

Cross section, statistical covariance

Cross section, systematic covariance

Cross section, inverse covariance covariance

JSON

YAML

YODA

YODA1

ROOT

CSV

Visualize

Ask a Question