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Measurement of the $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ cross section in the energy range 0.62-3.50 GeV at Belle II

The Belle-II collaboration Adachi, I. ; Aggarwal, L. ; Aihara, H. ; et al.

Phys.Rev.D 110 (2024) 112005, 2024.

Inspire Record 2775022 DOI 10.17182/hepdata.155340

We report a measurement of the $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ 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 $Υ (4 S)$ resonance with the Belle II detector at the SuperKEKB collider. Signal yields are extracted by fitting the two-photon mass distribution in $e^{+} e^{-} \to π^{+} π^{-} π^{0} γ$ events, which involve a $π^{0} \to γ γ$ 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 $ω$ and $ϕ$ resonances is dominated by the systematic uncertainty of 2.2%. The resulting cross sections in the 0.62-1.80 GeV energy range yield $a_{μ}^{3 π} = [48.91 \pm 0.23 (stat) \pm 1.07 (syst)] \times 10^{- 10}$ 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.

5 data tables

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

Energy bin range ( $\sqrt{s^{'}}$ ), number of events after unfolding ( $N_{unf}$ ), corrected efficiency ( $ε$ ), and cross section ( $σ_{3 π}$ ) for $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ in energy range 0.62--1.05~GeV. The two uncertainties in the cross section are the statistical and systematic contributions. The statistical uncertainties for the unfolding and cross section are square roots of the diagonal components of the unfolding covariance matrix. The image shows Figure 23 in the PRD paper, and the points with error bars indicate the cross section in the table.

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

Energy bin range ( $\sqrt{s^{'}}$ ), number of events after unfolding ( $N_{unf}$ ), corrected efficiency ( $ε$ ), and cross section ( $σ_{3 π}$ ) for $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ in energy range 1.05--3.50~GeV. The two uncertainties in the cross section are the statistical and systematic contributions. The statistical uncertainties for the unfolding and cross section are square roots of the diagonal components of the unfolding covariance matrix. The image shows Figure 23 in the PRD paper, and the points with error bars indicate the cross section in the table.

Cross section, statistical covariance

The statistic covariance matrix for the $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ cross section measurement at the Belle II. The 212 x 212 matrix of the energy ranges from 0.62 to 3.50 GeV. This covariance matrix, obtained by propagating the covariance matrix in the unfolding procedure, shows the total statistical uncertainties for the cross section results.

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Measurement of the angular dependence of the polarization of the recoil protons from the photoproduction of neutral pions on hydrogen at proton energies between 240 and 420 MeV

Althoff, K.H. ; Finken, D. ; Minatti, N. ; et al.

Phys.Lett.B 26 (1968) 677-678, 1968.

Inspire Record 1392747 DOI 10.17182/hepdata.29304

New measurements of the polarization of the recoil protons from the reaction γ + p → π o + p are reported for the region of the first resonance. These measurements are an extension of earlier experiments, done on the 500 MeV-electron-synchroton. More data have been taken at photon energies of 240, 300, 360 and 420 MeV.

1 data table

Table 1

No description provided.

Measurement of the analyzing power $A_{y}$ in neutron-proton radiative capture at $E_{n}$ = 68 MeV

Tuccillo, M. ; Fritschi, D. ; Götz, J. ; et al.

Nucl.Phys.A 580 (1994) 253-262, 1994.

Inspire Record 1389770 DOI 10.17182/hepdata.36513

The vector analyzing power Ay for the reaction Full-size image (<1 K) has been measured at five angles between 60° and 140° in the lab at an incident neutron energy of 67.7 MeV. The measurement is of a presision never before acheived (ΔAy ⩽ 0.01, statistical) for this observable. This precision makes possible a quantitative comparison with meson-exchange theories, thus enhancing our understanding of the role of non-nucleonic degrees of freedom.

1 data table

Table 1

No description provided.

Measurement of the spin correlation parameters $A_{x x}$ and $A_{y y}$ for proton-proton scattering at 47.5 MeV

Nisimura, K. ; Hasegawa, T. ; Saito, T. ; et al.

Phys.Lett.B 30 (1969) 612-613, 1969.

Inspire Record 1389659 DOI 10.17182/hepdata.28866

A measurement of the spin correlation parameters A xx (90° cm) and A yy (90° cm) of 47.5 MeV proton-proton scattering has been performed by means of polarized beam and a polarized target.

1 data table

Table 1

No description provided.

The transverse and longitudinal cross sections for electroproduction of pions near the Δ(1236)-isobar

Bartel, W. ; Dudelzak, B. ; Krehbiel, H. ; et al.

Phys.Lett.B 27 (1968) 660-662, 1968.

Inspire Record 1389642 DOI 10.17182/hepdata.29204

The reaction e + p → e ′+ N ∗ was studied for four momentum transfers up to 2.34 (GeV/ c ) 2 in the region of the 1236 MeV isobar. An analysis of the data in terms of the cross sections σ T and σ L for the absorption of transverse and longitudinal photons is given for invariant masses of the final pion nucleon system W =1.220 GeV and W =1.350 GeV.

3 data tables

Table 1

Total errors are presented.

Table 2

Total errors are presented.

Table 3

Total errors are presented.

Measurement of the angular distribution of the polarization of the recoil proton from the photoproduction of neutral pions on hydrogen at a photon energy of 360 MeV. II

Althoff, K.H. ; Kramp, K. ; Matthay, H. ; et al.

Z.Phys. 194 (1966) 144-155, 1966.

Inspire Record 1385255 DOI 10.17182/hepdata.16697

The angular distribution of the polarization of the recoil protons from the reactionγ+p→π 0+p has been measured at a photon energy of 360 MeV and at pion CM angles of 58°, 75°, 96° and 105°. The polarization of the protons has been determined by the left to right ratio in scattering on a helium gas target. The trajectory of each scattered proton has been measured by a system of spark chambers.

1 data table

Table 1

No description provided.

Measurement of the polarization of the recoil proton from the photoproduction of neutral pions on hydrogen in the region of the first resonance. I

Althoff, K.H. ; Kramp, K. ; Matthay, H. ; et al.

Z.Phys. 194 (1966) 135-143, 1966.

Inspire Record 1385256 DOI 10.17182/hepdata.16667

The polarization of the recoil proton from the reaction 7+p--->~pi0+p has been measured using liquid helium as polarization analyser. The photon energy has been varied between 250 and 360 MeV, the pion angle (CM) between 58 and 100.

1 data table

Table 1

No description provided.

Photoproduction of positive pions on hydrogen between 200 and 450 MeV

Althoff, K. ; Fischer, H. ; Paul, W. ;

Z.Phys. 175 (1963) 19-33, 1963.

Inspire Record 1385261 DOI 10.17182/hepdata.16824

Mit einem magnetischen Spektrometer wurde am Bonner 500 MeV-Elektronen-Synchrotron die Reaktionγ+p→π ++n für Photonenenergien zwischen 200 und 450 MeV untersucht. Es wurden Anregungskurven für die Lab

19 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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rivet Analysis
Cross sections for the reactions $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0}$ , $K_{S}^{0} K_{L}^{0} π^{+} π^{-}$ , $K_{S}^{0} K_{S}^{0} π^{+} π^{-}$ , and $K_{S}^{0} K_{S}^{0} K^{+} K^{-}$ from events with initial-state radiation

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.

Phys.Rev.D 89 (2014) 092002, 2014.

Inspire Record 1287920 DOI 10.17182/hepdata.64506

We study the processes $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0} γ$ , $K_{S}^{0} K_{L}^{0} π^{+} π^{-} γ$ , $K_{S}^{0} K_{S}^{0} π^{+} π^{-} γ$ , and $K_{S}^{0} K_{S}^{0} K^{+} K^{-} γ$ , where the photon is radiated from the initial state, providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb $^{- 1}$ of data collected with the BaBar detector at SLAC. We observe the $ϕ (1020)$ resonance in the $K_{S}^{0} K_{L}^{0}$ final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0}$ cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0} π^{+} π^{-}$ , $K_{S}^{0} K_{S}^{0} π^{+} π^{-}$ , and $K_{S}^{0} K_{S}^{0} K^{+} K^{-}$ cross sections, and study the intermediate resonance structures. We obtain the first observations of \jpsi decay to the $K_{S}^{0} K_{L}^{0} π^{+} π^{-}$ , $K_{S}^{0} K_{S}^{0} π^{+} π^{-}$ , and $K_{S}^{0} K_{S}^{0} K^{+} K^{-}$ final states.

22 data tables

Table 1

Cross section measurement for PHI(1020).

Table 2

Mass measurement for PHI(1020).

Table 3

Measurement of the PHI(1020) width.

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rivet Analysis
Study of e+e- --> p anti-p via initial-state radiation at BABAR

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.

Phys.Rev.D 87 (2013) 092005, 2013.

Inspire Record 1217421 DOI 10.17182/hepdata.62678

The process e+e- --> p anti-p gamma is studied using 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider, at an e+e- center-of-mass energy of 10.6 GeV. From the analysis of the p anti-p invariant mass spectrum, the energy dependence of the cross section for e+e- --> p anti-p is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, and the asymmetry in the proton angular distribution are measured for p anti-p masses below 3 GeV. We also measure the branching fractions for the decays J/psi --> p anti-p and psi(2S) --> p anti p.

1 data table

Table 1

Measurement of the cross section as a function of the invariant mass of the PBAR-P system and the effective form factor for the reaction E+ E- --> PBAR P. The contributions from J/PSI and PSI(25) decaying to PBAR-P have been subtracted. The form factor error is the combined statistical and systematic.

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Measurement of the $e^{+} e^{-} \to π^{+} π^{-} π^{0}$ cross section in the energy range 0.62-3.50 GeV at Belle II

Measurement of the angular dependence of the polarization of the recoil protons from the photoproduction of neutral pions on hydrogen at proton energies between 240 and 420 MeV

Measurement of the analyzing power $A_{y}$ in neutron-proton radiative capture at $E_{n}$ = 68 MeV

Measurement of the spin correlation parameters $A_{x x}$ and $A_{y y}$ for proton-proton scattering at 47.5 MeV

The transverse and longitudinal cross sections for electroproduction of pions near the Δ(1236)-isobar

Measurement of the angular distribution of the polarization of the recoil proton from the photoproduction of neutral pions on hydrogen at a photon energy of 360 MeV. II

Measurement of the polarization of the recoil proton from the photoproduction of neutral pions on hydrogen in the region of the first resonance. I

Photoproduction of positive pions on hydrogen between 200 and 450 MeV

rivet Analysis
Cross sections for the reactions $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0}$ , $K_{S}^{0} K_{L}^{0} π^{+} π^{-}$ , $K_{S}^{0} K_{S}^{0} π^{+} π^{-}$ , and $K_{S}^{0} K_{S}^{0} K^{+} K^{-}$ from events with initial-state radiation

rivet Analysis
Study of e+e- --> p anti-p via initial-state radiation at BABAR