Measurement of the $e^+e^- \to \eta\pi^+\pi^-$ cross section in the center-of-mass energy range 1.22--2.00 GeV with the SND detector at the VEPP-2000 collider

The SND collaboration Aulchenko, V.M. ; Achasov, M.N. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 91 (2015) 052013, 2015.
Inspire Record 1332929 DOI 10.17182/hepdata.73176

In the experiment with the SND detector at the VEPP-2000 $e^+e^-$ collider the cross section for the process $e^+e^-\to\eta\pi^+\pi^-$ has been measured in the center-of-mass energy range from 1.22 to 2.00 GeV. Obtained results are in agreement with previous measurements and have better accuracy. The energy dependence of the $e^+e^-\to\eta\pi^+\pi^-$ cross section has been fitted with the vector-meson dominance model. From this fit the product of the branching fractions $B(\rho(1450)\to\eta\pi^+\pi^-)B(\rho(1450)\to e^+e^-)$ has been extracted and compared with the same products for $\rho(1450)\to\omega\pi^0$ and $\rho(1450)\to\pi^+\pi^-$ decays. The obtained cross section data have been also used to test the conservation of vector current hypothesis.

1 data table

The c.m. energy ($\sqrt{s}$), integrated luminosity ($L$), detection efficiency ($\varepsilon$), number of selected signal events ($N$), radiative-correction factor ($1 + \delta$), measured $e^+e^- \to \eta \pi^+\pi^-$ Born cross section ($\sigma_B$). For the number of events and cross section the statistical error is quoted. The systematic uncertainty on the cross section is 8.3% at $\sqrt{s}<1.45$ GeV, 5.0% at $1.45<\sqrt{s}<1.60$ GeV, and 7.8% at $\sqrt{s}>1.60$ GeV.


Final Results on $\mu e$ Pair Production in Neutrino Interactions With Chamber Skat Filled With Freon

Ammosov, V.V. ; Ermolaev, V.I. ; Ivanilov, A.A. ; et al.
Z.Phys.C 40 (1988) 493, 1988.
Inspire Record 263220 DOI 10.17182/hepdata.15559

We present the final results from the search for μe pairs produced in neutrino interactions using the freon filled bubble chamber SKAT. The rate of μ−e+ pairs to charged current events above the charm threshold is\(R_{\mu ^ -e^ +}= (4.8 \pm 1.1)10^{ - 3} \). Assuming charm particle production to be the origin of the positron we calculate\(R_{\Lambda _c^ +}= (6.2 \pm 3.1)10^{ - 2} \) andRD=(2.8±0.9)10−2. We observe no considerable μ−e− pair production above the background. In the regionEv>3 GeV,pμ,e>1.0 GeV/c andpμ>pe we find with a 90% confidence level the limit\(R_{\mu ^ -e^ -}< 1.7 10^{ - 4} \).

3 data tables

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Yield of $\mu^- e^+$ Pairs in Muon-neutrino $N$ Interaction in Skat Bubble Chamber

Korotkov, V.A. ; Kuznetsov, E.P. ; Makeev, V.V. ; et al.
JETP Lett. 31 (1980) 728, 1980.
Inspire Record 153555 DOI 10.17182/hepdata.11117

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2 data tables

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