Experiments at VEPP-2M with SND detector

The SND collaboration Achasov, M.N. ; Aulchenko, V.M. ; Baru, S.E. ; et al.
BINP-98-65, 1998.
Inspire Record 476386 DOI 10.17182/hepdata.50374

Short overview of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E = 400 - 1400 MeV and preliminary results of data analysis are presented.

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Summary of experiments with the neutral detector at the e+ e- storage ring VEPP-2M

Dolinsky, S.I. ; Druzhinin, V.P. ; Dubrovin, M.S. ; et al.
Phys.Rept. 202 (1991) 99-170, 1991.
Inspire Record 321108 DOI 10.17182/hepdata.19310

The complete results of the experiments carried out with the Neutral Detector at the e + e − storage ring VEPP-2M in the energy range 2 E =0.5–1.4 GeV are reviewed. The data sample corresponds to a total integrated luminosity of 19 pb −1 .

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ND results from Dolinsky et al., PL B174 (1986) 453.. Statistical errors only are shown. There is an additional systematic errorof 8%.

Averaged ND data.. Statistical errors only are shown. There is an additional systematic errorof 8%.

Cross section derived from ARGUS data, Albrecht et al., PL B185 (1987) 223.. Statistical errors only are shown. There is an additional systematic errorof 8%.

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The Process e+ e- to pi+ pi- pi0 in the energy range 2E(0) = 1.04-GeV - 1.38-GeV

Achasov, M.N. ; Aulchenko, V.M. ; Baru, S.E. ; et al.
Phys.Lett.B 462 (1999) 365-370, 1999.
Inspire Record 508003 DOI 10.17182/hepdata.28071

In the experiment with the SND detector at VEPP-2M e^+e^- collider the process $e^+e^-\to\pi^+\pi^-\pi^0$ was studied in the energy range 2E_0 from 1.04 to 1.38 GeV. A broad peak was observed with the visible mass $M_{vis}=1220\pm 20$ MeV and cross section in the maximum $\sigma_0\simeq 4$ nb. The peak can be interpreted as a $\omega$-like resonance $\omega (1200)$.

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The total cross section for E+ E- --> PI+ PI- PI0 after correction for efficiency and radiative effects.


Search for a Possible Exotic State C (1480) at the Vepp-2m Storage Ring

Aulchenko, V.M. ; Golubev, V.B. ; Dolinsky, S.I. ; et al.
JETP Lett. 45 (1987) 145-147, 1987.
Inspire Record 253283 DOI 10.17182/hepdata.2401
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The Reaction $e^+ e^- \to \Omega \pi^0$ in the Center-of-mass Energy Range From 1.0-{GeV} to 1.4-{GeV}

Dolinsky, S.I. ; Druzhinin, V.P. ; Dubrovin, M.S. ; et al.
Phys.Lett.B 174 (1986) 453-457, 1986.
Inspire Record 233797 DOI 10.17182/hepdata.69630

The reaction e + e - → ωπ 0 → π 0 π 0 γ has been studied with the Neutral Detector at the VEPP-2M collider. The cross section values differ from the predictions of the vector dominance model with one ϱ(770) meson, and are consistent with the contributions of ϱ(770) and ϱ(1600). ϱ(1250) has not been observed.

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Cross Sections for the Reactions e+e- --> K+ K- pi+pi-, K+ K- pi0pi0, and K+ K- K+ K- Measured Using Initial-State Radiation Events

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Prencipe, E. ; et al.
Phys.Rev.D 86 (2012) 012008, 2012.
Inspire Record 892684 DOI 10.17182/hepdata.62222

We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the \epem center-of-mass energy, so that the K+ K- pi+pi- data can be compared with direct measurements of the e+e- --> K+ K- pi+pi- reaction. No direct measurements exist for the e+e- --> K+ K-pi0pi0 or e+e- --> K+ K-K+ K- reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e+e- --> phi(1020)pipigamma reaction, and confirm the presence of the Y(2175) resonance in the phi(1020) f0(980) and K+K-f0(980) modes. In the charmonium region, we observe the J/psi in all three final states and in several intermediate states, as well as the psi(2S) in some modes, and measure the corresponding product of branching fraction and electron width.

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Cross section measurements for the reaction E+ E- --> PHI F0(600). Statistical errors only.


Study of $e^+e^- \to \omega\pi^0 \to \pi^0\pi^0\gamma$ in the energy range $1.05-2.00$ GeV with SND

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 88 (2013) 054013, 2013.
Inspire Record 1224801 DOI 10.17182/hepdata.62287

The cross section for the process e+e- --> omega pi0 --> pi0 pi0 gamma has been measured in the energy range 1.05--2.00 GeV. The experiment has been performed at the e+e- collider VEPP-2000 with the SND detector. The measured e+e- --> omega pi0 cross section above 1.4 GeV is the most accurate to date. Below 1.4 GeV our data are in good agreement with the previous SND and CMD-2 measurements. Data on the e+e- --> omega pi0 cross section are well described by the VMD model with two excited rho-like states. From the measured cross section we have extracted the gamma^* --> omega pi0 transition form factor. It has been found that the VDM model cannot describe simultaneously our data and data obtained from the omega --> pi0 mu+ mu- decay. We have also tested CVC hypothesis comparing our results on the e+e- --> omega pi0 cross section with data on the tau- --> omega pi- nu_{tau} decay.

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The c.m. energy(E) and measured Born cross section(SIG). For the cross section, the first error is statistical, the second is systematic.


Measurement of the $K_L$ nuclear interaction length in the NaI(Tl) calorimeter

Achasov, M.N. ; Beloborodov, K.I. ; Berdyugin, A.V. ; et al.
JINST 10 (2015) P09006, 2015.
Inspire Record 1392011 DOI 10.17182/hepdata.69471

In the study of the reaction $e^+e^-\to K_{S}K_{L}$ at the VEPP-2M $e^+e^-$ collider with the SND detector the nuclear interaction length of $K_{L}$ meson in NaI(Tl) has been measured. Its value is found to be 30--50 cm in the $K_{L}$ momentum range 0.11--0.48 GeV/$c$. The results are compared with the values used in the simulation programs GEANT4 and UNIMOD.

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The energy interval ($\sqrt{s}$), integrated luminosity ($IL$), number of selected events ($N$), number of background events ($N_{\rm bkg}$), number of events with five or more photons ($N_{5\gamma}$, $N_{5\gamma,{\rm bkg}}$), and the measured $K_L$ nuclear interaction length in NaI(Tl) ($\lambda_{\rm int}$).


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.

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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.


Investigation of the Reaction $e^+ e^- \to \eta \pi^+ \pi^-$ in the Energy Range Up to 1.4-{GeV}

Druzhinin, V.P. ; Dubrovin, M.S. ; Eidelman, S.I. ; et al.
Phys.Lett.B 174 (1986) 115-117, 1986.
Inspire Record 234174 DOI 10.17182/hepdata.30258

The reaction e + e − → ηπ + π − has been studied with the Neutral Detector in the CM energy range 1.05–1.40 GeV at VEPP-2M. At the maximum energy the cross section exceeds the prediction of the vector dominance with one ϱ(770). The following upper limits for the electron width times branching ratio into ηπ + π − have been obtained for a resonance with a mass of 1.28 GeV and width of 0.08 GeV observed with the Omega-spectrometer at CERN: Λ ee · B ηππ < 9 eV, and for a ϱ′(1250) with a mass of 1.26 GeV and width of 0.125 GeV: Λ ee · B ηππ < 14 eV at 90% confidence level.

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Axis error includes +- 10/10 contribution (RES-DEF(RES=ETA,DEF=530<M(2GAMMA)<570 MEV,BACK=CORRECTED)).