HEPData Search

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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.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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rivet Analysis
Study of dynamics of Phi --> pi+ pi- pi0 decay with CMD-2 detector.

Akhmetshin, R.R ; Aksenov, G.A ; Anashkin, E.V ; et al.

Phys.Lett.B 434 (1998) 426-436, 1998.

Inspire Record 480170 DOI 10.17182/hepdata.28172

A study of the φ → π + π − π 0 decay mode has been performed using a data sample of about 2.0 million φ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. The following parameters of the φ -meson have been measured: Br ( φ → π + π − π 0 )=0.145±0.009±0.003 and δ φ − ω =162±17°. The analysis of the Dalitz plot showed the dominance of the φ → ρπ intermediate mechanism, the limits for the ratio of the direct amplitude of φ →3 π to that of φ → ρπ are −0.16< a 1 <0.11 at 90% C.L. The upper limits for the probabilities of the decay modes φ → π + π − η and direct φ → ργγ have been found for the first time: Br ( φ → π + π − η )<3×10 −4 and Br ( φ → ργγ )<5×10 −4 at 90% C.L.

1 data table

Table 1

No description provided.

rivet Analysis
a_1(1260) dominance in the process e+e- \to 4\pi at energies 1.05--1.38 GeV

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Arpagaus, M. ; et al.

Phys.Lett.B 466 (1999) 392-402, 1999.

Inspire Record 483994 DOI 10.17182/hepdata.50145

First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to \pi^+\pi^- 2\pi^0 and e+e- \to 2\pi^+ 2\pi^- has been measured. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Upper limits for the contributions of other alternative mechanisms are also placed.

3 data tables

Table 1

Energy dependence of the cross section for the 2PI+ 2PI- final state. Statistical errors only.

Table 2

Energy dependence of the cross section for the PI+ PI- 2PI0 final state. Statistical errors only.

Table 3

Energy dependence of the cross section for the OMEGA PI0 final state. Statistical errors only.

Search for rare Phi decays in pi+ pi_ gamma final state

The CMD-2 collaboration Akhmetshin, R.R. ; Aksenov, G.A. ; Anashkin, E.V. ; et al.

Phys.Lett.B 415 (1997) 452-462, 1997.

Inspire Record 451091 DOI 10.17182/hepdata.41643

A search for phi radiative decays has been performed using a data sample of about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive interference with the Bremsstrahlung process respectively, B(phi -> gamma -> pi+ pi- gamma) < 3x10-5 for E of gamma > 20 MeV, B(phi -> rho gamma) < 7x10-4. From the selected e+ e- -> mu+ mu- gamma events B(phi -> mu+ mu- gamma) = (2.3+-1.0)x10-5 has been obtained for E of gamma> 20 MeV. The upper limit on the P,CP-violating decay eta -> pi+ pi- has also been placed: B(eta -> pi+ pi-) < 9x10-4 . All upper limits are at 90 % C.L.

1 data table

Table 1

Only statistical errors are shown in the table.

rivet Analysis
Measurement of phi meson parameters with CMD-2 detector at VEPP-2M collider

Akhmetshin, R.R. ; Aksenov, G.A. ; Anashkin, E.V. ; et al.

Phys.Lett.B 364 (1995) 199-206, 1995.

Inspire Record 406880 DOI 10.17182/hepdata.28437

Results of the measurement of the φ meson parameters with the general purpose detector CMD-2 at the upgraded e + e − collider VEPP-2M at Novosibirsk are presented. This is the first measurement of the four major φ decay modes in a single e + e − experiment. The results based on about 55,600 identified hadronic events are consistent with previous measurements, and have precision comparable to the current world average.

1 data table

Table 1

No description provided.

Measurement of the spin rotation parameter A+ in the elastic scattering of positive pions on a longitudinally polarized proton target in the second resonance region

The ITEP-PNPI collaboration Alekseev, I.G. ; Bobchenko, B.M. ; Budkovsky, P.E. ; et al.

Phys.Lett.B 351 (1995) 585-590, 1995.

Inspire Record 403317 DOI 10.17182/hepdata.28540

The ITEP-PNPI collaboration presents the first results of the spin rotation parameter A + measurements in the second resonance region. The experiment was performed at the ITEP accelerator at a positive pion beam momentum 1.43 GeV/c for scattering angles θ cm = 127° and 133°. The setup was based on a polarized proton target and a carbon-plate polarimeter. The obtained data is compared with the predictions of the existing partial-wave analyses.

1 data table

Table 1

No description provided.

Asymmetry in $\pi^- P$ (Polarized) Elastic Scattering in Momentum Range 1.4-{GeV}/c - 2.1-{GeV}/c

Alekseev, I.G. ; Budkovsky, P.E. ; Kanavets, V.P. ; et al.

Nucl.Phys.B 348 (1991) 257-275, 1991.

Inspire Record 285067 DOI 10.17182/hepdata.33071

Results of systematic measurements of the asymmetry parameter in the elastic scattering of pions on polarized protons at 1.4–2.1 GeV/ c in the backward hemisphere are presented together with a test of the isospin invariance of the data set available on pion-proton scattering in the investigated momentum range. The transversity isodoublet amplitudes at 1.98 and 2.07 GeV/ c are reconstructed. The obtained data, the isospin analysis and amplitude reconstruction results are compared with the current phase-shift analysis predictions.

1 data table

Table 1

No description provided.