HEPData Search

Resonance production in the γγ reactionse+e−→e+e+e−π0π0 ande+e−π0η has been studied with the JADE detector at PETRA. The decay widths into γγ of thef2(1270),a0(980) anda2(1320) were measured to be$\Gamma _{\gamma \gamma } (f_2 (1270)) = 3.19 \pm 0.09_{ - 0.38}^{ + 0.22} $ Kev,Γλλ(a0(980))=0.28±0.04±0.10 KeV/BR(a0(980)→π0η) andΓλλ(a2(1320))=1.01±0.14±0.22KeV. For thef0(975) andf4(2050) upper limits of the widths were obtained,Γλλ(f0(975))<0.6 KeV, andΓλλ(f4(2050))<1.1 KeV, both at the 95% C.L. Assuming that the spin 0 background under thef2(1270) is small, thef2(1270) was found to be produced exclusively in a helicity 2 state. The helicity 0 contribution is <15% at the 95% C.L. The cross section forλλ→π0π0 in the mass range 2.0–3.5 GeV/c2 was measured for the first time. Since the cross section forλλ→π+π− is a factor ∼2 larger, ππ production in this range can be interpreted as taking place via isospin 0 production.

6 data tables

Table 1

Cross section for ABS(COS(THETA*)) < 0.3.

Table 2

Cross section under assumptions of spin 2, helicity 2 production.

Table 3

Cross section under assumption of spin 0 production.

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Experimental Evidence for the Nonabelian Nature of {QCD}

The AMY collaboration Park, I.H. ; Schnetzer, S. ; Green, J. ; et al.

Phys.Rev.Lett. 62 (1989) 1713, 1989.

Inspire Record 276619 DOI 10.17182/hepdata.20045

We present evidence for the non-Abelian nature of QCD from a study of multijet events produced in e+e− annihilations from √s =50 to 57 GeV in the AMY detector at the KEK storage ring TRISTAN. A comparison of the three-jet event fraction at TRISTAN to the fraction of the DESY storage ring PETRA shows that the QCD coupling strength αs decreases with increasing Q2. In addition, measurements of the angular distributions of four-jet events show evidence for the triple-gluon vertex.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Direct Photon Production in $e^+ e^-$ Annihilation

Fernandez, E. ; Ford, William T. ; Qi, N. ; et al.

Phys.Rev.Lett. 54 (1985) 95, 1985.

Inspire Record 204606 DOI 10.17182/hepdata.20304

Direct photon production in hadronic events from e+e− annihilation has been studied at s=29 GeV with use of the MAC detector at the PEP storage ring. A charge asymmetry A=(−12.3±3.5)% is observed in the final-state jets. The cross section and the charge asymmetry are in good agreement with the predictions of the fractionally charged quark-parton model. Both the charge asymmetry and total yield have been used to determine values of quark charges. Limits have been established for anomalous sources of direct photons.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Search for Singly Produced Supersymmetric Electrons in $e^+ e^-$ Interactions

Fernandez, E. ; Ford, William T. ; Read, Alexander L. ; et al.

Phys.Rev.Lett. 52 (1984) 22, 1984.

Inspire Record 192872 DOI 10.17182/hepdata.20447

A search for supersymmetric electron production via the reaction e+e−→e±γ̃ẽ∓ followed by the decay ẽ∓→e∓γ̃ has been performed with the MAC detector at the electron-positron storage ring PEP. No candidates were found in a sample corresponding to an integrated luminosity of 36.4 pb−1. For a massless γ̃ this corresponds to a lower limit on the ẽ mass of 22.4 GeV/c2 at the 95% confidence level.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

rivet Analysis
Production of $\pi^0 \pi^0$ and $\pi^0 \eta$ in Photon - Photon Collisions

Edwards, C. ; Partridge, Richard ; Peck, C. ; et al.

Phys.Lett.B 110 (1982) 82-86, 1982.

Inspire Record 168793 DOI 10.17182/hepdata.30959

We investigate the four-photon final state produced in γγ colissions. In the π 0 π 0 channel we observe f(1270) production with predominantly helicity 2 and measure a partial width Γ γγ 2.9 +0.6 −0.4 ± keV (independent of assumptions on the helicity). We observe A 2 (1310) production in the π 0 η channel and find a partial width Γ γγ = 0.77 ± 0.18 ± 0.27 KeV (assuming helicity 2). We give an upper limit for f ≈ ηη .

3 data tables

Table 1

Data read from graph. Systematic error on M is of order of 2% or less.

Table 2

Data read from graph.

Table 3

No description provided.

Date

Collaboration

Subject_areas

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Reactions

Observables Reset

CM Energies (GeV)

Authors Reset

Measurement of three jet distributions sensitive to the gluon spin in e+ e- annihilations at S**(1/2) = 91-GeV

rivet Analysis
Measurement of Resonance Productions in the Reactions $\gamma \gamma \to \pi^0 \pi^0$ and $\gamma \gamma \to \pi^0 \eta$

Experimental Evidence for the Nonabelian Nature of {QCD}

Direct Photon Production in $e^+ e^-$ Annihilation

Search for Singly Produced Supersymmetric Electrons in $e^+ e^-$ Interactions

rivet Analysis
Production of $\pi^0 \pi^0$ and $\pi^0 \eta$ in Photon - Photon Collisions

Date

Collaboration

Subject_areas

Phrases

Reactions

Observables Reset

CM Energies (GeV)

Authors Reset

Measurement of three jet distributions sensitive to the gluon spin in e+ e- annihilations at S**(1/2) = 91-GeV

rivet Analysis Measurement of Resonance Productions in the Reactions $\gamma \gamma \to \pi^0 \pi^0$ and $\gamma \gamma \to \pi^0 \eta$

Experimental Evidence for the Nonabelian Nature of {QCD}

Direct Photon Production in $e^+ e^-$ Annihilation

Search for Singly Produced Supersymmetric Electrons in $e^+ e^-$ Interactions

rivet Analysis Production of $\pi^0 \pi^0$ and $\pi^0 \eta$ in Photon - Photon Collisions

rivet Analysis
Measurement of Resonance Productions in the Reactions $\gamma \gamma \to \pi^0 \pi^0$ and $\gamma \gamma \to \pi^0 \eta$

rivet Analysis
Production of $\pi^0 \pi^0$ and $\pi^0 \eta$ in Photon - Photon Collisions