Pierre, F.
E+ E- Scattering
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Observation of Planar Three Jet Events in e+ e- Annihilation and Evidence for Gluon Bremsstrahlung

The JADE collaboration Bartel, W. ; Canzler, T. ; Cords, D. ; et al.
Phys.Lett.B 91 (1980) 142-147, 1980.
Inspire Record 143985 DOI 10.17182/hepdata.6339

Topological distributions of charged and neutral hadrons from the reaction e + e − → multihadrons are studied at √ s of about 30 GeV. An excess of planar events is observed at a rate which cannot be explained by statistical fluctuations in the standard two-jet process. The planar events, mostly consisting of a slim jet on one side and a broader jet on the other, are shown actually to possess three-jet structure by demonstrating that the broader jet itself consists of two collinear jets in its own rest system. Detailed agreement between data and predictions is obtained if the process e + e − →q q ̄ g is taken into account. This strongly suggests gluon bremsstrahlung as the origin of the planar three-jet events. By comparison of the data with the qq̄g-model we obtain a value for the strong coupling constant of α S ( q 2 = 0.17 ± 0.04.

2 data tables
Table 1

THRUST AND PLANARITY DISTRIBUTIONS. FINAL (BETTER) THRUST DISTRIBUTIONS WITH DETECTOR CORRECTIONS TO BE PUBLISHED LATER.

Table 2

No description provided.


Tests of Quantum Chromodynamics and a Direct Measurement of the Strong Coupling Constant $\alpha_S$ at $\sqrt{s}=30$-{GeV}

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Lett.B 89 (1979) 139-144, 1979.
Inspire Record 143680 DOI 10.17182/hepdata.6483

We report the measurement of the reaction e + + e − → hadronic jets at a center-of-mass energy √ s =30 GeV using the MARK-J detector at PETRA. By measuring the energy and angular distribution of both neutrals and charged particles we were able to isolate unambiguously the three-jet events in a kinematic region where the backgrounds from q q and phase space contributions and other processes are small. Various comparisons of the data with quantum chromodynamics were made. The relative yield of three-jet events and the shape distribution of the events enable us to determine α s = 0.23 ± 0.02 (statistical error) with a systematic error of ± 0.04.

2 data tables
Table 1

OBLATENESS AND THRUST DISTRIBUTIONS FOR NARROW AND BROAD JETS AT 30 GEV. THESE DATA ARE SOMEWHAT ANALYSIS AND DETECTOR DEPENDENT.

Table 2

No description provided.


rivet Analysis
Total Cross-Section for Hadron Production by e+ e- Annihilation at PETRA Energies

The JADE collaboration Bartel, W. ; Canzler, T. ; Cords, D. ; et al.
Phys.Lett.B 88 (1979) 171-176, 1979.
Inspire Record 142874 DOI 10.17182/hepdata.27277

The cross section for the process e + e − → multihadrons has been measured at the highest PETRA energies. We measure R (the total cross section in units of the point-like e + e - → μ + μ - cross section) to be 2.9 ± 0.7, 4.0 ± 0.5, 4.6 ± 0.4 and 4.2 ± 0.6 at s of 22, 27.7, 30 and 31.6 GeV, respectively. The observed average multiplicity, together with existing low energy data, indicate a rapid increase in multiplicity with increasing energy.

2 data tables
Table 1

STATISTICAL ERRORS ONLY. RADIATIVE CORRECTIONS APPLIED AND TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED. AVERAGE VALUE OF R FOR ALL THESE DATA IS 4.14 +- 0.26.

Table 2

AVERAGE CHARGE MULTIPLICITY. ADDITIONAL, SYSTEMATIC ERROR IS ABOUT 1.5.


Hadron Production by $e^+ e^-$ Annihilation at Center-of-mass Energies Between 2.6 GeV and 7.8 GeV

Siegrist, James Leon ; Schwitters, Roy F. ;
SLAC-R-0225, 1979.
Inspire Record 143687 DOI 10.17182/hepdata.18825

Results are presented on multihadron production by e+e- annihilation from the Mark I and Mark II detectors at SPEAR. Other-than the narrow resonances psi(3095) and psi'(3634), the total hadronic cross section varies between 36.5 and 6.4 nb over the center-of-mass energy range 2.6 to 7.8 GeV with complicated structure near 4.1 GeV not completely resolved by these measurements. Evidence for scaling of inclusive momentum distributions of hadrons is presented.

3 data tables
Table 1

No description provided.

Table 2

MORE DETAILED TABULATION OF R IN THE TRANSITION REGION.

Table 3

CHARGED SINGLE PARTICLE INCLUSIVE DISTRIBUTIONS FROM THIS EXPERIMENT ARE GIVEN IN THE RECORD OF G. G. HANSON, TBILISI CONFERENCE 1976, SLAC-PUB-1814.


rivet Analysis
Search for a 'Top' Threshold in Hadronic $e^+ e^-$ Annihilation at Energies Between 22-{GeV} and 31.6-{GeV}

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Grigull, R. ; et al.
Phys.Lett.B 86 (1979) 413-417, 1979.
Inspire Record 142517 DOI 10.17182/hepdata.27295

Results on e + e − annihilation into hadrons at c.m. energies between 22 and 31.6 GeV are presented. The data were accumulated with the PLUTO detector at PETRA. The events are dominantly of the two-jet type. The value of the relative hadronic cross section R =3.88 ± 0.22 along with the details of the sphericity and thrust distribution rule out an open (tt̄) channel (Q t = 2 3 ) below 30 GeV. The inclusive muon results support the above conclusion.

1 data table
Table 1

CROSS SECTIONS CORRECTED FOR BEAM-GAS SCATTERING BACKGROUND, INITIAL STATE RADIATION, TAU HEAVY LEPTON CONTRIBUTION AND TWO-PHOTON EVENTS.


TASSO RESULTS ON e+ e- ANNIHILATION BETWEEN 13-GeV AND 31.6-GeV AND EVIDENCE FOR THREE JET EVENTS

The TASSO collaboration Wolf, G. ; Brandelik, R. ; Braunschweig, W. ; et al.
eConf C790823 (1979) 34, 1979.
Inspire Record 142614 DOI 10.17182/hepdata.45227

None

2 data tables
Table 1

CORRECTIONS HAVE BEEN APPLIED FOR CONTRIBUTIONS FROM BEAM-GAS SCATTERING, TWO PHOTON SCATTERING, TAU HEAVY LEPTON PAIR PRODUCTION, AND FOR RADIATIVE EFFECTS. THE 13 AND 17 GEV MEASUREMENTS WERE PREVIOUSLY REPORTED IN R. BRANDELIK ET AL., PL 83B, 261 (1979).

Table 2

PRELIMINARY INCLUSIVE CHARGED PARTICLE DISTRIBUTIONS.


Evidence for Planar Events in e+ e- Annihilation at High-Energies

The TASSO collaboration Brandelik, R. ; Braunschweig, W. ; Gather, K. ; et al.
Phys.Lett.B 86 (1979) 243-249, 1979.
Inspire Record 142123 DOI 10.17182/hepdata.27312

Hadron jets produced in e + e − annihilation between 13 GeV and 31.6 GeV in c.m. at PETRA are analyzed. The transverse momentum of the jets is found to increase strongly with c.m. energy. The broadening of the jets is not uniform in azimuthal angle around the quark direction but tends to yield planar events with large and growing transverse momenta in the plane and smaller transverse momenta normal to the plane. The simple q q collinear jet picture is ruled out. The observation of planar events shows that there are three basic particles in the final state. Indeed, several events with three well-separated jets of hadrons are observed at the highest energies. This occurs naturally when the outgoing quark radiates a hard noncollinear gluon, i.e., e + e − → q q g with the quarks and the gluons fragmenting into hadrons with limited transverse momenta.

1 data table
Table 1

NORMALIZED TRANSVERSE MOMENTUM DISTRIBUTION WITH RESPECT TO THE SPHERICITY AXIS AT 13, 17, AND 27.4 TO 31.6 GEV.


Discovery of Three Jet Events and a Test of Quantum Chromodynamics at PETRA Energies

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 43 (1979) 830, 1979.
Inspire Record 142085 DOI 10.17182/hepdata.20742

We report the analysis of the spatial energy distribution of data for e+e−→hadrons obtained with the MARK-J detector at PETRA. We define the quantity "oblateness" to describe the flat shape of the energy configuration and the three-jet structure which is unambiguously observed for the first time. Our data can be explained by quantum chromodynamic predictions for the production of quark-antiquark pairs accompanied by hard noncollinear gluons.

1 data table
Table 1

AVERAGE OBLATENESS AS A FUNCTION OF SQRT(S) AND OF THRUST AND OBLATENESS DISTRIBUTION (1/N)*DN/DOBLATENESS AT 17 AND 27.4 TO 31.6 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.


A Test of Universality of Charged Leptons

Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Rev.Lett. 43 (1979) 1915, 1979.
Inspire Record 142012 DOI 10.17182/hepdata.20759

Measurements of the reactions e++e−→e++e−, μ++μ−, and τ++τ− at PETRA energies (s12=13,17,27.4,30 and 31.6 GeV) are reported. The results show that these reactions agree well with the predictions of quantum electrodynamics thus determining that all the known charged leptons are pointlike particles to a distance < × 10−16 cm.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


The hadronic final state in $e^{+}e^{-}$ annihilation at c.m. energies of 13, 17 and 27.4 GeV

The TASSO collaboration Cashmore, R.J. ; Brandelik, R. ; Braunschweig, W. ; et al.
1 (1979) 330-337, 1979.
Inspire Record 142275 DOI 10.17182/hepdata.45234

Results on the hadronic final state in e/sup +/e/sup -/ annihilation at 13, 17 and 27.4 GeV are presented. There is no compelling evidence for the existence of the t quark in these data, which are in general agreement with a simple quark parton model. Some tentative indications of QCD effects are observed in the p/sub T//sup 2/ distributions.

2 data tables
Table 1

TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED.

Table 2

INCLUSIVE HADRON SPECTRUM. THESE DATA AT 13, 17 AND 27.4 GEV ON S*D(SIG)/DX ARE INCLUDED IN THE RECORD OF R. BRANDELIK ET AL., PL 89B, 418 (1980).