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EXPERIMENTAL SEARCH FOR NARROW RESONANCES IN THE REACTION PI- P ---> GAMMA GAMMA N AT 13-GEV/C

Chiang, I.H. ; Johnson, R.A. ; Kwan, B.P. ; et al.

Phys.Lett.B 140 (1984) 145-148, 1984.

Inspire Record 206508 DOI 10.17182/hepdata.30553

Using a double arm electromagnetic calorimeter we have searched for narrow states produced in the exclusive reaction π − p→γγn at 13 GeV/c. No enhancements were observed in the mass range 2.0–4.0 GeV/c 2 . For example, the 90% confidence limit on η c production is σ ( π − p→ η c n)× B ( η c → γγ ) < 44 pb.

1 data table

Table 1

UPPER LIMIT (90 PCT CL) FOR SIG*BR(ETA/C --> 2 GAMMA).

SEARCH FOR EXCLUSIVE J / psi PRODUCTION

Chiang, I.H. ; Johnson, R.A. ; Kwan, B.P. ; et al.

Phys.Rev.D 34 (1986) 1619, 1986.

Inspire Record 228262 DOI 10.17182/hepdata.23503

We have searched for exclusive hadronic J/ψ production by looking for narrow resonances in the e+e− mass spectrum of the reaction π−p→e+e−n. No events were observed in the region around 3.1 GeV/c2. The cross section for the reaction π−p→J/ψ n at 13 GeV/c is no more than 103 pb at the 90% confidence level.

1 data table

Table 1

Corrected cross section based on 7.4 pct branching ratio.

The Spin Correlation Parameter and Analyzing Power in $n p$ Elastic Scattering at Intermediate-energies

Abegg, R. ; Ahmad, M. ; Bandyopadhyay, D. ; et al.

Phys.Rev.C 40 (1989) 2684-2696, 1989.

Inspire Record 281880 DOI 10.17182/hepdata.26220

In order to improve existing I=0 phase shift solutions, the spin correlation parameter ANN and the analyzing powers A0N and AN0 have been measured in n-p elastic scattering over an angular range of 50°–150° (c.m.) at three neutron energies (220, 325, and 425 MeV) to an absolute accuracy of ±0.03. The data have a profound effect on various phase parameters, particularly the P11, D23, and ε1 phase parameters which in some cases change by almost a degree. With the exception of the highest energy, the data support the predictions of the latest version of the Bonn potential. Also, the analyzing power data (A0N and AN0) measured at 477 MeV in a different experiment over a limited angular range [60°–80° (c.m.)] are reported here.

10 data tables

Table 1

The beam analysing power at incident kinetic energy 220 MeV. Additional systematic uncertainty of +- 0.015 and a scalar error of 3.5 PCT.

Table 2

The beam analysing power at incident kinetic energy 325 MeV. Additional systematic uncertainty of +- 0.018 and a scalar error of 3.1 PCT.

Table 3

The beam analysing power at incident kinetic energy 425 MeV. Additional systematic uncertainty of +- 0.022 and a scalar error of 3.3 PCT.

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Measurement of $n p \to d \pi^0$ Cross-sections Very Near Threshold

Hutcheon, D.A. ; Korkmaz, Elie J. ; Moss, G.A. ; et al.

Phys.Rev.Lett. 64 (1990) 176, 1990.

Inspire Record 281869 DOI 10.17182/hepdata.19959

We have measured np→dπ0 cross sections at eleven beam energies within 16 MeV of threshold. Total cross sections are only 0.67±0.10 of the value which has been generally accepted for s-wave pion production strength near threshold. The differential cross sections are anisotropic at only 1 MeV (c.m.) above threshold. Our results are compared to π+d→pp data and to predictions of two models.

1 data table

Table 1

Error quoted contains 2 PCT statistical uncertainty in acceptance measurement.

A Determination of the Properties of the Neutral Intermediate Vector Boson Z0

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 231 (1989) 509, 1989.

Inspire Record 282041 DOI 10.17182/hepdata.29768

We report the results of first physics runs of the L3 detector at LEP. Based on 2538 hadron events, we determined the mass m z 0 and the width Γ z 0 of the intermediate vector boson Z 0 to be m z 0 =91.132±0.057 GeV (not including the 46 MeV LEP machine energy uncertainty) and Γ z 0 =2.588±0.137 GeV. We also determined Γ invisible =0.567±0.080 GeV, corresponding to 3.42±0.48 number of neutrino flavors. We also measured the muon pair cross section and determined the branching ratio Γ μμ = Γ h =0.056±0.006. The partial width of Z 0 →e + e − is Γ ee =88±9±7 MeV.

1 data table

Table 1

No description provided.

FORWARD - BACKWARD CHARGE ASYMMETRY IN e+ e- ---> HADRON JETS

The AMY collaboration Stuart, D. ; Breedon, R.E. ; Kim, G.N. ; et al.

Phys.Rev.Lett. 64 (1990) 983, 1990.

Inspire Record 283082 DOI 10.17182/hepdata.19965

The forward-backward asymmetry of quarks produced in e+e− annihilations, summed over all flavors, is measured at √s between 50 and 60.8 GeV. Methods of determining the charge direction of jet pairs are discussed. The asymmetry is found to agree with the five-flavor standard model.

1 data table

Table 1

Forward backward asymmetry summed over all flavours of quarks.

Measurement of $g$(a) and $g(V$), the Neutral Current Coupling Constants to Leptons

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 236 (1990) 109-115, 1990.

Inspire Record 283470 DOI 10.17182/hepdata.29715

We have measured both the rates and the forward-backward asymmetry of ℓ + ℓ − from Z 0 →ℓ + ℓ − (where ℓ= μ , τ ) with the L3 detector. We obtained Γ ℓℓ =88±4±3 MeV and the vector neutral current coupling constant, g v =0.00±0.07 and the axial vector neutral current coupling constant, g A =−0.515±0.015.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

rivet Analysis
MULTI - HADRON EVENT PROPERTIES IN e+ e- ANNIHILATION AT s**(1/2) = 52-GeV to 57-GeV

The AMY collaboration Li, Y.K. ; Li, J. ; Cheng, C.P. ; et al.

Phys.Rev.D 41 (1990) 2675, 1990.

Inspire Record 283337 DOI 10.17182/hepdata.38416

We present the general properties of multihadron final states produced by e+e− annihilation at center-of-mass energies from 52 to 57 GeV in the AMY detector at the KEK collider TRISTAN. Global shape, inclusive charged-particle, and particle-flow distributions are presented. Our measurements are compared with QCD+fragmentation models that use either leading-logarithmic parton-shower evolution or QCD matrix elements at the parton level, and either string or cluster fragmentation for hadronization.

22 data tables

Table 1

Rapidity distribution with respect to the Thrust axis.

Table 2

Charged particle X distribution.

Table 3

Charged particle PL distribution.

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Measurement of $\Z^0$ Decays to Hadrons and a Precise Determination of the Number of Neutrino Species

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 237 (1990) 136-146, 1990.

Inspire Record 286423 DOI 10.17182/hepdata.29736

We have made a precise measurement of the cross section for e + e − →Z 0 →hadrons with the L3 detector at LEP, covering the s range from 88.28 to 95.04 GeV. From a fit to the Z 0 mass, total width, and the hadronic cross section to be M Z 0 =91.160 ± 0.024 (experiment) ±0.030(LEP) GeV, Γ Z 0 =2.539±0.054 GeV, and σ h ( M Z 0 )=29.5±0.7 nb. We also used the fit to the Z 0 peak cross section and the width todetermine Γ invisible =0.548±0.029 GeV, which corresponds to 3.29±0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4σ confidence level.

2 data tables

Table 1

No description provided.

Table 2

Total hadronic cross section.