Sixel, P.
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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.


Direct Production of High $p_T$ Single Photons at the {CERN} Intersecting Storage Rings

The Athens-Athens-Brookhaven-CERN collaboration Diakonou, M. ; Kourkoumelis, C. ; Resvanis, L.K. ; et al.
Phys.Lett.B 87 (1979) 292-296, 1979.
Inspire Record 143254 DOI 10.17182/hepdata.27293

Single photon production in pp collisions at 30 < √ s < 62 GeV has been measured with liquid-argon-lead calorimeters at the CERN ISR. This process remains approximately constant with increasing √ s . For fixed √ s , the single photon to π 0 ratio increases strongly with increase in p T . The γ π 0 ratio is about 0.2 for p T above 4.5 GeV/c.

1 data table
Table 1

No description provided.


Measurement of High-energy Direct Photons in $\psi$ Decays

Abrams, G.S. ; Alam, M.S. ; Blocker, C.A. ; et al.
Phys.Rev.Lett. 44 (1980) 114, 1980.
Inspire Record 142835 DOI 10.17182/hepdata.20729

The inclusive γ and π0 momentum distributions at the ψ have been measured. Using these data and estimates of η production, it is found that (4.1 ± 0.8)% of ψ decays contain a direct photon with energy greater than 60% of the beam energy. The expected momentum distribution for direct photons calculated to lowest order in quantum chromodynamics is qualitatively different from that observed in the data.

1 data table
Table 1

INCLUSIVE PHOTON AND PI0 MOMENTUM DISTRIBUTION.


Evidence for Direct $\gamma$ Production at Large $x$ in $\psi$ (3100) Decay

Ronan, M.T. ; Trippe, T.G. ; Barbaro-Galtieri, A. ; et al.
Phys.Rev.Lett. 44 (1980) 367, 1980.
Inspire Record 142946 DOI 10.17182/hepdata.20700

The inclusive γ and π0 momentum spectra from ψ(3100) decay have been measured in e+e− annihilation at SPEAR. When the γ spectrum is compared with that expected from π0 decay, an excess of high-momentum γ's is observed. This excess is compared with that predicted by quantum chromodynamics for the decay of the ψ into a γ and two gluons.

4 data tables
Table 1

THE STATISTICAL AND SYSTEMATIC ERRORS ARE GIVEN SEPARATELY AS WELL AS COMBINED IN QUADRATURE FOR THE QUOTED TOTAL ERROR.

Table 2

THE STATISTICAL AND SYSTEMATIC ERRORS ARE GIVEN SEPARATELY AS WELL AS COMBINED IN QUADRATURE FOR THE QUOTED TOTAL ERROR. SYSTEMATIC ERROR IS 17 PCT.

Table 3

QUOTED ERRORS ARE STATISTICAL. SYSTEMATIC ERROR IS 20 PCT. ONLY HALF THE SUM OF THE PI+ AND PI- CROSS SECTIONS IS PLOTTED IN THE FIGURE IN THE JOURNAL.

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Study of the Reaction $\bar{\nu} p \to \mu^+ p \pi^-$

Barish, S.J. ; Brock, R. ; Engler, A. ; et al.
Phys.Lett.B 91 (1980) 161, 1980.
Inspire Record 8430 DOI 10.17182/hepdata.51335

We present data on the reaction ν p → μ + pπ − from an exposure of the Fermilab 15 ft hydrogen bubble chamber. The channel cross section for 5 GeV < E ν < 70 GeV and M( p π − ) < 1.9 GeV is σ = (27 ± 5) × 10 −40 cm 2 . This cross section is dominated by the I = 1 2 production amplitude.

1 data table
Table 1

No description provided.


Electroproduction of $\pi^+ n$, $\pi^- p$ and $K^+ \Lambda$, $K^+ \Sigma^0$ Final States Above the Resonance Region

Brauel, P. ; Canzler, T. ; Cords, D. ; et al.
Z.Phys.C 3 (1979) 101, 1979.
Inspire Record 142872 DOI 10.17182/hepdata.15909

The reactionsΣvp→π+n,K+Λ,K+∑0 andΣvn→π+n were studied at invariant hadronic masses around 2.2. GeV forQ2=0.06, 0.28, 0.70, and 1.35 GeV2. The main results are: At small |t| the π+ production is dominated by longitudinally polarized photons and can be described by one pion exchange. At low |t| the transverse (π+n) cross section drops steeply withQ2, but remains roughly constant forQ2≧0.5 GeV2. For |t⊢≧0.8 GeV2, (π+n/dt) is almost independent ofQ2. The integrated cross section (π+n) shows a similarQ2-dependence asσtot (γvp) forQ2≧0.28 GeV2. The ratioσ(π-p)/σ(π+n) atQ2=0.70 and 1.35 GeV2 for |t|≧0.6 GeV2 is smaller than in photoproduction and close to 1/4. The ratioσ(K+∑0 decreases steeply withQ2 following roughly the predictions of the quark-parton model.

28 data tables
Table 1

PHI AND EPSILON DEPENDENCE FITTED TO GIVE COMPONENTS OF CROSS SECTION.

Table 2

No description provided.

Table 3

No description provided.

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Experimental Proof of the Existence of the A1 Meson

The ACCMOR collaboration Daum, C. ; Hertzberger, L. ; Hoogland, W. ; et al.
Phys.Lett.B 89 (1980) 281-284, 1980.
Inspire Record 143044 DOI 10.17182/hepdata.27272

In partial wave analyses of the ( π − π − π + ) system, substantial shape changes of the 1 + S ( ϱπ ) intensity as a function of t , and relative phase changes of ≈ 90°, provide compelling evidence for a resonant A 1 of mass ≈ 1280 MeV and width ≈ 300 MeV.

1 data table
Table 1

No description provided.


3 $\pi$ Resonances in 2- Partial Waves

The ACCMOR collaboration Daum, C. ; Hertzberger, L. ; Hoogland, W. ; et al.
Phys.Lett.B 89 (1980) 285-289, 1980.
Inspire Record 143045 DOI 10.17182/hepdata.27275

The J PC = 2 −+ partial wave intensities and their large phase changes prove the resonant nature of the A 3 meson (mass ≈ 1670 MeV, width ≈ 210 MeV). The decay modes are f 0 π , ϱ 0 π , and ϵ 0 π . Evidence is found for a further 2 − enhancement.

1 data table
Table 1

No description provided.


A2 Meson Production at 63-{GeV} and 94-{GeV} in the Reaction $\pi^- p \to \pi^- \pi^- \pi^+ p$

The ACCMOR collaboration Daum, C. ; Hertzberger, L. ; Hoogland, W. ; et al.
Phys.Lett.B 89 (1980) 276-280, 1980.
Inspire Record 143255 DOI 10.17182/hepdata.27274

The A 2 meson is studied in the decay mode ϱ 0 π − using partial wave analyses of 600 000 events from the reaction π − p→ π − π − π + p at 63 and 94 GeV incident momentum. Common production mechanisms are indicated for this resonance and diffractive 1 + and 2 − components.

1 data table
Table 1

No description provided.


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.