Ansorge, R.E.
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Inclusive and Semiinclusive $\rho^0$ Production in $\pi^+ / \pi^- / K^+ / P P$ Interactions at 147-{GeV}/$c$

Schouten, M. ; De Bock, H. ; Dziembowski, Z. ; et al.
Z.Phys.C 9 (1981) 93-104, 1981.
Inspire Record 170594 DOI 10.17182/hepdata.1419

In an experiment with the 30-inch Hybrid Spectrometer at Fermilab we have obtained the inclusive and semi-inclusive production cross sections of the ϱ0 meson using a conventional background subtraction technique. Production cross sections for the ϱ0 are derived as a function of the Feynman scaling variablex, and the transverse variablespt2 andEt=(pt2+M2)1/2. The longitudinal distributions are compared with the (1−x) dependence of the proton and meson valence quark structure functions, using various forms of recombination and fragmentation models. The transverse distributions are compared with thermodynamic models. We give density matrix elements for the ϱ0 production from pions in the extreme forward region.

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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RESONANCE PRODUCTION BY TWO PHOTON INTERACTIONS AT SPEAR

Jenni, P. ; Burke, D.L. ; Telnov, Valery I. ; et al.
Phys.Rev.D 27 (1983) 1031, 1983.
Inspire Record 173430 DOI 10.17182/hepdata.23843

Two-photon interactions have been studied with the SLAC-LBL Mark II magnetic detector at SPEAR. The cross section for η′ production by the reaction e+e−→e+e−η′ has been measured at beam energies from 2.0 to 3.7 GeV. The radiative width Γγγ(η′) has been determined to be 5.8±1.1 keV (±20% systematic uncertainty). Upper limits on the radiative widths of the f(1270), A2(1310), and f′(1515) tensor mesons have been determined. A search has been made for production of the E(1420) by γγ collisions, but no signal is observed.

2 data tables
Table 1

No description provided.

Table 2

NO SIGNAL ABOVE BACKGROUND SEEN. UPPER LIMITS AT 95 PCT CL GIVEN.


Pion Pair Production in Photon - Photon Collisions at {SPEAR}

Roussarie, A. ; Burke, D.L. ; Abrams, G.S. ; et al.
Phys.Lett.B 105 (1981) 304-308, 1981.
Inspire Record 166578 DOI 10.17182/hepdata.31056

We report a measurement of the cross section for the process γγ → π + π − at invariant masses 500 MeV/ c 2 < m ππ <2000 MeV/ c 2 . A value for the radiative width of the f(1270) tensor meson Γ f→ γγ = 3.6 ± 0.3 ± 0.5 KeV (helicity λ = 2) has been obtained from a fit to the observed ππ mass spectrum.

1 data table
Table 1

DATA REQUESTED FROM AUTHORS.


Evidence for a High Mass Enhancement in $K^+ K^-$ Photoproduction

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Phys.Lett.B 104 (1981) 231-234, 1981.
Inspire Record 165081 DOI 10.17182/hepdata.31068

The reaction γ p → K + K − p has been investigated with tagged photons in the energy range of 20 < E γ < 70 GeV. A structure in the 1.7 GeV mass region is observed and interpreted in terms of a recurrence of the ø.

1 data table
Table 1

No description provided.


The Reaction $\gamma p \to p \pi^+ \pi^- \pi^+ \pi^-$ for Photon Energies From 25-{GeV} to 70-{GeV}

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Nucl.Phys.B 189 (1981) 15-39, 1981.
Inspire Record 164533 DOI 10.17182/hepdata.34258

Measurements of the reaction γ p → p π + π − π + π − are presented, in which π + π − π + π − systems with masses up to 3 GeV are produced from fragmentation of the incident photon. The reaction is dominated by production of the large peak of the ϱ′(1600) meson and, at higher masses ≳2 GeV, y production of jet-like 4 π systems. The ϱ′(1600) meson is produced by a predominantly s -channel helicity conserving mechanism. At higher masses there are also indications of ϱπ peaks, of masses 1.3 GeV (the A 2 meson) and 1.75 GeV, produced with a recoiling π meson by a mechanism consistent with the Deck effect.

1 data table
Table 1

CORRECTED FOR TAILS OF BREIT-WIGNER RESONANCE USED IN FIT AND ALLOWING FOR 10 PCT BACKGROUND.


A Measurement of the Cross-Section for Four Pion Production in gamma gamma Collisions at SPEAR

Burke, D.L. ; Abrams, G.S. ; Alam, M.S. ; et al.
Phys.Lett.B 103 (1981) 153-156, 1981.
Inspire Record 165016 DOI 10.17182/hepdata.31168

We present a measurement of the cross section for the reaction e + e − → e + e − π + π − π + π − at SPEAR. This channel is found to be large and dominated by the process γγ → ϱ 0 ϱ 0 → π + π − π + π − . The cross section, which is small just above the four-pion threshold, exhibits a large enhancement near the ϱ 0 ϱ 0 threshold.

1 data table
Table 1

Axis error includes +- 0.0/0.0 contribution (THE QUOTED ERRORS INCLUDE VARIOUS SYSTEMATIC ERRORS ADDED QUADRATICALLY).


Production of S = -2 and -3 Baryon States in 6.5-{GeV}/$c K^- P$ Interactions

Hassall, J.K. ; Ansorge, R.E. ; Carter, J.R. ; et al.
Nucl.Phys.B 189 (1981) 397-420, 1981.
Inspire Record 172448 DOI 10.17182/hepdata.34253

We present results from a high statistics (46 events/μ;b) experiment on K − p interactions in the Argonne 12 foot bubble chamber. In particular we make a systematic search for Ξ ∗ resonances. We confirm recent evidence of a Ξ(2370), and see a number of other well established states. We also give cross sections for various exclusive and inclusive reactions, including those in which θ − are produced.

1 data table
Table 1

THE PI0 ARE UNDETECTED.


The Effective Energy Dependence of the Charged Particle's Multiplicity in $P / \pi^+ / K^+$ Interactions on Protons at 147 GeV/c

Brick, D. ; Rudnicka, H. ; Shapiro, A.M. ; et al.
Phys.Lett.B 103 (1981) 241-246, 1981.
Inspire Record 170358 DOI 10.17182/hepdata.6707

The energy dependence of the average of the charged multiplicity and its dispersion in π + /K + /p interaction on protons at 147 GeV/ c is found to be the same as in e + e − annihilations if an “effective energy” variable is used instead of the total energy. The effective energy S eff is defined as the invariant mass of all secondaries left after the two leading particles have been removed. Fitting the expression aS eff b to the average charge multiplicity 〈 n ch 〉, we find the power b to be in good agreement with the value of 0.25 predicted by Fermi's statistical model and by Landau's hydrodynamical model.

6 data tables
Table 1

BINS IN WEFF SELECTED SO AS TO YIELD 200 EVENTS IN EACH BIN.

Table 2

200 EVENTS IN EACH BIN IN WEFF.

Table 3

50 EVENTS IN EACH BIN IN WEFF.

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Photoproduction of Charmed F Mesons at $\gamma$ Energies of 20-{GeV} to 70-{GeV}

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Phys.Lett.B 100 (1981) 91-94, 1981.
Inspire Record 155586 DOI 10.17182/hepdata.31208

Evidence is presented for inclusive photoproduction of F ± mesons in three decay modes, ηπ ± , ηπ ± π + π − and ηπ ± π + π + π − π − . The average mass of the F ± is found to be 2.020±0.010 GeV.

1 data table
Table 1

No description provided.


Polarization of Muoproduced J/psi (3100)

Clark, A.R. ; Johnson, K.J. ; Kerth, L.T. ; et al.
Phys.Rev.Lett. 45 (1980) 2092, 1980.
Inspire Record 155741 DOI 10.17182/hepdata.20697

The polarization and Q2 dependence of muoproduced ψ→μ+μ− have been analyzed in a magnetized-steel calorimeter at Fermilab. The reaction γVN→ψN is found to be helicity conserving. Even after allowance for possible Q2 dependence of the decay angular distribution, the ψ muoproduction cross section falls more steeply in Q2 than predicted by ψ dominance.

4 data tables
Table 1

EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.

Table 2

EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.

Table 3

EFFECTIVE CROSS SECTION IN ARBITRARY UNITS.

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