Dainton, J.B.
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Measurement and Analysis of the Reaction $\gamma \gamma \to \pi^+ \pi^- \pi^+ \pi^-$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 38 (1988) 521, 1988.
Inspire Record 252632 DOI 10.17182/hepdata.1916

We have measured the cross section of four charged pion production in photon-photon interactions in the invariant mass range 1.0≦Wγγ≦3.2 GeV and up toQ2=16 GeV2. For 1.2 GeV≦Wγγ≦1.7 GeV the process is dominated by ρ0ρ0 production with a rapid rise in cross section around 1.2 GeV, well below the nominal ρ0ρ0 threshold. The observed distributions in the two particle masses and in the production and decay angles are well described by an incoherent sum of the phase-space subprocesses γγ →ρ0ρ0, →ρ0π+π−, and →π+π−π+π−. A spin-parity analysis of the ρ0ρ0 system showsJP=2+ to dominate, although 0+ is also possible forWγγ≦1.4 GeV. Negative partity states are excluded.

12 data tables
Table 1

Fractions of subprocesses from 3-parameter fit to the no-tag data.

Table 2

Fractions of subprocesses from 2-parameter fit to the no-tag data in limited energy range. The Q=1R contribution is set equal to zero.

Table 3

Fractions of subprocesses from 3-parameter fit to the single-tag data.

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Direct Photon Production in Proton - Anti-proton Interactions at $\sqrt{s}=24$.3-{GeV}

The UA6 collaboration Bernasconi, A. ; Breedon, R.E. ; Camilleri, L. ; et al.
Phys.Lett.B 206 (1988) 163-168, 1988.
Inspire Record 261244 DOI 10.17182/hepdata.29982

Direct photons have been studied in pp̄ interactions at √ s = 24.3 GeV and in the transverse momentum ( p T ) range 3–7 GeV/ c (0.25 < x T < 0.58). The experiment was performed using an internal H 2 cluster the target in the CERN pp̄ Collider. The measured invariant cross section is compared with recent theoretical predictions.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


PHOTON DIFFRACTIVE DISSOCIATION TO rho rho pi AND rho pi pi pi STATES

The Omega Photon collaboration Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Z.Phys.C 38 (1988) 535, 1988.
Inspire Record 261249 DOI 10.17182/hepdata.48824

This paper reports studies of the reactions γp→ρ π π πp and γp→ρ ρ πp. In particular a peak is reported in the ρ ρ π mass spectrum with closely similar mass and width to those of the ω ρ π peak previously reported in the reaction γp→ω ρ πp. The ratio of production cross sections is found to be ρ ρ π/ω ρ π=0.96±0.19, in serious disagreement with the expectation from Vector Meson Dominance. A possible explanation is indicated.

2 data tables
Table 1

No description provided.

Table 2

Numerical values requested from authors.


Neutrino Counting With the Cello Detector and Search for Supersymmetric Particles

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Phys.Lett.B 215 (1988) 186-194, 1988.
Inspire Record 261670 DOI 10.17182/hepdata.22766

A search for single photons, produced in e + e − collisions together with particles interacting only weakly with matter, has been performed using the CELLO detector at the PETRA storage ring. We report on results from data taken at 35 GeV < √ s <46.57 GeV. An upper limit of 8.7 (90% CL) on the number of light neutrino species is set. Combining our result with published results from other e + e − experiments the number of light neutrinos is limited to N v < 4.6 at 90% CL. We also set lower limits on the masses of supersymmetric particles.

1 data table
Table 1

TWO RUN AT DIFFERENT ENERGIES COMBINED, 1.26 EVENTS WAS FOUND.


The $K^0_S K^0_S$ Final State in $\gamma \gamma$ Interactions

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Z.Phys.C 43 (1989) 91, 1989.
Inspire Record 267756 DOI 10.17182/hepdata.15432

In the reaction γγ→KS0KS0 resonance production of thef2− is observed. For the radiative with\(\Gamma _{\gamma \gamma } .B(f'_2\to K\bar K) = 0.11_{ - 0.02}^{ + 0.03}\pm 0.02keV\) is found. The small number of events in thef2,a2 mass region is consistent with the assumption of destructivef2−a2 interference. From the mass distribution we determine the relative phases between the tensor mesons. Upper limits on the radiative widths of the glueball candidatesf2(1720) andX (2220) are derived.

3 data tables
Table 1

Only bins containing events are included, all others are zero.. Untagged plus single events.. Data read from graph.

Table 2

Only bins containing events are included, all others are zero.. Untagged events.. Data read from graph.

Table 3

Corrected for the angular distribution, which is assumed to be sin(theta)**4. Additional systematic error decreasing from 20% in the lowest mass bins to 15% for W > 1.5 GeV.. Data read from graph.


Observation of Double $\phi$ Meson Production in the Central Region for the Reaction $p p \to p$(f) ($K^+ K^- K^+ K^-$) $p(s$) at 300-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Benayoun, Maurice ; Beusch, W. ; et al.
Phys.Lett.B 221 (1989) 221-226, 1989.
Inspire Record 276743 DOI 10.17182/hepdata.29825

The reaction pp→p f (K + K − K + K − )p s in which the K + K − K + K − system is centrally produced has been studied at 300 GeV/ c . φφ production has been observed and the ratio σ (φK + K − )/ σ ( φφ ) is 1.0±0.3. The cross section for central production of φφ is found to be the same at 300 GeV/ c and 85 GeV/ c . An angular analysis of the φφ system favours J P =2 + over 0 − .

1 data table
Table 1

No description provided.


A Spin Parity Analysis of the F(1) (1285) and F(1) (1420) Mesons Centrally Produced in the Reaction $p p \to p$(f) ($K^0_S K^\pm \pi^\mp$) at $p(s$) at 300-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Benayoun, Maurice ; Beusch, W. ; et al.
Phys.Lett.B 221 (1989) 216-220, 1989.
Inspire Record 276742 DOI 10.17182/hepdata.29828

Results are presented of an analysis of the reaction pp→p f (K S 0 K ± π ∓ )p s at 300 GeV/ c . Clear f 1 (1285) and f 1 (1420) signals are seen. A spin-parity analysis shows that both are consistent with being 1 ++ states. The f 1 (1420) is found to decay only to K ∗ K and no 0 −+ or 1 +− waves are required to describe the data. The production of the f 1 (1285) as a function of energy is not the same as that for the f 1 (1420) whose cross section is found to be constant with energy.

1 data table
Table 1

No description provided.


Study of the $\pi^+ \pi^+ \pi^- \pi^-$ System Centrally Produced by Incident $\pi^+$ and $p$ Beams at 85-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Bloodworth, I.J. ; Carney, J.N. ; et al.
Z.Phys.C 43 (1989) 55, 1989.
Inspire Record 276888 DOI 10.17182/hepdata.15434

The reactions π+p→π+(π+π+π-π-)p andpp→p(π+π+π-π-)p, where the (π+ π+ π- π-) system is centrally produced have been studied at 85 GeV/c. The π+π+π-π- mass spectrum shows evidence for thef1 (1285) meson with a mass of 1278±2 MeV and width 41±12 MeV which decays mainly through ρ0(770)π+π-. Thef1(1285) is also observed in the ηπ+π- channel. There is no significant evidence for ηππ or 4π decay modes of thef1(1420). The ρ0ρ0 production is found to be small. A Dalitz plot analysis of the 3π system shows evidence fora2 (1320) production and for a large contribution of theJPC=1++ ρπ wave.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


$\tau$ Production and Decay With the Cello Detector at {PETRA}

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Phys.Lett.B 222 (1989) 163-172, 1989.
Inspire Record 276859 DOI 10.17182/hepdata.29824

The reaction e + e − → τ + τ − has been studied at centre of mass energies between 14.0 and 46.8 GeV with the CELLO detector at the PETRA e + e − collider. We present results for the cross section σ τ and the charge asymmetry A τ . The results are in good agreement with the standard model. We have also measured the topological decay rates BR 1 , BR 3 and BR 5 for the inclusive decay of the τ lepton into one, three and five charge particles. The results confirm and improve earlier CELLO measurements at other energies. We find for the combined values at all energies BR 1 = (84.9 ± 0.4 ± 0.3)%, BR 3 = (15.0 ± 0.4 ± 0.3)% and BR 5 = (0.16 ± 0.13 ± 0.04)%.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

Corrected for radiative effects and background contributions.


Evidence for New States Produced in the Central Region in the Reaction $p p \to p$(f) ($\pi^+ \pi^- \pi^+ \pi^-$) $p(s$) at 300-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Benayoun, Maurice ; Beusch, W. ; et al.
Phys.Lett.B 228 (1989) 536-542, 1989.
Inspire Record 280165 DOI 10.17182/hepdata.29783

The reaction pp→p f ( π + π − π + π − )p s , where the π + π − π + π − system is centrally produced, has been studied at 300 GeV/ c in an experiment designed to search for gluonic states. The π + π − π + π − mass spectrum shows evidence for the f 1 (1285) with a mass of 1281±1 MeV and a width of 31±5 MeV. In addition there is evidence for two new enhancements at masses of 1449±4 and 1901±13 MeV with widths of 78±18 and 312±61 MeV respectively. An analysis of the state at 1.45 GeV indicates that it is not a π + π − π + π − decay mode of the f 1 (1420) or ι η(1440) .

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.