Behrend, H.J.
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Photoproduction of $\pi^0$ in the Backward Direction

Buschhorn, G. ; Heide, P. ; Kotz, U. ; et al.
Phys.Rev.Lett. 20 (1968) 230-232, 1968.
Inspire Record 54459 DOI 10.17182/hepdata.21735

None

1 data table
Table 1

No description provided.


Hadron Production From Photon - Photon Interactions in the Center-of-mass Energy Range From 1-{GeV} to 5-{GeV}

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Grigull, R. ; et al.
Phys.Lett.B 89 (1979) 120-124, 1979.
Inspire Record 142875 DOI 10.17182/hepdata.27291

We present the first data on photon-photon annihilation into hadrons for CM energies > 1 GeV obtained with the detector PLUTO at the e + e − storage ring PETRA. Cross sections are extracted using an inelastic eγ scattering formalism. The results are compared to expectations from Regge-like models.

1 data table
Table 1

DEPENDENCE OF CROSS SECTION FOR ELECTRON-PHOTON SCATTERING (ANALOGOUS TO HAND'S FORMULA) ON VISIBLE HADRONIC ENERGY, CALCULATED BY TAKING PION MASSES FOR ALL CHARGED PARTICLES.


A STUDY OF THE REACTIONS ANTI-K0 P ---> LAMBDA PI+ (BACKWARD) AND ANTI-K0 P ---> SIGMA0 PI+ (BACKWARD) FOR KAON MOMENTA BETWEEN 1 AND 8-GEV/C

Bamberger, A. ; Bruning, H. ; Brundiers, H.J. ; et al.
Nucl.Phys.B 174 (1980) 277-299, 1980.
Inspire Record 159454 DOI 10.17182/hepdata.34465

We present results for the reactions K 0 p →Λπ + and K 0 p →∑ 0 π + , for |u'| <0. 05 ( GeV /c) 2 and kaon momenta between 1 and 8 GeV/ c . The experiment was performed ina neutral beam at the PS with a two arm spark chamber spectrometer. The cross sections show strong dependence on beam energy and momentum transfer u ′. Λ polarization is compatible with zero. We compare energy dependence of the backward cross sections with the baryon exchange model from π N scattering.

8 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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INELASTIC ELECTRON PHOTON SCATTERING AT MODERATE FOUR MOMENTUM TRANSFERS

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Grigull, R. ; et al.
Phys.Lett.B 99 (1981) 287-291, 1981.
Inspire Record 155594 DOI 10.17182/hepdata.27125

We present new high statistics data on hadron production in photon-photon reactions. The data are analyzed in terms of an electron-photon scattering formalism. The dependence of the total cross section of Q 2 , the four-momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector-Meson Dominance and the quark model.

3 data tables
Table 1

No description provided.

Table 2

DEPENDENCE ON VISIBLE HADRONIC INVARIANT MASS.

Table 3

Data read from graph.


PHOTOPRODUCTION OF CHARGED PIONS FROM DEUTERIUM AT GAMMA ENERGIES FROM 900-MEV TO 1800-MEV AND PION ANGLES BETWEEN 65-DEGREES AND 125-DEGREES

Besch, H.j. ; Krautschneider, F. ; Sternemann, K.p. ; et al.
Z.Phys.C 16 (1982) 1-6, 1982.
Inspire Record 184969 DOI 10.17182/hepdata.16386

π−-photoproduction cross sections from neutrons have been measured with a deuterium target at effective γ-energies from 900 to 1,800 MeV and pion centre-of-mass angles 65 to 125°. The outgoing pion and proton were detected in coincidence, the pion with a magnetic spectrometer and the proton with a time-of-flight system. To test the reliability of the analysis method, a comparison of π+-photoproduction from protons and deuterons was made with a slightly modified apparatus. It was found adequate to use the spectator model with a Huthèn wave function.

1 data table
Table 1

No description provided.


Measurement of the Reaction gamma gamma ---> pi+ pi+ pi- pi- at PETRA

The CELLO collaboration Behrend, H.J. ; Fenner, H. ; Schachter, M.J. ; et al.
Z.Phys.C 21 (1984) 205, 1984.
Inspire Record 191578 DOI 10.17182/hepdata.16344

We have determined the cross section for γγ→π+π+π−π− in a way free of assumptions about the relative contributions fromρ0ρ0,ρ02π and 4π (uncorrelated phase space). We find a sharp onset above threshold and a rather high cross section of about 200 nb aroundWγγ=1.5 GeV which consists to about 40% ofρ0ρ0 production with sizeable contributions fromρ02π and 4π (PS). The total cross section as well as theρ0ρ0 content fall rather fast at higher c.m. energies. Attempts to explain this behaviour in terms of production of known resonances are not successful so far. The angular distributions do not show any significant structure pointing to resonance formation in the 4π-system. Only theρ0-meson is observed in the moment analysis. The decay distributions of theρ0 for forward produced rhos are fairly consistent with helicity conservation of the produced rhos in accordance with the VDM picture.

5 data tables
Table 1

No description provided.

Table 2

RESULTS OF DECOMPOSITION OF THE CROSS SECTION INTO RHO RHO, RHO 2PI, AND 4PI(PHASE SPACE) USING TWO WIDE W BINS. SEE TEXT OF PAPER FOR DISCUSSION OF FITS.

Table 3

RESULTS OF DECOMPOSITION OF THE CROSS SECTION INTO THE RHO RHO, RHO PI, AND 4PI (PHASE SPACE) USING SMALL W BINS. SEE TEXT OF PAPER FOR DISCUSSION OF FITS.

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Study of the Reaction $\gamma \gamma \to 2 \pi^+ 2 \pi^- \pi^0$ and Upper Limits on the Production of $\gamma \gamma \to \omega \omega$ and $\gamma \gamma \to \rho^0 \omega$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 29 (1985) 183, 1985.
Inspire Record 220911 DOI 10.17182/hepdata.15911

A search for the reactionsγγ→ωω andγγ→ρ0ω has been carried out at an averagee+e− CM energy of 34.6 GeV with an integrated luminosity of 45 pb−1. Upper limits are set for these two channels over the γγ CM Energy range of 1.6 to 2.5 GeV. The cross section is determined for the exclusive channelγγ→π+2π−π0.

3 data tables
Table 1

Data read from graph.

Table 2

Data read from graph.

Table 3

Data read from graph.


Tensor Meson Excitation in the Reaction $\gamma \gamma \to K^0_S K^0_S$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 37 (1988) 329, 1988.
Inspire Record 250982 DOI 10.17182/hepdata.15690

In the analysis of the reactione+e−→e+e−KS0Ks0 clear evidence for exclusive γγ→f2′ resonance production is observed. The productΓγγ ·B(f2′→K\(\bar K\)) is measured to be 0.10−0.03−0.02+0.04+0.03 keV independent of ana priori assumption on the helicity structure. Our data are consistent with a pure helicity 2 contribution and we derive an upper limit for the ratioΓγγ(0)/Γγγ. The absence of events in the mass region around 1.3 GeV clearly proves destructivef2−a2 interference and allows to measure the relative phases betweenf2,a2 andf2′. Upper limits on the production of the glueball candidate statesf2(1720) andX(2230) as well as theKS0KS0-continuum are given.

1 data table
Table 1

Data read from graph.


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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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.