Measurement of the Reaction $\gamma \gamma \to \rho^+ \rho^-$ With the Cello Detector

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Phys.Lett.B 218 (1989) 493-498, 1989.
Inspire Record 267081 DOI 10.17182/hepdata.29842

Results on the reaction γγ → π + π − π 0 π 0 are presented. There is clear evidence for correlated ϱ + ϱ − production. The cross section is much lower than for γγ → ϱ 0 ϱ 0 .

2 data tables

Results using 3 parameter fit (rho+ rho-, rho+- pi+- pi0, and non-resonant 4pi) to data.

Results using 2 parameter fit (rho+ rho-, and non-resonant 4pi) to data.


S - $P$ Wave Interference in $K^+ K^-$ Photoproduction Near $K^+ K^-$ Threshold

Fries, D.C. ; Heine, P. ; Hirschmann, H. ; et al.
Nucl.Phys.B 143 (1978) 408-416, 1978.
Inspire Record 130050 DOI 10.17182/hepdata.34981

A mass-dependent asymmetry was observed in the decay angular distribution of a photoproduced K + K − system near the K + K − threshold. The corresponding moments 〈 Y 1 0 〉 have been evaluated. Interpreting the asymmetry as an S-P wave interface due to the states S 993 ∗ (0 + ) and ø 1019 (1 − ) one can compute the moments 〈 Y 1 0 〉 through an amplitude analysis. The theoretical calculation reproduces the experimental results well, if one assumes a real S-wave amplitude for the S 993 ∗ . The data cannot be explained by a non-resonant real S-wave. Other possibilities have been discussed. An estimate of the photoproduction cross section of the S ∗ → K + K − can be given on the basis of the above hypothesis.

1 data table

No description provided.


Elastic and Inelastic $\phi$ - Photoproduction

Behrend, H.-J. ; Bodenkamp, J. ; Hesse, W.P. ; et al.
Nucl.Phys.B 144 (1978) 22-60, 1978.
Inspire Record 130415 DOI 10.17182/hepdata.34982

The differential cross section of the reaction ( γ p → p φ ) has been measured in the t range 0 ⩽ t ⩽ 0.4 GeV 2 and for photon energies from 3.0 to 6.7 GeV. In particular for the small t region the measurement accuracy was better than 10%. We obtained for the slope parameter B in an exponential parametrization of the differential cross section d σ /d t = A e − Bt values of B ⋍ 6 ± 0.5 GeV −2 which are significantly larger than the slopes obtained by most other experiments at higher t values. This indicates a t dependence of B particularly in the small t region.

5 data tables

No description provided.

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Photoproduction of phi Mesons at Small t Values

Behrend, H.-J. ; Bodenkamp, J. ; Hesse, W.P. ; et al.
Phys.Lett.B 56 (1975) 408-412, 1975.
Inspire Record 98876 DOI 10.17182/hepdata.27859

The reaction γ + p → Φ + p has been measured using a spark chamber spectrometer and a tagged photon beam in the energy range from 4.6 to 6.7 GeV. Approximately 3500 photoproduced elastic Φ-events have been collected in the t -range between t min and t = −0.4 (GeV/ c ) 2 . Cross sections and t -distributions are presented.

1 data table

NO MARKED ENERGY DEPENDENCE.


MEASUREMENT OF THE REACTION gamma p ---> p anti-p p AT PHOTON ENERGIES 4.7-GeV <= E (gamma) <= 6.6-GeV

Bodenkamp, J. ; Fries, D.C. ; Markou, A. ; et al.
Nucl.Phys.B 255 (1985) 717-746, 1985.
Inspire Record 15090 DOI 10.17182/hepdata.33786

An experimental investigation of the reaction γ p → p p p at photon energies 4.7 ⩽ E γ ⩽ 6.6 GeV is described. The main results are the measurement of the cross section as a function of energy, a discussion of the main dynamical features of the reaction and the observation of a narrow p p mass state at 2.024 ± 0.005 GeV with a width of 29 ± 13 MeV.

3 data tables

OBSERVATION OF THIS CHANNEL AS A CONSISTENCY CHECK ON THE NORMALIZATION.

No description provided.

MEASUREMENTS OF CROSS SECTIONS OF MASS SIGNALS AT 1.94 AND 2.024 GEV, EVALUATE BY FITTING TWO BREIT WIGNERS AND CONSTANT BACKGROUND TO (AP P) MASS SPECTRUM. ERRORS ARE STATISTICAL ONLY.


Global Properties of Pion Production in the Reaction $\gamma \gamma \to 3 \pi^+ 3 \pi^-$

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Field, J.H. ; et al.
Phys.Lett.B 245 (1990) 298-304, 1990.
Inspire Record 296189 DOI 10.17182/hepdata.29695

We have studied the properties of pion production in the reaction γ →3 π + 3 π − in the energy range 1.6⩽ W γγ ⩽7.5 GeV with the CELLO detector at PETRA. We present the topological cross section both for Q 2 ≈0 (anti-tag) and Q 2 ≈0 (single-tag). The Q 2 dependence of the cross section is flatter than the GVDM prediction. The distribution of the production angle of the pions in the CMS peaks at small angles, indicating a peripheral process. In accordance with the VDM picture the p T distribution of the pions manifests an exponential fall-off. Like sign pion pairs were found to be Bose-Einstein correlated. We use this correlation to estimate the spatial dimensions of the interaction region.

7 data tables

No description provided.

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Cross-section and $p \bar{p}$ Invariant Mass Distribution of the Reaction $\gamma p \to p \bar{p} p$ at 4.7-{GeV} $\le e \gamma \le$ 6.6-{GeV}

Bodenkamp, J. ; Fries, D.C. ; Markou, A. ; et al.
Phys.Lett.B 133 (1983) 275-278, 1983.
Inspire Record 10564 DOI 10.17182/hepdata.30612

Cross section and pp¯ in variant mass distribution of the reaction γp→pp¯p are presented. Further evidence for a narrow pp¯ mass state at 2.023 GeV will be given.

3 data tables

Axis error includes +- 0.0/0.0 contribution (?////SYSTEMATIC ERRORS HAVE BEEN FOLDED IN QUADRATURE WITH STATISTICAL ERRORS).

Axis error includes +- 0.0/0.0 contribution (?////SYSTEMATIC ERRORS HAVE BEEN FOLDED IN QUADRATURE WITH STATISTICAL ERRORS).

Axis error includes +- 0.0/0.0 contribution (?////SYSTEMATIC ERRORS HAVE BEEN FOLDED IN QUADRATURE WITH STATISTICAL ERRORS).


Experimental Study of the Hadronic Photon Structure Function

The CELLO collaboration Behrend, H.J. ; Fenner, H. ; Gumpel, U. ; et al.
Phys.Lett.B 126 (1983) 391-397, 1983.
Inspire Record 198110 DOI 10.17182/hepdata.30720

We have measured at PETRA the process e γ → e + hadrons at an average Q 2 value of 9 GeV 2 / c 2 . The total number of observed events attributed to this process is 215. Our data are compared to calculations based on the estimation of the photon structure function F 2 in the quark parton model and in QCD.

1 data table

No description provided.


Rho0 production in the reaction gamma gamma ---> 3 pi+ 3 pi- and search for gamma gamma ---> rho0 rho0 (1700)

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Field, J.H. ; et al.
Z.Phys.C 49 (1991) 43-48, 1991.
Inspire Record 27985 DOI 10.17182/hepdata.15027

We have studied the ρ0 production rate in the reaction ξξ→3π+3π− in the energy range 1.6≦Wγγ≦7.5 GeV with the CELLO detector at PETRA. Our analysis points to a substantial yield of ρ0ρ0π+π− events in particular atWγγ>4.0 GeV. We give cross sections for the ρ02π+2π− and ρ0ρ0π+π− final states and calculate upper limits for the reaction γγ→ρ0ρ0 (1700) →ρ0ρ0π+π−.

3 data tables

Data from CA model analysis.

Data from NCA model analysis.

Upper limits to RHO0 RHO(1700)0 cross section with 95 pct confidence limits. Data read from graph.


$K^0(s$) $K \pi$ Production in Tagged and Untagged $\gamma \gamma$ Interactions

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Z.Phys.C 42 (1989) 367, 1989.
Inspire Record 266414 DOI 10.17182/hepdata.15529

We have searched for resonance production in the reaction γγ→Ks0Kπ. No signal was found for theηc and an upper limit for the radiative with\(\Gamma _{\gamma \gamma }^{\eta _c } \) keV (95% c.l.) is obtained. For the glueball candidate η(1440) (previouslyi) the upper limit\(\Gamma _{\gamma \gamma }^{\eta (1440)} B(\eta (1440) \to K\bar K\pi )< 1.2keV(95\% c.l.)\) is derived. In the tagged data sample resonance formation of a spin 1 state at 1420 MeV is observed, which is absent in the untagged data. The mass and width of this state are consistent with those of thef1(1420); an analysis of decay angular distributions favours positive parity.

1 data table

Data read from graph.. Additional overall systematic error decreasing from 25% in the lowest mass bins to 15% for M > 2.0 GeV.