Measurement of the polarization of the recoil protons from the reaction $\gamma + \rho \rightarrow \rho + \pi^0$ in the region of the second resonance at low pion center of mass angles

Trines, Dieter ; Althoff, K.H. ;
PhD Thesis, Bonn U., Math. Inst., 1972.
Inspire Record 1396209 DOI 10.17182/hepdata.37154

None

1 data table match query

No description provided.


Photoproduction of Negative Pions on a Polarized Neutron Target in the Resonance Region

Althoff, K.H. ; Beckschulze, H. ; Conrad, R. ; et al.
Nucl.Phys.B 96 (1975) 497-508, 1975.
Inspire Record 99642 DOI 10.17182/hepdata.31932

At the Bonn 2.5 GeV electron synchrotron the first measurements of the target asymmetry for the reaction γ + n ↑ → π − + p have been performed. The negative pions were detected in a magnetic spectrometer at a constant pion c.m. angle of 40° and photon energies between 0.45 GeV and 2.0 GeV. Deuterated butanol was used as target material. The polarization of the deuterons was about 16%. The results show a significant difference from the previously measured π + asymmetry.

1 data table match query

No description provided.


Photoproduction of pi+ mesons on polarized protons at photon energies between 0.5 and 2.2 gev

Althoff, K.H. ; Feller, P. ; Herr, H. ; et al.
Nucl.Phys.B 53 (1973) 9-18, 1973.
Inspire Record 84220 DOI 10.17182/hepdata.32593

The target asymmetry T = ( σ ↑ − σ ↓)/( σ ↑ + σ ↓) for the reaction γ p → π + n has been measured at the Bonn 2.5 GeV electron synchrotron for a pion c.m. angle of 40° and γ energies between 0.5 and 2.2 GeV. Butanol was used as the target material. About 35% of the protons could be polarized using the dynamic-polarization method in a continuous-flow cryostat operating at 1°K and 25 kG. The π + mesons were detected in a magnetic-spectrometer system. Considerable structure in the asymmetry was observed.

1 data table match query

Axis error includes +- 11/11 contribution.


Positive Pion Photoproduction From Hydrogen at Photon Energies Between 500-{MeV} and 1400-{MeV} in Forward Direction

Althoff, K.H. ; Anton, G. ; Bock, B. ; et al.
Z.Phys.C 18 (1983) 199, 1983.
Inspire Record 189703 DOI 10.17182/hepdata.16352

The differential cross section of the reactionγ+p→π+ was measured at pion CM-angles of 20° and 30° for photon energies between 500 MeV and 1,400 MeV. The pions were detected in a magnetic spectrometer. By measuring each pion trajectory and by offline calculation of the initial pion parameters an energy resolution of about 2.5% FWHM was achieved. The results complete a set of data which were measured in recent years at the Bonn 2.5 GeV synchrotron. In comparison to photoproduction analyses two effects were revealed: The η cusp appears in the energy dependence of the cross section as a sharp drop atKγ=710 MeV. In the region of the third resonance the data show a greater enhancement than predicted by most of the analyses.

1 data table match query

No description provided.


Production of $K \bar{K}$ Pairs in Photon-photon Collisions and the Excitation of the Tensor Meson F-prime (1515)

The TASSO collaboration Althoff, M. ; Brandelik, R. ; Braunschweig, W. ; et al.
Phys.Lett.B 121 (1983) 216-222, 1983.
Inspire Record 181468 DOI 10.17182/hepdata.30814

We have observed exclusive production of K + K − and K S O K S O pairs and the excitation of the f′(1515) tensor meson in photon-photon collisions. Assuming the f′ to be production in a helicity 2 state, we determine Λ( f ′ → γγ) B( f ′ → K K ) = 0.11 ± 0.02 ± 0.04 keV . The non-strange quark of the f′ is found to be less than 3% (95% CL). For the θ(1640) we derive an upper limit for the product Λ(θ rarr; γγ K K ) < 0.03 keV (95% CL ) .

2 data tables match query

Data read from graph.. Errors are the square roots of the number of events.

Data read from graph.. Errors are the square roots of the number of events.


Measurement of the Radiative Width of the A(2) (1320) in Two Photon Interactions

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gerhards, R. ; et al.
Z.Phys.C 31 (1986) 537, 1986.
Inspire Record 228876 DOI 10.17182/hepdata.15859

The reactione+e−→e+e− A2 (1320) has been observed by detecting the decayA2→π+,π-π0. The two-photon width of theA2 has been measured to be Г(A2→γγ)=(0.09±0.27 (stat)±0.16 (syst)) keV. The cross section σ(γγ→π+,π-π0 has been determined outside theA2 resonance region.

1 data table match query

Data read off a graph.


Search for Two Photon Production of Resonances Decaying Into $K \bar{K}$ and $K \bar{K} \pi$

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Kirschfink, F.J. ; et al.
Z.Phys.C 29 (1985) 189, 1985.
Inspire Record 220941 DOI 10.17182/hepdata.16018

An analysis of the production ofKS0KS0 andK±Ks0π∓ by two quasi-real photons is presented. The cross section forγγ→K0\(\overline {K^0 } \), which is given for the γγ invariant mass range fromK\(\bar K\) threshold to 2.5 GeV, is dominated by thef′(1525) resonance and an enhancement near theK\(\bar K\) threshold. Upper limits on the product of the two-photon width times the branching ratio intoK\(\bar K\) pairs are given forΘ(1700),h(2030), and ξ(2220). For exclusive two-photon production ofK±Ks0π∓ no significant signal was observed. Upper limits are given on the cross section ofγγ→K+\(\overline {K^0 } \)π− orK−K0π+ between 1.4 and 3.2 GeV and on the product of the γγ width times the branching ratio into theK\(\bar K\)π final states for theηc(2980) and the ι(1440), yieldingΓ(γγ)→i(1440))·BR(i(1440)→K\(\bar K\)π<2.2 keV at 95% C.L.

1 data table match query

Data read from graph.. Corrected for the angular distribution, which is assumed to be sin(theta)**4 for W > 1.14 GeV and isotropic in the first bin.


a_1(1260) dominance in the process e+e- \to 4\pi at energies 1.05--1.38 GeV

The CMD-2 collaboration Akhmetshin, R.R. ; Anashkin, E.V. ; Arpagaus, M. ; et al.
Phys.Lett.B 466 (1999) 392-402, 1999.
Inspire Record 483994 DOI 10.17182/hepdata.50145

First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to \pi^+\pi^- 2\pi^0 and e+e- \to 2\pi^+ 2\pi^- has been measured. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Upper limits for the contributions of other alternative mechanisms are also placed.

3 data tables match query

Energy dependence of the cross section for the 2PI+ 2PI- final state. Statistical errors only.

Energy dependence of the cross section for the PI+ PI- 2PI0 final state. Statistical errors only.

Energy dependence of the cross section for the OMEGA PI0 final state. Statistical errors only.


Differential Cross-Sections for the pi0 Photoproduction at Theta (CM) = 90-Degrees and K (Lab) = 380-MeV-820-MeV

Jung, M. ; Kattein, J. ; Leu, P. ; et al.
BONN-HE-76-15, 1976.
Inspire Record 111677 DOI 10.17182/hepdata.50235

None

1 data table match query

No description provided.


Left-right Asymmetry in Inverse $\pi^-$ Photoproduction From a Transversely Polarized Proton Target

Kim, G.J. ; Adrian, S.D. ; Arends, J. ; et al.
Phys.Rev.Lett. 56 (1986) 1779-1782, 1986.
Inspire Record 232117 DOI 10.17182/hepdata.20259

Accurate measurements of the left-right asymmetry in π−p→γn at pπ=427−625 MeV/c with a transversely polarized target are reported. Results are compared with the predictions from the Arai and Fujii single-pion photoproduction partial-wave analysis and with data on the inverse process measured with a deuterium target. The agreement is poor, casting doubt on the correctness of the value for the radiative-decay amplitude of the neutral Roper resonance now in use.

3 data tables match query

No description provided.

No description provided.

No description provided.