Date

Observation of A Meson x --> 2 gamma, with Mass 2.85-GeV/c**2, Produced in the Charge Exchange Reaction pi- p --> x n at 40-GeV/c

Apel, W.D. ; Augenstein, K.H. ; Bertolucci, E. ; et al.
Phys.Lett.B 72 (1978) 500-502, 1978.
Inspire Record 122151 DOI 10.17182/hepdata.27481

The invariant mass spectrum of neutral final states produced in π − p charge-exchange scattering at 40 GeV/ c has been studied, searching for heavy particles decaying in 2γ. A peak is observed around 2.85 GeV/ c 2 . The cross section of the reaction π − p→X(2.85)+n, times the branching ratio of the X→2 γ decay, is measured to be σ × BR ⋍ 2 × 10 −34 cm 2 .

1 data table

MEAN VALUE OF -T = 0.28 +- 0.04 GEV**2.


Investigation of pi- p --> pi0 n Reaction at Large Momentum Transfer

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Bertolucci, E. ; et al.
Phys.Lett.B 72 (1977) 132, 1977.
Inspire Record 121448 DOI 10.17182/hepdata.39780

New results on a high statistics measurement of pion-nucleon charge exchange scattering at 40 GeV/ c , extending in momentum transfer up to − t = 1.8 (GeV/ c ) 2 , are reported and compared with an optical impact parameter model, together with previous data for the reaction π − p → ηn at the same energy. The imaginary part of the pole trajectory b 0 ( s ) is determined from the slope of the tangent to the maxima of (−t) 1 2 d σ d t . The linear increase of Im b 0 ( s ) with log s , which has been observed at low energies, continues up to 40 GeV/ c .

2 data tables

AT SMALL -T, THE BINNING TENDS TO SMEAR OUT THE FORWARD DIP.


Photoproduction of Pions on Polarized Protons and Neutrons in the Second Resonance Region

Althoff, K.H. ; Gies, M. ; Herr, H. ; et al.
Nucl.Phys.B 131 (1977) 1-6, 1977.
Inspire Record 119995 DOI 10.17182/hepdata.35224

Measurements of the target asymmetry T = ( σ ↑ − σ ↓)/( σ ↑ + σ ↓) for the reactions γ p → π + n and γ n → π − p at a fixed photon energy of 850 MeV and pion c.m. angles between 70° and 150° are reported. The data are compared to the previously measured angular distribution at 700 MeV.

2 data tables

No description provided.

No description provided.


Photoproduction of Negative Pions on Polarized Neutrons in the Region of the Second Resonance

Althoff, K.H. ; Conrad, R. ; Gies, M. ; et al.
Nucl.Phys.B 116 (1976) 253-260, 1976.
Inspire Record 109397 DOI 10.17182/hepdata.35639

A polarized neutron target was used at the Bonn 2.5 GeV Synchrotron to measure the target asymmetry for the reaction γ n↑→ π − p at a fixed photon energy of 700 MeV and pion c.m. angles between 50° and 140°. The pions were detected in a large aperture magnetic spectrometer. The data show a structure which is quite different from the distribution previously measured for the reaction γ p↑→ π + n.

1 data table

No description provided.


Angular Distribution of the Target Asymmetry on Polarized Protons for the Reaction gamma p (Polarized) --> pi+ n at a Photon Energy of 700-MeV

Althoff, K.H. ; Conrad, R. ; Gies, M. ; et al.
Phys.Lett.B 63 (1976) 107-110, 1976.
Inspire Record 114330 DOI 10.17182/hepdata.27654

At the Bonn 2.5 GeV electron synchrotron the angular distribution of the target asymmetry T = (σ↑ − σ↓) (σ↑ + σ↓) for the reaction γp↑ → π + n was measured at a mean photon energy of 700 MeV and pion CM-angles from 50° to 155°. The combination of a 3 He-cryostat, polarizing the free protons in the target up to 65%, with a large acceptance magnet for pion detection led to statistical errors of the target asymmetry comparable with those of cross section measurements.

1 data table

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

No description provided.


Measurement of the Target Asymmetry for the Reaction gamma p --> pi+ n at Photon Energies Between 0.7-GeV and 2.2-GeV and a Pion CM Angle of 65-Degrees

Althoff, K.H. ; Conrad, R. ; Herr, H. ; et al.
Phys.Lett.B 59 (1975) 93-94, 1975.
Inspire Record 104242 DOI 10.17182/hepdata.5536

At the Bonn 2.5.GeV electron synchrotron the target asymmetry for the photoproduction of positive pions has been measured. Data were taken at photon energies between 0.7 and 2.2 GeV and a pion CM-angle of 65°.

2 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

No description provided.


Resonance Production in the Reactions pi+ d --> p(s) p pi+ pi- and pi+ d --> p(s) p pi+ pi- pi0 at 11.7-GeV/c

Kemp, D. ; Lotts, A.P. ; Scarrott, S.M. ; et al.
Nuovo Cim.A 27 (1975) 155-173, 1975.
Inspire Record 102951 DOI 10.17182/hepdata.37719

Results are presented for the reactions (1) π+n→pπ+π−, (2) π+n→pπ+π−π0, at an incident pion beam momentum of 11.7 GeV/c. Both reactions show considerable resonance production. Reaction (1) is dominated by ρ0 and f0 production and there is evidence for the variation of the ρ00 width with momentum transfer. Decay angular distributions are presented for the dipion system observed in reaction (1). Reaction (2) shows the production of both dipion and tripion resonances and there is evidence for the associated production of\(\mathcal{N}\)-resonances with the dipion resonances.

4 data tables

No description provided.

DN/DT PLOTTED. ALL RESONANCES ARE DEFINED JUST BY MASS CUTS.

RHO0 MASS REGION OF DIPION SYSTEM. NUMERICAL VALUES TAKEN FROM TABLE 6.1 OF THE THESIS BY D. KEMP (DURHAM 1974).

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Pi0 electroproduction at the delta(1236) resonance at a four-momentum transfer of q-squared = 0.3(gev/c)-squared

Baetzner, K. ; Beck, U. ; Becks, K.H. ; et al.
Nucl.Phys.B 76 (1974) 1-14, 1974.
Inspire Record 94609 DOI 10.17182/hepdata.32274

The reaction e − + p → e − + p + π 0 has been studied in the region of the Δ (1236) resonance at a four-momentum transfer of the virtual photon of 0.3 (GeV/ c ) 2 . Angles and momenta of the secondary electron and of the outgoing proton were measured in coincidence to obtain the angular dependence of the differential cross section. The angular distribution for s- and p-waves of the pion in the πN cm-system was fitted to the cross section for three W -bins around the maximum of the resonance. The contribution of the resonant multipoles M 1+ , E 1+ and S 1+ to the cross section as well as the contribution of the background amplitudes M 1− , E 0+ and S 0+ are given.

3 data tables

No description provided.

No description provided.

No description provided.


Electroproduction of eta-mesons at the s(11)(1535) resonance

Beck, U. ; Becks, K.H. ; Burkert, V. ; et al.
Phys.Lett.B 51 (1974) 103-105, 1974.
Inspire Record 95168 DOI 10.17182/hepdata.27938

The reaction e − + p → e − + p + η has been studied in the region of the S 11 (1535)-resonance by detecting the recoil proton in coincidence with the scattered electron. The reaction has been observed at three four-momentum transfers of the virtual photon: q 2 = 0.2, 0.28 and 0.4 (GeV/ c ). First results of the differential cross section measurements are given and compared with quark model calculations.

2 data tables

No description provided.

No description provided.