Pion production and elastic scattering in anti-proton-proton collisions at 6.94 bev/c

Ferbel, T. ; Johnson, J.A. ; Kraybill, H.L. ; et al.
Phys.Rev. 173 (1968) 1307-1314, 1968.
Inspire Record 55957 DOI 10.17182/hepdata.26499

We have studied nonstrange p¯−p interactions observed in 7000 pictures of the 80-in. Brookhaven National Laboratory hydrogen bubble chamber exposed to an antiproton beam with a momentum of 6.94 BeVc. The total cross section was measured to be 58.7±2.8 mb, and the elastic interaction cross section 14.2±1.2 mb. The elastic differential cross section for four-momentum transfers (−t)≤0.3 (BeVc)2 is well described by the exponential form dσeldt=(dσdt)t=0ebt, where b=13.1±1.1 (BeVc)−2. The single-pion production cross section is 4.0±0.9 mb. This channel proceeds 70% through resonance formation. N*(1238) isobar and anti-isobar formation dominates pion production in four- and six-pronged events; the double-isobar formation cross section in the final state pπ+p¯π− is 1.35±0.2 mb. Isobar production was observed to be consistent with the predictions of a dominant one-particle-exchange process. The pion-annihilation process, which has a cross section of 25±5 mb, shows substantial pion resonance formation.

1 data table

'1'. '2'.


Evidence for dominance of pomeron like exchange in p + p ---> n + n + pi at 19 gev/c

Boggild, H. ; Hansen, K. ; Johnstad, H. ; et al.
Phys.Lett.B 30 (1969) 369-372, 1969.
Inspire Record 56657 DOI 10.17182/hepdata.28910

The reactions pp → NN π are studied at 19 GeV/ c and analysed in terms of the amplitudes with the low mass N π system in isospin states 1 2 and 3 2 respectively. The I − 1 2 cross section is compared with the corresponding one in π p→ ππ N at 8 GeV/ c .

1 data table

Neutron-proton elastic scattering from 3 to 10 gev

Besliu, C. ; Besliu, T. ; Constantinescu, A. ; et al.
Nuovo Cim.A 59S10 (1969) 1-8, 1969.
Inspire Record 58947 DOI 10.17182/hepdata.37480

None

1 data table

'1'. '2'. '3'.


Negative Pion Production from Neutrons by Polarized gamma Rays

Nishikawa, T. ; Hiramatsu, S. ; Kimura, Y. ; et al.
Phys.Rev.Lett. 21 (1968) 1288-1291, 1968.
Inspire Record 944914 DOI 10.17182/hepdata.38534

The differential asymmetry ratio for the process γ+n→p+π− was measured at 90° in the center-of-mass system and for incident photon energies from 352 to 550 MeV. The observed asymmetries are larger than the values predicted from the theory by Berends, Donnachie, and Weaver. A smaller M1- amplitude gives better agreement between the experiment and the theory.

2 data tables

No description provided.

No description provided.


$\bar{p} -p$ Elastic Scattering at 6.9 GeV/c

Kitagaki, T. ; Takahashi, K. ; Tanaka, S. ; et al.
Phys.Rev.Lett. 21 (1968) 175-177, 1968.
Inspire Record 54434 DOI 10.17182/hepdata.198

The p¯−p elastic scattering at 6.9 GeV/c was studied by the analysis of antiproton film taken by the Brookhaven National Laboratory 80-in. hydrogen bubble chamber. The cross section of the elastic scattering was 14.7 ± 1.5 mb. The angular distribution showed a dip in the region of −t≈0.6 (GeV/c)2 and a secondary maximum at −t≈0.8 (GeV/c)2.

2 data tables

No description provided.

No description provided.


Nucleon Isobar Production in Proton-Proton Collisions between 3 and 7 GeVc

Ankenbrandt, C.M. ; Clark, A.R. ; Cork, Bruce ; et al.
Phys.Rev. 170 (1968) 1223-1236, 1968.
Inspire Record 54418 DOI 10.17182/hepdata.26506

A systematic study has been made of the reactions pp→pp and pp→pN* in the angular range from θlab=10∘ to θc.m.=90∘ at 3, 4, 5, 6, and 7 GeVc. An orthogonal dispersion magnetic spectrometer detected protons from interactions in hydrogen with momentum transfer (−t) in excess of 0.5 (GeV)2. Well-defined peaks in the missing-mass spectra occurred at average N* masses of 1240±6, 1508±2, and 1683±3 MeV with average full widths of 102±4, 92±3, and 110±4 MeV, respectively. Below 2400 MeV no other significant enhancements were found. The N* production cross sections dσdt near θc.m.=90∘ are in qualitative agreement with the predictions of the statistical model. For each isobar the differential cross section at fixed energy varies as exp(−vv0), where v≡[−tu(t+u)]; v0 varies systematically with energy and tends toward the same value (≈0.4 GeV2) for each isobar at the upper limit of our energy range.

1 data table

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pi+p Interactions at 900 MeV

Metzger, W.J. ; Forman, B. ; Melissinos, A.C. ; et al.
Phys.Rev. 164 (1967) 1680-1692, 1967.
Inspire Record 944947 DOI 10.17182/hepdata.26565

We report the results of the investigation of 18 500 frames of π+p interactions in the Brookhaven 20-in. bubble chamber at an incident energy of 900 MeV. It is found that single-pion production proceeds almost entirely through formation of the N33* isobar. The production mechanism of the N33* is analyzed in terms of its spin density matrix. Comparison is made with Stodolsky and Sakurai's ρ-exchange model and with the absorptive peripheral model.

1 data table

No description provided.


Large-Angle $\bar{p} p$ Elastic Scattering at 3.66 GeV/c

Katz, W.M. ; Forman, B. ; Ferbel, T. ;
Phys.Rev.Lett. 19 (1967) 265-267, 1967.
Inspire Record 52324 DOI 10.17182/hepdata.21752

The p¯p elastic-scattering differential cross section shows a minimum at t∼0.5 (GeV/c)2 and a secondary maximum at t∼0.9 (GeV/c)2. The total cross section for the annihilation process p¯+p→π−+π+ is 6.6±3.5 μb; the cross section for p¯+p→K−+K+ is <2.2 μb.

1 data table

Proton form factors from elastic electron-proton scattering

Janssens, T. ; Hofstadter, R. ; Hughes, E.B. ; et al.
Phys.Rev. 142 (1966) 922-931, 1966.
Inspire Record 49127 DOI 10.17182/hepdata.26698

Absolute measurements of the elastic electron-proton cross section have been made with a precision of about 4% for values of the square of the four-momentum transfer, q2, in the range 6.0 to 30.0 F−2 and for electron scattering angles in the range 45° to 145°. To within the experimental errors, it is found that the charge and magnetic form factors of the proton have a common dependence on q2 when normalized to unity at q2=0, and that an accurate representation of the behavior of the form factor and that of the cross sections themselves can be given in terms of a three-pole approximation to the dispersion theory of nucleon form factors.

27 data tables

Axis error includes +- 2./2. contribution (RANDOM ERROR).

Axis error includes +- 2./2. contribution (RANDOM ERROR).

Axis error includes +- 2./2. contribution (RANDOM ERROR).

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Observation of the Low-Energy Lambda-p Interaction

Melissinos, A.C. ; Reay, N.W. ; Reed, J.T. ; et al.
Phys.Rev.Lett. 14 (1965) 604-607, 1965.
Inspire Record 49710 DOI 10.17182/hepdata.21848

None

1 data table

No description provided.