Neutron-proton interactions in the energy range (290 ÷ 970) MeV
Tóm tắt
A study of inelastic n-p interactions has been made using the Birmingham 1 GeV synchrotron and a 9 in. diameter liquid hydrogen bubble chamber. 1840 three-pronged events initiated by neutrons in the energy range (290 ÷ 970) MeV have been analysed, the possible reactions being: n + p → p + p + π−; n + p → n + p + π0, π0 → e+ + e- + γ, and n + p → n + p + π+ + π−. The ratio found for the integrated cross-sections σ(n + p → n + p + π0) /σ (n + p → p + p + ρ-) = 2.67 ± 0.43 is shown to resolve a long-standing conflict with charge independence. The energy-dependence of the n + p → p + p + π− cross-section has been inferred from the expected shape of the incident neutron spectrum with the aid of earlier cross-section measurements in the energy range. The laboratory kinetic energy distributions and centre-of-mass angular distributions for protons from ppπ- events suggest that the peripheral mechanism of interaction is important at lower energies and to a greater extent than indicated by the one-pion-exchange model. However the Treiman-Yang test for this model is satisfied for events involving small momentum transfer and (3, 3) isobar production. The cross-section for the reaction n + p → n + p + π+ + π- increases more quickly above threshold than required by the statistical model of Cerulus and Hagedorn, and much more so than required by one-pion-exchange processes. Comparison with p-p scattering results, in which double-pion production is far smaller, emphasizes the importance of theT=0 channel.
Tài liệu tham khảo
D. V. Bugg, A. J. Oxley, J. A. Zoll, J. G. Rushbrooke, V. E. Barnes, J. B. Kinson, W. P. Dodd, G. A. Doran andL. Riddiford:Phys. Rev.,133 B, 1017 (1964).
W. J. Fickinger, E. Pickup, D. K. Robinson andE. O. Salant:Phys. Rev.,125, 2082 (1962).
G. A. Smith, H. Courant, E. C. Fowler, H. Kraybill, J. Sandweiss andH. Taft:Phys. Rev.,123, 2160 (1961);E. L. Hart, R. I. Louttit, D. Luers, T. W. Morris, W. J. Willis andS. S. Yamamoto:Phys. Rev.,126, 747 (1962).
A. P. Batson, B. B. Culwick, H. B. Klepp andL. Riddiford:Proc. Roy. Soc. (London), A251, 233 (1959).
W. A. Wallenmeyer:Phys. Rev.,105, 1058 (1957).
W. B. Fowler, R. P. Shutt, A. M. Thorndike andW. L. Whittemore:Phys. Rev.,95, 1026 (1954).
F. N. Holmquist: UCRL 8559 (1958).
G. B. Yodh:Phys. Rev.,98, 1331 (1955);
V. Dzhelepov, K. Oganesyan andV. Fliagin:Soviet Phys. JETP,2, 757 (1956);
Y. M. Kazarinov, Y. N. Simonov:Soviet Phys., JETP,8, 56 (1959);
A. F. Dunaitsev andY. D. Prokoshkin:Soviet Phys. JETP,11, 540 (1960), where a comprehensive review is given of single-pion production, including an extensive list of references.
J. G. Rushbrooke:Ph. D. Thesis, University of Cambridge (1962).
M. Jobes:Ph. D. Thesis, University of Birmingham (1964).
V. Kiselev, K. Oganesyan, R. Poze andV. Fliagin:Soviet Phys. JETP,8, 564 (1958). Further details of neutron spectra from proton-nucleus collisions may be found inB. Nelson, G. Guernsey andG. Mott:Phys. Rev.,88, 1 (1952);J. de Pangher:Phys. Rev.,99, 1447 (1955);A. J. Hartzler andR. Siegel:Phys. Rev.,95, 181, 591 (1954).
Y. D. Prokoshkin andA. A. Tyapkin:Soviet Phys. JETP,5, 618 (1957);
B. S. Neganov andO. Savchenko:Soviet Phys. JETP,5, 1033 (1957);
A. Mesh-kowskii, I. Shalamov andV. Shebanov:Soviet Phys. JETP,8, 46 (1959);
T. H. Fields, J. C. Fox, J. A. Kane, R. A. Stallwood andR. B. Sutton:Phys. Rev.,109, 1713, 1716 (1958);
G. D. Mead: UCRL 10187 (1962).
S. Mandelstam:Proe. Roy. Soc. (London), A244, 491 (1958).
A. H. Rosenfeld:Phys. Rev.,96, 139 (1954).
R. R. Larsen: UCRL 9292 (1960).
H. Palevsky, J. A. Moore, R. L. Steavens, H. R. Muether, R. J. Sutter, R. E. Chrien, A. P. Jain andK. Otnes:Phys. Rev. Lett.,9, 509 (1962).
W. P. Dodd:Ph. D. Thesis, University of Birmingham (1963).
S. J. Lindenbaum andK. M. Sternheimer:Phys. Rev.,105, 1874 (1957);
R. M. Sternheimer andS. J. Lindenbaum:Phys. Rev.,123, 333 (1961).
F. F. Chen, C. P. Leavitt andA. M. Shapiro:Phys. Rev.,103, 211 (1956).
F. Cerulus andR. Hagedorn:Nuovo Cimento,9, 646 (1958).
R. Hagedorn:Nuovo Cimento,25, 1017 (1963).
D. W. Joseph:Nuovo Cimento,16, 997 (1960).
E. Ferrari andF. Selleri:Suppl. Nuovo Cimento,24, 453 (1962).
E. Ferrari andF. Selleri:Nuovo Cimento,27, 1450 (1963).
V. E. Barnes, D. V. Bugg, W. P. Dodd, J. B. Kinson andL. Riddiford:Phys. Rev. Lett.,7, 288 (1961).
S. B. Treiman andC. N. Yang:Phys. Rev. Lett,8, 140 (1962).
E. Ferrari:Phys. Lett.,2, 66 (1962).
G. Morpurgo:Nuovo Cimento,4, 1222 (1956);5, 1787 (1957).
P. Eberhard andM. L. Good:Phys. Rev.,120, 1442 (1960).
M. Peshkin:Phys. Rev.,123, 637 (1961).
R. K. Adair:Phys. Rev.,100, 1540 (1955).
M. Derrick, J. C. Fetkovich, T. H. Fields andJ. Deahl:Phys. Rev.,120, 1022 (1960).
N. P. Samios:Phys. Rev.,121, 275 (1961).
N. P. Samios, R. Plano, A. Prodell, M. Schwarz andJ. Steinberger:Phys. Rev.,126, 1884 (1962).
N. M. Kroll andW. Wada:Phys. Rev.,98, 1355 (1955).
E. Ferrari: CERN Int. Rep. 6078/TH 328 (1963).
C. Baltay,et al.: Interactions of High-Energy Anti-protons in Hydrogen, paper submitted to theStanford Nucleon Structure Meeting (June 24–27, 1963).