A Study of Proton-Induced Pion Production on C at Intermediate Energies via Recoil Detection (original) (raw)
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The European Physical Journal C, 2013
Recent data on proton and pion production in p + C interactions from the CERN PS and SPS accelerators are used in conjunction with other available data sets to perform a comprehensive survey of backward hadronic cross sections. This survey covers the complete backward hemisphere in the range of lab angles from 10 to 180 degrees, from 0.2 to 1.4 GeV/c in lab momentum and from 1 to 400 GeV/c in projectile momentum. Using the constraints of continuity and smoothness of the angular, momentum and energy dependences a consistent description of the inclusive cross sections is established which allows the control of the internal consistency of the nineteen available data sets.
Multinucleon contributions to the 12C(π+, pp) reaction at 100 and 165 MeV incident pion energies
Nuclear Physics A, 1997
Differential and total cross sections for ~-+ absorption on ~2C are presented at incident pion energies of 100 and 165 MeV. This is the first time that this reaction has been measured with a combination of good energy and angle information over an extensive region of phase space. Results are compared to extensive Monte Carlo simulations in order to investigate the role of two-and multinucleon absorption processes in this nucleus. Signatures of ISI and FSI in the pion absorption process are also investigated, in order to explain the complex reaction mechanism implied by the data. @ 1997 Elsevier Science B.V.
Inclusive production of π 0 mesons in the reaction 12 C + 12 C → π 0 + x at 4.5 GeV/c per nucleon
Soviet Journal of Nuclear Physics (English Translation), 1991
The cross sections for inclusive neutral-pion production in the reactions d + C → π 0 + x and d + Cu → π 0 + x at a momentum of 4.5 GeV/c per nucleon were measured over the kinematical region specified by the inequalities θ π ≤ 16 • and E π ≥ 2 GeV (in the laboratory frame). From the ratio of the cross sections for neutral-pion generation on carbon and copper nuclei, the exponent n in the parametrization Ed 3 σ/d 3 p ∼ A n T is obtained as a function of the cumulative number X in the range 0.6 ≤ X ≤ 1.8 and as a function of the square of the transverse momentum in the range 0.04 ≤ P 2 t ≤ 0.40 (GeV/c) 2. The probabilities of the formation of six-quark configurations in the D, 4 He, and 12 C nuclei are estimated. The double-differential cross section for the reaction d + C → π 0 + x is determined for the first time by using a data sample containing more than 40 000 neutral pions.
Measurement of the production cross-sections of π ± in p–C and π ± –C interactions at 12 GeV/c
Astroparticle Physics, 2008
The results of the measurements of the double-differential production cross-sections of pions, d2σπ/dpdΩ, in p–C and π±π±–C interactions using the forward spectrometer of the HARP experiment are presented. The incident particles are 12 GeV/c protons and charged pions directed onto a carbon target with a thickness of 5% of a nuclear interaction length. For p–C interactions the analysis is performed using 100,035 reconstructed secondary tracks, while the corresponding numbers of tracks for π-π-–C and π+π+–C analyses are 106,534 and 10,122, respectively. Cross-section results are presented in the kinematic range 0.5GeV/c⩽pπ<8GeV/c and 30mrad⩽θπ<240mrad in the laboratory frame. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range.
Positive Pion Production in Proton-Nucleus Collision
Progress of Theoretical Physics, 1977
Positive pion production process on 12 C by 185 MeV proton is studied within the framework of DWBA by adopting the Kisslinger-type optical potential for the final state interaction. The qualitative features of this reaction are explained if the off-shell part of the optical potential is modified by introducing the vertex function. This modification scarcely affects elastic pion-nucleus scattering. § 1. Introduction Pion production process (p, n+) on nuclei is one of the interesting phenomena m pion-nucleus interactions.v~sl As a neutron is transferred into the target nucleus, this reaction is analogous to the ordinary nuclear reactions, such as (d, p) and (n, r). Since the measurements of the cross sections of 12 C (p, n+) 13 C by the U ppsala group by the use of the 185 MeV proton beams,7)~lol this reaction has been paid much attention theoretically.11)~,sl Most of the theoretical work was based upon the DWBA theory by adopting the Kisslinger-type optical potential for describing the emitted pion! 1 l, 25 l and the conventional static pion-nucleon interaction for the vertex of pion production. The calculated values of the cross section were shown to be larger than the experimental values by one or two orders of magnitude.m. 18 l In this connection, Miller found the parameter set of the Kisslinger-type optical potential which explains elastic scattering and the (P, n+) reaction on 12 C. 19 l His parameters are, however, quite different from those commonly used in elastic scattering on 12 C." 6 l~zsl Recently Miller and Phatak 20 l have calculated the 12 C (P, ni) 13 C reaction cross section, using the separable pion-nucleon potential proposed by Landau et al." 9 l~sJJ Although the results are in agreement with the experimental data, the range parameters adopted for the nuclear form factor are somewhat too large. Besides, the vertex of pion emission was also investigated by Lee and Pittel, 22 l and by Noble. 23 l From the kinematical consideration the above complicated situations can be ascribed to the off-shell behavior of pion-nucleon interaction, to which elastic pionnucleus scattering is rather insensitive: If we switch off the initial and final state interactions in the above reaction, the momentum of the transferred neutron is 460~660 MeV/ c, \vhich is far above the Fermi momentum. Therefore, the cross section for this reaction is expected to be very small. However, if we take into
Nuclear Physics A, 1987
The paper presents an in-depth study on the forward and backward multiplicity correlations in case of pions and protons (from the target) based on the experimental data on 12C-emulsion interaction at 4.5 GeV/c per nucleon. The cumulative distribution of their emission angles in the backward hemisphere is presented. The asymmetry parameter (A) and the forward-backward ratio (F/B) as a function of the number of heavy particles (nh) is also shown. The results reveal many interesting characteristics regarding the backward particle production.
Kinematically complete measurement of the (π±,π±p) reaction onC12at 220 MeV
Physical Review C, 1984
The "C(n.-, m-+ p) reactions were studied at T = 220 MeV. The final particles were detected both separately and in coincidence and their momenta were measured. Calculation of the excitation energy of the residual nucleus allowed clear separation of events where an outer proton was removed. The data provide detailed evidence confirming the quasielastic picture of pion knockout reactions. Evidence for this derives from the agreement between the peak energies found in the coincidence spectra and those found in inclusive spectra, from analysis of angular distributions, and from the location of peaks found in missing mass spectra. The coincidence cross section is found to account for about half of the (m. +, n. +') reaction, and about half of this in turn corresponds to quasifree knockout of the outer shell protons. Secondary processes in the (n. , m. p) reaction are found to play a much more important role than in the (n.+, m. +p) reaction.
European Physical Journal C, 2008
A measurement of the double-differential π± production cross-section in proton–carbon, proton–copper and proton–tin collisions in the range of pion momentum 100 MeV/c≤pc and angle 0.35 rad≤θHARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c).
Measurements of cross sections and charged pion spectra in proton-carbon interactions at 31 GeV/c
Physical Review C, 2011
Interaction cross sections and charged pion spectra in p+ C interactions at 31 GeV/c were measured with the large-acceptance NA61/SHINE spectrometer at the CERN SPS. These data are required to improve predictions of the neutrino flux for the T2K long-baseline neutrino oscillation experiment in Japan. A set of data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of a nuclear interaction length was used for the analysis. The measured p+ C inelastic and production cross sections are 257.2±1.9±8.9 and 229.3±1.9±9.0 mb, respectively. Inclusive production cross sections for negatively and positively charged pions are presented as functions of laboratory momentum in ten intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models.