Spectra of hydrogen and helium ions emitted after stopped antiproton annihilation in nuclei have been measured with a Si-detector telescope. Targets of 12 C, 40 Ca, 63 Cu, 92 Mo, 98 Mo and 238 U were used. The 3 He and 4 He energy spectra can be fitted with the exponential function e − E / T . The parameter T is essentially independent of the target mass number A . A simple pickup model reproduces the 4 He/ 3 He ratios as a function of Z and N (target proton and neutron number). The proton spectra from the 238 U target indicate that some protons are also emitted by the fission fragments.
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Spectra of protons with momenta greater than 500 MeV/c following antiproton annihilation at rest in carbon and uranium nuclei have been measured. They are compared to recent results from other experiments and to predictions of an intranuclear cascade model. Evidence is presented for a substantialB>0 component in the annihilation process, and an estimate of the magnitude of that component is made.
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In collisions of 40-GeV/c antiprotons with D, Li, C, S, Cu, and Pb nuclei, mean multiplicities of various secondary particles are investigated as functions of the mass number A. The mass-number dependence of the mean multiplicities of positively charged particles suggests that the effect of intranuclear cascades is strong for the emission of Λ hyperons, but that it is relatively weak for the emission of either K 0 or \(\bar \Lambda \). Also measured are the yields of various neutral strange particles with respect to those of charged secondaries.
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Energy spectra of protons, deuterons and tritons from stopped-antiproton annihilation in Li, Si, Ca, Ni, Ge, Mo, Ho, Yb, Pb and Th have been measured with a Ge detector telescope. The shapes of these and of previously obtained spectra and the corresponding yields were analysed and compared with statistical calculations including intranuclear cascade, coalescence, pre-equilibrium processes, evaporation, multifragmentation and Fermi break-up. The relative importance and the A -dependence of the various processes are elucidated.
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The inclusive cross sections of backward proton production in π − ( K − , p ) -Be, Al, Cu, Pb interactions at 40 GeV/ c are presented. Protons have been detected in the angular range 150°–165° and kinetic energy region 0.1–0.3 GeV. The invariant cross-section ratios for various beam particles are independent of the values of kinetic energy and of the nuclear target type: 〈ƒ K − /ƒ π − 〉= 0.87 ± 0.03 stat ± 0.03 syst , 〈ƒ p /ƒ π − 〉 = 1.82 ± 0.10 stat ± 0.05 syst . The A -dependence of the cross-section slope parameter for A ⩾27 is less than ∼2%.
CYCLE N1.
CYCLE N1.
CYCLE N1.
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RUN 1.
RUN 1.
RUN 1.
Energy spectra of protons, deuterons and tritons from the annihilation of antiprotons stopped in 12 C, 40 Ca, 63 Cu, 92,98 Mo and 238 U have been measured with a Ge-detector telescope. Parameters related to the shape of the spectra were calculated and their dependence on target and ejectile mass number was determined. Yields per p̄ of directly emitted protons, deuterons and tritons and of evaporated protons were estimated.
THE PROTON SPECTRA WERE FITTED WITH THE EXPRESSION N(E)=N1*EXP( -SLOPE(Q=1)*E)+N2*EXP(-SLOPE(Q=2)*E).
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
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NUCLEUS IS C6J.
NUCLEUS IS C6J.
NUCLEUS IS C6J.
We have studied (p̄, p) reactions on 12 C , 63 Cu, and 209 Bi to search for possible nuclear states formed ny antiprotons and nuclei. The experiments used the 180 MeV antiproton beam from LEAR, and the high-resolution magnetic spectrometer, SPES II, to detect the outgoing protons. No evidence of antiproton-nucleus states was found. The gross features of the proton spectra are reasonably well described by intranuclear cascade model calculations, which consider proton emission following antiproton annihilations in the target nucleus.
Parameters resulting from the best fits to the proton spectra with the expression D2(SIG)/D(OMEGA)/D(E) = CONST*SQRT(E)*EXP(-E/SLOPE).
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