An investigation of the production of neutron-rich isotopes from the fragmentation of Si28 projectiles at plab=14.6 GeV/c per nucleon was performed using the BNL-AGS-E814 spectrometer. We have measured the inclusive production cross sections of neutron-rich fragments (6He, He8, Li8, Li9, Be10, Be11, and B13). We have also measured the transverse momentum distributions for He6 and Li9, and the forward and transverse energy distributions associated with He6 production. The momentum distributions were analyzed in the context of the Goldhaber model. The question of whether the fragments are produced in the decay of the projectile following its electromagnetic excitation was also investigated.
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The differential cross section of the charge-exchange reaction p p → n n has been measured at the CERN Low Energy Antiproton Ring (LEAR) at seven p momenta in the range 546–1287 MeV/ c . A pentanol polarized target has been used and the neutron and the antineutron have been detected in coincidence. The data cover most of the angular range.
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We have observed the ηπ + π − and ηπ 0 π 0 decay modes of the E meson in p p annihilation at rest into π + π − π 0 π 0 η . The mass and width of the E meson are 1409 ± 3 and 86 ± 10 MeV. The production and decay branching ratio is B( p p → Eππ)B(E → ηππ) = (3.3 ± 1.0) × 10 −3 . With a spin-parity analysis we determine that J P = 0 − . The observation of the ηπ 0 π 0 decay mode establishes that E is isoscalar ( C = +1). We find that E decays to η ( ππ ) s (where ( ππ ) s is an S-wave dipion) and πa 0 (980)(→ πη ) with a relative branching ratio of (78 ± 16) %. Using the K K π production and decay branching ratio measured earlier we determine that B[E → K K π] B[E → ηππ] = 0.61 ± 0.19 . A comparison with observations in radiative J Ψ decays suggests that E and ι η (1416) are identical.
Unobserved channels (E --> ETA 2PI0)2PI0 and (E --> ETA PI+ PI-)PI+PI- was taken into account.
In this letter the distribution of slow target associated particles emitted in Au + Emulsion interactions at 11.6 A GeV/ c is studied. The three models RQMD, FRITIOF and VENUS are used for comparisons and especially their treatment of rescattering is investigated.
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PROJECTILE ASSOCIATED HE-FRAGMENTS.
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We report a study of single photon production in e + e − collisions at s =58 GeV with the TOPAZ detector at TRISTAN. From data corresponding to an integrated luminosity of 213 pb −1 , 5 single photon candidates remained after event selection, which can be compared with the expected 3.1 ν ν γ and 2.8 background events. These results exclude the selectron mass below 47.2 GeV at the 90% confidence level, if e ̃ L and e ̃ R are mass-degenerate and the photino is massless. When combined with results from other experiments, this limit improves to 75.0 GeV.
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The depolarization parameter Donon of the p dash p → n dash n charge exchange reaction has been measured for the first time at the CERN Low Energy Antiproton Ring (LEAR) at two antiproton momenta, 546 and 875 MeV/ c . The transverse polarization of the recoil neutron was analyzed using a large-acceptance neutron polarimeter made up of two parallel plastic scintillator planes. D 0 n 0 n is usually less than 0.35 which suggests that the spin-spin amplitudes dominate in the scattering matrix. Results are compared with the predictions of various N dash N potential models. The agreement is in general satisfactory.
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We have conducted a search for bound states of a negative pion and a number of neutrons (pineuts) using the E814 spectrometer. A beam of Si28 at a momentum of 14.6A GeV/c was used to bombard targets of Al, Cu, Sn, and Pb. We describe our experimental technique, present measured upper limits for pineut production, and discuss the significance of our results.
AUTHORS NAMED CHARGED- BY PINEUT. Here ALL means the total number of interactions.
The polarization transfer κ 0 and the tensor analyzing power T 20 for the 1 H d p)d reaction have been measured up to an internal momentum of k = 0.58 GeV/c. Comparison of the same observables obtained in recent studies for 1 H d p)d reaction, as a function of k , show different behavior. However the data from these two reactions are almost identical when compared in T 20 versus κ 0 correlation plots. We discuss similarities and differences observed in the two reactions.
The authors use the Infinite Momentum Frame variable K= M( proton) * sqrt(1/(4*a*(1-a)) - 1), where a = (E(proton)+P_long(proton))/(E(deut)+P(deut)).
The annihilation p p → Φγ has been investigated with the Crystal Barrel detector at LEAR for antiprotons stopped in liquid hydrogen. The observed branching ratio BR ( p p → Φγ = (1.7 ± 0.4) · 10 −5 is almost two orders of magnitude higher than expected from the OZI-rule. As a by-product, the branching ratios BR ( p p → K L K S ) = (9.0 ± 0.6) · 10 −4 and BR ( p p → Φπ 0 ) = (5.5 ± 0.7) · 10 −4 have been measured.
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