Monroe S. Rabin

Analysis of the observed anomaly in ππ s-wave scattering near KK̄ threshold

Abstract The character of the ππ s-wave scattering amplitude near 980 MeV is determined from the reactions π + p→‡ ++ π + π − and ‡ ++ K + K − at 7GeV/c.

Observation of an anomally in the π+π− system at 980 MeV

Abstract An anomaly at 980 MeV is seen in both the mass distribution and angular distribution of the π + π − system produced in the reaction π + p → Δ ++ π + π − at 7 GeV/ c . Experimental results for the related final states Δ ++ K + K − , Δ ++ π + π − π + π − and Δ ++ π + π − (neutrals) are presented.

A Polarized Photon Beam for the SLAC 82-Inch Hydrogen Bubble Chamber

Compton scattering of ruby laser light from a high energy electron beam at SLAC has been employed to produce a highly polarized, partially monochromatic photon beam of energy up to 7 GeV.

Energy dependence of inclusive distributions in pion-induced reactions☆

Abstract We present data on the inclusive distributions π + p → π ± + anything and π − p → π − + anything at momenta from 3.7 to 18.5 GeV/ c . Distributions are presented in the laboratory, center-of-mass and projectile systems, and the approach to scaling is discussed.

A2 mass spectrum in 7-GeV/c π+p interactions

Abstract The A 2 mass spectrum is studied in the reaction π + p→A 2 + p atZZ 7 GeV/ c in a hydrogen bubble chamber in order to investigate previously reported structure. We report on 1400 A 2 events with mass resolutions of 3.8, 6.7 and 9.2 MeV in the K + K 0 , 3π and ηπ + channels.

Experimental spectra for 12 GeV/c K+p → pK+φ and pK+ω

We present experimental distributions for the reactions K+p → pK+φ, φ → K−K+ and K+p → pK+ω, ω → π−π+π0 at 12 GeV/c. The data were obtained from a 35 events/μb exposure of the SLAC 82-inch HBC. The cross sections for these reactions are (11 ± 1) μb and (47 ± 3) μb. We observe Kφ, Kω, and pω low-mass enhancements with no evidence for narrow structure. The momentum-transfer and angular-decay spectra of these systems are presented.

Branching ratios of the A2+ meson observed in 7 GeV/c π+p interactions☆

Abstract The observed branching fractions of the A 2 + produced in the reaction π + p→A 2 + p at 7 GeV/ c and decaying to ϱπ, ηπ, K K and η′π are presented. The data show no convincing evidence for the decay A 2 + → η ′ π + , the branching fraction being less than 3%. For the other decay modes the values obtained for ϱπ, ηπ and K K are 0.744 ± 0.029, 0.183 ± 0.026 and 0.072 ± 0.012 respectively.

Study ofγp→pωwith Linearly Polarized Photons at 2.8 and 4.7 GeV

1. Vertical scales for the density matrix elements p:O, Re p;O and piwl * are incorrectly labeled in Fig. 4. Change 0.4 to 0.2 and -0.4 to -0.2. Other density matrix elements and Pa are correctly labeled. 2. There are two typographical errors in Table IV: In IV-a (2.8 GeV Gottfried-Jackson system) for 0.06 5 It I I 0.15 GeV2, the value of 0 Re PlO is given as -0.14 f 0.04; it should be +O. 14 f 0.04. In IV-e (4.7 GeV helicity system) for 0.014 5 It I ,< 0.06 the value of pi-l should be -0.04 f 0.12; it is shown correctly in Fig. 4.

The ρO − ω interference parameters in diffractive photoproduction of vector mesons on hydrogen

We have examined the reaction γp → π+π−p for evidence of ϱo − ω interference. Assuming the ratio of the ϱo and ω-photoproduction amplitudes to be |Aϱ/Aω|2 = 7.1 ± 0.7, we find that the Re(δeiβ) = 2.3 ± 0.9 MeV and Im (δeiβ) = −0.4 ± 0.9 MeV, where δ(≈ 2.3 MeV) is the mass mixing parameter and β(≈ −9o) is the relative phase of the ϱo −ω amplitudes. Our result, obtained using a hydrogen bubble chamber, agrees with the high-statistics Daresbury result using photoproduction on carbon.

The design for a nonintercepting photon-beam monitor☆

Abstract We describe the design of a combination collimator-monitor used with the SLAC Compton-scattered photon beam facility. The beam is collimated to a half angle of 10 −5 rad and the monitor is sensitive to changes in beam steering of 10 −6 rad.