SIGMA+ AND Y*+ (1385) PRODUCTION IN LINE REVERSED pi+ p AND K- p REACTIONS AT 7-GeV/c

Baker, P.A. ; Chima, J.S. ; Dornan, P.J. ; et al.
Nucl.Phys.B 166 (1980) 207-232, 1980.
Inspire Record 8326 DOI 10.17182/hepdata.34548

We have studied hypercharge exchange in two pairs of line-reversed reactions at 7 GeV/ c incident beam momentum in a triggered bubble chamber experiment at the SLAC Hybrid Facility. The experiment was carried out with the particular object of testing the predictions of exchange degeneracy using the same apparatus. We present differential and total cross sections for the reactions π + p → K + Σ + , K − p →π − Σ + and π + p → K + Y ∗+ (1385), K − p →π − Y ∗+ (1385) from a π + exposure of sensitivity 150 events/μb and a K − exposure of 100 events/μb. In each case we have measured the polarization of the final-state hyperon for | t |<1.0 (GeV/ c ) 2 by direct observation of its decay in the bubble chamber. We present results from an amplitude analysis of the Y ∗ (1385) reactions and find agreement with the predictions of the additive quark model. The Σ + polarization data are consistent with weak exchange degeneracy but the predicted equality of the differential cross section is not observed.

11 data tables

Axis error includes +- 10/10 contribution.

Axis error includes +- 10/10 contribution.

INCREASED STATISTICS OVER EARLIER RESULTS REPORTED IN P. A. BAKER ET AL., PRL 40, 678 (1978).

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Y* K AND Y* K* PRODUCTION IN pi+ p INTERACTIONS AT 10.3-GeV/c

Goddard, M.C. ; Key, A.W. ; Luste, G.J. ; et al.
Phys.Rev.D 19 (1979) 1350, 1979.
Inspire Record 7416 DOI 10.17182/hepdata.24321

The reactions π+p→Σ+(1385)K+ and π+p→Σ+(1385)K*+(890) are examined. The Σ+(1385)K+ differential cross section for −t′<0.5 GeV2 and spin density matrix elements agree with a Regge-pole model incorporating (nondegenerate) vector and tensor K* exchange with dominant M1 coupling. The Σ+(1385)K*+(890) density matrix elements are consistent with the quark-additivity predictions. A Y*+ at a mass of 1700 MeV is also observed in the Λπ+ mass distribution, produced opposite both K+ and K*+(890).

6 data tables

No description provided.

No description provided.

GOTTFRIED-JACKSON FRAME.

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PRODUCTION AND DECAY ANGULAR DISTRIBUTIONS OF THE Y* (1385) IN THE LINE REVERSED REACTIONS: pi+ p ---> K+ Y* (1385) AND K- p ---> pi- Y* (1385) AT 11.5-GeV/c

Cautis, C.V. ; Ballam, Joseph ; Bouchez, J. ; et al.
Nucl.Phys.B 156 (1979) 507-531, 1979.
Inspire Record 133382 DOI 10.17182/hepdata.34679

We have measured in a single experimental setup, the differential cross sections and decay angular distributions of the Y ∗ (1385) produced in the two line-reversed reactions: π + p → K + Y ∗+ (1385) (279 events/ω b ) and K − p → π − Y ∗+ (1385) (190 events/ωb) at 11.5 GeV/ c . The data have been derived from a triggered bubble-chamber experiment using the SLAC Hybrid Facility. We find the differential cross sections and Y ∗ polarizations for the two reactions to be in agreement with exchange-degeneracy predictions, if kinematic differences are taken into account. The Stodolsky-Sakurai and additive quark model predictions are in agreement with the main features of the decay angular distributions of the Y ∗ (1385), except for small violations at low momentum transfer, which can be associated with a finite helicity non-flip contribution in the forward direction.

6 data tables

Axis error includes +- 10/10 contribution.

THESE FINAL DIFFERENTIAL CROSS SECTIONS ARE INCLUDED IN THE RECORD OF J. BALLAM ET AL., PRL 41, 676 (1978).

TRANSVERSITY AMPLITUDES FOR SIG(1385P13)+ PRODUCTION. THE IMAGINARY PARTS OF T(11) AND T(-1-1) WERE ARBITRARILY FIXED AT ZERO.

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