Polarization Measurement of the $\Sigma^+$ Produced in the Line Reversed Reactions $\pi^+ p \to K^+ \Sigma^+$ and $K^- p \to \pi^- \Sigma^+$ at 7-{GeV}/$c$ and 11.6-{GeV}/$c$

Baker, P.A. ; Chima, J.S. ; Dornan, P.J. ; et al.
Phys.Rev.Lett. 40 (1978) 678, 1978.
Inspire Record 129108 DOI 10.17182/hepdata.20914

The polarization of the Σ+ has been measured for the line-reversed reactions π+p→K+Σ+ and K−p→π−Σ+ at 7 and 11.6 GeV/c using the SLAC Hybrid Facility. Since the Σ+ decay is observed in the bubble chamber, the trigger of the flash lamps on a fast K+(π−) did not bias the polarization measurements. We find that the Σ+ polarizations from the two reactions have opposite signs but similar magnitudes and are in much better agreement with the predictions of weak exchange degeneracy than previous lower-energy comparisons.

1 data table

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AN EXPERIMENTAL TEST OF EXCHANGE DEGENERACY IN THE HYPERCHARGE EXCHANGE REACTIONS PI+ P ---> K+ SIGMA+ AND K- P ---> PI- SIGMA+

Berglund, A. ; Buran, T. ; Carlson, P.J. ; et al.
Phys.Lett.B 73 (1978) 369-374, 1978.
Inspire Record 134098 DOI 10.17182/hepdata.27470

For the first time, the line reversed reactions π + p→K + Σ + and K − p→ π − Σ + have been studied in the same apparatus. We present the differential cross sections and polarizations over a large t range and at two momenta, 7.0 and 10.1 GeV/ c . The differential cross sections as a function of t are shown for the first time to cross over. Going from the lower to the higher momentum, the differences in cross section between the two reactions diminish at low | t | by about a factor 2. We find large polarizations of opposite sign for the two reactions. The momentum dependence, presented in the form of α eff ( t ) for the t range 0 to −2 (GeV/ c ) 2 , is compared with the expectations from the K ∗ −K ∗∗ trajectory.

10 data tables

-TMIN = 0.0100 GEV**2.

-TMIN = -0.0087 GEV**2.

-TMIN = 0.0067 GEV**2.

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New Limits for the Exotic Exchange Reaction pi- p --> K+ Sigma- at 5-GeV and 8-GeV

Dekkers, D. ; Guillaud, J.P. ; Lepeltier, V. ; et al.
Nucl.Phys.B 131 (1977) 72-79, 1977.
Inspire Record 126514 DOI 10.17182/hepdata.35221

Measurement of the exotic exchange reaction π − p → K + Σ − has been performed at 5 and 8 GeV, in the −0.015 to −0.13 and −0.009 to −0.15 (GeV/ c ) 2 range of t repectively. We give the value near t = 0 of the differential cross section at 5 GeV, 21 −21 +76 nb/(GeV/ c ) 2 , and an upper limit (< 37 nb/GeV/ c ) 2 ) at 8 GeV. As a check the measured differential cross section is given at both energies for the reaction π + p → K + Σ + in the same range of t ★★ ★★ Results presented here were included in the thesis of Doctorat d′Etat by M.N. Minard, Orsay, France, 1976. .

2 data tables

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