Measurement of the Spin Rotation Parameter, Beta, in the Reaction $\pi^+ p \to K^+ \Sigma^+$ at 1.60-{GeV}/$c$ and 1.88-{GeV}/$c$

Candlin, D.J. ; Lowe, D.C. ; Peach, K.J. ; et al.
Nucl.Phys.B 311 (1989) 613-629, 1989.
Inspire Record 263837 DOI 10.17182/hepdata.33220

Values of the spin-rotation parameter, β, are measured in the reaction π + p → K + Σ + at incident pion momenta of 1.69 and 1.88 GeV/ c .

2 data tables

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A PRECISION MEASUREMENT OF POLARIZATION PARAMETERS FOR THE PI+ + P ---> K+ + SIGMA+ REACTION AT 13 LABORATORY MOMENTA BETWEEN 1490-MEV/C AND 2069-MEV/C

Haba, J. ; Homma, T. ; Kawai, H. ; et al.
Nucl.Phys.B 299 (1988) 627-639, 1988.
Inspire Record 269585 DOI 10.17182/hepdata.33363

The polarization parameters for the π + +p→K + +∑ + reaction have been measured at 13 laboratory momenta between 1490 and 2069 MeV/ c in the angular range of −0.1⩽ cos θ K ∗ ⩽0.7 with higher statistics than previous experiments. In general, the present results agree well with the results at the Rutherford Appleton Laboratory. It is found, however, that there exist small but systematic differences which can be attributed to certain coefficients in Legendre expansions. The physical significance of these differences is discussed.

2 data tables

ALPHA0 is the decay asymmetry parameter (=0.980 +- 0.015 PDG tables).

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EXPERIMENTAL STUDY OF THE pi+ p ---> K+ SIGMA+ REACTION AT 12-GeV/c

The Dubna-Serpukhov-Baku-Bratislava-Gomel-Yerevan-Kiev-Kosice- Minsk-Samarkand-Tbilisi collaboration Bitsadze, G.S. ; Budagov, Yu.A. ; Vinogradov, V.B. ; et al.
Nucl.Phys.B 260 (1985) 497-509, 1985.
Inspire Record 207765 DOI 10.17182/hepdata.33721

The results of the study of the π + p→K + ∑ + (1) and π + p→K + ∑ + (1385) (2) reactions at 12 GeV/ c are presented. The differential cross sections d σ /d t in| t min |<| t |<0.8 (GeV/ c ) 2 momentum transfer range are measured. The ∑ + polarisation for | t |<0.5 (GeV/ c ) 2 for reaction (1) is defined. Binary reactions (1) and (2) were selected by analyzing the missing mass spectra for the forward emitted fast K + meson. The total cross sections in the studied momentum transfer range are 20.2±2.4 μ b and 7.3±1.1 μ b for the reactions (1) and (2) respectively. The experimental results are compared with the predictions of the Regge models which take into account rescattering and secondary singularities.

4 data tables

SYSTEMATIC ERRORS INCLUDED.

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Differential Cross-section and Polarization for $\pi^+ p \to K^+ \Sigma^+$ at 26 Momenta Between 1.282-{GeV}/$c$ and 2.473-{GeV}/$c$

Candlin, D.J. ; Lowe, D.C. ; Peach, K.J. ; et al.
Nucl.Phys.B 226 (1983) 1, 1983.
Inspire Record 183213 DOI 10.17182/hepdata.8242

Differential cross sections and polarisations in the reaction π + p→K + Σ + have been measured using the Rutherford Multiparticle Spectrometer at NIMROD. Data are presented at 26 momentum points at approximately 50 MeV/ c intervals in the range 1.282 to 2.473 GeV/ c with an order of magnitude more events than previous experiments. Legendre polynomial expansion coefficients have also been determined.

5 data tables

ERRORS HAVE SYSTEMATIC AND STATISTICAL ERRORS FOLDED IN QUADRATURE. TYPICAL STATISTICAL ERRORS ARE 2 PCT OR LESS.

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Study of the reactions pi+ p ---> k+ sigma+ and pi+ p ---> k+ y*+(1385) between 3.5 and 14 gev/c

Bashian, A. ; Finocchiaro, G. ; Good, M.L. ; et al.
Phys.Rev.D 4 (1971) 2667-2679, 1971.
Inspire Record 74763 DOI 10.17182/hepdata.23097

Measurements of the differential cross section for the reactions π+p→K+Σ+ and π+p→K+Y*+(1385) are reported at 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0, 6.0, 10.0, and 14.0 GeV/c. Polarization in π+p→K+Σ+ is also reported at 6.0, 10.0, and 14.0 GeV/c. At small |t|, the cross section for π+p→K+Σ+ is well described by an exponential Aebt with slopes in the range b≈8−10 (GeV/c)−2; for |t|>0.5 (GeV/c)2 this slope decreases considerably. The cross section for π+p→K+Y*+(1385) is well described for |t|>0.2 (GeV/c)2 by a single exponential of slope about half that for π+p→K+Σ+; there is no break near |t|>0.5 (GeV/c)2. We observe a dip in this cross section near t=0. The polarization in π+p→K+Σ+ is consistent with zero for |t|<0.4 (GeV/c)2 and becomes large and positive for larger |t|.

22 data tables

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Pi+- p elastic scattering and pi+ p ---> k+ sigma+ at 5.0 gev/c near -t=3.0(gev/c)-squared

Akerlof, C.W. ; Caldwell, P.K. ; Kalbaci, P. ; et al.
Phys.Rev.Lett. 27 (1971) 219-222, 1971.
Inspire Record 68949 DOI 10.17182/hepdata.21476

We have measured the reactions π±p→π±p and π+p→K+Σ+ at 5.0 GeV/c in the region 2.2<−t<3.5 (GeV/c)2. We find the minimum cross section of the dip at −t=2.8 (GeV/c)2 in π+p elastic scattering to be 0.16 ± 0.05 μb/GeV2. The π−p differential cross section exhibits similar structure, while the π+p→K+Σ+ channel shows a steady decline in cross section as |t| increases. The polarization of the Σ+ remains large and positive to at least −t=2.8 (GeV/c)2.

4 data tables

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Polarisation in the reaction pi+ p ---> k+ sigma+ at 1.11 gev/c

Bellamy, E.H. ; Anderson, J. ; Crawford, J.F. ; et al.
Phys.Lett.B 39 (1972) 299-302, 1972.
Inspire Record 75797 DOI 10.17182/hepdata.28308

The polarisation of the recoil sigma in the reaction π + p → K + Σ + has been measured at 12 production angles at a beam momentum of 1.11 GeV /c using counters and spark chambers. The new data are compared with existing phase shift solutions of π p → K Σ channels in the low energy region.

1 data table

THE ASYMMETRY PARAMETER, ALPHA, FOR SIGMA+ --> P PI0 IS CLOSE TO -1. THE LAST DATA VALUE IS DEDUCED FROM ALL THE EXPERIMENTAL EVENTS.


Study of the Reaction pi+ p --> K+ Sigma+ Between 1.721-GeV-1.954-GeV Center-Of-Mass Energy

Winik, M. ; Toaff, S. ; Revel, D. ; et al.
Nucl.Phys.B 128 (1977) 66-74, 1977.
Inspire Record 126060 DOI 10.17182/hepdata.35247

Cross-section, angular distribution and polarization measurements are presented at six incident π + energies for the reaction π + p → K + Σ + . Results at already studied energies are compatible with existing data and roughly agree with predictions of partial-waves analyses. However, new results around 1.920 GeV are in disagreement with such predictions, casting some doubt on the determination of decay branching ratios of the T = 3 2 isobars around this mass into K + Σ + .

8 data tables

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An Experimental Test of Exchange Degeneracy in the Reactions $\pi^+ p \to K^+ \Sigma^+$, $\pi^+ p \to K^+ \Sigma^+$ (1385) and Their Line Reversed Partners

Berglund, A. ; Buran, T. ; Carlson, P.J. ; et al.
Nucl.Phys.B 166 (1980) 25-61, 1980.
Inspire Record 143535 DOI 10.17182/hepdata.34526

A description is given of an experimental study of exchange degeneracy (EXD) in hypercharge-exchange reactions using the line-reversed partners π + p→K + Σ + (K − p→ π − Σ + ) and π + p→ K + Σ + (1385) (K − p→ π − Σ + (1385)) at incident momenta of 7.0 and 10.1 GeV/ c . Both pairs of reaction were measured in the same apparatus, with particular care being taken to minimize relative normalization errors. For the Σ production reactions we present high statistics measurements of the differential cross sections and polarizations from t ′=0 to large t . The general trends of the data agree with naive expectations from weak EXD. The cross-section difference in the extreme forward direction at the higher momentum is consistent with zero and there is a general reduction in the cross-section differences going from the lower to the higher momentum. The polarizations are approximately equal in magnitude and of opposite sign between the two reactions. On the other hand, the data do not agree with the detailed predictions of EXD. The slope for the positive reaction is systematically steeper in the forward region than for the negative reaction and there is a complex s and t dependence for the cross-section differences including a cross-over at t ⋍ −0.8( GeV /c) 2 . For the Σ(1385) production reactions, we present differential cross-section measurements in the forward region (| t |<0.3(GeV/ c ) 2 ). The cross-section differences are substantial and essentially constant over the s and t ranges studied.

2 data tables

THESE RESULTS WERE BRIEFLY REPORTED IN A. BERGLUND ET AL., PL 73B, 369 (1978), THE RECORD OF WHICH INCLUDES THE TABULATED DATA.

THE RESULTS AT 10.1 GEV WERE FIRST PUBLISHED IN A. BERGLUND ET AL., PL 60B, 117 (1975), THE RECORD OF WHICH INCLUDES THE TABULATED DATA.


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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