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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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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Strange-particle production from pi+ p interactions in the center-of-mass energy range 1820 to 2090 mev

Hanson, P. ; Kalmus, G.E. ; Louie, J. ;
Phys.Rev.D 4 (1971) 1296-1308, 1971.
Inspire Record 74874 DOI 10.17182/hepdata.23180

Data at nine π+ momenta are presented in the following three-body final states: Σ+K+π0, Σ+K0π+, Σ0K+π+, ΛK+π+, pK+K¯0. The data consist of cross sections, Dalitz plots, and angular distributions for the quasi-two-body final state Y*+(1385)K+. In the channel Y*+(1385)K+ the production and Y* decay distributions are compared with the predictions of Stodolsky and Sakurai.

3 data tables

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EVENTS ABOVE BACKGROUND - NO FIT.

DATA VALUES TAKEN FROM PDG2 CHEW 73B COMPILATION WHICH READ THEM FROM THE GRAPH AND CONVERTED TO MUB. BACKGROUND NOT SUBTRACTED.


TWO-BODY HYPERCHARGE EXCHANGE REACTIONS IN K- p AND pi+ p INTERACTIONS AT 10-GeV/c AND 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-London-Vienna collaboration Girtler, P. ; Otter, G. ; Bottcher, H. ; et al.
Nucl.Phys.B 159 (1979) 397, 1979.
Inspire Record 146303 DOI 10.17182/hepdata.34626

Cross-section values or upper limits are presented for twenty-five two-body hypercharge-exchange reactions in K − p and π + p interactions at 10 and 16 GeV/ c . The 16 GeV/ c results are compared with some predictions of line-reversal plus exchange-degenerate Regge poles, of SU(3) and of the additive quark model. Agreement is found in all cases.

1 data table

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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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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

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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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Confirmation of Exchange Degeneracy Predictions in the Line Reversed Reactions: $\pi^+ p \to K^+ Y^*(1385)$ and $K^- p \to \pi^- Y^*(1385)$ at 11.6-{GeV}/$c$

Ballam, Joseph ; Bouchez, J. ; Carroll, J.T. ; et al.
Phys.Rev.Lett. 41 (1978) 676, 1978.
Inspire Record 130550 DOI 10.17182/hepdata.20815

We have measured in a single experimental setup the differential cross sections and polarizations of the Y*(1385) produced in the two line-reversed reactions π+p→K+Y*(1385) (260 eV/μb) and K−p→π−Y*(1385) (180 eV/μb) at 11.5 GeV/c. We compare these results to Σ+ production in the same experiment. The data have been derived from a triggered bubble-chamber experiment using the SLAC Hybrid Facility. We find that both helicity-flip-dominated (Y*) and helicity-nonflip-dominated (Σ) processes are consistent with weak-exchange-degeneracy predictions.

5 data tables

Axis error includes +- 10/10 contribution.

Axis error includes +- 10/10 contribution.

Axis error includes +- 10/10 contribution.

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Strange Particle Production in Three and Four-Body Final States of 16-GeV/c pi+- p Reactions

The AACHEN-BERLIN-BONN-CERN-CRACOW collaboration Bosetti, P. ; Grassler, H. ; Otter, G. ; et al.
Nucl.Phys.B 128 (1977) 205-218, 1977.
Inspire Record 126061 DOI 10.17182/hepdata.35256

Three- and four-body final states with strange particles are studied in π + p and π − p interactions at 16 GeV/ c . We present cross sections and investigate their energy dependence. Production mechanism, resonance production and quantum number transfer are discussed. Strong Y ∗ (1385) production is found in the reaction π + p → Λ K + π + , while the corresponding π − p reaction is dominated by production of K ∗ (890). In the NK K π channels, the K and K are produced mainly at the same vertex, i.e. non-strangeness exchange ΔS = 0 is dominant (about 75% of the cases), whereas in the Λ K ππ channels, the Λ and K are more frequently produced at opposite vertices, i.e. | ΔS | = 1 exchange is important (about 60% of the cases). Results on the polarization of the lambdas produced in the π + p reactions are given.

1 data table

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