Invariant single-particle cross sections for pion and proton production in π ± p interactions at 8 and 16 GeV/ c are presented in terms of integrated distributions as functions of x , reduced rapidity ζ and p ⊥ 2 , and also in terms of double differential cross sections E d 2 σ /(d x d p ⊥ 2 ) and d ζ d p ⊥ 2 ). A comparison of π ± and π − induced reactions is made and the energy dependence is discussed. It is shown that the single-particle structure function cannot be factorized in its dependece on transverse and longitudinal momentum. For the beam-unlike pion, there is an indication for factorizability in terms of rapidity and transverse momentum in a small central region.
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We have measured the reaction γ p → p π + π − in the DESY 1 m Streamer Chamber. The dominant ϱ o production is analyzed in terms of various models.
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FOR ALL EVENTS.
FOR ALL TWO PION EVENTS.
An analysis of the reaction π + n→ ω p in a 6.0 GeV/ c bubble chamber experiment is presented. The production differential cross section and spin density matrix elements are compared with Regge exchange models.
CORRECTED FOR BACKGROUND.
HELICITY FRAME. T-DEPENDENT BACKGROUND SUBTRACTED.
TRANSVERSITY FRAME. T-DEPENDENT BACKGROUND SUBTRACTED.
Measurements of proton-proton elastic scattering at angles around 6 mrad have been made at centre-of-mass energies of 23, 31, 45 and 53 GeV using the CERN Intersecting Storage Rings. The absolute scale of the cross-section was established by determination of the effective density of the colliding beans in their overlap region. Proton-proton total cross sections were deduced by extrapolation of the elastic differential cross-section to the forward direction and by application of the optical theorem. The results indicate that over the energy range studied the proton-proton total cross-section increases from about 39 to about 43 mb.
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NEW VALUES OF ELASTIC SLOPE USING APPARATUS DESCRIBED IN U. AMALDI ET AL., PL 43B, 231 (1973).
The differential cross section for the charge exchange p p → n n has been measured with high statistics at 7.76 GeV/ c and at 5.0 GeV/ c . The 7.76 GeV/ c data show a very narrow [ Δt ⪅ 0.01 (GeV/ c ) 2 ] forward peak superposed on a slow exponential fall-off.
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INTEGRATED CROSS SECTIONS FROM EXPONENTIAL FIT.
A bubble-chamber study is presented of a 10 events/μb experiment using K − mesons of 4.25 GeV/ c incident momentum. Differential and total cross sections are determined for 7 different reactions: K − p → K 0 n ( la ), → π 0 Λ ( lb ), → ηΛ ( lc ), → η′Λ ( ld ), → π − Σ ( le ), → π + Σ − ( lf ), K + Ξ − ( lg ) . The experimental characteristics in d σ /d t of each reaction are described: (la) shows a levelling off at t = 0 (GeV/ c ) 2 , a break at t = −0.6 (GeV/ c ) 2 and no backward events, (lb) d σ /d t has a smooth behaviour and a measurable backward component with an indication of a dip at u = −0.2 (GeV/ c ) 2 , (1c) d σ /d t shows a dip in the region between t ≈ −0.2 and −0.4 (GeV/ c ) 2 , (ld) d σ /d t has a smooth behaviour; neither this reaction nor the preceding one shows a clear evidence for backward events, (le) d σ /d t has a break at t = −0.5 (GeV/ c ) 2 ; there is a significant cross section in the backward region; (lf) and (lg) show mainly backward production. The polarization of the hyperon is measured in the reactions (lb), (lc), (ld) and (le) in the forward production peak. The statistics do not allow the detection of a definite structure in the polarization but the sign and magnitude are determined. An interpretation of the results is given in terms of a dual Regge model, including the effects of absorption as elaborated recently by several authors.
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The reaction K − p → X K − p has been measured at 25 and 40 GeV/ c at the Serpukhov accelerator using the CERN-IHEP boson spectrometer. At both energies we observe production of the resonances K ∗− (890) and K ∗− (1420) in the channels K ∗− → K 0 π − and K − π 0 ; the momentum dependence of their production cross sections is found to be σ[ K ∗− (890)] ∞ p inc −1.48±0.04 and σ [ K ∗− (1420)] ∞ p inc −0.8±0.2 .
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In an experiment with the CERN 2m deuterium bubble chamber the reaction K + d→K o pp (1) and the related reaction K + n→K o p (2) are studied at an incident momentum of 4.6 GeV/ c . The cross section for the latter reaction is found to be slightly larger than the cross section for the reaction K − p → K o n at the same energy. The corresponding differential cross sections agree within the rather large uncertainties. The forward amplitude for reaction (2) is predominantly real. Moreover, the total and forward differential charge exchange cross section values are compatible with those predicted on the basis of an SU (3) sum rule. A comparison of the K ± -charge exchange differential cross sections with the predictions of a Regge pole model is also presented.
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SMALL -T DEUTERIUM CORRECTION APPLIED USING MC GEE WAVE FUNCTION (PAPER ALSO GIVES UNCORRECTED AND HULTHEN CORRECTED DATA).
The reaction γp→; π + π − p in the energy range 4.1 to 6.2 GeV has been studied with a tagged photon beam incident on a liquid hydrogen target in the DESY one-meter streamer chamber. The reaction is analysed in terms of the longitudinal phase space (LPS) method. The one-pion-exchange model for Δ(1236) production and decay is examined. For the diffractive part of the LPS a dual model with pomeron exchange is investigated. In particular, the s -channel helicity conservation dual model of Dewey and Humpert describes the data well.
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CORRECTED FOR LOSSES AT SMALL T (UNLIKE VALUES OF 'REF 1'). BACKGROUND SUBTRACTION ERROR HAS BEEN ADDED QUADRATICALLY TO THE STATISTICAL ERROR.
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We have made a study of the coherent reaction K + d → K 0 π + d at 2 GeV/ c , using data obtained in the Lawrence Berkeley Laboratory 25 inch bubble chamber. The cross section for this reaction is 324 ± 25 μ b, after correction for invisible K 0 decays. This reaction is dominated primarily by vector exchange. We determine the parameters of the ω trajectory to be α ω = (0.33 ± 0.04) + t .
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SLOPE IS 9.4 +- 0.5 GEV**-2 FOR -T > 0.02 GEV**2 AND 10.4 +- 0.6 GEV**-2 FOR -TP > 0.
No description provided.