Results are presented on an analysis of the reaction K + p → K ∗+ (890) p at 16 GeV/ c and compared with data at lower incident momenta and with corresponding results for the reaction K − p → K ∗− (890) p. It is found for both reactions that the energy dependence of the cross section exhibits a simple ( p − n lab behaviour.
BREIT-WIGNER RESONANCE FITS WITH BACKGROUND.
The transverse momentum distribution at 90° of pions, protons and antiprotons have been measured at the CERN intersecting storage rings for C.M. energies between 23.2 and 52.7 GeV. In this energy range, the pion and proton distributions are almost energy independent. The antiproton production rises by a factor of two between 23.2 and 52.7 GeV.
The invariant cross section was fitted by CONST*EXP(-SLOPE*PT).
The invariant cross section was fitted by CONST*EXP(-SLOPE(C=1)*PT+SLOPE(C=2)*PT**2).
No description provided.
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.
No description provided.
NEW VALUES OF ELASTIC SLOPE USING APPARATUS DESCRIBED IN U. AMALDI ET AL., PL 43B, 231 (1973).
We present the first results of a measurement of the total cross-section σ T in proton-proton collisions at equivalent laboratory momenta between 291 and 1480 GeV/ c at the CERN Intersecting Storage Rings (ISR). The method is based on the measurement of the ratio of the total interaction rate and the machine luminosity. The data show an increase of about 10% in σ T in this energy interval.
No description provided.
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.
No description provided.
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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.
No description provided.
SMALL -T DEUTERIUM CORRECTION APPLIED USING MC GEE WAVE FUNCTION (PAPER ALSO GIVES UNCORRECTED AND HULTHEN CORRECTED DATA).
The differential cross section has been measured using 940 events from the BNL 30-inch deuterium bubble chamber. Events were selected without regard to length of the deuteron, and so wide-angle scatters are included. The data are fitted well by a Glauber model with reasonable assumptions about the parameters.
No description provided.
INTEGRATED CROSS SECTION USING EXPONENTIAL FIT TO FORWARD PEAK (SLOPE = 25.2 +- 1.4 GEV**-2).
We have studied the K ππ system in the 14.3 GeV/ c reactions K − p → K − π + π − p, K − p → K 0 π − π 0 and K − p → K 0 π + π − n . The data have been obtained from a 500 000 picture exposure of the CERN 2m HBC. The first two final states are dominated by Q-production in the Kππ system; there is also an L-signal at M (K ππ ) ∼ 1.75 GeV. The reaction cross sections are compared to K − p data at other energies. We discuss the K ππ mass dependence of the diffractive production slope. Evidence is presented for a Q − p versus Q + p differential cross section cross-over around | t | = 0.17 GeV 2 . A t -channel isospin analysis for the KN → K ∗(890)π N channels in the Q-region shows that the I = 1 exchange amplitude is ⋍ 10% of the dominant I = 0 exchange amplitude. The K ππ decay distributions indicate a predominant J P = 1 + state in the Q-region, and an important J P = 2 − contribution in the L-region. We find neither s -channel nor t -channel helicity conservation at the meson vertex in the Q- or L-regions. The K π angular correlation moments within the K ππ diffractive system are characteristic of K π elastic scattering, suggesting a π -exchange Deck-type production mechanism. There is evidence for a Kf 0 and κπ contribution (where κ is the J P (K π ) = 0 + state) to the diffractive K ππ system. A fit to the K − π + π − and K 0 π − π 0 Dalitz-plot distributions for the Q-re gion indicates that the ratio of K ϱ to K ∗ π decay amplitudes decreases with increasing K ππ mass.
No description provided.
The differential cross sections for the reaction γ + n → π 0 + n have been measured at pions angles of 45°, 60°, 105°, 120° and 140° in the c.m.s. for photon energies of 500–900 MeV. Both π 0 meson and recoil neutron from a liquid deuterium target were detected with a pair of Čerenkov counters combined with lead spark chambers and a hodoscope consisting of 16 modules of plastic scintillation counters.
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