We present results from a measurement of the differential cross sections for Σ−p, Ξ−p, and π−p elastic scattering at 23 GeV/c. We have collected samples of 6200 Σ−p events, 67 Ξ−p events, and 30 000 π−p events in the interval 0.10<|t|<0.23 (GeV/c)2.
No description provided.
No description provided.
Evidence is presented for a new meson resonance at 2340±20 MeV, with a width of 180±60 MeV, decaying primarily into ρρπ. The resonance, which is observed in 15-GeV/c π+p interactions, has isotopic spin 1 or 2 and odd G parity. The cross section for production of the ρρπ state is 7.3±1.7 μb. Branching ratios into ρρπ and other decay modes are given.
No description provided.
The ωπ − mass spectrum, in the reaction π −p → ωπ − pat 11.2 GeV/ c , shows the production of the B − meson with a cross section of 27 ± 5 μb as well as a clear enhancement around 1670 MeV. In the differential cross section for B − production, there is a strong forward peak and a change of slope at t ' t 0.2 GeV 2 .
CORRECTED FOR BACKGROUND AND OMEGA TAILS.
No description provided.
ABS(D-WAVE/S-WAVE) = 0.4 +- 0.1 FOR B DECAY.
Elastic Σ − p and π − p cross section have been measured at 17.2 GeV/ c in the t interval −0.12, −0.38 (GeV/ c ) 2 . The Σ − p slope is b = 8.12 ± 0.35 (GeV/ c ) −2 .
No description provided.
NORMALIZED TO PI- P ELASTIC FORWARD DIFFERENTIAL CROSS SECTION OF 31.2 +- 1.9 MB/GEV**2 (PLUS 6 PCT SYSTEMATIC ERROR) OF K. J. FOLEY ET AL., PRL 11, 425 (1963).
NUMERICAL VALUES SUPPLIED BY J. J. BLAISING AND ADDED TO RECORD ON 19 DEC 77.
We have measured the total and differential cross-sections for coherently photoproduced ϱ, ω and ϱ′ on deuterium at 7.5 GeV. Using VDM relations, we have obtained γ ω 2 / γ ϱ 2 = 7.1 ± 1.5, σ T ( ϱ d) = (54 ± 2) mb and σ T ( ω d) = (56 ± 5) mb. Assuming the amplitude for ϱ′ production via an intermediate ϱ 0 to be small and that the amplitudes for ϱp and ϱ′p elastic scattering are comparable, we found γ ϱ ′ 2 / γ ϱ 2 = 6.0 ± 1.2 and σ T ( ϱ ′d) = (47 ± 6) mb.
No description provided.
FROM AN EXPONENTIAL FIT WITH DEUTERON FORM FACTOR.
The reaction γ + p → Φ + p has been measured using a spark chamber spectrometer and a tagged photon beam in the energy range from 4.6 to 6.7 GeV. Approximately 3500 photoproduced elastic Φ-events have been collected in the t -range between t min and t = −0.4 (GeV/ c ) 2 . Cross sections and t -distributions are presented.
NO MARKED ENERGY DEPENDENCE.
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.
No description provided.
None
No description provided.
No description provided.
None
SIG(C=BACKWARD) = SIG(-UP<1 GEV**2)/(1-EXP(-SLOPE)). UP DISTRIBUTION OF EVENTS HAS A PERFECT EXPONENTIAL SHAPE.
The differential cross section for elastic scattering of 3.63−GeVc π− mesons on protons was studied with a hydrogen bubble chamber, the emphasis being on large-angle scattering. From 90 to 180° in the barycentric system, the cross section is roughly flat with an average value of 2.7±1.0 μb/sr. Near and at 180°, there may be a slight peak of magnitude 10±6 μb/sr. But if such a peak exists, it is only one-third to one-fourth the size of the 180° peak found in 4.0 GeVc π++p elastic scattering. In addition to comparison with other π−+p and π++p large-angle elastic-scattering measurements, this measurement is compared with large-angle p+p elastic scattering. In the forward hemisphere a small peak or a plateau exists at cos θ*=+0.60. This appears to be a second diffraction maximum such as has been found in lower-energy π+p elastic scattering. A survey of indications of such a second diffraction maximum in other π+p measurements shows that it always occurs in the vicinity of −t=1.2 (GeVc)2, where t is the square of the four-momentum transfer. As the incident momentum increases, the relative size of this second maximum decreases.
No description provided.
No description provided.
Cross sections for the reactions γp→K+Λ and γp→K+Σ0 have been measured at squared four-momentum transfer (−t) from 0.005 to 2 GeV2, at photon energies 5, 8, 11, and 16 GeV. For −t>0.2 GeV2 each of the K+ cross sections is about ⅓ of the π+n photoproduction cross section, having nearly the same energy and momentum-transfer dependence. The K+ cross sections fall off at small |t|, however, in contrast to the sharp forward spike seen in π+n; this leads to a disagreement with an SU(3) prediction for −t<0.1 GeV2. The ratio of K+Σ0 to K+Λ cross sections is typically between 0.5 and 1.0.
'1'.
'1'.
'1'.
None
CORRESPONDING PI+ P CROSS SECTIONS QUOTED. SECONDARY INTERACTIONS OF RHO0 AND DEL- WITH INTRANUCLEAR NUCLEONS SUPPRESSES SIG COMPARED WITH PI+ P DATA.
None
THE ERRORS INCLUDE THE UNCERTAINTIES IN THE FIT PARAMETERS SLOPE AND SIG, WHILE THE PURELY STATISTICAL ERRORS ARE ALSO GIVEN.
We have measured large-angle electron-positron pairs from the reaction γ +Be → Be+e + +e − in the e + e − invariant-mass region of 610 < m < 850 MeV/ c 2 . The phase of the photoproduction amplitude of the ϱ-meson at 4.1 – 6.1 GeV was found to deviate from pure imaginary by 11.8° ± 4.4° which corresponds to a ratio of the real to imaginary ϱ-nucleon amplitude of β = −0.2 ± 0.1.
No description provided.
The elastic scattering of 3.6 GeV/ c π + mesons by protons has been studied in a hydrogen bubble chamber experiment. The elastic cross section has a measured value of 7.07 ± 0.20 mb. The forward diffraction peak has been fitted in the region 0.05 ≦ − t ≦ 0.6 (GeV/ c ) 2 by a form (d σ /d t ) = Ae Bt , where A = 46.5 ± 1.8 mb/(GeV/ c ) 2 and B = 6.85 ± 0.20 (GeV/ c ) −2 . From this fit and the optical theorem, the magnitude of the ratio of real to imaginary forward amplitude is 0.39 ± 0.06, in reasonable agreement with dispersion relation calculations and simple Regge model predictions.
No description provided.
No description provided.
No description provided.
A comparison is made of the properties and production mechanisms of the π + ω and K − ω systems produced in the reactions π + p → π + ω p at 4, 5, 8 and 16 GeV/ c and K − p → K − ω p at 10 and 16 GeV/ c . In the π + ω case apeak is observed at 1.23 GeV (the B meson), while the K − ω mass distribution has a threshold enhancement. The cross section of the low mass (<2.0 GeV) π + ω system falls as p lab −2 , while that of the low mass (<2.0 GeV) K − ω system is almost constant with energy, indicating diffractive production of the K − ω system, but not of the πω system. Using a modified version of the Illinois partial-wave analysis program, it is found that the K − ω system is dominantly produced in the J P = 1 + state with small contributions of 0 − and 2 + , mainly by natural parity exchange - as is found for reactions such as K − p → (K − π + π − )p which are predominantly diffractive. For the π + ω system in the B mass region, J P = 1 + states, produced mainly by natural parity exchange are found; the contributions of 0 − P, 1 − P, 2 − P and 2 + D are consistent with zero. The 1 + D state occurs in the π + ω case but not in the K − ω system, nor in the K ππ − system produced in the K − p → K ππ p reaction.
No description provided.
No description provided.
FROM BREIT-WIGNER FIT TO B EVENTS AND CORRECTED FOR UNSEEN OMEGA DECAY MODES.
A partial-wave analysis of the (K ππ ) 0 system produced in the charge exchange reaction K − p →( K 0 π + π − ) n has been made in the mass range 1.04 ⩽ M (K ππ ) < 1.56 GeV c data at 8, 10 and 16 GeV/ c . It was found that in about 2 3 of the cases, the (K ππ ) 0 system is produced in states of unnatural spin-parity, namely J P = 0 − and 1 + ; the rest is in the natural spin-parity state J P = 2 + state is consistent with being all K ∗ (1420). The unnatural spin-parity states are produced mostly (∼ 80% of the events) by natural parity exchange. The facts that unnatural spin-parity states are produced in this non-diffractive channel, with J P = 1 + dominant, and that the exchange responsible for their production is mostly of natural parity, are similar to what was found for the charged (K ππ ) − system in the diffractive reaction K − p→(K ππ ) − p. However, the absolute value and the energy dependence of the cross sections are very different in the two cases.
CORRECTED FOR UNSEEN AK0 DECAY MODES.
ACTUALLY CROSS SECTIONS FOR PRODUCTION IN MASS REGION 1.04 < M(AK0 PI+ PI-) < 1.56 GEV IN THE STATES JP = 1+, 2+ AND 0- RESPECTIVELY.
The results are presented of two partial-wave analyses of the (3π) − system in 30 000 events of the reaction π − p → π − π − π + p at 11.2 GeV/ c . Both techniques incorporate the assumptions of the isobar model and are (a) the University of Illinois program which fits in terms of the (3π) density matrix elements and (b) an amplitude parametrisaton including possible effects of both spin non-flip and spin flip at the baryon vertex. The results obtained with these independent programs are found to be very close.
NORMALIZED TO A TOTAL REACTION CROSS SECTION OF 1.17 +- 0.24 MB. ALL QUOTED CROSS SECTIONS ARE FOR INTEGRATED BREIT-WIGNERS.
A2 2+D-WAVE FOR 1.2 < M(3PI) < 1.4 GEV. THE FIRST THREE COMBINATIONS OF DENSITY MATRIX ELEMENTS ARE FOR NATURAL PARITY EXCHANGE, AND THE REMAINDER UNNATURAL.
A partial wave analysis of the K 0 π + π − system produced in the charge exchange reaction K − p → ( K 0 π + π − ) n at 4.2 GeV/ c has been performed both as a function of Kππ mass and of t ′. The 1 + S wave forms the largest contribution to the K ππ system and peaks at roughly the same mass as the Q in diffractive K ππ production. The polarization properties of the 1 + S ( K ∗ π) and 1 + S (Kϱ) waves differ fromt those of the diffractive 1 + wave. There is some evidence for a resonance contribution to 1 + S ( K ∗ π) . The strong 2 + wave the K ∗ (1420) and the K ϱ/ K ∗ ϱ decay branching ratio determined to be 0.36±0.10. An enhancement with spin-parity 1 − is observed under K ∗ (1420) .
CROSS SECTION CORRECTED FOR BREIT-WIGNER TAILS, THE TP CUT, UNSEEN <AK0 PI> AND <K RHO> DECAY MODES. BRANCHING RATIO K*(1420) --> <K RHO>/<K* PI> = 0.36 +- 0.10.
No description provided.
Cross sections for γd and γn interactions and photoproduction of ϱ 0 and ω are studied at 4.3 GeV, using a linearly polarized photon beam in a deuterium bubble chamber. We find that σ T (γ n ) ⋍ σ T (γ p ) within about 5% and that the γn average charge multiplicity is lower than γp by 0.42±0.09. About 4000 ϱ 0 events and 70 coherent ω events are observed. We present total and differential cross sections for both xoherent and incoherent ϱ 0 production on deuterium, as well as decay angular distributions and density-matrix elements. We find that the t -channel isospin-one exchange amplitude in γ N → ϱ 0 N (e.g. A 2 exchange) is at most 5–13% of the dominant isoscalar amplituds. The ϱ 0 production mechanism is dominantly s -channel helicity-conserving (SHC) on both neutrons and protons. We find that relative to the SHC amplitudes, the single and double helicity-flip amplitudes at the γϱ 0 vertex are of the order of 10–15% for | t | > 0.25 GeV 2 , and have the same sign on both nucleons. This shows that helicity-flip is mainly due to isoscalar exchanges. The ratio of ω to ϱ 0 coherent forward cross sections is found to be 0.16±0.04. The natural-parity exchange part of γ N → ω N is strongly dominated by isoscalar exchanges, and the magnitude of the isovector-exchange is consistent with zero.
TOPOLOGICAL CROSS SECTIONS AND AVERAGE CHARGE MULTIPLICITIES GIVEN IN TABLE 1.
'PARAMETRIZATION'.
No description provided.
None
No description provided.
The reactions Λ p → Λ p, → Σ ± p π ∓ , → Λ p π + π − and → Σ 0 p have been studied in the SLAC 82 inch bubble chamber for incident Λ particles in the momentum range 1–10 GeV/ c . The incident Λ flux was produced by the exposure of a platinum target mounted inside the chamber to a 12 GeV K − beam. A total of 992 events have been analyzed. The reactions are found to be qualitatively similar to corresponding nucleon-nucleon reactions. In particular, the slope parameter B in the elastic cross section d σ /d t = A e Bt has been determined as a function of incident momentum and found to be consistent with that for proton-proton elastic scattering. Angular distributions for the inelastic channels are compared with those of similar nucleon-nucleon reactions, and predictions of relevant exchange models.
IN BINS OF EQUAL INCIDENT LAMBDA PATH-LENGTH.
IN 100 MEV/C BINS.
No description provided.
We report on a search for Ξ* production in the mass range 1.5-2.0 GeV / c2 in K−n interactions at 2.87 GeV / c. Upper limits on Ξ* production cross sections, as well as reaction cross sections for those final states in which Ξ*'s may be observed, are presented. In particular, an upper limit of 5.4 μb is placed on production of an isospin-−32 Ξ*−−.
CROSS SECTIONS ARE QUOTED FOR THE SAME FINAL STATE DERIVED FROM DIFFERENT TOPOLOGIES.
UPPER LIMITS AT 90 PCT CONFIDENCE LEVEL FOR RESONANCE ABOVE SMOOTH BACKGROUND.
No description provided.
The production of ρ 0 (770) and f(1270) is studied in π − p interactions at 16 GeV/ c . By comparison with inclusive K ∗0 production in the reaction K − p → K ∗0 + anything, and with inclusive ρ 0 production in the reaction pp → ρ 0 + anything, it is found that the data can be interpreted in terms of two production processes: the central production of resonances and the fragmentation of the beam particle. For the π − p reaction, the inclusive ρ 0 beam fragmentation cross section is 3.1 ± 0.3 mb while that for central production is 1.6 ± 0.5 mb. The ρ 0 central production cross section is consistent with increasing with energy as ln s behaviour. The ratio of ρ 0 to π − inclusive cross sections (excluding the leading π − ) is ∼0.2, independent of energy. The ρ 0 to π − ratio increases as a function of p T to a constant value of ∼ 1 2 above 1 GeV/ c . The ρ (charged and neutral) and f decays account for (25 ± 4)% and (1.4 ± 0.3)%, respectively, of all pions produced.
No description provided.
No description provided.
No description provided.
The general features of p p interactions at 32 GeV/ c are analysed in a bubble chamber experiment with a statistics of 5.2 μb/event. The inclusive production of neutral strange particles and pions is analysed and compared to results obtained at other energies and in pp interactions. Total cross sections are determined for various 4C reactions and the relative contributions of diffractive dissociation and Δ Δ production to the reaction p p → p p π + π − are estimated.
No description provided.
TOTAL CROSS SECTIONS FOR 4C REACTIONS.
We have remeasured the total cross section for proton-proton scattering at 2-6 GeV/c in the spin states ↑↑ and ↑↓ perpendicular to the beam direction. With the reduced errors significant differences were found between the two cross sections.
DIFFERENCE OF TOTAL CROSS SECTIONS FOR ANTIPARALLEL AND PARALLEL SPINS PERPENDICULAR TO THE BEAM DIRECTION.
No description provided.
Cross sections are presented for production of final states with two strange particles from π+p interactions at 10.3 GeV/c in a 31.1-event/μb bubble-chamber experiment.
No description provided.
No description provided.
The polarization parameter P for the reactions p p → π − π + and p p → K − K + has been measured over essentially the full angular range at ll laboratory momenta between 1.0 and 2.2. GeV/ c , using a proton target polarized perpendicular to the scattering plane. The angles and momenta of both final state particles were determined from wire spark chambers, using the deflection caused by the polarized target magnet. Between 1000 and 5300 π − π + events, and 140 and 1300 K − K + events, were measured at each momentum. Differential cross sections for p p → π − π + were obtained. These are in excellent agreement with previous results. The polarization parameter for both channels is very close to +1 over much of the angular range. Legendre polynomial fits to the data are presented.
THE DIFFERENTIAL CROSS SECTIONS IN THIS EXPERIMENT AGREE WITH THE ONES FROM THE AUTHORS' EARLIER EXPERIMENT (E. EISENHANDLER ET AL., NP B96, 109(1975)) USING A LIQUID HYDROGEN TARGET, THOUGH THEY DO NOT CONSIDER THE PRESENT ONES QUITE AS RELIABLE.
No description provided.
No description provided.
Polarization in π − p elastic scattering, with emphasis over the backward region, has been measured at 2.93 and 3.25 GeV/ c . We observe large changes in polarization compared with existing data above and below these energies. Our data may be useful in determining the properties of resonances and in understanding baryon exchanges.
THESE DATA, TOGETHER WITH THE FORWARD SCATTERING POLARIZATION MEASUREMENTS, ARE TABULATED IN THE RECORD OF P. AUER ET AL., PRL 37, 83 (1976).
A study of 205-GeV/c π−p interactions has been made with a 48 800-picture exposure in the bare Fermilab 30-inch hydrogen bubble chamber. The average number of charged particles produced per inelastic interaction is 7.99±0.06. The elastic cross section is 3.18±0.13 mb and the total cross section is 24.19±0.44 mb. The inclusive cross sections for neutral-particle production are: σ(γ)=171.3±15.3 mb, σ(KS0)=3.64±0.61 mb (x<0.3), σ(Λ)=1.71±0.34 mb (x<0.3), and σ(Λ¯)=0.59±0.23 mb (x<0.1). The average number of π0's produced per inelastic collision is consistent with a linear rise with the number of charged particles, and about equal to the number of produced π− or π+. The average number of K0's, Λ's, and Λ¯'s is consistent with very little dependence on the number of charged particles. General characteristics of neutral-particle production are presented and compared with other experiments. For each topology the produced neutral energy is ∼13 of the incident energy.
No description provided.
No description provided.
No description provided.
Results are presented concerning topological cross-sections and multiplicity distribution for a π−p experiment at 11.2 GeV/c. The statistics used are one-half of the total ones (106 bubble chamber pictures). Comparison with data at different energies and theoretical predictions are made, and satisfactory agreement is obtained.
TABLE ALSO QUOTES PRONG CROSS SECTIONS FOR PRODUCTION OF VEE(S).
We have measured charged-particle multiplicities and elastic and inelastic cross sections for π+p and pp interactions at 60 GeV/c. The data are from a 30 000-picture exposure of the 30-inch bubble chamber to a tagged but unseparated positive-particle beam at Fermilab. The low-order moments of the inelastic multiplicity distributions for all charged particles are 〈n〉 = 5.60±0.09, f2 = 0.96±0.31, and 〈n〉D = 2.19±0.06 for pp reactions and 〈n〉6.23±0.10, f2 = 1.63±0.37, and 〈n〉D = 2.22±0.06 for π+p collisions.
NORMALIZED TO A TOTAL CROSS SECTION OF 38.3 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.
NORMALIZED TO A TOTAL CROSS SECTION OF 23.2 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.
FORWARD CROSS SECTIONS ARE CONSISTENT WITH OPTICAL POINT FOR PURELY IMAGINARY ELASTIC AMPLITUDES.
In a sample of 108 563 pictures taken with the Fermilab 30-inch hydrogen bubble chamber, exposed to a 360-GeV/c π− beam, we have observed 19 453 interactions in a selected fiducial region. The observed charged multiplicity distribution has been corrected for the effects of scan efficiency, errors in prong count, missed close-in vees, secondary interactions, and neutron stars and for Dalitz pairs. The two-prong events have been corrected for losses at low −t. The total cross section is measured to be 25.25 ± 0.35 mb, and the elastic cross section is 3.61 ± 0.11 mb with an exponential slope of (8.82 ± 0.30) (GeV/c)−2. The average charged-particle multiplicity for inelastic events is 8.73 ± 0.04, and the second moment f2 is measured to be 9.83 ± 0.23.
SYSTEMATIC CORRECTIONS INCLUDED IN ERRORS.
FROM FIT, FORWARD D(SIG)/DT = 31.84 +- 0.68 MB/GEV**2, AND AGREES WITH OPTICAL POINT FROM MEASURED TOTAL CROSS SECTIONS.
Results are presented concerning K − d and K − n elastic scattering at an incident momentum of 4.5 GeV/ c . The high-energy Glauber formalism has been used in analyzing the data in which the nucleon scattering amplitudes are parameterized and employing the spherical and quadrupole deuteron form factors. An impulse approximation analysis of the K − n differential scattering cross section fitted to a single exponential of the form d σ /d t ) 0 e Bt , leads to the result (d σ /d t ) 0 = 21.3 + mn ; 5.5 mb/(GeV/ c ) 2 and B = 6.9 + mn ; 0.5 (GeV/ c ) −2 . A global fit has been made to existing K + mn; N two-body scattering data at this energy in order to determine the scattering amplitudes. It was found that the K − n and K − p elastic amplitudes are dominantly imaginary with a relatively small contribution from spin-flip amplitudes. The slopes of the differential elastic cross sections for K − n and K − p are nearly equal, as are those for K + n and K + p. However, the value of the slope for K + is smaller than that for K − at this energy.
No description provided.
No description provided.
No description provided.
None
No description provided.
The results presented in this paper were obtained from a 105 000 frame exposure of the FNAL Hybrid Proportional Wire Chamber-30 inch Bubble Chamber System, in a tagged beam of 147 GeV/ c negative particles. Elastic, total and topological cross sections were obtained for both π − p and K − p interactions. Comparisons with other data, taken with various beam particles over large momentum intervals, show good agreement with KNO scaling, and similarity in the scaling behavior of σ n for the different beam particles.
THESE CROSS SECTIONS ARE NOT NORMALIZED TO ANY OTHER ABSOLUTE MEASUREMENT. THE ERRORS INCLUDE SOME SYSTEMATIC ERRORS.
THE FORWARD CROSS SECTION AGREES WELL WITH THE OPTICAL POINT FROM TOTAL CROSS SECTION MEASUREMENTS.
THESE CROSS SECTIONS ARE NOT NORMALIZED TO ANY OTHER ABSOLUTE MEASUREMENT.
We report the results of a study of the reaction p p → p + x at 32.1 GeV c , where the recoiling proton has a small laboratory momentum. The reaction is studied in the 4.5 m Mirabelle bubble chamber at Serpukhov. We compare the diffractive dissociation of the incident antiproton to other incident particles.
No description provided.
CALCULATED USING THE OPTICAL THEOREM AND THE TOTAL CROSS SECTION FOR AP P OF 46 +- 0.3 MB.
TOPOLOGICAL AND BEAM DIFFRACTION CROSS SECTIONS WITH PLAB(FINAL STATE PROTON) < 1.1 GEV/C.
Results are presented on the topological cross sections obtained for antiproton-proton interactions from an exposure of the Fermilab 30-inch bubble chamber to a 100 GeV/ c negative beam enriched in p 's. The p p inelastic cross section is found to be σ inel = 34.6 ± 0.4 mb, and the average inelastic charged particle multiplicity to be 〈 n 〉 = 6.74 ± 0.05.
ERRORS ARE STATISTICAL ONLY EXCEPT FOR 2-PRONG CROSS-SECTIONS.
EXPONENTIAL FIT TO ELASTIC T DISTRIBUTION TO CORRECT FOR AN APPARENT LOSS OF EVENTS AT SMALL -T.
MOMENTS OF 100 GEV/C AP P MULTIPLICITY DISTRIBUTION.
The results on total channel cross-sections obtained in the 2 m HBC exposed to a separated K− beam at the CERN PS are presented here. The total cross-sections for each channel are given at seven incident K− momenta between 1.934 and 2.516 GeV/c.
CORRECTED FOR ALL POSSIBLE V DECAY MODES. STATISTICAL ERRORS ONLY.
We have measured the total cross-section difference for pp scattering in initial spin states parallel to the beam direction at beam momenta of 1.17, 1.47, 1.69, 1.97 and 2.49 GeV/ c . This measurement was done in a standard transmission experiment. A striking energy dependence is observed with a maximum difference of −16.9 mb at P lab = 1.47 GeV/ c .
PRELIMINARY RESULTS.
PRELIMINARY RESULTS.
Polarization in π−p elastic scattering, with emphasis in the region around the secondary dip and also θc.m.=90°, has been measured at 2.93 and 3.25 GeV/c. We observe an interesting sign change in this angular region.
No description provided.
No description provided.
Results are given from a study of 15 518 events of the reaction K + d → K + π − pp. The K + π − spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K + π − → K + π − elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier K π scattering studies using the reaction K + p → K + π − Δ ++ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.
No description provided.
The elastic cross section for proton proton scattering at 6 GeV c was measured using a 70% polarized beam and a 75% polarized target at the Argonne ZGS. In the range P ⊥ 2 = 0.5 → 2.0( GeV c ) 2 we obtained small error measurements for the ↑↑, ↓↓ and ↑↓ initial spin states perpendicular to the scattering plane. At P ⊥ 2 = 0.5 we also measured the recoil spin and found that the 5 different cross sections were very unequal.
No description provided.
No description provided.
An experiment was done using an accelerated polarized proton beam and a polarized proton target. The elastic cross section for proton-proton scattering at 6.0 GeV/c and P⊥2=0.5−1.6 (GeV/c)2 was measured in the spin states ↑ ↑, ↓ ↓, and ↑ ↓ perpendicular to the scattering plane. The cross sections were found to be unequal by up to a factor of 2.
No description provided.
The reaction p p → K ∗ K does not exhibit any s -channel resonance effect between 1 and 2.5 GeV/ c . On the contrary, the data on p p → K ∗∓ K ± are compatible with an exchange mechanism in the t - and u -channels above 1.5 GeV/ c . Strong similarities are found with p p → K − K + and K ∗− K ∗+ . The polarisation of K ∗± is given. The reaction p p → K ∗0 K 0 vanishes above 1.5 GeV/ c
No description provided.
LEG(L=0) = SIG/(4*PI).
LEG(L=0) = SIG/(4*PI).
A thin polyethylene target was exposed to the internal proton beam of the Serpukhov accelerator at 30, 50, and 70 GeV. The wide-angle recoil protons were registered by photoemulsion stacks and the differential cross sections of the elastic p−p scattering in the range of four-momentum transfer squared 0.0025≤|t|≤0.12 (GeV/c)2 were measured. The ratio of the real to the imaginary part of the forward nuclear amplitude α, the slope parameter of the diffraction peak b, and the total elastic cross section σel were found to be as follows: at 30 GeV, α=−0.183±0.051, b=10.61±0.27 (GeV/c)−2, σel=7.7±0.2 mb; at 50 GeV, α=−0.068±0.040, b=11.25±0.28 (GeV/c)−2, σel=7.0±0.2 mb; at 70 GeV, α=−0.104±0.065, b=11.21±0.40 (GeV/c)−2, σel=7.1±0.2 mb.
No description provided.
No description provided.
No description provided.
We present experimental results and a partial-wave analysis of the low-mass ( K π) 0 systems produced in the reactions K − p → K π N at 14.3 GeV/ c . The main results concern the production mechanisms of the K ∗ (890) and K ∗ (1420) . We also extract the s-wave component of the K π system as a function of mass.
THE ERRORS QUOTED (EXCEPT FOR THE FIRST REACTION) ARE MAINLY AN ESTIMATE OF THE SYSTEMATIC UNCERTAINTIES.
No description provided.
No description provided.
Transversity amplitudes and spin density matrix elements are determined for the process K − p → (π + π − ) s-wave ϵ 0 (1385). Predictions of the additive quark model and of duality diagrams are tested and found consistent with the data; this is the first information about the applicability of these models to processes where a scalar object is produced at the mesonic vertex.
No description provided.
An enhancement in the (K − π + ) mass distribution at 1871 ± 10 MeV with full width of 285 ± 40 MeV is observed in the charge-exchange reaction K − p → K − π + n at 10 and 16 GeV/ c . The energy dependence of its cross section, the shape of the differential cross section d σ /d t and the decay angular distributions are consistent with a production mechanism by pion exchange. No significant enhancement at the same mass is seen in the non-charge exchange reaction K − p → (K π ) − p. The experimental evidence is reviewed and it is suggested that there may be more than one K ∗ enhancement in the 1700–1900 mass region.
FOR ALL EVENTS WITH 1.7 < M(K- PI+) < 2 GEV. NO FORWARD DIP. 'THETA CUT'.
THE 14.3 GEV/C POINT IS FROM ANALYSING THE DATA OF M. SPIRO ET AL., PL 60B, 389 (1976) IN THE SAME WAY. 'THETA-CUT'.
The total cross section for hadron production by high-energy photons has been measured from a number of nuclei ranging from hydrogen to uranium. Some shadowing is observed at a level considerably less than predicted by conventional vector-meson dominance but consistent with a modified theory. The energy dependence predicted by vectormeson dominance is observed. The shadowing in heavy nuclei shows a smooth transition from electroproduction to photoproduction.
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