The reactions π + p → π + (K + K − )p and pp → p(K + K − )p where the K + K − system is centrally produced have been studied at 85 GeV/ c . The K + K − spectrum contains several structures in the regions of S ∗ ø , f A 2 and f′. Structure is observed in the 1.7 GeV mass region which cannot be attributed to the g meson. The most likely interpretation of the data is that we observe the θ with a mass of 1.742 GeV and a new resonance at a mass of 1.629±0.010 GeV with a width of 0.082±0.030 GeV.
No description provided.
We study the internal structure of a forward-going pπ + π − π + π − system, with invariant mass in the range 2.5-4 GeV, produced through diffractive dissociation of a beam proton at the ISR. The shape of the system, as seen in its center-of-mass, deviates strongly from isotropic phase space and possesses, rather, a longitudinal structure with a major axis along the incoming proton direction. The final state proton momentum is aligned in the direction of the incoming proton, an effect which becomes more pronounced with increasing diffractive mass.
Acceptance corrected distribution of momentum transfer to the diffractive (p-4pi) system. Data requested from authors.
No description provided.
The relative yields of kaons and protons compared with the yield of pions at highpT and polar angles θ away from 90° (in the range from 10° to 45°) are presented forpp, dd, and αα interactions at a centre-of-mass energy\(\sqrt {s_{NN} }= 31\) GeV per nucleon-nucleon collision. The measured particle ratios depend on the atomic mass numberA of the beam particles and on θ. TheA dependence of the ratios becomes stronger for largerpT and is more pronounced at smaller polar angles.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
We present results from a direct photon pair search performed with the NA3 spectrometer, using incident positive and negative beams at 200 GeV/ c interacting with a carbon target. The experiment is sensitive to photons with p T >1.8 GeV / c and −0.4⩽y ∗ ⩽1.0 , one in each arm of the apparatus. A 3 standard deviation signal is seen in τ − and p interactions. The cross section is higher than the second order QCD calculations, but systematic errors are large.
No description provided.
Measurements are presented of two exclusive diffractive reactions, pp → (Λ 0 φ 0 K + ) p and pp → (Λ 0 Λ 0 p)p , at √ s = 63 GeV . Pronounced correlations with the beam direction are observed (in the rest frame of the forward-going bracketed system) for those outgoing particles which contain the beam valence quarks. In each case there is a forward-Λ 0 in correlation with a backward K + or p, respectively. No such behavior is seen for the particles which do not contain beam valence quarks (φ 0 and Λ 0 , respectively) . Interpreted as examples of pomeron-proton scattering, these results constitute evidence that, for these final states, the pomeron interacts with a single valence quark and apparently back-scatters it. The subsequent hadronization leads to a longitudinal event structure.
Cross sections for forward LAMBDA signal counting both arms of the p p interaction.
Cross sections for forward LAMBDA signal counting both arms of the p p interaction.
No description provided.
In an experiment at the CERN intersecting storage rings with √ s = 31 GeV, we have measured αP , the product of asymmetry parameter and polarization, for Λ 0 's and Λ 0 's produced in p p and pp interactions, respectively. The ratio, (αP) Λ /(αP Λ = −1.04±0.29 , is consistent with the value −1, and constitutes the first test of CP invariance in Λ decay.
The ratio CONST/CONST is obtained under assumption of POL(LAMBDA) = POL(LAMBDABAR).
We have studied the inclusive production of strange meson and baryon resonances in 360 GeV/cpp interactions. Cross sections forK*+(892) andK*−(892) are estimated to be 4.42±0.62 mb and 2.54±0.47 mb respectively and those for∑+(1385) and∑−(1385) are 0.67±0.11 mb and 0.26±0.07 mb respectively. Longitudinal and transverse momentum distributions forK*(892) and Σ(1385) are presented, as well as for their decay productsK0 and Λ. An estimation is given on theK*(1430) and∑*(1915) productions.
No description provided.
The spin analyzing power A in 28-GeV/c proton-proton elastic scattering was measured at P⊥2=6.5 (GeV/c)2 using a polarized proton target and a high-intensity unpolarized proton beam at the Brookhaven National Laboratory Alternating Gradient Synchrotron. The result of (24±8)% confirms that the analyzing power is large and rising in the large-P⊥2 region.
No description provided.
Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies s =30.6, 52.8 and 62.3 GeV at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at s =23.5 GeV . Using the optical theorem, total cross sections are obtained with an accuracy of about 0.5% for proton-proton scattering and about 1% for antiproton-proton scattering. The measurement of the interference of the Coulomb scattering and the hadronic scattering permits a determination of the ratio of the real-to-imaginary part of the forward hadronic scattering amplitude. Also presented are measurements of the hadronic slope parameter.
No description provided.
No description provided.
No description provided.
A comparison between p p and pp interactions at √ s = 52.7 GeV is presented for a total neutral transverse energy ( E T o ) trigger and for a high transverse momentum ( p T ) neutral cluster trigger. The rate of production of events in the range 6< E T o <20 GeV is observed to be 10% higher in p p collisions than in pp collisions. A study of the structure of the events shows this excess to be due to more isotropic events being produced in p p collisions. The ratio of the production cross section for single neutral clusters in p p and pp interactions in the range 1.25< p T <10 GeV/ c does not significantly differ from unity.
No description provided.
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