Resonance production has been studied in the annihilation process p n aarπ + π - π - π 0 induced by antiprotons in the 0.4 to 0.9 GeV/ c momentum range. We observe strong production of ϱ mesons, together with some f 0 (predominantly in the ϱf 0 channel), ω 0 and A 2 mesons and there is a strong ϱϱ signal. We also observe a broad (~300 MeV/ c 2 ) enhancement at ~1100 MeV/c 2 in the π + π - π - invariant-mass distribution, whereas no such enhancement is seen in the π + π - π 0 channel; we have considered various explanations for this enhancement, including an “A 1 ” effect and interference between amplitudes for conventional resonance production.
FITTED PERCENTAGE OF EACH RESONANCE CHANNEL. THE AUTHORS ALSO QUOTE VERY SIMILAR RESULTS FOR THREE OTHER FITS WHICH ALLOW FOR THE <A1(1100)- PI0> CHANNEL OR BOSE-EINSTEIN INTERFERENCE.
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.
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.
The production of electron-positron pairs of masses below 1200 MeV/ c 2 and of transverse momentum above 1.8 GeV/ c has been studied in pp collisions at √ s = 53 and 63 GeV. The cross section for ϱ, ω, and φ production are presented. The continuum below 600 MeV/ c 2 is consistent with origination from Dalitz decays of η and ω mesons and from semileptonic decay of D and D mesons.
No description provided.
We have studied the production and decay of the D(1285) meson in the reaction K − p→ Λ D at an incident K − momentum of 4.2 GeV/ c . The cross section for this reaction is 11 ± 3 μ b and the branching ratios D→ KK π /D → ηππ and D → 4 π /D → ηππ are found to be 0.42 ± 0.15 and 0.7 ± 0.5, respectively. The proportion of D → ηπ + π − going through the intermediate δ ± π ∓ states is 0.72 ± 0.15. Forward and backward exchange mechanisms are found to contribute in the ratio 3 : 2.
ABOUT 60 PCT OF THE D(1285) PRODUCTION OCCURS IN THE FORWARD HEMISPHERE.
We present results on charged current inclusive neutrino and antineutrino scattering in the neutrino energy range 30–200 GeV. The results include a) total cross-sections; b)y distributions; c) structure functions; and d) scaling violations observed in the structure functions. The results, as well as their comparison with the results of electron and muon inclusive scattering, are in agreement with the expectations of the quark parton model and QCD.
THE VALUES OF Q2 CORRESPONDING TO THE 6 DATA POINTS ARE 1.126,2.11,3.52,4.92,6.33,7.74.
THE VALUES OF Q2 CORRESPONDING TO THE 7 DATA POINTS ARE 1.27,2.25,4.22,7.04,9.85,12.66,15.48.
THE VALUES OF Q2 CORRESPONDING TO THE 8 DATA POINTS ARE 2.11,3.75,7.04,11.72,16.4,21.1,25.8,30.5.
Inclusive and semi-inclusive cross sections for gp0 production in 100, 200, and 360 GeV/c π−p interactions are presented. Differential cross sections for ρ0 production as functions of c.m. rapidity and transverse momentum are compared with the corresponding differential cross sections for pion production. Effects of various methods of estimating background on the values obtained for ρ0 production cross sections are discussed. About 10% of the final-state charged pions appear to come from ρ0 decay. Thus, while ρ0 production and decay is a significant source of final-state pions, other sources must contribute the majority of the produced pions.
No description provided.
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A neutral beam designed to transmit a high flux of Λ0 hyperons with momenta above 50 GeV/c has been built and operated at Fermilab. Inclusive production cross sections per target nucleus have been measured for p+A→Λ0+X, p+A→KS0+X, and p+A→Λ¯0+X with 300-GeV protons incident on solid targets A=berylium,copper,andlead. The region of phase space covered is predominantly projectile fragmentation: 0.2<~x<~1, 0<~p⊥<~2 GeV/c. The A dependence of the inclusive cross sections is analyzed. The cross sections are compared to other work in pp collisions by extrapolating the A dependence to A=1. The results of measurements of Λ0 and Λ¯0 polarization from the beryllium target are presented.
No description provided.
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High-statistics measurements of the absolute differential cross section for n−p scattering have been made over neutron c.m.-system scattering angles 9.5°<θ*<64.5°. The statistical error is 1.7 to 3.3% for 2°-wide angular bins, and the systematic error is 2.7 to 3.3%. The cross section is fitted by dσdΩ*=A exp(bt), with A=10.27±0.36 mb/sr, b=5.00±0.05, and 0.01<−t<0.39 (GeV/c)2. For the ratio of the real to the imaginary part of the forward-scattering amplitude we obtained αn>~−0.43±0.04, consistent with other less precise determinations of αn.
EXPONENTIAL FIT TO D(SIG)/DOMEGA OVER -T = 0.01 TO 0.39 GEV**2 (THETA = 9.5 TO 64.5 DEG).
We present measurements of the production symmetric high-mass hadron and pion pairs by protons of 200, 300, and 400 GeV, incident on a beryllium target. The two-particle invariant cross section for pion production can be described by the function E1E2d6σdp13dp23=(1.7×10−28)pt−8.4(1−xt)14 cm2/GeV4 (where pt is the mean pt of the two hadrons). Functions of the same form have been used in describing single-pion inclusive production. Equality of the exponents of pt in the two processes is observed, confirming the role of smearing contributions to single-hadron cross sections.
E*D3(SIG)/D3(P) is fitted by CONST*(1-XT)**POWER*PT**POWER.
E1*E2*D6(SIG)/D3(P1)/D3(P2) is fitted by CONST*(1-XT)**POWER*PT**POWER, where PT is (pt1 + pt2)/2.
The polarization in K + n↑ → K 0 p has been measured at 6 and 12 GeV/ c in the interval 0.1 < |t| < 1.0 using a polarized deuteron target. The results are compared to predictions from SU(3), exchange degeneracy (EXD) and line reserval, and from various phenomenological models.
NARROW BINS.
WIDE BINS.
No description provided.
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