The ratio (p¯d→π−π0ps)(p¯d→π−π+n) at rest, with spectator momenta ≲300 MeVc, has been measured and found to be 0.68 ± 0.07. This implies that (75 ± 8)% of the annihilations in deuterium into two pions come from odd N¯N orbital angular momenta, in disagreement with the S-state-dominance hypothesis. It has also been observed that the p¯d→π−π0ps production rate depends on the spectator momentum, which suggests energy-sensitive N¯N phenomena near threshold.
RELATIVE ANNIHILATION FREQUENCY AT REST.
The inelastic reaction p+p→p+X is studied at 205 GeV/c. The distribution of the square of the missing mass, M2, shows a large diffractivelike peak at low M2 due to two-, four-, and six-prong events. The slope of the invariant cross section versus t decreases with increasing M2. The energy dependences of the multiplicity moments for the recoiling system X are similar to those for corresponding moments for p+p→(n chargedparticles).
No description provided.
The polarization parameter P(t) for the reaction π−p→π0n has been measured at 3.5 and 5.0 GeV/c over the range 0.2<~−t<~1.8 (GeV/c)2. The two γ rays from the π0 decay were detected in a large lead-glass hodoscope. The results agree with the positive polarization values found in earlier Argonne National Laboratory data at −t<0.35 (GeV/c)2. P(t) drops to a small value near t=−0.6 (GeV/c)2 and remains the same out to t=−1.8 (GeV/c)2.
DATA POINTS MEASURED FROM SMALL GRAPH.
The differential cross section for π−−p elastic scattering has been measured at 13.8 and 22.6 GeV/c up to −t=5 (GeV/c)2. The dips in the angular distribution at −t≈0.8 and 2.8 (GeV/c)2 previously observed at lower momenta become less prominent at higher momentum. The −t=2.8 (GeV/c)2 dip is still observed at 13.8 GeV/c, but at 22.6 GeV/c it has become a sharp kink in the angular distribution. At large momentum transfers, dσdt at fixed t is still decreasing with increasing s, but at a slower rate in the 14- to 23-GeV/c region than at lower momenta.
No description provided.
No description provided.
We have measured the total cross section for electron-positron annihilation into three or more hadrons, with at least two charged particles in the final state. The measurement was made at a center-of-mass energy of 4 GeV with a 2π−sr nonmagnetic detector. With 88 events detected, we obtain a model-independent lower limit on the hadron production cross section of 9.6 ± 1.4 nb; a calculation of detection efficiency based on invariant phase-space production of pions leads to a total cross section of 26 ± 6 nb. This cross section is 4.7 ± 1.1 times the theoretical total cross section for e+e−→μ+μ−. The average charged multiplicity is n¯=4.2±0.6.
No description provided.
Momentum spectra for forward Σ− production on beryllium by protons of momentum 25.8 and 29.4 GeVc are presented. Data for the two primary proton momenta are compared for scaling behavior in the invariant cross section. In addition, the observed single-particle momentum distributions are compared with single-particle spectra from other inclusive reactions initiated by protons.
No description provided.
No description provided.
We have found 431 events of the reaction K+d→K0pps at 3.8−GeVc K+ beam momentum in a 295 000-frame exposure of the Argonne National Laboratory 30-in. deuterium-filled bubble chamber. The event sample consists of one- and two-prong events with a visible K0 decaying to π+π− The total and differential cross sections are found after correction for unseen K0's and for efficiencies in the scanning-measuring-fitting chain. Comparisons of the data are made to an SU(3) sum rule, a Regge model, and data for K−p→K¯0n.
No description provided.
GLAUBER SCREENING AND PAULI EXCLUSION PRINCIPLE CORRECTIONS ARE REQUIRED TO YIELD THE K+ N CHARGE EXCHANGE CROSS SECTION. THE GLAUBER CORRECTION IMPLIES AN INCREASE IN THE CROSS SECTIONS BY THE FACTOR 1.016. THE PAULI CORRECTION IS SLIGHT EXCEPT AT LOW -T (<0.2 GEV**2) WHERE IT IS LARGE AND UNCERTAIN.
We present differential and total cross sections for two reactions: π−p→K0Λ and π−p→K0Σ0. The incident pion momenta were 8, 10.7, and 15.7 GeVc. The results are based on an analysis of approximately 22 600 events of the two reactions where the π+ and π− from the decay of the KS0 were detected in the forward leg of the Double Vee Magnetic Spectrometer. The separation of Λ recoils from Σ0 recoils was accomplished by the missing-mass technique.
No description provided.
No description provided.
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We have studied η′ production using a π+ beam incident on deuterium in the 72-in. bubble chamber, with beam momenta from 1.1 to 2.4 GeVc. Cross sections for reactions leading to five- and six-pronged final states are presented. We observe η′ production in the reaction π+d→ppη′, with the decay mode η′→π+π−η. The cross section for π+n→pη′ (studied in the impulse approximation) is observed to rise to a maximum of about 100 μb at 2.2-GeV c.m. energy. The production angular distribution develops peripheral peaking with increasing energy.
No description provided.
Results from the study of reactions (1) K−d→K−π−π+d and (2) K−d→K−π−π+nps at 7.3 GeV/c are presented. The interactions are dominated by the production of K*(890), ρ(765), Q(1200−1450), and D*(2200) in (1) and Δ−(1236) in (2). Observation of ρ(765) and its possible source as a misidentified K*(890) is discussed. Evidence is observed of splitting of the Q into two resonances with masses and widths (in MeV) M1=1228±21, Γ1=111±33, M2=1414±15, and Γ2=89±24, L(1775) is observed in (1). An off-shell one-pion-exchange-model calculation is compared to (2). Cross sections and branching ratios of the Q resonances are estimated on the basis of the model.
Q (OR K(A)) CROSS SECTIONS MODEL-DEPENDENT WITH BACKGROUND UNSUBTRACTED.
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