A peak in the pK−π+ and p¯K+π− invariant-mass spectra at 2.285±0.006 GeV/c2 is observed, which is associated with the lowest-lying charmed baryon (Λc). A cross section times branching ratio of 0.037±0.012 nb at Ec.m.=5.2 GeV is measured with a substantial fraction of the events produced with an equal recoiling mass. New measurements of inclusive p and Λ cross sections are also presented, allowing an estimate of the branching ratio B(Λc→pK−π+)=0.022±0.010.
THE TOTAL INCLUSIVE CHARMED LAMBDA CROSS SECTION IS DERIVED FROM THE OBSERVED PRODUCTION RATE VIA THE <P K- PI+> CHANNEL USING THE STEP IN INCLUSIVE PROTON PRODUCTION AT THE CHARMED-BARYON THRESHOLD AND REASONABLE ASSUMPTIONS. THE BRANCHING RATIO (LAMBDA/C+ --> P K- PI+) IS THEN 2.2 +- 1.0 PCT.
ACTUALLY TWICE THE INCLUSIVE ANTI-PROTON CROSS SECTION (EACH BARYON PAIR IS COUNTED TWICE).
EACH BARYON PAIR PRODUCED IS OF COURSE COUNTED TWICE IN THIS CROSS SECTION.
Differential cross sections for the reaction π − p→ η n at 20 incident pion momenta between 724 and 2723 MeV/ c are presented. The results are compared with previous measurements. The data show clear evidence of non-zero couplings of this channel to known I = 1 2 , S = 0 baryon resonances with masses up to 2000 MeV/ c 2 .
No description provided.
No description provided.
No description provided.
Measurements of inelastic electron scattering have been made in the range 2.2 < ν < 3.8 GeV and 0.1 < | Q 2 | < 0.3 (GeV/ c ) 2 , on a selection of nuclei ranging from hydrogen and deuterium to uranium, by measuring the scattered electron only. Detailed calculations have been made of the contribution of radiative tails to the measured yield. The results show a small ‘shadowing’ consistent with other electroproduction experiments, and also with photoproduction experiments in this ν range, but the shadowing decreases rapidly as | Q 2 | increases.
DEUTERIUM TO HYDROGEN CROSS SECTION RATIO (PER NUCLEON). FOR E(P=3) = 2.25 AND THETA = 8.5, THE RATIO IS 0.911 +- 0.037 (DSYS = 0.040).
No description provided.
No description provided.
Final states produced by charged baryon exchange in π − p interactions at 12 GeV/ c laboratory momentum have been studied. Forward neutrons with momenta determined by a calorimeter to be greater than 8.5 ± 1.4 GeV/ c triggered the SLAC 40-inch hydrogen bubble chamber which operated at a 10 Hz expansion rate. We report data on the reactions π − p→n π − π + , π − p→n π − π + π 0 , and π − p→n π − π − π + π + . In π − n π − p→n π + , production of ϱ and f mesons is observed. Differential cross sections are derived and compared with data at lower incident momentum and with theoretical models. In π − p→n π − π + π 0 , ω production is observed with a differential cross section having a deep near u ′= 0.2 (GeV/ c ) 2 . In π − p→n π − π − π + π + , Δ − , ϱ and f production is observed . The observed mass distributions appear to indicate the production of wide resonaces decaying into ϱππ. Some evidence for ϱ-ω interference is also observed.
No description provided.
No description provided.
CORRECTED FOR BACKGROUND.
Results are presented of differential cross-section measurements for the reaction π − p→ π 0 n; π 0 → γγ at 22 incident pion momenta between 618 and 2724 MeV/ c . The results are in good agreement with those of other experiments. They represent the first comprehensive set of high statistics measurements of the π − p charge-exchange differential cross section at closely spaced momenta in the resonance region.
No description provided.
No description provided.
No description provided.
Using bubble-chamber data on the reactions π+d→pspπ0π0, π+d→pspπ+π−, and π−p→nπ+π− at 7 GeV/c incident π momentum, π−π phase shifts are determined for 0.6<M(ππ)<1.5 GeV/c2. An I=0S-wave resonance is observed in the f0 peak region of M(ππ). Constructive ρ−ω interference is found in the reaction π+n→pπ+π− and evidence is presented for some specifically deuteron effects in the data with large spectator-proton momentum.
TWO-PRONG CROSS SECTIONS IN DEUTERIUM WITH SPECTATOR PROTON MOMENTUM CUT AT 0.3 GEV/C.
NOTE THAT THE LOW-T DATA POINTS (<0.1 GEV**2) SHOULD BE CORRECTED FOR PAULI EXCLUSION IN DEUTERIUM.
FROM FIT WITH BREIT-WIGNER RESONANCES PLUS PHASE SPACE.
A quasi-two-body model based on one-particle exchange and diffraction dissociation has been fitted to data from π−p interactions at 3.9 and 11.9 GeV/c in which a nucleon and 3-6 pions are present in the final state. It is used to estimate partial cross sections for the contributing interaction mechanisms and the dominant resonances which are produced at these energies. The energy dependence of the cross sections is examined and found to be consistent with expected behavior, and reactions are compared and found to agree with simple factorization.
No description provided.
No description provided.
No description provided.
Interactions of antiprotons were studied at a momentum of 3.6 GeV/c in a hydrogen bubble chamber. Particular attention was paid to single and multiple pion production without annihilation. Cross sections for the various pion-production channels are given. The total cross section for pion production without annihilation and not including strange-particle production is 18.6−3.3+2.4 mb. Single pion production is found to agree with the predictions of the one-pion-exchange model for small values of the four-momentum transfer. Double pion production in the reaction p¯p→pp¯π+π− agrees with the one-pion-exchange model for all values of the four-momentum transfer, if all possible diagrams are taken into account. The main contribution comes from events where a 32−32 pion-nucleon isobar-anti-isobar pair is produced. For these events the Treiman-Yang angular distribution and the decay angular distributions of the isobars are also in agreement with the one-pion-exchange model.
No description provided.
No description provided.
Forum