We have analyzed 2560 events in the final-state K O 1 K O 1 n produced in π − p interactions at 5, 7 and 12 GeV/ c . We observe the S ∗ (1070), f O and A 2 decaying into K O 1 K O 1 . Resonance parameters, cross sections, and branching ratios are given.
Cross section times branching ratio.
An analysis of the reaction K−p→K−pπ+π− at 2.0-GeVc incident momentum is presented. The total cross section for the reaction is 627±20 μb, based on 4519 events. The reaction is dominated by resonance production through several channels which overlap kinematically but do not appear to interferesubstantially. A maximum-likelihood procedure was used to determine the production fractions, which for the major channels are 0.44±0.02 for N*++(1236), 0.145±0.02 for Y*0(1520), 0.10±0.03 for N*+(1688), and 0.20±0.02 for simultaneous K¯*0N*0. Evidence is presented for the production of Y*+(1765) and its decay into Y*0(1520) as well as for production of Y*+(1660) with decay into K−pπ+. A four-standard-deviation enhancement is present at a K−π+ invariant mass of 690 MeV. Angular correlation data are presented for the N*++K−π−, Y*0π+π−, and K¯*0N*0 reaction channels. However, the difficulty of separating the various channels prevents a detailed study of the reaction dynamics.
No description provided.
None
'1'. '2'. '3'.
Over 100 unambiguous π − + p → Λ + Λ + n events have been observed in a magnet spark chamber. The data provide good evidence for peripheral production of Λ Λ and n Λ (via meson exchange) and against peripheral n Λ (double baryon exchange). No resonances in the Λ Λ system are observed. Angular distributions and Λ( Λ ) polarizations are analysed.
Axis error includes +- 0.0/0.0 contribution (?////Corrected for neutral decays, absorption).
We have studied the reaction e−+p→e−+π++n by detecting the final electron and pion in coincidence. Data are presented in the region of virtual photon mass squared from -0.18 to -1.2 GeV2, and virtual photoproduction center-of-mass energy and angle from 1.85 to 2.50 GeV and 0 to 20°, respectively.
No description provided.
No description provided.
No description provided.
From analysis of V0 events observed in an exposure of the National Accelerator Laboratory 30-in. bubble chamber to 303−GeVc protons, we obtain these results: (1) 〈nπ0〉 rises approximately linearly with n-, implying strong coupling of neutral and charged pions, while 〈nKS0〉 is less coupled to n; (2) γ, KS0, and Λ0 production cross sections are approaching a scaling limit by 303 GeVc; (3) within the limited statistics, dσdy is flat in the central region for KS0 and low-multiplicity γ events.
No description provided.
Total cross sections have been measured for the transmission of long-lived neutral K mesons through hydrogen and deuterium. The momentum range for the KL0 was 130-550 MeV/c. The momentum of each detected kaon was measured by time of flight. The cross sections are consistent with earlier less precise results. Comparison of the KL0 cross sections is made with the results of several K-matrix fits to other K¯N data, and the KL0 total cross sections are compared with existing theoretical calculations for K−d total cross sections.
THE AUTHORS ADVISE AGAINST USING THESE CROSS SECTIONS WHEN COMBINING THEM WITH OTHER DATA SETS. IT IS RECOMMENDED THAT ONE SHOULD USE INSTEAD THE ORIGINAL DATA POINTS FOR SINGLE-CHOPPED AND DOUBLE-CHOPPED INJECTION (WHICH HAVE SEPARATE NORMALIZATION ERRORS) FROM WHICH THESE COMBINED DATA ARE DERIVED. A NORMALIZATION ERROR FOR THESE AVERAGED CROSS SECTIONS IS THEREFORE NOT QUOTED.
The amplitude and phase for coherent regeneration in hydrogen and deuterium have been measured for six momentum bins in the range 3.5-10.5 GeV/c. Over this region the phase, ϕf, is consistent with being constant and has the value - 60°±8° for hydrogen and - 46°±8° for deuterium. Power-law fits of the form plabn for the amplitudes when combined with other data give n=−0.60±0.02 for hydrogen and n=−0.52±0.02 for deuterium.
No description provided.
NOTE PHASE IS HERE DEFINED AS THE PHASE OF I*AMP(NAME=REGEN) AND SO DIFFERS BY 90 DEG FROM USUAL DEFINITION.
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.
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.
Forum