We measured the cross section for proton-proton elastic scattering at 11.75 GeV/c using the Zero Gradient Synchrotron 52% polarized proton beam and a 60% polarized proton target. We measured dσdt(ij) in the ↑↑, ↓↓, and ↑↓ initial spin states perpendicular to the scattering plane in the range P⊥2=2.0−3.6 (GeV/c)2. We found that the asymmetry parameter A decreases smoothly with increasing P⊥2 in this range, and that the spin-spin correlation parameter Cnn may have a minimum near P⊥2=3 (GeV/c)2.
No description provided.
We present experimental evidence for a resonant behaviour of the hadron production from e + e − annihilations at the e + e − storage ring ADONE. A Breit-Wigner fit to the enhancement present between 1800 and 1850 MeV gives the following parameters M = 1812 −13 +7 MeV, Γ = 34 −15 +21 MeV.
MULTIHADRON EVENTS (AT LEAST THREE CHARGED TRACKS) PER UNIT LUMINOSITY.
Multihadron production has been measured at the Adone e + e − storage ring in the c.m. energy region 1600 ÷ 1900 MeV. A resonant behaviour is observed, centered at 1819 ± 5 (±2) MeV, with a width of 24 ± 5 (±4) MeV. This effect is observed only in the events with 3 or 4 charged particles together with photons, but not in those without photons.
MULTIHADRON EVENTS (3 OR 4 CHARGED PARTICLES PLUS ONE OR MORE PHOTONS DETECTED) PER UNIT LUMINOSITY. RESONANCE NOT SEEN IN EVENTS WITH NO PHOTONS.
We present experimental results on a number of K − p reactions at 14.3 GeV/ c that have three bodies in the final state. The final states are K − ω p , K − π p , Λπ + π − , Λ K + K − , Λp p , K ∗ − ω p , Λ(1520) K + K − and Λ(1520) p p . Whenever, with one exception explained by the Zweig rule, there is a K − or a proton in the final state, there is a diffractive-like threshold enhancement in the mass spectrum of the two recoiling particles. These enhancements account for a large fraction of the events in all but the Λπ + π − final state, where they cannot occur, and which is dominated by resonance production. We find evidence for the Q 1 (1300) decaying into K − ω .
THE DIFFRACTION DISSOCIATION CROSS SECTIONS ARE FOR DIFFRACTIVE THRESHOLD ENHANCEMENTS IN THE TWO-BODY MASS SPECTRA (WITHIN 500 MEV CM ENERGY OF THRESHOLD).
Results are presented concerning K − d and K − n elastic scattering at an incident momentum of 4.5 GeV/ c . The high-energy Glauber formalism has been used in analyzing the data in which the nucleon scattering amplitudes are parameterized and employing the spherical and quadrupole deuteron form factors. An impulse approximation analysis of the K − n differential scattering cross section fitted to a single exponential of the form d σ /d t ) 0 e Bt , leads to the result (d σ /d t ) 0 = 21.3 + mn ; 5.5 mb/(GeV/ c ) 2 and B = 6.9 + mn ; 0.5 (GeV/ c ) −2 . A global fit has been made to existing K + mn; N two-body scattering data at this energy in order to determine the scattering amplitudes. It was found that the K − n and K − p elastic amplitudes are dominantly imaginary with a relatively small contribution from spin-flip amplitudes. The slopes of the differential elastic cross sections for K − n and K − p are nearly equal, as are those for K + n and K + p. However, the value of the slope for K + is smaller than that for K − at this energy.
No description provided.
No description provided.
No description provided.
The production of enutral kaons in e + e − annihilation has been measured for c.m. energies between 3.4 GeV and 7.6 GeV. Near 4 GeV the inclusive K S cross section shows an increase and structure similar to total hadron production. Roughly 40–45% of all hadronic final states contain kaons, except at 4.028 GeV and 4.415 GeV, where a significantly larger kaon fraction is observed.
No description provided.
THIS IS TWICE THE MEASURED KS CROSS SECTION. THE ERRORS ARE STATISTICAL ONLY. THERE IS 15 PCT ABSOLUTE NORMALIZATION ERROR, PLUS POSSIBLY SOME ENERGY DEPENDENT ERROR. THE DATA ARE NOT EQUALLY SPACED IN THE ENERGY INTERVALS.
The multiplicity distribution of inclusive electron events above 4 GeV cm energy shows two distinct classes of events: two prong no photon and high multiplicity events. If the high multiplicity events are attributed to the semi-leptonic decay of charmed particles the two prong no photon events must come from the weak decay of a different type of particle. The charged K to π ratio was measured for these events. The average number of charged kaons is 0.07 ± 0.06 per two prong event and 0.90 ± 0.18 per multiprong event. Thus the weak current responsible for the low multiplicity events has a small coupling to strange particles.
NUMBER OF CHARGED PARTICLES OBSERVED .EQ. 2.
NUMBER OF CHARGED PARTICLES OBSERVED .GE. 3.
We report on a study of the charge-exchange reaction pp → nΔ ++ (1232) at the CERN intersecting storage rings (ISR) in the energy range √ s = 23 to 53 GeV. From our analysis of the energy dependence of the total cross-section, of the differential cross-section d σ /d t and of the decay angular distributions we find evidence that pion exchange is dominant up to √ s = 23 GeV and that ( ϱ +A 2 ) exchange dominates the reaction for √ s ⩾ 30 GeV, as described by simple Regge-pole models.
THE ERRORS ARE DUE TO STATISTICAL ERRORS AND BACKGROUND SUBTRACTION ERRORS COMBINED IN QUADRATURE.
THE ERRORS ARE DUE TO STATISTICAL ERRORS AND BACKGROUND SUBTRACTION ERRORS COMBINED IN QUADRATURE.
No description provided.
The general features of p p interactions at 32 GeV/ c are analysed in a bubble chamber experiment with a statistics of 5.2 μb/event. The inclusive production of neutral strange particles and pions is analysed and compared to results obtained at other energies and in pp interactions. Total cross sections are determined for various 4C reactions and the relative contributions of diffractive dissociation and Δ Δ production to the reaction p p → p p π + π − are estimated.
No description provided.
TOTAL CROSS SECTIONS FOR 4C REACTIONS.
The reactions K − d→ Σ − p, K − d→ Σ − (1385)p, K − d→ Λ (1405)n and K − d→ Λ (1520)n have been studied at K − momenta between 686 and 844 MeV/ c in an experiment with the 81 cm Saclay bubble chamber at CERN. About 630 000 pictures have been analyzed. Partial and differential cross sections are presented. A one-nucleon-exchange model is used to extract the kaon-nucleon-hyperon coupling constants from these results. For g( K N Σ(1197)), g( K N Σ(1385)) and g( K N Λ(1405)) we find values which are compatible with the SU(3) predictions. The coupling constant g( K N Λ(1520)) obtained by our method agrees with that determined from the partial decay width for Λ(1520)→ K N .
CROSS SECTIONS FROM FITTING WITH BREIT-WIGNER DISTRIBUTIONS AND SMOOTH BACKGROUND.
CROSS SECTION WITH A T-CUT.
CROSS SECTION WITH A T-CUT.
Forum