We have studied K+π− elastic scattering in the reaction K+p→K+π−Δ++ at 12 GeVc and in the Kπ mass interval 800 to 1000 MeV. We have performed a partial-wave analysis in this Kπ mass region, dominated by the p-wave resonance K*(890), in order to obtain information about the s-wave amplitude. We have extrapolated the K+π− moments, the total cross section, and p-wave cross section to the pion pole. The p-wave cross section is close to the unitarity limit and can be described by a Breit-Wigner resonance form, with parameters M=896±2 MeV and Γ=47±3 MeV. We then perform an energy-independent phase-shift analysis of the extrapolated moments and total cross section using this Breit-Wigner form for the p wave and a previously determined small negative phase shift for the I=32s wave. For the I=12s-wave phase shift we find the so called "down" solution, which has a phase shift that rises slowly from 20° at M(Kπ)=800 MeV to 60° at M(Kπ)=1000 MeV. The energy dependence of this phase shift is well described by an effective range form, with a scattering length a01=−0.33±0.05 F. The so-called "up" solution is eliminated or has large χ2 everywhere except for two overlapping mass intervals at M(Kπ)=890 and 900 MeV. However, due to limited statistics, we expect two solutions for the s wave very near the mass where the p wave is resonant. We then perform an energy-dependent partial-wave analysis and find again no evidence for an s-wave resonance although, due to limited statistics, we could not exclude one at 890 MeV with Γ<7 MeV.
Extrapolation.
Extrapolation. Initial K+ PI- system in P-wave state.
A partial-wave analysis of the (K ππ ) 0 system produced in the charge exchange reaction K − p →( K 0 π + π − ) n has been made in the mass range 1.04 ⩽ M (K ππ ) < 1.56 GeV c data at 8, 10 and 16 GeV/ c . It was found that in about 2 3 of the cases, the (K ππ ) 0 system is produced in states of unnatural spin-parity, namely J P = 0 − and 1 + ; the rest is in the natural spin-parity state J P = 2 + state is consistent with being all K ∗ (1420). The unnatural spin-parity states are produced mostly (∼ 80% of the events) by natural parity exchange. The facts that unnatural spin-parity states are produced in this non-diffractive channel, with J P = 1 + dominant, and that the exchange responsible for their production is mostly of natural parity, are similar to what was found for the charged (K ππ ) − system in the diffractive reaction K − p→(K ππ ) − p. However, the absolute value and the energy dependence of the cross sections are very different in the two cases.
CORRECTED FOR UNSEEN AK0 DECAY MODES.
ACTUALLY CROSS SECTIONS FOR PRODUCTION IN MASS REGION 1.04 < M(AK0 PI+ PI-) < 1.56 GEV IN THE STATES JP = 1+, 2+ AND 0- RESPECTIVELY.
The process pn → pp π − is studied in pd collisions at 11.6 GeV/ c . A broad low-mass enhancement of p π − is found in the diffractive reaction pn → p(p π − ) with a cross section slightly smaller than that of a similar analysis at 7.0 GeV/ c . The non-diffractive reaction pn → (p π − )p shows some evidence for resonance production and its cross-section dependence on energy is characteristic of meson exchange. Samples of mass, momentum transfer, and decay angular distributions are compared with the predictions of a double Regge model and a reggeized one-pion exchange model. Using in addition information from the reactions pp → pp π 0 , pp → pn π + at 12.0 GeV/ c , an isospin analysis of the single pion production reaction from nucleon-nucleon scattering, N 1 N 2 → N 3 (N 4 π ) is presented.
NON-DIFFRACTIVE CHARGE-EXCHANGE CROSS SECTIONS.
The average charged particle multiplicity, 〈 n ch ( M X 2 )〉, in the reaction K + p→K o X ++ is studied as a function of the mass squared, M X 2 , of the recoil system X and also as a function of the K o transverse momentum, p T , at incident momenta of 5.0, 8.2 and 16.0 GeV/ c . The complete data samples yield distributions which are not independent of c.m. energy squared, s , They exhibit a linear dependence on log ( M X 2 X / M o 2 )[ M o 2 =1 GeV 2 ] with a change in slope occurring for M X 2 ≈ s /2, and do not agree with the corresponding distributions of 〈 n ch 〉 as a function of s for K + p inelastic scattering. Sub-samples of the data for which K o production via beam fragmentation, central production and target fragmentation are expected to be the dominant mechanisms show that, within error, the distribution of 〈 n ch ( M X 2 )〉 versus M X 2 is independent of incident momentum for each sub-sample separately. In particular in the beam fragmentation region the 〈 n ch ( M X 2 )〉 versus M X 2 distribution agrees rather well with that of 〈 n ch 〉 versus s for inelastic K + p interactions. The latter result agrees with recent results on the reactions pp → pX and π − p → pX in the NAL energy range. Evidence is presented for the presence of different production mechanisms in these separate regions.
Two parametrizations are used for fitting of the mean multiplicity of the charged particles : MULT = CONST(C=A) + CONST(C=B)*LOG(M(P=4 5)**2/GEV**2) and MULT = CONST(C=ALPHA)**(M(P=4 5)**2/GEV**2)**POWER.
We present results of measurements of the n−p total cross section between 30 and 280 GeV/c. The measurements were carried out with a neutron beam by using the standard transmission technique and a liquid-hydrogen target. A total-absorption calorimeter was used to determine the neutron energy. Our measurements, which have an accuracy of ∼1%, indicate a smooth rise of approximately 1.5 mb between 50 and 280 GeV/c. The combined n−p and p−p data above 20 GeV/c are well fitted by the expression σ=38.4+0.85|ln(s95)|1.47 mb.
MOST DATA TAKEN WITH 300 GEV/C INCIDENT PROTONS TO PRODUCE THE NEUTRON BEAM, WITH SOME ALSO USING 200 GEV/C PROTONS.
In a 35 000-picture exposure of the 30-in. hydrogen bubble chamber to a 300-GeV/c proton beam at the Fermi National Accelerator Laboratory, 10054 interactions have been observed. The measured total cross section is $40.68 \pm 0.55$ mb, the elastic cross section is $7.89 \pm 0.52$ mb, and the average charged-particle multiplicity for inelastic events is $8.S0 \pm 0.12$.
QUOTED ERRORS INCLUDE EFFECTS OF CORRECTIONS.
No description provided.
We have observed 1085 events of the type e + e − → hadrons, in the total centre-of-mass energy range √ s = 1.2 to 3.0 GeV. The energy dependence of the total annihilation cross-section, parametrized in the form σ ( e + e − → hadrons ) = A · s n , is measured to be n = -(1.54 −0.29 +0.17 ) in the above energy range.
RESULTS USING THE (AP P) MODEL WITH PHASE-SPACE CORRECTIONS.
R AS CALCULATED FROM THE TOTAL HADRONIC CROSS SECTION USING THE (AP P) MODEL.
TOTAL CROSS SECTIONS OBTAINED USING THE QUASI-MODEL-INDEPENDENT METHOD ARE TABULATED HERE.
We have measured deep inelastic muon-deuteron scattering in the range 0.4<Q2<3.4 and 1.6<ν<5.6 GeV. We have extracted the neutron structure function and find that νW2n differs significantly from νW2p, as also found in e−d scattering. To compare μ−d and e−d scattering we form the ratio r(Q2)=(νW2)μd(νW2)ed=N(1+Q2Λ2)−2 and find N=0.925±0.038 and 1Λ2=−0.019±0.016.
No description provided.
We have measured the crosss section for the reaction e + e − → 4 π ± in the energy range 1 2–3.0 GeV.No statistically significant evidence for a new vector meson in the ϱ″ region is found.
No description provided.
None
X ERROR D(EKIN) = 0.0600 MEV.
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