We present differential cross-sections for the electro-production of single charged pions from deuterium for a virtual photon mass squared −1.0 GeV2 and for pion nucleon masses in the range 1.23–1.68 GeV (the 1st and 2nd resonance regions). The data are compared with predictions from fits to hydrogen data.
FORWARD BINS.
No description provided.
No description provided.
None
DEDUCED FROM MEASUREMENTS AT EPSILON OF 0.20 AND 0.65.
The ratio of π − to π + electroproduction cross sections from deuterons has been measured in the resonance region at an average four-momentum transfer squared of 0.5 (GeV/ c ) 2 . Results are presented over a wide range of pion production angles and comparisons are made with theoretical predictions based on SU(6) w symmetry and the Melosh transformation.
No description provided.
No description provided.
No description provided.
The reactionsΣvp→π+n,K+Λ,K+∑0 andΣvn→π+n were studied at invariant hadronic masses around 2.2. GeV forQ2=0.06, 0.28, 0.70, and 1.35 GeV2. The main results are: At small |t| the π+ production is dominated by longitudinally polarized photons and can be described by one pion exchange. At low |t| the transverse (π+n) cross section drops steeply withQ2, but remains roughly constant forQ2≧0.5 GeV2. For |t⊢≧0.8 GeV2, (π+n/dt) is almost independent ofQ2. The integrated cross section (π+n) shows a similarQ2-dependence asσtot (γvp) forQ2≧0.28 GeV2. The ratioσ(π-p)/σ(π+n) atQ2=0.70 and 1.35 GeV2 for |t|≧0.6 GeV2 is smaller than in photoproduction and close to 1/4. The ratioσ(K+∑0 decreases steeply withQ2 following roughly the predictions of the quark-parton model.
PHI AND EPSILON DEPENDENCE FITTED TO GIVE COMPONENTS OF CROSS SECTION.
No description provided.
No description provided.
The ratio of π - to π + electroproduction cross sections from deuterium has been measured in the resonance region, at a four-momentum transfer squared close to −1.0 (GeV/ c ) 2 . Results in the forward direction are presented and a comparison is made with predictions based on SU(6) W and the Melosh transformation.
No description provided.
The rates for forward electroproduction of single charged pions from deutrium have been measured in the resonance region, at a virtual photon mass squared ≈−0.5( GeV/ c 2 ) 2 . Results are presented in the form of a π − to π + cross-section ratio.
No description provided.
We report on an experiment where the different contributions from the transverse and longitudinal polarization of the virtual photon are measured separately for the reaction e − p→e − π + n. The data taken above the resonance region at small ∣ t ∣ values in the q 2 range of ∣ q 2 ∣ < 0.5 GeV 2 show a clear dominance of the longitudinal part of the cross section and are well described by a generalized Born-term model. Using this model the electromagnetic form factor of the pion is determined. At q 2 = −0.35 GeV 2 one gets F π = 0.598 ± 0.021.
No description provided.
AVERAGED OVER RESTRICTED PHI RANGE. THIS IS MAINLY (D(SIG(NAME=U))/DT + EPS*D(SIG(NAME=L))/DT) SINCE COMPONENTS P AND I ARE EXPECTED TO REMAIN SMALL FOR LARGER -T.
No description provided.
We report measurements of the exclusive electroproduction reaction e+p→e+π++n for pions produced near 0° in the virtual-photon-proton center-of-mass system with values of ε in the range 0.35<ε<0.45. Combination with data taken at ε near 1 allows us to separate the contributions from transversely polarized and scalar photons in the range 1.2 GeV2<Q2<3.3 GeV2.
No description provided.
No description provided.
No description provided.
The four cross section components σ U , σ L , σ P and σ I were separated in the reaction γ V + p → π + + n at an electron four momentum transfer of Q 2 = 0.70 GeV 2 and an invariant hadronic mass of 2.19 GeV in the range of t between t min and −0.28 GeV 2 . The longitudinal cross section σ L dominates at small |t| and decreases rapidly with increasing |t|. The data are in rough agreement with the prediction of a generalized Born term model. The resulting value for the pion electromagnetic form factor is F π = 0.42 ± 0.015.
TMIN = 0.024 GEV**2.
No description provided.
The reaction e + p → e' + n + π + was studied detecting e' and e' and π + in coincidence at an invariant hadronic mass of 2.19 GeV. The measurements were performed at electron four-momentum transfers squared of Q 2 = 0.06, 0.28, 0.70, and 1.35 GeV 2 in the range of t = ( γ v − π ) 2 between t min and −1.0 GeV 2 . The cross section d 2 σ / dtd was found to be roughly independent of Q 2 for Q 2 > 0.7 GeV 2 and ∥ t ∥ > 0.2 GeV 2 .
No description provided.
No description provided.
No description provided.