Measurement of the unpolarized kaon(+)Lambda and kaon(+)Sigma(0) electroproduction cross sections and interference terms from the proton with the CLAS detector.

摘要

Using the CLAS detector, we measure the K+Λ and K+Σ0 electroproduction response functions over the continuous kinematic range from threshold to W = 2.05 GeV and for Q2 between 0.5 and 1.5 (GeV/c)2, with nearly complete angular coverage in the center-of-momentum frame angles. The σ_T + &epsis;σ_L, σ_TT and σ_LT terms are extracted and compared to recent theoretical calculations based upon a hadrodynamic effective-Lagrangian framework. From examining the W-dependence of the response functions for the K+Λ final state, we find features in the (σ_T + εσ _L) term in the W = 1.75 to 1.90 GeV region, similar to features seen in recent photoproduction results. In general, the σ _TT and σ_LT response-functions for Λ production are of the same order of magnitude as the (σ _T + εσ_L) term, suggesting that both σ_T and σ_L contribute significantly. For the K+Σ 0 final state the W-dependence of the (σ _T + εσ_L) and σ _TT terms have large, resonant-like features near W = 1.9 GeV. Unlike in Λ electroproduction, the σ _LT interference term for Σ0 electroproduction is found to be consistent with zero across nearly the entire kinematic range, while σ_TT is comparable in magnitude to the σ_T + εσ_L differential cross-section. The models, while achieving some qualitative agreement with the data, fail to both describe the details of the angular distributions and reproduce the resonant-like behavior observed.