@article{130247ec44c545a0a5b5fabc169a6f3e,
title = "Beam helicity asymmetries in K+Λ electroproduction off the proton at low Q2 ",
abstract = "Beam helicity asymmetries in the e→ p→ eK+Λ reaction have been measured at unprecedentedly low four-momentum transfers 〈 Q2〉 = 0. 05 (GeV/c)2. At the Mainz Microtron (MAMI), the experiment was performed with a longitudinally polarized beam and an out-of-plane detection of the scattered electron. This experiment probed the associated helicity-dependent structure function dσLT/dΩKc.m., which is sensitive to the details of resonances of the proton. The results were compared to models for kaon electroproduction using effective Lagrangians. The MAMI data is not supporting the Kaon-Maid isobar model, which uses strong longitudinal couplings of the virtual photon to nucleon resonances and predicts a strong peaking of the structure function at forward angles and low Q2. The data is also in disagreement with a Regge-plus-resonance model that predicts the incorrect sign of the structure function. The combination of the MAMI results wih data taken at higher four-momentum transfers measured at Jefferson Lab indicates a smooth transition in Q2 without significant changes of the interference pattern in the electroproduction process.",
author = "{A1 Collaboration} and P. Achenbach and {Ayerbe Gayoso}, C. and R. B{\"o}hm and O. Borodina and D. Bosnar and V. Bozkurt and P. Byd{\v z}ovsk{\'y} and L. Debenjak and Distler, {M. O.} and A. Esser and I. Fri{\v s}{\v c}i{\'c} and Y. Fujii and T. Gogami and {G{\'o}mez Rodr{\'i}guez}, M. and O. Hashimoto and S. Hirose and H. Kanda and M. Kaneta and E. Kim and A. Margaryan and H. Merkel and U. M{\"u}ller and S. Nagao and Nakamura, {S. N.} and J. Pochodzalla and C. Rappold and J. Reinhold and Saito, {T. R.} and {Sanchez Lorente}, A. and {S{\'a}nchez Majos}, S. and Schlimme, {B. S.} and M. Schoth and F. Schulz and C. Sfienti and S. {\v S}irca and D. Skoupil and L. Tang and M. Thiel and K. Tsukada",
note = "Funding Information: We acknowledge the MAMI accelerator group for their outstanding support. This work was supported in part by Deutsche Forschungsgemeinschaft (SFB 1044), the Carl Zeiss Foundation, European Community Research Infrastructure Integrating Activity FP7, by U.S.-DOE Contract No. DEFG02-97ER41047, the Strategic Young Researchers Overseas Visits Program for Accelerating Brain Circulation (R2201), and the Core-to-Core program (21002) of JSPS. PB and DS acknowledge support of the Grant Agency of the Czech Republic under Grant No. P203/15/04301.",
year = "2017",
month = oct,
day = "1",
doi = "10.1140/epja/i2017-12395-1",
language = "English",
volume = "53",
journal = "European Physical Journal A",
issn = "1434-6001",
number = "10",
}