First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

Abstract

We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high z and an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high z. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons.

Metadata

Funding Information: The authors would like to thank K. Gallmeister and U. Mosel for the fruitful discussions on the GiBUU model predictions for this production channel. We acknowledge the staff of the Accelerator and Physics Divisions at the Thomas Jefferson National Accelerator Facility who made this experiment possible. This work was supported in part by the U.S. Department of Energy Award No. DE-FG02-07ER41528, the Physics and Astronomy Department and the Office of Research and Economic Development at Mississippi State University, the Chilean Agencia Nacional de Investigacion y Desarrollo (ANID), including by ANID PIA/APOYO AFB180002, ANID PIA ACT1413, and ANID—Millennium Program—ICN2019_044, the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, by the Italian Istituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique, the French Commissariat á l’Energie Atomique, the United Kingdom Science and Technology Facilities Council (STFC), the Scottish Universities Physics Alliance (SUPA), the National Research Foundation of Korea, and the U.S. National Science Foundation. The Southeastern Universities Research Association operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy under Contract No. DE-AC05-06OR23177. Publisher Copyright: © 2023 American Physical Society. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

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