12C(e,e'pN) measurements of short range correlations in the tensor-to-scalar interaction transition region

The CLAS Collaboration

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High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the 12C(e,ep) and 12C(e,epN) reactions (where N is either n or p), at high-Q2 and xB>1.1. The data span a missing-momentum range of 300–1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon (NN) interaction models. This agreement suggests that the measured high missing-momentum protons up to 1000 MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured 12C(e,epN) / 12C(e,ep) and 12C(e,epp) / 12C(e,epn) cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor NN interaction at ∼400 MeV/c to an isospin-independent scalar interaction at high-momentum around ∼800 MeV/c as predicted by theoretical calculation.

Original languageEnglish
Article number136523
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Early online date2 Aug 2021
Publication statusPublished - 10 Sept 2021

Bibliographical note

Funding Information:
We acknowledge the efforts of the staff of the Accelerator and Physics Divisions at Jefferson Lab that made this experiment possible. The analysis presented here was carried out as part of the Jefferson Lab Hall B Data-Mining project supported by the U.S. Department of Energy (DOE). The research was also supported by the National Science Foundation , the PAZY Foundation , the Israel Science Foundation and the United Kingdom's Science and Technology Facilities Council (STFC). The Jefferson Science Associates operates the Thomas Jefferson National Accelerator Facility for the DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177 .

Publisher Copyright:
© 2021 The Author(s)

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