Measurement of the Nucleon F_{2}^{n}/F_{2}^{p} Structure Function Ratio by the Jefferson Lab MARATHON...

Area of Science:

• Nuclear Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The nucleon F2 structure functions (F2n/F2p) are crucial for understanding the internal structure of protons and neutrons.
• Previous measurements of the F2n/F2p ratio have significant uncertainties, limiting precise tests of Quantum Chromodynamics (QCD) and nuclear models.

Purpose of the Study:

• To precisely determine the ratio of the nucleon F2 structure functions, F2n/F2p, using deep inelastic electron scattering.
• To leverage the mirror symmetry of tritium (3H) and helium-3 (3He) nuclei to minimize theoretical uncertainties in the ratio extraction.

Main Methods:

• The MARATHON experiment utilized deep inelastic scattering of electrons off 3H and 3He targets at Jefferson Lab.
• High-resolution spectrometers and a specialized cryogenic target system were employed for precise measurements.
• A novel data analysis technique exploiting nuclear mirror symmetry was developed to extract the F2n/F2p ratio.

Main Results:

• The F2n/F2p ratio was measured across a wide range of the Bjorken scaling variable x (0.19 < x < 0.83).
• The results show significant improvements in precision compared to previous measurements from SLAC and Jefferson Lab.
• The obtained ratio data provides a stringent test for theoretical calculations and empirical determinations.

Conclusions:

• The MARATHON experiment provides the most precise determination to date of the F2n/F2p ratio.
• These findings offer valuable insights into nucleon structure and the effects of nuclear matter on parton distribution functions.
• The improved data will facilitate more rigorous comparisons with theoretical predictions in nuclear and particle physics.