Spin Density in a Polarised Liquid Xenon Target Compared with Solid-State Polarised Media

This paper examines what polarised spin density a liquid xenon target actually delivers once isotopic abundance and achievable polarisation are included, set against solid polarised media. The system considered is liquid xenon at 3 grams per cubic centimetre with xenon-129 enrichment and thirty percent polarisation, and the observable is isotopic, polarisation-corrected spin density and the comparison with solids. Evaluating the ordinary behaviour of the system and the spin-torsion contribution under explicit assumptions about polarisation and uniformity, and inverting the comparison at the stated laboratory precision, gives a quantitative bound rather than a qualitative assertion of smallness. The computed record is: total_density_per_m3 = 1.379e+28; xe129_density_per_m3 = 3.641e+27; polarised_spin_density_per_m3 = 1.092e+27; solid_reference_per_m3 = 3.000e+28; ratio_to_solid = 0.03641. The torsion-related contribution is far below the level that would alter the ordinary behaviour of the system at current precision, and the value that would have produced a visible residual is stated so that future improvements can be assessed against it directly. No new measurement is reported. This study is simulated and computed from stated assumptions, not measured.