Electroweak form factors of large nuclei as BPS skyrmions

Abstract

We employ the Bogomolnyi-Prasad-Sommerfield (BPS) Skyrme model within the framework of semi-classical quantization to compute both electromagnetic and neutral current form factors for heavy nuclei. Our results show excellent agreement with the experimental data for low- to moderate momentum transfer. Further, we present an analytic expression of the neutral current form factor for generic nuclei, expressed as a power series in the momentum transfer. Our method provides an alternative to existing phenomenological approaches, and is particularly relevant for precision neutrino experiments where control over model-dependent systematics is essential for probing physics beyond the Standard Model.

Figures (3)

• Figure 1: Electromagnetic form factors for different nuclei. Solid lines represent the prediction of the BPS model, while the crosses correspond to the experimental parametrization of DeVries:1987atn.
• Figure 2: Neutral current form factors for $^{208}\rm Pb$ and $^{48}\rm Ca$. Solid lines represent the BPS model prediction, while dotted black/grey lines correspond to the Taylor series \ref{['ec:taylor']} for $^{208}\rm Pb$ and $^{48}\rm Ca$, respectively, up to $n=10$. Finally, dashed lines represent the KN model prediction. Experimental results are obtained from Horowitz:2012tjPREX:2021umoCREX:2022kgg.
• Figure 3: Nuclear mass and charge radius experimental data of the nuclei used to fit the parameters and their predicted values using the BPS Skyrme model with the fitting of \ref{['ec:lambdamu']}.