16th International Conference on Muon Spin Rotation, Relaxation and Resonance (μSR2025)

Improving Accuracy of Muonic X-ray Transition Simulations: New Nuclear Models for MuDirac

Not scheduled

20m

Poster Presentation Chemistry Poster session 2

Speaker

Philip Jones (School of Engineering, University of Warwick, UK.)

Description

The value of the nuclear charge radius depends on features of the nuclear structure such as the nuclear charge distribution, ρ, which has been systematically measured for almost all stable nuclei.

The nuclear charge radius can be mathematically defined using ρ, which in turn can be deduced from the X-ray transition energies of a muonic atom. The binding energy of the muonic atom is sensitive to ρ and, in principle, the problem of determining the nuclear charge radius using ρ and muonic X-ray measurements can be tackled.

One way of treating this problem is assuming a functional form for ρ, such as the 2-parameter Fermi distribution (2pF), which assumes that the nucleus has a homogeneously charged spherical core with radius c, and a skin of thickness t along which the charge exponentially decreases.

The current version of MuDirac uses an implementation of the 2pF, for defining the potential in the Dirac equation, where the values of c are taken from tables and the value of t is set at 2.3x10$^{-15}$m.

In this poster, we will present the work that we have been doing to implement a more accurate version of the 2pF model in MuDirac, where c and t are variables that are defined for every specific muonic atom using a combination of computational modelling and experimental results. This method allows for a more accurate estimation of the muonic X-ray transition energies, the nuclear charge distribution, ρ, and the nuclear charge radius.