# Lattice QCD Method To Study Proton Radius Puzzle

## TL;DR

This paper develops a lattice QCD approach to calculate the proton's charge radius from first principles, aiming to address the proton radius puzzle caused by experimental discrepancies.

## Contribution

It formulates a non-perturbative lattice QCD method to compute the proton charge radius directly from QCD, providing a new tool for resolving experimental disagreements.

## Key findings

- Derived a non-perturbative formula for proton charge radius
- Established a lattice QCD framework for the proton radius
- Provides a first-principles calculation method

## Abstract

Recently there has been disagreement between various experiments about the value of the proton radius which is known as the proton radius puzzle. Since the proton is not a point particle the charge radius of the proton depends on the charge distribution (the form factor) of the partons inside the proton. Since this form factor is a non-perturbative quantity in QCD it cannot be calculated by using the perturbative QCD (pQCD) method but it can be calculated by using the lattice QCD method. In this paper we formulate the lattice QCD method to study the charge radius of the proton. We derive the non-perturbative formula of the charge radius of the proton from the first principle in QCD which can be calculated by using the lattice QCD method.