I would like to find posterior with jeffreys'

I am a new stan user and trying to find the posterior of Jeffreys’ prior.
This is my model.
data {
int<lower=0> n; // obs in group x
real x[n];
parameters {
real muX;
real<lower=0> sigmaX;
model {
x ~ normal(muX, sigmaX);
generated quantities {
real postPred;
postPred <- normal_rng(muX, sigmaX);

I followed “https://stats.stackexchange.com/questions/156721/define-own-noninformative-prior-in-stan”.
My data also include 0.
How can I add the other parameters in this model?

Hi, I am sorry, but I do not understand your question. What “other parameters” you have in mind? What problem are you trying to model? What is the scientific question that underlies the model you are trying to build? Are you trying to solve a practical problem or trying to do an excercise to help you better understand Stan?