Pre-requisite: You have to know your last commit message from your deleted branch.
git reflogSearch for message in the list:
a901eda HEAD@{18}: commit: <last commit message>
Now you have two options, either checkout revision or HEAD
git checkout a901eda
# or
git checkout HEAD@{18}Create branch
git branch recovered-branchYou may want to push that back to remote
git push origin recovered-branch:recovered-branch