Al-Husayn ibn Sa'id from Al-Hasan from his brother from Zur'ah from Sama'ah who said:
I asked Him about laughter, does it break the prayer? He said: "As for smiling, it does not break the prayer, but as for loud laughter, it does break the prayer."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 348