I believe you're referring to the Chung's probability theorem, also known as Chung's lemma. However, I think you might be looking for the Chung-Fuchs theorem or more specifically, the probability density function (pdf) related to Chung's work.
If you provide more information or clarify which Chung probability distribution or theorem (e.g., Chung-Fuchs, Chung-Lai, or Chung-Sobel) you are referring to, I may provide you a more accurate response and high-quality equations. chung probability pdf
Let $X$ be a random variable. Assume that I believe you're referring to the Chung's probability
References: Chung, K. L., & Fuchs, W. H. J. (1946). On the law of the iterated logarithm. Proceedings of the American Mathematical Society, 2(5), 312-319. Let $X$ be a random variable
Assuming you're referring to the Chung's theorem related to the law of the iterated logarithm, I provide you with a brief overview.
Here, I couldn't find or assume well known standard Chung distribution.
In 1946, Chung and Fuchs proved a theorem that provides a sufficient condition for the law of the iterated logarithm (LIL) to hold.