It may well not exist. Wouldn't be the first time the West straight up made up what China allegedly "said but then quickly censored." Like, I can't think of an obvious reason to delete an article like this.

Maybe if it's suspected to cause civil unrest, and they want to avoid that? Existence of extraterrestrial life is big news, and possibly disturbing and scary news to many. But in that case, why release the article in the first place? In English no less, would likely have involved a dedicated English language writer or translator, which would be a pretty conscious action on the part of the Chinese speaking press.

Also, wouldn't there be a proper scientific paper of the findings and not just an article if they did intend to publish it? I mean, maybe there is, and it's in Chinese, but mainstream layman's news coverage quoting a different mainstream layman's publication is definitely a red flag for the actual research not exiting.