For many months now, U.S. and European intelligence agencies have been trading theories about a spare, two-page document written in Persian that, if genuine, would strongly suggest that scientists in Iran were planning some of the final experiments needed to perfect an atom bomb.

But like so many pieces of evidence in the West’s confrontation with Tehran, the neatly written memorandum, laying out the next steps of a complex scientific process, raises as many questions as it answers.

Intelligence officials say they have yet to authenticate the document, which describes research Iran would need to conduct on an advanced technology to detonate a nuclear weapon, if it was to develop one. Even if the paper is genuine, they say, it is unclear if it provides new insights into the state of Iran’s weapons research.

Diplomats raised the possibility that the publication of the memo on The Times of London Web site late Sunday could be part of an effort to raise international alarm over Iran’s intentions or progress in developing nuclear weapons capacity.

The document describes a plan for measuring the output of a device called a neutron initiator, which has no use other than triggering a nuclear explosion. Intelligence agencies are treating it as if the very paper it was written on was itself radioactive.

The CIA has not declared whether it believes the document is real, according to intelligence officials from several countries. European spy agencies are similarly cautious.

Inside intelligence agencies, the document has attracted much attention because its subject matter is familiar to anyone who has delved into Iran’s atomic experiments: It describes a testing regime that would help Iran master the science of the initiator, a device to generate bursts of subatomic particles known as neutrons, which initiate and speed the chain reactions that lead to the detonation of a warhead.