Their suggestion, commissioned by Labour, the Conservatives, and the Lib Dems, is: "Should Scotland become an independent state?”
Voters would then be able to tick one of two boxes, indicating either "I agree" or "I do not agree".
The Scottish Government has previously suggested that the question should be: "Do you agree that Scotland should be an independent country?" but some critics have complained that is inherently loaded, with the element of "Do you agree..."
First Minister Alex Salmond has also indicated that he would be happy to see a second question on the ballot paper if Scots indicate in advance they would be in favour of some form of "devo max".
However, Prime Minister David Cameron has insisted there should be only question.
Today's latest suggested wording was drawn up by:
Lord Sutherland, former principal of Edinburgh University and the architect of Scotland's free personal care for the elderly programme;
Dr Matt Qvortrup, a referendum expert and senior lecturer in comparative politics at Cranfield University;
Ron Gould, former assistant chief electoral officer of Canada and a veteran of over 80 elections in 50 countries who produced the critical report on the 2007 Scottish election.
Lord Sutherland said the question his group had put forward was "short, clear, understandable, and decisive".
He added: "It's a short question. We tried to avoid many of the complications, to put something that folk will immediately and instinctively recognise and accept is a fair way to pose the issue."
"We are firmly of the view such a format will give Scottish people the opportunity to express their democratic view on the matter of independence."
Mr Gould said an additional question in the referendum could confuse voters and argues that if increased devolution is to be considered, a second referendum should be held.
He said including a second question in the referendum could "make it very difficult for the voters to have a clear picture...If you want to do a second question, it should be a second referendum if the first one doesn't pass."
Dr Qvortrup said: “Every people has a right to a self-determination but that right can only be exercised if they are asked a clear and unequivocal question.”
Labour's Johann Lamont, Tory Ruth Davidson and Liberal Democrat Willie Rennie, the leaders of the three main opposition parties at Holyrood, have now written to Mr Salmond, asking him to consider the question compiled by the expert group.
Ms Lamont said: “This independent body of work represents a real opportunity for all sides of this debate to reach a consensus on one of the fundamental parts of the referendum.
“The question has to be fair in order that the result properly reflects the will of the Scottish people and by endorsing the question put forward by the expert panel this ensures that no advantage can be gained from either side.
“I hope that we reach agreement with the First Minister on this at the next meeting of the party leaders and move on to the real debate about our country’s future.”
Ms Davidson added: “Surely Alex Salmond will agree his referendum on separation must produce a clear result and that is precisely what the expert panel’s simple, unbiased question was devised to deliver.
“It is obvious from the panel’s excellent work that a referendum is only effective when there is clarity on both the issue and the question, so this must rule out any notion of a further question on devolution which would produce nothing but confusion.
“The people of Scotland face the most important vote in 300 years and I am very grateful to the panel for producing a clear, fair and decisive single question, and I urge the First Minister to accept and adopt the findings.”
Mr Rennie said: “This panel is the only independent expert panel that has been established to draft the question for the referendum.
“We know that Stephen Tierney, adviser to the First Minister, has refused to draft a question for the Scottish Government. So the proposal from this expert group will help us all reach a conclusion to this matter.”
A Scottish Government spokesman said: “There is no reference to the ‘United Kingdom’ in this proposed question, unlike in the poll commissioned by the anti-independence ‘Better Together’ campaign as recently as May, and in stark contrast to the statements of all the opposition parties.
“That is appropriate, because people understand that the Queen will be Head of State of an independent Scotland, and therefore Scotland and England will be united kingdoms.
“And of course this report entirely undermines the premise of the Scottish Affairs Committee’s inquiries into ‘separation’ – being pursued by Labour, Tory, and Lib Dem MPs at Westminster – because the panel agree that the issue is Scotland becoming ‘independent’.”