We have new insight into the question of the author of Hebrews from an unlikely source; the field of engineering. Derek Abbott, a friend of mine, together with others, have published this article with a new method for analysing authorship of documents. They apply their method to the authorship of Hebrews. Of the authors analysed, Paul comes out as the most likely author, followed by Luke.
I would point out that the strongest argument against Pauline authorship of Hebrews is Hebrews 2:3. ‘This salvation, which was first announced by the Lord, was confirmed to us by those who heard him’
The argument is that since Paul heard Jesus personally (on the Damascus Rd), he would not have written this verse. It is quite a persuasive argument, however there are ways to read this which don’t rule out Pauline authorship.
For example, one of the early claims for authorship is that Paul wrote Hebrews in Hebrew, and that Luke translated it. Perhaps Luke changed 2:3 to read as it now does. In my estimation, there is a reasonable probability that Paul had his hand in the writing of the epistle.
On a related subject, I wonder if Derek and his mates would apply their method to the authorship of the disputed Pauline letters? I’m quite confident they will come out looking strongly Pauline, since I’m very confident that himself wrote them….. But I dare say that would be unlikely to persuade the sceptics.