Is it surprising there are signs of the heavy quarks? The diagrams that include them have tiny but nonzero values. Hearken back to Hitchhiker's - it is not impossible, just highly improbable.
What’s interesting is that there’s a net charm content: there are more charm quarks to be found than anti-charms.
Given that charm quarks are heavier than the proton, you’d expect to only find them in deep inelastic collisions when they are produced in pairs with an anti-quark, so it is surprising that there’s an asymmetry.
From the article's description it sounds like they tortured the data until it told them what they wanted. If the charm did show up, how long did it exist? In conventional spectroscopy, the broader the line, the shorter the lifetime (and v.v.) It smells like a sub-attosecond lifetime, if that.
It was a bit of an open question what would happen with the heavy charm quarks, given that they each mass more than the entire proton, but yeah... anything else would have been a major surprise.
