Can non-US citizens play? What if a non-US citizen wins?
Yes, non-US citizens can legally play, and non-US citizens are eligible to win any prize offered in the game.
If a non-US citizen wins, they would claim
their prize in the same manner that a US citizen would, but the taxes
withheld would be different. For example, federal withholding for
non-US citizens is a flat 30%. Also, individual states may have
different tax structures for non-US citizens than they do for US
citizens. Depending on which country the person is a legal resident
of, there also may be tax treaties between the US and that other
country which could be helpful in offsetting whatever the US tax
liabilities are.
In short, non-US citizens can play and win
Powerball. If a non-US citizen wins a large prize, they will be
responsible for some amount of tax, which in the end will probably be
an amount similar to what a US citizen would pay, but there are so many
possible variations with international tax codes that you'll need to
consult with a local tax attorney if you need to know a precise amount
of tax liability.
http://www.usamega.com/powerball-faq.htm