I had this persist for several months, during the first 10,000 miles. Belt tightened at the dealer, noise went away for about a month. Used chapstick on the outside of the belt, noise went away for about a month and came back.
Dealer finally got enough complaints that they did some research and found that Polaris was aware of a "bad batch" of rear sprockets (pulleys) and got it replaced under warranty. They did 4 replacements in a week...
If you've had all of the routine maintenance already suggested above, might be worth pursuing.
2013 XCT Sunset Red, Tri-oval Stage 1 Exhaust, Lloydz ATS (+4), Lloyds High-flow Air Filter, Lloydz VFC III, Kicker Speakers, Electric Reverse Kit, Ultimate Seat w/Backrest, Passenger Armrest, Madstad Road Glide, Ness Beveled Gas Cap/Derby/Cam, FOBO TPMS,Centramatics Martinez, GA