An impressively large crowd braved the wintry elements on Tuesday night and made the trip to Iota to catch the local debut of The Ghost of a Saber Tooth Tiger. Of course, ticket sales likely were not hindered by the fact that one principal member of the band is the “Beautiful Boy” of John Lennon and Yoko Ono, while the other is a successful and strikingly beautiful fashion model. Seemingly unfazed by the burden of hype and fame that precedes them, Sean Lennon and Charlotte Kemp Muhl met — or perhaps even exceeded — expectations with an enjoyable performance that marked their musical partnership as one whose fledgling development seems well worth watching.