It's hard to see, but might be a type of bidens.

Coreopsis 'Moonbeam'?

It reminds me of a bidens I had a few years back -- but a sharp close-up would help the gurus give a definite answer.

I second the Coreopsis sp. ID. I've photographed it many times in botanical gardens. More common with orange flowers, but does come in red and yellow, too.

I'm going with Coreopsis verticillata.