BURLINGTON, Vt. — Ice cream maker Ben & Jerry has a new CEO who has challenged the company to “double its social impact.” Matthew McCarthy became CEO on July 1. The marketing executive is a veteran of Ben & Jerry’s parent company, Anglo-Dutch consumer goods multinational Unilever, where he has worked for 21 years. The maker of Chunky Monkey and Cherry Garcia said McCarthy led some other Unilever brands to adopt food production standards similar to Ben & Jerry’s, such as Hellman’s using certified cage-free eggs in its mayonnaise.