You know that there is a C++ version of Lucene?
http://clucene.sourceforge.net/
There's also Xapian, which is built in C++:
So, if Java's footprint is a concern, there are alternatives.
Apache Lucy is another option that might appeal if you consider Lucene bloated. It's written in C, and while there aren't Go bindings yet, there's great interest in providing them and a couple people starting on them: http://mail-archives.apache.org/mod_mbox/lucy-user/201308.mb...
What about idzebra? It's written in C, it predates Lucene and it was used as the indexing system for Harvest (the origin of Squid).
What is more likely than "low memory footprint" to give an indexing system written in Go an advantage over alternatives is the marketing of Go. It seems the language is being promoted nearly every day on HN's front page. If this is any indication of usage trends among developers, the Go Authors must be pleased.