You need to read the lease carefully. Usually, there is a "warrant of habitability" which requires the Landlord to provide a living space that is "habitable". If the neighbors prevent you from sleeping, the space is not "habitable". You would seek redress in court for a partial rebate on your rent.

First, document the issue in several certified letters to the Landlord, mailed every week and stating the problem each time. This builds your case. If the Landlord refused to do anything about it, you've got some good evidence to bring before a judge.

If you're in a tenant friendly state, it's possible to get 50% of your rent returned to you if you convince the judge of how miserable the accommodations were.

I've had it happen to me........by a very destructive and creative tenant.