MySQL 5.5 hangs frequently in production environment (no replies)

Hello All,

We have our Mysql production database (ver 5.5.2) running on on HP-UX (ver 11.31) and use InnoDB engine.
Lot of operations are occuring on this database. We are encountering complete database hang issue frequently.No error is reported in the error log during the issue.

Database buffer pool (innodb_buffer_pool_size) has been set to 10GB and we have sufficient memory available at OS level (64GB).

Please assist in resolving this hang issue.

Thanks.