^^^
Technically speaking, yes you can since Haswell and Broadwell are both socket 1150 CPUs. However, similar to upgrading Sandy Bridge to Ivy Bridge, the mobo manufacturer will need to release a BIOS upgrade. The BIOS basically has a list of compatible CPUs. If a particular CPU is not "on that list", then your PC may not boot up, or if it does then it might only run at minimal speed.