Someone please guide me to how I can make my plot Gaussian

Roofit and RooStats
1

Screenshot from 2024-05-16 22-43-22
Screenshot from 2024-05-16 22-43-221920×1080 93.3 KB

from this to

Screenshot from 2024-05-21 18-18-55
Screenshot from 2024-05-21 18-18-55931×522 66.6 KB

this

2

May be create your histogram with more bins ?