Initial access to the base station when the mobile phone is first powered on

When the mobile phone (equipment) is first powered on, it first goes to scan the list of frequencies in its SIM card provided by the telecom operator.

During this process, the mobile scans the multiple frequencies by measuring power of these frequencies and lists them based on their strengths.

At that point in time (during the scanning process).

I am first trying to understand the followings:

  1. What is the name of the frequency set that the mobile user is scanning?
  2. Are they all Primary and Secondary Synchronization signals so that after measuring their power, the mobile user will list them based on the power and then starts decoding them to find which base station is transmitting these scanned frequencies towards the mobile phone?

Thanks in advance.