How to capture USB data on the oscilloscope?
To measure a digital signal the Nyquist-Shannon theorem says you need a scope with a sampling rate at the very least twice as fast as the frequency of the signal you are sampling. An USB 2.0 bus is capable of 480Mbit/s, which means you would need a scope capable of AT LEAST 1GS/s (a billion samples per second) to be able to resolve individual bits. You have the wrong equipment for the job.