I have this doubt can dominant is represented by logic 0, can recessive is represented by logic 1 how is this?
Whether a HIGH or LO is represents a logic 1 or 0 is purely up to how the designer (and how the other designers of other equipment interfacing with that component) want to interpret it.
It is like a traffic light. Red = stop and green = go. But if we wanted to, red = go and green = stop. It's just that the designer and people who will be working with the part have to agree with each other. What it actually is doesn't matter.
For recessive it is 0 volts and there are two lines of high and low, but we are speaking of a single logic level. I am not able to understand.
In both differential and non-differential signals, you are measuring the voltage difference between two lines.
But In non-differential lines, one line always sits at at the same reference voltage and does not change (usually GND or 0V) while the voltage on the other line changes.
But in a differential line like the CAN bus, both lines changes in opposite directions. You do not have one line that remains at a fixed static reference voltage. The voltage between the two lines gets closer for one logic level (moves towards a mid-point voltage) and moves farther apart for the opposite logic level.
The HI and LO name for the line is just a name for the lines since one line can have a higher voltage during certain logic states. It's not referring to actual logic levels. You could just name the lines A and B instead of HI and LO.
It's also possible in some protocols for the two differential lines to completely swap voltages with each other for different logic levels, rather than just moving together or away from each other. In this case it doesn't make much sense to names the lines HI and LO.