In the Anapanasati Sutta, what is the difference between mind and mental processes?
From the Anapanasati Sutta

&quot;Mindfulness of in-&amp;-out breathing, when developed &amp; pursued, is of great fruit, of great benefit. Mindfulness of in-&amp;-out breathing, when developed &amp; pursued, brings the four frames of reference to their culmination. The four frames of reference, when developed &amp; pursued, bring the seven factors for awakening to their culmination. The seven factors for awakening, when developed &amp; pursued, bring clear knowing &amp; release to their culmination.&quot;

The four tetrads correspond to The Four Frames of Reference referred to above. They are (in Pali and English):

Kāyānupassanā satipaṭṭhāna: being mindful of the body as a frame of reference.
Vedanānupassanā satipaṭṭhāna: being mindful of feelings as a frame of reference.
Cittānupassanā satipaṭṭhāna: being mindful of the mind as a frame of reference.
Dhammānupassanā satipaṭṭhāna: being mindful of mental qualities as a frame of reference.

So the second tetrad in your example is mindfulness of feelings (vedanā) and the third is mindfulness of mind (citta).
A basic distinction of these is here:

1: The Body merely as a transient and compounded Form..
2: Feelings just as vanishing Reactions to sense-contact..
3: Mind only as a group of habitual and conditioned Moods..
4: All Phenomena (dhamma) simply as discrete momentary Mental States..