Yes, Bhavanga is a state of mind, but there are also cittas inside a Citta Vitthi, that are, at least in CMA called e.g.
V= “Vibrational bhavanga”
A=”arrest bhavanga”
See page 166 on the Mind door process.
Since page 127 refers to the “investigation citta” as appearing in bhavanga citta, rebirth and death, I assume what is meant must be the above V and A cittas, right?
Page 122:
“Adverting (±vajjana): When an object impinges at one of the
sense doors or at the mind door, there occurs a mind-moment called
bhavanga-calana, vibration of the life-continuum, by which the bhavanga
consciousness “vibrates” for a single moment. This is followed by another
moment called bhavanga-upaccheda, arrest of the life-continuum, by
which the flow of the bhavanga is cut off. Immediately after this, a citta
arises turning to the object, either at one of the five physical sense doors
or at the mind door. This function of turning to the object is termed
adverting.”
Page 139:”A mental object apprehended in the mind door in the last javana
process of the previous existence may become an object of the rebirth-
linking, bhavanga, and death consciousnesses of the new existence as a
kamma or as a sign of kamma that is past. If the object should be a sign
of destiny, it is usually a visible form apprehended in the mind door and
is present.”
Bhikkhu Bodhis book talks about Process-freed cittas, which is something that you dispute, right? For you, there is no bhavanga citta but only a state of Bhavanga..?