What are the processes involved in planning and research for developing a new product?
Oh man, too broad and expansive a question to answer here, but I'd be happy to chat with you more about what I think about when I work on Startup Digest as a product. https://calendly.com/mitchellcuevas/
Maybe something interesting, my personal definition of marketing is loosely informed on one you can find in a book called 'Spent' (amazing read - http://www.amazon.com/Spent-Sex-Evolution-Consumer-Behavior/dp/0143117238).
It's not a marketing book technically, but invaluable for marketers, especially marketers like myself who tend to include a lot more of the 'product development' aspect of things in their definition of what makes good marketing. It's a very holistic look that some people like from their marketing team and others don't. The point is, marketers own so much of the data that goes along with customers and usually best understand them, that I think they have to be a part of the product creation process as much as they are of the distribution and promotion process.
Personal opinion and not all marketers will agree with it, but hey, I don't care :).