can I have 0 hours recorded for some process groups in my PMP application? as I was not involved in all the process groups.
This is what mentioned in PMI handbook. Here is the link for PMI site. http://www.pmi.org/Certification/Project-Management-Professional-PMP.aspx
PMP Eligibility Requirements
To be eligible for the PMP credential, you must meet certain educational and professional experience requirements. All project management experience must have been accrued within the last eight consecutive years prior to your application submission.
Secondary degree (high school diploma, associate’s degree or global equivalent) OR
Four-year degree (bachelor’s degree or global equivalent)
Project Management Experience
Minimum five years/60 months unique non- overlapping professional project management experience during which at least 7,500 hours were spent leading and directing the project*
Minimum three years/36 months unique non-overlapping professional project management experience during which at least 4,500 hours were spent leading and directing the project*
Project Management Education
- 35 contact hours of formal education
*Leading and directing the project as identified with the tasks, knowledge, and skills specific in the Project Management Professional Examination Content Outline.
You should have experience in all five process groups across all your project management experience submitted on the application. However, on a single project, you do not need to have experience in all five process groups.
Source: pmi.org PMP Handbook
Since PMP candidates should demonstrate experience in "Leading and directing the project", it is indeed required to have experience in all five process groups. But, as quoted correctly by Sreedhar, you do not have to demonstrate experience in all Five process groups for each individual project you add to your experience list. Only the total matters.