To find out for certain:
- Consult the offer letter you signed to accept the position, or your most recent annual appointment form
- Ask your chair, chief, or department/section administrator
- Contact the Office of Academic Affairs
In all likelihood:
If you are in a 'basic science' department (Ben May Department for Cancer Research, Biochemistry & Molecular Biology, Ecology & Evolution , Human Genetics, Microbiology, Molecular Genetics & Cell Biology, Neurobiology, Organismal Biology & Anatomy , Pharmacological and Physiological Sciences, Public Health Sciences), you are in the BSD track
If you care for patients, run a clinical laboratory, are a veterinarian, or otherwise assist patient care (e.g., physicist designing therapeutic radiation doses, electrical engineer assisting clinical electrophysiology), you are in the SOM track
If you are a researcher in a 'clinical' department and perform no patient care, you are in the BSD track.
These are generalities, however. Some patient caregivers perform tenurable research and join the BSD track. Some faculty appointed before the current tracks system are 'grandfathered'. Two 'basic science' departments include SOM track faculty.