Here is the full list of all 18 Boson X achievements.
Discover the Anti X Boson particle
Discover the Anti Y Boson particle
Discover the Anti Graviton particle
Discover the Anti Radion particle
Discover the Dark X Boson particle
Discover the Dark Y Boson particle
Discover the Anti Acceleron particle
Discover the Anti Geon particle
Discover the Dark Graviton particle
Discover the Dark Radion particle
Discover the Dark Acceleron particle
Discover the Dark Geon particle
Discover the X Boson particle
Discover the Y Boson particle
Discover the Radio particle
Discover the Graviton particle
Discover the Acceleron particle
Discover the Geon particle