Answer:
Option (D)
Step-by-step explanation:
A particle accelerator is usually defined as a machine that is constructed in such a way that it uses the electromagnetic fields in order to move the charged particles up to an extremely high speed as well as energy, containing them in a properly structured beam.
When the photon particles of a helium atom are introduced in a particle accelerator, then the small particles commonly known as Helium quarks are being studied by the scientists.
These quarks are smaller particles that fuse protons and neutron by a strong force. These are comparatively heavier than the electrons and have an average size of about 10^−18 m.
Thus, the Helium quarks are studied.
Therefore, the correct answer is option (D).