Antiproton

The antiproton was a particle, an antimatter element with the opposite charge of a proton. In the early 25th century, antiproton energy constituted a common directed energy weapons type by the Alpha Quadrant Alliance. 

Technical use
In the 2365, the spin reversal system of the Federation starship USS Yamato (NCC-71807) generated antiprotons. This was marked on a schematic on the secondary hull. 

In 2368, the USS Enterprise (NCC-1701-D) was able to track the brancher known as the Crystalline Entity by its trail of antiprotons. 

In 2369, Starfleet identified that the trace of residual antiprotons from firing a Romulan disruptor could be used to date when such a weapon had been fired. 

In 2371, the Jem'Hadar were able to detect the cloaked USS Defiant (prototype) by using antiproton beams. 

When Tom Paris suffered mutation from a transwarp test flight in 2372, the Doctor of USS Voyager used bursts of antiprotons to reverse the mutation on a DNA-level. 

In 2373, the deflector dish of Federation ships was charged with antiprotons. 

Residual antiprotons emanating from cloaked ships could be used to detect such vessels. In 2379, the prototype employed an advanced form of cloaking device that left no detectable antiproton trace. 

Antiproton weaponry
In 2267, the planet killer employed an antiproton beam, consisting of pure antiprotons only, to destroy planets. 

In 2366, the illusory Delta Rana warship, created by the Douwd Kevin Uxbridge to mimic the Husnock warship that ravaged Delta Rana IV, used beams of antiprotons and positrons. Its firepower could be modulated from the equivalent to forty megawatts to 400 gigawatts. 

By 2409, antiproton-based directed energy weapons were available for handheld and shipboard use. 

Borg Unimatrix 0047 command ships fired antiproton weapons. 

The bio-neural warheads equipped on Klingon battlecruisers dealt antiproton damage. 

The Solanae-made Obelisk 1 starship fired antiproton weapons. 

When the science dreadnought was launched during the Iconian War of 2410, vessels of the class were pre-equipped with a chroniton lance that fired antiproton beams. 

Other factions using antiproton-based directed energy weapons as a default during the 2400s and 2410s decades included: the Crystalline Entity, Fek'Ihri Horde, Iconian Empire, Malon Cooperative, Sphere Builders, Undine, and Voth. 

In the 29th and 31st centuries, ships of the resurgent Terran Empire, like the temporal dreadnought, fired antiproton weapons.