Question

what are tachyons?give a detail of them

Answer 1

A tachyon or tachyonic particle is a hypothetical particle that always moves faster than light. The word comes from the greek pronounced tachy which means meaning rapid.

Answer 2

A tachyon /ˈtæki.ɒn/ or tachyonic particle is a hypotheticalparticle that always moves faster than light. Most physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics.[1][2]If such particles did exist, they could be used to build atachyonic antitelephone and send signals faster than light, which (according to special relativity) would lead to violations of causality.[2]The possibility of particles moving faster than light was first proposed by O. M. P. Bilaniuk, V. K. Deshpande, and E. C. G. Sudarshan in 1962, although the term they used for it was "meta-particle".[3] In the 1967 paper that coined the term,[4]Gerald Feinberg proposed that tachyonic particles could be quanta of a quantum field with imaginary mass. However, it was soon realized that excitations of such imaginary mass fields do not in fact propagate faster than light,[5] and instead represent an instability known as tachyon condensation.[1] Nevertheless, in modern physics the term "tachyon" often[1][6] refers to imaginary mass fields rather than to faster-than-light particles. Such fields have come to play a significant role in modern physics.The term comes from the Greek: ταχύ, tachy, meaning "rapid". The complementary particle types are called luxons(which always move at the speed of light) and bradyons(which always move slower than light); both of these particle types are known to exist.Despite theoretical arguments against the existence of faster-than-light particles, experiments have been conducted to search for them. No compelling evidence for their existence has been found. In September 2011, it was reported that a tau neutrino had travelled faster than the speed of light in a major release by CERN; however, later updates from CERN on the OPERA project indicate that the faster-than-light readings were resultant from "a faulty element of the experiment's fibre optic timing system".