Conversion Cross Sections Between Photon And Weakly Coupled Particles In External Electromagnetic Fields

Detecting the particle of feeble coupling (graviton and axion) in external electromagnetic field, Physicists use the coupling between magnetic field and feeble coupling particle to produce the perturbative photon flux (PPF). According to the different character between the perturbative photon flux and background photon flux, we can separate the perturbative photon flux in experiment, so that know if the feeble coupling particle is exist. However, experimental physicist must face the very feeble act section, and using the lately technology is very different to detect. Therefore, Physicist and experimental physicist will contrive more precision experiment method continually in order to success to detect the feeble coupling particle. This paper introduces the detecting measure of feeble coupling particle simply, and study the feeble coupling particle-photon conversion cross section in external electromagnetic fields.The classical form of graviton, namely the anticipative gravitational waves of principle of general relativity, is a pop question for discussion, whose detecting not only can open a new window for humankind to know nature and explore astrospace, but also make the unification of four fundamental interaction such as strong interaction, weak interaction, electromagnetic interaction and graviton interaction, and it has great force function for solving the question of quantize the gravitational fields. Due to refer the very weak signal, laser-physics, strong magnetic field, vacuum technology and so on, and also refer microwave technology, superconductor and low temperature technology and so on, so success to detect the gravitational wave will advance the development of foundation research and application research, including the prolongation and application in space technology, electron, national defense and military affairs. Axion is the best candidate of dark matter, therefore, success to detect axion will prove many characters of dark matter. The paper sketch the Feynman drawing of produce of axion, and introduce the detect theory by laser, calculate the interaction conversion ratio between axion and photon in succession, from the perturbative photon flux we can obtain the information about axion.Finally, we calculate the unpolarized differential cross section of conversing photon into axion or into graviton by Feynman perturbation techniques in magnetic dipole field, electric dipole field and uniform electrostatic and magnetostatic fields, respectively. It is found that in electric dipole field, the differential cross section vanishes in the same and opposite propagating directions of the photon flux. In the magnetic dipole field such differential cross section generally has non-vanishing values in above mentioned directions, but when the propagating direction of photon flux is parallel to the magnetic dipole vector, the differential cross section is equal to zero. In the uniform electrostatic and magnetostatic fields, non-vanishing differential cross sections occur only in the same and opposite propagating directions of the photon flux, but the latter is weaker than the former. When the mass of axion approaches to zero, the above process expresses some similar characters to the conversion of the photons to the gravitons.