Photon - axion conversions in static electromagnetic fields of the size a × b × c are considered in detail by the Feynman diagram methods. The differential cross sections are presented and the numerical evaluations of the total cross section are given. Our result shows that the conversion cross-sections in the electric field are quite small, while in the strong magnetic field, the cross-sections are much enhanced, which can be measurable in current experiments. | Communications in Physics, Vol. 23, No. 1 (2013), pp. 21-28 PRODUCTION CROSS SECTIONS OF AXION IN A STATIC ELECTROMAGNETIC FIELD DANG VAN SOA Hanoi National University of Education TRAN DINH THAM Pham Van Dong University, Quang Ngai, Vietnam Abstract. Photon - axion conversions in static electromagnetic fields of the size a × b × c are considered in detail by the Feynman diagram methods. The differential cross sections are presented and the numerical evaluations of the total cross section are given. Our result shows that the conversion cross-sections in the electric field are quite small, while in the strong magnetic field, the cross-sections are much enhanced, which can be measurable in current experiments. I. INTRODUCTION In the 1970’s, Peccei and H. Quinn [1] have shown that the strong CP problem can be solved by the introduction of a light pseudoscalar particle, called the axion [2]. At present, the axion mass is constrained by laboratory searches [3] and by astrophysical and cosmological considerations [4] to between 10−6 eV and 10−3 eV. If the axion has a mass near the low limit of order 10−5 eV, it is a good candidate for the dark matter of the universe. Besides that, an axino (the fermionic partner of the axion) naturally appears in SUSY models [5, 6], which acquire a mass from three - loop Feynman diagrams in a typical range between a few eV up to a maximum of 1 keV [7, 8]. Recently, the candidates for dark matter have been done in extended models of the standard model, such as in the 3-3-1 models [9], or in extra-dimensional gauge fields [10]. A particle, if it has a two - photon vertex, may be created by a photon entering an external electromagnetic (EM) field, the axion is one such particle. So far almost all experiments designed to search for light axions make use of the coupling of the axion to photons. Conversion of the axions into EM power in a resonant cavity was first suggested by Sikivie [11]. He suggested that this method can be used to .
