tailieunhanh - Properties of axion production in yu- collision

Properties of axion production in yu− collision are considered in detail using the the Feynman diagram method. The differential cross-sections are presented and numerical evaluations are given. Based on results obtained it was found that the cross sections depend strongly on the polarization factors of u− beams and are much larger than in axion production in ye- collision. In addition, some estimates for experimental conditions are derived from our results. | JOURNAL OF SCIENCE OF HNUE Mathematical and Physical Sci. 2013 Vol. 58 No. 7 pp. 132-137 This paper is available online at http PROPERTIES OF AXION PRODUCTION IN γµ COLLISION Dao Thi Le Thuy1 and Le Nhu Thuc2 1 Faculty of Physics Hanoi National University of Education 2 Department of Post Graduate Hanoi National University of Education Abstract. Properties of axion production in γµ collision are considered in detail using the the Feynman diagram method. The differential cross-sections are presented and numerical evaluations are given. Based on results obtained it was found that the cross sections depend strongly on the polarization factors of µ beams and are much larger than in axion production in γe collision. In addition some estimates for experimental conditions are derived from our results. Keywords Standard Model axion γµ strong-CP. 1. Introduction The Standard Model SM expectations always resulted in very good agreement with the huge number of experimental observations made in the past 40 years and more. The recent discovery of a Higgs boson at the LHC Large Hadron Collider seemingly completes the discovery program for all matter states predicted by the SM. Nevertheless some aspects of the theory remain unexplained and it is possible to make the assumption that SM is not a definitive theory but an approximation at low energy that is the energy currently accessible for particle physics experiments of a more fundamental theory. The strong CP problem is big mystery that is unexplained in the SM. Among various candidate solutions proposed so far the Peccei-Quinn mechanism is the most attractive candidate for the solution of the strong CP problem where the CP-violating phase θ θ 6 10 9 is explained by the existence of a new pseudo-scalar field called the axion 8 . At present the axion mass is constrained by laboratory 5 and by astrophysical and cosmological considerations 12 13 to between 10 6 eV and 10 3 eV. If the axion has a mass near the low