Production of a Higgs Boson and a Heavy Fermion Pair in Polarized e - e + Collisions (II)

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PRODUCTION OF A HIGGS BOSON AND A HEAVY FERMION PAIR IN POLARIZED e  e  COLLISIONS (II) S. K. Abdullaev and M. Sh. Gojayev

UDC 539.12-17

The production of a Higgs boson H (h; A) and a heavy fermion pair in arbitrarily polarized electron-positron collisions is investigated for the minimal supersymmetric model. The mechanisms of emission of the Higgs boson H (h) by the vector Z 0 boson, of the decay of the Z 0 boson into the H (h) and A bosons, and of the subsequent production of the heavy fermion pair with further decay of the A and H (h) bosons are studied in detail. Analytical expressions for the differential cross sections and left-right and transverse spin asymmetries are obtained, and dependences of the cross sections and the spin asymmetries on the escape angle and the energy of the Higgs boson A ( H ; h) are studied. The results are illustrated with graphs. Keywords: minimal supersymmetric standard model, Higgs boson, electron-positron pair, heavy fermion pair.

INTRODUCTION

The standard model (SM) well describes physics of strong and weak electromagnetic interactions of quarks and

   leptons with gauge bosons [1–3]. A doublet of scalar fields     whose neutral component possesses a nonzero  0    vacuum value is introduced into the model. As a result of spontaneous breaking of the local gauge symmetry due to quantum excitations of the scalar field, the Higgs boson H SM is produced, and as a result of interaction with this field, gauge bosons, quarks, and charged leptons acquire masses. This mechanism of fundamental particle mass production is known as the Higgs mechanism of spontaneous gauge symmetry breaking. However, until recently, the Higgs boson has not been discovered experimentally. Only in 2012, the ATLAS and CMS Collaborations discovered the Higgs boson using the Large Hadron Collider [4, 5] (see also reviews [6–8]). The new stage of research into the nature of the given particle started from this discovery. Along with the SM, the Minimal Supersymmetric Standard Model (МSSМ) [1, 9–12] is widely discussed in the literature. Unlike the SM, two doublets of the scalar field are considered in this model, and after spontaneous symmetry breaking, the Higgs particles H , h, A , H  , and H  arise. In [13], we investigated the process of production of a standard Higgs boson and a light fermion pair in arbitrary polarized electron-positron collisions. The joint production of the Higgs boson H SM and the heavy fermion pair f f was considered in [14, 15]. In [16] we discussed the joint production of Higgs SSМ bosons MSSM H , h, and A and the heavy fermion pair in arbitrary polarized electron  positron collisions e  e  H (h; A)  f  f , where f f can be the lepton (   ) or quark ( bb , tt ) pair. In this work (call it work I), diagrams a and b of emission of the Higgs boson  ( H , h, A) by the heavy fermion and the

antifermion were calculated. Because of limitations on the volume of work I, diagrams c, d, and e were not calculated.

Baku State University, Baku, the Azerbaijan Republ