Production of the B_c meson at the CEPC

Abstract

In this paper, we make a detailed study on the production of the B_c, B_c^*, B_c(2,^1S_0), and B^*_c(2,^3S_1) mesons via the three planned running modes (Z, W, and H) at the future Circular Electron–Positron Collider (CEPC). The fragmentation-function and full nonrelativistic QCD approaches are adopted to calculate the production cross sections. Considering the excited states shall decay to the ground B_c state (e.g. 1^1S_0-state) with almost 100% probability, our numerical results show that up to next-to-leading order QCD corrections, there are about 1.4times 10^8B_c events to be accumulated via the Z mode (sqrt{s}=m_{_Z}) of the CEPC, but only about 1.6times 10^4 and 1.1times 10^4B_c events to be accumulated via the W (sqrt{s}=160,mathrm{GeV}) and H (sqrt{s}=240,mathrm{GeV}) modes, respectively. Since the Z mode is the best mode among the three planned modes of the CEPC for studying the production of the B_c, B_c^*, B_c(2,^1S_0), and B^*_c(2,^3S_1) mesons and the differential distributions of these mesons may be measured precisely at this mode, we further present the differential cross sections dsigma /(dz,dmathrm{cos}theta ) and dsigma /dz via the Z mode of the CEPC.