Study on viability of Gain Stabilization of SiPMs and determination of b-quark fragmentation fraction ratio f_c/f_u in pp collisions at √s = 13 TeV with the ATLAS detector

Abstract

Gain Stabilization of SiPMs through the usage of an external board to regulate bias voltage based on temperature yields a variation in gain of less than 0.5 % using a system of four SiPMs with temperature readout in close vicinity. A proper system test should still be explored, although these preliminary tests show promising results. The estimation of B ^+_c mass and the fragmentation ratio f_c/f_u using 2015 and 2016 ATLAS data at √s = 13 TeV yields M_B^+_c = 6268.32 ± 4.77(stat) ± 3.78(syst) MeV c^−2 and f_c/f_u = 3.06 ± 0.51_stat ± 2.72_syst × 10^−4 . The fragmentation ratio of f_c/f_u is determined through the relative efficiency-corrected yields of B^+_c → J/ψπ^+ over B^+_u → J/ψK^+ and the branching fraction ratio B (B^± → J/ψK^±) /B (B^±_c → J/ψπ^±).