The like-sign dimuon charge asymmetry at the Tevatron: corrections from B meson fragmentation

TL;DR

This paper investigates how B meson production mechanisms and fragmentation differences affect the theoretical predictions of the like-sign dimuon charge asymmetry at the Tevatron, highlighting a 10% shift due to these effects.

Contribution

It introduces the impact of B meson fragmentation functions and production fractions on the asymmetry prediction, which were previously neglected.

Findings

Fragmentation effects shift the asymmetry prediction by about 10%.

The asymmetry is sensitive to the B meson production fractions used.

Production mechanism details influence the charge asymmetry measurement.

Abstract

The existing predictions for the like-sign dimuon charge asymmetry at the Tevatron are expressed in terms of parameters related to B mesons' mixing and inclusive production fractions. We show that in the realistic case when phase-space cuts are applied, the asymmetry depends also on the details of the production mechanism for the B mesons. In particular, it is sensitive to the difference in the fragmentation functions of B^0_d and B^0_s mesons. We estimate these fragmentation effects and find that they shift the theory prediction for this observable by approximately 10%. We also point out the approximately 20% sensitivity of the asymmetry depending on which set of values for the B meson production fractions is used: as measured at the Z pole or at the Tevatron. The impact of these effects on the extraction of A^s_{SL} from the D\O measurement is presented.