ATLAS Z-peaked excess in the MSSM with a light sbottom or stop

作者：Kobakhidze, Archil; Liu, Ning^*; Wu, Lei; Yang, Jin Min

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2015, 92(7): 075008.

DOI：10.1103/PhysRevD.92.075008

• MISSING TRANSVERSE-MOMENTUM
• PP COLLISIONS
• SEARCH
• EVENTS
• SQUARK
• BOSON
• JETS

We attempt to explain the recent ATLAS 3 sigma excess of dilepton events with an invariant mass near Z peak through the gluino-mediated sbottom production in a simplified scenario inspired by the minimal supersymmetric Standard Model. The additional Z bosons can be produced through the cascade decay chain (g) over tilde -> b (b) over tilde1(dagger) -> b (b) over bar(chi) over tilde (0)(2,3) -> b (b) over bar(chi) over tilde (0)(1)Z, in which (b) over tilde (1) is the right-handed sbottom, (chi) over tilde (0)(1) is the bino-like lightest supersymmetric particle (LSP) and (chi) over tilde (0)(2,3) are two nearly degenerate Higgsino-like next-to LSPs. Taking into account the constraint from the LHC search for the gluino-mediated sbottom production in the final states with the missing transverse energy and at least three b-jets, we find that the ATLAS on-Z excess can only be marginally explained at the 2 sigma level. We also note that within the scenario where the gluino predominantly decays to the right-handed stop instead of the sbottom, the excess can hardly be explained, since the Z-boson is not produced in the stop dominant decay channel, (t) over tilde (1) -> b (chi) over tilde (+)(1).

• 出版日期2015-10-7
• 单位河南师范大学