Abstract
The ATLAS collaboration recently reported a $3\sigma$ excess in the leptonic-$Z+jets+E_{T}^{miss}$ channel. We intend to interpret this excess by squark pair production in the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The decay chain we employ is $\tilde{q} \to q \tilde{\chi}_2^0 \to q \tilde{\chi}_1^0 Z$, where $\tilde{\chi}_1^0$ and $\tilde{\chi}_2^0$ denote the lightest and the next-to-lightest neutralinos with singlino and bino as their dominant components respectively. Our simulations indicate that after considering the constraints from the ATLAS searches for $jets + E_{T}^{miss}$ signal the central value of the excess can be obtained for $m_{\tilde{q}} \lesssim 1.2 {\rm TeV}$, and if the constraint from the CMS on-$Z$ search is further considered, more than 10 signal events are still attainable for $m_{\tilde{q}} \lesssim 750 {\rm GeV}$. Compared with the interpretation by gluino pair production, the squark explanation allows for a significantly wider range of $m_{\tilde{q}}$ as well as a less compressed SUSY mass spectrum. We also show that the squark explanation will be readily tested at the initial stage of the 14 TeV LHC.
Highlights
JHEP10(2015)178 to obtain if only the neutralino serves as the dark matter candidate
We intend to interpret this excess by squark pair production in the Next-to-Minimal Supersymmetric Standard Model (NMSSM)
In the Next-to Minimal Supersymmetric Standard Model (NMSSM) [15], a singlino-dominated neutralino has the property, and if it acts as the LSP, the correct relic density can be achieved by multiple annihilation channels [15, 16]
Summary
As one of the most economical extensions of the MSSM, the NMSSM contains one gauge singlet Higgs superfield Sin its matter content. The χ0i χ0j h coupling with h denoting the SM-like Higgs boson depends on all components of the neutralinos, and there may exist cancelations among different contributions These characters are helpful to understand our explanation of the Z-excess. We ad hoc require that only χ01 and χ02 among the neutralinos are lighter than the squarks This will simplify our analysis, but on the other hand, since the rate and various kinematic distributions of the process pp → qq → χ01Zqχ01Zq are decided by few parameters, the capability of our scenario to interpret the excess is limited given that the scenario must satisfy the constraints mentioned above.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
