O 1 $$ \mathcal{O}(1) $$ GeV dark matter in SUSY and a very light pseudoscalar at the LHC
Chengcheng Han (Asia Pacific Center for Theoretical Physics, San 31, Hyoja-dong, Nam-gu, Pohang, 790-784, South Korea); Doyoun Kim (Asia Pacific Center for Theoretical Physics, San 31, Hyoja-dong, Nam-gu, Pohang, 790-784, South Korea); Shoaib Munir (Asia Pacific Center for Theoretical Physics, San 31, Hyoja-dong, Nam-gu, Pohang, 790-784, South Korea); Myeonghun Park (Asia Pacific Center for Theoretical Physics, San 31, Hyoja-dong, Nam-gu, Pohang, 790-784, South Korea, Kavli IPMU (WPI), The University of Tokyo, Kashiwa, Chiba, 277-8583, Japan, Department of Physics, Postech, Pohang, 790-784, South Korea)
We analyze the prospects of the detection of an O 1 $$ \mathcal{O}(1) $$ GeV neutralino dark matter, χ ˜ 1 0 $$ {\tilde{\chi}}_1^0 $$ , in the Next-to-Minimal Supersymmetric Standard Model at the 14 TeV LHC. We perform dedicated scans of the relevant parameter space of the model and find a large number of points where the thermal relic abundance due to such a dark matter is consistent with the PLANCK measurement. We note that this dark matter is highly singlino-dominated and is always accompanied by a pseudoscalar, A 1 , with a mass around twice its own, which is responsible for its resonant annihilation. For two benchmark points from our scan, we then carry out a detector-level signal-to-background analysis of the pair production of a heavier higgsino neutralino and a chargino. The higgsino thus produced decays into the dark matter and either the Z boson or the A 1 . For the Z -associated production of χ ˜ 1 0 $$ {\tilde{\chi}}_1^0 $$ , we investigate the scope of the trilepton search channel. For the A 1 -associated production mode, in order to identify the two collimated muons coming from the decay of the A 1 , we employ an unconventional method, of clustering them together into one jet-like object. Using this method, for certain parameter space configurations, a much larger sensitivity can be obtained at the 14 TeV LHC for the A 1 χ ˜ 1 0 $$ {A}_1\;{\tilde{\chi}}_1^0 $$ channel compared to the Z χ ˜ 1 0 $$ Z{\tilde{\chi}}_1^0 $$ channel, with an integrated luminosity of 300 fb −1 .
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