Probing axino LSP from diphoton events with large missing transverse energy

作者：Chang Sanghyeon; Lee Kang Young; Song Jeonghyeon^*

来源：Physics Letters B, 2012, 717(1-3): 193-196.

DOI：10.1016/j.physletb.2012.09.009

In a supersymmetry model with an axino as the lightest supersymmetric particle (LSP) and a Bino as the next LSP (NLSP), supersymmetric particle production ends up with including two Binos, followed by each Bino%26apos;s decaying into a photon and an axino. Final states are diphoton with large missing energy. In a benchmark scenario, we have comprehensively studied the implication of gamma gamma + is not an element of((T)) data from the ALEPH, CDF II, ATLAS and CMS experiments. No excess over the standard model backgrounds can be explained in this model if the Bino NLSP decays outside the detector. Long life time of the Bino is possible because of high Peccei-Quinn symmetry breaking scale f(a). The ALEPH and CDF II data put a very strong bound on f(a) for light Bino case with m((B) over tilde) less than or similar to 150 GeV: the narrow hadronic axion window around f(a) similar to 10(6) GeV is completely closed. The recent ATLAS and CMS data show very interesting bound on f(a) greater than or similar to 10(5) GeV for the Bino mass below 700 GeV. This is already stronger than the previous laboratory bounds.

• 出版日期2012-10-22