Recent result from E821 experiment on muon g−2 and unconstrained minimal supersymmetric Standard Model

Abstract

Recently, the E821 experiment at the Brookhaven National Laboratory announced their latest result of their muon g − 2 measurement which is about 2.6-σ away from the standard model prediction. Taking this result seriously, we examine the possibility to explain this discrepancy by the supersymmetric contribution. Our analysis is performed in the framework of the unconstrained supersymmetric standard model which has free seven parameters relevant to muon g − 2. We found that, in the case of large tan β, sparticle masses are allowed to be large in the region where the SUSY contribution to the muon g − 2 is large enough, and hence the conventional SUSY search may fail even at the LHC. On the contrary, to explain the discrepancy in the case of small tan β, we found that (i) sleptons and SU (2) L gauginos should be light, and (ii) negative search for the Higgs boson severely constrains the model in the framework of the mSUGRA and gauge-mediated model. *

Can the Higgs sector contribute significantly to the muon anomalous magnetic moment?

“…The constraint on m A is deduced from the absence of Z → hA (either by direct observation or as inferred from the measured width of the Z), which implies that m A > ∼ 80 GeV. 11 Finally, in a general 2HDM, m H ± > ∼ 78.7 GeV [21]. One noteworthy consequence of m h ∼ 10 GeV is the possibility of mixing between the h and the 0 ++ bb bound states χ b0 (1P ) and χ b0 (2P ), as discussed in refs.…”

“…Moreover, the MSSM provides additional mechanisms for generating significant contributions to δa NP µ . A number of recent papers [7,8,9,10,11] have shown that the recent BNL measurement is compatible with supersymmetric contributions to δa NP µ involving chargino and neutralino exchange, over an interesting region of MSSM parameter space.…”

Muon anomalous magnetic dipole moment in supersymmetric theories

“…The maximum allowed value for ͉͉ is taken to be 1000 GeV. The contours are shown from bottom to top for tan ␤ϭ2, 3,6,10,20,30,40,50. The black bars on the right vertical axes indicate the 1and 2-allowed regions from the Brookhaven E821 experiment.…”

“…Predictions for a SUSY Ϫa SM in dilaton-dominated supergravity models with various tan ␤ϭ2,3,6,10, 20, 30,40 ͑from bottom to top͒, as a function of the lighter chargino mass and the lighter smuon mass. All charged superpartners are required to have mass above 100 GeV.…”

Muon g-2 and implications for supersymmetry

“…out over the recent months [35,36,37,38,39] exploring the effects of the g − 2 constraint become more stringent but a significant part of the parameter space is still allowed [37].…”