Muon anomalous magnetic moment from effective supersymmetry

S. Baek; P. Ko; Jae-hyeon Park

doi:doi:10.1007/s10052-002-0971-5

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2022 Impact factor 4.4

Particles and Fields

Eur. Phys. J. C 24, 613-618 (2002)
DOI: 10.1007/s10052-002-0971-5

Muon anomalous magnetic moment from effective supersymmetry

S. Baek¹, P. Ko² and Jae-hyeon Park²

¹ School of Physics, KIAS, Seoul 130-012, Korea
² Department of Physics, KAIST, Daejeon 305-701, Korea

(Received: 29 March 2002 / Published online: 14 June 2002 )

Abstract
We present a detailed analysis on the possible maximal value of the muon $(g-2)_\mu \equiv 2 a_\mu$ within the context of effective SUSY models with R parity conservation. First of all, mixing among the second and the third family sleptons can contribute at one loop level to $a_\mu^{\mathrm {SUSY}}$ and $\tau \rightarrow \mu \gamma$ simultaneously. One finds that $a_\mu^{\mathrm {SUSY}}$ can be as large as (10- $20)\times 10^{-10}$ for any $\tan\beta$ , imposing an upper limit on the $\tau \rightarrow \mu \gamma$ branching ratio. Furthermore, the two loop Barr-Zee type contributions to $a_\mu^{\mathrm {SUSY}}$ may be significant for large $\tan\beta$ , if a stop is light and $\mu$ and A_t are large enough ( $\sim O(1)$ TeV). In this case, it is possible to have $a_\mu^{\mathrm {SUSY}}$ up to $O(10) \times 10^{-10}$ without conflicting with $\tau \rightarrow l \gamma$ . We conclude that the possible maximal value for $a_\mu^{\mathrm {SUSY}}$ is about $\sim 20 \times 10^{-10}$ for any $\tan\beta$ . Therefore the BNL experiment on the muon $a_\mu$ can exclude the effective SUSY models only if the measured deviation is larger than $\sim 30 \times 10^{-10}$ .