Probing New Physics via the $B^0_s\to \mu^+\mu^-$ Effective Lifetime

By K. Bruyn, R. Fleischer, R. Knegjens, P. Koppenburg, M. Merk, A. Pellegrino, N. Tuning. 2012

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We have recently seen new upper bounds for B(s)(0)→μ(+)μ(-), a key decay to search for physics beyond the standard model. Furthermore a nonvanishing decay width difference ΔΓ(s) of the B(s) system has been measured. We show that ΔΓ(s) affects the extraction of the B(s)(0)→μ(+)μ(-) branching ratio and the resulting constraints on the new physics parameter space and give formulas for including this effect. Moreover, we point out that ΔΓ(s) provides a new observable, the effective B(s)(0)→μ(+)μ(-) lifetime τ(μ(+)μ(-)), which offers a theoretically clean probe for new physics searches that is complementary to the branching ratio. Should the B(s)(0)→μ(+)μ(-) branching ratio agree with the standard model, the measurement of τ(μ(+)μ(-)), which appears feasible at upgrades of the Large Hadron Collider experiments, may still reveal large new physics effects.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b9e6b45c5f4e12c1d0af87d75479e12dcabfe7ef