2009/11/09 by Yu-Jie Zhang, Hua-Sheng Shao, Zhang, Yu-Jie +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #hep-ex #hep-ph
paper · pdf · doi:10.48550/arxiv.0911.1766
Comments are wellcome
arxiv created 2010/04/13 · arxiv updated 2010/04/14
We calculate the inclusive decay width of Υ→ l+ l-. Then we get the ratio Rτμ=Γ[Υ→ τ+τ-]/ Γ[Υ→ μ+μ-] to \calO(α) and \calO(αs2) within the Standard Model(SM). Comparing with the recent Babar's data Rτμ=1.005±0.013± 0.022, we find that SM prediction Rτμ is not consistent with the experimental data in the error bar. The discrepancy is about 1.25σ. So leptonic decay of Υ may be a possible signature of New Physics(NP). We present a better approach to test the Standard Model, Rτμ(Esoft)=.Γ[Υ→ τ+τ-+X]/ Γ[Υ→ μ+μ-+X]|_EX<Esoft. After resumming the large logarithms, we get Rτμ(Esoft) at the precision level of 0.1%. It can be compared with experimental data more precise. We also consider the impact of Rτμ(Esoft) and Rτμ from light Higgs h and pseudoscalar Higgs A0.