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Measurement of the Reaction $e^+ e^- \to \mu^+ \mu^-$ for 14-{GeV} $\le \sqrt{s} \le$ 36.4-{GeV}

The CELLO collaboration Behrend, H.J. ; Chen, C. ; Field, J.H. ; et al.

Z.Phys.C 14 (1982) 283, 1982.

Inspire Record 177216 DOI 10.17182/hepdata.16414

The reaction (e+e−→μ+μ−) has been measured between$\sqrt S= 14.0$ and$\sqrt S= 36.4$. The total cross section result is in good agreement with the QED prediction and the following Λ values have been obtained:Λ+=186 GeV,Λ−=101 GeV. The angular distribution at high energy ($\left( {\left. {\left\langle {\sqrt S } \right.} \right\rangle= 34.2 GeV} \right)$) shows a fitted charge asymmetry of −0.064±0.064 in agreement with theW-S model prediction of −0.092, corresponding to an axial coupling parametera2=4ga2=0.69±0.69.

3 data tables

Table 1

No description provided.

Table 2

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Table 3

Errors include contribution from systematics. Result based on fit(1 + cos(theta)**2 + q cos(theta)) to corrected angular distribution.

Charge Asymmetry and Weak Interaction Effects in $e^+ e^- \to \mu^+ \mu^-$ and $e^+ e^- \to \tau^+ \tau^-$

The TASSO collaboration Brandelik, R. ; Braunschweig, W. ; Gather, K. ; et al.

Phys.Lett.B 110 (1982) 173-180, 1982.

Inspire Record 176719 DOI 10.17182/hepdata.6699

We have measured, at an average centre-of-mass energy of 34.22 GeV a forward-backward charge asymmetry in the reaction e + e − → μ + μ − of value −0.161 ± 0.032. This demonstrates the existence of an axial vector neutral current with coupling strength of g e a g μ a =0.53 ± 0.10. We have also obtained a limit on the vector coupling strength of g e v g μ v <0.12. The Weinberg angle is found to be sin 2 θ W =0.29 +0.09 −0.11 . From the reaction e + e − → τ + τ − we have found g e a g τ a <0.34, g e v g τ v <0.55.

7 data tables

Table 1

No description provided.

Table 2

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Table 3

No description provided.