Determining the sign of the Z-penguin amplitude

Journal article

We point out that the precision measurements of the pseudo observables Rb0, Ab, and AFB0,b performed at the CERN LEP and the Stanford Linear Collider suggest that in models with minimal-flavor violation the sign of the Z-penguin amplitude is identical to the one present in the standard model. We determine the allowed range for the nonstandard contribution to the Inami-Lim function C and show, by analyzing possible scenarios with positive and negative interference of standard model and new physics contributions, that the derived bound holds in each given case. Finally, we derive lower and upper limits for the branching ratios of K+→π+νν̄, KL→π0νν̄ , KL→μ+μ-, B̄→Xd,sνν̄, and Bd,s→μ+μ- within constrained minimal-flavor violation, making use of the wealth of available data collected at the Z pole. © 2007 The American Physical Society.

Authors: Haisch, U; Weiler, A

• Publication status: Published
• Journal: Physical Review D
• Volume: 76
• Issue: 7
• Publication date: 2007-10-01
• DOI: 10.1103/PhysRevD.76.074027
• EISSN: 1550-2368
• ISSN: 1550-7998
• Language: English