Measurement of the $K^+\toπ^+ν\barν$ Branching Ratio

The E949 Collaboration

doi:10.1103/PhysRevD.77.052003

paper

Measurement of the $K^{+} \to π^{+} ν ν ˉ$ Branching Ratio

arXiv:0709.1000 · doi:10.1103/PhysRevD.77.052003

Abstract

Experiment E949 at Brookhaven National Laboratory studied the rare decay $K^+\toπ^+ν\barν $an d o t h er p r ocesses w i t han e x p os u r eo f$ 1.77\times 10^{12}K^+ $^{'} s . T h e d a t a w er e ana l y z e d u s in g ab l in d ana l y s i s t ec hni q u ey i e l d in g o n ec an d i d a t ee v e n tw i t han es t ima t e d ba c k g r o u n d o f$ 0.30\pm0.03 $e v e n t s . C o mbinin g t hi sr es u l tw i t h t h eo b ser v a t i o n o f tw oc an d i d a t ee v e n t s b y t h e p r e d ecessor e x p er im e n tE 787 g a v e t h e b r an c hin g r a t i o$ {\calB}(K^+\toπ^+ν\barν)=(1.47^{+1.30}_{-0.89})\times 10^{-10} $, co n s i s t e n tw i t h t h e S t an d a r d M o d e l p r e d i c t i o n o f$ (0.74\pm0.20)\times 10^{-10}$. This is a more detailed report of results previously published in Physical Review Letters.

99 pages, 32 figures, 12 tables. Added authors, corrected typos and modify the text suggested by the referees. Accepted for publication in PRD

Measurement of the K+→π+ννˉ Branching Ratio

Abstract

Measurement of the $K^{+} \to π^{+} ν ν ˉ$ Branching Ratio