A Search for the Decay $B^{-}\to K^{-} ν\barν$

B. Aubert

paper

A Search for the Decay $B^{-} \to K^{-} ν ν ˉ$

arXiv:hep-ex/0304020

Abstract

We present a search for the rare flavour-changing neutral-current decay $B^{-} \to K^{-} ν ν ˉ$ based on a sample of $(86.9 \pm 1.0) \times 1 0^{6}$ $Υ (4 S) \to$ B\bar{B} $e v e n t sco l l ec t e d b y t h e B A B A R e x p er im e n t a tt h e S L A C B - f a c t or y . S i g na l c an d i d a t ee v e n t s a r ese l ec t e d b y f u l l y r eco n s t r u c t in g a$ B^+ \to \bar{D}^{0} X^+ $d ec a y, w h er e$ X^+ $r e p r ese n t s a co mbina t i o n o f u pt o t h r eec ha r g e d p i o n sor k a o n s an d u pt o tw o$ π^0 $c an d i d a t es . T h ec ha r g e d t r a c k s an d c a l or im e t er c l u s t er s n o t u se d in t h e$ B^+ $r eco n s t r u c t i o na r er e q u i r e d t o b eco m p a t ib l e w i t ha$ B^{-}\to K^{-} ν\barν $d ec a y . W eo b ser v e a t o t a l o f t h r ees i g na l c an d i d a t ee v e n t s w i t han e x p ec t e d ba c k g r o u n d o f$ 2.7 \pm 0.8 $, r es u l t in g ina p r e l imina r y l imi t o f$ \mathcal{B}(B^{-}\to K^{-} ν\barν) < 1.05 \times 10^{-4} $a tt h e 90$ B^{-}\to K^{-} ν\barν $t o g i v e a l imi t o f$ \mathcal{B}(B^{-}\to K^{-} ν\barν) < 7.0 \times 10^{-5}$ at the 90% confidence level.

Presented at XXXVIII Rencontres de Moriond on Electroweak Interactions and Unified Theories

A Search for the Decay B−→K−ννˉ

Abstract

A Search for the Decay $B^{-} \to K^{-} ν ν ˉ$