Dear LHCb coleagues,

Indeed a major step. Given the size of teh data sample and the statistical relevance and earlier limits, I assume that the present result is in line with the Standard Model. If so a pity, but you can not command Nature and the qork behind this measurement is independent of whether the results is compatible or incompatible with the Standard Model. But I am sureall of you are eagerly awaiting an SM incompatible result!.

Once again: congratulations with a measurement of order one in a billion!

Best regards, Frank

On Mon, Nov 12, 2012 at 9:48 AM, Marcel Merk marcel.merk@nikhef.nl wrote:

Dear friends,

This morning a preprint was submitted to the arXiv with first (3.5 sigma) evidence of the decay Bs->mumu as well as a first determination of the branching ratio. I am particularly proud of this result since our Nikhef group has made central contributions to:

• Theory: together with our Nikhef theory friends we addressed the time

integrated vs "t=0" BR.

• fs/fd fragmentation: a leading systematic input for the Bs->mumu BR

extraction

• the selection and background study for Bs->mumu.

Congratulations to all people involved!

Cheers,

• Marcel