# I Decay of the Bs0 particle and supersymmetry

1. Feb 16, 2017

### kodama

14 February 2017: First single experiment observation of the decay Bs0→ μ+μ-.
From discovery to precision measurement.
[ Branching fraction Bs0→ μ+μ- = (2.8±0.6)x10-9 ; B0→ μ+μ- < 3.4x10-10 ]

"“We love this decay because it is one of the most promising places to search for any new effects of supersymmetry,” Archilli says. “Scientists searched for this decay for more than 30 years and now we finally have the first single-experiment observation.”

the decay and lifetime is accord with SM predictions

how does supersymmetry effect decay in precision measurements and how many standard deviations does supersymmetry effects differ from SM, and from LHCb results?

2. Feb 17, 2017

### Staff: Mentor

Nice to see that result.

$B^0 \to \mu \mu$ was a bit above the SM expectation in previous results, now it is closer to the SM prediction again.

The predictions with supersymmetry cover the whole interesting range, sometimes even values below the SM prediction. You cannot rule out supersymmetry that way, but it narrows down the parameter range a lot.

3. Feb 17, 2017

### kodama

any specific details, esp in combination with other constraints from other measurements supersymmetry? is MSSM or nMSSM still viable, or does something like nnMSSM is needed?

4. Feb 17, 2017

### Staff: Mentor

You can find specific details in the specific publications of your favorite SUSY model.

5. Feb 20, 2017

### kodama

what is your favorite SUSY model? one that survives all previous constraints ?

any SUSY rumors on 2016 LHC run?

6. Feb 20, 2017

### Staff: Mentor

My favorite SUSY model is no SUSY.

Every experimental evidence for BSM physics would be better than no such evidence, no matter which theory it supports, but until we have such evidence I don't care much about SUSY. It is just too flexible with its 1xx free parameters.

7. Feb 20, 2017

### kodama

has there been any rumors of any bsm about the 2016 lhc run, some 40 fb-1? when will results be announced?

8. Feb 20, 2017

### Staff: Mentor

First results are expected by Moriond in March. I can't (and don't want to) comment on rumors.

9. Feb 20, 2017

### kodama

March is only a few weeks away. will results reflect analysis of the full 2016 40 fb-1 plus 2011-2015 data, or only a small fraction of 2016 results?

10. Feb 21, 2017

### Staff: Mentor

We had a small fraction of 2016 data for ICHEP in August already.

Most searches will probably use the full 2016 dataset (+2015). It doesn't make much sense to publish results now that are based on a part of the 2016 dataset. If the analyses are not done yet, the results will be shown later. More complex analyses need more time.