Thursday, March 23, 2017

Still No Evidence Of SUSY

Supersymmetry (i.e. SUSY) is not supported by any experimental evidence that distinguishes it from the Standard Model, and the exclusions are far above the weak scale where it was expected to manifest itself. 
This week results are being presented by the LHC experiments at the Moriond (twitter here) and Aspen conferences. While these so far have not been getting much publicity from CERN or in the media, they are quite significant, as first results from an analysis of the full dataset from the 2015+2016 run at 13 TeV, This is nearly the design energy (14 TeV) and a significant amount of data (36 inverse fb/experiment). The target for this year’s run (physics to start in June) is another 45 inverse fb and we’ll not start to hear about results from that until a year or so from now. For 14 TeV and significantly larger amounts of data, the wait will be until 2021 or so. 
The results on searches for supersymmetry reported this week have all been negative, further pushing up the limits on possible masses of conjectured superparticles. Typical limits on gluino masses are now about 2.0 TeV (see here for the latest), up from about 1.8 TeV last summer (see here). ATLAS results are being posted here, and I believe CMS results will appear here.
From here.

In other news from these conferences in progress, there are no newly announced Higgs boson mass or width results, and the experimentally measured fit of the observed Higgs boson couplings to those predicted by the Standard Model remains very tight (comfortably within one standard deviation of the expected value overall).

No significant BSM physics of any kind has been observed definitively at the LHC, although a handful of moderate significance anomalies have been noted that might or might not amount to anything. None of the anomalies are easy and obvious fits to popular BSM theories akin to SUSY.

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