Friday, December 4, 2015

Still No New Physics At LHC

Lubos explains (with humor that is in somewhat bad taste as he allegorically compares the new physics theories that have been ruled out to terrorist mass shooting victims), that LHC Run 2 data from the CMS experiment have increased the range of masses for which various kinds of beyond the Standard Model hypothetical particles are ruled out by about 40% (on average) over the exclusions in place at the end of Run 1.

The Standard Model continues to explain all phenomena observed to within the error bars of the accuracy of the measurement after adequately accounting for look elsewhere effects.

The exclusions for the kinds of hypothetical particles searched for are for all such particles up to 2.6 TeV to 7 TeV, depending upon the type of particle in question, which is favor above the "Fermi scale" at which the heaviest electroweak fundamental particles are observed, but far below the GUT scale or Planck scale at which a unification of forces or fundamental limitations on energy scales might be encountered (which no human designed experiment has any realistic chance of ever reaching).

The exclusions will in all likelihood continue to grow larger as further data is collected at the LHC.


andrew said...

A parallel search at ATLAS concurs in the overall result.

Lubos states in a recent post that there is a rumor that a December 15, 2015 announcement will reveal a low significance diphoton excess at both CMS and ATLAS at around 700 GeV which could be a second Higgs boson resonance in his take on the data.

andrew said...

The rumor is reported here.

andrew said...

Quantum Diaries Survivor has a chart of recent ATLAS bump hunting. Basically, there is nothing really notable. The biggest bump is two sigma (and the visually most striking bumps are not statistically significant due to the low sample sizes and larger systemic errors at high energies involved more or less) and the significant once look elsewhere effects are considered is even lower.