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CERN Confirms Hints of Hypothetical Particle Have Disappeared (arstechnica.com)
John Timmer, writing for Ars Technica: Toward the end of last year, the people behind the Large Hadron Collider announced that they might have found signs of a new particle. Their evidence came from an analysis of the first high-energy data obtained after the LHC's two general-purpose detectors underwent an extensive upgrade. While the possible new particle didn't produce a signal that reached statistical significance, it did show up in both detectors, raising the hope that the LHC was finally on to some new physics. This week, those hopes have officially been dashed. Physicists used a conference to release their analysis of the flood of data that came out of this year's run. According to their data, the area of the apparent signal is filled by nothing but statistical noise. The search for new particles in data from the LHC starts with a calculation of the sorts of things we should expect to see at a given energy. The Standard Model, which describes particles and forces, can be used to make predictions of the frequency at which specific particles will pop out of collisions, as well as what those particles will decay into. So, for example, the Standard Model might indicate that two electrons should appear in five percent of the collisions that occur at a specific energy. Looking for new particles involves looking for deviations from those predictions.
Well, they already did discover one new particle. The one they call the Higgs.
If they never again find anything new with LHC, that will at least direct theoretical physicists to new directions by invalidating all the theories that rely on new particles.
By excluding the existence of particles with certain properties, LHC eliminates some theories and that has real scientific value. In a sense the "value" of the measurements is in how different they are from theory. If LHC had NOT see a Higgs boson, that in many ways would have been more interesting than their having see one. Since the most widely accepted theories predicted a Higgs, showing that it didn't exist (within the range of expected properties) would have been very interesting. That would be similar to the Michelson Morley experiment which expected to find the "ether" but didn't.
It turns out that LHC saw the Higgs, but so far nothing else new. Since that was expected, it is not very exciting but its still useful science.
The great majority of science experiments find was was expected. The are good experiments, but its the few lucky ones that find a surprise that are most interesting.
The CMS experiment which I am on - only one of the several LHC experiments - went to just this conference being mentioned with ~80 new analyses. These analyses are measurements of particle properties to a greater precision, or explorations of previously unknown territory. Many of these will later be turned into papers and add on the already >400 journal papers by our experiment. Even neglecting the Higgs boson discovery, the scientific output and acquired new knowledge from the LHC has already been immense.