Day 5: Plenary sessions (again!)

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DIS 2012 wrapped up today, and the last day of the conference was filled with another round of plenary sessions (attended by everybody). This time, though, the talks were mostly devoted to summarizing the parallel sessions which took place over the previous three days.

The conference was divided up by topic into seven working groups: structure functions, the future of DIS, diffraction and vector mesons, electroweak and new physics searches, hadronic final states, heavy flavor, and spin physics. Each of these working groups was organized by two or three conveners, who were also responsible for putting together and presenting the summary slides. I have to recognize the impressive amount of work this must have taken: in one afternoon, the conveners went through every single presentation given in the conference, and organized and adapted the main conclusions from all of them into an experimental and a theoretical summary talk for each working group. Not to mention they had to stay awake and attentive for the entire three days of talks — much easier said than done!

Anyway, the full summary presentations can be found on Indico, so if you’re interested, go ahead and check those out. I’ll post a more detailed summary, or perhaps multiple summaries, once I have some time to go through the presentations again (perhaps in a few days when I recover high-speed internet access), but for now, I just wanted to highlight a few key developments:

  • LHC data is starting to dominate the input for various sorts of theoretical calculations, including constraints on the mass of the weak boson, the coupling constants of the standard model, and parton distribution functions (which describe the structure of the proton), among other things. Several of the groups which calculate these parton distribution functions will shortly be releasing updated numbers which take the 2011 LHC data into account.
  • The first collisions in the LHC at \(\SI{8}{TeV}\) actually took place today!
  • Although the Tevatron is shut down, analysis of its data is still yielding interesting results, especially with respect to the nature of parity violation in the weak force. Since the Tevatron collided two beams of different particles, it’s well-placed to look for these parity violations (as opposed to the LHC, where the two beams are the same and thus most parity violations are hidden).
  • The COMPASS experiment continues to produce data which is very useful for analyzing the spins of constituents of the proton.
  • We’ve known for a while now, but the Higgs boson is excluded at \(2\sigma\) (95% chance that it doesn’t exist) outside of two narrow ranges, a \(\SI{1}{GeV}\)-ish range around \(\SI{118}{GeV}\) and a \(\SI{5}{GeV}\) range around \(\SI{125}{GeV}\). (I might be a tiny bit off on the numbers, I forgot to write them down as they came up)
  • Pretty much everything still agrees with the standard model (so, no big experimental surprises).
  • Future plans for the LHC include two upgrades to the luminosity over the next 10 years or so, and also — if the plans are approved — the addition of an electron accelerator to form the LHeC, Large Hadron-electron Collider. This new machine will enable a whole host of new physics experiments that are impractical or impossible using the current LHC.
  • In addition, there is a long-term plan to build the EIC (Electron-Ion Collider) to complement the LHeC.

Finally, although it didn’t actually happen at this conference, we did find out today that the OPERA experiment has tentatively adjusted their analysis to account for the equipment errors they discovered earlier, and the new time-of-flight discrepancy is \(\delta t = -1.7\pm 3.7\ \si{ns}\), which is perfectly consistent with relativity. I’ll be writing more about this tomorrow, but for now Matt Strassler has a post on it which will surely be updated with additional details.