Not Even Wrong

Things evidently went extremely well over the weekend at the LHC, with simultaneous circulating beams achieved this morning. Speculation is that first collisions (at the injection energy of 450 GeV/beam) are imminent. Places for up to the minute information include here, here and here.

Update: It looks like first collisions have been seen at the LHC. Announcement comes from a muzzled blogger….

Update: Modified posting title.

This past winter a combined analysis of data from the two Tevatron experiments showed at 95% confidence level that the Higgs mass could not be in the range 160-170 GeV. This was a better result than expected: statistically the experiments should not have been able to exclude any of the mass range, but were helped by a downward statistical fluctuation.

Today a new and improved combined analysis was released using more data, and the new result is that there has been a reversion to the mean, no more help from statistical fluctuation downwards. Statistically, this time they should have been able to exclude 159-168 GeV, but now the fluctuation is a bit upwards, so the actual exclusion region is 163-166 GeV. In essence, better data has shown that the likelihood of a 160-163 or 166-170 GeV Higgs, something that was previously assigned a probability of a bit less than 5%, now has a probability a bit more than 5%. So, any putative Higgs particle in those mass regions has now escaped being tarred with the unfair label of “excluded”.

If the Higgs is actually there at a certain mass, as one gets closer and closer to having sufficient data to exclude its existence, one should find oneself doing nowhere near as well as expected as far as excluding that mass. A thoroughly irresponsible person might see some significance in the fact that, unlike the analysis from earlier this year, the new improved analysis with more data does a worse job of exclusion than expected over much of the low mass range, peaking at 1.5 sigma or so for the mass range around 135 GeV.

Update: More detail and rank speculation about this from Tommaso Dorigo here.

Yesterday the LHC Hardware Commissioning Coordination Team announced the end of the 2009 Hardware Commissioning Campaign as all 8 LHC sectors were declared commissioned and ready for beam. A two day checkout period is now underway, which should have the LHC ready for beam at 17:00 Friday. Friday evening and night should see beams threaded around the machine in both directions. Saturday the plan is to capture a circulating beam in one direction, Sunday in the other direction. Celebratory drinks are scheduled for 17:00 Monday in the CERN Control Center.

Update: Up-to-date news about beam commissioning is here, and hopefully CERN won’t shut off outside access to it. Normally I try and avoid providing links that might be in danger of becoming non-public, but in this case, since the New York Times is linking to this, I suppose I should too.

Update: The LHC Portal is a site with a lot of links to CERN information. For more about the site, see here.

Update: Beam is in the LHC and has made it part way around, to IP3. One place to follow progress is here.

Just as I finished writing that, I see it’s now at IP5.

Update: After a short stop to recover from a magnet quench, the beam has now gone all the way around the ring, making two turns.

The latest official news from CERN about the LHC schedule that I’ve seen is this from DG Rolf Heuer, who doesn’t give specific dates other than “second half of November” for circulating beams, collisions at injection energy soon thereafter, and, if all goes well, “high-energy collisions” before Christmas. He doesn’t specify what the value of “high-energy” is.

Physics Today has this story, which has a lot more detail than available officially, including a quote described as “a statement on the CERN web-site”:

This means that 2009 will not see physics collisions, but will perhaps see collisions at energies marginally higher than that of the Tevatron…

which was picked up by the New York Times here, and reported as:

The lab now says the first collisions, before Christmas, will be even lower, due to delays in finishing a system to protect the powerful superconducting magnets from explosive failures. The initial collisions will be at 1.1 trillion electron volts per beam, just barely above the energy of the Tevatron collider now running at CERN’s rival, the Fermi National Accelerator Laboratory outside Chicago.

I can’t find that quote on any CERN site, but it and the other details of the story do seem awfully familiar.

Unofficially, what’s known about the schedule at the moment is:

Next weekend (Nov. 7-8): Second injection test. If sector 67 is ready, beam will travel through this sector (and possibly even through sector 56) as well as the two (sectors 23 and 78) tested during the first injection test.

November 20th: First attempt to circulate beams at the injection energy of 450 GeV.

Early December: Collisions at 450 GeV.

Mid-December: Ramp to 1.1 TeV, collisions at 1.1 TeV/beam.

December 16th: Stop of beam commissioning for end-of-year break.

January 4: Restart after end-of-year break. About three weeks for hardware commissioning to 6kA, 3.5 TeV/beam.

Late January: Beam commissioning at 3.5 TeV/beam.

Early February: Collisions at 3.5 TeV/beam. First physics run soon thereafter.

Update: Not sure what to make of this. At first I found this hard to believe, but there’s another story here.

Update: I guess this actually happened: here’s something from CERN.

Update: Looks like they will be able to get a beam through 4 of the LHC’s 8 sectors this weekend.

Commenter Yatima points to this at the Register. If you believe the Register (not necessarily a good idea…), CERN’s Sergio Bertolucci is promoting the idea that the LHC will open a portal to other dimensions, so:

Summarising, then, it appears that we might be in for some kind of invasion by spontaneously swelling and shrinking spherical or wheel-shaped creatures – something on the order of the huge rumbling stone ball from Indiana Jones – able to move in and out of our plane at will. Soon the cities of humanity will lie in smoking ruins, shattered by the Attack of the Teleporting Juggernaut-tyrants from the Nth Dimension.

The writer asks LHC Machine Coordinator Mike Lamont what he thinks of all this. He suggests reading Lisa Randall’s book.

Last week there was a meeting of HEPAP held in Washington, presentations are available here.

HEP has done very well recently in recent US federal government budgets, due to the stimulus and large deficit spending going on to fight the recession. The FY2010 DOE budget has been passed by Congress, and it includes $810 million for HEP (up 2% from $797 million in FY2009), and there is also $232 million in stimulus package money currently being spent on HEP. The FY2010 NSF budget has not yet made it through Congress, but the Administration request for NSF physics research is up by 9% from FY2009.

DOE is planning to keep running the Tevatron now at least through FY 2011, since it is likely to be competitive with the LHC in the Higgs search business at least that long. The current Fermilab long-term planned run schedule is here.

DOE will keep supporting ILC research through FY2012, but the plan to make a decision about building it at that time now seems to be off the table. The LHC will have just begun producing results, and the current estimates of the ILC cost are so high that making the case for it will be very difficult. A story in Science quotes William Brinkman, the head of DOE’s Office of Science as saying:

With all the contingencies, you’re talking about $20 billion. In my opinion, that price pushes it way out into the future, and onto the backburner.

Funding for new high-energy accelerators is likely to mainly be devoted to participating in any upgrade of the LHC at CERN, and the Project X/muon collider proposals at Fermilab. There will be workshops at Fermilab next month to discuss Project X and the muon collider. Brinkman in his HEPAP talk notes that the HEP community will have to come up with a compelling scientific case for these projects, which will largely revolve around an expanded neutrino program.

There was also discussion of a report from PASAG (the Particle Astrophysics Assessment Group). For discussion of the issues surrounding proposed experiments relevant to particle astrophysics and cosmology, see stories from Eric Hand at Nature News here and here.

This weekend successful tests of injection of a beam from the SPS into the LHC were performed. The beam only traveled through a few of the sectors before being dumped, since all sectors of the machine are not yet ready for beam commissioning.

A week or so ago the decision was made to start beam commissioning with the magnets only fully commissioned to 2kA. This means that the machine will be limited to operation at 1.1 TeV/beam this year. The current schedule has commissioning to 2kA finishing November 16, attempts to circulate 450 GeV beams starting November 23. On December 7, the beam energy would start to ramp up to 1.1 TeV. 1.1 TeV/beam collisions would start Dec. 14, with shutdown for Christmas/New Year’s starting Dec. 16. This means that 2009 will not see physics collisions, but will perhaps see collisions at energies marginally higher than that of the Tevatron.

By the end of the year, 2 sectors will be commissioned to 6kA, the magnet current needed to run the machine for physics at 3.5 TeV/beam. The rest of the sectors will be commissioned to 6kA and the energy ramped up to 3.5 TeV/beam starting after the shutdown ends in January.

Update: Some more from the latest schedule. January 7 will be the start of recommissioning after the shutdown, and current plan is to have the machine ready for physics collisions at 3.5 TeV/beam by February 8.

Update: The date to begin beam commissioning again by circulating a beam in the LHC is now set for Friday November 20.

Things have been going fairly well at the LHC, with no major problems encountered recently as the machine is being prepared for operation. The last two sectors (34 and 67) are almost cool (see more about this here). Not mentioned in the CERN Bulletin article is that there has been about a week and a half slippage with respect to the schedule of a month ago, with the current schedule having powering tests finishing in the last two sectors around November 20. Attempts to circulate beams and begin the beam commissioning process should begin shortly after that.

CERN has also recently decided how to handle the media campaign for this second attempt to start up the machine. Unlike last year, there will be no media event associated with the first circulation of beams, just press releases issued at that time, at the time of first collisions at 450 GeV, and at the time the beam energy is raised to a world record (above that of the Tevatron, 1 TeV). There will be a media event planned for first collisions at 3.5 TeV/beam, but the date for this will only be planned about 2 weeks before it happens, and confirmed a day or two before the event. It’s possible that this will happen later in December, just before the holiday shutdown, but maybe it’s more likely for January. CERN has a web-site set up for the media on this topic, see here, where all they say “The first high energy collisions will most likely occur at a date after mid-December 2009.”

In other LHC news, there has been an ongoing campaign to simulate the bad interconnections that are still known to be there in the machine, and these simulations have led to much more confidence that the potential dangers in the case of a quench are understood. The simulations show that operation at 3.5 TeV/beam should be safe, but going up to 5 TeV/beam without fixing the interconnections (which requires warming up the sectors involved) still seems risky.

Things seems to have been going well at the LHC recently, with the current schedule expecting injection of beams in a little more than two months from now, on Thursday November 19. After that, the plan is for a week and a half of beam commissioning at 450 GeV, and 450 GeV collisions at the beginning of December. The machine will then be ramped up to first 1 TeV, then 3.5 TeV, with 3.5 TeV collisions on December 14.

Soon after that (December 17), the machine will go into a technical stop period for the holidays, starting back up January 7. From then on, the plan is for a month of more commissioning work and pilot physics. The first regular physics run at 3.5 TeV will last about 3 months, with expected luminosity of 54 pb^-1. Then in May, the energy will be increased to somewhere in the range of 4-5 TeV, with a run beginning in June at that energy lasting until mid-October, with expected luminosity of 274 pb^-1. The machine will then be reconfigured for a one-month run with heavy ions, and then go into a long shutdown at the end of November.

Anyway, that’s the latest plan, reality may turn out differently. For up to the minute information on how things are going, you can follow along here. The last sector to be ready is now supposed to be sector 67, which is in cooldown, the magnets currently around 200K.

See here for a recent Science Magazine story on the subject from Adrian Cho.

Here’s an announcement from the CERN DG Rolf Heuer sent out to CERN employees today:

The foreseen shutdown work on the LHC is proceeding well, including the powering tests with the new quench protection system. However, during the past week vacuum leaks have been found in two “cold” sectors of the LHC. The leaks were found in sectors 8-1 and 2-3 while they were being prepared for the electrical tests on the copper stabilizers at around 80 K. In both cases the leak is at one end of the sector, where the electrical feedbox, DFBA, joins Q7, the final magnet in the sector.

Unfortunately, the repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector “floats” in temperature and the remainder of the sector is kept at 80 K. As the leak is from the helium circuit to the insulating vacuum, the repair work will have no impact on the vacuum in the beam pipe. However the intervention will have an impact on the schedule for the restart. It is now foreseen that the LHC will be closed up and ready for beam injection by mid-November.

This is an extra two week or so slip with respect to the latest draft schedule I’d seen. In addition, the question of how to deal with defective splices remains open. Efforts now are directed towards determining what the maximum safe energy is, assuming that the cold sectors are not warmed up, with the plan to have an answer to this question by the second week of August. Part of this effort involves study of possible changes in the parameters that determine how quenches are detected and dealt with, in order to optimize the maximum safe energy.

Update: The latest CERN Bulletin is out, with more about this.