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Interesting and optimistic Reuters report on prospects for next year

http://feeds.reuters.com/~r/reuters/sci ... QU20101115

Nice read Phil

Thanks

Has it been decided yet if they are going to ramp above 3.5 TEV. If yes, then what is the exact value please?

This is an interesting, almost philosophical problem:

Suppose that they decide to ramp to 4.0 TeV for example when they restart. As soon as the new "4.0" data starts to come in, then no theoritician will have any interest in analyzing the then obsolete "3.5" data. The net effect will be that most of the time spent on the 2010 "physics" runs would be lost, useless. This time would have been spent better if they had increased the field right away...

Of course, this is a little stupid since there was no way to know in advance that everything would work so well... Some "3.5" data is better than no data at all. I am sure they made the best choice.

My point is that the decision to restart the LHC at a REDEUCED energy after the crash was a BOLD decision. Almost as important as the decision to build this machine. If there was no chance to observe any new physics, then there was no need to spend many months taking data. I suppose that the same dilemma applies to the 2011 run.

amiso wrote:Suppose that they decide to ramp to 4.0 TeV for example when they restart. As soon as the new "4.0" data starts to come in, then no theoritician will have any interest in analyzing the then obsolete "3.5" data.

That's not true. At higher energies different kinds of collisions have different chances of happening but investigating certain kind of collisions (which all detectors can distinguish pretty well) does not depend on whether they came from 3.5 or 4.0 data.

Well, I suppose that they are still very interested by the high-energy-kind of collisions, if you see what I mean!

From what I have read on the web page:

** They will try to log as much data as possible for two years, then they will eventually stop for one year to upgrade to full capacity.

** They will try to maximize the data logging time, but if possible they will quickly increase the magnetic field to (safe) high energy setting.

** It is believed that the energy could safely be increased from 3.5 to 4 TEV.

The latest Reuters summary is at http://www.reuters.com/article/2011/02/ ... AQ20110209

The plan is to stay at 3.5TeV during 2011. There is still a possibility to increase energy to 4TeV during 2012 if ongoing measurements indicate that it is safe. Otherwise higher energies will not be seen until 2014 after the long shutdown. This year they will concentrate on increasing luminosity and run efficiency to get as much data as possible at 3.5TeV.

I think there are some misleading terms being used. I suspect when Reuters say 'energy' they mean 'intensity'.

The plans for 2011-12 as laid at out the Chamonix conference are to triple the number of bunches in the machine and double the squeeze.

An increase in energy above 3.5 TeV appears to have been ruled out as the potential return isn't worth the risk.

http://cdsweb.cern.ch/journal/CERNBulle ... es/1325053

No, Reuters got it right on this occasion - there is a possibility that the energy will be increased to 4TeV in 2012, energy increase has only been ruled out for 2011.

adam_jeff wrote:No, Reuters got it right on this occasion - there is a possibility that the energy will be increased to 4TeV in 2012, energy increase has only been ruled out for 2011.

I guess they also consider that in the unlikely case that something happens it wouldn't be as fatal as the first time and they would have sufficient amount of data collected already, so they could just start the upgrade. The 3/fb they may collect during 2011 could be enough to confirm or rule out Higgs at a nice band of energies.

The energy is fixed at 3.5 TeV for 2011. During the year there is a plan to develop a method to measure the resistance of the copper splices. If this can be done there would be a campaign of measurements during the next Christmas technical stop.

If the values are known then the energy can possibly be increased. There would not be an increased risk in this case - since it would be based on actual measurements instead of a statistical analysis. The assumptions in the present analysis are conservative, so that there is real hope that an increase in energy might be possible in 2012.

you'll have to wait and see ....

Thanks for that news pcatom, it's great to get info from a man who should know.

DCWhitworth wrote:Thanks for that news pcatom, it's great to get info from a man who should know.