Minimum Bias 1.5

A quick post to explain something about this, the first ATLAS physics results from LHC collisions at 7000 GeV.

The measurement is a repeat of the ATLAS minimum bias measurement at 900 GeV, except these protons hit each other at 7000 GeV, an energy 3.5 times higher than we ever managed before in an accelerator. (That link hopefully explains what “minimum bias” means.)

This is not a journal publication, it’s a “preliminary” measurement, to be presented at conferences. Hence the 1.5 in my title – we are working on 2.0, which is intended for a paper. But it is public, and it is useful to put it out there so it can be discussed by physicists who are not on ATLAS. And it does tell us something new.

Continue reading →

Posted in Particle Physics, Physics, Science | Tagged , | 6 Comments

This is Not a Drill

See also Chapter 3.2 of Smashing Physics.

I haven’t been paying as much attention as I should to science policy in the election. Guilty, will re-engage. I have a good excuse, of course. Even after STFC cuts we’re still members of CERN, the LHC is running, and (volcanoes permitting) I am traveling, working and basically doing physics. And it’s exciting and absorbing.

The wires of the ZEUS tracking chamber (credit T.J.Fraser)

Typical scientist. We just get the data and get happy. In STFC related politicking, I’ve heard our big mistake was that in economic good times, when science was getting roughly its share of the growth (and particle physics was getting somewhat less, but not being cut), we just shut up and got on with science.

It’s fair to say we should have said thanks (Thanks!), but this argument was that we should have been aggressively pushing for more & more cash, just so there was more fat to cut when bad times came. This shows a gulf in understanding between the worlds of science and politics, sadly.

Continue reading →

Posted in Particle Physics, Physics, Politics, Science, Science Policy | Tagged , , , | 3 Comments

Frog Chorus

See also Chapter 3.6 of Smashing Physics.

Last week, on the day we got our first 7 TeV collisions at the Large Hadron Collider, quite by chance we also had the conference dinner of the annual meeting of the Institute of Physics High Energy Particle Physics and Astroparticle Physics groups. After years of financial body-blows to the fields (both principally funded by the STFC in the UK), the LHC news made it a pretty cheerful meeting in the circumstances.

The man who headed the UCL high energy physics group when I was appointed to the faculty, Tegid Jones, gave a wonderful after dinner speech. He went through the true and sometimes untold stories around the start up of several big experiments he has been involved in. These included a water-filled proton decay detector in a salt mine (IMB) which initially leaked (dissolving quite a lot of the mine and almost drowning the thesis of a future congressman), then achieved a 300m 490m siphon effect with a cesspit on the surface (bad for optical purity of the water). After the third filling, they failing to find proton decay. However, they did observe neutrinos from Supernova 1987a – still the only observation of neutrinos from outside the solar system, at least until maybe ANITA spots one. It also developed a lot of the techniques taken forward by the experiments which eventually found neutrino oscillations.

I’m lucky to have been involved in the start of two major particle physics colliders. I was a student on the ZEUS experiment, on the HERA collider in DESY, Hamburg, when it began operation.

Continue reading →

Posted in Particle Physics, Physics, Physics Stories, Science | Tagged , , , , | 3 Comments

LHC High Energy Physics Start

See also Chapter 3.1 of Smashing Physics.

So, the LHC breaks new ground again. Not just in fundamental physics and accelerator technology, but in doing science live in public, or at least so it feels.

We had hoped for collisions for breakfast but it didn’t work out that way. The false starts reminded me of frustrating night-shifts on the ZEUS experiment in Hamburg where I did my PhD. They aren’t unusual on a new collider, but given the major accident in 2008, plus the huge public interest, it was a very nervous morning.

3.5 TeV collision

One of the first 3.5 TeV collisions in ATLAS

I guess this is how space scientists feel when launch delays happen in mid countdown. Injecting and ramping the beam energy feels like the initiation of a countdown sequence and we had to go through it three times before we finally launched the high energy physics programme of the LHC. For lunchtime. Good enough. Fantastic, in fact.

Continue reading →

Posted in Particle Physics, Physics, Science, Science Policy | Tagged , , , | 15 Comments