First particles observed in Large Hadron Collider

August 26, 2008

( -- Glasgow scientists, working at CERN, have observed the first particles in the Large Hadron Collider during preliminary tests ahead of the switch-on next month.

The LHC, based at the European particle facility CERN near Geneva, is due to fully switch on its proton beams on 10 September but the LHC's particle detectors have been recording hits from cosmic rays for several months and at 5pm on Friday 22 August 2008 LHCb*, one of the four LHC experiments, reconstructed in its Vertex Locator (VELO) the first particles from the LHC. It is the first time particle tracks have been reconstructed from a man-made event generated by the collider.

The observation was made during a synchronisation test of the accelerator when the particles passed through a short section of the new 27km long LHC accelerator.

The LHC synchronisation test collided a beam of protons with a 28 tonne absorber 200m away from LHCb, producing a shower of particles. Some of these particles reached the LHCb experiment, where the tracks were observed by a small team of scientists. The observation was made with one quarter of the LHCb VELO detector operational on Friday 22 August. Given the success of this run, an additional sequence of beam collisions on the absorber were provided by the accelerator on Sunday morning and the full VELO detector was read out.

Professor Themis Bowcock (University of Liverpool), VELO Project Leader, said: “This achievement by the LHCb VELO – reconstructing the first tracks at the LHC - is a testament to the hard work and dedication of the team of scientists, who have worked on this detector for more than a decade.”

The VELO is a precise particle-tracking detector that surrounds the proton-proton collision point inside the LHCb experiment. At its heart are 84 half-moon shaped silicon sensors, each one connected to its electronics via a delicate system of more than 5000 bond wires. These sensors will be located very close to the colliding LHC beams, where they will play a crucial role in detecting b quarks, to help in understanding tiny but crucial differences in the behaviour of matter and antimatter.

Dr Chris Parkes (University of Glasgow), UK VELO Project Leader and VELO software co-ordinator, said: “The particles were seen by the team of scientists within seconds, and from the very first collision! This bodes well for the future operation of the experiment to explore the differences in behaviour of matter and anti-matter. ”

Dr Eddy Jans (Nikhef), VELO commissioning coordinator, said: “We had been preparing all week for this first chance to see tracks. In order to see these particles we had to setup the electronics to take the data at just the right time – and we got it correct to within 25 billionths of a second.”

The 27km long LHC accelerator and its four large experiments at CERN, with over 5,000 collaborating scientists, are currently in their commissioning stages. This observation of first particles from the beam, comes several weeks ahead of when the first collisions between the two beams are expected. The first beams to circulate around the complete ring are expected for 10 September, when over 200 journalists are expected to attend at CERN.

Dr Eduardo Rodrigues, a research assistant in the Glasgow LHCb group, and the LHCb VELO data quality co-ordinator said: “I had worked on the real-time monitoring plots which allowed us to see the particles traversing the detector. I was overwhelmed when we saw the evidence of the particle tracks clearly appearing on the computer monitors in the control room”.

Marco Gersabeck, a PhD student at the University of Glasgow, said: “It's working! And it is providing me with the type of particle tracks that I will use to align its sensors to an accuracy of a few millionths of a metre.”

UK scientists from the Universities of Glasgow and Liverpool have a major involvement with the Vertex Locator. The individual modules were designed and assembled in the UK. The reconstruction software used to observe these tracks was written by UK scientists. Nikhef provided the mechanics, cooling and vacuum system. Other collaborators are EPFL Lausanne, CERN, Syracuse University, Moscow State University, University College Dublin.

*LHCb - Large Hadron Collider beauty

The LHCb experiment will help us to understand why we live in a Universe that appears to be composed almost entirely of matter, but no antimatter.

It specialises in investigating the slight differences between matter and antimatter by studying a type of particle called the 'beauty quark', or 'b quark'.

Instead of surrounding the entire collision point with an enclosed detector, the LHCb experiment uses a series of sub-detectors to detect mainly forward particles. The first sub-detector is mounted close to the collision point, while the next ones stand one behind the other, over a length of 20 m.

An abundance of different types of quark will be created by the LHC before they decay quickly into other forms. To catch the b-quarks, LHCb has developed sophisticated movable tracking detectors close to the path of the beams circling in the LHC.

Like all the detector experiments at CERN a worldwide team of scientists are involved in the design and construction of LHCb. The experiment involves over 600 scientists from nearly 50 institutes and universities in 15 countries. UK collaborators make up around 20% of this.

The LHCb group at the University of Glasgow consists of: Dr Alison Bates, Dr Silvia Borghi, Mr Laurence Carson, Mr Fred Doherty, Dr Lars Eklund, Mr Marco Gersabeck, Dr Vava Gligorov, Ms Lena Haddad, Mr Franciole Marinho, Ms Fiona McEwan, Mr John J. Melone, Ms Michelle Nicol, Dr Chris Parkes, Dr Andrew Pickford, Mr. Barinjaka Rakotomiaramanana, Dr Eduardo Rodrigues, Dr Paul Soler, Dr Tomasz Szumlak.

The observation is reported on the Nature website:

Provided by University of Glasgow

Explore further: Large Hadron Collider: VELO -- in you go!

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3.7 / 5 (6) Aug 26, 2008
Come on Higgs!
4.8 / 5 (4) Aug 26, 2008
You know, as a physicist (ok, a grad student... but i'm working my way in that direction...), i think it'd be even more exciting for the LHC to cover the appropriate energies and NOT find the Higgs boson. Either way, tons of awesome fundamental physics will result. And, the need for a new "standard model" would be pretty interesting.
4.2 / 5 (5) Aug 26, 2008
Allow me to play devil's advocate: Higgs Boson = Ether
2 / 5 (2) Aug 26, 2008
I've read of a fair number of physicists saying similar things jrmontag. Some of them think it's pretty likely that the Higgs Boson will be found, but they think it would be really cool if it wasn't:).
Aug 26, 2008
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5 / 5 (1) Aug 26, 2008
This is exciting and I'm shocked that it's so quickly coming upon us.

I'd just like to see the background medium of the Universe established and gravity connected to electromagnetism, regardless of what they call it.
4.8 / 5 (4) Aug 26, 2008
the need for a new "standard model" would be pretty interesting

We already know we need a new standard model! Since it was coined as such. What would be really cool is something that is not predicted by any contending theories :) that way we would really have to scratch our heads! We need a paradigm shift in the sciences...although this is far fetched, it would be one of the coolest things ever. Higgs, Dark Matter, Dark Energy, Gravity...what are we really looking at? When every one in the world is going to be going "what the hell!" that would truly be an achievement and defiantly worthwhile. Go LHC!
5 / 5 (2) Aug 27, 2008
wow this new report came a bit sooner than i had expected.

Looks like soon something interesting is headed our way. Whether the Higgs is found(ie. Higgs boson/quanta verification of the Higgs field), or something even more intriguing... Perhaps something like a field with layered density gradients of varying surface tensions, that absorb/reflect correspondingly "sized" wavelengths(compton, etc), thus decohering superposition of it's surroundings given a certain "falloff". Anyhow
The LHC just inspires my imagination. Such a grand time to be a part of, IMO.
2.2 / 5 (9) Aug 27, 2008
Omg! Do you see what i see? It's not a bird or a plane, it's a micro black hole...coming our way! Run people run!

But seriously, it's just my eyelid.

Or is it?
4 / 5 (1) Aug 27, 2008
I wonder if the LHCb experiment will have any correlations with the other recently initiated searches for (things like)neutrinoless double beta decay, and its role in the balance of "matter/anti-matter" in our neck of th woods.(CP violation, majorana, neutrino/anti annihilation, etc)
4.7 / 5 (3) Aug 27, 2008
@phystic Neutrinoless double beta decay is primarily aimed at understanding the spin nature of the neutrino, technically if it is it's own antiparticle or not (Majarona vs Dirac). In terms of understanding the basic parameters of CP violation, the main experiments have been at the B factories (Cornell's CESR - no longer running; SLAC's BaBAR experiment - no longer running; and BELLE at KeK in Japan). The Fermilab Tevatron experiments are also publishing important measurements of b quark physics and topics related to CP violation, including studies of single top decays and observation of direct CP violation.
not rated yet Aug 27, 2008
Thanks LeeSawyer. :-) great reply. I've read of many scientists still posing the theory that neutrinoless double beta decay could be the cause of the dark/light matter balance in our universe(among other theories they hold equally viable). Seems stories postulating this notion(or others) come up very often in the news. Many of the reports i read are looking for more than "right-handedness", and rather the possible balance of matter in our universe.
For example, to neutrinos annihilate each other in double-beta-decay, then consider baryogenisis given sphaleron transitions arriving at a "light matter" bias in our region. looks like baryon and lepton number violation, although B%u2212L is conserved(or so it seems).
Just an idea, Though I'm still just learning myself.

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