Posted: September 10, 2008
At around 09:20 this morning the first beam of particles injected into the Large Hadron Collider successfully completed its maiden voyage around the 27 kilometre track that makes up the world’s biggest ever physics experiment.
Recreating conditions that existed billionths of a second after time began, four giant experiments – ALICE, ATLAS, CMS and LHCb – will search for signs of new physics such as the elusive Higgs particle that is thought to hold the clues to the existence of mass. The experiments will also probe extra dimensions, and investigate the nature of dark matter, and indeed all matter that makes up the Universe.
Astronomy Now Assistant Editor Kulvinder Singh Chadha talks to Professor Jordan Nash of Imperial College London about the LHC.
“Now comes a day of reckoning,” LHC project leader Lyn Evans said while he waited for evidence of the particle beam to appear on his computer screens at CERN (the European Organisation for Nuclear Research) headquarters. “Three – Two – One – there it is,” he confirmed over the background of cheers. While the LHC project managers remained in the control room at CERN, contributing scientists from the UK, and the media, assembled in Central Hall, Westminster for a live link-up to CERN.
The proton beam – travelling around the underground tunnel in a clockwise direction – took less than an hour to complete its first circuit, but when the LHC is operating at full power, the protons will make over 11,000 circuits in just one second, guided by thousands of magnets and accelerated by electromagnetic forces. Eventually two proton beams will be steered in opposite directions at almost the speed of light, and at allotted points around the tunnel – the locations of the four main detectors – the beams will cross paths, smashing together while the detectors observe the subatomic debris which may hold the key to some of the Universe’s deepest secrets.
Secretary of State John Denman said he was “delighted and excited” by the work that CERN had achieved, demonstrating the “scale of ambition and consistent vision of the people working at CERN.” The idea of the LHC was conceived in the early 1980s and was eventually approved in 1996. Over ten years later and all the hard work has paid off, as particle physics embarks on a journey of exploration like none before.
The media joined scientists involved in the LHC project at an STFC organised press event held at Central Hall in Westminster this morning.
Dr Valerie Gibson from the Cavendish Laboratory at Cambridge University works on the LHCb detector, the aim of which is to find out why the Universe is made of matter and not antimatter. Existing theory says that there were equal amounts of matter and antimatter at the big bang, but if that were the case nothing would exist since antimatter and matter annihilate each other. The LHC will help find out why matter came to rule the Universe. “I’m delighted to see the beam working,” she says. “It’s the accumulation of around 20 years of work for many people.”
Cambridge University is also involved in the so-called “big discovery” experiment ATLAS which will be looking for black holes and extra dimensions. “[The turn-on] went incredibly smoothly,” says Professor Andy Parker who is working on the ATLAS detector. “We even got the first data out of our experiment ATLAS. We saw the beam particles coming through and we’re seeing stuff that looks sensible.”
Professor Andy Parker of Cambridge University proudly shows off the first light results from the ATLAS detector, emailed to him straight from CERN. The graphics show the paths of the protons as they passed through ATLAS.
Parker described how ATLAS will work once the LHC is running at full power: “As the particles come flying through the detectors and collide we’ll measure their tracks, their energies and their components after collision. We’ll reconstruct what happens in the collision to try and understand the forces that operate in nature and what matter is made of.” He likens the development of the theories that the LHC will addresses to our earlier discoveries of ‘theories’ like electromagnetism. “Only after discovering electricity and magnetism could we make radios, electric motors, telescopes and develop communications… Someone figured out how it all worked. On the matter side, nuclear power came about because we understood how atoms were put together, and the LHC is just the next step in our understanding.”
He told Astronomy Now: “Our progress as a species is because we’ve always been curious. We look around at what there is and we find out how to manipulate it. We’re just doing the same again with the LHC, finding out what’s there.”
Students from the Langton Star Centre in Canterbury enjoyed a trip to CERN which has inspired some of them to take up physics at university. One of the students commented: “what you experience in the class compared to going out and experiencing physics first hand is very different.” Another student said that he hoped that as well as accelerating protons, the LHC will accelerate young people’s interest in science.
By lunchtime today a second beam was running in an anti-clockwise direction, an important milestone in the experiment’s journey that marks the end of the building of the LHC and the dawn of a new era of particle physics.
"The LHC will pave the way for the next generation of scientists to explore the fabric of the Universe," said a spokesperson from STFC. The UK government has invested more than £500 million in the construction of the LHC, which in total has cost over £5 billion.
It is expected that the first LHC particle collisions will occur before the giant machine powers down for the winter.
To find out more about the science behind the LHC, read our article on Powering up the world’s biggest physics experiment.