Mammoth experiments are under way to test various theories of particle physics. The next stage of experiments is expected to help us understand subatomic particles
On June 3 this year, billions of collisions occurred in a 27-km-long circular tunnel between Switzerland and France. But this is not a cause for concern as these collisions were part of the second season of experiments at CERN (the European Organization for Nuclear Research), which is the world’s leading laboratory for particle physics.
The first season of collisions at eight TeV (teraelectronvolt) confirmed the presence of Higgs boson, the elusive particle that seems to provide mass to all other particles. In the second season, proton beams will be made to collide at 13 TeV, nearly double the energy at which experiments were carried out in the first season. Researchers hope these experiments would further increase our understanding of subatomic particles. By releasing the beams of protons into the Large Hadron Collider (LHC) in both directions, and controlling them with powerful superconducting magnets, the researchers managed to generate stable beams. Researchers now have a source for a truly new set of data. “Let’s see what they will reveal to us,” says Rolf Heuer, director-general of CERN.
When protons with high energy collide, they fragment into the most basic of its components. These are being detected by sensors placed around the LHC. “It is a big jump from eight TeV to 13TeV. Particles could behave one way at eight TeV and in another way at 13 TeV,” says Varun Sharma, a PhD student at CERN. Sharma works on the Compact Muon Solenoid (CMS), one of the seven particle detectors that helps see the subatomic particles produced during the collisions. Sharma is hoping to study the sub particles of quarks—one of the fundamental particles in physics. These sub particles or preons have been discussed theoretically and their presence would be confirmed if their signature can be detected.
During the second season, seven experiments are planned. Detectors ATLAS, CMS, ALICE and LHCb will look at a wide range of physics phenomena—from Higgs boson and dark matter to the difference between matter and antimatter. Experiments like TOTEM would use detectors to measure the protons as they emerge from collisions. The LHCf experiment would measure neutral particles. The MoEDAL experiment would look for magnetic monopoles to investigate the possibility of extra dimensions and the nature of dark matter. (see box: ‘Data scope’)
| DATA SCOPE
Invisible and makes up most of the universe. We can detect it only from its gravitational effects on visible matter
An offshoot of the Standard Model and aims to fill in the gaps in the model. It suggests each particle in the Standard Model is accompanied by another particle
QUANTUM BLACK HOLES:
Miniature versions of the black holes which have a strong gravitational pull
One of the theories to explain the origin of the universe. According to this, all matter in the universe was formed in a single explosive event 13.7 billion years ago
“We strongly believe that something unknown is just around the corner,” says Ehud Duchovni of Weizmann Institute of Science, Israel. This makes the research an exciting adventure, he adds. Michael Hance, a researcher at the Lawrence Berkeley National Laboratory in the US, who works on the ATLAS experiment, is looking at events with bosons that may come from the decay of some heavy new particle. “During the first-run of the LHC, we searched for evidence of physics beyond the Standard Model but unfortunately, we did not see convincing signs of anything new. During the second season, we hope to find outside of what the Standard Model predicts. This could be a new particle or a new force of nature,” says Hance.
“The universe is composed of approximately 68.3 per cent dark energy, 26.8 per cent dark matter and 4.9 per cent ordinary or visible matter. What we know about the universe belongs to the last 4.9 per cent,” says Brajesh Choudhary, professor, department of physics and astrophysics, University of Delhi. “The field of research is wide open when it comes to the remaining aspects of fundamental physics,” he adds.
Huge amounts of data would be generated during the second season—150 million sensors are taking images 40 million times per second. “This is just the beginning,” says Markus Schulz, who works on distributed computing at CERN. The quantum of data generated is expected to increase from 25 peta bytes (PB) per year in 2012 to 400 PB per year by 2024, providing scientists a wealth of information to enrich our understanding of the universe. While it is not yet clear how the “new physics” would help in precise terms, the research has long-term value. As Sharma says, “We can use electricity because we understand electrons. We are already using protons to treat cancer...”
| “13 institutes from India are participating in various CERN projects”
About five years ago, CERN opened its membership to non-European countries. So far, Turkey is the only associate member. This May, India too began the process of becoming an associate member. Rüdiger Voss, head of international relations, talks about how this partnership would help both India and CERN. Excerpts
We are a European research organisation and began taking in associate members very recently. We perceive India as a natural candidate for partnership as we have had long standing tradition of scientific collaboration with the country. A total of 13 institutes from India are at present participating in various projects at CERN. We have 180 visiting researchers and scientists from India and this number is second highest in Asia, second only to Japan. India even contributed in the construction of our flagship project, the Large Hadron Collider (LHC), which is the world’s most powerful particle accelerator, and provided indigenous technologies and technical support. So far, it has been a successful partnership.
How will India benefit by becoming an associate member?
There would be three types of benefits. The first is political. As an associate member, India would be allowed to be part of governance of the organisation. It will still not have voting rights, but the contribution would be advisory and consultative. The second benefit is at a more practical level. As a member, scientists from India would be eligible to take full time positions at CERN. Students would be eligible for postdoctoral positions and fellowship programs. Indians would also be eligible for non-scientific, administrative jobs. The third and the biggest benefit would be for the industry which would be then eligible to do business with us. About 50 per cent of our budget is spent on procurement of goods and services. This would be very interesting prospective for the Indian industry. Our orders come in with built-in technology transfer, which helps the industry build new products and develop new knowhow. Companies can also use CERN’s name as a prestigious reference and develop markets in other countries. We have studied the economic impact of our procurements and we find for each Swiss franc we spend, the industry can make as much as three Swiss francs on the average.
How will CERN benefit?
By taking in associate members, we enlarge our constituency. Also, membership is not free and members have to contribute to the budget. Our budget is around one billon Swiss francs. We have a formula for calculating the contribution for European members. We use the same formula for associate members, but they have to give only 10 per cent of the calculated amount. India would have to give something like 10 million Swiss francs per year, but this money will be returned to India through positions and procurement. An associate member can give more for getting more benefits.
How long will it take for India to become a member?
This is difficult to forecast, it depends on Indian authorities now. We have sent back queries on the first set of applications sent by the department of atomic energy of India. Once the complete application is submitted, CERN council will assess and take a decision. We will then set up a taskforce that will travel to India to validate the form. We already know India’s capacity and this should be a relatively straightforward business. We will assess financial support to basic science. We will look at long-term sustainability as our experiments are long. For example, it took more than 25 years to design and to build the LHC. Sustainability should be longer than the career of a single researcher. The taskforce will also visit some industries to assess the growth potential. When the taskforce report is complete, it will go back to the council, which will then finalise the deal. Once this is cleared, the agreement would be signed between the country and CERN. The theoretical minimum for any country to become a member is one year. In practice we have not achieved it yet – it took Turkey longer than this. We have other applications in the pipeline and they too have been there for longer.
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