La HADRON COLLIDER (LHC):SEARCH FOR ‘GOD PARTICLE’
At about 10.28 (local time) in the morning, on Wednesday, 10th September,2008, an exciting experiment took place at the CERN Laboratory, Geneva, Switzerland. It was a giant experiment, known as LHC – Large Hadron Collider – experiment, carried out on the world’s largest machine. It is the first of the series of experiments, which are going to take place in near future. The whole world was anxious to know the outcome of this experiment. The scientists are expecting so many things from this magnificent work. They will be trying to understand how the universe started, what happened shortly after the big bang and also expect to reveal more about the dark matter, dark energy, anti-matter, hidden dimensions of space-matter and the evidence of the hypothetical particles- the Higgs Bosons, to which some people, including some scientists – Nobel winning physicists Leon Lederman is one of them- refer to as the God Particles. The results of LHC experiments will probably change our fundamental knowledge of the universe. Really, very exciting expectations!
On the other hand, there is a hue and cry against this first and the follow up experiments. People have gone to the court of law to get an injunction to this experiment. There are cases pending against it in the Honolulu Federal court of the state of Hawaii, US and in the European Court of Human Rights, Strasbourg, France, pleading that the experiment is going to create black holes on earth, which would grow exponentially and would swallow the whole earth, ending the life on the earth. The human life is at risk, they say. Is it not a very bad situation for every one of us, if the fears of some people come out to be true?
What is this mysterious gigantic experiment? What is this CERN laboratory? what is LHC? What is the cost of this experiment? What is Big Bang and what are these God Particles? Why the people have challenged this experiment in the court of law? In what way,as some fear, it is going to swallow the earth and eliminate the life on this planet. Is it really true that every one of us is going to die if this experiment comes out to be successful? …….these and other several questions, which a layman may ask after reading the news about this experiment. Let us try to address some of them.
What is this CERN?
CERN is a short form of a French name of the research laboratory, the English translation of which is EUROPEAN ORGANIZATON FOR NUCLEAR RESEARCH. Even though this English name is internationally accepted, the original French short form- CERN- is still in use for this research organization. This research organization is situated in Geneva, Switzerland, near the Swiss-French border. It is one of the world’s largest and most respected centers for scientific research. Its business is fundamental physics. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter —— the fundamental particles and the forces acting between them. By studying what happens when these particles collide, physicists try to learn about the Laws of Nature. From these findings, they are trying to find out what the Universe is made of and how it works.
At the time, when this institution was founded, pure physics research was concentrated on understanding the inside structure of atom, hence the word ‘nuclear’. Today, our understanding of matter goes much deeper than the nucleus, and therefore the main area of research here now is particle physics — the study of fundamental constituents of matter and the forces acting between them. But the word ‘nuclear’ is still retained. CERN is run by 20 European Member States which have special duties and privileges. They make contribution to the capital and operating costs of CERN’s programs and responsible for all important decisions about the Organization and its activities. Some states, for which membership is not possible, are given Observer Status. India and USA, along with other five states, have this Status. There are other 36 states, which are not the members of any kind, are also involved in the CERN programs. Some 8000 visiting scientists, half of the world’s particle physicists, come to CERN for their research .They represent 580 universities and research institutions and 85 nationalities. It is a global endeavor
There is a statue of dancing Lord Shiva at CERN near the building A40, given by the Department of Atomic Energy, India, as a gift, celebrating CERN’s long association with India, which started in the 1960’s and continues strongly today. The statue was unveiled on June 18, 2004.
The dance of Shiva is symbolic of the dynamic forces of creation and destruction, and the harmonious balance of opposites. Dance of Shiva is also supposed to be the position of Cosmic forces after splitting.
[ During the first half of the 20th century, achievements in Europe dominated in physics, from the discovery of the electron to the atomic nucleus and its constituents, from special relativity to quantum mechanics. Sadly, the conflicts of the 1930s and 40s (Second World War) interrupted this, as many scientists had to leave for calmer shores. The return of peace heralded some decisive changes. By the early 50s, the Americans had understood that further progress needed more sophisticated instruments, and that investment in basic science could drive economic and technological development. While scientists in Europe still relied on simple equipments based on radioactivity and cosmic rays, powerful accelerators were being built in the US. Table-top experiments were being overtaken by projects involving large teams of scientists and engineers.
A few far-sighted physicists, such as Rabi, Amaldi, Auger and de Rougemont, perceived that co-operation was the only way forward for front-line research in Europe. Despite fine intellectual traditions and prestigious universities, no European country could cope alone .The creation of a European Laboratory was recommended at a UNESCO meeting in Florence in 1950, and less than three years later, a Convention was signed by 12 countries,and the European Council for Nuclear Research, a provisional body was founded in 1952 with the mandate of establishing a world-class fundamental physics research organization in Europe. When the organization officially came in being in 1954, the Council was dissolved, and the new organization was given the title- European Organization for Nuclear Research, although the name CERN was retained.]
CERN has, to its credit, the following achievements –
1. Nobel Prize to Carlo Rubbia and Simon Van der Meer in physics ( 1984 ) for their discovery of W and Z field particles which are responsible for Weak Interactions, one of the four basic interactions. Their experiments at CERN confirmed the unification of weak and electromagnetic interactions (forces ) , the electroweak theory of the Standard Model. [ We can recall that in 1979, Nobel was awarded to Glashow, Abdus Salam and Steven Weinberg, who established the unification of weak and electromagnetic interactions into one- electroweak interaction and proposed the existence of W and Z field particles ,the actual experimental discovery of which was confirmed at CERN in 1983-4 ]
2. Nobel Prize to George Charpak in physics (1992 ) for the development of a particle detector used for exploring the innermost parts of matter.
3. WWW, the World Wide Web was first proposed at CERN in 1989 and further refined in 1990.
4. The Large Hadron Collider (LHC) – Along with other achievements, CERN has come into limelight on 10th September, 2008, when the LHC was declared operational.
The LHC is a circular particle accelerator. It is, therefore appropriate here to know something about particle accelerator.
Particle Accelerator (atom smasher) is an instrument which uses electric field to increase the speed of particles when they passed through it. In the beginning, particles were accelerated in a tube by subjecting it to a high voltage, applied over a gap between a cathode and an anode (the electrodes). This tube is a simple form of an accelerator. It is called as cathode ray tube (CRT) and was conceived at the end of the 19th century.
The cathode ray tube (CRT) is a vacuum tube containing an electron gun,(a source of electrons) and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, and then smashes them into phosphor molecules on the screen .The collisions result in a lighted spot or pixel, on your TV or computer monitor to form images in the form of light emitted from the fluorescent screen. The image may represent electrical waveforms (oscilloscope), pictures (television, computer monitor ), radar targets and others. .
A particle accelerator works in the same way, except that they are much bigger in which the particles move much faster (near the speed of light) and the collision results in more subatomic particles and various types of nuclear radiations...It is remarkable to note that the simple accelerators are used in the discovery of the first subatomic particle, electrons. The further developments in understanding the inner structure of the atom is done with the help of higher form of accelerators .The developments we see in the field of electronics is because of the accelerators only. The Accelerators are also most commonly used for external beam radiation treatments for patients with cancer. It can also be used in radio surgery similar to that achieved using the gamma knife on targets within the brain. It delivers a uniform dose of high energy x-ray to the region of patient’s tumer.
In advanced form of particle accelerators, the speed of the particles is continuously increased by using electric fields and magnets. As the speed of the particle increases, the energy of the particle also increases. The speed of the particle can be increased to such a high level that it nearly reaches the speed of light but not equal to that of light, the limit which is imposed by Einstein’s theory. When particles with such a high speed and with such a high energy collide with each other, they are broken down ( smashed) in to fragments. The study of these fragments gives a wealth of information to the scientists which they can analyze and use for their research.
Accelerators are of two types : a) Linear and (b) Circular
(a) Linear accelerator (linac) is the simplest type of accelerator. Fundamentally, it is a long tube through which charged particles are passed and accelerated. In linac, a great many electrodes are separated by a small gaps. Stanford University has the largest linear accelerator ( 50 GeV), named as Stanford Linear Accelerator Center (SLAC). It is about 3 Km in length. The research at SLAC has produced three Nobels in Physics for the discoveries of for charm quarks(1976), quark structure inside proton and neutron(1990), the tau lepton(1995).
At the international level, it is planned to build a huge International Linear Accelerator (ILC), which
would have an initial capacity of 500GeV (see below * ), which could be steadily increased to 1000GeV
( 1TeV). Its length is expected to be between 30 to 40 Km. It was to be built at the Fermi Lab ,Illinois ,US.
where the cyclotron,, Tevatron is situated, but because of the inability of the US govt. to provide
necessary funding to build it in the US, the location of the proposed accelerator is not fixed, even though its
design is finalized in Feb.2007 And hence the execution of this project is pending.
[* Energy of a particle is measured in terms of an unit – electron volt. It is the smallest unit of energy and
defined ‘as the amount of kinetic energy gained by a single unbound electron when it accelerates through an
electrostatic potential difference of one volt’ , which has the value as: 1eV = 1.6 -19 J. The masses of
elementary particles are frequently expressed in term of electron- volts by making use of Einstein's
famous equation,
