The accepted view today is that the Universe started with a gigantic explosion called the "Big Bang". For fractions of a second after the Big Bang, the Universe consisted of the most elementary constituents of matter interacting with each other through other particles which are carriers of different kinds of forces existing in nature. And, the carriers of all forces in Nature are "bosons", named after the famous Indian physicist Satyendra Nath Bose. The behaviour of these elementary particles is described today by a mathematical model called the Standard Model. According to Standard Model, all particles acquire mass through their interaction with another particle called the Higgs particle (also popularly called the "God Particle" in the Media), named after the British physicist Peter Higgs. The Higgs particle is again a boson. It is a matter of pride for us that bosons play such an important part in the evolution of Universe and, perhaps, also in the ultimate fate of the Universe.

Physical situations similar to what existed at fractions of a second after the Big Bang are experimentally created in laboratories through collision of particles or nuclei. That is the primary intellectual reason why high energy particle accelerators are built. The Standard Model has been tested with considerable precision in accelerator experiments so far and has come out with flying colours. The only missing link has been the Higgs Boson. Unfortunately, the Standard Model does not predict the mass of the Higgs Boson. As the Model continued to have excellent agreement with experimental observations, the anxiety to find the Higgs Boson also kept growing, especially because it plays such an important role in the structure of the Standard Model. All accelerators in the past continued with their search and put bounds on its possible mass.

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) was planned with the special aim of detecting the Higgs particle if its mass was below 1000 GeV. CERN, as a result of two experiments has recently reported discovery of a new particle, expected to be the long sought after Higgs particle.

The Large Hadron Collider at CERN

LHC is the most ambitious project undertaken by CERN so far. The LHC is a giant particle accelerator buried underneath the ground, 27 km in circumference and crossing throughSwitzerland and France several times. After the feasibility study and financial assurance from various countries in the world, the construction of LHC was launched in 1996. It is designed to produce proton-proton collisions with a centre of mass energy of 14 TeV, to be followed by collisions between lead nuclei involving a centre of mass energy of 1150 TeV. At the present time, it is producing proton-proton collisions at a centre of mass energy of 8 TeV. LHC, even at this lower operating energy at present, is already the highest energy particle accelerator ever built by mankind. Even a greater achievement has been the extremely large "luminosity" of collision that has been accomplished by the machine. This essentially means that protons can be made to interact at the interaction points with extremely large flux. The total cost of building the LHC has been about 4.5 Billion Euro and its annual operating budget is around 800 Million Euro. Further, the data volume at LHC is a big challenge for computing and this has been tackled via the development of LHC computing Grid, a new paradigm

Indian Contributions towards building up of LHC

The in-kind contributions that India committed to CERN involved hardware, software as well as skilled manpower support. The hardware supply opened a door for Indian industry to take up the challenge of delivering high-quality products for a cutting-edge international research project. RRCAT, Indore with a major programme in accelerators, was the nodal DAE institution which had the responsibility to carry out necessary R&D work to prototype and develop the components, so as to meet the given specifications before their large-scale production was entrusted to industry. The other institutions involve were BARC, VECC and IGCAR. India successfully supplied items like superconducting corrector magnets-sextupoles (MCS), decapoles (MCD) and octupoles (MCO); mechanical systems, namely precision magnet positioning system-jacks (PMPS-jacks); accelerator protection system-quench protection heater power supply (QPS), quench detection electronics (QDE) and control electronics for high current circuit breakers; vacuum system-vacuum system design for long beam transport lines for beam dumps; cryogenics-large capacity liquid nitrogen tanks and test facility for testing of Sc magnets at 4.2 K; engineering studies-analysis of cryogenic distribution line interconnects and test and analysis for magnets along with necessary technical documentation; and so on.

Indian Contribution to the CMS Experiment            

One of the leading experiments/detectors at CERN is the CMS (Compact Muon Solenoid) Experiment/Detector.  This is one of the two experiments at LHC which have led to the discovery of a new resonance, expected to be the much sought after Higgs Boson. This experiment will also probe into some other fundamental issues in physics, namely, physics beyond the Standard Model like supersymmetric particles; detailed properties of the top quark; search for new heavy gauge bosons; possible quark and lepton substructure, and so on.

5 Indian institutions have been are participating in this experiment: TIFR, BARC, DelhiUniversity, Panjab University, Chandigarh and Visva Bharati, Santiniketan (as an associate of TIFR group). Lately, SINP, Kolkata and IIT, Mumbai (as an associate of BARC group) have also joined this experiment. Participation of NISER, Bhubaneswar is under discussion. This research has been jointly funded by DAE and DST on 50:50 basis.

Towards hardware of the CMS Detector, the Indian groups have already contributed the Hadron Barrel Outer Calorimeter (HO-B) and the Silicon Strip based Pre-shower Detector (PSD) of the endcap electromagnetic calorimeter. In addition, the Indian groups have significantly contributed towards development of software, analyses strategy from early days of CMS and, finally, physics analyses of data. Frequent presentations of scientific results on behalf of CMS collaboration by Indian scientists in international conferences also indicate the significant role being played by the Indian scientific community in the overall functioning of CMS. The members of Indian collaboration have also been assigned CMS-wide coordination roles. At present, Indian scientists are also deeply involved in collection of data, monitoring and certification of data as well possible improvement in the performance of various detector subsystems.

Indian Contribution to the ALICE Experiment

Apart from accelerating protons, the Large Hadron Collider (LHC) will also accelerate and collide heavy ions, e.g. Pb ions with a centre of mass energy of 1150 TeV.

 The collision of such ultra-relativistic heavy ions is predicted to produce a new phase of strongly interacting matter at extremely high energy densities, called the Quark Gluon Plasma (QGP). This phase of matter is also believed to have existed in the very early Universe.  Search for QGP is an important goal at LHC. The ALICE (A Large Ion Collider Experiment) Experiment is the only dedicated experiment at LHC which will search for QGP.

Eight Indian institutions are participating in this experiment: VECC and SINP, Kolkata, IOP,Bhubaneswar, Panjab University, Chandigarh, Rajasthan University, Jaipur, Jammu University,Jammu, Aligarh Muslim University, Aligarh and IIT, Bombay. 4 new institutions – IIT-Indore, Bose Institute, Kolkata, Gauhati University and NISER, Bhubaneswar are expected to join this experiment very shortly. This research has also been jointly funded by DAE and DST on 50:50 basis.

 On the hardware side, the Indian groups have built a Photon Multiplicity Detector (PMD) and some Tracking Chambers for the Forward Muon Spectrometer. The Indian groups have also developed a special chip for the Forward Muon Spectrometer, called the MANAS chip.

In addition, the Indian groups have participated in development of software, experimental runs and, finally, in the physics analysis of data