The Ministry of Science & Technology of the Indian government has through a release (29th August) informed about the country's contributions to research related to the Large Hadron Collider. This will be useful information to students following Indian developents in science.
The
accepted theory for the origin of Universe is the theory of "Big
Bang". The the Universe started
with a gigantic explosion called 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 Department of Atomic Energy
(DAE) and the Department of Science and Technology (DST) of the Government of
India are organizing a one-day National Meet on "India at the Large Hadron
Collider (LHC)" at the Indian National Science Academy (INSA), New Delhi
with assistance from INSA and Vigyan Prasar, Noida. The purpose of the Meet is to showcase
Indian contributions to the construction of LHC, the CMS (Compact Muon
Solenoid) and ALICE (A Large Ion Collider Experiment) Experiments and the
development of the LHC Computing Grid.
The
Large Hadron Collider (LHC) 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 through Switzerland 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. The physics studies are carried out at LHC at 6 ‘collision points’, 4 of which are equipped with large detector set-ups.
These are CMS, ALICE, ATLAS and LHCb
and will provide the scientists a peek into a totally unexplored micro-cosmic
world. Scientists from Indiahave taken part in building the LHC machine and the
first two of these four detector set-ups. 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.
LHC
as an example of Mega Science
Facilities such as the LHC, by virtue of their resource requirements, technical complexity of building, and the gigantic efforts required in carrying out and analyzing the data produced by the experiments, fall into the class of research facilities which are commonly called now as "Mega Science Facilities".
The outstanding questions in Particle Physics today are at a length scale which require particle probes at extremely high energies. The physics questions that it tends to answer belong to the sub-nuclear length scales or to very early stages in the evolution of the Universe (picoseconds to microseconds after the Big Bang).
Such high energy probes are produced at particle accelerators like the LHC which are multi-billion dollar facilities. These are no more affordable for individual nations and, hence, international consortia engage in building and managing such facilities. Technologically, such facilities are engineering marvels pushing the technology frontiers to their extreme in wide range of engineering disciplines.
All of this requires that the best in the world pool not only their financial resources but also their intellectual resources to build such facilities. The coordination among scores of research laboratories spread all over the globe and participating in such efforts is remarkable.
Such facilities have a long list of very useful technological spin-offs – the World Wide Web being one of them. WWW was invented at CERN in connection with previous generation experiments at the Large Electron Positron (LEP) collider facility.
The need, challenges and benefits of engaging in such "Mega Science" pursuits will be discussed during the Meet.
History
of CERN-India Collaboration – The Run-up to LHC
The history of
Collaboration between CERN and India is a long one. It started with
scientist-to-scientist and institutional collaborations in the 1960's.
Scientists from TIFR won recognition for their contribution to the L3 detector
in the 80's.
The collaborations gradually built up with time. In order to further increase the pace of accelerator development in our country and to give a thrust to experimental high energy physics programme, DAE and CERN signed an agreement of cooperation in 1991 for a ten year period. In the early years of this agreement, the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore successfully delivered a few sub-systems for upgradation of LEP-200 project, thereby confirming viability of such an arrangement.
The formal framework provided by this agreement was also tapped by the Indian High Energy Physics (HEP) community by participating in a frontier area of research involving the heavy (lead) ion collision programme being carried out at CERN. A number of DAE institutions and universities (supported by DST) took part in these efforts and won recognition for their scientific efforts.
So, when CERN launched its most expensive LHC project, and was looking for competent partners in this programme, in terms of ideas, hardware and manpower, our past association came in handy. A protocol was signed in March 1996 between DAE and CERN and India joined the LHC project and agreed to provide in-kind contribution in terms of hardware, skilled manpower and software to the tune of 25 million USD (equivalent to 34.4 million Swiss francs).
By 2001-02, different components identified for Indian contributions to LHC had touched 34 million Swiss francs and large-scale fabrication of many such components was well on course, with the help of large industrial enterprises in the country.
This convincingly established our credentials and ultimately resulted in (i) CERN extending the 1991 cooperation agreement with India for a further ten-year period; (ii) our in-kind contribution on the request of CERN being enhanced to 60.4 millions Swiss francs; and (iii) India being accorded the ‘Observer status by CERN Governing Council with only Israel, Japan, the Russian Federation, Turkey, USA, EC and UNESCO being the other observers. The CERN-India Collaboration has reached a new height recently with India becoming an Associate Member.
Indian
Contributions towards building up of LHC
The in-kind contributions
that Indiacommitted 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.
Five
Indian institutions have been are participating in this experiment: TIFR, BARC,
Delhi University, PanjabUniversity, 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, Bhubaneswaris 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.
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.
Indian Contributions to the Worldwide LHC Computing Grid (WLCG)
Through
judicious choice the data archival rate is reduced by many orders of magnitude
and finally about few Giga bytes of data is stored for subsequent analyses in
detail. In the heavy operation, each collision is expected to generate up to
2000 subsidiary particles, which is observed through 180,000 channels. The
total data generation amounts to about 8-10 Petabytes (1000, 000 Gigabytes) in
a year of experiment time.
CERN has used very effectively the technology of Grid Computing to carry out physics analysis with this voluminous amount of data. This has been possible due to the availability of high speed networking over large distance. The basic principle is to store, manage, monitor and make available data to a collaborating scientist at anytime, anywhere in the world. Effective use of this technology is partly responsible for quick results from the experimental runs so far.
The WLCG is a tiered structure of distributed computing resources used by all scientists working at the LHC. India hosts 2 Tier-2 Centres at TIFR and VECC and a large number of Tier-3 Centres at various institutions.
Indian scientists at BARC have developed and deployed a number of software projects successfully in collaboration with IT Division, CERN. They have developed important software tools like GRIDVIEW and SHIVA. Gridview is a tool that is used by the WLCG/EGEE communities to visualize various functional metrics of the grid.
The members of the Gridview team in Computer Division are seen as experts in availability and reliability and are acknowledged for their experience in developing and running the very large Terabyte scale databases used by Gridview. SHIVA is a software tool for implementing problem tracking systems for software projects. In addition, all groups in the CMS and ALICE Experiments have utilized the WLCG for simulations and for analyzing the physics data.
This research has also been jointly funded by DAE and DST on 50:50 basis. The investments in LHC-related activities since 1996 (i.e. over 15 year period) will be approximately Rs. 400 crore.
Impact
of India's engagements at LHC
The number of experimental
groups in experimental high energy physics have steadily grown because of our
LHC involvement. Several students who completed their doctorates on LHC related
projects have joined leading institutions after valuable post-doctoral
experience abroad. At the national level also, our engagement with LHC has led
to increased collaboration among institutions in the country. It has also led
to exemplary coordination and cooperation between DAE and DST.
Finally, as a result of our efforts and investments, India proudly shares the results coming out of LHC which are at the very frontiers of human knowledge. There is today in the country a vibrant 150-200 strong community of scientists and research students in the area of experimental high energy physics.
And, most importantly, a large number of young scientists are in the making at any give time due to their participation in these intellectually challenging and exciting scientific ventures.
Finally, as a result of our efforts and investments, India proudly shares the results coming out of LHC which are at the very frontiers of human knowledge. There is today in the country a vibrant 150-200 strong community of scientists and research students in the area of experimental high energy physics.
And, most importantly, a large number of young scientists are in the making at any give time due to their participation in these intellectually challenging and exciting scientific ventures.
