LHC CMS and TIFR Kajari Mazumdar DHEP On

LHC, CMS and TIFR Kajari Mazumdar (DHEP) On behalf of TIFR-CMS Group NSF Meeting September 24, 2008

Eternal question of Mankind: What principles govern energy, matter, space and time at the most elementary level? Building blocks of matter We want to know the cosmic recipe. This is not the entire story! Present wisdom: Behaviour of matter particles can be explained in terms of very few fundamental interactions, which might have evolved over time as the universe cooled down from a single unified one.

• Quantum gravity era: t≈ 10 -43 s 1032 K (1019 Ge. V, 10 -34 m) • Grand Unifecation Era: t ≈ 10 -35 s 1027 K (1016 Ge. V, 10 -32 m) • t ≈ 10 -32 s: Strong forces freeze out Slight excess of matter over antimatter is generated. Existence of quark-gluon plasma. ENTER LHC • Electro. Weak era: t ≈ 10 -10 s, 1015 K (100 Ge. V, 10 -18 m) Electromagnetic and Weak forces separate. • Protons and neutrons form: t ≈ 10 -4 s, 1013 K (1 Ge. V, 10 -16 m) • Nuclei are formed t = 3 minutes, 109 K (0. 1 Me. V, 10 -12 m) • Today: t = 14 x 109 years, 3 K Energy =k. T, Length scale = hc/E

4 types of basic forces : Gravitational, Weak, Electromagnetic, Strong -40 -5 -2 Relative strengths: 10 : 1 neglect gravity And 2 types of particles : (i) fermions (matter particles like electron, quarks) (ii) bosons (carrier particles, like photon) SM encompasses 3 of the 4 interactions of elementary particles. Almost all the predictions of SM match very well, till date, with experimental observations (upto EW energy scale ~ 100 Ge. V). Some of the fundamental parameters are measured with amazimg 5. accuracy ~ 1 in 10 SM is still not a satisfactory Theory!

Presently Standard Model cannot explain the mass spectrum.

Symmetry Breaking and Higgs Mechanism Nature has various symmetries (translational, rotational, . . ) and related conservation laws: guiding principles in theoretical formulations. Some of the symmetries are also broken, sometimes spontaneously. Eg. behaviour of ferromagnet wrt temperature: above Curie point, the spin alignments are all random. Below critical temperature, the alignment direction is degenerate. Below C point Above C point In high energy physics assume all elementary particles to be massless to start with. As the universe cooled, particles acquired masses through breaking of symmetry.

• One of the corner stone of SM, the Higgs mechanism of EWSB is yet to be verified Higgs particle is not yet seen! EWSB endows masses to various fundamental particles. • Mass of the Higgs boson itself is not known from theory. Can be anything between 115 to 750 Ge. V as of today. Higgs particle has to be hunted out! experimentalists’ job. SM is NOT the complete description of physics at very high energies. e. g. , corrections to Higgs mass grows beyond control unless some New Physics, which is at work at Te. V energy scale, is postulated. Particles of interesting properties should 2 show up if enough energy is gathered to produce them. (E=mc )

Serious discussions started 23 years ago to build an exploratory, high energy, high intensity machine which can produce heavy particles of mass upto few Te. V (1 Te. V = 1012 electron. Volt = 1. 6 * 10 -7 Joule Lets’s Have the Collider: LHC! • Unravel the mystery of Electro. Weak Symmetry Breaking. • Probe the physics at Te. V energy scale. (Is Super. Symmetry or Extra Dimension relevant for EWSB? ). • Direct Search for production of dark matter candidate. • Study the asymmetry between matter and anti-matter. • Study of Quark-Gluon Plasma. • …………

Evidence of Dark Matter Rotation curve of galaxies (distance vs. velocity) Effect of dark matter LHC will be able to search for the candidate of Dark Matter. LHC will not provide insight into Dark Energy!

• Different particles and forces are just different oscillation modes -33 of tiny strings, of length ~ 10 cm. • Instead of usual 3 spatial dimensions, there may be additional ones, which are curled up too small to be observed! • Gravity may appear weak only because its force is being shared with (or leaks into) other spatial dimensions. High-energy experiments could prise open the inconspicuous dimensions just enough to allow particles to move between the normal 3 D world and other dimensions, manifesting itself in the sudden disappearance of a particle. Or, LHC may produce with very, very small probability, a completely harmless Micro Quantum Black Hole!

Black Hole production In large extra dimensions Schwarzchild radius of proton increases from 10 -33 to 10 -17 cm If the impact parameter of two colliding protons is smaller than this distance, they coalesce into a micro blackhole. It evaporates, via Hawking radiation, within 10 -25 s spewing out many particles isotropically in the

Distance between 2 bunches 7. 5 m

The probe wavelength should be smaller than the distance scale to be probed: << h/p = hc/E Need accelerators for higher energies. Electronic eyes! Technological progress pushes frontiers of basic science research. Already probed upto 10 -18 m (Energy ~ few hundred Ge. V) Presently, LHC provides energy upto few Te. V, Equivalent to the kinetic energy of a fly!

Where is LHC? 27 km circumference ~ 100 m underground. Tunnel crosses franco -swiss border 8 times.

1232 diploe magnets ~ 400 quadrupole magnets +Various other types of magnets 27 km at 1. 9 K (superfluid He) Vaccuum ~ 10 -13 Atm. SC coils: 12000 tonnes/7600 km

Most sophisticated and complex detectors with size of big buildings. CMS : Compact Muon Solenoid 107 electronic readout channels.

Higgs event in CMS

The GRID: the new information Super highway. LHC employs a novel computing system, a distributed computing and data storage infrastructure: Worldwide LHC Computing Grid (WLCG). • tens of thousands of standard PCs collaborate worldwide • much more processing capacity than a single supercomputer • access to data to thousands of scientists all over the world. Heirarchical structure with Tier-0 at CERN ~ 10 Tier-1 s, ~ 40 Tier-2 s (including TIFR & VECC/SINP)

CMS during September, 2008 Cosmic ray muon in CMS Beam halo in CMS

HO: INDIA

We did not miss the boat! Late P. K. Malhotra started discussing India’s participation during early 90 s. • LHC enthusiasts from CERN have been visiting TIFR from 1991. • TIFR joined CMS collaboration in 1993. • Several Indian groups in ALICE experiment. • LHC Accelerator activities: engineers from RRCAT, Indore from 1994/5 (fabrication of corrector magnet, precision jacks). Accelerator scientists from other DAE institutes joined in the assignment of testing magnets at CERN. • TIFR-CMS group for GRID project in 2002. • BARC computing division in GRID computing development.

TIFR group involved in R&D hardware, simulation activities from 1992. India-CMS collaboration at present: TIFR, Panjab U, Delhi U, BARC, and recently, Visva-Bharati U Hardware responsibilities: - Outer hadron calorimeter: TIFR, Panjab U. - Silicon Pre-shower Detector: BARC & Delhi U. Software: significant contribution in CMS detector specific simulation efforts. Computing: CMS-Tier 2 Grid computing facility. Physics contribution: from early stage on (~1994).

• Search for Trileptons in Chargino-Nutralino decays • Estimation of Bottom-content of Proton at LHC. • Study of Quark Compositeness at LHC • Search for Invisibly Decaying Higgs Particle. • Potential of Little Higgs Model at LHC • Measuremnet of bb. Z cross-section. • MSSM CP-Violating Higgs Study. • Search for Charged Higgs in decay mode.

• Study of W + events in CMS. • Search for rare decay process of Bs • Study of Z+jet (s) events in CMS. • Study of W-charge asymmetry in CMS. • Calibration of HO subdetector using cosmic muons • Intercalibration of HO detector units using Laser. Physics simulation studies are essential for detector design optimization in terms of • Study of detector response in Test Beams. physis potential , feasibility of final states, improvements in software techniques, designing of trigger strategy, optimization of analysis tools and so on. • With high luminosity and very complex detector, extraction of physics results at LHC is both exciting and demanding job.

Detailed R&D of detector design and quality controls(1996 -2001). Fabrication of detectors done mainly at TIFR(2002 -4). Housings assembled in Mumbai industry; Honeycomb panels from Bangalore. Active participation in test beam activities at CERN to understand detector response with high energy beams. By April 2004 all 432 trays & 72 housings for HO detectors had been sent to CERN. 2005 -07: installation and cabling carried out (testing of read-out boxes, cable routing, cable lengths, cable fabrication) at CERN. Continuous commissioning and calibrations carried out since 2006.

Installation of HO housings

HO detectors on surface Cherry-pickers to install detector components, cables.

Tier 2: India. CMS-TIFR • Small scale setup is already functioning well. • Presently, network bandwidth 1 Gbps Storage: currently 50 TB (raw) disk space, projected 400 TB. Computing: currently, 80 K SI 2 K equivalent Dual Xeon. Near future: 45 blade server (quad. core dual processor, cloverdown) eqv. 380 K SI 2 K Equivalence: Pentium 3 at 800 MHz~1, 200 SI 2 K World-wide GRID-Fest on October 3!

LHC is indeed a big deal to us! • LHC opens up a completely new, vast world, in terms of the physics possibilities. • Anticipation of The Discovery is tremendous. • Initial Years of LHC validation of the experiment. • Reaping the physics harvest at LHC is a challenge zillion times tougher than finding a needle in the haystack! • Several “first studies” have been made in the context of the experiment. Contributions are well recognized. LHC is a voyage into Terra Incognita: we may see completely unexpected physics! LHC will settle the issue of Higgs mechanism, SUSY, etc.

Late P. K. Malhotra, (Retd. ) S. N. Ganguli, V. S. Narasimhan, R. Raghavan, M Krishnaswamy. (Sunanda) Acharya, Aziz, Banerjee, Dugad, Guchait, Gurtu, Majumder, Mazumdar, Mondal, Sudhakar, students, … Chendvankar, Satya, Kalmani, Nagraj, Deshpande, Reddy, Mandakini, Verma, Chandrasekharan and many technicians in the labs. Special thanks to various supporting sections of TIFR for help at different stages.

• Today Particle Physics stands poised in Discovery Horizon. • September 10, 2008 marked the beginning with a single step for Journey of thousand miles. . Newton: To me there has never been a higher source of earthly honour or distinction that connected with advancement in science. STAY TUNED!

CMS Detector Silicon Tracker ~250 square metres of silicon detectors - 25 m-long swimming pool The silicon Pixel detector comprises (in its basic form) more than 23 million detector elements in an area of just over 0. 5 sq. m. 80, 000 lead tungstate crystals: 98% metal by mass, but completely transparent. Supported by 0. 4 mm thick carbon fibre and glass-fibre structures. The brass in endcap HCAL from recuperated artillery shells from Russian warships CMS Magnet, the largest solenoid on earth has field strength 100, 000 times stronger. Amount of iron used as the magnet return yoke ~ Eiffel Tower Data volume per second ~ 10, 000 Encyclopedia Britannica.

LHC Utilization -- ALICE HMPID TOF TRD TPC PMD ITS Muon Arm PHOS