` Usha Mallik's Research










The Mystery of Creation of our universe
The "Big Bang" produced our universe, and very shortly after particles and anti-particles were created in equal amounts according to the "Standard Model" (SM) of Particle Physics. While the SM agrees very well with all experimental data, it leaves a lot of questions unanswered. Only ~4% of the energy of the universe is visible matter (galaxies, stars, and all observed matter), which we know about; ~73% of the energy we do not know anything about, that is accelerating the expansion of the universe, we call this "Dark Energy". And there is also a lot of matter present that we know of from astrophysics and cosmological facts, but have not observed, quite fittingly this is known as "Dark Matter" and amounts to ~23% of the energy. Additionally, there are other mysteries. we live in a matter-dominated universe, even though SM says matter and anti-matter were created equally just after Big Bang. What made "Gravitational Interaction" so weak compared to the rest of the fundamental interactions? Why are there three generations of leptons and quarks and why are their masses so varied? Clearly, there is knowledge much more fundamental than the SM that remains to be acquired, of which SM is likely a small part. What is the scale of this? We keep searching for hints of physics beyond SM (BSM) in all areas, especially now at the Large Hadron Collider (LHC) at CERN currently operating at 13 TeV center-of-mass energy with colliding proton beams. We are involved in the ATLAS experiment, one of the two general purpose experiments constructed to collect and analyse data with plans for upgrades in stages, Phase 1 and Phase 2.
LHC, ATLAS and Upgrade R&D

Professor Mallik and her group joined the ATLAS experiment with SLAC at the end of 2006. She and her group are involved in the Silicon Pixel detector, with Alex Schreiner resident at CERN and fully involved in the DSP part of the project. Apart from initial physics calibration of the detector with the early data, the group is interested in Higgs and SUSY analyses.


The BaBar detector at SLAC was operational in 1999 and collected 500 fb-1 data until 2008. The detector is used to investigate the composition of matter using the B/B-bar system of mesons produced at the PEP-II collider at SLAC. It produced approximately xxx publications, mostly in Phys.ReV.Lett and others in Phys.Rev, produced xxxx Ph.D.s and many excellent scientists.
Activities in BaBar
  • Resposible for online trigger software system
  • Central role in BaBar DAQ
  • Level 3 trigger
  • Level 1 trigger software
  • Level 1 Trigger upgrade
  • Trigger commissioner
  • Trigger coordinator
  • Run coordinator
  • Construction of barrel electromagnetic calorimeter-mini crates and fanout boards
  • Calibration of electromagnetic calorimeter, CARE chips
  • Charmed Baryon Analysis Work leading to several "First Observations"
  • Charm analysis working group coordinator

Professor Mallik and her group are also involved in the research and development of the Linear Collider, the next international highest priority construction project in Particle Physics. It will be central in understanding the Higgs mechanism (by which fundamental particles acquire masses), as a complimentary study of that at the Large Hadron Collider (LHC). Her group is very invloved in establishing a Particle Flow Algorithm for the ILC detectors.

Past Research

Zeus is one of the two experiments at HERA, the only high energy electron/proton collider opearating in DESY, located in Hamburg, Germany. The project started in 1992 using Deep Inelastic scattering to probe the inner quark structure of the proton. Professor Mallik and her group worked on the U-Sc calorimeter online software and readout-electronics calibration. The group studied the rise of the gluon momentum density at low-x from the rise of elastic and inelastic charmonium production, calculated with perturbative QCD.

back to top