Special Physics Colloquium: The quantum beginning of the Universe
Throughout the cosmic evolution, minute primordial perturbations were amplified by the gravitational attraction and gave rise to all the structure we observe: galaxies, stars, planets and life itself. It is believed that the initial perturbations are of quantum mechanical origin and generated during an initial stage of accelerated expansion called inflation. I will discuss the theoretical and experimental status of this profound (and somewhat disturbing) idea.
Date and Time: Monday | October 21, 2024 | 04:00 PM
Venue: LHC
Speaker: Paolo Creminelli (ICTP- Trieste)
Galaxy-based gravitational wave observatory in your backyard and its promises
Very recent independent and coordinated investigations by the established Pulsar Timing Array collaborations strongly indicate that the universe is humming with gravitational radiation-a very low-frequency rumble that rhythmically stretches and compresses spacetime and the matter embedded in it. For these International Pulsar Timing Array-endorsed 3P+ efforts, the European and Indian Pulsar Timing Array consortia, namely EPTA and InPTA, pooled together their resources that included combining EPTA's second data release and InPTA's first data release. These efforts allowed us to probe and characterize the contributions of instrumental noise and interstellar propagation effects that are present in the various combinations of our pulsar data sets. The resulting detailed investigations reveal strong evidence for the presence of a stochastic gravitational wave background. I will share the excitement of our InPTA collaboration which is an Indo-Japanese effort that employs niche abilities of India's upgraded Giant Metrewave Radio Telescope (uGMRT). Possible future directions that should be exciting to both astronomers and physicists will be listed.
Date and Time: Wednesday | March 13, 2024 | 04:00 PM
Venue: Seminar Room 31
Speaker: Achamveedu Gopakumar (TIFR, Mumbai)
Dynamic Radius Jet Clustering Algorithm
The emergence of jets, bunches of collimated hadrons, in high-energy colliders is a prevalent phenomenon. In the current LHC context, along with traditional narrow QCD jets, the study of fat jets, which may appear as a result of the decay of a heavy particle, has become an essential part of collider studies. Current jet clustering algorithms, namely $k_t$-type sequential recombination algorithms, use fixed radius parameters for the formation of jets from the hadrons of an event in a collider. The appearance of differently-sized jets in a single event from such algorithms is, therefore, impossible to achieve. In our work, we made an attempt to form differently-sized jets via the dynamic radius chosen during the evolution of each jet. Instead of keeping the constant radius parameter of the standard $\kt$-type sequential recombination algorithms, we allowed the radius to vary dynamically based on the local kinematics and distribution in the $\eta$-$\phi$ plane around each evolving jet. In this talk, I will discuss our methodology of the dynamic radius jet algorithm. I will then present the usefulness of the algorithm at the 13~TeV LHC through some example processes from SM and BSM scenarios.
Reference: https://inspirehep.net/literature/2627836
Date and Time: Wednesday | February 21, 2024 | 02:00 PM
Venue: Seminar Room 31
Speaker: Tousik Samui (IISER Kolkata)
Dynamical Formation of Merging Binary Black Holes and the Way Forward
The discovery of merging binary black holes via the gravitational waves they radiate has kickstarted one of the most exciting time to understand how high-mass single and binary stars evolve, form black holes (and other compact objects), and end up in configurations that would merge within the Hubble time to be detectable by the LIGO-Virgo-Kagra detectors. I will review the different formation channels for merging binary black holes. I will focus on the formation of these systems through various dynamical processes and present key results. Finally, I will discuss some of the current outstanding questions and possible avenues to improve our ability to answer them.
Date and Time: Thursday| February 16, 2024 | 04:00 PM
Venue: Seminar Room 31
Speaker: Sourav Chatterjee (TIFR, Mumbai)
Compact stars as probes of nuclear and particle physics in light of multi-messenger astronomy
Date and Time: Wednesday| January 17, 2024 | 04:00 PM
Venue: Seminar Room 31
Speaker: Debarati Chatterjee (IUCAA, Pune)
High Accuracy waveform models for high precision gravitational wave astronomy
Date and Time: Wednesday| August 16, 2023 | 04:00 PM
Venue: Seminar Room 31
Speaker: Tousif Islam (KITP, Santa Barbara)
Compact Stars as Calorimeters of Dark Matter
Date and Time: Wednesday| October 25, 2023 | 04:00 PM
Venue: Seminar Room 31
Speaker: Nirmal Raj (IISc., Bangalore)
Gravitational Waves from NNaturalness
Date and Time: Friday| November 10, 2023 | 04:00 PM
Venue: Seminar Room 31
Speaker: Akshay Ghalsasi (University of Pittsburgh, U.S.A )
Select puzzles in flavor physics
Date and Time: Monday| December 4, 2023 | 04:00 PM
Venue: Seminar Room 31
Speaker: Dr Bhubanjyoti Bhattacharya, (Lawrence Technological University, U.S.A)