CHEP

Monsoon Meet on Gauge Gravity
2025-08-22 - 2025-08-24
The Monsoon Meeting on Gauge Theories and Gravity is a 3-day conference bringing together leading researchers from across India working on various aspects of gauge theory and gravity. The event aims to highlight recent advances and foster research synergies within the Indian theoretical physics community. Designed as an intimate and focused gathering, Monsoon Meeting will feature in-depth talks and discussions on topics such as quantum gravity, black hole physics and cosmology. With participants spanning multiple institutions and areas of expertise, the meeting provides a platform for both established and emerging voices in the field.
Set against the backdrop of the monsoon season, the meeting offers not only rigorous scientific exchange but also a chance to step back, reflect, and spark collaborations in an immersive and intellectually stimulating setting.. Beyond formal presentations, ample time is reserved for informal discussions, collaboration-building, and open-ended exploration of new directions in fundamental physics.
List of Speakers

Sandipan Sengupta (IIT Kharagpur)
Sumati Surya (RRI)
Alok Laddha (CMI)
Suneeta Varadrajan (IISER Pune)
Ayan Chateerjee (Central Univ of Himachal)
Nilay Kundu (IIT Kanpur)
Krishna Mohan Parattu (IIT Mandi)
Nirmalendu Acharya (IIT Bhubaneshwar)
Sudipta Sarkar (IIT Gandhinagar)
Avirup Ghosh (Kulti College, West Bengal)

Organizers:

Gaurav Narain, CHEP
Sachindeo Vaidya, CHEP
Nirmalya Kajuri (IIT Mandi)
Sanved Kolekar (IIA)
Kartik Prabhu (RRI)

Pre-Registration :
Candidates will be selected based on the responses to the form. Selected candidates will be contacted via email by the organizers.
Selected candidates must confirm their participation, by completing the registration form, sent to them and by paying the corresponding registration fee.
Form : https://forms.office.com/r/wH1VgdW7d9
Registration Fee :

INR 5000 + GST : For all Faculty
INR 4000 + GST: For all Participant requiring on campus accommodation
INR 2000 + GST : For all participant not requiring accommodation

18 % GST is applicable on the registration fee
For more details visit the INDICO Page.

HSF-India Scientific Computing Workshop
2025-06-15 - 2025-06-21
We at the Centre for High Energy Physics (CHEP) are organizing a Scientific Computing workshop with the HSF-India research software collaboration.
This workshop covers

Scientific Python
Parallel programming and hardware accelerators
Basics of Machine Learning
Real-time triggering software (includes FPGA)

The workshop includes a valuable hands-on component, facilitated by leading researchers from Princeton University, Stanford University, and Fermi National Accelerator Laboratory.
This workshop will be held from 15 to 21 June 2025. The first two days of the workshop will be an introduction to high-energy physics data analysis and programming methods, which are open to all disciplines who are interested in joining the software collaboration movement independently of the discipline. The following five days will be a more in depth workshop on research software topics primarily of interest to those working (or planning to work) on experimental aspects of high-energy physics, nuclear physics, particle astrophysics and data science pursuits.
This workshop primarily targets master’s and early-stage PhD level students. However, anyone is welcome to attend.
Registration will be open on 2nd May 2025.
For Registration and more details visit the Official INDICO page

Seminar - Dr. Pallabi Das
2025-06-13 14:30 - 15:30 UTC
Title: New physics searches at the CMS experiment with novel trigger algorithms and analysis techniques
Speaker: Dr. Pallabi Das, RICE University U.S.A.
Time: 2:30pm
Venue: LH-3
Abstract:
The trigger system of the CMS experiment at CERN has been evolving continuously since the startup of the LHC. New features and algorithms have been developed during Run-3 to take care of higher data loads due to increasing instantaneous luminosity and pileup, and to include new experimental signatures. Beyond Run-3, the trigger system will undergo a major upgrade to replace hardware and require complete remodelling of the trigger algorithms. We will discuss a few of these algorithms, which have been tested and implemented in hardware. In addition, ongoing efforts to include unexplored phase space to search beyond the standard model signatures will be presented.

Colloquium - Dr. Pallabi Das
2025-06-12 16:00 - 17:00
Title: Hunting for Beyond the Standard Model Higgs at the CMS experiment
Speaker: Dr. Pallabi Das, RICE University, U.S.A.
Time : 4:00 PM
Venue: Auditorium
Abstract:
The Higgs boson was discovered by the LHC experiments in 2012. Several theories beyond the standard model predict this particle to be a portal to new physics interactions. Recent measurements hint that the Higgs boson branching fraction to undetected particles could be as high as 16%. It is thus important to search for possible rare and exotic decay modes directly. In this talk, we will discuss exotic Higgs boson decays into a pair of pseudoscalar particles (a) interpreted in the Two-Higgs-Doublet Model extended with a complex scalar singlet (2HDM+S) using data from the CMS experiment at LHC’s Run-2. The findings in the H→ aa → ττbb final state analysis will be presented. We will also briefly discuss how the CMS experiment plans to improve searches and measurements for Run-3 and HL-LHC.

Seminar - Dr. Anindya Ghosh
2025-06-12 14:30 - 15:30
Title: New Physics with ATLAS: Dark Matter, Di-Higgs, and the HL-LHC Future
Speaker : Dr. Anindya Ghosh, University of Arizona, U.S.A.
Time: 2:30pm
Venue: LH-3
Abstract:
Uncovering the particle nature of dark matter and exploring physics Beyond Standard Model (BSM) remain central goals of the LHC physics program. Collider searches provide sensitivity to a broad class of BSM scenarios, particularly those predicting final states with large missing transverse momentum and Higgs bosons. At the same time, the measured properties of the 125 GeV Higgs boson leave unresolved questions about the structure of the scalar sector and the stability of the electroweak scale. Di-Higgs production, especially via heavy resonances, offers a powerful probe of models such as two-Higgs-doublet extensions and Higgs-portal dark matter frameworks, motivating searches in high-pT regimes.
This talk presents recent ATLAS results targeting dark matter and BSM resonances decaying to Higgs boson pairs, focusing on the bbWW final state in boosted topologies. These analyses employ advanced jet reconstruction techniques and machine learning-based classifiers to enhance sensitivity in high-occupancy environments, setting important new constraints on theoretical models. Looking ahead to the High-Luminosity LHC (HL-LHC), ATLAS is undergoing significant upgrades, including a new all-silicon Inner Tracker and a completely redesigned trigger system. A key element is the introduction of Event Filter tracking, providing quality tracking to enable complex event selections. In parallel, a unified machine learning tagger is being developed to identify boosted Higgs, W-boson, and top candidates. These developments are essential to sustain and extend the experiment’s reach for rare BSM signatures in the HL-LHC era.

Colloquium - Dr. Anindya Ghosh
2025-06-11 16:00 - 17:00
Title: Signals in the Shadows: Dark Matter and BSM di-Higgs in ATLAS
Speaker : Dr. Anindya Ghosh, University of Arizona, U.S.A.
Time: 4:00pm
Venue : Auditorium
Abstract:
Unveiling the nature of dark matter and exploring physics Beyond Standard Model (BSM) are among the most profound questions in modern science. Despite compelling astrophysical evidence, dark matter’s fundamental nature remains a mystery, driving dedicated searches at the Large Hadron Collider (LHC). Concurrently, the discovery of the Higgs boson has opened new avenues to probe the fundamental forces and particles, yet it also points to unresolved puzzles regarding the stability of the electroweak scale and the possibility of a richer, undiscovered scalar sector. Di-Higgs production offers a unique window into these extended Higgs sectors, potentially revealing connections to dark matter and other new phenomena. This colloquium will present the latest progress from the ATLAS experiment in the search for dark matter and BSM resonances that decay into Higgs bosons. We’ll explore how ATLAS is pushing the boundaries of discovery, even in the most challenging event environments. Looking ahead, the talk will outline the ambitious High-Luminosity LHC (HL-LHC) upgrade program for the ATLAS detector, including transformative enhancements to its inner tracking and trigger systems. We’ll also highlight the critical and expanding role of machine learning, which is revolutionizing how we reconstruct particles and classify events, dramatically increasing our sensitivity to elusive new signatures. Together, these advancements position ATLAS to lead the charge in answering some of humanity’s deepest questions about the universe in the coming decade.

Seminar - Dr. Srijit Paul
2025-06-10 14:30 - 15:30
Title : Probing the QCD spectrum and its implications from first principles
Speaker : Dr. Srijit Paul
Maryland University, USA
Date : 10th June 2025
Time : 2:30 PM
Venue : Lecture Hall 3, Physical Science building
Abstract:-
Quantum Chromodynamics (QCD), the fundamental theory governing quark–gluon interactions, becomes especially challenging at low energies, where confinement and light quark masses preclude perturbative methods. Lattice QCD offers a powerful, first-principles non-perturbative approach to probe the low-lying QCD spectrum, including unstable resonances such as the ρ(770)meson and the ∆(1232)baryon. In this talk, we present one of the first results for the lattice determination of the ρ(770) resonance parameters at physical quark masses that also agree with the experimental values. We demonstrate the importance of smearing and multi hadron operators in extracting the finite volume spectrum and the resonance parameters. Precisely determined spectra improve predictions of long-distance phenomena and reduce uncertainties in observables such as the anomalous magnetic moment of the muon and CKM matrix elements. By refining our understanding of multi hadron states, we can improve the precision of predictions and better guide experimental efforts aimed at testing the Standard Model.

SEMINAR - Dr. Sridip Pal
2025-05-08 14:00 - 15:30
Speaker : Dr. Sridip Pal
CALTECH, USA
Title : Hyperbolic Manifolds and Conformal Bootstrap
Date : 8th May 2025
Time : 2:00 PM
Venue : LH-3, New Physical Science Building
Abstract:-
We point out that the spectral geometry of hyperbolic orbifolds provides a remarkably precise model of conformal field theory. Given a d-dimensional hyperbolic orbifold, one can construct a Hilbert space of local operators, living in an emergent (d-1) dimension and transforming as a unitary representation of the Euclidean conformal group in (d-1) dimensions. The scaling dimensions of these operators are related to the Laplacian eigenvalues on the orbifold. One can further introduce a notion of operator product expansion (OPE) and correlation functions among these operators. The associativity of OPE leads to bootstrap/crossing equations, which can then be used to put rigorous bounds on Laplacian eigenvalues on the orbifold. Specifically, we use conformal bootstrap techniques to derive rigorous computer-assisted upper bounds on the lowest positive eigenvalue $lambda_1(X)$ of the Laplace-Beltrami operator on closed hyperbolic surfaces and 2-orbifolds $X$. In several notable cases, our bounds are nearly saturated by known surfaces and orbifolds. For instance, our bound on all genus-2 surfaces $X$ is $lambda_1(X)leq 3.8388976481$, while the Bolza surface has $lambda_1(X)approx 3.838887258$. We use the bounds to identify the set of first nontrivial eigenvalues attained in hyperbolic orbifolds. Including spinors in the game, we produce exclusion plots on the plane of the first nontrivial eigenvalue of the Laplacian and the first nontrivial eigenvalue of the Dirac operator on a spin orbifold. We identify the orbifolds living on the kink appearing in these exclusion plots. If time permits, I will discuss how a notion of “Euclidean positivity” emerges out of this framework and some progress toward the application of leveraging “Euclidean positivity” in the conformal bootstrap program.”
Join Zoom Meeting: HERE
Meeting ID: 990 0538 0822
Passcode: [REDACTED]

Colloquium - Dr. Sridip Pal
2025-05-07 16:00 - 17:00
Speaker : Dr. Sridip Pal
CALTECH, USA
Title : Aspects of Non-perturbative Conformal Bootstrap
Date : 7th May 2025
Time : 4:00 PM
Venue : Auditorium – New Physical Science Building
Abstract:-
Conformal field theories (CFTs) are special landmarks in the space of Quantum field theories. They sit at the fixed points of the renormalization group flow and describe the physics of systems at critical points. CFTs provide an exact definition of quantum gravity via the holographic principle. Remarkably, the high-energy spectrum of a CFT encodes the physics of black holes, revealing deep insights into quantum gravity.
A powerful non-perturbative approach to understanding CFTs is the conformal bootstrap, which exploits fundamental consistency principles—locality, unitarity, and crossing symmetry—to extract exact results. In this talk, I will demonstrate how the analytical conformal bootstrap yields rigorous universal results about key observables in CFTs, with striking applications to black hole physics and entanglement entropy in statistical mechanics.
Furthermore, I will unveil a novel and profound connection between hyperbolic geometry and the conformal bootstrap. Surprisingly, the same bootstrap techniques that constrain CFTs provide nearly optimal bounds on the spectrum of the Laplacian on compact hyperbolic manifolds, offering a fresh perspective on these spaces as toy models for quantum chaos. This unexpected link opens new avenues for understanding both quantum chaotic systems and the mathematics of hyperbolic manifolds, illustrating the power of modern theoretical physics to bridge seemingly distant domains.
Join Zoom Meeting: HERE
Meeting ID: 955 4348 2615
Passcode: [REDACTED]

Colloquium - Dr. Ajjath Abdul Hameed
2025-05-06 16:00 - 17:00
Speaker : Dr. Ajjath Abdul Hameed
IPPP, Durham, UK
Title : Precision Physics for Particle Colliders
Date : 6th May 2025
Time : 4:00 PM
Venue : Auditorium – New Physical Science Building
Abstract:-
The diverse and complex phenomena we observe in nature stem from physical principles acting at the level of elementary particles. Understanding these building blocks has been a long-standing pursuit. The Standard Model (SM) remains the most successful framework for describing the behaviour of all known non-gravitational particles. Yet, several open questions indicate that it is not a complete theory. While experimental techniques have advanced significantly, direct evidence for physics beyond the SM has yet to emerge. In this context, precision measurements provide an alternative approach to explore new physics indirectly by probing for small deviations from SM predictions. This pursuit relies on advancements in high-energy particle colliders and our ability to perform precise theoretical calculations within the SM. In this colloquium, we will discuss recent developments in precision theory calculations in perturbative quantum chromodynamics, and their role in collider experiments.
Join Zoom Meeting: HERE
Meeting ID: 952 2540 8412
Passcode: [REDACTED]

Seminar - Dr. Pratik Rath
2025-05-06 14:00 - 15:30
Speaker : Dr. Pratik Rath
University of California, Berkeley
Title : Entanglement Negativity and its Holographic Dual
Date : 6th May 2025
Time : 2:00 PM
Venue : LH-3, New Physical Science Building
Abstract:-
The entanglement negativity is a useful measure of quantum entanglement in bipartite mixed states. The holographic dual of this entanglement measure has been controversial with calculations based on CFT techniques conflicting with calculations in random tensor networks (RTNs) that predict replica symmetry breaking. In this talk, I will argue that replica symmetry is broken for general holographic states. The argument involves relating the entanglement negativity to the 1/2 Renyi entropy of a doubled state. In order to compute it holographically, I will also discuss a modified cosmic brane proposal for computing Renyi entropies for n

Colloquium - Dr. Pratik Rath
2025-05-05 16:00 - 17:00
Speaker : Dr. Pratik Rath
University of California, Berkeley
Title : Tensor Networks and Holography: The Quantum Information Road to Quantum Gravity
Date : 5th May 2025
Time : 4:00 PM
Venue : Auditorium – New Physical Science Building
Abstract:-
Holography, the idea that a theory of quantum gravity naturally lives in one lesser dimension, has played a crucial role in our pursuit of a fundamental theory of nature. The AdS/CFT correspondence has given us a concrete setting to explore this idea. In this talk, I will review the progress made in understanding holography using tools from quantum information theory. A key role is played by tensor networks which serve as toy models of holography and elucidate the emergence of spacetime from entanglement. I will review the close connection between tensor networks and gravity via the concept of fixed-area states. I will discuss various applications of this connection including a calculation of the Page curve of black hole evaporation and dualities between various entanglement measures and their corresponding geometric manifestations.
Join Zoom Meeting: https://zoom.us/j/96380902846?pwd=[REDACTED]
Meeting ID: 963 8090 2846
Passcode: [REDACTED]

Gauge-Gravity by the Ghats Seminar (Season 2)
2025-04-09 14:30 - 15:30
Speaker: Oliver Janssen (EPFL, Switzerland)
Title: The no-boundary puzzle: a review and a possible resolution
Abstract: We will review the Hartle-Hawking proposal for the wave function of the universe, which is supposed to provide a theoretical prior on cosmological observables. Puzzlingly, although providing a sensible answer for small fluctuations around an inflationary background, when applied to the background itself, it predicts the curvature of the universe to be large, in contrast with observations. The proposal is based on a semiclassical evaluation of the path integral in quantum gravity, employing complexified solutions. We will then review an “allowability” criterion on saddles based on the convergence of fluctuations around them, and apply it to Hartle-Hawking solutions in the contexts of inflation and spatial anisotropy. We argue this provides a way towards solving the large curvature problem and gives a sharp prior on the prevalence of primordial gravitational waves, in agreement with observations.
Meeting link will updated close to the seminar date

Journeys In Particle Physics - Rohini Godbole Memorial Conference
2025-03-13 09:30 - 2025-03-15 17:00
International Conference in the honour of Late Prof. Rohini M. Godbole.
More Details here

Black Hole Information in Holography and String Theory Conference
2025-02-08 - 2025-02-09
Workshop Discussion Topics:
Black hole physics with emphasis on quantum aspects, black hole microstates in string theory, information paradox, nature of the horizon, black holes in holographic CFTs, bulk locality in holography, and other related questions of current and lasting interest.
Organizers:
Aninda Sinha,
Chethan Krishnan
Justin David.
Registration Fee: INR 4000/- + GST
Registration: HERE
Timetable and other details be updated here : INDICO

SEMINAR
2025-02-03 15:00 - 16:30
Speaker: Godwin Martin (ICTS, Bangalore)
Title: An Exterior Field Theory for Hawking Radiation
Abstract: How should one understand the physics of field theories living around a black hole? We know since Einstein that black holes suck in everything that is thrown at them (dissipation into the black hole). But since Hawking, we also know that black holes radiate (Hawking fluctuations of the black hole). Can one set up a field-theoretic description in the exterior of a black hole accounting for both these effects? I will present an affirmative answer to this question (in a simple setup) and try to explain how the black hole modifies the Feynman rules of the field theory outside.

SEMINAR
2025-01-31 14:30 - 16:00
Speaker: Budhaditya Bhattacharjee, IBS, Daejeon.
Title : Towards a Solvable model with chaotic transition
Abstract :
Understanding chaos in quantum systems is a fundamental problem in quantum physics. A step in this direction is to develop many-body quantum mechanical models that offer significant analytical control and feature chaotic behaviour. While many such models are known in case of either completely chaotic or completely integrable (in the random matrix sense), there is significant interest in developing a solvable, non-trivial model (or non-random-matrix model) that exhibits a transition from a chaotic to integrable phase. I will discuss once such model, which can be solved and demonstrates the transition. I will capture the transition using various probes and discuss the emergent physics that controls the transition. I will then demonstrate the solvability of the model, and outline some interesting features. I will end with discussion on possible future directions.

SEMINAR
2025-01-30 15:00 - 16:30
Speaker: Arvind Shekar (University of Southampton)
Title: Replica analysis of entanglement properties and conditions for islands
Abstract: Entanglement entropy quantifies the degree of entanglement between two quantum systems or between two subregions in a QFT and hence is an important tool to understand the quantum system. However, its study in dimensions $> 2$ has been mostly limited to flat backgrounds and CFT vacuum states in specific subregions due to technical as well as conceptual difficulties. In this talk, I will present a systematic analysis of the properties of entanglement entropy in curved backgrounds using the replica approach. We will explore the analytic $(q-1)$ expansion of Rényi entropy $S_q$ and its variations; the setup applies to generic variations, from symmetry transformations to variations of the background metric or entangling region. Our methodology elegantly reproduces and generalises results from the literature on entanglement entropy in different dimensions, backgrounds, and states. We will then use this analytic expansion to explore the behaviour of entanglement entropy in static black hole backgrounds under specific scaling transformations. We will show that certain conditions on this quantity and hence the QFT spectrum have to be satisfied for the presence of islands of entanglement, which provide enough quantum corrections to restore unitarity in black hole evaporation.

Pheno-Coffee Talk
2025-01-29 14:30 - 16:00
Speaker: Dipan Sengupta (University of New South Wales, Australia)
Date and time: 29th January, Wednesday
Venue: LH-3, Physical Sciences building
Title: Unitarizing scattering amplitudes in theories of compact Extra Dimensions
Abstract: Scattering amplitudes are ubiquitous and paramount to understanding the validity of quantum field theories. In this talk, I will discuss scattering amplitudes of massive spin-2 particles. I will contrast the unitarity violating scales of theories of massive gravity and compact extra dimensions. I will also demonstrate how scattering amplitudes in extra dimensions can be obtained via the double copy prescription that relates gauge theory and gravity amplitudes.

CHEP Colloquium - The cosmological axion domain wall problem
2025-01-27 16:00 - 17:00
Speaker : Prof. Subir Sarkar
University of Oxford, U.K
Title : The cosmological axion domain wall problem
Date : 27th January 2025
Time : 4:00 PM
Venue : Auditorium – New Physical Science Building
Abstract:-
We revisit the domain wall problem for QCD axion models (e.g. DFSZ) with more than one quark charged under the Peccei-Quinn symmetry. If the symmetry breaks after inflation, then axion domain walls form which would cause cosmic catastrophe if they come to dominate the Universe. However the walls are natur ally unstable due to non-renormalisable Planck scale suppressed operators, which generate a ‘tilt’ in the axion potential. Consideration of the axions generated by the collapse of the walls then requires the Peccei-Quinn scale to be quite low (

PHENO-COFFEE TALK
2025-01-27 14:30 - 15:30
Speaker: Tarak Nath Maity (University of Sydney, Australia)
Venue: LH-3, Physical Sciences building
Title: Neutrinos at direct detection: friend or foe?
Abstract: In this talk, we will explore the dual role of neutrinos in direct detection experiments. We will demonstrate how solar neutrinos hinder the search for sub-GeV dark matter through DM-electron scattering. Specifically, we will show that, for DM-electron scattering mediated by heavy particles, solar neutrinos can pose a significant background in certain well-motivated regions of parameter space. Conversely, we will highlight how neutrino events at XENONnT and PandaX-4T are probing the Standard Model’s weak mixing angle in complementary regions—remarkably, at the lowest energy scale to date.

SEMINAR
2025-01-24 14:30 - 16:00
Speaker: Alfio Maurizio Bonanno (INAF and INFN, Catania, Italy)
Title – Dynamical models of regular black holes and singularity resolution from effective quantum spacetimes
Abstract – The study of regular black holes has recently garnered significant attention, driven by the need to extend general relativity to accurately describe black hole interiors and by advances in observational technologies. Despite substantial progress in this field, significant challenges remain in identifying and characterizing physically well-motivated classes of regular black holes. In this talk, I will review recent results in Quantum Einstein Gravity within the framework of Asymptotic Safety, offering a new perspective on this problem and, more broadly, on the resolution of singularities. I will also discuss a new class of dynamically generated regular black holes.

SEMINAR
2025-01-23 15:00 - 16:30
Speaker: Anindita Maiti (Perimeter Institute)
Title – Neural Network Field Theory and Wilsonian RG: Bridging Physics and Machine Learning
Abstract – Machine learning (ML) models have become indispensable tools across diverse domains, including theoretical physics. However, their utility hinges on trustworthiness—precision, interpretability, and robustness—especially in applications to complex physical systems. In this talk, I will present two foundational contributions that aim to bridge physics and machine learning by leveraging concepts from quantum field theory (QFT) and renormalization group (RG) flows. First, I will introduce the Neural Network Field Theory (NNFT) correspondence, which maps neural network (NN) architectures, the backbones of ML, to QFTs. This correspondence provides a framework to embed symmetries and interactions of QFT actions directly into NN architectures at initialization, improving NN interpretability and robustness. By drawing analogies with field interactions, I will show how violations of the Central Limit Theorem (CLT) in NN parameter distributions can be harnessed to design more expressive and physically meaningful models. Second, I will discuss a Wilsonian RG framework for supervised learning performance, which tracks the evolution of noise in NN predictions as data features are coarse-grained. This approach offers a novel perspective on how precision emerges or degrades based on data feature scales, providing theoretical tools to identify regimes of high trustworthiness in ML outputs. By integrating these insights, this talk demonstrates how theoretical physics not only inspires but also fundamentally reshapes the design and understanding of machine learning models.

CHEP Colloquium - Prof. Tracy Slatyer
2025-01-22 16:00 - 17:30
Speaker : Prof. Tracy Slatyer
Department of Physics, MIT
Title : Dark Matter, Cosmic Background Radiation, and the Birth of the First Stars
Date : 22nd January 2025
Abstract:-
84% of the matter in the universe is “dark”, presently invisible to us except through its gravitational interactions. However, even tiny interactions between dark and visible matter could have striking effects on the primordial history of our universe, and leave distinctive traces of their existence in the low-energy background photons that pervade the cosmos. I will present recent work mapping out the space of such signals that could be produced by dark matter decay and annihilation, and furthermore discuss how such energy injections could influence the formation of the first stars in the universe.

Institute Lecture - Prof. Tracy Slatyer
2025-01-16 16:00 - 17:30
Speaker:
Prof. Tracy Slatyer
Satish Dhawan Visiting Chair Professor, CHEP, IISc
MIT Department of Physics, Cambridge, United States
Title: Searching for Dark Matter with the Universe’s Highest-Energy Light
Abstract:
Gamma rays, with frequencies billions of times higher than visible light, provide a window on extremely energetic astrophysical processes occurring in our Milky Way Galaxy and beyond. At the same time, the mysterious dark matter of the universe could imprint a range of clues to its existence in the gamma-ray sky. Disentangling the two isn’t always easy, but I will discuss how physicists try to distinguish possible dark matter signals from high-energy astrophysics, what we are currently seeing in the data, and what new clues the next generation of gamma-ray telescopes are expected to provide.

Pheno-Coffee Talk
2025-01-13 14:30 - 16:00
Speaker: Rohan Pramanick (Indian Association for the Cultivation of Science, Kolkata)
Title: Simultaneous generation of visible and dark matter in the vanilla Scotogenic model
Abstract: We explore the possibility of generating both the visible and dark matter in the well motivated scotogenic neutrino mass model. The CP violating decay of a heavy Z_2 odd right handed neutrino (RHN) populates the visible sector through leptogenesis while simultaneously generating a multipartite dark sector. The relic abundance of dark matter is determined by the sub-GeV scale lightest RHN produced via freeze-in mechanism which is dynamically regulated by the interplay between the delayed decay and thermal scatterings of the next-to-lightest dark particle.

Seminar
2025-01-09 14:30 - 16:00
Speaker: Srijit Paul, University of Maryland.
Title: Hadronic vacuum polarization discrepancy between lattice QCD and data-driven approaches and one possible new physics scenario
Abstract:
We present the latest lattice results for the hadronic vacuum polarization from lattice QCD. In order to isolate the different origin of systematic errors in lattice computations, the observable is decomposed into several windows. The latest discrepancy between the data-driven theory prediction of the intermediate and long distance window of the hadronic vacuum polarization using the experimental input of e+e- to hadrons cross-section and the lattice predictions have sparked several new physics scenarios. We elaborate on the Mainz results for the intermediate and long distance windows and discuss the implications of the discrepancy. The anomalous magnetic moment of the muon (aµ) provides a stringent test of the Standard Model and Beyond, that too, interestingly on two independent fronts: the “aµ-test” and the “HVP-test”.We discuss a generic, light (∼ 100 MeV-1 GeV) Z′’s impact on both these tests in multiple ways making this arena an excellent probe of such models.

Pheno-Coffee Talk
2025-01-08 16:00 - 17:30
Speaker: Subhendra Mohanty (Indian Institute of Technology Kanpur, India)
Title: Effective theories at finite temperature
Abstract: Effective theories offer an economical way to test the predictions of diverse UV complete theories in low energy experiments. The finite temperature formulation of effective theories is needed for applications in cosmology and collider experiments in phase transitions, quark gluon plasma, Casimir effect etc. I will discuss a way to formulate effective theories at finite temperature using the Heat Kernel Method which involves the calculation of finite temperature corrections to the Wilson coefficients. I will illustrate the results with a calculation of Coleman-Weinberg potential for the Higgs-Effective field theory and apply it in testing the nature of phase transition from different extensions of the standard model. Of particular interest is the emergence of Polyakov loops as a parameter which has applications in phase transitions and spin-systems in condensed matter.

Pheno-Coffee Talk
2025-01-08 14:30 - 16:00
Speaker: P. S. Bhupal Dev (Washington University in St. Louis, U.S.A.)
Title: Neutrinos: Dirac or Majorana?
Abstract: Whether neutrinos are Dirac or Majorana particles is an open question in fundamental physics. Theoretically, it is also possible that neutrinos are pseudo-Dirac, which are fundamentally Majorana fermions, but essentially act like Dirac fermions in most experimental settings, due to extremely small active-sterile mass splitting. Such small values of mass splitting can be accessed via active-sterile oscillations over astrophysical baselines. We use the recent multi-messenger observations of high-energy neutrino sources to probe hitherto unexplored values of active-sterile mass splitting, which improve the reach of terrestrial experiments by more than a billion.

Pheno-Coffee Talk
2025-01-07 14:30 - 16:00
Speaker: Abhishek Mohapatra (Technical University Munich, Germany)
Title: One Born Oppenheimer Effective Theory to rule all Exotics
Abstract: The XYZ exotic states discovered in the hadronic sector with two heavy quarks constitute one of the most important open problems in particle theory. In this talk, I show that an effective field theory derived from QCD, the Born Oppenheimer effective field theory (BOEFT), can describe exotics of any composition. I show the results of general Schr”odinger coupled equations for arbitrary angular momentum of the light degrees of freedom. The coupled equations describe hybrids, tetraquarks, pentaquarks, doubly heavy baryons, and quarkonia in leading order, including nonadiabatic terms. Additionally, I also present the results of the predicted multiplets, corresponding selection rules, and expressions of the nonperturbative gauge invariant correlators, which are the input of the BOEFT: static energies, generalized Wilson loops, gluelumps, and adjoint mesons that should be calculated on the lattice. Moreover, I show for the first time new results on the behavior of static energies at short distances and mixing with the threshold at long distances based on BOEFT. As an application of this BOEFT, I show results for the hybrid spectrum, hybrid decays to quarkonium and some preliminary results for X(3872) and T_cc (3875).
