SAHA INSTITUTE OF NUCLEAR PHYSICS, CALCUTTA

Theory Division Seminars



Date: 01 Jan 1970 Thursday
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Date: 19 Dec 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Yet Another Era of Charm Physics
Speaker: Ayan Paul
Affiliation: Dept. of Physics, University of Notre Dame du Lac
Abstract: The role of charm in establishing the Standard Model is unquestionable. Yet, a large part of the dynamics of its bound states has been inaccessible to experimental test. With the advent of the new flavour factories and very high luminosity experiments, times seem to have changed. As extensive studies of charm dynamics is now starting to become an experimental reality, it is necessary to replicate the same on the theoretical front. Moreover, Nature\'s Grand Design seems to be more elusive than previously contemplated, and hence, it becomes increasingly necessary to probe all alleys for signs of New Dynamics. I shall present our partially model independent correlated studies of the latter in charm dynamics and shed light on a different perspective in model building.

Date: 14 Nov 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: 5-dimensional Super-Yang-Mills and M5-branes
Speaker: Harvendra Singh
Affiliation: SINP
Abstract: The M5-branes are magnetically dual cousins of M2-branes. But writing down an interacting field theory for multiple M5-branes has remained an elusive goal so far. Recent constructions of various membrane theories, such as ABJM and BLG Chern-Simons matter theories, have led to some understading that gauge-fields are the vital building blocks in M-theory as well. I shall present an unique way to uplift the cosmetic structure of 5D SYM to a 6-dimensional framework. The new 6-dimensional gauge theory acquires scale invariance.

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Date: 20 Oct 2011 Thursday
Time: 15 : 30
Place: Room 3307
Title: Higher Spin Cousins of Topologically Massive Gravity and Their Curious Dual CFTs
Speaker: Arjun Bagchi
Affiliation: University of Edinburgh, UK

Date: 29 Sep 2011 Thursday
Time: 15 : 30
Place: Room 3307
Title: UNIFICATION OF FORCES AND THE EVOLUTION OF THE UNIVERSE
Speaker: Jogesh C. Pati
Affiliation: University of Maryland

Date: 05 Sep 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Restoration of chiral symmetry and self energy calculation on lattice
Speaker: Anwesa Sarkar
Affiliation: SINP

Date: 02 Sep 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: Light Hadron Spectroscopy with Dynamical Wilson Fermions
Speaker: Sangita De Sarkar
Affiliation: SINP

Date: 10 Aug 2011 Wednesday
Time: 15 : 30
Place: Room 3307
Title: Calculation of the temperature associated with a horizon
Speaker: Bhramar Chatterjee
Affiliation: SINP

Date: 01 Jan 1970 Thursday
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Date: 28 Jul 2011 Thursday
Time: 15 : 30
Place: Room 3307
Title: Models of Slow-roll Inflation
Speaker: Arindam Mazumdar
Affiliation: SINP

Date: 25 Jul 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Black holes and asymptotic symmetries
Speaker: Avirup Ghosh
Affiliation: SINP

Date: 25 Jul 2011 Monday
Time: 15 : 00
Place: Room 3307
Title: Back-reaction in FRW cosmology
Speaker: Atanu Kumar
Affiliation: SINP

Date: 22 Jul 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: The constrained MSSM confronted with the low energy data
Speaker: Diptimoy Ghosh
Affiliation: TIFR
Abstract: The recent Belle and BaBar measurements of the branching ratio of B + → τ + ντ indicate a significant deviation from the Standard Model prediction. I will demonstrate that this measurement has a serious impact on models with minimal flavor violation involving a charged Higgs boson, ruling out a large portion of the currently-allowed parameter space. In the constrained minimal supersymmetric standard model, this creates a tension between the measurements of B + → τ + ντ and the anomalous magnetic moment of the muon, unless tan β is small, μ > 0, and A0 takes a large negative value. In fact, a very small region of the parameter space of this model, with small values of m0 and m1/2, survives all the constraints at 95% C.L.. It is remarkable that this specific region is still consistent with the lightest supersymmetric particle as the dark matter. Moreover, it predicts observable SUSY signals in the early runs of the LHC, even perhaps at 7 TeV. I will also show that a consistent explanation for the deviation of the B + → τ +ντ branching ratio from the Standard Model can be achieved in a non-universal Higgs mass model, which could also predict early signals of supersymmetry at the LHC.

Date: 20 Jul 2011 Wednesday
Time: 15 : 30
Place: Room 3307
Title: Orthogonality of eigenfunctions of $D_N$-type Calogero model and quasi-Hermiticity
Speaker: Pratyay Banerjee
Affiliation: SINP

Date: 18 Jul 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Non-relativistic branes
Speaker: Parijat Dey
Affiliation: SINP

Date: 15 Jul 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: \"Hints of Integrability Beyond the Planar Limit\"
Speaker: Tanay K. Dey
Affiliation: Witwatersrand Univ, South America
Abstract: The problem of computing the anomalous dimensions of a class of (nearly) half-BPS operators with a large R-charge of order N^2 is reduced to the problem of diagonalizing a Cuntz oscillator chain. Due to the large dimension of the operators we consider, non-planar corrections must be summed to correctly construct the Cuntz oscillator dynamics. These non-planar corrections do not represent quantum corrections in the dual gravitational theory, but rather, they account for the backreaction from the heavy operator whose dimension we study. Non-planar corrections accounting for quantum corrections seem to spoil integrability, in general. It is interesting to ask if non-planar corrections that account for the backreaction also spoil integrability. We find a limit in which our Cuntz chain continues to admit extra conserved charges suggesting that integrability might survive.

Date: 11 Jul 2011 Monday
Time: 15 : 45
Place: Room 3307
Title: Topological Susceptibility in lattice QCD with unimproved Wilson fermion
Speaker: Santanu Mondal
Affiliation: SINP

Date: 11 Jul 2011 Monday
Time: 15 : 00
Place: Room 3307
Title: Topological charge in LQCD with Wilson fermion
Speaker: Abhishek Chowdhury
Affiliation: SINP

Date: 08 Jul 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: Periodic boundary condition for a quantum integrable system with non-cubical configuration space
Speaker: Bireswar Basu-Mallick
Affiliation: SINP
Abstract: Configuration spaces of some quantum integrable systems with singular interactions can be determined by analysing the nature of such singularity. In this talk, we discuss how the interactions of spin Sutherland model associated with the $D_N$ type of root system lead to a Weyl-invariant configuration space, which is a $N$-dimensional generalization of the rhombic dodecahedron. Imposing periodic boundary condition on this nontrivial configuration space, we derive the spectrum of spin Sutherland model of $D_N$ type. Applying the freezing trick, subsequently we obtain an exact expression for the partition function of the related Haldane-Shastry type spin chain.

Date: 06 Jul 2011 Wednesday
Time: 15 : 30
Place: Room 3307
Title: Dissipative force on an external quark in heavy quark cloud
Speaker: Shankhadeep Chakrabortty
Affiliation: IOP Bhubaneswar

Date: 04 Jul 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Extra Dimension Signal at the LHC upto NLO
Speaker: Satyajit Seth
Affiliation: SINP

Date: 30 Jun 2011 Thursday
Time: 15 : 30
Place: Room 3307
Title: \"Generalisation of Gunion-Bertsch Formula for Soft Gluon Emission\"
Speaker: Raktim Abir
Affiliation: SINP

Date: 29 Jun 2011 Wednesday
Time: 16 : 00
Place: Room 3307
Title: Low-mass dilepton rate from the deconfined phase
Speaker: Najmul Haque
Affiliation: SINP

Date: 29 Jun 2011 Wednesday
Time: 15 : 30
Place: Room 3307
Title: Analysis of vector correlation function and its spectral representation: Some properties of QGP in pQCD and LQCD
Speaker: Munshi Golam Mustafa
Affiliation: SINP

Date: 24 Jun 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: Jet substructure and new physics searches at the LHC
Speaker: Biplob Bhattacherjee
Affiliation: Visiting Fellow, TIFR
Abstract: Top quarks produced from the decay of a heavy particle will have large boost and their decay products will be highly collimated. The conventional search techniques will not work in this case. At the LHC, a generic supersymmetric cascade can be a source of boosted top quark. We have shown that the recently proposed jet substructure algorithm can be very useful in identifying such boosted top quarks in the cascade.

Date: 22 Jun 2011 Wednesday
Time: 15 : 45
Place: Room 3307
Title: Coulomb impurity in graphene in the presence of a topological defect
Speaker: Baishali Chakraborty
Affiliation: SINP

Date: 22 Jun 2011 Wednesday
Time: 15 : 00
Place: Room 3307
Title: Jet quenching parameter in Yang-Mills theories
Speaker: Somdeb Chakraborty
Affiliation: SINP

Date: 14 Jun 2011 Tuesday
Time: 15 : 30
Place: Room 3307
Title: The saga of van der Waals: From black holes to boiling water
Speaker: Tapobrata Sarkar
Affiliation: IIT, Kanpur

Date: 13 Jun 2011 Monday
Time: 15 : 00
Place: Room 3307
Title: Wilson loop from AdS/CFT
Speaker: Shibaji Roy
Affiliation: SINP

Date: 10 Jun 2011 Friday
Time: 15 : 00
Place: Room 3307
Title: Fluctuations and logarithmic corrections to black hole entropy
Speaker: Tapobrata Sarkar
Affiliation: IIT, Kanpur

Date: 06 Jun 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: What are Majorana fermions?
Speaker: Palash Baran Pal
Affiliation: SINP

Date: 06 Jun 2011 Monday
Time: 15 : 00
Place: Room 3307
Title: Constraints on the choices of U(1) R-charges in generic and calculable models
Speaker: Pritibhajan Byakti
Affiliation: SINP

Date: 17 May 2011 Tuesday
Time: 15 : 30
Place: Room 3307
Title: Pseudo-Hermitian Quantum Systems : a Deconstruction
Speaker: Prof. Pijush K. Ghosh
Affiliation: Visva-Bharati University

Date: 01 Jan 1970 Thursday
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Date: 21 Apr 2011 Thursday
Time: 15 : 30
Place: Room 3307
Title: Detecting Physics Beyond the Standard Model through b → s μ + μ− transition
Speaker: Diptimoy Ghosh
Affiliation: Tata Institute of Fundamental Research, Mumbai
Abstract: The Flavor sector of the Standard Model has recently seen some discrepancies with the experimental measurements from the Tevatron experiments CDF and DØ, and to a smaller extent the B factories Belle and BaBar. Interestingly, many of these ”anomalies” are in the b → s transition sector of the Standard Model. I will briefly discuss some of the existing anomalies and elaborate how model independently we can try to detect the structure of the underlying New Physics beyond the Standard Model

Date: 01 Jan 1970 Thursday
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Date: 11 Apr 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: A large N dual to 2d CFTs
Speaker: Prof. Rajesh Gopakumar
Affiliation: HRI, Allahabad
Abstract: We describe how higher spin theories in AdS might be dual to interesting non-supersymmetric CFTs. We illustrate this with the example of a theory on AdS_3 which is conjectured to be equivalent to a 2d CFT with W_N symmetry (in the large N limit).

Date: 04 Apr 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Recursion Relations for AdS/CFT Correlators
Speaker: Suvrat Raju
Affiliation: HRI, Allahabad
Abstract: Correlation functions in the gauge-gravity correspondence (AdS/CFT) are dual to scattering amplitudes in anti-de Sitter space (AdS). In this talk, I will describe how techniques that were recently developed to study scattering amplitudes in flat space can be generalized to AdS leading to a new and efficient method of computing correlation functions in AdS/CFT. CONTEXT: The past few years have seen an intense study of the Britto-Cachazo-Feng-Witten (BCFW) recursion relations for scattering amplitudes in gauge and gravity theories in flat space. These recursion relations are of interest for two reasons. First, they provide a new approach, which is far more efficient than the evaluation of Feynman diagrams, to the computation of amplitudes including those that are of phenomenological interest at particle accelerators. More fundamentally, these recursion relations have been investigated to try and find an alternate formulation of quantum field theory.

Date: 28 Feb 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: Black holes and the positive cosmological constant
Speaker: Sourav Bhattacharya
Affiliation: S.N. Bose National Centre for Basic Sciences
Abstract: In this talk I shall address some features of black hole spacetimes in presence of a positive cosmological constant. I shall discuss the general criterion for a cosmological Killing horizon to exist and the generalization of classical no hair and uniqueness problems in such spacetimes. I shall also briefly mention some of our other works and future directions in this field.

Date: 17 Feb 2011 Thursday
Time: 16 : 00
Place: Room 3307
Title: High Energy Gamma Ray Astronomy with the High Altitude GAmma Ray (HAGAR) telescope array in the Himalayas
Speaker: R. J. Britto
Affiliation: Tata Institute of Fundamental Research, Mumbai
Abstract: The High Altitude GAmma-Ray (HAGAR) experiment is a wavefront sampling array of 7 telescopes, using the atmospheric Cherenkov technique, set up at Hanle, at 4270 m amsl, in the Ladakh region of the Himalayas. It constitutes the first phase of the HImalayan Gamma-Ray Observatory (HIGRO) project, and is sensitive to gamma rays from ~200 GeV. Regular source observations are running since Sept. 2008. We have collected more than 80 hrs of data from Crab nebula, which is the standard candle source of TeV gamma-ray astronomy, and more than 60 hrs of data from OFF-source regions, for estimation of statistical fluctuations and systematics in our data/analysis. After an introduction to gamma-ray astronomy, I will present preliminary results and discuss our analysis procedures.

Date: 14 Feb 2011 Monday
Time: 15 : 00
Place: Room 3307
Title: Neutrino parameters : upcoming experiments and future facilities
Speaker: Sanjib Kumar Agarwalla
Affiliation: Instituto de Física Corpuscular, CSIC-Universitat de Valencia
Abstract: First of all, we will take a look at our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. Then we will discuss the physics reach of the upcoming reactor and accelerator neutrino oscillation experiments in addressing these unsolved issues. Next, we will focus on our work in the context of the proposed Fermilab based Long Baseline Neutrino Experiment (LBNE) which in future can enhance our knowledge of neutrino oscillations well beyond what can be anticipated from ongoing and planned experiments worldwide. Here we would like to suggest a new strategy to replace the anti-neutrino run of LBNE, with anti-neutrinos from muon decay at rest. The resulting discovery reaches in $\\theta_{13}$, the mass ordering and leptonic CP violation will be compared with those from a conventional superbeam experiment with combined neutrino and anti-neutrino running.

Date: 10 Feb 2011 Thursday
Time: 16 : 00
Place: Room 3307
Title: Double Beta Decay Study of Some Promising Beta Minus and Positron Mixed Mode Nuclei
Speaker: Surja Kiran Ghorui
Affiliation: Department of Physics & Meterology, Indian Institute of Technology Kharagpur

Date: 07 Feb 2011 Monday
Time: 15 : 30
Place: Room 3307
Title: String theory, Holography and Condensed matter systems
Speaker: Pallab Basu
Affiliation: University of Kentucky, USA
Abstract: We start with a quick introduction of string theory. Then we move to holography (AdS/CFT or gauge-gravity duality). We discuss how gauge-gravity duality works and how we can study a gravity theory to explore gauge theoretic phenomena. As examples, we discuss holographic realization of superfluid/superconductivity and also non-fermi liquids. We end by discussing my current works including non-integrability and chaotic dynamics in the context of holography.

Date: 14 Jan 2011 Friday
Time: 15 : 30
Place: Room 3307
Title: Holographic hydrodynamics
Speaker: Subhankar Dutta
Affiliation: University of Swansea, UK

Date: 13 Jan 2011 Thursday
Time: 16 : 00
Place: Room 3307
Title: 10+1 to 3+1 in an Early Universe with mutually BPS Intersecting Branes
Speaker: Samrat Bhowmick
Affiliation: IMSc, Chennai