Research

"Time is without beginning or end." (Aryabhatta beyond Astronomy)

Research interests

The area of my research work is Cosmology, High Energy Physics and Astrophysics.

I work in Early Universe Cosmology - in particular, inflationary cosmology - primordial gravitational wave production during inflation, modified gravity theory and it's application, bouncing and emergent cosmology.
I am also interested to look for signatures for dark matter - in particular the role of fermion dark matter in the supernova SN1987A cooling and the signature of dark matter in high energy collision (proton-proton LHC, CERN, electron-positron ILC colliders).
My group is also trying to understand the Neutron star properties by studying its EoS with the help of Gravitational wave data produced due to NS-NS binary merger using the LIGO data.

# Group research click

# Research Publication click.

# Statistics: h-index and i10-index of my publication: click here.

Cosmology

The Universe that we see today is largely isotropic and homogeneous over a large scale and it is a widely accepted idea that the Universe in it's very beginning must have passed through an exponential accelerated expansion - called inflation. A host of inflationary model for inflationary expansion, the observable signatures of inflationary perturbations, its effects on cosmic microwave background radiation(CMBR) etc are worthwhile to investigate. The gravitational waves generated due to inflationary perturbations or in post inflationary period from the merger of black holes, neutron stars have drawn attention in the cosmology community over a period of time.

Group activities:

To study a inflationary cosmology, bouncing and emerging cosmology using a class of modified gravity theory.
To study the gravitational waves generated due to inflationary perturbations or in post inflationary period from the merger of BH-NS, NS-NS and BH-BH mergers.
To study the time delay lensing in multiple images which may be caused by some supermassive black holes

Group members: Payel, Ashmita, Premananda, Ajith P(ICTS, TIFR, Bangalore), G C Samanta(Fakir Mohan University)

Astrophysics

In 1987 a supernova (SN1987A) was observed in a nearby galaxy called the Large Magellanic Cloud which was produced by the collapse of the star core. The energy liberated in SN1987A explosion was as large as the visible-light luminosity of the entire universe. The kinetic energy of the explosion carries about 1% of the gravitational binding energy of about ergs and the remaining 99% going into neutrinos. This powerful and detectable neutrino burst is the main astrophysical interest of the core-collapse supernovae. Now the numerical neutrino light curves can be compared with the SN1987A data where the measured energies are found to be “too low”. It is remain unclear whether this anomaly is due to a statistical problem or whether there is some New Physics.

Group activities:

In models of extra spatial dimension(s), we have investigated the production of light KK graviton or radion produced inside the supernovae core due to the nucleon-nucleon bremstrahlung,electron-positron and plasmon-plasmon(photons inside plasma become massive, called plasmon ) annihilation, which can take away energy released in the SNe explosion. This in turn put constraints on the size of the extra dimension.
In a collaboration with Dr. Bhupal S Deb, Washington University, USA, we have recently worked on the role of leptophillic dark matter on the relic density, SN1987A cooling and free-streaming from the supernovae core. Another work is going.

Group members: Manish, Saumyen, Bhupal Dev.

High Energy Physics:

Age-old question - How the world is made of by the subatomic particles e.g. quarks, electrons, neutrinos and how they interact with each other? It's answer stems from a model called the Glashow-Weinberg-Salam model or Standard model of Particle Physics. The Weinberg-Salam model has been experimentally tested to a very high degree of precission. The last missing link of the Standard Model - the Higgs boson (which gives masses to everything in the Universe) was discovered on 4th July, 2012. Despite the enormous successes that the Standard Model succumbs, it faces few problems like Hierarchy problem, flavour problem, neutrino mass, dark matter etc. This forces one to think whether there is anything beyond the Standard Model, a New Physics ! If Yes, what is the scale of this New Physics, how it looks like? Can we probe them at high energy particle accelerators or in astrophysical/cosmological laboratories?

Dark matter which constitutes 25% of the net energy-matter budget of the Universe, played a very crucial role in explaining galaxy rotation curve, in large scale structure formation etc. However, it mass, spin, parity are not understood properly till date. To throw light on this dark side of the universe is the key driving force of many collider and astrophysical studies at present.

Group activities:

Recently, we have completed one work on looking for the signature of leptophillic dark matter at TeV energy collision at electron-positron collider(Linear Collider) (with Dr. Bhupal S Deb, Washington University, USA). Status: Communicated to PRD.
We are looking for a dark matter in a singlet-doublet DM model using jet-substructure technique at high energy proton-proton(Large Hadron Collider) collider (with Dr. Partha Konar, Sudipta Sow, PRL, Ahmedabad). Status: Ongoing.
In another work we are looking for the exotic quark at LHC (with Dr. K C Kong, University of Kansas, USA).
To look for the signatures of extra dimension, spacetime noncommutativity, supersymmetry at LHC and Linear Collider

Group members: Saumyen, Bhupal Dev,Partha Konar, K C Kong.

Research publication: click

Research collaborators:

Present:

1. Dr. Bhupal Dev, Washington University, USA

2. Dr. K C Kong, University of Kansas, USA

3. Dr. Douglas Mckay, University of Kansas, USA

4. Dr. Partha Konar, PRL Ahmedabad

5. Dr. Ajith P, ICTS, TIFR, Bangalore

6. Dr. G C Samanta, Department of Mathematics, Fakir Mohan University, Odisha

7. Dr. Santosh Kr. Rai, HRI Allahabad

Past:

8. Dr. Ravi Manohar, University of Mumbai

9. Dr. N G Deshpane, University of Oregon, USA

10. Dr. K C Yang, CYCU, Taiwan, ROC

11. Dr. Pankaj Jain, IIT Kanpur

12. Dr. Sreerup Raychaudhuri, TIFR, Mumbai

13. Dr. Biswarup Mukhopadhyay, HRI, RECAPP, Allahabad

14. Dr. Uma Mohanta(Late), HRI, Allahabad

15. Dr. G. Rajasekaran, CMI, Chennai

16. Dr. S. Garg, IMSc Chennai

17. Dr. Anupam Mitra, BITS-Goa ex student, Ph.D. at ISI Kolkata.

18. Dr. Abhishodh Prakash(ex BITS Goa student),Ph.D. at Stonybrook, NY, USA.

19. Dr. V H Satheeshkumar (Instituto de Fisica,Rio de Janeiro, Brazil)

High Energy software packages: micrOMEGA, CalcHEP, LanHEP, FeynRule, MadGraph, Pythia, Feyncalc, Looptools

Other resources: Useful archive for papers, reviews, monographs and software related to High Energy Physics, Astrophysics, visit (i) LANL, (ii) Slac-Spires, (iii) NetAdvance, (iv) NeuUnb.

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Science is the belief in the ignorance of experts

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