Amitava Raychaudhuri

Research Summary: In 2007-08, research has been carried out in aspects of neutrino , models based on space-time with extra dimensions, and quark models. In continuing work on the prospects of the proposed Iron Calorimeter detector at INO being used as an end-detector for a very long baseline experiment in con- junction with a beta-beam source in Europe, it has been shown that this set-up has unmatched sensitivity for probing many of the remaining unknowns of the neutrino mass matrix. Related work on long baseline experiments with a beta- beam have (a) explored the possibility of using the survival probability Pee and (b) optimised the baseline, boost-factor, and luminosities for the best reach for probing the open issues of neutrino physics. The upper bound on the mass of the lightest neutral higgs scalar is shown to be considerably relaxed in models in which SUSY is embedded in space-time of more than four dimensions. Even though the observational evidence for the ‘pentaquark’ is currently not strong, such a bound state is a consequence of QCD. The group theory of the ‘triquark’ – which is a aconstitutent of the pentaquark – has been examined with a focus on the colour-spin SU(6) structure. Using these results, the masses of the different pentaquak states and their colour-spin excitations have been estimated.

Publications:

1. Sanjib Kumar Agarwalla, Sandhya Choubey, Srubabati Goswami, and Ami- tava Raychaudhuri, Neutrino parameters from matter effects in Pee at long base- lines, Phys. Rev. D75, 097302 (2007)

2. Abhijit Samanta, Sudeb Bhattacharya, Ambar Ghosal, Kamales Kar, Deba- sish Majumdar, and Amitava Raychaudhuri, A GEANT-based study of atmo- spheric neutrino oscillation parameters at INO, Int. J. Mod. Phys. A23, 233-245 (2008)

3. Gautam Bhattacharyya, Swarup Kumar Majee, and Amitava Raychaud- huri, Extra-dimensional relaxation of the upper limit of the lightest supersymmet- ric neutral Higgs mass, Nucl. Phys. B793, 114-130 (2008)

1 Preprints:

1. S. K. Agarwalla, S. Choubey and A. Raychaudhuri, Magic Baseline Beta Beam, AIP Conf. Proc. 939, 265 (2007) arXiv:0707.3367 [hep-ph]

2. Sanjib Kumar Agarwalla, Sandhya Choubey and Amitava Raychaudhuri, Unraveling neutrino parameters with a magical beta-beam experiment at INO, arXiv:0711.1459 [hep-ph] Nucl. Phys. B (to appear)

3. Swarup Kumar Majee and Amitava Raychaudhuri, SU(6), Triquark states, and the Pentaquark, arXiv:0711.3910 [hep-ph] Phys. Rev. (to appear)

4. S. K. Agarwalla, S. Choubey and A. Raychaudhuri, Physics with Beta-Beam, AIP Conf. Proc. 981, 84 (2008) arXiv:0712.4072 [hep-ph]

5. S. K. Agarwalla, S. Choubey, A. Raychaudhuri and W. Winter, Optimizing the greenfield Beta-beam, arXiv:0802.3621 [hep-ex]

Conference/Workshops Attended:

1. HEPCOS 2008, Jamia Millia Islamia, New Delhi, March, 2008.

2. Higgs Hunters’ Meeting, Visva-Bharati, Santiniketan, February, 2008.

3. Theophys-2007, ISI, , December, 2007.

4. KEK-INO Meeting, KEK, Japan, November, 2007.

5. Indian Academy of Sciences Mid-Year Meeting, Bangalore, July, 2007.

6. BCSPIN 2007, GUCAS, Beijing, China, June, 2007.

7. Workshop on Possible Partiy Restoration at High Energies, IHEP, Beijing, China, June, 2007.

Visits to other Institutes:

1. Center for High Energy Physics, Peking University, Beijing, China, June, 2007.

Invited Lectures/Seminars:

1. Neutrino physics and INO, HEPCOS 2008, Center for , Jamia Millia Islamia, New Delhi, March, 2008.

2 2. Extra-dimensional limits on the Higgs mass from vacuum stability and triviality, Higgs Hunters’ Meeting, Visva-Bharati, Santiniketan, February, 2008.

3. Nuances of Neutrinos, Theophys-2007, ISI, Kolkata, December, 2007.

4. Physics with INO, KEK-INO Meeting, KEK, Japan, November, 2007.

5. Nuances of Neutrinos, Refresher Course in Physics, , September, 2007.

6. Let’s talk about INO, Indian Academy of Sciences Mid-Year Meeting, Banga- lore, July, 2007.

7. The -based Neutrino Observatory: Status and Physics Prospects, BCSPIN 2007, Beijing, China, June, 2007.

8. Relaxing the lightest SUSY higgs mass via extra-dimensions, Kavli Institute, Bei- jing, China, June, 2007.

9. Extra-dimensional relaxation of the mass limit of the lightest neutral SUSY higgs, Centre for High Energy Physics, Peking University, Beijing, China, June, 2007.

10. Low intermediate scales in SUSY SO(10) GUTs with left-right symmetry, Work- shop on Possible Parity Restortion at High Energies, IHEP, Beijing, China, June, 2007.

11. The Particle Play, KVPY Summer Programme, HRI, , May, 2007.

12. Modeling the Building Blocks of the Universe, Mathematical Modeling and its Engineering Applications, B.P. Poddar Institute of Management and Tech- nology, Kolkata, April, 2007.

Other Activities:

1. Member, Physical Sciences Subject Expert Committee for the FIST Programme, Department of Science and Technology, Govt. of India.

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