Browsing Prof. Sibaji Raha, Director by Issue Date

Now showing items 1-14 of 14

    • ρ-mass modification in 3He: Signal of restoration of chiral symmetry or test for nuclear matter models? 

      Bhattacharyya, Abhijit; Ghosh, Sanjay Kumar; Raha, Sibaji (American Physical Society, 1999-06-16)
      Two recent experiments have demonstrated that the effective ρ-mass in nuclear medium, as extracted from the 3He(γ,π+π-) reaction, is substantially reduced. This has been advocated as an indication of partial restoration ...

    • Relics of the cosmological QCD phase transition 

      Bhattacharyya, Abhijit; Alam, Jan-e; Sarkar, Sourav; Roy, Pradip; Sinha, Bikash; Raha, Sibaji; Bhattacharjee, Pijushpani (American Physical Society, 2000-03-16)
      The abundance and size distribution of quark nuggets (QN’s), formed a few microseconds after the big bang due to a first-order QCD phase transition in the early universe, has been estimated. It appears that stable QN’s ...

    • Strange Quark Matter in Cosmic Ray Flux and Exotic Events 

      Banerjee, Shibaji; Ghosh, Sanjay Kumar; Mazumdar, Amal; Raha, Sibaji; Syam, Debapriyo (Kluwer Academic Publishers, 2000-11-01)
      There have been several reports of exotic nuclear fragments, with highly unusual charge to mass ratio, in cosmic ray experiments. Although there exist experimental uncertainties which make them, at best, only candidate ...

    • The Cosmic QCD Phase Transition, Quasi-baryonic Dark Matter and Massive Compact Halo Objects 

      Banerjee, Shibaji; Bhattacharyya, Abhijit; Ghosh, Sanjay Kumar; Raha, Sibaji; Sinha, Bikash; Hiroshi, Toki (arXiv.org, 2002-06-20)
      We propose that the cold dark matter (CDM) is composed entirely of quark matter, arising from a cosmic quark-hadron transition. We denote this phase as "quasibaryonic", distinct from the usual baryons. We show that compact ...

    • Characterization of a polymer as a heavy ion detector 

      Basu, B.; Fischer, B.; Mazumdar, A.; Raha, Sibaji; Saha, S.; Saha, Swapan K.; Syam, D. (TATA INST FUNDAMENTAL RESEARCH, 2005)
      A particular brand of polymer, commonly used as overhead projector transparencies, has been used as a solid state nuclear track detector with Z/beta > 35. From the infra-red transmission spectrum by FTIR Spectrophotometer, ...

    • A highly unusual cosmic ray event at mountain altitude 

      Basu, B.; Biswas, S.; Dey, S.; Mazumdar, A.; Raha, Sibaji; Saha, Swapan K. (TATA INST FUNDAMENTAL RESEARCH, 2005)
      Search of rare massive particles in cosmic rays became an active field of research for several years. A recent theoretical study suggested the possible existence of strangelets in cosmic rays even at the mountain altitude. ...

    • Characterization of some commercial polymers for the detection of massive cosmic ray particles 

      Basu, Basudhara; Mazumdar, A.; Raha, Sibaji; Saha, S.; Saha, Swapan K.; Syam, D. (INDIAN ASSOC CULTIVATION SCIENCE, 2005-03-01)
      A particular brand (CENTURY de'Smat, India) of overhead projector (OHP) film has been exposed to α-particle and fission fragments from 252Cf natural source in order to investigate its detection efficiency and charge ...

    • Strangeness, cosmological cold dark matter and dark energy 

      Raha, Sibaji; Banerjee, S.; Bhattacharyya, A.; Ghosh, Sanjay Kumar; Ilgenfritz, E. M.; Sinha, B.; Takasugi, E.; Toki, H. (IOP PUBLISHING LTD, 2005-06-01)
      It is now believed that the universe is composed of a small amount of the normal luminous matter, a substantial amount of matter (cold dark matter (CDM)) which is non-luminous and a large amount of smooth energy (dark ...

    • Charge response of polyethylene terephthalate polymers (PET) to light and heavy nuclei 

      Basu, B.; Dey, S.; Fischer, B.; Maulik, A.; Mazumdar, A.; Raha, Sibaji; Saha, S.; Saha, S.K.; Syam, Debapriyo (PERGAMON-ELSEVIER SCIENCE LTD, 2008-08-01)
      A particular brand of common polymer film has been found to have a high detection threshold value of Z / β, when used as a solid state nuclear track detector to detect energetic ion beams. From the infra-red absorption ...

    • Polyethylene terephthalate polymers at mountain altitude as cosmic ray heavy particle detector 

      Basu, B.; Biswas, S.; Dey, S.; Maulik, A.; Mazumdar, A.; Raha, Sibaji; Saha, S.; Saha, S.K.; Syam, Debapriyo (PERGAMON-ELSEVIER SCIENCE LTD, 2008-08-01)
      We exposed a stack of polyethylene terephthalate (PET) detectors each of thickness I 100 mu m with an area of 21 cm x 30cm along with a separate stack of the standard solid state nuclear track detector (SSNTD) CR-39 ...

    • Determination of the depth of an etch pit through studies of diffraction rings 

      Basu, B.; Dey, S.; Maulik, A.; Raha, Sibaji; Saha, S.; Saha, Swapan K.; Syam, Debapriyo (PERGAMON-ELSEVIER SCIENCE LTD, 2009-04-01)
      A Solid State Nuclear Track Detector (SSNTD) can be used to identify an impinging ion as well as to determine the energy of that ion. The track of the ion is made visible by chemically 'etching' the detector after exposure. ...

    • A study of the gamma-ray flux during the total solar eclipse of 1 August 2008 at Novosibirsk, Russia 

      Nayak, Pranaba K.; Gupta, Sunil K.; Jain, Atul; Mazumdar, Indranil; Raha, Sibaji; Saha, Swapan K.; Bobrov, Aleksandr V.; Osipov, Anton; Shwartz, Boris (ELSEVIER SCIENCE BV, 2010-01-01)
      In the past, there have been reports of the observation of decrease in the flux of secondary cosmic gamma-rays during a total solar eclipse. We have measured the flux of secondary cosmic gamma-rays during the total solar ...

    • Bose Institute : A Historical Perspective,1917-47 

      Siddiqi, Maqsood; Raha, Sibaji (Pearson Longman, 2011)

    • Characterization and Calibration of a SSNTD for Heavy-ion Detection and Strangelet Search in Cosmic Rays 

      Bhowmik, D.; Dey, S.; Maulik, A.; Raha, Sibaji; Saha, S.; Saha, Swapan K.; Syam, Debapriyo (Elsevier, 2011-01-15)
      A commercially available grade of polymer was investigated for its suitability as a solid state nuclear track detector (SSNTD) to look for rare events in cosmic rays at very high mountain altitudes. It was identified to ...