• Supernova neutrinos: Flavor conversion independent of their mass

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/039/04/0049

    • Keywords

       

      Supernovae; dense neutrinos; flavor conversion.

    • Abstract

       

      In extremely dense neutrino environments like in supernova core, the neutrino-neutrino refraction may give rise to self-induced flavor conversion. These neutrino flavor oscillations are well understood from the idea of the exponentially growing modes of the interacting oscillators in the flavor space. Until recently, the growth rates of these modes were found to be of the order of the vacuum oscillation frequency $\Delta m^2/2E$ $[O(1 {\rm km}^{−1})]$ and were considered slow growing. However, in the last couple of years it was found that if the system was allowed to have different zenith-angle distributions for the emitted $\nu_e$ and $\bar{\nu}_e$ beams then the fastest growing modes of the interacting oscillators grew at the order of $\mu =\sqrt{2G_{\rm F}n_ν}$ , a typical $\nu–\nu$ interaction energy $[O(10^5 {\rm km}^{−1})]$. Thus the growth rates are very large in comparison to the so-called ‘slow oscillations’ and canresult in neutrino flavor conversion on a much faster scale. In fact, the point that the growth rates are no longer dependent on the vacuum oscillation frequency $\Delta m^2/2E$, makes these ‘fast flavor conversions’ independentof $\Delta m^2$ (thus mass) and energy. This is a surprising result as neutrino flavor conversions are considered to be the ultimate proof of massive neutrinos. However, the importance of this effect in the realistic astrophysical scenarios still remains to be understood.

    • Author Affiliations

       

      S. CHAKRABORTY1

      1. Indian Institute of Technology Guwahati, Guwahati 781 039, India.
    • Dates

       
  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2022-2023 Indian Academy of Sciences, Bengaluru.