Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

The neutrino force in neutrino backgrounds: Spin dependence and parity-violating effects

Mitrajyoti Ghosh, Yuval Grossman, Walter Tangarife, Xun-Jie Xu, Bingrong Yu

Abstract

The neutrino force results from the exchange of a pair of neutrinos. A neutrino background can significantly influence this force. In this work, we present a comprehensive calculation of the neutrino force in various neutrino backgrounds with spin dependence taken into account. In particular, we calculate the spin-independent and spin-dependent parity-conserving neutrino forces, in addition to the spin-dependent parity-violating neutrino forces with and without the presence of a neutrino background for both isotropic and anisotropic backgrounds. Compared with the vacuum case, the neutrino background can effectively violate Lorentz invariance and lead to additional parity-violating terms that are not suppressed by the velocity of external particles. We estimate the magnitude of the effect of atomic parity-violation experiments, and it turns out to be well below the current experimental sensitivity.

The neutrino force in neutrino backgrounds: Spin dependence and parity-violating effects

Abstract

The neutrino force results from the exchange of a pair of neutrinos. A neutrino background can significantly influence this force. In this work, we present a comprehensive calculation of the neutrino force in various neutrino backgrounds with spin dependence taken into account. In particular, we calculate the spin-independent and spin-dependent parity-conserving neutrino forces, in addition to the spin-dependent parity-violating neutrino forces with and without the presence of a neutrino background for both isotropic and anisotropic backgrounds. Compared with the vacuum case, the neutrino background can effectively violate Lorentz invariance and lead to additional parity-violating terms that are not suppressed by the velocity of external particles. We estimate the magnitude of the effect of atomic parity-violation experiments, and it turns out to be well below the current experimental sensitivity.
Paper Structure (23 sections, 120 equations, 3 figures, 2 tables)

This paper contains 23 sections, 120 equations, 3 figures, 2 tables.

Table of Contents

  1. Introduction
  2. General formalism
  3. The neutrino force in vacuum
  4. The neutrino force in a general neutrino background
  5. Isotropic backgrounds
  6. Cosmic neutrino background (C$\nu$B)
  7. The Spin-Independent (SI) part
  8. The Spin-Dependent Parity-Conserving (SD-PC) part
  9. The Spin-Dependent Parity-Violating (SD-PV) part
  10. Maxwell-Boltzmann vs Fermi-Dirac distributions
  11. Degenerate neutrino gas
  12. Degenerate neutrino gas
  13. Summary of the results in isotropic backgrounds
  14. Directional neutrino beams
  15. Summary of the results and comparison with known calculations
  16. ...and 8 more sections

Figures (3)

  • Figure 1: $\chi_1\chi_2\to \chi_1\chi_2$ elastic scattering via the exchange of a pair of neutrinos.
  • Figure 2: A sketch of neutrino forces in vacuum (left) and in a neutrino background (right). In vacuum, the long-range force is mediated by exchanging a pair of virtual neutrinos, both of which come from quantum fluctuations. In a background, one of the virtual neutrinos is replaced by an on-shell neutrino from the background.
  • Figure 3: Comparison of the results computed using Maxwell-Boltzmann (MB) and Fermi-Dirac (FD) distributions for the ${\cal J}_b$ and ${\cal J}_c$ factors in Eq. \ref{['eq:VSDbkg']}. The MB and FD curves are produced according to Eqs. \ref{['eq:Jb-MB-massless']}-\ref{['eq:Jc-MB-massless']} and \ref{['eq:Jb-FD']}-\ref{['eq:Jc-FD']}, respectively.