Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Charge distribution of the gauge-mediation type Q ball

Shinta Kasuya, Masahiro Kawasaki

TL;DR

The paper investigates the formation of gauge-mediation type Q balls in a logarithmic square potential using 3D lattice simulations, revealing a broad charge distribution rather than a single dominant charge. By analyzing the resulting distribution, it demonstrates that both stable and unstable Q balls can coexist, which alters standard DM and baryogenesis scenarios and imposes new cosmological constraints. The study finds that stable B-balls can serve as DM for a wide range of $M_F$, while single-flat-direction baryogenesis is unlikely; large L-balls may also constitute DM for certain $M_F$ and $\phi_0$ values, though their decays typically fail to explain the 511 keV excess. Overall, the broad charge distribution profoundly impacts the cosmological and astrophysical roles of gauge-mediation Q balls and informs constraints on SUSY-breaking scales.

Abstract

We numerically study the formation of the gauge-mediation type Q balls in the logarithmic square potential on three-dimensional lattices. We obtain the broad charge distribution of the Q ball of this type for the first time. The charge of the Q ball at the peak of the distribution is smaller than what we estimated as the average of the largest tens of the Q balls in the logarithmic potential for the same initial amplitude of the field at the onset of its oscillation. We also discuss some impacts of the broad distribution on cosmology and astrophysics. In the B ball (Q being the baryon number) case, the broad distribution would lead to the coexistence of both stable and unstable B balls. We find that stable B balls can account for the dark matter of the universe without affecting successful big bang nucleosynthesis by the decay of the unstable B balls, but the baryon number of the universe cannot be explained by them. On the other hand, the large L balls (Q being the lepton number) would be the dark matter as well while avoiding the constraints on the X and/or gamma rays from the decay of the smaller L balls.

Charge distribution of the gauge-mediation type Q ball

TL;DR

The paper investigates the formation of gauge-mediation type Q balls in a logarithmic square potential using 3D lattice simulations, revealing a broad charge distribution rather than a single dominant charge. By analyzing the resulting distribution, it demonstrates that both stable and unstable Q balls can coexist, which alters standard DM and baryogenesis scenarios and imposes new cosmological constraints. The study finds that stable B-balls can serve as DM for a wide range of , while single-flat-direction baryogenesis is unlikely; large L-balls may also constitute DM for certain and values, though their decays typically fail to explain the 511 keV excess. Overall, the broad charge distribution profoundly impacts the cosmological and astrophysical roles of gauge-mediation Q balls and informs constraints on SUSY-breaking scales.

Abstract

We numerically study the formation of the gauge-mediation type Q balls in the logarithmic square potential on three-dimensional lattices. We obtain the broad charge distribution of the Q ball of this type for the first time. The charge of the Q ball at the peak of the distribution is smaller than what we estimated as the average of the largest tens of the Q balls in the logarithmic potential for the same initial amplitude of the field at the onset of its oscillation. We also discuss some impacts of the broad distribution on cosmology and astrophysics. In the B ball (Q being the baryon number) case, the broad distribution would lead to the coexistence of both stable and unstable B balls. We find that stable B balls can account for the dark matter of the universe without affecting successful big bang nucleosynthesis by the decay of the unstable B balls, but the baryon number of the universe cannot be explained by them. On the other hand, the large L balls (Q being the lepton number) would be the dark matter as well while avoiding the constraints on the X and/or gamma rays from the decay of the smaller L balls.
Paper Structure (12 sections, 55 equations, 11 figures)

This paper contains 12 sections, 55 equations, 11 figures.

Table of Contents

  1. Introduction
  2. Gauge-mediation type Q balls
  3. Q-ball formation
  4. Cosmological and astrophysical consequences of the broad charge distribution
  5. B balls
  6. L balls
  7. $\tilde{\nu}_\mu\tilde{e}^-\tilde{e}^+$ direction with $\phi_0=\phi_{\rm max}$
  8. $\tilde{\nu}_\tau\tilde{\mu}^-\tilde{e}^+$ direction with $\phi_0=\phi_{\rm max}$
  9. $\tilde{\nu}_\tau\tilde{\mu}^-\tilde{e}^+$ direction with smaller $\phi_0$
  10. Conclusion
  11. Rough constraint on $\Omega_{e^+}/\Omega_{\rm DM}$
  12. Value of $\xi$

Figures (11)

  • Figure 1: Evolution of the homogeneous modes $\varphi^2=\varphi_R^2 + \varphi_I^2$ and the fluctuations $\delta\varphi^2=\delta\varphi_R^2+\delta\varphi_I^2$ for various initial amplitudes.
  • Figure 2: Formed Q balls in three-dimensional lattices with $N=1000$ and $\Delta\xi=0.5$ at $a/a_{\rm initi}\simeq 17$ for $\varphi_0=5\times 10^3$.
  • Figure 3: Normalized charge distribution of the Q balls. Thick solid (green) line shows the fitting formula, whose peak is denoted in vertical thin solid (black) line at $\tilde{Q}=3\times 10^{-5}$.
  • Figure 4: Peak charge of the Q balls. Also shown is the relation (\ref{['Qphi2']}) in blue solid line.
  • Figure 5: Sketches of monochromatic and broad distribution of the B balls.
  • ...and 6 more figures