February 28, 2001
Excited Q-balls are studied by numerical simulations in the Minimal Supersymmetric Standard Model with supersymmetry broken by a gravity mediated mechanism. It is found that there is a suppression factor of $\cO(10^{-2})$ in the rate at which a Q-ball can emit their excess energy compared to the rate set by the dynamical scale of the field, $m$. Furthermore, it is noted that a Q-ball can withstand a large amount of excess energy without losing a significant amount of its charge. The cosmological importance of these properties are considered for Q-balls in the thermal bath of the early universe.
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March 28, 2000
Collisions of non-topological solitons, Q-balls, are studied in a typical potential in the Minimal Supersymmetric Standard Model where supersymmetry has been broken by a gravitationally coupled hidden sector. Q-ball collisions are studied numerically on a two dimensional lattice for a range of Q-ball charges. Total cross-sections, as well as cross-sections for fusion and charge-exchange are calculated. The average percentage increase in charge carried by the largest Q-ball af...
July 10, 1997
Q-balls are generically present in models with softly broken low-energy supersymmetry. We discuss the properties of these non-topological solitons, which can precipitate a new kind of first-order phase transition in the early Universe and have other important implications for cosmology and experiment.
May 17, 2000
Collisions of non-topological solitons, Q-balls, are considered in the Minimal Supersymmetric Standard Model where supersymmetry has been broken at a low energy scale via a gauge mediated mechanism. Q-ball collisions are studied numerically on a two dimensional lattice for a range of Q-ball charges. Total cross-sections, as well as fusion and geometrical cross-sections are calculated. The total and geometrical cross-sections appear to converge with increasing charge. The fusi...
December 21, 2007
We study numerically a class of non-topological solitons, the Q-balls, arising in supersymmetric extension of the Standard Model with low-energy, gauge-mediated symmetry breaking. % Taking into account the exact form of the supersymmetric potential giving rise to Q-balls, we find that there is a lower limit on the value of the charge $Q$ in order to make them classically stable: $Q \gtrsim 5 \times 10^2 Q_{\rm cr}$, where $Q_{\rm cr}$ is constant depending on the parameters d...
October 18, 2000
Collisions of non-topological solitons, Q-balls, are studied in the Minimal Supersymmetric Standard Model in two different cases: where supersymmetry has been broken by a gravitationally coupled hidden sector and by a gauge mediated mechanism at a lower energy scale. Q-ball collisions are studied numerically on a two dimensional lattice for a range of Q-ball charges. Total cross-sections as well as cross-sections for fusion and charge exchange are calculated.
June 13, 2000
We obtain a new type of a stable Q ball in the context of gauge-mediated supersymmetry breaking in minimal supersymmetric standard model. It is so-called gravity-mediation type of Q ball, but stable against the decay into nucleons, since the energy per unit charge is equal to gravitino mass m_{3/2}, which can be smaller than nucleon mass in the gauge-mediation mechanism. We consider the cosmological consequences in this new Q-ball scenario, and find that this new type of the ...
November 28, 1997
We show that Q-balls naturally exist in the Minimal Supersymmetric Standard Model (MSSM) with soft SUSY breaking terms of the minimal N=1 SUGRA type. These are associated with the F- and D-flat directions of the scalar potential once radiative corrections are taken into account. We consider two distinct cases, corresponding to the "H_u L" (slepton) direction with L-balls and the "udd" and "uude" (squark) directions with B-balls. The L-ball always has a small charge, typically...
July 8, 1998
In the MSSM with gravity mediated supersymmetry breaking, there may exist unstable but long-lived solitons carrying large baryonic charge, or B-balls. These decay well afterthe electroweak phase transition, giving rise to B-ball baryogenesis. Being made of squarks, B-ball decays produce also LSPs and hence can be the source for all cold dark matter.
October 5, 2009
We revisit the new-type of the Q ball (the gravity-mediation type of the Q ball in the gauge-mediation), in order to clarify its properties and correct some misunderstandings found in the recent literature. In addition, we investigate the feature of the other kind of the hybrid-type of the Q ball, which was considered in the context of the Q-ball capture by the neutron star.
February 28, 2000
We study the formation of Q-balls which are made of flat directions that appear in the supersymmetric extension of the standard model in the context of gravity-mediated supersymmetry breaking. The full non-linear calculations for the dynamics of the complex scalar field are made. Since the scalar potential in this model is flatter than \phi^2, we have found that fluctuations develop and go non-linear to form non-topological solitons, Q-balls. The size of a Q-ball is determine...