arXiv subjects

Tuomas Multamaki

Publications and source records attributed to Tuomas Multamaki.

24 records · Page 2Linked to original sources

arXiv2000

Q-Ball Collisions in the MSSM

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.

hep-ph↗

arXiv2000

Q-ball collisions in the MSSM: gauge-mediated supersymmetry breaking

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 fusion cross-section has been estimated to be larger than 60% of the geometrical cross-section for large balls.

hep-ph↗

arXiv2000

Q-ball collisions in the MSSM: gravity-mediated supersymmetry breaking

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 after a collision is found to be weakly dependent on the initial charge.

hep-ph↗

arXiv1999

Analytical and numerical properties of Q-balls

Stable non-topological solitons, Q-balls, are studied using analytical and numerical methods. Three different physically interesting potentials that support Q-ball solutions are considered: two typical polynomial potentials and a logarithmic potential inspired by supersymmetry. It is shown that Q-balls in these potentials exhibit different properties in the thick-wall limit where the charge of a Q-ball is typically considerably smaller than in the thin-wall limit. Analytical criteria are derived to check whether stable Q-balls exists in the thick-wall limit for typical potentials. Q-ball charge, energy and profiles are presented for each potential studied. Evaporation rates are calculated in the perfect thin-wall limit and for realistic Q-ball profiles. It is shown that in each case the evaporation rate increases with decreasing charge.

hep-ph↗

arXiv1998

Electroweak Baryogenesis in a Left-Right Supersymmetric Model

The possibility of electroweak baryogenesis is considered within the framework of a left-right supersymmetric model. It is shown that for a range of parameters the large sneutrino VEV required for parity breaking varies at the electroweak phase transition leading to a production of baryons. The resulting baryon to entropy ratio is approximated to be ${n_B\over s}\sim α0.7 \times10^{-8}$, where $α$ is the angle that the phase of sneutrino VEV changes at the electroweak phase transition.

hep-ph↗

arXiv1998

Spontaneous R-Parity Violation and Electroweak Baryogenesis

The possibility of baryogenesis at the electroweak phase transition is considered within the context of a minimal supersymmetric standard model with spontaneous R-parity violation. Provided that at least one of the sneutrino fields acquires a large enough vacuum expectation value, a sufficient baryon asymmetry can be created. Compared to R-parity conserving models the choice of soft supersymmetry breaking parameters is less restricted. The observed baryon asymmetry, n_B/s ~ 10^(-10), can be explained by this scenario and the produced baryon-to-entropy ratio may easily be as high as n_B/s ~ 10^(-9).

hep-ph↗