Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Cosmological consequences of dilatons in the electroweak model
AU - McDonald, John
PY - 1992/1/2
Y1 - 1992/1/2
N2 - We consider the cosmological evolution of an electroweak model with a Jordan-Brans-Dicke dilaton, as would result from spontaneously breaking scale-invariance in a complete theory. For the case where the Friedman-Robertson-Walker (FRW) metric is introduced in the Einstein frame, it is shown that the phase transition is first-order, in agreement with previous treatments of this question. It is however argued that the treatment given here is more physically correct than previous treatments. It is also shown that at the electroweak phase transition, which occurs at the temperature of chiral symmetry breaking, most of the vacuum energy goes into oscillations of the dilaton field, with essentially no reheating or increase in entropy. As a result, the universe becomes effectively matter dominated before nucleosynthesis, ruling out the model. The only way to avoid this problem is to have scale-invariance broken at less than O(10(7)) GeV. For the case where the FRW metric is introduced in the Jordan frame, the electroweak phase transition is of second-order as for the minimal standard model. The question of the energy density in dilatons is dependent upon the assumed form of the dilaton potential.
AB - We consider the cosmological evolution of an electroweak model with a Jordan-Brans-Dicke dilaton, as would result from spontaneously breaking scale-invariance in a complete theory. For the case where the Friedman-Robertson-Walker (FRW) metric is introduced in the Einstein frame, it is shown that the phase transition is first-order, in agreement with previous treatments of this question. It is however argued that the treatment given here is more physically correct than previous treatments. It is also shown that at the electroweak phase transition, which occurs at the temperature of chiral symmetry breaking, most of the vacuum energy goes into oscillations of the dilaton field, with essentially no reheating or increase in entropy. As a result, the universe becomes effectively matter dominated before nucleosynthesis, ruling out the model. The only way to avoid this problem is to have scale-invariance broken at less than O(10(7)) GeV. For the case where the FRW metric is introduced in the Jordan frame, the electroweak phase transition is of second-order as for the minimal standard model. The question of the energy density in dilatons is dependent upon the assumed form of the dilaton potential.
KW - INFLATION
U2 - 10.1016/0370-2693(92)90306-O
DO - 10.1016/0370-2693(92)90306-O
M3 - Journal article
VL - 274
SP - 72
EP - 78
JO - Physics Letters B
JF - Physics Letters B
SN - 0370-2693
IS - 1
ER -