Title: Extended Higgs models and a transition to exact susy
Abstract: String landscape ideas and the observation of a positive vacuum energy in the current universe suggest that there could be a future transition to an exactly supersymmetric world. Atomic and molecular binding in this susy background probably require that electroweak symmetry breaking survives the transition. Among several susy higgs models that have been discussed, one stands out in this regard. Thus, the higgs structure that is revealed at the LHC could have strong consequences for the type of bulk matter that may arise in a future susy universe. PACS. 12.60.Fr Extensions of Higgs Sector – 12.60.Jv Supersymmetric Models The observations of a small but positive vacuum energy in our universe plus the strong indications that, in its early moments, the universe made transitions from states of much higher vacuum energy, raise the question of whether there are further transitions to be expected within our horizon. If so, it is natural to ask what properties this future universe might have. We seem to be living in a bubble that formed some 13.7 billion years ago and that, after passing through many meta-stable states in a brief inflationary era, transitioned to our current calm umiverse which is, nonetheless, still inflating with a vacuum energy density measured to be ǫnow = 3.560GeV/m 3 = (.0023eV ) . (1) This is some 124 orders of magnitude less than the natural value, M Planck that might have been expected for this quantity but it is known [1] that arriving in such a calm universe was a prerequisite for the evolution of advanced life forms. From a physics point of view it is, however, necessary to ask what circumstances might have made this early history of our universe not extremely improbable. This seems to lead inevitably to speculation about possible regions of the universe outside of causal contact with us. For example, the scenario of eternal inflation [2] proposes that the universe is infinite in spatial and temporal extent and that, consequently, however low the probability of life is per unit of space-time volume, there are infinite numbers of civilizations in spacetime that are similar to ours. This picture requires that there is an equilibrium established in the “multiverse” and that the probability of “jumping up” to a state of higher vacuum energy is in statistical balance with that of “jumping down”. It is also thought a Talk presented at Susy07, Karlsruhe Germany by many in this school that there are infinitely many possible states of the universe that are massively antiDeSitter, i.e. possessing enormously negative vacuum energy density ǫ. Such states would collapse in a big crunch on a time scale of 1/ √ 24πGN |ǫ|. The probability of a transition to such a deeply negative vacuum energy should also be quite high raising the question of why our current universe has persisted for its multibillion year lifetime. Furthermore, naive physical intuition suggests that transitioning to a state of lower energy density should be vastly more probable than jumping up and it would seem that additional theoretical analysis would need to be done in this picture to establish a result preventing the universe everywhere from evolving inevitably to the lowest possible vacuum energy. In any case, in the absence of experimental confirmation, one is free to ask whether other possibilities exist. We study an alternate scenario in which the universe has a supersymmetric (susy) gound state of exactly zero vacuum energy. Examples of such universes are provided by the five original superstring theories but we prefer to think in terms of a simple supersymmetric extension of the standard model. In this model the visible universe should eventually make a transition to the susy ground state. One could envision an inhomogeneous universe where, outside of our horizon, shells of higher vacuum energy from the inflationary era are inflating rapidly but without sufficient matter density to spawn galaxies. Note that in the standard false vacuum decay theory [3], vacuum energy goes into the bubble wall and not into creating matter. Outgoing shells may be unlikely to collide sufficiently to create significant matter. Some attention has been given to the possible properties of a future susy universe [4,5]. The primary feature of such a universe is a weakening of the Pauli Principle due to the degeneracy of fermions and bosons. Susy atoms, if they exist, would have entirely s-wave ground states. As in our universe, quantum mechanics predicts that all binding energies are proportional to the electron (or common electron/selectron) mass. The mean radii of susy atoms would be inversely proportional to this mass. Thus, unless electroweak symmetry breaking (EWSB) survives the transition to the future susy universe providing masses, no electromagnetic bound states could be expected. The time scale [4] for the transition to take place is governed by the behavior of the cube of the cosmological scale factor
Publication Year: 2007
Publication Date: 2007-10-15
Language: en
Type: article
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