63,878 research outputs found
Comment on Vacuum Stability and Electroweak Baryogenesis in the MSSM with Light Stops
We show that, for all values of and the light right-handed stop
mass for which the electroweak phase transition is strong enough to avoid
washout following electroweak baryogenesis, the electroweak vacuum is stable
over the lifetime of the observed Universe.
Cosmological stability of the electroweak vacuum is violated only if the
light right-handed stop is lighter than 100-115GeV.Comment: LaTex, 11 pages, no figures. Additions to text and reference
Anthropically Selected Baryon Number and Isocurvature Constraints
The similarity of the observed baryon and dark matter densities suggests that
they are physically related, either via a particle physics mechanism or
anthropic selection. A pre-requisite for anthropic selection is the generation
of superhorizon-sized domains of different Omega_{B}/Omega_{DM}. Here we
consider generation of domains of different baryon density via random
variations of the phase or magnitude of a complex field Phi during inflation.
Baryon isocurvature perturbations are a natural consequence of any such
mechanism. We derive baryon isocurvature bounds on the expansion rate during
inflation H_{I} and on the mass parameter mu which breaks the global U(1)
symmetry of the Phi potential. We show that when mu < H_{I} (as expected in
SUSY models) the baryon isocurvature constraints can be satisfied only if H_{I}
is unusually small, H_{I} < 10^{7} GeV, or if non-renormalizable
Planck-suppressed corrections to the Phi potential are excluded to a high
order. Alternatively, an unsuppressed Phi potential is possible if mu is
sufficiently large, mu > 10^{16} GeV. We show that the baryon isocurvature
constraints can be naturally satisfied in Affleck-Dine baryogenesis, as a
result of the high-order suppression of non-renormalizable terms along MSSM
flat directions.Comment: 8 pages, 1 eps figure, LaTeX. Minor typo correcte
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Getting By With The Advice Of Their Friends: Ceos' Advice Networks And Firms' Strategic Responses To Poor Performance
This paper theorizes that relatively poor firm performance can prompt chief executive officers (CEOs) to seek more advice from executives of other firms who are their friends or similar to them and less advice from acquaintances or dissimilar others and suggests how and why this pattern of advice seeking could reduce firms' propensity to change corporate strategy in response to poor performance. We test our hypotheses with large-sample survey data on the identities of CEOs' advice contacts and archival data on firm performance and corporate strategy. The results confirm our hypotheses and show that executives' social network ties can influence firms' responses to economic adversity, in particular by inhibiting strategic change in response to relatively poor firm performance. Additional findings indicate that CEOs' advice seeking in response to low performance may ultimately have negative consequences for subsequent performance, suggesting how CEOs' social network ties could play an indirect role in organizational decline and downward spirals in firm performance.Business Administratio
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