Baryon-to-entropy ratio and initial conditions of the Universe

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We show that if the heavy bosons which enter into the grand-unified-theory mechanism for generating nonzero baryon number are created at an earlier stage by the expansion of the Universe and decay sufficiently early ($\mathrm{kT}\ensuremath{\gtrsim}3\ifmmode\times\else\texttimes\fi{}{10}^{15}$ GeV), then the baryon-to-entropy ratio will depend on the degree of anisotropy of the initial expansion. In the case of initially isotropic expansion, the baryon-to-entropy ratio will be roughly 30 times larger than in the standard scenario in which the particles are present initially in a thermal bath.