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The string scale and the Planck scale

Rainer Dick
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Abstract

A particle spectrum below the string scale in accordance with predictions from heterotic string theory yields a Planck mass $m_{Pl}=(8πG_N)^{-1/2}$ which exceeds the string scale by a factor $\simeq 61.9$. A Planck mass $m_{Pl}=2.43\times 10^{18}$ GeV then corresponds to a string scale $m_s=3.9\times 10^{16}$ GeV. Such a low value for the string scale in turn implies that the relative strength of graviton and vector exchange in the string/M-theory phase exceeds the corresponding ratio in the low energy field theory.

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Rainer Dick. 1997-07-23. The string scale and the Planck scale. https://arxiv.org/abs/hep-th/9707195

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