Equation 1 · Part 2 · Nucleosynthesis Is Descent With Modification

Symbol tau_n

\tau_{\beta^-} \ll \tau_n \qquad \text{(s-process)}

\tau_n

What this part means

the mean waiting time between successive neutron captures on a given nucleus.

Its job in the formula

ta $u_n$ is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Full expressionSymbol tau_nArticle meaning

Where the article explains it

where $\tau_n$ is the mean waiting time between successive neutron captures on a given nucleus and $\tau_{\beta^-}$ is that nucleus’s beta-decay half-life.

The passage around this formula

…so each newly captured neutron has time to beta-decay, if it is going to, before the next one arrives. That condition can be written as a simple inequality between two competing timescales: $\tau_{\beta^-} \ll \tau_n \qquad \text{(s-process)}$ . where $\tau_n$ is the mean waiting time between successive neutron captures on a given nucleus and $\tau_{\beta^-}$ is that nucleus’s beta-decay half-life. Because the s-process obeys this inequality, its reaction path never strays far from the valley of nuclear stability: a nucleus captures a neutron, and…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the surrounding passage

[7] The History of the S Process and Its Present State ↗

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