Closed string degeneracies.

For closed string states the left-moving and right-moving excitations are each described like states of open strings with identical values of . The value of for the closed string state is four times that value.

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How come?

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Equation (14.78):

Mass M is two times that value ( or ). So is four times.

— Me@2015.07.14 12:47 PM

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Not necessarily so.

— Me@2015.07.16 08:14 AM

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Instead, it is just due to this definition.

— Me@2015.07.30 09:19 AM

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p.322 “In the closed string theory the value of the mass-squared is given by…”

Equation (14.78) is actually a definition of the mass-squared of a closed string state.

Also, consider

p.322 “As befits closed strings there is also the level-matching condition on the states. This condition guarantees that the left and right sectors give identical contributions to the mass-squared: .”

Then

— Me@2018.03.02 11:05 AM

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2018.03.02 Friday (c) All rights reserved by ACHK