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Starting from compete UV description of QCD (in the confined phase), if we integrate out the quarks and Glueballs, in principle, we will get an effective theory of strings (QCD flux tube and not fundamental strings). This effective theory clearly exists in $D=4$. The simplest theoretical model to study such an effective theory is to consider a infinitely long string (arXiv:1302.6257), such solutions exit and are stable in known theories e.g. pure Yang-Mills in any $D$.

In the presence of such a long string the theory breaks $SO(D-1,1)$ spacetime symmetry to $SO(1,1) \times SO(D-2)$. The Nambu-Goldstone modes from this symmetry breaking are the only physical degrees of freedom on the worldsheet of this string.

In the light cone gauge, away from critical dimensions ($D=26$) the spectrum does not obey Lorentz symmetry. The Weyl anomaly we get, in the covariant formulation appears as the Lorentz anomaly in the light cone gauge.

It is claimed (e.g. in arXiv:1603.06969 section 2.1) in the static gauge $(X^0 = \tau, X^1 = \sigma)$ where $(\tau,\sigma)$ are the worldsheet coordinates. The theory is unitary and there is no anomaly. Intuitively any gauge choice should reflect the anomaly in some form. So,

Why is effective string theory without any anomaly, in the static gauge, away from critical dimensions?

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  • $\begingroup$ "Starting from compete UV description of QCD (in the confined phase), if we integrate out the quarks and Glueballs, in principle, we will get an effective theory of strings" Do you have a source for this? What about baryons? $\endgroup$ Commented Oct 8, 2023 at 7:31
  • $\begingroup$ I am thinking of integrating out all the massive degrees of freedom. This calculation of course has not been actually done as far I know, but it is the an EFT argument. Look at this (journals.aps.org/prl/abstract/10.1103/PhysRevLett.67.1681) for example. My question is about the anomaly in the formulation of effective theory of long string, so it should not matter which UV theory I start with or if I can actually drive the EFT starting from the UV theory, as long as I have a string like excitation in the IR. $\endgroup$ Commented Oct 9, 2023 at 6:37
  • $\begingroup$ Do the comments around 5.3 and 5.4 in Aharony Komargodski 2013 answer your question? (specifically about cancelling the conformal anomaly) $\endgroup$ Commented Oct 9, 2023 at 14:28
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    $\begingroup$ This is what I was looking for, thanx a lot. $\endgroup$ Commented Oct 16, 2023 at 12:21

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