CTEQ Handbook Version 1.0 Errata

Here we only record substantive corrections, but all corrections are
welcome.  Send to scalise@phys.psu.edu.


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Equations (4.49) to (4.50) should read
\begin{eqnarray}
   P_{11}^{{\rm hel}}   \equiv  P_{22}^{{\rm hel}}  = 0,
\\
   P_{12}^{{\rm hel}}   \equiv  -P_{21}^{{\rm hel}}  = -i,
\nonumber \\
   P_{n,jj'}^{{\rm lin}} \equiv 2 n_{j}n_{j'} - \delta _{jj'}.
\end{eqnarray}
The correction is to the sign of $P^{\rm hel}$.  This can be checked by
observing that the transverse parts of the polarization vectors for
gluons with helicity $\lambda$ are
\begin{displaymath}
   \left( \epsilon^1(\lambda),\epsilon^2(\lambda) \right) =
   - \frac{1}{\sqrt 2}\ \left( \lambda,i \right)
\end{displaymath}
(up to an overall phase), and that the matrix $P_{jj'}^{\rm hel}$
should be
\begin{displaymath}
   P^{jj'} = \sum_{\lambda = \pm 1}
             \lambda\, \epsilon^j(\lambda) \epsilon^{j'}(\lambda)^*
\end{displaymath}
We need to be careful that this is the matrix and not its transpose. 
The $\epsilon^*$ multiplies the gluon destruction operator.

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Equation 6.26 should read:

[(1+x^2)/(1-x)]_+ = P_{qq}^(1)(x) = (1+x^2)/[1-x]_+  + 3/2 \delta(1-x)

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