1 files changed, 3 insertions, 0 deletions
diff --git a/src/pdg.c b/src/pdg.c
index d6a2161..780fbc8 100644
--- a/src/pdg.c
+++ b/src/pdg.c
@@ -16,6 +16,9 @@ double get_scattering_rms(double x, double p, double beta, double z, double rho)
      * since the radiation length is only discussed in terms of an
      * electromagnetic shower induced by electrons (see Section 33.4.2).
      *
+     * Update: MicroBooNE uses this formula for muons in this paper:
+     * https://arxiv.org/abs/1703.06187.
+     *
      * See Equation 33.15 in
      * http://pdg.lbl.gov/2018/reviews/rpp2018-rev-passage-particles-matter.pdf. */
     if (x == 0.0) return 0.0;