Add a white paper on line surface jacobian calculation

Core/src/Surfaces/LineSurface.cpp

@@ -227,6 +227,10 @@ Acts::BoundToFreeMatrix Acts::LineSurface::boundToFreeJacobian(
   jacToGlobal(eFreeDir2, eBoundTheta) = -sinTheta;
   jacToGlobal(eFreeQOverP, eBoundQOverP) = 1;
 
+  // For the derivative of global position with bound angles, refer the
+  // following white paper:
+  // https://acts.readthedocs.io/en/latest/white_papers/line-surface-jacobian.html
+
   // the projection of direction onto ref frame normal
   double ipdn = 1. / direction.dot(rframe.col(2));
   // build the cross product of d(D)/d(eBoundPhi) components with y axis

docs/white_papers.toml

@@ -19,9 +19,18 @@ description = "Given the impact parameters $(d_0, z_0, t_0)$ of a track in Perig
 [[white_papers]]
 repository = "https://github.com/beomki-yeo/path-correction-term-from-momentum-variation"
 slug = "correction-for-transport-jacobian"
-pdf_url = "https://github.com/beomki-yeo/path-correction-term-from-momentum-variation/releases/download/v2.0/main.pdf"
+pdf_url = "https://github.com/acts-project/path-correction-term-from-momentum-variation/releases/download/v2.0/main.pdf"
 
 [white_papers.metadata]
 authors = [ "Beomki Yeo",]
 title = "A Correction Term for Transport Jacobian from the Direction Variation"
 description = "In the track extension model of ACTS, the covariance of a track is updated for every surface intersection by applying a jacobian matrix, the composition of the coordinate transformation and free space transport. In the derivation of the transport jacobian, it is necessary to consider the path difference coming from the track displacement, which appears as a direction variation term with respect to the path length. \n\n\nThe motivation of this white paper is that the author failed in finding any reference explaining this clearly. (Please let the author know if anyone finds it) There are bunch of references which calculate this term with an ideal helix model, but it is not very useful with the runge-kutta based track extension model. Therefore, in this note, we are deriving the term thoroughly and demonstrate how it is implemented in the source code."
+[[white_papers]]
+repository = "https://github.com/beomki-yeo/line_surface"
+slug = "line-surface-jacobian"
+pdf_url = "https://github.com/beomki-yeo/line_surface/releases/download/v4.0/main.pdf"
+
+[white_papers.metadata]
+authors = [ "Beomki Yeo",]
+title = "Line Surface Jacobian"
+description = "Line surface used for wire measurements or perigee surface is an unique type of surface where the intersections of a track is not defined on a physical plane. Due to this trait, the underlying mathematics gets quite complicated especially with coordinate transform jacobian whose reference was missing in the source code. (Please let the authors know if anyone finds it). In this white paper, thus we attempt to derive the jacobians for both local-to-global and global-to-local transforms."