An Algorithm And Application For Visualization And Analysis Of Scanning Laser Altimeter Data

Ice sheet elevation changes have been measured by repeat airborne laser altimetery in Greenland since 1991. The Airborne Topographic Mapper (ATM) system, which has been mounted in a NASA P-3 aircraft, includes a scanning laser altimeter, INS and differential GPS. During the post-processing the measured data are converted into measurements of ice sheet elevation relative to the Earth ellipsoid (Krabill et aI., 1995). Since laser scanner data sets are composed of a huge amount of points, obtaining the swath contour and locating overlapping areas between different swaths in an efficient way is not a simple task. To make this task more feasible a thinned data set called ICESS has been created from the laser data collected over the Greenland ice sheet (Martin, 1997). Since the surface is reasonably smooth, the laser swath was modeled as a series of planes, each characterized by a center elevation, a north-south slope, and an east-west slope. However, for many applications such as mapping the rough surface of outlet glaciers or surveying urban areas, the original dense laser points are needed. Our major goal is to develop software to access, display, and manipulate the original binary data files. By using a single application the user should be able to determine the overlap between several surveys, compute elevation changes, and create OEMs and contour maps. So far we were mainly focusing on the first part of the job, namely, providing tools for locating the laser swaths and their overlapping areas. In this report we present the algorithm that we recommend for an efficient contour extraction from laser swaths data and the application that was developed for this purpose. The report is organized as follows. First the major objectives of the development of the algorithm are presented and then the algorithm itself is described. The fourth chapter describes the application functionality, and it is followed by a documentation of the software modules and the installation guide

Spin partners of the Zb(10610)Z_b(10610) and Zb(10650)Z_b(10650) revisited

We study the implications of the heavy-quark spin symmetry for the possible spin partners of the exotic states $Z_b(10610)$ and $Z_b(10650)$ in the spectrum of bottomonium. We formulate and solve numerically the coupled-channel equations for the $Z_b$ states that allow for a dynamical generation of these states as hadronic molecules. The force includes short-range contact terms and the one-pion exchange potential, both treated fully nonperturbatively. The strength of the potential at leading order is fixed completely by the pole positions of the $Z_b$ states such that the mass and the most prominent contributions to the width of the isovector heavy-quark spin partner states $W_{bJ}$ with the quantum numbers $J^{++}$ ($J=0,1,2$) come out as predictions. Since the accuracy of the present experimental data does not allow one to fix the pole positions of the $Z_b$'s reliably enough, we also study the pole trajectories of their spin partner states as functions of the $Z_b$ binding energies. It is shown that, once the heavy-quark spin symmetry is broken by means of the physical $B$ and $B^*$ masses, especially the pion tensor force has a significant impact on the location of the partner states clearly demonstrating the need of a coupled-channel treatment of pion dynamics to understand the spin multiplet pattern of hadronic molecules.Comment: 21 pages, 5 figures, 1 tabl

Binding energy of the X(3872)X(3872) at unphysical pion masses

Chiral extrapolation of the $X(3872)$ binding energy is investigated using the modified Weinberg formulation of chiral effective field theory for the $D \bar{D}^*$ scattering. Given its explicit renormalisability, this approach is particularly useful to explore the interplay of the long- and short-range $D \bar{D}^*$ forces in the $X(3872)$ from studying the light-quark (pion) mass dependence of its binding energy. In particular, the parameter-free leading-order calculation shows that the $X$-pole disappears for unphysical large pion masses. On the other hand, without contradicting the naive dimensional analysis, the higher-order pion-mass-dependent contact interaction can change the slope of the binding energy at the physical point yielding the opposite scenario of a stronger bound $X$ at pion masses larger than its physical value. An important role of the pion dynamics and of the 3-body $D\bar{D}\pi$ effects for chiral extrapolations of the $X$-pole is emphasised. The results of the present study should be of practical value for the lattice simulations since they provide a non-trivial connection between lattice points at unphysical pion masses and the physical world.Comment: 24 pages, 4 figure

Effect of Physical Constraints on Spatial Connectivity in Urban Areas

Obstacle effect on proximity, connectivity, and organization of spatial data calls for derivation of measures that enable quantifying their influence. Provision of such measures is valuable for ensuring an aware planning, analysis of obstacle impact on spatial data, and the consequent placement of crossings. This paper proposes quantifying obstacle influence via their impact on connectivity and aggregation of data. As the paper shows, the derived indices enable capturing the actual obstacle effect on spatial data while accommodating datasets with different level of complexity. The information and contribution of these indices are demonstrated and analyzed, and results show how the derived measures reflect changes in spatial data arrangement

Spin partners WbJW_{bJ} from the line shapes of the Zb(10610)Z_b(10610) and Zb(10650)Z_b(10650)

In a recent paper Phys.Rev. D98, 074023 (2018), the most up-to-date experimental data for all measured production and decay channels of the bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$ were analysed in a field-theoretical coupled-channel approach which respects analyticity and unitarity and incorporates both the pion exchange as well as a short-ranged potential nonperturbatively. All parameters of the interaction were fixed directly from data, and pole positions for both $Z_b$ states were determined. In this work we employ the same approach to predict in a parameter-free way the pole positions and the line shapes in the elastic and inelastic channels of the (still to be discovered) spin partners of the $Z_b$ states. They are conventionally referred to as $W_{bJ}$'s with the quantum numbers $J^{PC}=J^{++}$ ($J=0,1,2$). It is demonstrated that the results of our most advanced pionful fit, which gives the best $\chi^2/{\rm d.o.f.}$ for the data in the $Z_b$ channels, are consistent with all $W_{bJ}$ states being above-threshold resonances which manifest themselves as well pronounced hump structures in the line shapes. On the contrary, in the pionless approach, all $W_{bJ}$'s are virtual states which can be seen as enhanced threshold cusps in the inelastic line shapes. Since the two above scenarios provide different imprints on the observables, the role of the one-pion exchange in the $B^{(*)}\bar{B}^{(*)}$ systems can be inferred from the once available experimental data directly.Comment: 24 pages, 12 figure

Quark mass dependence of the X(3872) binding energy

We explore the quark-mass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeev-type three-body equation for the $D\bar{D}\pi$ system in the $J^{PC}=1^{++}$ channel. The $\pi D$ interaction is parametrised via a $D^*$ pole, and a three-body force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a $D\bar{D}^*$ bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the $X$ channel.Comment: LaTeX2e, 14 pages, 5 figures, references updated and extended, to appear in Phys.Lett.

Heavy-quark spin symmetry partners of the X(3872)X(3872) revisited

We revisit the consequences of the heavy-quark spin symmetry for the possible spin partners of the $X(3872)$. We confirm that, if the $X(3872)$ were a $D\bar{D}^*$ molecular state with the quantum numbers $J^{PC}=1^{++}$, then in the strict heavy-quark limit there should exist three more hadronic molecules degenerate with the $X(3872)$, with the quantum numbers $0^{++}$, $1^{+-}$, and $2^{++}$ in line with previous results reported in the literature. We demonstrate that this result is robust with respect to the inclusion of the one-pion exchange interaction between the $D$ mesons. However, this is true only if all relevant partial waves as well as particle channels which are coupled via the pion-exchange potential are taken into account. Otherwise, the heavy-quark symmetry is destroyed even in the heavy-quark limit. Finally, we solve the coupled-channel problem in the $2^{++}$ channel with nonperturbative pions beyond the heavy-quark limit and, contrary to the findings of previous calculations with perturbative pions, find for the spin-2 partner of the $X(3872)$ a significant shift of the mass as well as a width of the order of 50 MeV.Comment: 17 pages, 3 figures, 1 table, version published in Phys.Lett.