Abstract: Ice clouds, particularly cirrus, play a crucial role in Earth's radiative balance, yet remain poorly represented in current climate models. A major source of uncertainty stems from the variability of their microphysical properties, especially the shape of ice crystals. In this paper, we propose a heuristic framework to describe the evolution of four main crystal habits – droxtals, plates, columns, and rosettes – commonly identified in situ observations and widely adopted in radiative transfer simulations. Rather than predicting the exact final morphology of individual crystals, our approach aims to assess the likelihood that, at a given time and under specified thermodynamic conditions, a crystal will most closely correspond to one of these canonical shapes used in cirrus modeling. In this study, we establish the theoretical foundations of this new approach by employing a non-Abelian gauge theory within a field-theoretical framework. Specifically, we impose an SU(2)circle times U(1) symmetry on the fields associated with the probability of habit growth. This symmetry leads to a modified system of coupled Fokker-Planck equations, which capture the stochastic dynamics of ice crystal growth while incorporating phenomenological interactions among different habits. Our framework thus outlines a novel theoretical direction for integrating symmetry principles and field-theoretical tools into the modeling of habit dynamics in ice clouds. At this stage, numerical solutions of the proposed equations have not yet been implemented; developing and validating these with experimental data represents the next step of this research.

Abstract: Hidden-charm pentaquark states with double strangeness, Pcss, have been predicted within the framework of unitary coupled-channel dynamics. In this work, we theoretically investigate the potential to observe these states in the decays Lambda b -> J/psi Xi-K+ and Xi b -> J/psi Xi-pi+. In this framework, these pentaquark configurations couple strongly to the J/psi Xi channel, as well as to other vector-baryon channels with the c<overline>cssn flavor structure, making these decay modes promising for their observation through the corresponding invariant-mass distributions. Our analysis begins with the identification of the dominant weak decay mechanisms, followed by hadronization into meson-baryon channels, connected through flavor symmetry. Final-state interactions are then incorporated to dynamically generate the full amplitude, accounting for the formation of the pentaquark states. We compare our results with recent LHCb measurements of the J/psi Xi- mass distribution and find that, given the predicted pentaquark width of about 10 MeV in this channel, the state is too narrow to be resolved with the current experimental resolution, but it would become visible with significantly improved mass precision.

Abstract: We introduce an innovative graphene-on-silicon photodiode designed for low penetrating radiation. Its standout feature lies in its remarkably-thin dead layer in the entrance window, setting it apart from existing photodetectors. Conventional photodetectors suffer from sensitivity limitations in the low wavelength or energy, respectively, for light or particles, due to their shallow penetration depth. Most conventional photodiodes employ a junction implant which suffers from recombination of low-penetrating photons/particles within the dead layer. Instead, we utilise the nearly transparent properties of single-layer graphene to create a depletion layer that minimises the dead layer. We combine a single junction ring (highly doped n^++ bias ring) with single-layer graphene. The graphene acts as a field plate, extended over the junction ring and covering the entire entrance window (5x5 mm2 active area), while being electrically isolated by an ultrathin, high K dielectric layer. In operation, the photodiode undergoes depletion upon applying a reverse bias as expected, which primarily occurs within the region beneath the field plate. We conducted Transient Current Technique measurements as the best method to assess the charge collection uniformity of the device. Remarkably, the results reveal a consistent total 100% uniformity across the entire detector area. Nevertheless, while the collection time is position-dependent, increasing as the laser incidence point moves farther away from the bias ring, responsivity measurements show excellent response in both the deep ultra violet and vacuum ultra violet regions with > 100% external quantum efficiency at wavelengths below 150 nm.