title: WIMP detection and slow ion dynamics in carbon nanotube arrays.
abstract: Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs ([Formula: see text] GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with respect to CNT directions. New constraints are obtained on how to devise the CNT arrays to maximize the target channeling efficiency.
authors.affiliation: INFN Sezione di Roma, Piazzale A. Moro 2, 00185 Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cavoto
authors.affiliation: Dipartimento SBAI, Sapienza Università di Roma, Via A. Scarpa 16, 00161 Rome, Italy.
authors.forename: E N M
authors.initials: EN
authors.lastname: Cirillo
authors.affiliation: Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Cocina
authors.affiliation: Dipartimento di Fisica and INFN, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Rome, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Ferretti
authors.affiliation: Dipartimento di Fisica and INFN, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Rome, Italy ; Theory Division, CERN, 1211 Geneva, Switzerland.
authors.forename: A D
authors.initials: AD
authors.lastname: Polosa