Wednesday, 4 November 2026: 0 new papers, 2 cross-lists and 5 replacements in Accelerator Physics (physics.acc-ph), in arXiv's order, with full abstracts. The same papers as arXiv's own listing, set as a newspaper; every title links to arXiv.
Project 8, a neutrino mass experiment, employs the novel frequency technique of cyclotron radiation emission spectroscopy (CRES) to perform a model independent measurement of neutrino mass via tritium beta decay. Our pioneering experiment will consist of a beamline that dissociates molecular tritium, surface cools atoms through accommodation, evaporatively cools and slows atoms, and traps them in a CRES resonant cavity to advance towards our sensitivity goal of 40 meV/c^2 for our final electron-weighted neutrino mass measurement. We are prototyping an electron cyclotron resonance (ECR) dissociator that uses a tunable 1 kW 2.45 GHz RF generator and electromagnets to ignite a hydrogen plasma in an aluminum resonant cavity. Our ECR source is designed to produce a high atom flux (~10^19 atoms/second) near room temperature. We present the engineering development, gas diagnostics, and spectroscopy data from our hydrogen plasma.
Although plasma-based wakefield acceleration has achieved remarkable success for electrons, efficient positron acceleration remains a long standing challenge, as positrons suffer severe defocusing in the accelerating phases of such structures. Here, we propose a slit plasma wakefield acceleration (SPWA) scheme, in which a relativistic electron beam propagating through a slit channel formed by two parallel plasma slabs excites crossing plasma-electron filamentary structures within the slit, generating intense wakefields tailored to simultaneously provide longitudinal acceleration and transverse focusing for a trailing positron bunch. A theoretical model is developed to characterize the wakefield structure responsible for positron acceleration and focusing. Three-dimensional particle-in-cell simulations validate the model, and demonstrate that the SPWA scheme achieves a positron trapping efficiency of nearly 100%, while maintaining low emittance growth and narrow energy spread for an injected positron beam. These findings establish a new and robust approach to high-efficiency positron acceleration, with promising implications for future compact electron-positron colliders and high-energy positron applications.