Collisions of low-energy antiprotons with molecular hydrogen: ionization, excitation and stopping power

A time-dependent coupled-channel approach was used to calculate ionization, excitation, and energy-loss cross sections as well as energy spectra for antiproton and proton collisions with molecular hydrogen for impact energies 8 keV < E < 4000 keV.Comment: 4 pages, 4 figures, conference LEAP0

Lifetimes of C-60(2-) and C-70(2-) dianions in a storage ring

C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb barrier, mainly from thermally populated triplet states about 120 meV above a singlet ground state. At times longer than about 100 ms, the absorption of blackbody radiation plays an important role for the decay of initially cold ions. The tunneling rates obtained from the modeling, combined with WKB estimates of the barrier penetration, give a ground-state energy 200 +/- 30 meV above the energy of the monoanion plus a free electron and a ground-state lifetime of the order of 20 s. (c) 2006 American Institute of Physics

Close-coupling approach to antiproton-impact ionisation of H2 with analytical spherical averaging

Integrated cross section for single ionisation of molecular hydrogen by antiproton impact has been calculated in a wide range of impact energies from 1 keV up to 2 MeV using a close-coupling approach. For the first time all possible orientations of the molecular target have been accounted for using an ab initio analytical spherical averaging technique. Obtained results are in good agreement with experiment

Fully quantum-mechanical treatment of proton-hydrogen scattering

© Published under licence by IOP Publishing Ltd. A fully quantum-mechanical convergent close-coupling approach to proton collisions with atomic hydrogen has been developed. Cross sections for target ionisation and electron capture by the projectile have been calculated in the energy range from 20 keV to 1 MeV. Calculated electron capture cross sections are in good agreement with the experiment, however for ionisation discrepancies between theory and experiment at intermediate energies still remain

Ionization of hydrogen and hydrogenic ions by antiprotons

Presented here is a description of the ionization of hydrogen and hydrogenic ions by antiproton-impact, based on very large scale numerical solutions of the time-dependent Schr\"odinger equation in three spatial dimensions and on analysis of the topology of the electronic eigenenergy surfaces in the plane of complex internuclear distance. Comparison is made with other theories and very recent measurements.Comment: RevTex document, 11 pages, 4 Postscript figures are available from the authors, in press Phys. Rev. Let

coreNASH: Multi-stakeholder Consensus on Core Outcomes for Decision Making About Nonalcoholic Steatohepatitis Treatment

The increasing prevalence and burden of nonalcoholic steatohepatitis (NASH) has spurred the development of new treatments and a need to consider outcomes used for NASH treatment decision making. Development of a NASH core outcome set (COS) can help prioritize outcomes of highest importance by incorporating the perspectives from a variety of decision makers. coreNASH was an initiative to develop a COS for NASH using a modified Delphi consensus process with a multi-stakeholder voting panel. A candidate outcome list was created based on a literature review and key informant interviews. The candidate outcome list was then condensed and prioritized through three rounds of online voting and through discussion at an in-person meeting. Outcomes were retained or eliminated based on predetermined consensus criteria, which included special weighting of patients’ opinions in the first two voting rounds. The coreNASH Delphi panel included 53 participants (7 patients, 10 clinicians and researchers, 7 health technology assessors, 22 industry representatives, 2 regulators, and 5 payers) who considered outcomes for two NASH-related COS: one for NASH without cirrhosis (F2-F3) and one for NASH with cirrhosis (F4). The initial candidate outcome list for both disease stages included 86 outcomes. The panel agreed on including two core outcomes for NASH without cirrhosis and nine core outcomes for NASH with cirrhosis in the COS. Conclusion: A consensus-based COS has been developed that can be used across the life cycle of NASH treatments. Outcomes included can contribute to decision making for regulatory, market access, and on-market decision making. Including the coreNASH COS in clinical development programs will facilitate improved comparisons and help decision makers assess the value of new products