Exploration of Elastic Scattering Rates for Supersymmetric Dark Matter

We explore the possible cross sections for the elastic scattering of neutralinos chi on nucleons p,n in the minimal supersymmetric extension of the standard model (MSSM). Universality of the soft supersymmetry-breaking scalar masses for the Higgs multiplets is not assumed, but the MSSM parameters are nevertheless required to lead consistently to an electroweak vacuum. We explore systematically the region of MSSM parameter space where LEP and other accelerator constraints are respected, and the relic neutralino density lies in the range 0.1 < Omega_chi h^2 < 0.3 preferred by cosmology. We also discuss models with Omega_chi h^2 < 0.1, in which case we scale the density of supersymmetric dark matter in our galactic halo by Omega_chi h^2 / 0.1, allowing for the possible existence of some complementary form of cold dark matter. We find values of the cross sections that are considerably lower than the present experimental sensitivities. At low neutralino masses, m_chi < 100 GeV, the cross sections may be somewhat higher than in the constrained MSSM with universal soft Higgs masses, though they are generally lower. In the case of large m_chi, the cross sections we find may be considerably larger than in the constrained model, but still well below the present experimental sensitivity.Comment: 25 pages LaTeX, 7 eps figure

Magneto-optical determination of the electron-solid phase-boundary

We have obtained a two-dimensional electron-solid phase diagram in the extreme magnetic quantum limit by studying the temperature dependence of the radiative recombination of electrons in a GaAs/AlxGa1-xAs heterojunction with holes bound to a delta-layer, 250 A away in the GaAs, of Be acceptors. The low-energy shoulder to the luminescence line, indicating the presence of the electron solid, is seen to disappear at a filling-factor-dependent critical temperature. We observe no shoulder above a filling factor of 0.25, and the critical temperature falls to below 0.4 K at filling factors 1/5 and 1/7

Exclusive electroproduction revisited: treating kinematical effects

Generalized parton distributions of the nucleon are accessed via exclusive leptoproduction of the real photon. While earlier analytical considerations of phenomenological observables were restricted to twist-three accuracy, i.e., taking into account only terms suppressed by a single power of the hard scale, in the present study we revisit this differential cross section within the helicity formalism and restore power-suppressed effects stemming from the process kinematics exactly. We restrict ourselves to the phenomenologically important case of lepton scattering off a longitudinally polarized nucleon, where the photon flips its helicity at most by one unit.Comment: 22 pages, 1 figur

Einstein's Real "Biggest Blunder"

Albert Einstein's real "biggest blunder" was not the 1917 introduction into his gravitational field equations of a cosmological constant term \Lambda, rather was his failure in 1916 to distinguish between the entirely different concepts of active gravitational mass and passive gravitational mass. Had he made the distinction, and followed David Hilbert's lead in deriving field equations from a variational principle, he might have discovered a true (not a cut and paste) Einstein-Rosen bridge and a cosmological model that would have allowed him to predict, long before such phenomena were imagined by others, inflation, a big bounce (not a big bang), an accelerating expansion of the universe, dark matter, and the existence of cosmic voids, walls, filaments, and nodes.Comment: 4 pages, LaTeX, 11 references, Honorable Mention in 2012 Gravity Research Foundation Essay Award

Bose-Einstein Final State Symmetrization for Event Generators of Heavy Ion Collisions

We discuss algorithms which allow to calculate identical two-particle correlations from numerical simulations of relativistic heavy ion collisions. A toy model is used to illustrate their properties.Comment: Talk given at CRIS'98 (Catania, June 8-12, 1998), to appear in "CRIS'98: Measuring the size of things in the Universe: HBT interferometry and heavy ion physics", (S. Costa et al., eds.), World Scientific, Singapore, 1998. (10 pages Latex, 1 eps-figure, extended version of conference proceedings, Fig1 a,b added and corresponding discussion enlarged

Bose-Einstein Correlations in a Space-Time Approach to e+ e- Annihilation into Hadrons

A new treatment of Bose-Einstein correlations is incorporated in a space-time parton-shower model for e+ e- annihilation into hadrons. Two alternative afterburners are discussed, and we use a simple calculable model to demonstrate that they reproduce successfully the size of the hadron emission region. One of the afterburners is used to calculate two-pion correlations in e+ e- -> Z^0 -> hadrons and e+ e- -> W+ W- -> hadrons. Results are shown with and without resonance decays, for correlations along and transverse to the thrust jet axis in these two classes of events.Comment: 30 pages, Latex, 8 figure

Exploration of the MSSM with Non-Universal Higgs Masses

We explore the parameter space of the minimal supersymmetric extension of the Standard Model (MSSM), allowing the soft supersymmetry-breaking masses of the Higgs multiplets, m_{1,2}, to be non-universal (NUHM). Compared with the constrained MSSM (CMSSM) in which m_{1,2} are required to be equal to the soft supersymmetry-breaking masses m_0 of the squark and slepton masses, the Higgs mixing parameter mu and the pseudoscalar Higgs mass m_A, which are calculated in the CMSSM, are free in the NUHM model. We incorporate accelerator and dark matter constraints in determining allowed regions of the (mu, m_A), (mu, M_2) and (m_{1/2}, m_0) planes for selected choices of the other NUHM parameters. In the examples studied, we find that the LSP mass cannot be reduced far below its limit in the CMSSM, whereas m_A may be as small as allowed by LEP for large tan \beta. We present in Appendices details of the calculations of neutralino-slepton, chargino-slepton and neutralino-sneutrino coannihilation needed in our exploration of the NUHM.Comment: 92 pages LaTeX, 32 eps figures, final version, some changes to figures pertaining to the b to s gamma constrain

Accelerator Constraints on Neutralino Dark Matter

The constraints on neutralino dark matter \chi obtained from accelerator searches at LEP, the Fermilab Tevatron and elsewhere are reviewed, with particular emphasis on results from LEP 1.5. These imply within the context of the minimal supersymmetric extension of the Standard Model that m_\chi \ge 21.4 GeV if universality is assumed, and yield for large tan\beta a significantly stronger bound than is obtained indirectly from Tevatron limits on the gluino mass. We update this analysis with preliminary results from the first LEP 2W run, and also preview the prospects for future sparticle searches at the LHC.Comment: Presented by J. Ellis at the Workshop on the Identification of Dark Matter, Sheffield, September, 1996. 14 pages; Latex; 12 Fig

'Workshop for Nagoya Protocol and Plant Treaty National Focal Points in Latin America and the Caribbean’

The capacity-building Workshop for National Focal Points in Latin America and the Caribbean on Mutually Supportive Implementation of the Nagoya Protocol and the International Treaty on Plant Genetic Resources for Food and Agriculture, was held 25-28 September 2018 at the International Potato Center (CIP), Lima, Peru. The workshop was attended by over 60 participants, including National Focal Points for the Nagoya Protocol to the Convention on Biological Diversity and the International Treaty on Plant Genetic Resources (CBD) for Food and Agriculture (Plant Treaty), from 16 countries in Latin America and the Caribbean. The workshop was also attended by representatives from the Secretariats of the Plant Treaty and CBD, the International Seed Federation, farmer and indigenous peoples organizations, national and international agricultural research organizations and experts from the region who have been working for decades on access and benefit-sharing policy issues. The objectives of the workshop were to: 1. Strengthen network ties between National Focal Points within each country and across the regions; 2. Analyse challenges and opportunities for implementing the Plant Treaty and the Nagoya Protocol in a mutually supportive manner, and in ways that advance complementary policy goals, such as climate change adaptation, and improving the livelihoods of indigenous peoples and local communities; 3. Equip participants with tools to help address ‘real life’ scenarios where mutually supportive implementation is important, and 4. Identify the kinds of additional support that countries need to implement the Plant Treaty and Nagoya Protocol in mutually supportive ways