SUSY-QCD Corrections to Dark Matter Annihilation in the Higgs Funnel

We compute the full O(alpha_s) SUSY-QCD corrections to dark matter annihilation in the Higgs-funnel, resumming potentially large mu tan beta and A_b contributions and keeping all finite O(m_b,s,1/tan^2 beta) terms. We demonstrate numerically that these corrections strongly influence the extraction of SUSY mass parameters from cosmological data and must therefore be included in common analysis tools such as DarkSUSY or micrOMEGAs.Comment: 4 pages, 3 (partly color) figures, version to be published in PR

Flavour Violation in Gauge-Mediated Supersymmetry Breaking Models: Experimental Constraints and Phenomenology at the LHC

We present an extensive analysis of gauge-mediated supersymmetry breaking models with minimal and non-minimal flavour violation. We first demonstrate that low-energy, precision electroweak, and cosmological constraints exclude large "collider-friendly" regions of the minimal parameter space. We then discuss various possibilities how flavour violation, although naturally suppressed, may still occur in gauge-mediation models. The introduction of non-minimal flavour violation at the electroweak scale is shown to relax the stringent experimental constraints, so that benchmark points, that are also cosmologically viable, can be defined and their phenomenology, i.e. squark and gaugino production cross sections with flavour violation, at the LHC can be studied.Comment: 29 pages, 1 table, 27 figures. Minor changes. Version published in Nucl. Phys.

Slepton production in polarized hadron collisions

We calculate cross sections and asymmetries for slepton pair production through neutral and charged electroweak currents in polarized hadron collisions for general slepton masses and including mixing of the left- and right-handed interaction eigenstates relevant for third generation sleptons. Our analytical results confirm and extend a previous calculation. Numerically, we show that measurements of the longitudinal single-spin asymmetry at the existing polarized pp collider RHIC and at possible polarization upgrades of the Tevatron or the LHC would allow for a determination of the tau slepton mixing angle and/or the associated supersymmetry breaking parameters Lambda for gauge mediation and A0 for minimal supergravity. Furthermore, the Standard Model background from tau pair production can be clearly distinguished due to the opposite sign of the associated asymmetry.Comment: 16 pages, 4 figures; Tevatron/LHC polarization and tau identification discussed, typos correcte

Precision predictions for associated gluino-gaugino production at the LHC

Now that the mass limits for gluinos have been pushed to the few-TeV range, they might only be visible at the LHC in associated production with lighter gauginos. We compute the corresponding cross section at next-to-leading logarithmic (NLL) and next-to-leading order (NLO) precision in the QCD coupling constant. The resulting expressions are implemented in the public code RESUMMINO and can be directly used in the corresponding experimental searches.Comment: 5 pages, 4 figures. Proceedings of the EPS Conference on High-Energy Physics (EPS-HEP 2017), Venice, Ital

Of Donor Coordination, Free-Riding, Darlings, and Orphans: The dependence of bilateral aid commitments on other bilateral giving

Using data from 1988 to 2007, we examine to what extent bilateral aid flows of an individual donor to a country depend on aid flows from all other bilateral and multilateral donors to that country. We thereby want to assess to what extent donor coordination, free-riding, selectivity, and common donor motivations drive bilateral aid allocation as these determinants would point to different dependence structures. Using approaches from spatial econometrics and controlling for endogeneity using an GMM framework, we find that other bilateral flows lead to a significant (but rather small) increase in aid flows from a particular donor. The effects are particularly pronounced for so-called donor 'orphans' who seem to be collectively shunned by bilateral aid donors. This suggests that donor coordination and free-riding are quantitatively less important than common donor interests and selectivity. --

Squark and Gaugino Hadroproduction and Decays in Non-Minimal Flavour Violating Supersymmetry

We present an extensive analysis of squark and gaugino hadroproduction and decays in non-minimal flavour violating supersymmetry. We employ the so-called super-CKM basis to define the possible misalignment of quark and squark rotations, and we use generalized (possibly complex) charges to define the mutual couplings of (s)quarks and gauge bosons/gauginos. The cross sections for all squark-(anti-)squark/gaugino pair and squark-gaugino associated production processes as well as their decay widths are then given in compact analytic form. For four different constrained supersymmetry breaking models with non-minimal flavour violation in the second/third generation squark sector only, we establish the parameter space regions allowed/favoured by low-energy, electroweak precision, and cosmological constraints and display the chirality and flavour decomposition of all up- and down-type squark mass eigenstates. Finally, we compute numerically the dependence of a representative sample of production cross sections at the LHC on the off-diagonal mass matrix elements in the experimentally allowed/favoured ranges.Comment: 35 pages, 29 (partly colour) figures. Some typos corrected, wording of several paragraphs improved, version accepted by Nucl. Phys.

Detailed Comparison of Next-to-Leading Order Predictions for Jet Photoproduction at HERA

The precision of new HERA data on jet photoproduction opens up the possibility to discriminate between different models of the photon structure. This requires equally precise theoretical predictions from perturbative QCD calculations. In the past years, next-to-leading order calculations for the photoproduction of jets at HERA have become available. Using the kinematic cuts of recent ZEUS analyses, we compare the predictions of three calculations for different dijet and three-jet distributions. We find that in general all three calculations agree within the statistical accuracy of the Monte Carlo integration yielding reliable theoretical predictions. In certain restricted regions of phase space, the calculations differ by up to 5%.Comment: 10 pages, 7 eps-figures. To appear in the Proceedings of the Workshop on ``Monte Carlo Generators for HERA Physics'', Hamburg 1998/9

Transverse-Momentum Resummation for Slepton-Pair Production at the LHC

We perform a first precision calculation of the transverse-momentum (q_T) distribution of slepton pair and slepton-sneutrino associated production at the CERN Large Hadron Collider (LHC). We implement soft-gluon resummation at the next-to-leading logarithmic (NLL) level and consistently match the obtained result to the pure fixed-order perturbative result at leading order (LO) in the QCD coupling constant, i.e. O(alpha_s). We give numerical predictions for stau_1 stau_1^* and stau_1 sneutrino_tau^* + stau_1^* sneutrino_tau production, also implementing recent parameterizations of non-perturbative effects. The results show a relevant contribution of resummation both in the small and intermediate q_T-regions and little dependence on unphysical scales and non-perturbative contributions.Comment: 4 pages, 2 figure