====== Dark matter searches at the LHC ====== ===== Projects: ===== ==== Recommendations for presenting LHC effective DM results ==== Goal - create a short document recommending: 1) How to present effective direct detection cross section limits from monojet (or mono-anything) searches while making clear the limits of the effective theory and the role of a light mediator mass. 2) What is the most useful set of operators to present results for, and how can the results be presented to be most useful for recasting to a full model. Interested people: ^Name ^ e-mail ^ | Kiel Howe | howek@stanford.edu | | Brian Shuve | bshuve@perimeterinstitute.ca | | Gordan Krnjaic | gkrnjaic@perimeterinstitute.ca | | Andreas Goudelis | andreas.goudelis@lapth.cnrs.fr | | Csaba Balazs | csaba.balazs@monash.edu | | Yun Jiang | yunjiang@ucdavis.edu | | Alex Arbey | alexandre.arbey@ens-lyon.fr | | Fawzi Boudjema| boudjema@lapth.cnrs.fr| ==== Improving sensitivity of monojet-like searches ==== Goal - determine the best set of cuts to study ISR + MET final states for single insertions of effective Dark Matter operators (for example, the Harnik et. al. razor recast) Interested people: ^Name ^ e-mail ^ | Marija Marjanovic | marija.marjanovic@cern.ch | ==== Exploring other signal channels for simplest UV completions of effective operators ==== Goal - in the region where monojet constraints allow fairly large couplings of mediators, are there other unexplored channels to look in? Possible examples: * Dijet resonance * Dijet resonance + missing energy * t-channnel mediator pair production through light DM exchange * Di-top resonance or di-vector-like-quark resonance for gluon operator Should we tie this in with paired resonances working group? Interested people: ^Name ^ e-mail ^ | Kiel Howe | howek@stanford.edu | | Brian Shuve | bshuve@perimeterinstitute.ca | | Andreas Goudelis | andreas.goudelis@lapth.cnrs.fr | | Aoife Bharucha | aoife.bharucha@desy.de | | Gordan Krnjaic | gkrnjaic@perimeterinstitute.ca| ==== Interpretation of the LHC monojet searches in terms of indirect detection and relic density ==== Goal - the monojet searches at the LHC are currently reinterpreted (in a simple effective model with one mediator and one DM particle) in terms of dark matter scattering cross-sections with matter, as in direct detection experiments. Can we set also limits on indirect detection (gamma, proton, anti-proton spectra)? And can we deduce a lower limit on the relic density? Additional questions: * which effective models are the most strongly constrained? * what if more than one mediator/operator is present? * which models are interesting? * can we reinterpret the DM direct search results in terms of LHC cross-section? Interested people: ^Name ^ e-mail ^ | Alex Arbey | alexandre.arbey@ens-lyon.fr | | Genevieve Belanger | belanger@lapth.cnrs.fr | | Andreas Goudelis | andreas.goudelis@lapth.cnrs.fr | | Nazila Mahmoudi | nazila@cern.ch | | Sacha Pukhov | pukhov@lapth.cnrs.fr | | Yun Jiang | yunjiang@ucdavis.edu | | Csaba Balazs | csaba.balazs@monash.edu | | Fawzi Boudjema| boudjema@lapth.cnrs.fr| ---- ---- ---- ====== More General Thoughts ====== **Questions:** * Reference masses for DM on mediator plots (Why 50 and 500? Why not 5 GeV) * Experimental limits on more effective operators (including interesting flavor structures?) * Is there a convention for plots that makes clear the limited validity of the effective theory? * Does anything change for t-channel mediators? * What extensions beyond monojet/monophoton searches can set stronger limits on effective operators? E.g. production in association with 3rd generation (e.g. http://xxx.lanl.gov/abs/1303.6638v1), Z/leptons + MET (e.g. http://arxiv.org/abs/1212.3352), ... * What can shape/variable analyses add to the sensitivity of these searches? (e.g. the Razor analysis in http://arxiv.org/abs/arXiv:1203.1662) **References:** LHC limits: * ATLAS 8 TeV monojet http://cdsweb.cern.ch/record/1493486 * CMS 8 TeV monojet http://cds.cern.ch/record/1525585?ln=en (figs. 8 and 9 were shown in organizing meeting) * ... Effective DM theory: * Fox et. al. http://arxiv.org/abs/1109.4398v1 (the key to understanding the plots in the CMS paper!) * Tait et. al. http://arxiv.org/abs/1108.1196 * ... Mediator production: * Dijet resonances: An et al. http://arxiv.org/abs/1202.2894v1 * Associated production: An et al. http://arxiv.org/abs/1212.2221 * and references therein ===== Beyond Effective dark matter ===== * How can limits easily be translated to models with multiple mediators / multiple effective operators? * How can the relevance (or irrelevance) of effective operator limits to full models like SUSY best be expressed? * What DM-motivated searches can not be expressed in an effective operators / single mediator picture? ===== Breit-Wigner cross-section ===== $\sigma_{LHC}(pp \to \chi \bar{\chi} +X)\sim \left|\frac{g_q g_\chi E}{(s-M_X^2)+iM_X\Gamma_X/2}\right|^2 \sim \frac{1}{\Lambda^4}$\\ where $E$ is of order the partonic center-of-mass energy.\\ Two regions to study/search * $M_X >> M_\chi, E_{cut}$ * $M_X \ge M_\chi, E_{cut}$