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2015:groups:higgs:dmhiggs:eftdm [2015/06/29 16:31] michele.frigerio [Effect of derivative couplings on dark matter collider searches] |
2015:groups:higgs:dmhiggs:eftdm [2015/08/11 11:45] michele.frigerio |
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**Chair:** Andreas Goudelis | **Chair:** Andreas Goudelis | ||
- | **Members:** Benjamin Fuks, Nishita Desai, Giacomo Polesello, Sanjoy Biswas, Suchita Kulkarni, Dipan Sengupta, Björn Herrmann, Daniel Schmeier, Daniele Barducci, Michele Frigerio | + | **Members:** Benjamin Fuks, Nishita Desai, Giacomo Polesello, Sanjoy Biswas, Suchita Kulkarni, Dipan Sengupta, Björn Herrmann, Daniel Schmeier, Daniele Barducci, Michele Frigerio, Aoife Bharucha, Genevieve Belanger |
+ | |||
+ | ** Main idea: ** | ||
+ | Would an observed excess of j+MET events allow for a distinction of the underlying model? Can the monojet pT distribution differentiate among different SM-DM couplings? An enhancement of the signal for large pT occurs if the coupling is proportional to the exchanged momentum; this happens for a derivative coupling, typically encountered, e.g., in compositeness models. | ||
+ | |||
+ | ** Simplest example: ** | ||
+ | The SM plus one singlet scalar DM, including a dim-6 operator coupling the Higgs doublet to the DM. | ||
+ | A recent reference on this model: http://inspirehep.net/record/1341060?ln=en , see section 3.1.1, in particular eq.(3.3) for the Higgs-DM-DM coupling, if somebody is interested to generate the related pT distribution... | ||
+ | |||
+ | A preliminary study of the monojet signature in this model was performed in the master thesis by Sylvain Lacroix (2013, in French): see section 3.9 for the case without derivative coupling, and section 4.3 for the addition of the derivative operator. | ||
+ | |||
+ | Notes by M.Frigerio including motivations, the simplest model, and two non-minimal models are available below. | ||
- | ** Ideas ** | ||
- | * Do existing EFT-versus-Model studies cover **all** interesting EFT operators? (What about t-channel, glu-glu-chi-chi) | ||
- | * Allow observed excesses in monoX studies at the LHC distinction of the underlying EFT models? | ||
**Useful references** | **Useful references** | ||
- | * A simple comparison of Monojet qqXX vs Dijet qqqq and Dilepton qqll limits on purely effective contact interactions | ||
- | http://arxiv.org/abs/1303.3348 | ||
- | * A study of the complementarity among monojet and dilepton searches for a variety of Z' - mediated simplified models: | + | * Composite Dark Matter and LHC Interplay |
- | http://arxiv.org/abs/1401.0221 | + | http://arxiv.org/abs/1404.7419 |
- | * An EFT "cutting" method in order to obtain consistent constraints in EFT frameworks, that is likely to be adopted by ATLAS/CMS in their analyses: | + | |
- | http://arxiv.org/abs/1502.04701 | + | * Dark Matter Constraints on Composite Higgs Models |
- | * A study of the complementarity among monojet and dijet searches for a variety of Z' - mediated simplified models (so no couplings to leptons assumed): | + | http://arxiv.org/abs/1501.05957 |
- | http://arxiv.org/abs/1503.05916 | + | |
* A rather inclusive summary on signatures of various EFT DM models | * A rather inclusive summary on signatures of various EFT DM models | ||
http://arxiv.org/abs/1506.03116 | http://arxiv.org/abs/1506.03116 | ||
+ | |||
+ | * The ATLAS/CMS Dark Matter forum summary | ||
+ | http://arxiv.org/abs/1507.00966 | ||
+ | |||
+ | * A relevant MSc thesis from a student of Michele's (in French) | ||
+ | {{:2015:groups:higgs:dmhiggs:rapport.pdf|}} | ||
**Tools** | **Tools** | ||
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https://feynrules.irmp.ucl.ac.be/wiki/DMsimp | https://feynrules.irmp.ucl.ac.be/wiki/DMsimp | ||
- | ==== Contributions from DM LHC forum conveners ==== | + | * FeynRules (with corresponding CalcHEP and UFO) model files for the singlet model, with an effective g-g-h vertex implemented for h production |
- | === Combination of results from mediator (dijet/dilepton...) and WIMP searches, in the context of simplified models=== | + | {{:2015:groups:higgs:dmhiggs:compositedmleshouches.tar|}} |
- | ==Presentation of results:== | + | |
- | * Dijet: only “certain” constraint at the LHC (if we make the DM through a mediator produced through quarks and gluons, then the mediator needs to decay into quarks and gluons). We can use gDM/gSM planes for the combination, see e.g. http://arxiv.org/abs/1503.05916 | + | |
- | * Do dilepton resonances need a specific theory and specific assumptions to be considered? | + | |
- | * Can we build a specific mapping between existing theories (e.g. RS gravitons) and DM theories, for spin-2 mediators? | + | |
- | == Design of searches == | + | |
- | * Is there any particular way of searching for mediators at the LHC that we missed? | + | |
- | * Are there other general possibilities for DM-SM interaction that would produce non-MET signatures, or otherwise not be found by looking for the two-body decay of a mediator? | + | |
- | * By ignoring gauge invariance and other considerations of a full theory, are any of the simplified models missing important, unavoidable details? | + | |
- | + | ||
- | === Benchmark models === | + | |
- | == Non-monojet signatures can be interesting due to their lower backgrounds (and the possibility of different triggering) == | + | |
- | * Example #1: mono-EW-boson. How to find a simplified model signal to use as a benchmark, where monojet constraints aren’t dominating? One possible lead: VVChiChi EFT operators from http://arxiv.org/abs/1307.5064 or http://arxiv.org/abs/1501.00907. The completion proceeds through loops so it has not been fully fleshed out. Is there any interest from the theoretical community to develop those models? | + | |
- | * Example #2: is there any Simplified DM models predicting distinctly VBF-like signal kinematics? (vs models corresponding to, say, VVchichi EFT operators) | + | |
- | == Any other classes of important classes of DM mediation left out by the current approaches? (E.g. Lepton portal?)== | + | |
- | + | ||
- | === More general questions on the assumptions we usually make for WIMP DM at colliders (only two of many…ATLAS/CMS DM Forum report soon to be published will contain more): === | + | |
- | * what are we missing out on, if we only look for Dirac DM? Side question, why are theorists more interested in that wrt Majorana/scalar/complex scalar/vector? | + | |
- | * what are the implications of the MFV assumption? Alternative way to phrase this question: how do we link better the theory of flavor and DM theories, in a way that we can respect those constraints without necessarily making the MFV assumption as a whole? | + | |
- | + | ||
- | ==== Effect of derivative couplings on dark matter collider searches ==== | + | |
- | + | ||
- | Can the monojet pT distribution differentiate among different SM-DM couplings? | + | |
- | An enhancement of the signal for large pT occurs if the coupling is proportional to the exchanged momentum; this happens for a derivative coupling. | + | |
- | + | ||
- | == Simplest example: == | + | |
- | The SM plus one singlet scalar DM, including a dim-6 operator coupling the Higgs doublet to the DM. | + | |
- | A recent reference on this model: http://inspirehep.net/record/1341060?ln=en , see section 3.1.1, in particular eq.(3.3) for the Higgs-DM-DM coupling, if somebody is interested to generate the related pT distribution... | + | |
- | + | ||
- | A preliminary study of the monojet signature in this model was performed in the master thesis by Sylvain Lacroix (2013, in French). | + | |
+ | **Micromegas results** | ||
+ | {{:2015:groups:higgs:dmhiggs:scdm-micro.tar.gz|}} | ||