Mono-X versus direct searches: simplified models for dark matter at the LHC

Journal of High Energy Physics, Jun 2017

We consider simplified models for dark matter (DM) at the LHC, focused on mono-Higgs, -Z or -b produced in the final state. Our primary purpose is to study the LHC reach of a relatively complete set of simplified models for these final states, while comparing the reach of the mono-X DM search against direct searches for the mediating particle. We find that direct searches for the mediating particle, whether in di-jets, jets+ , multi-b+ , or di-boson+ , are usually stronger. We draw attention to the cases that the mono-X search is strongest, which include regions of parameter space in inelastic DM, two Higgs doublet, and squark mediated production models with a compressed spectrum.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2FJHEP06%282017%29082.pdf

Mono-X versus direct searches: simplified models for dark matter at the LHC

Received: December versus direct searches: simpli ed models for Seng Pei Liew 0 2 5 Michele Papucci 0 2 3 4 Alessandro Vichi 0 1 2 Kathryn M. Zurek 0 2 3 4 Open Access 0 2 c The Authors. 0 2 0 CH-1015 , Lausanne , Switzerland 1 Institute of Physics, Ecole Polytechnique Federale de Lausanne 2 Bunkyo-ku, Tokyo 113-0033 , Japan 3 Theoretical Physics Group, Lawrence Berkeley National Laboratory 4 Berkeley Center for Theoretical Physics, University of California 5 Department of Physics, University of Tokyo We consider simpli ed models for dark matter (DM) at the LHC, focused on mono-Higgs, -Z or -b produced in the nal state. Our primary purpose is to study the LHC reach of a relatively complete set of simpli ed models for these nal states, while comparing the reach of the mono-X DM search against direct searches for the mediating particle. We nd that direct searches for the mediating particle, whether in di-jets, jets+E= T , multib+E= T , or di-boson+E= T , are usually stronger. We draw attention to the cases that the mono-X search is strongest, which include regions of parameter space in inelastic DM, two Higgs doublet, and squark mediated production models with a compressed spectrum. Phenomenological Models - Sbottoms with mono-b, mono-h and mono-Z 1 Introduction 2 Simpli ed models for mono-X 2.1 \Inelastic" dark matter Two Higgs Doublet Model Squarks with mono-Z s-channel vector mediator s-channel scalar mediator 2.7 Inelastic squarks A Experimental analyses and simulation details B 14 TeV projections Introduction Dark matter (DM) production at colliders is a potentially powerful complementary probe to searches for DM in direct and indirect detection experiments. Traditionally, searches for DM at colliders have focused on the signatures of DM candidates belonging to simple, non-singlet representation of the Standard Model (SM) weak gauge group SU(2) tivaved by the most popular incarnations of the weakly interative massive particle (WIMP) ideas, such as the neutralino in supersymmetry (SUSY). More recently, however, the idea that the LHC can search for WIMP DM in more general types of theories and interactions has gained traction. That one can look for DM via a jet, photon or Z-boson recoiling o missing energy has a long history [1{7]. Casting these bounds in the context of an e ective eld theory (EFT) allows one to compare the results from a collider in a straightforward way to direct and indirect detection constraints [8{14] simply by placing a bound on the scale of the EFT operator, , that can be easily ported from one type of DM search experiment to the next. Perhaps because of this ease of comparison to direct and indirect detection experiments, DM searches at the Large Hadron Collider (LHC) have gained popularity, and the EFT framework has been utilized in many LHC searches at Run I. It is clear, however, that the typical momenta exchanged in the collision processes probed at colliders such as the LHC are often beyond the values of that can be bounded, rendering a naive EFT characterization of DM searches at colliders invalid in many cases. E ective operators within the EFT framework are generated by integrating out heavy mediators at a scale in the UV-complete theory; a lower limit on can be derived selfconsistently if the energy scale of the processes used to constrain the theory is smaller than . Further discussions and more detailed analyses of this issue can be found in [15{24]. For this reason, the collider limits obtained using the EFT approach cannot be straightforwardly used, for example, to compare with limits obtained from direct detection experiments. Various prescriptions to overcome these issues can be found, e.g., in [17, 25{28]. These statements are especially true once constraints on the mediating particle are taken into account, generally forcing one either out of the LHC reach or out of regime of validity of the EFT (e.g. [21, 24]). Identifying the regions where mono-X searches provide the strongest constraint is therefore important for developing a DM LHC search program. For example, di-jet searches for the particle mediating the DM production place such strong constraints on the quark-mediator coupling that, in order for the DM-mediator coupling to be perturbative but still constrained by mono-jet searches, one nds the mediator must, in most cases, be produced on-shell. For the purpose of DM direct detection experiments, a given scattering cross-section will map to di erent parameter points that may have di erent exclusion status between mono-jet and di-jet LHC searches, thus requiring additional assumptions. Therefore, in order to interpret DM search results at colliders adequately, simpli ed models should be employed [28]. Simpli ed models are UV-complete models that do not necessarily represent the full theory, but enable one to study the kinematics and topologies of DM production at the LHC in a precise manner. Moreover, the sensitivity comparisons between collider and direct detection limits can be performed accurately. Simpli ed models immediately suggest that other signatures, apart from looking for DM recoiling against a visible SM particle, must be considered. Searching directly for the mediator of the SM-DM interaction may generally be more powerful for constraining the parameter space. For example, returning to the earlier example, assuming that the mediator is coupled to both quarks and DM, where the monojet search is expected to be important, models with t-channel DM production (squark mediator) are constrained by jets (Z0 mediator) are constrained by di-jet searches. Various aspects of such simpli ed models have been studied extensively in the literature1 [18{24, 31{39]. Simpli ed models for mono-X searches, where here X will be taken to be an object di erent from a jet, such as mono-Higgs [40{43], mono-W [44], -Z [6, 45], and -b [46, 47] have received comparatively less attention. Understandably, one does not expect DM to be produced copiously while radiating from the initial-state a particle such as Higgs, Z or W at the LHC. In most cases, DM production with a jet from the initial state imposes the most stringent constraints. Even so, as dedicated searches for various mono-X channels have already been performed [48{54] and will be extensively carried on in the current and future LHC runs, it is important and timely to consider a relatively exhaustive set of simpli ed models that give rise dominantly to such mono-X signals. A systematic study considering 1For a comprehensive list of references, see [28{30]. a broad range of simpli ed models is still lacking in the literature. The present work aims to bridge this gap and propose a comprehensive set of simpli ed models that characterizes mono-X searches. In the following, we focus on the interplay of mono-X limits with other collider searches as well as their phenomenological implications. We also provide UV completions of these DM production topologies. Table 1 shows diagrammatically the simpli ed models in consideration for mono-Higgs and mono-Z as well as the models' constraints from other collider searches. In general, many models which feature a mono-Z signal also have a mono-W signal. For most of our analysis, we focus on singlet DM where there is only mono-Z and mono-H signals; the exception is the \inelastic squark" model, where the topology demands the presence of both mono-Z and mono-W signatures. In general, however, the constraint on the production cross-section times branching fraction is weaker for mono-W as compared to mono-Z, rendering the former less powerful, unless the latter is strongly suppressed for, e.g., kinematic reasons. We also do not further consider mono- searches [7, 55]. When the photon is radiated from the initial state, the constraint is generically weaker than when a jet is radiated from the initial state. The other options are that that photon is radiated from the mediator or from the nal state. Since the nal state is charge neutral, the latter does not occur at tree level. The photon may instead be radiated from a charged non-colored mediating particle.2 In this case a charged particle must be produced in the nal state as well, which must decay to additional charged SM states. These may be lost if they are su ciently soft, but in this case, it has been shown that mono-X searches alone are not very powerful [56], although they may provide stronger limits if complemented with other signatures present in the event, such as a soft lepton or a disappearing track [57]. The only exception is if the mediating particle is present in a t-channel in the vector-boson-fusion (VBF) topology [58]. We leave the study of the Among possible other mono-X searches there are also those where X is a bottom or top quark. Mono-b searches are very e ective for models where the mediator preferentially couples to the third generation, such as Higgs-like particles. The correspondence between mono-b and direct searches for this type of s-channel model has been thoroughly investigated in [47]. In this work, we will consider a simpli ed model with t-channel mediator (sbottom), which, as will be shown below, also plays a role in mono-h and mono-Z searches. Table 2 shows diagrammatically the mono-b topology as well as the relevant direct searches considered in this work. In the case of mono-t searches the only simpli ed models producing sizable signals at tree level are divided in two categories depending on whether mono-t is resonantly produced, as in R-parity violating (RPV) SUSY, or non-resonantly produced via a t-channel top quark [59{63]. Strictly speaking, the RPV SUSY scenario does not have a dark matter candidate, as the lightest neutralino is not stable on cosmological time scales. Moreover, both scenarios involve avor-changing neutral interactions, which potentially lead to stringent avor constraints. Furthermore, key direct searches for the RPV case involve displaced stop decays and apart from a few (very powerful) searches performed 2If the mediating particle is also colored, mono-jet searches tend to provide stronger limits than the corresponding mono-photon ones. at Run I, both experiments are ramping up search e orts for long-lived particles in Run II. Given these complications, we leave the detailed study of mono-t signatures elsewhere. In table 3, we summarize our main results: for each mono-X search studied in this paper we list the simpli ed model where it has reach. We omit simpli ed models where a given search can only exclude parameter space already ruled out by a di erent analysis. The s-channel Z0 and Higgs mediated models are brie y commented on in the next section without performing further mono-X analysis as they have been studied in detail previously [41, 42]. Our primary purpose there is to compare the mono-X analysis against other ways to look for the mediator and/or the DM particle at the LHC. In each of the subsequent models, we compare the strength of mono-Z and mono-Higgs against each other and mono-b, whenever they are relevant. These results will serve as a guideline to both theorists and experimentalists for optimizing mono-X searches. For reference, we list all relevant collider searches utilized in our analysis in table 4. For illustrating our results, we focus here on Run I searches, since a complete set of both mono-X and direct searches performed with similar amounts of integrated luminosity has been performed. At the time of writing this is not yet the case for Run II analyses with approximately 13 fb 1 . We checked and found the set of analyses released with 2015 data do not signi cantly increase the Run I limits. Therefore in the following, we will perform comparisons among di erent searches with 8 TeV data and use the available 13 TeV searches to validate the procedure we use to make our projections for the future reach, at 300 fb 1, as described in appendix B.3 The study presented here can nevertheless be updated with new Run II analyses once those are completely available. The outline of this paper is as follows. In the next section we summarize the models and analyses utilized in our comparison of mono-X searches against various searches for the mediating particle. In the following subsections, we then systematically compare the constraints for each model in table 1 and 2 from mono-X to various searches for resonances, as well as for supersymmetry. Our goal is to highlight the classes of models where mono-X constraints shed the most new light on new physics, beyond what is already constrained by more standard types of searches. Finally, we conclude. Simpli ed models for mono-X Before describing the details of each simpli ed model, we discuss the general properties and assumptions made on the models considered here. We require that: the DM is a fermionic singlet under the SM gauge group; the mono-X signatures are produced by tree-level topologies, the model have the smallest number of mediating particles for each mono-X topology 3The only exception to this rule is a boosted di-jet analysis performed for the rst time in Run II with . This analysis is important for improving the low mass limits, and we utilize it because with this luminosity we expect similar constraints as with 20 fb 1 at 8 TeV. direct searches considered in this work. We only consider pair production of DM at colliders given that DM is stable on timescales the order of the lifetime of the Universe. An s-channel vector (scalar) mediator is denoted as Z0 (S). We also use the notation of SUSY whenever a SUSY analogue is applicable to our simpli ed models. For example, q~ denotes the t-channel colored mediator that couples to a quark (q) and DM ( ). Other auxiliary particles may be needed for constructing our simpli ed models. They are de ned accordingly in the respective subsection describing the details of the simpli ed model. exclude part of the parameter space not already ruled out by some other search. Model where it matters Inelastic DM, 2HDM Inelastic DM, 2HDM Squark mediated production, compressed spectrum Sbottom mediated production, compressed spectrum Simpli ed model (uL;R; dL;R; cL;R; sL;R) scalar mediator vector mediator Inelastic Squarks searches compared multi-jet + E= T multi-b jets + E= T multi-jet + E= T results of [24] results of [24] results of [41] results of [41] simpli ed model [64] simpli ed model [65] diboson + E= T bosons + jets + E= T simpli ed model [66, 67] simpli ed model [68] ered in this work. indicates whether we perform a full reinterpretation, use the results published by the experimental collaborations, or utilize previous work in the literature. Given this set of rules, one can nd the list of all the possible topologies and embed each of them in the minimal incarnation of a simpli ed model as de ned above. We relax the requirement of singlet DM only for the case of the inelastic squark model, where the topology we consider requires the DM to take on SM quantum numbers. These requirements are also easy to understand: focusing on singlet DM stems from the fact that searches for DM belonging to weak doublets or triplets are more mature due to the extensive program for SUSY searches. Restricting our focus to tree level topologies and keeping the number of mediators to a minimum instead originates from the attempt to maximize the reach potential of mono-X searches in comparison to direct searches for the mediators. For the purpose of illustrating the strength of mono-X and direct searches relevant to these simpli ed models, we either perform Monte Carlo event simulation, or make use of results of previous works in the literature and as presented by the experimental collaborations. We do not perform full scans in the parameter space of each model, but rather focus on slices of parameter space we believe are highlighting the main qualitative features of the comparisons between mono-X and other searches. A full parameter scan can in principle be performed but it is beyond the scope of this work. We summarize the methods and analyses employed for the simpli ed models in table 4. The details of the experimental analyses and our simulations, as well as our method of obtaining 14 TeV projections, are elaborated in appendices A, B. \Inelastic" dark matter We begin by considering a Higgs or Z radiated in the nal state through the process are produced via a resonant Z0. Here, 0 is an \excited" state of DM that decays to DM along with a Higgs or Z. These processes arise from interaction Lagrangians of the form Z0 0 0. In order for mono-h or mono-Z to be dominant, production of 0 0 (which leads to di-boson signatures) (which will be dominated by mono-jet) must be suppressed relative to discuss a concrete model where the mono-boson signature dominates. For concreteness, we focus on the case where only the right-handed up-quarks (all three generations) are charged under a new gauge symmetry.4 In addition, a new SM singlet Dirac fermion charged under U(1)Z0 is introduced as a doublet of DM. Moreover, we introduce a SM singlet scalar S that is charged under U(1)Z0 . It plays the roles of giving the Z0 a mass and acting as a \portal" to the Higgs. We also assume that some of the SM quarks are charged under it, to allow a qqZ0 coupling. In the following we will allow only = ( )) Lagrangian to be: LDM = 4This model requires the introduction of extra (spectator) fermions to achieve anomaly cancellation. coupling between SM quarks and the new gauge boson Z0, and MZ0 is the mass of Z0 [31, 69]. To focus on the more generic collider signatures of the model, we consider these spectator fermions to be su ciently heavy (achievable by saturating the aforementioned mass upper limit), such that LHC constraints on them bilinear terms are written as: = @ + igX q X^ . We de ne new bases 1 ; 2 = 1=p2( ) and new couplings 2 such that, after the U(1)Z0 symmetry is spontaneously broken, the fermion Introducing the mass eigenstates (with abbreviations c the mixing angle and mass eigenvalues are given by M 2; 0 = the DM doublet is as follows: In the new basis, is the DM candidate while 0 is the \excited" state of DM. S and Z0 mix with the SM Higgs and Z respectively, and facilitate the mono-X proZ. The interaction of the scalar eld S sc:int = p while the interaction of Z0 with the DM doublet is: signature) becomes dominant. between the U(1) gauge bosons: = 2gX q s c ( 0X=^ 0 s2 )( X=^ 0 + 0X=^ ): Let us note that at the limit where the mixing angle ! 0, the couplings of Z0 to 0 0 (leading to di-boson signature) vanish, and the 0 production (leading to mono-boson Z mixing originates from the radiative corrections that lead to kinetic mixing KE = where is expected to have the size sector Lagrangian of the model is written as: gX g0=16 2 . 10 3 from fermion loops. The Higgs U(1)X is broken spontaneously by hSi, and electroweak symmetry is broken spontaneously other after spontaneous symmetry breaking. Whether 0 decays to h or Z mainly depends from 8 TeV data. 0 is assumed to have a 100% decay to Z . The solid lines correspond to the prediction of the model when the coupling of Z0 to the quarks gqqZ0 is chosen to be equal to the upper limit consistent with di-jet constraints at a given Z0 mass (see gure 17). Panels (a)-(d) correspond to the choice of the mass parameters (mDM; GeV, respectively, where mDM is the mass splitting. The four colors represent the four from 8 TeV data. 0 is assumed to have a 100% decay to h . The solid lines correspond to the prediction of the model when the coupling of Z0 to the quarks gqqZ0 is chosen to be equal to the upper limit consistent with di-jet constraints at a given Z0 mass (see gure 17). Panels (a)-(d) correspond to the choice of the mass parameters (mDM; GeV, respectively, where mass splitting. The four colors represent the four on the value of and , which are in principle free parameters. We also note that the elastic scattering of DM o nucleons via Z0 is suppressed as long as We compare the constraints from mono-h and mono-Z analyses on the cross-section times branching fraction in gures 1, 2. We investigate four benchmark points which have di erent combinations of DM mass mDM (10 GeV and 150 GeV) and (200 GeV and 450 GeV). We can see in these two gures that both nal states can to quarks gqqZ0 to saturate the di-jet resonance search constraints at a given Z0 mass (see gure 17). In addition, we vary the DM-Z0 coupling (gDM) and show in gure 3 the 95% compare future projections for 14 TeV mono-h and mono-Z analyses in gure 4, taking a production cross-section for large mediator mass is vastly improved at increased center of Two Higgs Doublet Model We consider the resonant production of a new heavy gauge boson Z0 which decays to Higgs (Z) and a CP-odd (CP-even) scalar A0 (H), as considered in [42]. The CP-odd (CP-even) scalar then is taken to exclusively decay into a pair of DM particles. The dominant monoX signal is therefore mono-Higgs or mono-Z. In general, the simpli ed model Lagrangian of this topology can be written as: Let us consider a UV completion of this DM production topology in order to make concrete comparisons of collider constraints as well as precision electroweak constraints. Our model and analysis follow ref. [42] closely, though here we perform the mono-Z analysis for the rst time and update the mono-h constraints with newer di-jet limits. We introduce a two Higgs doublet model (2HDM) with Type-II Yukawa structure (Hu; Hd), i.e. Hu couples with u-type quarks while Hd couples with d-type quarks and charged leptons. Following ref. [42], we assume that only Hu and uR are charged under the new gauge symmetry U(1)Z0 (the charge for both Hu and uR is assumed to be 1/2). The U(1)Z0 gauge symmetry is assumed to be broken spontaneously above the electroweak scale due to a new SM singlet scalar. The physical Higgs bosons can be parametrized as follows: Hu = p Hd = p H + i cos MET>150 GeV (mono-Z) MET>250 GeV (mono-Z) MET>150 GeV (mono-h) MET>200 GeV (mono-h) MET>150 GeV (mono-Z) MET>250 GeV (mono-Z) MET>150 GeV (mono-h) MET>200 GeV (mono-h) MET>150 GeV (mono-Z) MET>250 GeV (mono-Z) MET>150 GeV (mono-h) MET>200 GeV (mono-h) MET>150 GeV (mono-Z) MET>250 GeV (mono-Z) MET>150 GeV (mono-h) MET>200 GeV (mono-h) of the Z 0 mass from mono-Z and mono-h searches at 8 TeV. The coupling of Z 0 to the quarks gqqZ0 is chosen to be equal to the upper limit consistent with di-jet constraints at a given Z 0 mass gure 17). Panels (a)-(d) correspond to the choice of the mass parameters (mDM; mDM) = (10; 200); (10; 450); (150; 200); (150; 450) in GeV, respectively. MET>400 GeV (mono-Z) MET>400 GeV (mono-h) MET>400 GeV (mono-Z) MET>400 GeV (mono-h) MET>400 GeV (mono-Z) MET>400 GeV (mono-h) MET>400 GeV (mono-Z) MET>400 GeV (mono-h) The predictions of the inelastic DM model, when the coupling of the Z0 to the quarks gqqZ0 are chosen to be equal to the upper limit consistent with di-jet constraints at a given Z0 mass (see gure 17), is shown as solid lines. Panels (a)-(d) correspond to the choice of the mass parameters Z + E= T (b,d) at p s = 8 TeV (top) and p s = 14 TeV (bottom). The left-hand gures include the contribution from hA0 together with hZ. We assume a 100% branching ratio to invisible decay y in (b,d). ET ) due to mono-Z b) in the MZ0 tan plane. c) and d) show projections at 14 TeV with 300 fb 1 The Z0 production cross section has been set to saturate current and projected dijet resonance limits respectively, as explained in the text. Contour lines for upper limits greater than 1 in are represented as dashed lines. The red curve in (c) represents the exclusion limit obtained from the less stringent cut E= T exploited a di erent analysis [70]. 300GeV and closely mimics the limit obtained in [42] which, however, We take the decoupling limit (sin ( ) = 1) so that the lighter CP-even Higgs is SM-like. Spontaneous symmetry breaking in the Higgs sector induces mixing between Z0 and the SM Z boson proportional to tan . The mixing is constrained by the precision electroweak measurement of the deviation of m2W =m2Z cos W from unity [42]: = 1 + 2 where m0Z is the SM Z boson mass in the absence of mixing. Furthermore, as uR is charged under the new U(1)Z0 gauge symmetry, di-jet resonance searches for the Z0 performed at hadron colliders constrain the Z0 coupling to the initial state quarks (see gure 17). We apply these constraints and take the coupling of the Z0 to the initial state quarks (gqqZ0 ) to saturate the combined constraints. The couplings of Z0 to hA0 and ZH, which lead to mono-Higgs and mono-Z signals, arise from the covariant derivative of the kinetic term of Hu. We show in gure 5 the dependence of mono-Higgs and mono-Z production crosssections at 8 and 14 TeV on the Z0 mass and tan . Both channels have similar dependence on the parameter space because the Z0A0h and Z0ZH couplings are both inversely proportional to tan , but mono-Z covers a larger parameter space with the same production cross-section. In gures 6 a) and b), we vary the branching ratio of A0 and H to DM and show the mono-Higgs and mono-Z constraints on the Z0 mass-tan plane. The 14 TeV projection, performed with the procedure described in appendix B, is shown in gure 6 c) and d). Here again, we nd that the mono-Z channel is able to constrain a larger parameter region compared to the corresponding mono-Higgs channel. Let us again note that whether DM couples to A0 or H largely depends on the UV completion in the dark sector. Hence, both mono-Higgs and mono-Z searches are equally useful for constraining this type of simpli ed model. Squarks with mono-Z We now consider a scenario which, in SUSY notation, involves a singlino as DM and 8 squarks as mediators: QeiLQiL + u~iRuiR + d~iRdiR + mass terms + h:c: Let us note that for the case where the mixing between left and right-handed squarks is zero, the mono-Higgs production cross-section is highly suppressed by the negligibly small quark masses. Although it is possible to introduce A-terms that could enhance the monoHiggs signal, this would in general lead to severe tuning in the quark Yukawa couplings (see e.g. [35]). Hence, we opt to leave out this possibility in this work. This is essentially the simpli ed model proposed in ref. [45] and used by the ATLAS collaboration to present their mono-Z searches at Run I [48]. We show in gure 7 the constraint on gDM as a and the right panel shows the 14 TeV projection with 300 fb 1 . The shaded region corresponds to are taken from ref. [71]. function of the mediating squark mass. We can see that in comparison to the mono-jets very weak. 14 TeV projections, performed with the procedure described in appendix B, are shown in the right panel of gure 7. They improve the constraints, but are unlikely to be Mono-Z searches could in principle allow to access the compressed case, msq msq, as shown in gure 8. In this squeezed regime one can take advantage of the gluongluon initiated squark pair production, where the squarks then decay into dark matter plus soft jets. Attaching a Z boson to one of the squark lines gives a process consistent with the mono-Z cuts5 and similar to the monojet topology. Even in this case, where the direct nd that mono-Z searches are much weaker. The 14 TeV projections shown in the right panel improve the limit and are indeed able to exclude compressed spectra up to msq & 100 GeV; nevertheless direct searches for squarks will continue to be much more powerful [71]. On the other hand, as explained in appendix B, our projections do not optimize the cuts to suppress the ratio of background over signal. Furthermore, we do not have access to the bin correlations: hence we conservatively assumed a 30% uncertainty in each bin. Future studies by the experimental collaborations are likely to improve the limits presented here, though it seems unlikely they will qualitatively change our conclusions. 5This is true only for compressed spectra: a larger mass separation would give rise to hard jet that would not pass the mono-Z cuts on jet pT . lines, and 95% exclusion limits on the cross-section after cuts for DM pair production in association with a Z, shown as solid lines. The mass of the dark matter is taken in the compressed region, 8 TeV constraints and the right panel shows the 14 TeV projection with 300 fb 1 . Projections for the mono-Z analysis. on the sbottom-bottom-DM coupling. The continuous red and blue lines represent bounds from in the compressed region (blue), msb mDM = 10 GeV. At the limit gDM implicitly assumed that gDM is small enough such that sbottom pair productions are initiated solely by gluon-gluon processes, but gDM is large enough that to make sbottoms decay promptly to DM. Similarly to the squark case, we take the Lagrangian as follows L = gDM Qe3LQ3L + ~bRbiR + mass terms + ghjHSMj2(jQe3Lj2 + j~bRj2) + h:c:; where HSM is the SM Higgs doublet. Notice that we do not normalize the sbottom coupling with the Higgs boson to the bottom Yukawa coupling. We consider rst the direct sbottom 10 GeV) and compressed region (msb mDM = 10 GeV) cases. We can see that in the non-compressed region (i.e. for relatively large mass splitting between the sbottom and neutralino) the traditional sbottom searches dominate the constraints. On the other hand, in the compressed region, the mono-b search becomes important. Note that in the non Next we compare these results to mono-Z and mono-h constraints in gure 10. Again we focus on two extremal cases: light DM and a compressed spectrum, where the process of gluon-gluon initiated sbottom pair production increases substantially the cross-section. It is worth noting that di erent con gurations translate into bounds on di erent combinations of couplings. For generic mDM, the mono-Z search sets a limit on the sbottombottom-DM coupling, while mono-h constrains the combination gDM hand, in the compressed regime the dependence on gDM is lost. We show the projection at 14 TeV in gure 11, performed with the procedure described in appendix B. Our results show that the mono-Z analysis is never able to set a limit on perturbative values of the couplings. Stated in a di erent way, the cross-section rescaling needed to exclude a given point of the parameter space is nowhere close to one, both at LHC8 and LHC14, although the latter slightly improves over the former. This is not surprising, given the results of the previous subsection and the fact that the Z boson does not distinguish between (s)quarks of di erent generations. On the other hand, as shown in gure 10(c,d) the mono-h analysis is instead able to set a limit6 on the coupling gh. The bound is further improved at LHC14, as shown in s-channel vector mediator Having investigated several models that can be constrained dominantly (at least in certain regions of parameter space) by various mono-X searches, we now step back and consider models with an s-channel mediator that have been constrained previously by mono-jet, mono-Higgs and mono-Z. We rst consider the production of Higgs in association with a new massive gauge boson Z0 which subsequently decays to DM. This mono-Higgs process occurs via an schannel Z0, and has been studied previously in ref. [41]. Our purpose here is to compare the constraints obtained there with di-jet and monojet constraints on the Z0 mediator, which one expects to be important since the mediating Z0 particle has interactions with 6The limit we found makes sense because of our normalization of gh in eq. (2.15). analysis. a) Limits on the sbottom-bottom-DM coupling from a mono-Z search as a function of the eb mass. The mass of the dark matter is xed to mDM = 10 GeV. b) 95 % exclusion limits on the cross-section for the mono-Z analysis, shown as dashed lines. 95 % exclusion limits on the cross-section after cuts for DM in association with a Z decaying into leptons, shown as solid lines. mono-h search on the product gDM pgh as a function of the eb mass, where gh is the Higgs-sbottom search in the compressed regime msb mDM = 10 GeV. projections at 14 TeV. quarks as well as DM. We write the interaction Lagrangian of this simpli ed model as + gH mZ0 hZ0 Z0 : Such an interaction of a Z0 with quarks and DM can originate from a baryon number gauge symmetry U(1)B , assuming DM is also gauged under U(1)B . We further assume that the Z0 obtains its mass mZ0 from the spontaneous U(1)B symmetry breaking due to a new resonances and mono-h searches. The latter is taken from ref. [41]. We show two benchmark points: and luminosity among the analyses used. A detailed list is reported in table 5. The shaded region scalar hB gauged under U(1)B. DM production associated with a Higgs is made possible by mixing the new scalar with the SM Higgs. Z Z0 mixing is not required to reproduce the mono-h topology, and therefore the model is not constrained by precision electroweak measurements. See ref. [41] for a more detailed discussion.7 In this framework: gH = hhBi = vB; where v is the usual Higgs vev. We compare constraints from mono-Higgs to those obtained from di-jet searches for the di erent combinations of gq, gDM and gH . To perform a meaningful comparison and make contact with the analysis already performed in ref. [41] we properly rescale one of their benchmarks and translate all the bounds to the quark and Higgs couplings: 3gq = gDM = gB; gH = 3gq=2 ; where gB is the Z0 gauge coupling, while the coupling to the Higgs boson gH has been taken at the formal limit of the perturbative regime consistent with eq. (2.17) in order to 7Another simpli ed model with the same DM production topology has been considered in ref. [41], where the hZ0 production occurs via an s-channel SM Z boson. In order to observe or constrain such a process at the LHC, however, one requires large Z Z0 mixing, which has already been disfavored by precision electroweak measurements. We do not consider this simpli ed model further. maximize the constraining power of mono-Higgs analysis. The only limits not present in the the lines of ref. [24], using the minimal Z0 width resulting from the couplings in eq. (2.16). Details are provided in appendix A. The limits from di-jets are taken directly from the and much more constraining than mono-Higgs searches. For heavier Z0 masses (e.g. MZ0 ' s-channel scalar mediator We next replace the vector s-channel mediator in the previous scenario with a scalar mediator in order to realize the DM production topology in the second row of table 1. This is possible by introducing a singlet S that acts as a portal between DM and the SM Higgs: Speci cally, we consider the following Lagrangian: L = LSM + i @= + (@ S)2 (HSyMHSM)S where HSM is the SM Higgs doublet. The SM Higgs sector is, as usual: m2h(HSyMHSM) yuiHSyMQiLuiR + ydiHSMQiLdiR : (2.21) This model was also considered in ref. [41], where they found that neither mono-h nor monoZ is strongly constraining. Here we consider whether a monojet search can be constraining on the parameter space of this model. We use the parameterization of a singlet mixed with the Higgs boson, de ning HSM = p h = cos h0 + sin S0 S = sin h0 + cos S0 tan 2 = We obtain the Lagrangian in terms of the mass eigenstates h0 and S0. After the eld rede nition, the new scalar S0 couples to all quarks with strength mvq sin . In addition, all the Higgs couplings will be rescaled by a factor of cos . These shifts are taken into account in our analyses and plots. We nd that the constraints from the monojet search on such model are also generally very weak, as shown in gure 13. in order for LHC8 to be sensitive. Di erent curves correspond to di erent values of the singlet mass S. psmax and Lmax represent the maximum energy and luminosity amongst the analyses used. A detailed list is reported in table 5. Inelastic squarks Until this point our simpli ed models have demanded that the dark matter not only be charge neutral, but also a singlet. In this (last) section we consider a scenario where the dark matter is not directly coupled to a squark-like particle, but is instead produced though an additional intermediate state. Although it is possible to build such a model using only singlet dark matter, one would engineer a rather complicated construction in order to produce sizable mono-h and mono-Z signals.8 Thus, for the sake of simplicity, here we abandon the singlet requirement in favor of a more elegant and simple model. We study a model consisting of colored scalar mediators (the eight light avor squarks) and two electroweak fermion doublets (Higgisnos, He1;2) acting as the mediators. Higgsinos have a Dirac-like mass -term, and their neutral components mix with a singlino 3. Squarks couple to the singlino and He 's. The Lagrangian is: QeiLQiL + q~RiqRi QeiLqRiHe2 + qRiQeiLHe1 + h:c: This model (and its pure electroweak subsector), being a generalization of a sector of the MSSM where the SUSY relations between gauge and Yukawa couplings have been relaxed, has been considered in the literature for many applications [19, 24, 36, 75, 76]. Here, we consider the production of He through squarks in the t-channel at the LHC. He then decays into Z (H) and , giving a mono-Z (mono-h) signature. In order for the 8Such a model would consist of a squark-like particle and two neutral states ; 0. Sizable cross-section for mono-h and mono-Z are obtained through Z S mixing. Here Z0 and S are two additional vector and scalar elds. mono-h and mono-Z channels to compete with other direct searches we focus on the region of parameter space where the squarks predominantly decay to Higgsinos. In particular for our benchmark point we x the decay branching ratios of the squarks to be Br(q~ ! 1) ' 6 : 3 : 1 (this is achieved for example by choosing the ratio of the couplings gH =gDM to be p5). Furthermore, we require that e the neutrali Higgsinos to have equal branching rations for the decays into a H or a Z and the DM particle. While the full parameter space will not be explored in this paper, we identify three mass spectra as our benchmark scenarios, corresponding to non-compressed mass spectrum, compressed He - 1 mass spectrum, and compressed q~-He mass spectrum. For the scenario with non-compressed mass spectrum, the mass of 400 GeV and 60 GeV respectively. Note that the current LHC constraints on the electroweak production of electroweak-inos are irrelevant for this choice of parameters. In ad He production, the process pp ! Z=h) ! contributes to the mono-Z (h) production. The reach of mono-Z and mono-h at 8 TeV are shown in gure 14(a) on the gDM-msq plane. On the same plot we show the constraints on two constraints arise from the processes pp ! V via t-channel squarks, from the direct squark decay to the W boson (q~ ! j 1 ! j 1W ). This search tags the searches. It can be observed that the mono-Z/h search imposes weaker constraints than on the scenario with compressed He - 1 mass spectrum, with masses 450 GeV and 320 GeV respectively. Overall the limits on gDM are expectedly weakened in plot. While mono-Z/h limits are expected to improve at 14 TeV as shown in gure 14(c) Another scenario of interest lies in the compressed q~-He mass region. We take squarks to be 10 GeV heavier than He , and vary the masses of He and . Soft jets from the squark decay can escape detection, and the cascade decay of squarks contribute sizably to the gure 15, the W Z + E= T channel is more constraining than mono-Z, taking into account constraints from the QCD squark production and the process pp ! V (gDM 6= 0). In gure 16, one observes regardless of the values of gDM. In summary, we do not nd parameter space where mono-Z/h is dominant over direct searches for the inelastic squark model. It is essential to broadly explore DM simpli ed models at the LHC, elucidating how well the mono-X and direct searches constrain each simpli ed model. In this paper, we proMET > 250 GeV (mono-Z) MET > 350 GeV (mono-Z) MET > 200 GeV (mono-h) MET > 300 GeV (mono-h) ℒ= MET > 400 GeV (mono-Z) MET > 500 GeV (mono-Z) MET > 400 GeV (mono-h) MET > 500 GeV (mono-h) MET > 250 GeV (mono-Z) MET > 350 GeV (mono-Z) MET > 200 GeV (mono-h) MET > 300 GeV (mono-h) ℒ= ℒ= MET > 400 GeV (mono-Z) MET > 500 GeV (mono-Z) MET > 300 GeV (mono-h) ℒ= sion limits on the inelastic squark model, shown as dashed lines, with (a) DM mass 60 GeV, Higgsino limits are estimated using e ciency tables and cross-section upper limits given in [66{68]. Panels (c) and (d) show the 14 TeV projections at 300 fb 1 (squarks are 10 GeV heavier than 2) at 8 TeV (a). The red dashed and solid lines represent limits from the electroweakino search in the WZ + E= T nal states [66]. The electroweakino search is dominant over mono-Z in all parameter space investigated. The 14 TeV projections are shown in 10 GeV heavier than 2). The contour lines represent the values of the squark production crossnal states [67]. The electroweakino search is dominant over mono-h in all parameter space posed a set of simpli ed models covering mono-X DM production topologies thoroughly, and we provided details of possible UV completions that realize the simpli ed model DM production topologies. Each model which produces a mono-X signature through mediator decay to DM universally predicts other signatures, such as when the mediator decays back to the initial state particles that produced it (e.g. to a pair of jets). Generally, the direct search for the mediator through visible states such as di-jets and diboson will generate stronger constraints than the mono-X constraints from DM decays, even when the DM coupling to the mediating particle is at the perturbative limit. However, each mono-X search has a model, or region of parameter space, where the mono-X signature dominates. This is summarized in table 3. While mono-X signatures are not generic searches for DM, as they are typically not the dominant channel, they are a useful tool in the hunt for physics beyond the SM. Acknowledgments SPL is supported by JSPS Research Fellowships for Young Scientists and the Program for Leading Graduate Schools, MEXT, Japan. MP and KZ are supported by the DoE under contract DE-AC02-05CH11231. AV is supported by the Swiss National Science Foundation under grant no. PP00P2-163670. Experimental analyses and simulation details In this appendix, we give descriptions of experimental analyses and simulation details of our study. For reference, we list all relevant collider searches utilized in our analysis in of the cross-section limits on simpli ed models provided by experimental collaborations.9 For mono-Z and mono-h analyses we generate events and implement the cuts using the Madgraph [77], Pythia [78] and Delphes [79] pipeline. Our set of simpli ed models is implemented with the FeynRules package [80]. For all the other searches (mono-jet and rst we simulated events with MadGraph. The we showered using Pythia, which were then passed through Atom [81]. The procedure follows closely the one described in ref. [24] and we refer to it for all the details. All the simulated events used the minimal width resulting from the couplings of the simpli ed model. Upper limits on mono-X cross-sections are either taken from the experimental collaborations' reports, or extracted following the CLS prescription [82, 83]. We summarize all LHC searches used in this work in table 5. We report di-jet bounds on the uR-Z0 coupling at 95% from three di erent sources [42, 73, 84], which use di erent data sets and have somewhat di erent results, as shown in gure 17. The rst (second) only provides bounds for mZ0 300 GeV (mZ0 It should also be noted that in gure 17, Z0 presumably decays into jets with branching 9This method neglects nite width e ects, as extensively discussed in [24]. jet(s) (+E= T ) b-jet(s) (+E= T ) 2j + E= T 1j + E= T 2b + E= T 1b + E= T H(! 2b) + E= T lepton(s) (+j + E= T ) Z(! ll) + E= T Z(! ll)W (! 2j) + E= T W (! l )W (2j) + j's+E= T H + W + E= T search for refs di-jet resonance Z0 E= T > 150; 200; 300; 400 GeV E= T > 150; 250; 350; 450 GeV Constraints on gqqZ' from dijets resonance searches CMS 8TeV 20fb-1@1604.08907D ATLAS 8TeV 20fb-1 @1407.1376D CMS 13TeV 2.3fb-1@EXO-16-030D CDF RunI @1306.2629D CDF 1.96TeV 1.1fb-1 @1306.2629D MZ'@GeVD from [42, 73, 84], where di erent data sets are used to set the upper limits. For [73, 84], we have rescaled the coupling upper limits as presented in [94] by recalculating the di-jet production crosssection of the relevant processes to re ect the assumption in our model, which has Z0 coupled only ratio 100 %. In our models, Z0 can also decay into DM with a certain branching ratio, meaning that the uR-Z0 coupling given in gure 17 has to be rescaled when mZ0 > 2mDM. In our analysis, we calculate the partial width generated by the decay into DM and rescale the saturated di-jet constraints accordingly to take this into account. 14 TeV projections The 14 TeV projected signal and background events are generated using the same pipeline. The total integrated luminosity is taken to be 300 fb 1. The dominant SM background for 14 TeV (mono-Z) SM BG after cuts 8 TeV (mono-Z) SM BG after cuts E= T cut [GeV] obs. limit [fb] E= T cut [GeV] exp. limit [fb] 0.025 0.0099 0.0099 ing ratio upper limits at 95 % C.L. for the mono-Z search. The 8 TeV results (background and observed cross-section times branching ratio upper limits) are taken from [48]. The expected crosssection times branching ratio upper limits for the 14 TeV projections are estimated assuming a systematic uncertainty of 30%. The total integrated luminosity is 300 fb 1. 8 TeV (mono-h) 14 TeV (mono-h) SM BG after cuts E= T cut [GeV] SM BG after cuts obs. limit [fb] E= T cut [GeV] exp. limit [fb] at 95 % C.L. for the mono-h search. The 8 TeV results (background and observed cross-section times branching ratio upper limits) are taken from [50]. The expected cross-section times branching ratio upper limits for the 14 TeV projections are estimated assuming a systematic uncertainty of 30%. The total integrated luminosity is 300 fb 1. mono-Z is the diboson process pp ! ZZ ! l+l (200, 300, 400, 500, 650 and 800 GeV) to maintain approximately the same number of background events for the leading SM background contribution. Other event selection criteria are kept to be the same as in the 8 TeV analysis. For mono-h, the Z + jets, tt and diboson backgrounds are found to be important. Four SRs are de ned according mono-Z projections, other event selection criteria are kept to be consistent with the 8 TeV analysis. This prescription was validated by repeating it at 13 TeV and comparing it with corresponding 2016 Run II analyses when these were available and found to yield good . In order to project the mono-Z reach The expected cross-section times branching ratio upper limit for each signal region is calculated using the CLS prescription. A systematic uncertainty of 30% is assumed in our estimate. In tables 6 and 7 we summarize the current status and prospects of mono-Z and mono-h searches. Open Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. proton-anti-proton collisions and e+e 27 (1985) 577 [INSPIRE]. D 41 (1990) 2347 [INSPIRE]. proceedings of the Conference on Dark matter in astrophysics and particle physics (DARK 1998), July 20{25, Heidelberg, Germany (1998), hep-ph/9810279 [INSPIRE]. approach, Phys. Rev. D 70 (2004) 077701 [hep-ph/0403004] [INSPIRE]. Rev. D 77 (2008) 115020 [arXiv:0803.4005] [INSPIRE]. mono-photon Z0o searches, Phys. Rev. D 78 (2008) 095002 [arXiv:0809.2849] [INSPIRE]. at colliders, JHEP 09 (2010) 037 [arXiv:1002.4137] [INSPIRE]. on light majorana dark matter from colliders, Phys. Lett. B 695 (2011) 185 [arXiv:1005.1286] [INSPIRE]. on dark matter from colliders, Phys. Rev. D 82 (2010) 116010 [arXiv:1008.1783] [INSPIRE]. JHEP 12 (2010) 048 [arXiv:1005.3797] [INSPIRE]. (2011) 014028 [arXiv:1103.0240] [INSPIRE]. LHC, Phys. Rev. D 85 (2012) 056011 [arXiv:1109.4398] [INSPIRE]. [arXiv:1208.4361] [INSPIRE]. model backgrounds with LHC monojets, Phys. Lett. B 714 (2012) 267 [arXiv:1111.5331] CoGeNT and CRESST-II, Phys. Rev. D 86 (2012) 015023 [arXiv:1112.5457] [INSPIRE]. [arXiv:1307.2253] [INSPIRE]. (2014) 015011 [arXiv:1307.8120] [INSPIRE]. models at the LHC, Europhys. Lett. 102 (2013) 51001 [arXiv:1303.3348] [INSPIRE]. interacting with quarks, JHEP 11 (2013) 014 [Erratum ibid. 01 (2014) 162] [arXiv:1308.2679] [INSPIRE]. searches at colliders and direct detection experiments: Vector mediators, JHEP 01 (2015) 037 [arXiv:1407.8257] [INSPIRE]. models, JHEP 11 (2014) 024 [arXiv:1402.2285] [INSPIRE]. eld theory for dark matter searches at the LHC, part II: complete analysis for the s-channel, JCAP 06 (2014) 060 [arXiv:1402.1275] [INSPIRE]. e ective eld theory for dark matter searches at the LHC part III: analysis for the t-channel, JCAP 09 (2014) 022 [arXiv:1405.3101] [INSPIRE]. JHEP 05 (2015) 009 [arXiv:1502.04701] [INSPIRE]. of the ATLAS/CMS dark matter forum, arXiv:1507.00966 [INSPIRE]. LHC, arXiv:1409.2893 [INSPIRE]. direct detection experiments, Phys. Dark Univ. 9-10 (2015) 51 [arXiv:1409.4075] [INSPIRE]. (2012) 182 [arXiv:1202.2894] [INSPIRE]. Tevatron bounds on the dark matter direct detection cross-section for vector mediators, JHEP 07 (2012) 123 [arXiv:1204.3839] [INSPIRE]. searches, JHEP 04 (2014) 063 [arXiv:1312.5281] [INSPIRE]. Rev. D 91 (2015) 015017 [arXiv:1410.6497] [INSPIRE]. colored mediators, JHEP 05 (2014) 086 [arXiv:1403.0324] [INSPIRE]. dark sectors with monojets and dijets, JHEP 07 (2015) 089 [arXiv:1503.05916] [INSPIRE]. models, JHEP 10 (2015) 076 [arXiv:1506.06767] [INSPIRE]. consistent completions, Phys. Rev. D 95 (2017) 055027 [arXiv:1611.04593] [INSPIRE]. production, Phys. Lett. B 730 (2014) 178 [arXiv:1311.1511] [INSPIRE]. [arXiv:1312.2592] [INSPIRE]. 06 (2014) 078 [arXiv:1402.7074] [INSPIRE]. arXiv:1608.04559 [INSPIRE]. analysis, JCAP 01 (2016) 051 [arXiv:1512.00476] [INSPIRE]. dark matter at the LHC with a mono-Z, Phys. Rev. D 86 (2012) 096011 [arXiv:1209.0231] Rev. D 90 (2014) 055002 [arXiv:1404.2018] [INSPIRE]. transverse momentum in pp collisions at p D 90 (2014) 012004 [arXiv:1404.0051] [INSPIRE]. at the LHC, Phys. Rev. D 88 (2013) 063510 [arXiv:1303.6638] [INSPIRE]. [48] ATLAS collaboration, Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at p (2014) 037 [arXiv:1407.7494] [INSPIRE]. [49] ATLAS collaboration, Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at p s = 8 TeV with the ATLAS detector, Phys. Rev. Lett. 112 (2014) 041802 [arXiv:1309.4017] [INSPIRE]. [50] ATLAS collaboration, Search for dark matter produced in association with a Higgs boson decaying to two bottom quarks in pp collisions at p Phys. Rev. D 93 (2016) 072007 [arXiv:1510.06218] [INSPIRE]. s = 8 TeV with the ATLAS detector, [51] ATLAS collaboration, Search for new particles in events with one lepton and missing boson in proton-proton collisions at p [arXiv:1511.09375] [INSPIRE]. [arXiv:1403.6734] [INSPIRE]. 191 [arXiv:1307.5952] [INSPIRE]. on indirect dark matter searches: the W W nal state, Phys. Rev. D 89 (2014) 115013 D 91 (2015) 092005 [arXiv:1408.2745] [INSPIRE]. transverse momentum and vector boson tagged jets, JHEP 12 (2016) 083 [arXiv:1607.05764] [INSPIRE]. s = 8 TeV, Phys. Rev. D 93 (2016) 052011 (2016) 113013 [arXiv:1603.07739] [INSPIRE]. [arXiv:1106.6199] [INSPIRE]. the LHC, JHEP 01 (2015) 017 [arXiv:1407.7529] [INSPIRE]. Signatures of top avour-changing dark matter, JHEP 03 (2016) 060 [arXiv:1511.07463] [64] ATLAS collaboration, Search for pair-produced third-generation squarks decaying via charm quarks or in compressed supersymmetric scenarios in pp collisions at p s = 8 TeV with the ATLAS detector, Phys. Rev. D 90 (2014) 052008 [arXiv:1407.0608] [INSPIRE]. [65] ATLAS collaboration, Search for direct third-generation squark pair production in nal states with missing transverse momentum and two b-jets in p ATLAS detector, JHEP 10 (2013) 189 [arXiv:1308.2631] [INSPIRE]. s = 8 TeV pp collisions with the [66] ATLAS collaboration, Search for direct production of charginos, neutralinos and sleptons in nal states with two leptons and missing transverse momentum in pp collisions at [67] CMS collaboration, Searches for electroweak neutralino and chargino production in channels with Higgs, Z and W bosons in pp collisions at 8 TeV, Phys. Rev. D 90 (2014) 092007 [arXiv:1409.3168] [INSPIRE]. states with jets and missing transverse momentum using p data, JHEP 09 (2014) 176 [arXiv:1405.7875] [INSPIRE]. [70] ATLAS collaboration, Search for the bb decay of the Standard Model Higgs boson in [72] ATLAS collaboration, Search for squarks and gluinos with the ATLAS detector in nal s = 8 TeV proton-proton collision novel CMS technique of data scouting, Phys. Rev. Lett. 117 (2016) 031802 [74] CMS collaboration, Search for light vector resonances decaying to quarks at 13 TeV, CMS-PAS-EXO-16-030 (2016). Rev. D 85 (2012) 075003 [arXiv:1109.2604] [INSPIRE]. JHEP 06 (2011) 128 [arXiv:1106.0522] [INSPIRE]. [79] DELPHES 3 collaboration, J. de Favereau et al., DELPHES 3, a modular framework for fast simulation of a generic collider experiment, JHEP 02 (2014) 057 [arXiv:1307.6346] complete toolbox for tree-level phenomenology, Comput. Phys. Commun. 185 (2014) 2250 [81] I.-W. Kim, M. Papucci, K. Sakurai and A. Weiler, Atom: Automated Tests Of Models, in [84] ATLAS collaboration, Search for new phenomena in the dijet mass distribution using pp nal states with missing TeV, Eur. Phys. J. C 73 (2013) 2568 [arXiv:1303.2985] [INSPIRE]. transverse momentum with the ATLAS detector in p Phys. Lett. B 701 (2011) 186 [arXiv:1102.5290] [INSPIRE]. nal state in proton-proton collisions at p s = 7 TeV proton-proton collisions, s = 7 TeV, Phys. Rev. Lett. 109 events in proton-proton collisions at p [89] CMS collaboration, Search for supersymmetry in nal states with missing transverse energy and 0, 1, 2, or at least 3 b-quark jets in 7 TeV pp collisions using the variable T , JHEP 01 (2013) 077 [arXiv:1210.8115] [INSPIRE]. large missing transverse momentum in pp collisions at p s = 8 TeV with the ATLAS detector, Eur. Phys. J. C 75 (2015) 299 [arXiv:1502.01518] [INSPIRE]. events with a jet and missing transverse momentum with the ATLAS detector, JHEP 04 pp collisions at p [93] CMS collaboration, Search for dark matter and large extra dimensions in monojet events in [1] O. Nachtmann , A. Reiter and M. Wirbel , Single jet and single photon production in annihilation in a supersymmetric model , Z. Phys . C [2] D.A. Dicus , S. Nandi and J. Woodside , Collider signals of a superlight gravitino , Phys. Rev. [3] A. Brignole , F. Feruglio , M.L. Mangano and F. Zwirner , Signals of a superlight gravitino at hadron colliders when the other superparticles are heavy, Nucl . Phys . B 526 ( 1998 ) 136 [Erratum ibid . B 582 ( 2000 ) 759] [hep-ph/9801329] [INSPIRE]. [4] M. Brhlik , SUSY dark matter: Direct searches versus collider experiments , in the [5] A. Birkedal , K. Matchev and M. Perelstein , Dark matter at colliders: a model independent [6] F.J. Petriello , S. Quackenbush and K.M. Zurek , The invisible Z0 at the CERN LHC , Phys. [7] Y. Gershtein , F. Petriello , S. Quackenbush and K.M. Zurek , Discovering hidden sectors with [8] M. Beltran , D. Hooper , E.W. Kolb , Z.A.C. Krusberg and T.M.P. Tait , Maverick dark matter [9] J. Goodman , M. Ibe , A. Rajaraman , W. Shepherd , T.M.P. Tait and H.-B. Yu , Constraints [10] J. Goodman , M. Ibe , A. Rajaraman , W. Shepherd , T.M.P. Tait and H.-B. Yu , Constraints [11] Y. Bai , P.J. Fox and R. Harnik , The Tevatron at the frontier of dark matter direct detection , [12] P.J. Fox , R. Harnik , J. Kopp and Y. Tsai , LEP shines light on dark matter , Phys. Rev. D 84 [13] P.J. Fox , R. Harnik , J. Kopp and Y. Tsai , Missing energy signatures of dark matter at the [14] Y. Bai and T.M.P. Tait , Searches with mono-leptons , Phys. Lett . B 723 ( 2013 ) 384 [15] A. Friedland , M.L. Graesser , I.M. Shoemaker and L. Vecchi , Probing nonstandard standard [16] I.M. Shoemaker and L. Vecchi , Unitarity and monojet bounds on models for DAMA, [17] G. Busoni , A. De Simone , E. Morgante and A. Riotto , On the validity of the e ective eld theory for dark matter searches at the LHC , Phys. Lett . B 728 ( 2014 ) 412 [18] S. Chang , R. Edezhath , J. Hutchinson and M. Luty , E ective WIMPs, Phys. Rev. D 89 [19] H. An , L.-T. Wang and H. Zhang , Dark matter with t-channel mediator: a simple step beyond contact interaction , Phys. Rev. D 89 ( 2014 ) 115014 [arXiv:1308.0592] [INSPIRE]. [20] Y. Bai and J. Berger , Fermion portal dark matter , JHEP 11 ( 2013 ) 171 [arXiv:1308.0612] [21] H. Dreiner , D. Schmeier and J. Tattersall , Contact interactions probe e ective dark matter [22] A. DiFranzo , K.I. Nagao , A. Rajaraman and T.M.P. Tait , Simpli ed models for dark matter [23] O. Buchmueller , M.J. Dolan , S.A. Malik and C. McCabe , Characterising dark matter [24] M. Papucci , A. Vichi and K.M. Zurek , Monojet versus the rest of the world I: t-channel [25] G. Busoni , A. De Simone , J. Gramling , E. Morgante and A. Riotto , On the validity of the [26] G. Busoni , A. De Simone , T. Jacques , E. Morgante and A. Riotto , On the validity of the [27] D. Racco , A. Wulzer and F. Zwirner , Robust collider limits on heavy-mediator dark matter , [28] D. Abercrombie et al., Dark matter benchmark models for early LHC Run-2 searches: report [29] J. Abdallah et al., Simpli ed models for dark matter and missing energy searches at the [ 30] S.A. Malik et al., Interplay and characterization of dark matter searches at colliders and in [31] H. An , X. Ji and L.-T. Wang , Light dark matter and Z0 dark force at colliders , JHEP 07 [32] M.T. Frandsen , F. Kahlhoefer , A. Preston , S. Sarkar and K. Schmidt-Hoberg , LHC and [33] A. Alves , S. Profumo and F.S. Queiroz , The dark Z0 portal: direct, indirect and collider [34] M.R. Buckley , D. Feld and D. Goncalves , Scalar simpli ed models for dark matter , Phys. [36] M. Garny , A. Ibarra , S. Rydbeck and S. Vogl , Majorana dark matter with a coloured mediator: collider vs. direct and indirect searches , JHEP 06 ( 2014 ) 169 [arXiv:1403.4634] [37] M. Chala , F. Kahlhoefer , M. McCullough , G. Nardini and K. Schmidt-Hoberg , Constraining [38] A. Alves , A. Berlin , S. Profumo and F.S. Queiroz , Dirac-fermionic dark matter in U(1)X [39] D. Goncalves , P.A.N. Machado and J.M. No , Simpli ed models for dark matter face their [40] A.A. Petrov and W. Shepherd , Searching for dark matter at LHC with Mono-Higgs [41] L. Carpenter , A. DiFranzo , M. Mulhearn , C. Shimmin , S. Tulin and D. Whiteson , Mono-Higgs-boson: a new collider probe of dark matter , Phys. Rev. D 89 (2014) 075017 [42] A. Berlin , T. Lin and L.-T. Wang , Mono-Higgs detection of dark matter at the LHC , JHEP [43] K. Ghorbani and L. Khalkhali , Mono-Higgs signature in fermionic dark matter model , [44] N.F. Bell , Y. Cai and R.K. Leane , Mono-W dark matter signals at the LHC : simpli ed model [45] N.F. Bell , J.B. Dent , A.J. Galea , T.D. Jacques , L.M. Krauss and T.J. Weiler , Searching for [46] T. Lin , E.W. Kolb and L.-T. Wang , Probing dark matter couplings to top and bottom quarks [47] E. Izaguirre , G. Krnjaic and B. Shuve , The Galactic Center excess from the bottom up , Phys. [55] N. Lopez , L.M. Carpenter , R. Cotta , M. Frate , N. Zhou and D. Whiteson , Collider bounds [56] S. Gori , S. Jung and L.-T. Wang , Cornering electroweakinos at the LHC , JHEP 10 ( 2013 ) [57] G.F. Giudice , T. Han , K. Wang and L.-T. Wang , Nearly degenerate gauginos and dark matter at the LHC , Phys. Rev . D 81 ( 2010 ) 115011 [arXiv:1004.4902] [INSPIRE]. [58] J. Brooke et al., Vector boson fusion searches for dark matter at the LHC , Phys. Rev. D 93 [52] CMS collaboration, Search for physics beyond the standard model in nal states with a [53] CMS collaboration, Search for dark matter in proton-proton collisions at 8 TeV with missing [54] CMS collaboration, Search for dark matter and unparticles produced in association with a Z [59] J. Andrea , B. Fuks and F. Maltoni , Monotops at the LHC , Phys. Rev . D 84 ( 2011 ) 074025 [60] J. Wang , C.S. Li , D.Y. Shao and H. Zhang , Search for the signal of monotop production at the early LHC , Phys. Rev . D 86 ( 2012 ) 034008 [arXiv:1109.5963] [INSPIRE]. [61] J.-L. Agram , J. Andrea , M. Buttignol , E. Conte and B. Fuks , Monotop phenomenology at the Large Hadron Collider , Phys. Rev . D 89 ( 2014 ) 014028 [arXiv:1311.6478] [INSPIRE]. [62] I. Boucheneb , G. Cacciapaglia , A. Deandrea and B. Fuks , Revisiting monotop production at [63] J. D'Hondt, A. Mariotti , K. Mawatari , S. Moortgat , P. Tziveloglou and G. Van Onsem , [69] J. Preskill , Gauge anomalies in an e ective eld theory , Annals Phys . 210 ( 1991 ) 323 [68] ATLAS collaboration, Search for squarks and gluinos in events with isolated leptons , jets [71] T. Cohen et al., SUSY simpli ed models at 14, 33 and 100 TeV proton colliders , JHEP 04 [75] R. Mahbubani and L. Senatore , The minimal model for dark matter and uni cation , Phys. [76] T. Cohen , J. Kearney, A. Pierce and D. Tucker-Smith , Singlet-doublet dark matter , Phys. [77] J. Alwall , M. Herquet , F. Maltoni , O. Mattelaer and T. Stelzer , MadGraph 5: going beyond, [78] T. Sjostrand , S. Mrenna and P.Z. Skands , A brief introduction to PYTHIA 8. 1 , Comput . [80] A. Alloul , N.D. Christensen , C. Degrande , C. Duhr and B. Fuks , FeynRules 2.0 | A [82] G. Cowan , K. Cranmer , E. Gross and O. Vitells , Asymptotic formulae for likelihood-based tests of new physics , Eur. Phys. J. C 71 ( 2011 ) 1554 [Erratum ibid . C 73 ( 2013 ) 2501] [83] B. Mistlberger and F. Dulat , Limit setting procedures and theoretical uncertainties in Higgs [85] CMS collaboration, Search for new physics in the multijet and missing transverse nal state in proton-proton collisions at ps= 8 TeV , JHEP 06 ( 2014 ) 055 [86] CMS collaboration, Search for supersymmetry in hadronic [87] ATLAS collaboration, Search for squarks and gluinos using nal states with jets and missing [88] CMS collaboration, Search for new physics in the multijet and missing transverse [90] ATLAS collaboration, Search for new phenomena in nal states with an energetic jet and [91] CMS collaboration, Search for dark matter, extra dimensions and unparticles in monojet s = 8 TeV, Eur . Phys. J. C 75 ( 2015 ) 235 [92] ATLAS collaboration, Search for dark matter candidates and large extra dimensions in [94] B.A. Dobrescu and F. Yu , Coupling-mass mapping of dijet peak searches , Phys. Rev. D 88


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2FJHEP06%282017%29082.pdf

Seng Pei Liew, Michele Papucci, Alessandro Vichi, Kathryn M. Zurek. Mono-X versus direct searches: simplified models for dark matter at the LHC, Journal of High Energy Physics, 2017, 1-37, DOI: 10.1007/JHEP06(2017)082