Flavored Dark Matter, and Its Implications for Direct Detection and Colliders (original) (raw)
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Physical Review D, 2016
We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects Minimal Flavor Violation, and is therefore naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in which dark matter couples to right-handed charged leptons. In large regions of parameter space the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. These events exhibit a characteristic flavor pattern that may allow this class of models to be distinguished from other theories of dark matter.
Flavor and Collider Signatures of Asymmetric Dark Matter
2014
We consider flavor constraints on, and collider signatures of, asymmetric dark matter (ADM) via higher dimension operators. In the supersymmetric models we consider, RRR-parity-violating (RPV) operators carrying Bensuremath−LB\ensuremath{-}LBensuremath−L interact with nnn dark matter particles XXX through an interaction of the form W=XnmathcalOBensuremath−LW={X}^{n}{\mathcal{O}}_{B\ensuremath{-}L}W=XnmathcalOBensuremath−L, where mathcalOBensuremath−L=qensuremathelldc{\mathcal{O}}_{B\ensuremath{-}L}=q\ensuremath{\ell}{d}^{c}mathcalOBensuremath−L=qensuremathelldc, ucdcdc{u}^{c}{d}^{c}{d}^{c}ucdcdc, ensuremathellensuremathellec\ensuremath{\ell}\ensuremath{\ell}{e}^{c}ensuremathellensuremathellec. This interaction ensures that the lightest ordinary supersymmetric particle is unstable to decay into the XXX sector, leading to a higher multiplicity of final state particles and reduced missing energy at a collider. Flavor-violating processes place constraints on the scale of the higher dimension operator, impacting whether the LOSP decays promptly. While the strongest limitations on RPV from nensuremath−overlinenn\ensuremath{-}\overline{n}nensuremath−overlinen oscillations and proton decay do not apply to ADM, we analyze the constraint...
Radiative seesaw model: Warm dark matter, collider signatures, and lepton flavor violating signals
Physical Review D, 2009
Extending the standard model with three right-handed neutrinos (N k ) and a second Higgs doublet (η), odd under the discrete parity symmetry Z 2 , Majorana neutrino masses can be generated at 1-loop order. In the resulting model, the lightest stable particle, either a boson or a fermion, might be a dark matter candidate. Here we assume a specific mass spectrum (M 1 ≪ M 2 < M 3 < m η ) and derive its consequences for dark matter and collider phenomenology. We show that (i) the lightest right-handed neutrino is a warm dark matter particle that can give a ∼10% contribution to the dark matter density; (ii) several decay branching ratios of the charged scalar can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. Finally, we derive upper bounds on the right-handed neutrino Yukawa couplings from the current experimental limit on Br(µ → eγ).
Radiative seesaw: Warm dark matter, collider and lepton flavour violating signals
Physical Review D, 2009
Extending the standard model with three right-handed neutrinos (N k ) and a second Higgs doublet (η), odd under the discrete parity symmetry Z 2 , Majorana neutrino masses can be generated at 1-loop order. In the resulting model, the lightest stable particle, either a boson or a fermion, might be a dark matter candidate. Here we assume a specific mass spectrum (M 1 ≪ M 2 < M 3 < m η ) and derive its consequences for dark matter and collider phenomenology. We show that (i) the lightest right-handed neutrino is a warm dark matter particle that can give a ∼10% contribution to the dark matter density; (ii) several decay branching ratios of the charged scalar can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. Finally, we derive upper bounds on the right-handed neutrino Yukawa couplings from the current experimental limit on Br(µ → eγ).
Physical Review D, 2008
The mSUGRA parameter space corresponding to light sleptons well within the reach of LHC and relatively light squarks and gluinos (mass ≤ 1 TeV) has three regions consistent with the WMAP data on dark matter relic density and direct mass bounds from LEP 2. Each region can lead to distinct leptonic signatures from squark-gluino events during the early LHC experiments (integrated luminosity ∼ 10 fb −1 or even smaller). In the much studied stau-LSP coannihilation region with a vanishing common trilinear coupling (A 0) at the GUT scale a large fraction of the final states contain electrons and / or muons and eµτ universality holds to a good approximation. In the not so well studied scenarios with non-vanishing A 0 both LSP pair annihilation and stau-LSP coannihilation could contribute significantly to the dark matter relic density for even smaller squark-gluino masses. Our simulations indicate that the corresponding signatures are final states rich in τ-leptons while final states with electrons and muons are suppressed leading to a violation of lepton universality. These features may be observed to a lesser extent even in the modified parameter space (with non-zero A 0) where the coannihilation process dominates. We also show that the generic m-leptons + n-jets+ E / T signatures without flavour tagging can also discriminate among the three scenarios. However, the signals become more informative if the τ and b-jet tagging facilities at the LHC experiments are utilized.
Phenomenology of dark matter from A 4 flavor symmetry
Journal of High Energy Physics, 2011
We investigate a model in which Dark Matter is stabilized by means of a Z2 parity that results from the same non-abelian discrete flavor symmetry which accounts for the observed pattern of neutrino mixing. In our A4 example the standard model is extended by three extra Higgs doublets and the Z2 parity emerges as a remnant of the spontaneous breaking of A4 after electroweak symmetry breaking. We perform an analysis of the parameter space of the model consistent with electroweak precision tests, collider searches and perturbativity. We determine the regions compatible with the observed relic dark matter density and we present prospects for detection in direct as well as indirect Dark Matter search experiments.
Dark matter from minimal flavor violation
Journal of High Energy Physics, 2011
We consider theories of flavored dark matter, in which the dark matter particle is part of a multiplet transforming nontrivially under the flavor group of the Standard Model in a manner consistent with the principle of Minimal Flavor Violation (MFV). MFV automatically leads to the stability of the lightest state for a large number of flavor multiplets. If neutral, this particle is an excellent dark matter candidate. Furthermore, MFV implies specific patterns of mass splittings among the flavors of dark matter and governs the structure of the couplings between dark matter and ordinary particles, leading to a rich and predictive cosmology and phenomenology. We present an illustrative phenomenological study of an effective theory of a flavor SU(3) Q triplet, gauge singlet scalar.
Mini Review on Vector-Like Leptonic Dark Matter, Neutrino Mass, and Collider Signatures
Frontiers in Physics
We review a class of models in which the Standard Model (SM) is augmented by vector-like leptons: one doublet and a singlet, which are odd under an unbroken discrete Z 2 symmetry. As a result, the neutral component of these additional vector-like leptons are stable and behave as dark matter. We study the phenomenological constraints on the model parameters and elucidate the parameter space for relic density, direct detection and collider signatures of dark matter. In such models, we further add a scalar triplet of hypercharge two and study the consequences. In particular, after electro weak symmetry breaking (EWSB), the triplet scalar gets an induced vacuum expectation value (vev), which yield Majorana masses not only to the light neutrinos but also to vector-like leptonic doublet DM. Due to the Majorana mass of DM, the Z mediated elastic scattering with nucleon is forbidden and hence allowing the model to survive from stringent direct search bound. The DM without scalar triplet lives in a small singlet-doublet leptonic mixing region (sin θ ≤ 0.1) due to large contribution from singlet component and have small mass difference (m ∼ 10 GeV) with charged companion, the NLSP (next to lightest stable particle), to aid co-annihilation for yielding correct relic density. Both these observations change to certain extent in presence of scalar triplet to aid observability of hadronically quiet leptonic final states at LHC, while one may also confirm/rule-out the model through displaced vertex signal of NLSP, a characteristic signature of the model in relic density and direct search allowed parameter space.
Signatures from scalar dark matter with a vector-like quark mediator
Journal of Cosmology and Astroparticle Physics, 2016
We present a comprehensive study of a model where the dark matter is composed of a singlet real scalar that couples to the Standard Model predominantly via a Yukawa interaction with a light quark and a colored vector-like fermion. A distinctive feature of this scenario is that thermal freeze-out in the early universe may be driven by annihilation both into gluon pairs at one-loop (gg) and by virtual internal Bremsstrahlung of a gluon (qqg). Such a dark matter candidate may also be tested through direct and indirect detection and at the LHC; viable candidates have either a mass nearly degenerate with that of the fermionic mediator or a mass above about 2 TeV.