Matter parity as the origin of scalar Dark Matter

We extend the concept of matter parity $P_M=(-1)^{3(B-L)}$ to non-supersymmetric theories and argue that $P_M$ is the natural explanation to the existence of Dark Matter of the Universe. We show that the non-supersymmetric Dark Matter must be contained in scalar 16 representation(s) of $SO(10),$ thus the unique low energy Dark Matter candidates are $P_M$-odd complex scalar singlet(s) $S$ and inert scalar doublet(s) $H_2.$ We have calculated the thermal relic Dark Matter abundance of the model and shown that its minimal form may be testable at LHC via the SM Higgs boson decays $H_1\to DM DM.$ The PAMELA anomaly can be explained with the decays $DM\to \nu l W$ induced via seesaw-like operator which is additionally suppressed by Planck scale. Because the SM fermions are odd under matter parity too, the DM sector is just our scalar relative.Comment: The origin of scalar DM is emphasized, version accepted by PR

Implications of the 125 GeV Higgs boson for scalar dark matter and for the CMSSM phenomenology

We study phenomenological implications of the ATLAS and CMS hint of a $125\pm 1$ GeV Higgs boson for the singlet, and singlet plus doublet non-supersymmetric dark matter models, and for the phenomenology of the CMSSM. We show that in scalar dark matter models the vacuum stability bound on Higgs boson mass is lower than in the standard model and the 125 GeV Higgs boson is consistent with the models being valid up the GUT or Planck scale. We perform a detailed study of the full CMSSM parameter space keeping the Higgs boson mass fixed to $125\pm 1$ GeV, and study in detail the freeze-out processes that imply the observed amount of dark matter. After imposing all phenomenological constraints except for the muon $(g-2)_\mu,$ we show that the CMSSM parameter space is divided into well separated regions with distinctive but in general heavy sparticle mass spectra. Imposing the $(g-2)_\mu$ constraint introduces severe tension between the high SUSY scale and the experimental measurements -- only the slepton co-annihilation region survives with potentially testable sparticle masses at the LHC. In the latter case the spin-independent DM-nucleon scattering cross section is predicted to be below detectable limit at the XENON100 but might be of measurable magnitude in the general case of light dark matter with large bino-higgsino mixing and unobservably large scalar masses.Comment: 17 pages, 7 figures. v3: same as published versio

Direct determination of neutrino mass parameters at future colliders

If the observed light neutrino masses are induced by their Yukawa couplings to singlet right-handed neutrinos, natural smallness of those renders direct collider tests of the electroweak scale neutrino mass mechanisms almost impossible both in the case of Dirac and Majorana (seesaw of type I) neutrinos. However, in the triplet Higgs seesaw scenario the smallness of light neutrino masses may come from the smallness of B-L breaking parameters, allowing sizable Yukawa couplings even for a TeV scale triplet. We show that, in this scenario, measuring the branching fractions of doubly charged Higgs to different same-charged lepton flavours at LHC and/or ILC experiments will allow one to measure the neutrino mass parameters which neutrino oscillation experiments are insensitive to, including the neutrino mass hierarchy, lightest neutrino mass and Majorana phases.Comment: A mistake corrected, experimental errors revised, new references added, conclusions unchange

Long-lived charged Higgs at LHC as a probe of scalar Dark Matter

We study inert charged Higgs boson $H^\pm$ production and decays at LHC experiments in the context of constrained scalar dark matter model (CSDMM). In the CSDMM the inert doublet and singlet scalar's mass spectrum is predicted from the GUT scale initial conditions via RGE evolution. We compute the cross sections of processes $pp\to H^+H^-,\, H^\pm S_i^0$ at the LHC and show that for light $H^\pm$ the first one is dominated by top quark mediated 1-loop diagram with Higgs boson in s-channel. In a significant fraction of the parameter space $H^\pm$ are long-lived because their decays to predominantly singlet scalar dark matter (DM) and next-to-lightest (NL) scalar, $H^\pm\to S_{\text{DM, NL}} ff',$ are suppressed by the small singlet-doublet mixing angle and by the moderate mass difference $\Delta M=M_{H^+}-M_{\text{DM}} .$ The experimentally measurable displaced vertex in $H^\pm$ decays to leptons and/or jets and missing energy allows one to discover the $H^+H^-$ signal over the huge $W^+W^-$ background. We propose benchmark points for studies of this scenario at the LHC. If, however, $H^\pm$ are short-lived, the subsequent decays $S_{\text{NL}}\to S_{\text{DM}} f\bar f$ necessarily produce additional displaced vertices that allow to reconstruct the full $H^\pm$ decay chain.Comment: 15 pages, 5 figure

Dark Matter as the signal of Grand Unification

We argue that the existence of Dark Matter (DM) is a possible consequence of GUT symmetry breaking. In GUTs like SO(10), discrete Z_2 matter parity (-1)^{3(B-L)} survives despite of broken B-L, and group theory uniquely determines that the only possible Z_2-odd matter multiplets belong to representation 16. We construct the minimal non-SUSY SO(10) model containing one scalar 16 for DM and study its predictions below M_{G}. We find that EWSB occurs radiatively due to DM couplings to the SM Higgs boson. For thermal relic DM the mass range M_{DM}\sim (0.1-1) TeV is predicted by model perturbativity up to M_{G}. For M_{DM}\sim (1) TeV to explain the observed cosmic ray anomalies with DM decays, there exists a lower bound on the spin-independent direct detection cross section within the reach of planned experiments.Comment: DM direct detection cross section is corrected by adding s-quark contribution which turned out to be the dominant one. The prediction is just below the present CDMS and XENON10 bound. Extended version, RGE-s included, new references adde

The Inert Doublet Model and Inelastic Dark Matter

The annual modulation observed by DAMA/NaI and DAMA/Libra may be interpreted in terms of elastic or inelastic scattering of dark matter particles. In this paper we confront these two scenarios within the framework of a very simple extension of the Standard Model, the Inert Doublet Model (IDM). In this model the dark matter candidate is a scalar, the lightest component of an extra Higgs doublet. We first revisit the case for the elastic scattering of a light scalar WIMP, M_DM~10 GeV, a scenario which requires that a fraction of events in DAMA are channelled. Second we consider the possibility of inelastic Dark Matter (iDM). This option is technically natural in the IDM, in the sense that the mass splitting between the lightest and next-to-lightest neutral scalars may be protected by a Peccei-Quinn (PQ) symmetry. We show that candidates with a mass M_DM between ~535 GeV and ~50 TeV may reproduce the DAMA data and have a cosmic abundance in agreement with WMAP. This range may be extended to candidates as light as ~50 GeV if we exploit the possibility that the approximate PQ symmetry is effectively conserved and that a primordial asymmetry in the dark sector may survive until freeze-out.Comment: 16 pages, 7 figures. v2: minor changes and discussion on the embedding in SO(10) added. v3: matches the published version in JCA

Effective Dark Matter Model: Relic density, CDMS II, Fermi LAT and LHC

The Cryogenic Dark Matter Search recently announced the observation of two signal events with a 77% confidence level. Although statistically inconclusive, it is nevertheless suggestive. In this work we present a model-independent analysis on the implication of a positive signal in dark matter scattering off nuclei. Assuming the interaction between (scalar, fermion or vector) dark matter and the standard model induced by unknown new physics at the scale $\Lambda$, we examine various dimension-6 tree-level induced operators and constrain them using the current experimental data, e.g. the WMAP data of the relic abundance, CDMS II direct detection of the spin-independent scattering, and indirect detection data (Fermi LAT cosmic gamma-ray), etc. Finally, the LHC reach is also explored

Direct detection and CMB constraints on light DM scenario of top quark asymmetry and dijet excess at Tevatron

We study in detail the model by Isidori and Kamenik that is claimed to explain the top quark forward-backward asymmetry at Tevatron, provide GeV-scale dark matter (DM), and possibly improve the agreement between data and theory in Tevatron W+jj events. We compute the DM thermal relic density, the spin-independent DM-nucleon scattering cross section, and the cosmic microwave background constraints on both Dirac and Majorana neutralino DM in the parameter space that explains the top asymmetry. A stable light neutralino is not allowed unless the local DM density is 3-4 times smaller than expected, in which case Dirac DM with mass around 3 GeV may be possible, to be tested by the Planck mission. The model predicts a too broad excess in the dijet distribution and a strong modification of the missing E_T distribution in W+jj events.Comment: 4 pages, 4 figures; fig. 2 corrected, conclusions slightly changed, matches published versio