Dark Matter Detection Rates Research Articles

Nmssm with correct relic density and an additional 95 GeV Higgs boson

We investigate whether it is possible within the NMSSM to describe simultaneously a correct dark matter relic density complying with the latest null results from the LZ experiment, an extra Higgs boson with a mass of ∼95\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim 95$$\\end{document} GeV visible in the bb channel at LEP and the diphoton channel at the LHC, and the deviation of the anomalous magnetic moment of the muon from its value within the Standard Model. We find that this is still possible for a variety of dark matter annihilation mechanisms, for singlino-like but also bino-like lightest supersymmetric particles. We show the signal rates of the extra Higgs boson and the dark matter detection rates as function of the dark matter mass and annihilation mechanism. The dark matter direct detection cross section may well fall below the neutrino floor. The masses of the lightest electroweakly interacting supersymmetric particles are typically not far above 100 GeV, but not excluded due to unconventional decays.

Effective field theory of dark matter direct detection with collective excitations

We develop a framework for computing light dark matter direct detection rates through single phonon and magnon excitations via general effective operators. Our work generalizes previous calculations focused on spin-independent interactions involving the total nucleon and electron numbers $N$ (the usual route to excite phonons) and spin-dependent interactions involving the total electron spin $\mathbit{S}$ (the usual route to excite magnons), leading us to identify new responses involving the orbital angular momenta $\mathbit{L}$, as well as spin-orbit couplings $\mathbit{L}\ensuremath{\bigotimes}\mathbit{S}$ in the target. All four types of responses can excite phonons, while couplings to electron's $\mathbit{S}$ and $\mathbit{L}$ can also excite magnons. We apply the effective field theory approach to a set of well-motivated relativistic benchmark models, including (pseudo) scalar mediated interactions, and models where dark matter interacts via a multipole moment, such as a dark electric dipole, magnetic dipole or anapole moment. We find that couplings to pointlike degrees of freedom $N$ and $\mathbit{S}$ often dominate dark matter detection rates, implying that exotic materials with orbital $\mathbit{L}$ order or large spin-orbit couplings $\mathbit{L}\ensuremath{\bigotimes}\mathbit{S}$ are not necessary to have strong reach to a broad class of DM models. We highlight that phonon based crystal experiments in active R (such as SPICE) will probe light dark matter models well beyond those having a simple spin-independent interaction, including e.g., models with dipole and anapole interactions. Lastly, we make publicly available a code, $\mathsf{PhonoDark}$, which computes single phonon production rates in a wide variety of materials with the effective field theory framework.

When freeze-out precedes freeze-in: sub-TeV fermion triplet dark matter with radiative neutrino mass

We propose a minimal predictive scenario for dark matter and radiative neutrino mass where the relic abundance of dark matter is generated from a hybrid setup comprising of both thermal freeze-out as well as non-thermal freeze-in mechanisms. Considering three copies of fermion triplets and one scalar doublet, odd under an unbroken ℤ2 symmetry, to be responsible for radiative origin of neutrino mass, we consider the lightest fermion triplet as a dark matter candidate which remains under-abundant in the sub-TeV regime from usual thermal freeze-out. Late decay of the ℤ2-odd scalar doublet into dark matter serves as the non-thermal (freeze-in) contribution which not only fills the thermal dark matter deficit, but also constrains the mother particle's parameter space so that the correct relic abundance of dark matter is generated. Apart from showing interesting differences from the purely freeze-out and purely freeze-in dark matter scenarios, the model remains testable through disappearing charge track signatures at colliders, observable direct and indirect detection rates for dark matter and prediction of almost vanishing lightest neutrino mass.

Pitfalls of dark matter crossing symmetries

We explore the connection between pair production of dark matter particles at collider experiments and annihilation of dark matter in the early and late universe, with a focus on the correlation between the two time-reversed processes. We consider both a model-independent effective theory framework, where the initial and final states are assumed to not change under time reversal and concrete UV-complete models within the framework of supersymmetric extensions to the Standard Model. Even within the effective theory framework (where crossing symmetry is in some sense assumed), we find that the predictions of that symmetry can vary by orders of magnitude depending on the details of the selected effective interaction. Within the supersymmetric models we consider, we find that there is an even wilder variation in the expectations one can derive for collider observables based on cross-symmetric processes such as having a thermal relic or given indirect dark matter detection rates. We also explore additional ``pitfalls'' where na\{\i}ve crossing symmetry badly fails, including models with very light mediators leading to Sommerfeld enhancements and/or dark matter bound states.

Predictions of a natural SUSY dark matter model for direct and indirect detection experiments

The most natural region of cosmologically compatible dark matter relic density in terms of low fine-tuning in a minimal supersymmetric standard model with nonuniversal gaugino masses is the so called bulk annihilation region. We study this region in a simple and predictive SUSY-GUT model of nonuniversal gaugino masses, where the latter transform as a combination of singlet plus a nonsinglet representation of the GUT group SU(5). The model prediction for the direct dark matter detection rates is well below the present CDMS and XENON100 limits, but within the reach of a future 1Ton XENON experiment. The most interesting and robust model prediction is an indirect detection signal of hard positron events, which resembles closely the shape of the observed positron spectrum from the PAMELA experiment.

Debris flows in direct dark matter searches: The modulation effect

The effect of some possible non standard WIMP velocity distributions, like the Debris Flows recently proposed, on the direct dark matter detection rates is investigated. We find that such distributions may be deciphered from the data, especially if the time variation of the event rates due to the annual motion of the Earth is observed

Neutralino dark matter in mSUGRA/CMSSM with a 125 GeV light Higgs scalar

The minimal supergravity (mSUGRA or CMSSM) model is an oft-used frame- work for exhibiting the properties of neutralino (WIMP) cold dark matter (CDM). How- ever, the recent evidence from Atlas and CMS on a light Higgs scalar with mass $ {m_h} \simeq 125 $ GeV highly constrains the superparticle mass spectrum, which in turn constrains the neutralino annihilation mechanisms in the early universe. We find that stau and stop co-annihilation mechanisms — already highly stressed by the latest Atlas/CMS re- sults on SUSY searches — are nearly eliminated if indeed the light Higgs scalar has mass $ {m_h} \simeq 125 $ GeV. Furthermore, neutralino annihilation via the A-resonance is nearly ruled out in mSUGRA so that it is exceedingly difficult to generate thermally-produced neutralino-only dark matter at the measured abundance. The remaining possibility lies in the focus-point region which now moves out to $ {m_0} \sim 10 - 20 $ TeV range due to the required large trilinear soft SUSY breaking term A0. The remaining HB/FP region is more fine-tuned than before owing to the typically large top squark masses. We present updated direct and indirect detection rates for neutralino dark matter, and show that ton scale noble liquid detectors will either discover mixed higgsino CDM or essentially rule out thermally-produced neutralino-only CDM in the mSUGRA model.

Neutrino sector impacts SUSY dark matter

Motivated by the fact that neutrinos are massive, we study the effect of neutrino Yukawa couplings on neutralino dark matter observables within the framework of a supersymmetric seesaw. We find that neutrino couplings significantly affect the neutralino relic density in regions of parameter space where soft SUSY-breaking slepton masses and/or trilinear couplings are large. Depending on the size of the couplings, the neutralino relic density spans over an order of magnitude in the A-funnel, focus point and stop-coannihilation regions of mSUGRA. We also show that dark matter detection rates can be modified by up to several orders of magnitude.

CPviolation from the standard model to strings

A review of $\mathit{CP}$ violation from the standard model to strings is given which includes a broad landscape of particle physics models, encompassing the nonsupersymmetric four-dimensional (4D) extensions of the standard model, and models based on supersymmetry, on extra dimensions, on strings, and on branes. The supersymmetric models discussed include complex minimal supergravity unified model and its extensions, while the models based on extra dimensions include five-dimensional models including models based on warped geometry. $\mathit{CP}$ violation beyond the standard model is central to achieving the desired amount of baryon asymmetry in the Universe via baryogenesis and leptogenesis. They also affect a variety of particle physics phenomena: electric dipole moments, $g\ensuremath{-}2$, relic density and detection rates for neutralino dark matter in supersymmetric theories, Yukawa unification in grand unified and string based models, and sparticle production cross sections, and their decay patterns and signatures at hadron colliders. Additionally $\mathit{CP}$ violations can generate $\mathit{CP}$ even--$\mathit{CP}$ odd Higgs mixings, affect the neutral Higgs spectrum, and lead to phenomena detectable at colliders. Prominent among these are the $\mathit{CP}$ violation effects in decays of neutral and charged Higgs bosons. Neutrino masses introduce new sources of $\mathit{CP}$ violation which may be explored in neutrino factories in the future. Such phases can also enter in proton stability in unified models of particle interactions. The current experimental status of $\mathit{CP}$ violation is discussed and possibilities for the future outlined.

Impact of going beyond the Maxwell distribution in direct dark matter detection rates

We consider direct dark matter detection rates and investigate the difference between a standard Maxwell-Boltzmann velocity distribution and a ``realistic'' distribution like the ones extracted from numerical $N$-body simulations. Sizable differences are observed when such results are compared to the standard Maxwell-Boltzmann distribution. For a light target both the total rate and the annual modulation are reduced by $\ensuremath{\sim}25%$. For a heavy target the total rate is virtually unchanged, whereas the annual modulation is modified by up to 50%, depending on the weakly interacting massive particle mass and detector energy threshold. We also consider the effect of a possible velocity anisotropy, and the effect is found to be largest for a light target. For the realistic velocity distribution the anisotropy may reduce the annual modulation, in contrast to the Maxwell-Boltzmann case.

Collider and dark matter phenomenology of models with mirage unification

We examine supersymmetric models with mixed modulus-anomaly mediated SUSY breaking (MM-AMSB) soft terms which get comparable contributions to SUSY breaking from moduli-mediation and anomaly-mediation. The apparent (mirage) unification of soft SUSY breaking terms at Q=mu_mir not associated with any physical threshold is the hallmark of this scenario. The MM-AMSB structure of soft terms arises in models of string compactification with fluxes, where the addition of an anti-brane leads to an uplifting potential and a de Sitter universe, as first constructed by Kachru {\it et al.}. The phenomenology mainly depends on the relative strength of moduli- and anomaly-mediated SUSY breaking contributions, and on the Higgs and matter field modular weights, which are determined by the location of these fields in the extra dimensions. We delineate the allowed parameter space for a low and high value of tan(beta), for a wide range of modular weight choices. We calculate the neutralino relic density and display the WMAP-allowed regions. We show the reach of the CERN LHC and of the International Linear Collider. We discuss aspects of MM-AMSB models for Tevatron, LHC and ILC searches, muon g-2 and b->s \gamma branching fraction. We also calculate direct and indirect dark matter detection rates, and show that almost all WMAP-allowed models should be accessible to a ton-scale noble gas detector. Finally, we comment on the potential of colliders to measure the mirage unification scale and modular weights in the difficult case where mu_mir>>M_GUT.

Target dark matter detection rates in models with a well-tempered neutralino

In the post-LEP2 era, and in light of recent measurements of the cosmic abundance of colddark matter (CDM) in the universe from WMAP, many supersymmetric models tend topredict (i) an overabundance of CDM and (ii) pessimistically low rates for direct detectionof neutralino dark matter. However, in models with a ‘well-tempered neutralino’, where theneutralino composition is adjusted to give the measured abundance of CDM, theneutralino is typically of the mixed bino–wino or mixed bino–higgsino state. Alongwith the necessary enhancement to neutralino annihilation rates, these modelstend to give elevated direct detection scattering rates compared to predictionsfrom SUSY models with universal soft breaking terms. We present neutralinodirect detection cross sections from a variety of models containing a well-temperedneutralino, and find cross section asymptotes with detectable scattering rates. Theseasymptotic rates provide targets that various direct CDM detection experimentsshould aim for. In contrast, in models where the neutralino mass rather thanits composition is varied to give the WMAP relic density via either resonanceannihilation or co-annihilation, the neutralino remains essentially bino-like, and directdetection rates may be below the projected reaches of all proposed experiments.

Exploring the BWCA (Bino-Wino co-annihilation) scenario for neutralino dark matter

In supersymmetric models with non-universal gaugino masses, it is possible to have opposite-sign SU(2) and U(1) gaugino mass terms. In these models, the gaugino eigenstates experience little mixing so that the lightest SUSY particle remains either pure bino or pure wino. The neutralino relic density can only be brought into accord with the WMAP measured value when bino-wino co-annihilation (BWCA) acts to enhance the dark matter annihilation rate. We map out parameter space regions and mass spectra which are characteristic of the BWCA scenario. Direct and indirect dark matter detection rates are shown to be typically very low. At collider experiments, the BWCA scenario is typified by a small mass gap m_{\tilde Z_2}-m_{\tilde Z_1} ~ 20-80 GeV, so that tree level two body decays of \tilde Z_2 are not allowed. However, in this case the second lightest neutralino has an enhanced loop decay branching fraction to photons. While the photonic neutralino decay signature looks difficult to extract at the Fermilab Tevatron, it should lead to distinctive events at the CERN LHC and at a linear e^+e^- collider.

TeVγ-rays and the largest masses and annihilation cross sections of neutralino dark matter

Motivated by the interpretation of the recent results on the TeV gamma radiation from the Galactic center, including the new 2004 HESS data, as a by-product of dark matter particles annihilations, we address the question of the largest possible neutralino masses and pair annihilation cross sections in supersymmetric models. Extending the parameter space of minimal models, such as the mSUGRA and the mAMSB scenarios, to general soft SUSY breaking Higgs masses gives access to the largest possible pair annihilation rates, corresponding to resonantly annihilating neutralinos with maximal gaugino-higgsino mixing. Adopting a model-independent approach, we provide analytical and numerical upper limits for the neutralino pair annihilation cross section. A possible loophole is given by the occurrence of non-perturbative electro-weak resonances, a case we also consider here. We then show that a thorough inclusion of QCD effects in gluino (co-)annihilations can, in extreme scenarios, make neutralinos with masses in the hundreds of TeV range, well beyond the s-wave unitarity bound, viable dark matter candidates. Finally, we outline the ranges of neutralino masses and cross sections for models thermally producing a WMAP relic abundance, thus providing reference values for ``best-case'' indirect SUSY dark matter detection rates.

Model independent approach to focus point supersymmetry: from dark matter to collider searches

The focus point region of supersymmetric models is compelling in that it simultaneously features low fine-tuning, provides a decoupling solution to the SUSY flavor and CP problems, suppresses proton decay rates and can accommodate the WMAP measured cold dark matter (DM) relic density through a mixed bino-higgsino dark matter particle. We present the focus point region in terms of a weak scale parameterization, which allows for a relatively model independent compilation of phenomenological constraints and prospects. We present direct and indirect neutralino dark matter detection rates for two different halo density profiles, and show that prospects for direct DM detection and indirect detection via neutrino telescopes such as IceCube and anti-deuteron searches by GAPS are especially promising. We also present LHC reach prospects via gluino and squark cascade decay searches, and also via clean trilepton signatures arising from chargino-neutralino production. Both methods provide a reach out to m ∼ 1.7 TeV. At a TeV-scale linear e+e− collider (LC), the maximal reach is attained in the 12 or 13 channels. In the DM allowed region of parameter space, a (s)1/2 = 0.5 TeV LC has a reach which is comparable to that of the LHC. However, the reach of a 1 TeV LC extends out to m ∼ 3.5 TeV.

Nuclear target effect on dark matter detection rate

Expected event rates for a number of dark matter nuclear targets were calculated in the effective low-energy minimal supersymmetric standard model, provided the lightest neutralino is the dark matter Weakly Interacting Massive Particle (WIMP). These calculations allow direct comparison of sensitivities of different dark matter detectors to intermediate mass WIMPs expected from the measurements of the DArk MAtter (DAMA) experiment.

Direct detection rates for Kaluza-Klein dark matter

We consider the lightest Kaluza-Klein particle at N=1 mode (LKP) of universal extra dimension to be the candidate for Dark Matter and predict the detection rates for such particles for Germenium and NaI detectors. We have also calculated the nature of annual modulation for the signals in these two types of detectors for LKP Dark Matter. The rates with different values of speed of solar system in the Galactic rest frame are also evaluated.

Possible lower bounds for the direct detection rate of SUSY dark matter

One can expect accessible lower bounds for dark matter detection rate due to restrictions on masses of the SUSY-partners. To explore this correlation one needs a new-generation large-mass detector. The absolute lower bound for detection rate can naturally be due to spin-dependent interaction. Aimed at detecting dark matter with sensitivity higher than $10^{-5}$ event/day/kg an experiment should have a non-zero-spin target. Perhaps, the best is to create a GENIUS-like detector with both Ge-73 (high spin) and Ge-76 nuclei.

Squark-, slepton-, and neutralino-chargino coannihilation effects in the low-energy effective minimal supersymmetric standard model

Within the low-energy effective Minimal Supersymmetric extension of the Standard Model (effMSSM) we calculate the neutralino relic density taking into account slepton-neutralino, squark-neutralino and neutralino/chargino- neutralino coannihilation channels. By including squark (stop and sbottom) coannihilation channels we extend our comparative study to all allowed coannihilations and obtain the general result that all of them give sizable contributions to the reduction of the neutralino relic density. Due to these coannihilation processes some models (mostly with large neutralino masses) enter into the cosmologically interesting region for relic density, but other models leave this region. Nevertheless, in general, the predictions for direct and indirect dark matter detection rates are not strongly affected by these coannihilation channels in the effMSSM.

Slepton and neutralino or chargino coannihilations in the minimal supersymmetric standard model

Within the low-energy effective Minimal Supersymmetric extension of Standard Model (effMSSM) we calculated the neutralino relic density taking into account slepton-neutralino and neutralino-chargino/neutralino coannihilation channels. We performed comparative study of these channels and obtained that both of them give sizable contributions to the reduction of the relic density. Due to these coannihilation processes some models (mostly with large neutralino masses) enter into the cosmologically interesting region for relic density, but other models leave this region. Nevertheless, in general, the predictions for direct and indirect dark matter detection rates are not strongly affected by these coannihilation channels in the effMSSM.