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DokuWiki: Dark Matter @ Nikhef Dumped with DokuWiki-Dumper v0.1.44, and uploaded with dokuWikiUploader v0.1.44.

Printed in TPU. 100% infill. Time lapse video linked below. This thing allows you to mount a flight cam to the standoffs of the Dark Matter. The original mount was too close to the flight stack for my camera, so I created one that fixes that issue. It is intended for a 25 degree uptilt, but it is not limited to 25 degrees. Very minimalist, they print quickly and are easy to install.

Tracklist: 1. The Universe Explodes Into A Billion Photons Of Pure White Light 2. Do The Supernova 3. 21st Century Man 4. Money Is Dust 5. The Multiverse Suite 6. Space Junk 7. Dark Matter 8. If You Enter The Arena You've Got To Be Prepared To Deal With The Lions 9. In The Graveyard 10. Hail To The Lovers 11. Magic Eye (To See The Sky) 12. 5776 (The Breathing Song) 13. Dark Energy 14. The Hum Of The Universe

Tracklist: 1. Show Me 2. Onto You 3. Beauty 4. Daylight Station 5. I Know 6. Connections 7. Situations 8. Your Let Down 9. Go Down 10. You Stay Up 11. Never Look 12. Red 13. Delusion 14. Never Look 15. The Only Things 16. Eternal Coast

Dark Matter

Dark Matter

"Extract of a Letter Written to the Publisher, Concerning a Factitious Stony Matter or Paste, Shining in the Dark Like a Glowing Coal, after It Bath Been a Little While Exposed to the Day- or Candle-Light" is an article from Philosophical Transactions (1665-1678), Volume 11 . View more articles from Philosophical Transactions (1665-1678) . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-101750

On dark matter 作者： Xian-Qiao Yu 1 作者单位： 1. School of Physical Science and Technology, Southwest University, Chongqing 400715, China 提交时间： 2022-06-21 摘要: In this article, I shall propose an enlightening view on the origin of dark matter abundance, in which I introduce a neutral primordial field, which is a new field beyond the standard model, the mass of the primordial field is confined in the vicinity of neutrino mass (or 1-2 orders of magnitude different from the neutrino mass). All the standard model elementary particles are produced spontaneously from this field in the Big Bang epoch of the universe and then these produced elementary particles decayed or annihilated in the well-known standard model interactions. The relic of the primordial field appears in a form of vacuum energy can not only give naturally the correct abundance of dark matter in the present universe, but provide a natural solution to the cosmological constant problem as well. We find that the conventional methods of detecting dark matter either fail or have great difficulties to detect the remaining vacuum energy of the primordial field, and how to confirm the existence of the remaining energy of the universe's original energy in experiment is still an open problem. dark matter primordial field remaining vacuum energy 来自： 余先桥 分类： 物理学 >> 基本粒子与场物理学 引用： ChinaXiv:202101.00003 (或此版本 ChinaXiv:202101.00003V5 ) doi:10.12074/202101.00003 CSTR:32003.36.ChinaXiv.202101.00003.V5 推荐引用方式： Xian-Qiao Yu.(2022).On dark matter.中国科学院科技论文预发布平台.[ChinaXiv:202101.00003] 版本历史 [V5] 2022-06-21 15:54:02 ChinaXiv:202101.00003V5 下载全文

Dark Matter and Gauge Coupling Unification in A Supersymmetry Model with Vector-like Matter 作者： Chun Liu 1 Jia-Shu Lu 1 作者单位： 1. State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China,Institute of Theoretical Physics, Chinese Academy of Sciences,P.O. Box 2735, Beijing 100190, China 提交时间： 2017-09-17 摘要: WIMP dark matter and gauge coupling unification are considered in an R-parity violating MSSM with vector-like matter. Dark matter is contained in an additional vector-like SU(2)L doublet which possesses a new U(1) gauge symmetry. The Higgs fields are extended to be in a 5 ⊕¯5 representation of SU(5). The stability of dark matter is a result of gauge symmetries, and the mass of the dark matter particle is between (1.1-1.5) TeV. Dark matter has a very small cross section with nucleis, thus the model is consistent with current dark matter direct detection experiments such as Xenon100. The model also predicts new charged and colored particles to be observed at LHC. 分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 引用： ChinaXiv:201709.00071 (或此版本 ChinaXiv:201709.00071V1 ) doi:10.12074/201709.00071 CSTR:32003.36.ChinaXiv.201709.00071.V1 推荐引用方式： Chun Liu,Jia-Shu Lu.(2017).Dark Matter and Gauge Coupling Unification in A Supersymmetry Model with Vector-like Matter.中国科学院科技论文预发布平台.[ChinaXiv:201709.00071] 版本历史 [V1] 2017-09-17 10:41:10 ChinaXiv:201709.00071V1 下载全文

Basilisk Live at Dark Matter 2 June 9 2007 Tracks: Basilisk_Live_at_Dark_Matter_2_June_9_2007 Mirrored from the Toronto Mix Tape Archive .

Thats right, diamond ars out of the way, time for smgs. See you guys soon. BTW the last 2 ars are absolutley trash at everything. They are 2 shot kills in HARDCORE. Call of Duty®: Black Ops 4 https://store.playstation.com/#!/en-us/tid=CUSA11100_00 Source: https://www.youtube.com/watch?v=1LmK04RBmyU Uploader: Ryan Nalls

Wheaton, Illinois: Theosophical Society in America, 2018. (1 hour, 10 minutes) There is an astounding amount of dark matter – over five times more than ordinary matter – yet the nature of dark matter remains an unsolved scientific problem. Fermilab scientist Dr. William Wester reveals a possible solution. If the yet-to-be-proven axion particle is the dark matter of the universe, it may solve both the dark matter issue and an unsolved problem in particle physics. Learn about the Axion Dark Matter Experiment and hear the next steps to test the axion nature of dark matter. A presentation of The Theosophical Society in America.

Wheaton, Illinois: Theosophical Society in America, 2018. (1 hour, 10 minutes) There is an astounding amount of dark matter – over five times more than ordinary matter – yet the nature of dark matter remains an unsolved scientific problem. Fermilab scientist Dr. William Wester reveals a possible solution. If the yet-to-be-proven axion particle is the dark matter of the universe, it may solve both the dark matter issue and an unsolved problem in particle physics. Learn about the Axion Dark Matter Experiment and hear the next steps to test the axion nature of dark matter. A presentation of The Theosophical Society in America.

Two component dark matter with multi-Higgs 作者： Ligong Bian 1 Tianjun Li 1,2 Jing ShuXiao-Chuan Wang a 作者单位： 1. State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China 2. School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China 提交时间： 2017-08-03 摘要: With the assistance of two extra groups, i.e., an extra hidden gauge group SU(2)D and a global U(1) group, we propose a two component dark matter (DM) model. After the symmetry SU(2)D × U(1) being broken, we obtain both the vector and scalar DM candidates. The two DM candidates communicate with the standard model (SM) via three Higgs as multi-Higgs portals. The three Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and real part of a supplement complex scalar singlet. We study relic density and direct detection of DM in three scenarios. The resonance behaviors and interplay between the two component DM candidates are represented through investigating of the relic density in the parameter spaces of the two DMs masses. The electroweak precision parameters constrains the two Higgs portals couplings (λm and δ2). The relevant vacuum stability and naturalness problem in the parameter space of λm and δ2 are studied as well. The model could alleviate these two problems in some parameter spaces under the constraints of electroweak precision observables and Higgs indirect search. 分类： 物理学 >> 基本粒子与场物理学 引用： ChinaXiv:201708.00128 (或此版本 ChinaXiv:201708.00128V1 ) doi:10.12074/201708.00128 CSTR:32003.36.ChinaXiv.201708.00128.V1 推荐引用方式： Ligong Bian,Tianjun Li,Jing ShuXiao-Chuan Wang.(2017).Two component dark matter with multi-Higgs.中国科学院科技论文预发布平台.[ChinaXiv:201708.00128] 版本历史 [V1] 2017-08-03 10:09:09 ChinaXiv:201708.00128V1 下载全文

Neutrino Constraints on Inelastic Dark Matter after CDMS II 作者： Jing Shu a Peng-fei Yin b Shou-hua Zhu b 作者单位： 1. Institute for the Physics and Mathematics of the Universe, The University of Tokyo, Chiba 277 − 8568, Japan 2. Institute of Theoretical Physics & State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, P.R. China 提交时间： 2017-08-24 摘要: We discuss the neutrino constraints from solar and terrestrial dark matter (DM) annihilations in the inelastic dark matter (iDM) scenario after the recent CDMS II results. To reconcile the DAMA/LIBRA data with constraints from all other direct experiments, the iDM needs to be light (mχ < 100 GeV) and have a large DM-nucleon cross section (σn ∼ 10−4 pb in the spin-independent (SI) scattering and σn ∼ 10 pb in the spin-dependent (SD) scattering). The dominant contribution to the iDM capture in the Sun is from scattering off Fe/Al in the SI/SD case. Current bounds from Super-Kamiokande exclude the hard DM annihilation channels, such as W+W−, ZZ, tt¯ and τ +τ −. For soft channels such as b ¯b and cc¯, the limits are loose, but could be tested or further constrained by future IceCube plus DeepCore. For neutrino constraints from the DM annihilation in the Earth, due to the weaker gravitational effect of the Earth and inelastic capture condition, the constraint exists only for small mass splitting δ < 40 keV and mχ ∼ (10, 50) GeV even in the τ +τ − channel. 分类： 物理学 >> 基本粒子与场物理学 引用： ChinaXiv:201708.00316 (或此版本 ChinaXiv:201708.00316V1 ) doi:10.12074/201708.00316 CSTR:32003.36.ChinaXiv.201708.00316.V1 推荐引用方式： Jing Shu,Peng-fei Yin,Shou-hua Zhu.(2017).Neutrino Constraints on Inelastic Dark Matter after CDMS II.中国科学院科技论文预发布平台.[ChinaXiv:201708.00316] 版本历史 [V1] 2017-08-24 14:21:59 ChinaXiv:201708.00316V1 下载全文

Dark Ambient / Vapor Ambient

Hi Its FifteeenObject04 here and i am a gamer! I've been playing since i was 3 years old and wish to become a pro gamer. Be sure to like, comment and most definitely Subscribe for all of the COD dlc info and upcoming events. Source: https://www.youtube.com/watch?v=jP4vpM-IuSo Uploader: Ryan Nalls

qav skitzo dark matter gopro session mount.

Experiments with thin ZnS(Ag) scintillators provide evidence with C.L. > 99.99% for the existence of DArk Electric Matter Objects - daemons (presumably negatively charged Planckian particles with M ~ 10^-5 g) captured from the Galactic disk into near-Earth, almost circular heliocentric orbits. Their flux at V ~ 10-15 km/s was found to be as high as f > 10^-7 cm^-2 s^-1 and vary with P = 0.5 y, with maxima in March and September. A daemon flux f ~ 10^-7 - 10^-6 cm^-2 s^-1 is capable of accounting for the Troitsk anomaly in the tritium beta-spectrum and suggests its more pronounced manifestation in future KATRIN experiment. In view of the channeling effect on iodine recoil nuclei in the NaI(Tl) crystal, the DAMA/NaI experiment is also apparently detecting a flux of daemons, f ~ 6x10^-7 cm^-2 s^-1, but in this case of those falling with V = 30-50 km/s from strongly elongated, Earth-crossing heliocentric orbits oriented in the antapex direction, as a result of which the number of events detected in the 2-6-keV interval varies with P = 1 y.

We study the distribution function (DF) of dark matter particles in haloes of mass range 10^{14}--10^{15}\Msun. In the numerical part of this work we measure the DF for a sample of relaxed haloes formed in the simulation of a standard \LambdaCDM model. The DF is expressed as a function of energy E and the absolute value of the angular momentum L, a form suitable for comparison with theoretical models. By proper scaling we obtain the results that do not depend on the virial mass of the haloes. We demonstrate that the DF can be separated into energy and angular momentum components and propose a phenomenological model of the DF in the form f_{E}(E)[1+L^{2}/(2L_{0}^{2})]^{-\beta_{\infty}+\beta_{0}}L^{-2\beta_{0}}. This formulation involves three parameters describing the anisotropy profile in terms of its asymptotic values (\beta_{0} and \beta_{\infty}) and the scale of transition between them (L_{0}). The energy part f_{E}(E) is obtained via inversion of the integral for spatial density. We provide a straightforward numerical scheme for this procedure as well as a simple analytical approximation for a typical halo formed in the simulation. The DF model is extensively compared with the simulations: using the model parameters obtained from fitting the anisotropy profile, we recover the DF from the simulation as well as the profiles of the dispersion and kurtosis of radial and tangential velocities. Finally, we show that our DF model reproduces the power-law behaviour of phase space density Q=\rho(r)/\sigma^{3}(r).

The relativistic accretion rate of dark matter by a black hole is revisited. Under the assumption that the phase space density indicator, $Q=\rho_{\infty}/\sigma^3_{\infty}$, remains constant during the inflow, the derived accretion rate can be higher up to five orders of magnitude than the classical accretion formula, valid for non-relativistic and non-interacting particles, when typical dark halo conditions are considered. For these typical conditions, the critical point of the flow is located at distances of about 30-150 times the horizon radius. Application of our results to black hole seeds hosted by halos issued from cosmological simulations indicate that dark matter contributes to no more than ~10% of the total accreted mass, confirming that the bolometric quasar luminosity is related to the baryonic accretion history of the black hole.

The transfer function $T(k)$ of dark matter (DM) perturbations during matter domination is obtained by solving the collisionless Boltzmann-Vlasov equation. We find an \emph{exact} expression for $T(k)$ for \emph{arbitrary} distribution functions of decoupled particles and initial conditions}. We find a remarkably accurate and simple approximation valid on all scales of cosmological relevance for structure formation in the linear regime. The natural scale of suppression is the free streaming wavevector at matter-radiation equality, $ k_{fs}(t_{eq}) = [{4\pi\rho_{0M}}/{[ < \vec{V}^2> (1+z_{eq})]} ]^\frac12 $. An important ingredient is a non-local kernel determined by the distribution functions of the decoupled particles which describes the \emph{memory of the initial conditions and gravitational clustering} and yields a correction to the fluid description. Distribution functions that favor the small momentum region lead to an \emph{enhancement of power at small scales} $ k > k_{fs}(t_{eq}) $. For DM thermal relics that decoupled while ultrarelativistic we find $ k_{fs}(t_{eq}) \simeq 0.003 (g_d/2)^\frac13 (m/\mathrm{keV}) [\mathrm{kpc}]^{-1} $, where $ g_d $ is the number of degrees of freedom at decoupling. For WIMPS we obtain $ k_{fs}(t_{eq}) = 5.88 (g_d/2)^\frac13 (m/100 \mathrm{GeV})^\frac12 (T_d/10 \mathrm{MeV})^\frac12 [\mathrm{pc}]^{-1} $. For $k\ll k_{fs}(t_{eq})$, $T(k) \sim 1-\mathrm{C}[k/k_{fs}(t_{eq})]^2 $ where $C =\mathrm{O}(1)$ for all cases considered and simple and accurate fits for \emph{small} scales.

The properties of the dark matter that determine its thermal relic abundance can be very different from the dark matter properties today. We investigate this possibility by coupling a dark matter sector to a scalar that undergoes a phase transition after the dark matter freezes out. If the value of Omega_DM h^2 calculated from parameters measured at colliders and by direct and indirect detection experiments does not match the astrophysically observed value, a novel cosmology of this type could provide the explanation. This mechanism also has the potential to account for the "boost factor" required to explain the PAMELA data.

We show that cold dark matter axions thermalize and form a Bose-Einstein condensate. We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.

We suggest an NMSSM scenario, motivated by dark matter constraints, that may disguise itself as a much simpler mSUGRA scenario at the LHC. We show how its non-minimal nature can be revealed, and the bino--singlino mass difference measured, by looking for soft leptons.

The general approach is that all particles with non-null rest mass are subject to the force of gravity through the inverse square law of gravitation, plus an additional term that varies with the comoving distance (UYF-Field). The model is an ΛFRW-Cosmology starting from the modification of the gravity by explicitly incorporating Mach's Principle through an additional term large-scale in the gravitation; the source of this field is the ordinary baryonic matter. It`s deduced from the Matter-radiation decoupling in the early universe. This additional term of gravity UYF result null in the inner solar system, weakly attractive in interstellar ranges, very attractive in ranges comparable to the clusters of galaxies, and repulsive in cosmic scales, in agreement with astronomical and laboratory observables. This term explains dark energy, removes the incompatibility between the density of matter and the flatness of the universe in ᴧFRW-Cosmology; allows the theoretical deduction of the Hubble-Lemaitre Law, between other relevant consequences. Additionally to discuss other relevant astrophysics consequences: Birkhoff Theorem, Virial Theorem, the missing mass of Zwicky, gravitational lenssings, the BAO and the gravitational redshift in AGN, provides an additional contribution for the gravitational redshift that increase the until an factor of ~4, which has resolved the Arp controversy. Also we show the crude explanations of Pioneer anomaly, we obtain as the additional contribution of the acceleration of gravity due to UYF-Field. It is concluded that the dark energy and the missing dark mass can be approached with the usual physics as the large-scale modification of the Gravitation.

Considerations of massive neutrinos, baryogenesis as well as fermion mass textures in the grand unified theory framework provide strong motivations for supersymmetric(SUSY) SO(10) as the theory beyond the standard model. If one wants to simultaneously solve the strong CP problem via the Peccei-Quinn mechanism, the most natural way to implement it within the framework of the SUSY SO(10) model is to have an intermediate scale ($v_{BL}$) (corresponding to B-L symmetry breaking) around the invisible axion scale of about 10$^{11}$ - 10$^{12}$ GeV. Such a scale is also desirable if $\nu_{\tau}$ is to constitute the hot dark matter (HDM) of the universe. In this paper, we discuss examples of superstring inspired SUSY SO(10) models with intermediate scales that are consistent with the low energy precision measurements of the standard model gauge couplings. The hypothesis of $b-\tau$ unification which is a successful prediction of many grand unified theories is then required of these models and the resulting prediction of $b$-quark mass is used as a measure of viability of these schemes. Detailed analysis of a model with a $v_{BL}\simeq 10^{11}$ GeV, which satisfies both the requirements of invisible axion and $\nu_{\tau}$ as HDM is presented and shown to lead to $m_b\simeq 4.9$ GeV in the one-loop approximation.

We examine the `singlet majoron model' first introduced by Chikashige, Mohapatra and Peccei as a simple extension of the standard model with massive Majorana neutrinos. We can explain both the solar and the atmospheric neutrino deficits by the oscillations between electroweak doublet and singlet neutrinos without flavor mixing. Furthermore, while some light neutrinos can be the hot dark matter, tau neutrino with mass of 8.9-24 MeV can be the cold dark matter through the interaction with the majoron. Thus, we can simultaneously explain the solar neutrino deficit, the atmospheric neutrino anomaly, and the cold and hot dark matters only with the Majorana neutrinos.

If the preon structure of quarks, leptons and gauge bosons will be proved then in the Universe during relativistic phase transition the production of nonperturbative preon condensates has been occured collective excitations of which are perceived as pseudogoldstone bosons. Dark matter consisting of pseudogoldstone bosons of familon type contains a "hot" component from massless particles and a "cold" (nonrelativistic) component from massive particles. It is shown that such dark matter was undergone to two relativistic phase transitions temperatures of which were different. In the result of these phase transitions the structurization of dark matter and therefore the baryon subsystem has taken place. Besides, the role of particle generations in the Universe become more evident. For the possibility of structurization of matter as minimum three generations of particles are necessary.

We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the induction of slow `drifts', oscillating variations and transient-in-time variations of the fundamental constants of Nature by dark matter, which offer a more natural means of producing a cosmological evolution of the fundamental constants compared with traditional dark energy-type theories, which invoke a (nearly) massless underlying field. Thus, measurements of variation of the fundamental constants gives us a new tool in dark matter searches.

The presence of dark matter in the Universe is nowadays widely supported by a large body of astronomical and cosmological observations. One of the best targets to look for dark matter particle self-annihilation into very high energy gamma-rays is the Galactic Center (GC) region. A search for annihilating dark matter in the central 300 parsecs around the GC is performed with the H.E.S.S. array of ground-based Cherenkov telescopes. Using the full H.E.S.S.- I dataset (2004-2014) for this region, new constraints are derived on the velocity-weighted annihilation cross section with a 2D likelihood method, taking advantage of differences in both spectral and spatial morphologies of signal and background. Higher statistics from the 10-years GC dataset of H.E.S.S. I together with a novel analysis technique, allow to improve the present constraints by a factor of 2 for a DM particle mass of 1 TeV. The expected improvement in sensitivity of the new analysis technique, applied to performances of the H.E.S.S.-II array, is also presented.

Dynamical estimates of the mass surface density at the solar radius can be made up to a height of 4 kpc using thick disk stars as tracers of the potential. We investigate why different Jeans estimators of the local surface density lead to puzzling and conflicting results. Using the Jeans equations, we compute the vertical (F_z) and radial (F_R) components of the gravitational force, as well as Gamma(z), defined as the radial derivative of V_c^2, with V_c^{2}= -RF_R. If we assume that the thick disk does not flare and that all the components of the velocity dispersion tensor of the thick disk have a uniform radial scalelength of 3.5 kpc, Gamma takes implausibly large negative values, when using the currently available kinematical data of the thick disk. This implies that the input parameters or the model assumptions must be revised. We have explored, using a simulated thick disk, the impact of the assumption that the scale lengths of the density and velocity dispersions do not depend on the vertical height z above the midplane. In the lack of any information about how these scale radii depend on z, we define a different strategy. By using a parameterized Galactic potential, we find that acceptable fits to F_z, F_R and Gamma are obtained for a flaring thick disk and a spherical dark matter halo with a local density larger than 0.0064 M_sun pc^{-3}. Disk-like dark matter distributions might be also compatible with the current data of the thick disk. A precise measurement of Gamma at the midplane could be very useful to discriminate between models.

As part of the T-REX project, a number of R&D and prototyping activities have been carried out during the last years to explore the applicability of Micromegas-read gaseous TPCs in rare event searches like double beta decay (DBD), axion research and low-mass WIMP searches. While in the companion paper we focus on DBD, in this paper we focus on the results regarding the search for dark matter candidates, both axions and WIMPs. Small ultra-low background Micromegas detectors are used to image the x-ray signal expected in axion helioscopes like CAST at CERN. Background levels as low as $0.8\times 10^{-6}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$ have already been achieved in CAST while values down to $\sim10^{-7}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$ have been obtained in a test bench placed underground in the Laboratorio Subterr\'aneo de Canfranc. Prospects to consolidate and further reduce these values down to $\sim10^{-8}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$will be described. Such detectors, placed at the focal point of x-ray telescopes in the future IAXO experiment, would allow for 10$^5$ better signal-to-noise ratio than CAST, and search for solar axions with $g_{a\gamma}$ down to few 10$^{12}$ GeV$^{-1}$, well into unexplored axion parameter space. In addition, a scaled-up version of these TPCs, properly shielded and placed underground, can be competitive in the search for low-mass WIMPs. The TREX-DM prototype, with $\sim$0.300 kg of Ar at 10 bar, or alternatively $\sim$0.160 kg of Ne at 10 bar, and energy threshold well below 1 keV, has been built to test this concept. We will describe the main technical solutions developed, as well as the results from the commissioning phase on surface. The anticipated sensitivity of this technique might reach $\sim10^{-44}$ cm$^2$ for low mass ($

Although still under debate, observations generally suggest that dwarf spheroidal (dSph) galaxies exhibit large constant-density cores in the centers, which can hardly be explained by dissipationless cold dark matter simulations without baryonic feedback. Wave dark matter (${\psi {\rm DM}}$), characterized by a single parameter, the dark matter particle mass $m_{\psi}$, predicts a central soliton core in every galaxy arising from quantum pressure against gravity. Here we apply Jeans analysis assuming a soliton core profile to the kinematic data of eight classical dSphs so as to constrain $m_{\psi}$, and obtain $m_{\psi}=1.18_{-0.24}^{+0.28}\times10^{-22}{\,\rm eV}$ and $m_{\psi}=1.79_{-0.33}^{+0.35}\times10^{-22}{\,\rm eV}~(2\sigma)$ using the observational data sets of Walker et al. (2007) and Walker et al. (2009b), respectively. We show that the estimate of $m_{\psi}$ is sensitive to the dSphs kinematic data sets and is robust to various models of stellar density profile. We also consider multiple stellar subpopulations in dSphs and find consistent results. This mass range of $m_{\psi}$ is in good agreement with other independent estimates, such as the high-redshift luminosity functions, the reionization history, and the Thomson optical depth to the cosmic microwave background.

We analyse the testability of the type II radiative seesaw in which neutrino mass and dark matter (DM) are related at one-loop level. Under the constraints from DM relic density, direct and indirect detection, and invisible Higgs decays, we find three possible regions of DM mass $M_{s_1}$ that can survive the present and even the future experiments: (1) the Higgs resonance region with $M_{s_1}\sim M_h/2$, (2) the Higgs region with $M_{s_1}\sim M_h$, and (3) the coannihilation region with $M_{s_2}\sim M_{s_1}$. Here $s_{1,2}$ are two scalar singlets with the lighter $s_1$ being the DM candidate. Based on DM properties and direct collider constraints, we choose three benchmark points to illustrate the testability of this model at LHC. We perform a detailed simulation of the four-lepton and tri-lepton signatures at 13 (14) TeV LHC. While both signatures are found to be promising at all benchmark points, the tri-lepton one is even better: it is possible to reach the $5\sigma$ significance with an integrated luminosity of 100/fb.

We propose a novel particle physics model in which vector dark matter (VDM) and dark radiation (DR) originate from the same non-Abelian dark sector. We show an illustrating example where dark $SU(3)$ is spontaneously broken into $SU(2)$ subgroup by the nonzero vacuum expectation value of a complex scalar in fundamental representation of $SU(3)$. The massless gauge bosons associated with the residual unbroken $SU(2)$ constitute DR and help to relieve the tension in Hubble constant measurements between $\textit{Planck}$ and Hubble Space Telescope. In the meantime, massive dark gauge bosons associated with the broken generators are VDM candidates. Intrinsically, this non-Abelian VDM can interact with non-Abelian DR in the cosmic background, which results in a suppressed matter power spectrum and leads to a smaller $\sigma_8$ for structure formation.

In our earlier work on the development of a model-independent data analysis method for reconstructing the (moments of the) time-averaged one-dimensional velocity distribution function of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the reconstruction of the one-dimensional WIMP velocity distribution, the maximal acceptable fraction of residue background events in the analyzed data set(s) of O(500) total events is ~10% - 20%. For a WIMP mass of 50 GeV with a negligible uncertainty and 20% residue background events, the deviation of the reconstructed velocity distribution would in principle be ~7.5% with a statistical uncertainty of ~18% (~19% for a background-free data set).

We demonstrate how the two dominant constituents of the Universe, dark energy and dark matter, could possess a large scattering cross-section without considerably impacting observations. Unlike models involving energy exchange between the two fluids, the background cosmology remains unaltered, leaving fewer observational signatures. Following a brief review of the scattering cross-sections between cosmologically significant particles, we explore the implications of an elastic interaction between dark matter and dark energy. The growth of large scale structure is suppressed, yet this effect is found to be weak due to the persistently low dark energy density. Thus we conclude that the dark matter-dark energy cross section may exceed the Thomson cross-section by several orders of magnitude.

Models of weak-scale supersymmetry offer viable dark matter (DM) candidates. Their parameter spaces are however rather large and complex, such that pinning down the actual parameter values from experimental data can depend strongly on the employed statistical framework and scanning algorithm. In frequentist parameter estimation, a central requirement for properly constructed confidence intervals is that they cover true parameter values, preferably at exactly the stated confidence level when experiments are repeated infinitely many times. Since most widely-used scanning techniques are optimised for Bayesian statistics, one needs to assess their abilities in providing correct confidence intervals in terms of the statistical coverage. Here we investigate this for the Constrained Minimal Supersymmetric Standard Model (CMSSM) when only constrained by data from direct searches for dark matter. We construct confidence intervals from one-dimensional profile likelihoods and study the coverage by generating several pseudo-experiments for a few benchmark sets of pseudo-true parameters. We use nested sampling to scan the parameter space and evaluate the coverage for the benchmarks when either flat or logarithmic priors are imposed on gaugino and scalar mass parameters. The sampling algorithm has been used in the configuration usually adopted for exploration of the Bayesian posterior. We observe both under- and over-coverage, which in some cases vary quite dramatically when benchmarks or priors are modified. We show how most of the variation can be explained as the impact of explicit priors as well as sampling effects, where the latter are indirectly imposed by physicality conditions. For comparison, we also evaluate the coverage for Bayesian credible intervals, and observe significant under-coverage in those cases.

We discuss the dynamics of the universe within the framework of Massive Graviton Dark Matter scenario (MGCDM) in which gravitons are geometrically treated as massive particles. In this modified gravity theory, the main effect of the gravitons is to alter the density evolution of the cold dark matter component in such a way that the Universe evolves to an accelerating expanding regime, as presently observed. Tight constraints on the main cosmological parameters of the MGCDM model are derived by performing a joint likelihood analysis involving the recent supernovae type Ia data, the Cosmic Microwave Background (CMB) shift parameter and the Baryonic Acoustic Oscillations (BAOs) as traced by the Sloan Digital Sky Survey (SDSS) red luminous galaxies. The linear evolution of small density fluctuations is also analysed in detail. It is found that the growth factor of the MGCDM model is slightly different ($\sim1-4%$) from the one provided by the conventional flat $\Lambda$CDM cosmology. The growth rate of clustering predicted by MGCDM and $\Lambda$CDM models are confronted to the observations and the corresponding best fit values of the growth index ($\gamma$) are also determined. By using the expectations of realistic future X-ray and Sunyaev-Zeldovich cluster surveys we derive the dark-matter halo mass function and the corresponding redshift distribution of cluster-size halos for the MGCDM model. Finally, we also show that the Hubble flow differences between the MGCDM and the $\Lambda$CDM models provide a halo redshift distribution departing significantly from the ones predicted by other DE models. These results suggest that the MGCDM model can observationally be distinguished from $\Lambda$CDM and also from a large number of dark energy models recently proposed in the literature.

An analytical model is developed for the mass function of cold dark matter subhalos at the time of accretion and for the distribution of their accretion times. Our model is based on the model of Zhao et al. (2009) for the median assembly histories of dark matter halos, combined with a simple log-normal distribution to describe the scatter in the main-branch mass at a given time for halos of the same final mass. Our model is simple, and can be used to predict the un-evolved subhalo mass function, the mass function of subhalos accreted at a given time, the accretion-time distribution of subhalos of a given initial mass, and the frequency of major mergers as a function of time. We test our model using high-resolution cosmological $N$-body simulations, and find that our model predictions match the simulation results remarkably well. Finally, we discuss the implications of our model for the evolution of subhalos in their hosts and for the construction of a self-consistent model to link galaxies and dark matter halos at different cosmic times.

We consider the infall of a massive clump into a dark-matter halo as a simple and extreme model for the effect of baryonic physics (neglected in gravity-only simulations of large-scale structure formation) on the dark-matter. We find that such an infalling clump is extremely efficient in altering the structure of the halo and reducing its central density: a clump of 1% the mass of the halo can remove about twice its own mass from the inner halo and transform a cusp into a core or weaker cusp. If the clump is subsequently removed, mimicking a galactic wind, the central halo density is further reduced and the mass removed from the inner halo doubled. Lighter clumps are even more efficient: the ratio of removed mass to clump mass increases slightly towards smaller clump masses. This process is the more efficient the more radially anisotropic the initial dark-matter velocities. While such a clumpy infall may be somewhat unrealistic, it demonstrates that the baryons need to transfer only a small fraction of their initial energy to the dark matter via dynamical friction to explain the discrepancy between predicted dark-matter density profiles and those inferred from observations of dark-matter dominated galaxies.

We demonstrate that all properties of the hot X-ray emitting gas in galaxy clusters are completely determined by the underlying dark matter (DM) structure. Apart from the standard conditions of spherical symmetry and hydrostatic equilibrium for the gas, our proof is based on the Jeans equation for the DM and two simple relations which have recently emerged from numerical simulations: the equality of the gas and DM temperatures, and the almost linear relation between the DM velocity anisotropy profile and its density slope. For DM distributions described by the NFW or the Sersic profiles, the resulting gas density profile, the gas-to-total-mass ratio profile, and the entropy profile are all in good agreement with X-ray observations. All these profiles are derived using zero free parameters. Our result allows us to predict the X-ray luminosity profile of a cluster in terms of its DM content alone. As a consequence, a new strategy becomes available to constrain the DM morphology in galaxy clusters from X-ray observations. Our results can also be used as a practical tool for creating initial conditions for realistic cosmological structures to be used in numerical simulations.

We study the nonlinear growth of cosmic structure in different dark energy models, using large volume N-body simulations. We consider a range of quintessence models which feature both rapidly and slowly varying dark energy equations of state, and compare the growth of structure to that in a universe with a cosmological constant. The adoption of a quintessence model changes the expansion history of the universe, the form of the linear theory power spectrum and can alter key observables, such as the horizon scale and the distance to last scattering. We incorporate these effects into our simulations in stages to isolate the impact of each on the growth of structure. The difference in structure formation can be explained to first order by the difference in growth factor at a given epoch; this scaling also accounts for the nonlinear growth at the 15% level. We find that quintessence models that are different from $\Lambda$CDM both today and at high redshifts $(z \sim 1000)$ and which feature late $(z 0$ compared to $\Lambda$CDM and so measurements of the mass function should allow us to distinguish these quintessence models from a cosmological constant. However, we find that a second class of quintessence models, whose equation of state makes an early $(z>2)$ rapid transition to $w=-1$, cannot be distinguished from $\Lambda$CDM using measurements of the mass function or the BAO, even if these models have non-negligible amounts of dark energy at early times.

A dark matter model which is called w-matter or mirror dark matter is concretely constructed based on (f-SU(5))X(w-SU(5)) symmetry. There is no Higgs field and all masses originate from interactions in the present model. W-matter is dark matter relatively to f-matter and vice versa. In high-energy processes or when temperature is very high, visible matter and dark matter can transform from one into another. In such process energy seems to be non-conservational, because dark matter cannot be detected. In low-energy processes or when temperature is low, there is only gravitation interaction of dark matter for visible matter.

The inert higgs model is a minimal extension of the Standard Model that features a viable dark matter candidate, the so-called inert higgs ($H^0$). In this paper, we compute and analyze the dominant electroweak corrections to the direct detection cross section of dark matter within this model. These corrections arise from one-loop diagrams mediated by gauge bosons that, contrary to the tree-level result, do not depend on the unknown scalar coupling $\lambda$. We study in detail these contributions and show that they can modify in a significant way the prediction of the spin-independent direct detection cross section. In both viable regimes of the model, $\mh

We investigate dark matter in a constrained $E_6$ inspired supersymmetric model with an exact custodial symmetry and compare with the CMSSM. The breakdown of $E_6$ leads to an additional $U(1)_N$ symmetry and a discrete matter parity. The custodial and matter symmetries imply there are two stable dark matter candidates, though one may be extremely light and contribute negligibly to the relic density. We demonstrate that a predominantly Higgsino, or mixed bino-Higgsino, neutralino can account for all of the relic abundance of dark matter, while fitting a 125 GeV SM-like Higgs and evading LHC limits on new states. However we show that the recent LUX 2016 limit on direct detection places severe constraints on the mixed bino-Higgsino scenarios that explain all of the dark matter. Nonetheless we still reveal interesting scenarios where the gluino, neutralino and chargino are light and discoverable at the LHC, but the full relic abundance is not accounted for. At the same time we also show that there is a huge volume of parameter space, with a predominantly Higgsino dark matter candidate that explains all the relic abundance, that will be discoverable with XENON1T. Finally we demonstrate that for the $E_6$ inspired model the exotic leptoquarks could still be light and within range of future LHC searches.

Primordial inflation and Dark Matter (DM) could both belong to the hidden sector. It is therefore plausible that the inflaton, which drives inflation, could couple to the DM either directly or indirectly, thus providing a common origin for both luminous and non-luminous matter. We explore this interesting possibility and show that, in certain scenarios, the DM mass can be correlated with the tensor-to-scalar ratio. This correlation might provide us with a window of opportunity for unravelling the properties of DM beyond the standard freeze-out paradigm.