scholarly journals Strong constraints from COSINE-100 on the DAMA dark matter results using the same sodium iodide target

2021 ◽  
Author(s):  
Govinda Adhikari ◽  
E. Barbosa de Souza ◽  
N. Carlin ◽  
J.J. Choi ◽  
S. Choi ◽  
...  
Keyword(s):  
Dark Matter ◽  
Sodium Iodide ◽  
Weakly Interacting Massive Particles ◽  
Dark Matter Halo ◽  
Annual Modulation ◽  
Interaction Hypothesis ◽  
Order Of Magnitude ◽  
Modulation Signal ◽  
Alternative Scenarios ◽  
First Time

Abstract It is a long-standing debate as to whether or not the annual modulation in the event rate observed by the DAMA sodium iodide experiment is caused by the interaction of dark matter particles. To resolve this issue, several groups have been working to develop new experiments with the aim of reproducing or refuting DAMA's results using the same sodium iodide target medium. The COSINE-100 experiment is one of these that is currently operating with 106 kg of low-background sodium iodide crystals at the Yangyang underground laboratory. Analysis of the initial 59.5 days of COSINE-100 data showed that the annual modulation signal reported by DAMA is inconsistent with explanation using spin-independent interaction of weakly interacting massive particles (WIMPs), a favored candidate of dark matter particles, with sodium or iodine nuclei in the context of the standard halo mode. However, this first result left open interpretations using certain alternative dark matter models, dark matter halo distributions, and detector responses that could allow room for consistency between DAMA and COSINE-100. Here we present new results from over 1.7 years of COSINE-100 operation with improved event selection and energy threshold reduced from 2 keV to 1 keV. We find an order of magnitude improvement in sensitivity, sufficient for the first time to strongly constrain these alternative scenarios, as well as to further strengthen the previously observed inconsistency with the WIMP-nucleon spin-independent interaction hypothesis.

scholarly journals Structure of Dark Matter Halo

1999 ◽  
Vol 183 ◽  
pp. 155-155
Author(s):  
Toshiyuki Fukushige ◽  
Junichiro Makino
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Temperature Inversion ◽  
Dark Matter Halo ◽  
Temperature Structure ◽  
Galactic Halos ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Order Of Magnitude ◽  
Special Purpose Computer

We performed N-body simulation on special-purpose computer, GRAPE-4, to investigate the structure of dark matter halos (Fukushige, T. and Makino, J. 1997, ApJL, 477, L9). Universal profile proposed by Navarro, Frenk, and White (1996, ApJ, 462, 563), which has cusp with density profiles ρ ∝r−1in density profile, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were based on simulations with relatively few particles, and substantial softening. We performed simulations with particle numbers an order of magnitude higher, and essentially no softening, and found that typical central density profiles are clearly steeper than ρ ∝r−1, as shown in Figure 1. In addition, we confirm the presence of a temperature inversion in the inner 5 kpc of massive galactic halos, and give a natural explanation for formation of the temperature structure.

scholarly journals Detection of a slow H i bar in the dwarf irregular galaxy DDO 168

2019 ◽  
Vol 488 (4) ◽  
pp. 4942-4951
Author(s):  
Narendra Nath Patra ◽  
Chanda J Jog
Keyword(s):  
Dark Matter ◽  
Time Scale ◽  
Dark Matter Halo ◽  
Irregular Galaxy ◽  
Stringent Constraint ◽  
Dynamical Time ◽  
Dimensionless Ratio ◽  
Pattern Speed ◽  
Pattern Speeds ◽  
First Time

Abstract We examine the H i total intensity maps of the VLA LITTLE-THINGS galaxies and identify an H i bar in the dwarf irregular galaxy DDO 168 which has a dense and compact dark matter halo that dominates at all radii. This is only the third galaxy found to host an H i bar. Using the H i kinematic data, we apply the Tremaine–Weinberg method to estimate the pattern speed of the bar. The H i bar is found to have an average pattern speed of 23.3 ± 5.9 $\rm km \, s^{-1} \, kpc^{-1}$. Interestingly, for the first time, we find that the observed pattern speeds of the bar in the two kinematic halves are different. We identify the origin of this difference to be the kinematic asymmetry. This observed offset in the pattern speed serves to put a stringent constraint on the lifetime of the bar set by the winding time-scale. The lifetime of the bar is found to be 5.3 × 108 yr, which is two times the dynamical time-scale of the disc. We also find the H i bar in DDO 168 to be a weak bar with a strength of 0.2. If H i bar being weak can be easily disturbed, this could possibly explain why it is extremely rare to observe H i bars in galaxies. We estimate the bar radius to be 1 kpc and the dimensionless ratio, RL/Rb to be ≥2.1 indicating a ‘slow’ bar in DDO 168. Our results confirm the proposition that the dynamical friction with the halo slows down a rotating bar in a galaxy dominated by dark matter halo from inner radii.

scholarly journals Beyond ΛCDM with H i intensity mapping: robustness of cosmological constraints in the presence of astrophysics

2020 ◽  
Vol 496 (4) ◽  
pp. 4115-4126 ◽  
Author(s):  
Stefano Camera ◽  
Hamsa Padmanabhan
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Cosmological Parameters ◽  
Neutral Hydrogen ◽  
Temperature Fluctuations ◽  
Dark Matter Halo ◽  
Cosmological Constraints ◽  
Intensity Mapping ◽  
Standard Cosmological Model ◽  
First Time

ABSTRACT Mapping the unresolved intensity of the 21-cm emission of neutral hydrogen (H i) is now regarded as one the most promising tools for cosmological investigation in the coming decades. Here, we investigate, for the first time, extensions of the standard cosmological model, such as modified gravity and primordial non-Gaussianity, taking self-consistently into account. The present constraints on the astrophysics of H i clustering in the treatment of the brightness temperature fluctuations. To understand the boundaries within which results thus obtained can be considered reliable, we examine the robustness of cosmological parameter estimation performed via studies of 21-cm intensity mapping, against our knowledge of the astrophysical processes leading to H i clustering. Modelling of astrophysical effects affects cosmological observables through the relation linking the overall H i mass in a bound object, to the mass of the underlying dark matter halo that hosts it. We quantify the biases in estimates of standard cosmological parameters and those describing modified gravity and primordial non-Gaussianity that are obtained if one misconceives the slope of the relation between H i mass and halo mass, or the lower virial velocity cut-off for a dark matter halo to be able to host H i. Remarkably, we find that astrophysical uncertainties will not affect searches for primordial non-Gaussianity – one of the strongest science cases for H i intensity mapping – despite the signal being deeply linked to the H i bias.

scholarly journals First search for a dark matter annual modulation signal with NaI(Tl) in the Southern Hemisphere by DM-Ice17

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
E. Barbosa de Souza ◽  
J. Cherwinka ◽  
A. Cole ◽  
A. C. Ezeribe ◽  
D. Grant ◽  
...  
Keyword(s):  
Dark Matter ◽  
Southern Hemisphere ◽  
Annual Modulation ◽  
Modulation Signal

scholarly journals Analysis of the 40K contamination in NaI(Tl) crystals from different providers in the frame of the ANAIS project

2014 ◽  
Vol 29 (19) ◽  
pp. 1443010 ◽  
Author(s):  
C. Cuesta ◽  
J. Amaré ◽  
S. Cebrián ◽  
E. García ◽  
C. Ginestra ◽  
...  
Keyword(s):  
Dark Matter ◽  
Sodium Iodide ◽  
Low Energy ◽  
Annual Modulation ◽  
Dark Matter Search ◽  
Scintillation Signal ◽  
Nuclear Recoils ◽  
Search Experiment ◽  
Low Efficiency ◽  
Electron Equivalent

NaI(Tl) large crystals are applied in the search for galactic dark matter particles through their elastic scattering off the target nuclei in the detector by measuring the scintillation signal produced. However, energies deposited in the form of nuclear recoils are small, which added to the low efficiency to convert that energy into scintillation, makes that events at or very near the energy threshold, attributed either to radioactive backgrounds or to spurious noise (nonbulk NaI(Tl) scintillation events), can compromise the sensitivity goals of such an experiment. DAMA/LIBRA experiment, using 250 kg NaI(Tl) target, reported first evidence of the presence of an annual modulation in the detection rate compatible with that expected for a dark matter signal just in the region below 6 keVee (electron equivalent energy). In the frame of the ANAIS (Annual modulation with NaI Scintillators) dark matter search project a large and long effort has been carried out in order to understand the origin of events at very low energy in large sodium iodide detectors and develop convenient filters to reject those nonattributable to scintillation in the bulk NaI(Tl) crystal. 40K is probably the most relevant radioactive contaminant in the bulk for NaI(Tl) detectors because of its important contribution to the background at very low energy. ANAIS goal is to achieve levels at or below 20 ppb natural potassium. In this paper we will report on our effort to determine the 40K contamination in several NaI(Tl) crystals, by measuring in coincidence between two (or more) of them. Results obtained for the 40K content of crystals from different providers will be compared and prospects of the ANAIS dark matter search experiment will be briefly reviewed.

scholarly journals Mild Velocity Dispersion Evolution of massive galaxies since z~2

2009 ◽  
Vol 5 (S262) ◽  
pp. 184-187
Author(s):  
Ignacio Trujillo ◽  
A. Javier Cenarro
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Massive Galaxies ◽  
Strong Change ◽  
First Time ◽  
Lower Redshift

AbstractMaking use of public spectra from Cimatti et al. (2008), we measure for the first time the velocity dispersion of spheroid-like massive (M* ~ 1011M⊙) galaxies at z ~ 1.6. By comparing with galaxies of similar stellar mass at lower redshifts, we find evidence for a mild evolution in velocity dispersion, decreasing from ~240 kms−1 at z ~ 1.6 down to ~180 km s−1 at z ~ 0. Such mild evolution contrasts with the strong change in size (a factor of ~4) found for these type of objects in the same cosmic time, and it is consistent with a progressive larger role, at lower redshift, of the dark matter halo in setting the velocity dispersion of these galaxies. We discuss the implications of our results within the context of different scenarios proposed for the evolution of these massive objects.

scholarly journals RECONCILING THE POSITIVE DAMA ANNUAL MODULATION SIGNAL WITH THE NEGATIVE RESULTS OF THE CDMS II EXPERIMENT

2004 ◽  
Vol 19 (24) ◽  
pp. 1841-1846 ◽  
Author(s):  
R. FOOT
Keyword(s):  
Dark Matter ◽  
Positive Result ◽  
Lower Threshold ◽  
Annual Modulation ◽  
Null Results ◽  
Negative Results ◽  
Modulation Signal ◽  
Decisive Test ◽  
Light Target ◽  
Mirror Matter

We examine the recent CDMS II results in the context of the mirror matter interpretation of the DAMA/NaI experiment. We find that the favoured mirror matter interpretation of the DAMA/NaI experiment — a He ′/ H ′-dominated halo with a small O ′ component is fully consistent with the null results reported by CDMS II. While the CDMS II experiment is quite sensitive to a heavy Fe ′ component, and may yet find a positive result, a more decisive test of mirror matter-type dark matter would require a lower threshold experiment using light target elements.

scholarly journals Quantum Theory of Gravity and Arthur Eddingtons Fundamental Theory

2021 ◽  
Vol 2 (11) ◽  
pp. 1092-1100
Author(s):  
Konstantinov SI
Keyword(s):  
Dark Matter ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Dark Matter Halo ◽  
Fundamental Theory ◽  
Theories Of Gravity ◽  
Theory Of Gravity ◽  
First Time ◽  
Contraction And Expansion ◽  
The Universe

For the first time, the article presents the Quantum Theory of Gravity, covering not only the microcosm of elementary particles, but also the macrocosm of planets, stars and black holes. This relational approach to gravity was consistently presented in Arthur Eddington's monograph “Fundamental Theory”. In the theory of quantum gravity proposes to consider instead of gravity holes in the curved space-time of Einstein's general relativity, gravitational funnels formed by the rotation of planets, stars and galaxies in a dark matter halo. The change in the gravitational potential in the funnels occurs instantly in all areas of the gravitational funnel space in accordance with the pressure gradient described by the Euler-Bernoulli equation for superfluid continuous media. The new cosmological theory represents the evolution of the universe and dark holes without a singularity. The disordered alternation of the processes of contraction and expansion of individual regions of the infinite Universe realizes the circulation of baryonic and dark matter, which allows it to exist indefinitely, bypassing the state of equilibrium. Numerical modeling allows us to assert that the theory of quantum gravity is the most reliable of the three generally accepted theories of gravity.

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