scholarly journals Large scalar multiplet dark matter in the high-mass region

2017 ◽  
Vol 96 (1) ◽  
Author(s):  
Heather E. Logan ◽  
Terry Pilkington
Keyword(s):  
Dark Matter ◽  
Mass Region ◽  
High Mass ◽  
High Mass Region

scholarly journals Bounds on dark matter annihilation cross-sections from inert doublet model in the context of 21-cm cosmology of dark ages

2021 ◽  
pp. 2150163
Author(s):  
Rupa Basu ◽  
Madhurima Pandey ◽  
Debasish Majumdar ◽  
Shibaji Banerjee
Keyword(s):  
Dark Matter ◽  
Cross Sections ◽  
Mass Range ◽  
Mass Region ◽  
High Mass ◽  
Dark Matter Annihilation ◽  
Dark Ages ◽  
Doublet Model ◽  
Inert Doublet Model ◽  
Text Signal

We study the fluctuations in the brightness temperature of 21-cm signal [Formula: see text] at the dark ages ([Formula: see text]) with a dark matter (DM) candidate in Inert Doublet Model (IDM). We then explore the effects of different fractions of IDM DM on [Formula: see text] signal. The IDM DM masses are chosen in few tens of GeV region as well as in the high mass region beyond 500 GeV. It has been observed that the [Formula: see text] signal is more sensitive in the DM mass range of 70–80 GeV. A lower bound on annihilation cross-section for this DM is also obtained by analyzing the [Formula: see text] signal. This is found to lie within the range [Formula: see text] cm3/s for the IDM DM mass range 10 GeV[Formula: see text] GeV.

scholarly journals SEARCHING FOR THE QUARK–DIQUARK SYSTEMATICS OF BARYONS COMPOSED BY LIGHT QUARKS q = u, d

2010 ◽  
Vol 25 (15) ◽  
pp. 2965-2995 ◽  
Author(s):  
A. V. ANISOVICH ◽  
V. V. ANISOVICH ◽  
M. A. MATVEEV ◽  
V. A. NIKONOV ◽  
A. V. SARANTSEV ◽  
...  
Keyword(s):  
Axial Vector ◽  
Mass Region ◽  
High Mass ◽  
Vector State ◽  
Double Pole ◽  
High Mass Region ◽  
Pole Structure ◽  
State Formula ◽  
Baryon Resonances

Supposing quark–diquark structure of baryons, we look for systematics of baryons composed of light quarks (q = u, d). We systematize baryons using the notion of two diquarks: (i) axial–vector state, [Formula: see text], with the spin SD = 1 and isospin ID = 1 and (ii) scalar one, [Formula: see text], with the spin SD = 0 and isospin ID = 0. We consider several schemes for the composed baryons: (1) with different diquark masses, [Formula: see text], (2) with [Formula: see text] and overlapping [Formula: see text] and [Formula: see text] states (resonances), (3) with/without SU(6) constraints for low-lying states (with quark–diquark orbital momenta L = 0). In the high-mass region, the model predicts several baryon resonances at M ~ 2.0–2.9 GeV . Moreover, the model gives us the double pole structure (i.e. two poles with the same Re M but different Im M) in many amplitudes at masses M ≳ 2.0 GeV . We see also that for description of low-lying baryons (with L = 0), the SU(6) constraint is needed.

scholarly journals The formation of ultradiffuse galaxies in the RomulusC galaxy cluster simulation

2020 ◽  
Vol 497 (3) ◽  
pp. 2786-2810 ◽  
Author(s):  
M Tremmel ◽  
A C Wright ◽  
A M Brooks ◽  
F Munshi ◽  
D Nagai ◽  
...  
Keyword(s):  
Dark Matter ◽  
Stellar Evolution ◽  
Dwarf Galaxies ◽  
Galaxy Cluster ◽  
High Mass ◽  
Tidal Interactions ◽  
Low Surface Brightness ◽  
Low Mass ◽  
Tidal Heating ◽  
Low Surface Brightness Galaxies

ABSTRACT We study the origins of 122 ultradiffuse galaxies (UDGs) in the Romulus c zoom-in cosmological simulation of a galaxy cluster (M200 = 1.15 × 1014 M⊙), one of the only such simulations capable of resolving the evolution and structure of dwarf galaxies (M⋆ < 109 M⊙). We find broad agreement with observed cluster UDGs and predict that they are not separate from the overall cluster dwarf population. UDGs in cluster environments form primarily from dwarf galaxies that experienced early cluster in-fall and subsequent quenching due to ram pressure. The ensuing dimming of these dwarf galaxies due to passive stellar evolution results in a population of very low surface brightness galaxies that are otherwise typical dwarfs. UDGs and non-UDGs alike are affected by tidal interactions with the cluster potential. Tidal stripping of dark matter, as well as mass-loss from stellar evolution, results in the adiabatic expansion of stars, particularly in the lowest mass dwarfs. High-mass dwarf galaxies show signatures of tidal heating while low-mass dwarfs that survive until z = 0 typically have not experienced such impulsive interactions. There is little difference between UDGs and non-UDGs in terms of their dark matter haloes, stellar morphology, colours, and location within the cluster. In most respects cluster UDG and non-UDGs alike are similar to isolated dwarf galaxies, except for the fact that they are typically quenched.

scholarly journals Fuzzy dark matter soliton cores around supermassive black holes

2020 ◽  
Vol 492 (4) ◽  
pp. 5721-5729 ◽  
Author(s):  
Elliot Y Davies ◽  
Philip Mocz
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Density Profile ◽  
Mass Region ◽  
Theoretical Modelling ◽  
Black Hole Mass ◽  
Squeezing Effect ◽  
Mass Measurements ◽  
Poisson Equations ◽  
Large Black Hole

ABSTRACT We explore the effect of a supermassive black hole (SMBH) on the density profile of a fuzzy dark matter (FDM) soliton core at the centre of a dark matter (DM) halo. We numerically solve the Schrödinger–Poisson equations, treating the black hole as a gravitational point mass, and demonstrate that this additional perturbing term has a ‘squeezing’ effect on the soliton density profile, decreasing the core radius, and increasing the central density. In the limit of large black hole mass, the solution approaches one akin to the hydrogen atom, with radius inversely proportional to the black hole mass. By applying our analysis to two specific galaxies (M87 and the Milky Way) and pairing it with known observational limits on the amount of centrally concentrated DM, we obtain a constraint on the FDM particle mass, finding that the range 10−22.12 eV ≲ m ≲ 10−22.06 eV should be forbidden (taking into account additional factors concerning the lifetime of the soliton in the vicinity of a black hole). Improved observational mass measurements of the black hole and total enclosed masses will significantly extend the lower bound on the excluded FDM mass region, while self-consistent theoretical modelling of the soliton–black hole system can extend the upper bound.

scholarly journals The Dark Blue Compact Dwarf Galaxy NGC 2915

1997 ◽  
Vol 14 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Gerhardt R. Meurer
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Dwarf Galaxy ◽  
Dark Matter Halo ◽  
High Mass ◽  
Mass Star ◽  
Normal Galaxies ◽  
The Galaxy ◽  
Dark Blue ◽  
Blue Compact Dwarf Galaxy

AbstractRecent results on NGC 2915, the first blue compact dwarf galaxy to have its mass distribution modelled, are summarised. NGC 2915 is shown to have HI well beyond its detected optical extent. Its rotation curve is well determined and fit with maximum disk mass models. The dark matter halo dominates the mass distribution at nearly all radii, and has a very dense core compared to those of normal galaxies. High-mass star formation energises the HI in the centre of the galaxy, but appears to be maintained in viriai equilibrium with the dark matter halo. The implications of these results are briefly discussed.

scholarly journals Studies of the resonance components in the $$B_s$$ decays into charmonia plus kaon pair

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Zhou Rui ◽  
Ya Li ◽  
Hong Li
Keyword(s):  
Mass Spectra ◽  
Branching Ratios ◽  
Mass Region ◽  
Lhcb Collaboration ◽  
High Mass ◽  
Mass Window ◽  
Resonant Structures ◽  
Three Body ◽  
Near Future ◽  
Existing Data

Abstract In this work, the decays of $$B_s$$Bs meson to a charmonium state and a $$K^+K^-$$K+K- pair are carefully investigated in the perturbative QCD approach. Following the latest fit from the LHCb experiment, we restrict ourselves to the case where the produced $$K^+K^-$$K+K- pair interact in isospin zero S, P, and D wave resonances in the kinematically allowed mass window. Besides the dominant contributions of the $$\phi (1020)$$ϕ(1020) resonance in the P-wave and $$f_2'(1525)$$f2′(1525) in the D-wave, other resonant structures in the high mass region as well as the S-wave components are also included. The invariant mass spectra for most of the resonances in the $$B_s\rightarrow J/\psi K^+K^-$$Bs→J/ψK+K- decay are well reproduced. The obtained three-body decay branching ratios can reach the order of $$10^{-4}$$10-4, which seem to be accessible in the near future experiments. The associated polarization fractions of those vector-vector and vector-tensor modes are also predicted, which are compared with the existing data from the LHCb Collaboration.

scholarly journals Red Halos of Galaxies – Reservoirs of Baryonic Dark Matter?

2007 ◽  
Vol 3 (S244) ◽  
pp. 17-25 ◽  
Author(s):  
E. Zackrisson ◽  
N. Bergvall ◽  
C. Flynn ◽  
G. Östlin ◽  
G. Micheva ◽  
...  
Keyword(s):  
Dark Matter ◽  
Stellar Population ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Mass Function ◽  
Initial Mass Function ◽  
High Mass ◽  
Disk Galaxies ◽  
Near Ir ◽  
Baryonic Dark Matter

AbstractDeep optical/near-IR surface photometry of galaxies outside the Local Group have revealed faint and very red halos around objects as diverse as disk galaxies and starbursting dwarf galaxies. The colours of these structures are too extreme to be reconciled with stellar populations similar to those seen in the stellar halos of the Milky Way or M31, and alternative explanations like dust reddening, high metallicities or nebular emission are also disfavoured. A stellar population obeying an extremely bottom-heavy initial mass function (IMF), is on the other hand consistent with all available data. Because of its high mass-to-light ratio, such a population would effectively behave as baryonic dark matter and could account for some of the baryons still missing in the low-redshift Universe. Here, we give an overview of current red halo detections, alternative explanations for the origin of the red colours and ongoing searches for red halos around types of galaxies for which this phenomenon has not yet been reported. A number of potential tests of the bottom-heavy IMF hypothesis are also discussed.

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