Questions tagged [dark-matter]
Questions about astrophysical observations, experimental searches, and theoretical models related to dark matter and its quanta.
946 questions
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Dark matter's gravity effect on a galaxy
In a galaxy if the vast majority of the dark matter halo is outside the visible normal matter, how does it pull that normal matter in and allow it to spin faster than it would if there was no dark ...
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Can dark matter interactions create detectable shockwaves in galaxy clusters?
Suppose dark matter has weak but non-negligible self-interactions. Could colliding clusters generate pressure-like shocks in the dark sector? If so, how would these affect gravitational lensing? I'd ...
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Observational Challenge to ΛCDM: Why Lensing Centers Ignore Baryons?
In merging galaxy clusters like the Bullet Cluster and Abell 520, spacetime curvature (from lensing) aligns exclusively with dark matter (from non-lensing)—even when baryons dominate the mass and are ...
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Is there an experiment (or a bunch of experiments) that would disprove particle dark matter?
Particle dark matter is a hypothetical substance that is posited to explain the observed stronger acceleration of the stars in galaxies than visible matter could account for. It means adding so-far-...
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Have galaxies had enough time to reach rotational equilibrium? [closed]
Current cosmology explains the anomalous galactic rotation curves by introducing dark matter—an unseen mass that adds gravitational pull, because stars orbit the galactic center faster than expected ...
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If dark matter and dark energy make up most of the universe, why haven’t we been able to detect them directly yet?
If dark matter and dark energy make up most of the universe, why haven’t we been able to detect them directly yet? And what does detecting "directly" even mean?
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Is a density-dependent scalar coupling thermodynamically consistent with the Generalized Second Law in cosmology?
I’m modeling dark matter decay into dark energy via a density-dependent scalar coupling λ_eff(χ). Once χ drops below a threshold, the coupling shuts off to stabilize dark energy density. Is such a ...
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Could dark matter exist outside our flow of time? [closed]
Could dark matter be a form of matter that exists outside our flow of time?*
I've been thinking about the invisibility of dark matter and the fact that it doesn't interact with photons. What if the ...
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EFT operators and RG running
Consider the following pair of EFT operators: $\bar{\chi} \chi \, \bar{q} q$ and $\bar{\chi} \chi \, G^a_{\mu\nu} G^{\mu \nu\,a}$, where $q$ is a SM quark, $G^{\mu \nu\,a}$ is the QCD gauge field, and ...
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Would it be bad if dark matter interacted too weakly? [closed]
There is a plethora of DM (dark matter) models out there, and by no means do all of them include the features of:
Interaction with SM sector via gauge couplings
Self-interaction induced by gauge ...
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What is the opinion of scientific community on mirror particles? [closed]
I have recently been gifted a book about relativistic quantum mechanics that has an extensive discussion of mirror particles (the author is A.V.Andreev in case anyone is interested). Now I like how it ...
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Why does a simulated binary system orbiting in a distribution of particles decrease its internal orbital period?
I performed an N-body simulation of a binary system ($m_1 = 0.3 M_\odot$, $m_2 = 1.3 M_\odot$, $e = 0$, $T_\text{orb} = 10 \,\text{yr}$) on a circular orbit around the center of a Plummer's ...
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Does the Dark Matter Fraction Influence Gravitational Lensing Strength for a Fixed Total Mass?
In the standard ΛCDM framework, gravitational lensing is understood to depend on the total mass distribution along the line of sight, regardless of whether that mass is baryonic or dark. However, in ...
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Does the value of the gravitational constant change due to dark matter? [closed]
Dark matter possesses its own gravity. So wouldn't it mean that we will obtain different values of the gravitational constant by doing experiments at different places?
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Dark matter freeze-out in the Early Universe
Let us consider an Early Universe scenario in which I have dark matter particles (DM) $\chi_1$ and $\chi_2$, with a small mass splliting $\delta \ (m_2 = m_1 + \delta, \quad \delta \ll m_1, m_2)$, ...
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