Detectability of dark matter subhalo impacts in Milky Way stellar streams

The Open Journal of Astrophysics · 2026-01-16

Stellar streams are a promising way to probe the gravitational effects of low-mass dark matter (DM) subhalos. In recent years, there has been a remarkable explosion in the number of stellar streams detected in the Milky Way, and hundreds more may be discovered with future surveys such as LSST. Studies of DM subhalo impacts on streams have so far focused on a few of the thinnest and brightest streams, and it is not known how much information can be gained from the others. In this work, we develop a method to quickly estimate the minimum detectable DM subhalo mass of a given stream, depending on its width, length, distance, and stellar density. We use an analytic model for the impacts and apply a test statistic to determine whether they are detectable. We consider several observational scenarios, based on current and future surveys including , DESI, Via, and LSST. We find that at 95% confidence level, a stream like GD-1 has a minimum detectable subhalo mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>6</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> <mml:mspace width="0.222em"/> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:math> in data and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>8</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>5</mml:mn> </mml:msup> <mml:mspace width="0.222em"/> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:math> with LSST 10 year sensitivity. Applying our results to confirmed Milky Way streams, we rank order them by their sensitivity to DM subhalos and identify promising ones for further study.

Spin-dependent scattering of sub-GeV dark matter: Models and constraints

Physical review. D/Physical review. D. · 2025-09-15 · 2 citations

We calculate the scattering rate of sub-GeV dark matter in solid-state targets for spin-dependent dark matter–nucleon interactions. For dark matter particles with mass below 100 MeV, the scattering occurs predominantly through incoherent phonon production. For dark matter heavier than 100 MeV, we match onto the nuclear recoil calculation. To compare the sensitivity of future direct detection experiments with existing constraints, we consider three models with interactions that are mediated by spin-0 or spin-1 particles. This allows us to derive bounds on the cross section from searches for the mediating particle, including bounds from stellar cooling, beam dump experiments, meson factories, and dark matter self-interactions. The existing bounds are very stringent, though for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mi>m</a:mi> <a:mi>χ</a:mi> </a:msub> <a:mo>≳</a:mo> <a:mn>100</a:mn> <a:mtext> </a:mtext> <a:mtext> </a:mtext> <a:mi>MeV</a:mi> </a:math> there is parameter space, which may be accessible with direct detection, depending on the exposure and background rates.

Spin-Dependent Scattering of Sub-GeV Dark Matter: Models and Constraints

ArXiv.org · 2025-06-12

We calculate the scattering rate of sub-GeV dark matter in solid-state targets for spin-dependent dark matter -- nucleon interactions. For dark matter particles with mass below 100 MeV, the scattering occurs predominantly through incoherent phonon production. For dark matter heavier than 100 MeV, we match onto the nuclear recoil calculation. To compare the sensitivity of future direct detection experiments with existing constraints, we consider three models with interactions which are mediated by spin-0 or spin-1 particles. This allows us to derive bounds on the cross section from searches for the mediating particle, including bounds from stellar cooling, beam dump experiments, meson factories and dark matter self-interactions. The existing bounds are very stringent, though for $m_χ\gtrsim 100$ MeV there is parameter space which may be accessible with direct detection, depending on the exposure and background rates.

Daily modulation of low-energy nuclear recoils from sub-GeV dark matter

Physical review. D/Physical review. D. · 2025-02-12 · 2 citations

At sufficiently low nuclear recoil energy, the scattering of dark matter (DM) in crystals gives rise to single phonon and multiphonon excitations. In anisotropic crystals, the scattering rate into phonons modulates over each sidereal day as the crystal rotates with respect to the DM wind. This gives a potential avenue for directional detection of DM. The daily modulation for single phonons has previously been calculated. Here we calculate the daily modulation for multiphonon excitations from DM in the mass range 1 MeV–1 GeV. We generalize previous multiphonon calculations, which made an isotropic approximation, and implement results in the DarkELF package. We find daily modulation rates up to 1%–10% for an <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi>Al</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi mathvariant="normal">O</a:mi><a:mn>3</a:mn></a:msub></a:math> target and DM mass below 30 MeV, depending on the recoil energies probed. We obtain similar results for SiC, while modulation in Si, GaAs, and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:msub><d:mrow><d:mi>SiO</d:mi></d:mrow><d:mrow><d:mn>2</d:mn></d:mrow></d:msub></d:mrow></d:math> is negligible.

Listening for new physics with quantum acoustics

Physical review. D/Physical review. D. · 2025-10-01 · 1 citations

We present a novel application of a qubit-coupled phonon detector to search for new physics, e.g., ultralight dark matter (DM) and high-frequency gravitational waves. The detector, motivated by recent advances in quantum acoustics, is composed of superconducting transmon qubits coupled to high-overtone bulk acoustic resonators ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mi>h</a:mi> <a:mi>BARs</a:mi> </a:mrow> </a:math> ) and operates in the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mrow> <c:mtext> </c:mtext> <c:mi>GHz</c:mi> <c:mo>−</c:mo> <c:mn>10</c:mn> <c:mtext> </c:mtext> <c:mtext> </c:mtext> <c:mi>GHz</c:mi> </c:mrow> </c:math> frequency range. New physics can excite <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi mathvariant="script">O</e:mi> <e:mo stretchy="false">(</e:mo> <e:mn>10</e:mn> <e:mtext> </e:mtext> <e:mtext> </e:mtext> <e:mi mathvariant="normal">μ</e:mi> <e:mi>eV</e:mi> <e:mo stretchy="false">)</e:mo> </e:math> phonons within the <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>h</k:mi> <k:mi>BAR</k:mi> </k:math> , which are then converted to qubit excitations via a transducer. We detail the design, operation, backgrounds, and expected sensitivity of a prototype detector, as well as a next-generation detector optimized for new physics signals. We find that a future detector can complement current haloscope experiments in the search for both dark photon DM and high-frequency gravitational waves. Lastly, we comment on such a detector’s ability to operate as a <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mrow> <m:mi mathvariant="script">O</m:mi> <m:mo stretchy="false">(</m:mo> <m:mn>10</m:mn> <m:mtext> </m:mtext> <m:mtext> </m:mtext> <m:mi mathvariant="normal">μ</m:mi> <m:mi>eV</m:mi> <m:mo stretchy="false">)</m:mo> </m:mrow> </m:math> athermal phonon sensor for sub-GeV DM detection.

The Escape Velocity Profile of the Milky Way from Gaia DR3

arXiv (Cornell University) · 2024-01-31

The escape velocity profile of the Milky Way offers a crucial and independent measurement of its underlying mass distribution and dark matter properties. Using a sample of stars from Gaia DR3 with 6D kinematics and strict quality cuts, we obtain an escape velocity profile of the Milky Way from 4 kpc to 11 kpc in Galactocentric radius. To infer the escape velocity in radial bins, we model the tail of the stellar speed distribution with both traditional power law models and a new functional form that we introduce. While power law models tend to rely on extrapolation to high speeds, we find our new functional form gives the most faithful representation of the observed distribution. Using this for the escape velocity profile, we constrain the properties of the Milky Way's dark matter halo modeled as a Navarro-Frenck-White profile. Combined with constraints from the circular velocity at the solar position, we obtain a concentration and mass of $c_{200\rm{c}}^{\rm{DM}} = 13.9^{+6.2}_{-4.3}$ and $\rm{M}_{200\rm{c}}^{\rm{DM}} = 0.55^{+0.15}_{-0.14}\times 10^{12} M_\odot$. This corresponds to a total Milky Way mass of $\rm{M}_{200\rm{c}} = 0.64^{+0.15}_{-0.14}\times 10^{12} M_\odot$, which is on the low end of the historic range of the Galaxy's mass, but in line with other recent estimates.

Anharmonic effects in nuclear recoils from sub-GeV dark matter

Physical review. D/Physical review. D. · 2024-05-14 · 4 citations

Direct detection experiments are looking for nuclear recoils from scattering of sub-GeV dark matter (DM) in crystals, and have thresholds as low as <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo>∼</a:mo><a:mn>10</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>eV</a:mi></a:mrow></a:math> or DM masses of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mo>∼</c:mo><c:mn>100</c:mn><c:mtext> </c:mtext><c:mtext> </c:mtext><c:mi>MeV</c:mi></c:math>. Future experiments are aiming for even lower thresholds. At such low energies, the free nuclear recoil prescription breaks down, and the relevant final states are phonons in the crystal. Scattering rates into single as well as multiple phonons have already been computed for a harmonic crystal. However, crystals typically exhibit some anharmonicity, which can significantly impact scattering rates in certain kinematic regimes. In this work, we estimate the impact of anharmonic effects on scattering rates for DM in the mass range <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mo>∼</e:mo><e:mn>1</e:mn><e:mi>–</e:mi><e:mn>10</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>MeV</e:mi></e:math>, where the details of multiphonon production are most important. Using a simple model of a nucleus in a bound potential, we find that anharmonicity can modify the scattering rates by up to two orders of magnitude for DM masses of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi mathvariant="script">O</g:mi><g:mo stretchy="false">(</g:mo><g:mi>MeV</g:mi><g:mo stretchy="false">)</g:mo></g:math>. However, such effects are primarily present at high energies where the rates are suppressed, and thus only relevant for very large DM cross sections. We show that anharmonic effects are negligible for masses larger than <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:mo>∼</l:mo><l:mn>10</l:mn><l:mtext> </l:mtext><l:mtext> </l:mtext><l:mi>MeV</l:mi></l:math>. Published by the American Physical Society 2024

Amplitude analysis and branching fraction measurement of $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ decays

Journal of High Energy Physics · 2024 · 1 citations

• Computer Science
• Algorithm
• Physics

A bstract The decays of the B + meson to the final state $$ {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb − 1 . The ratio of branching fractions of the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> and $$ {B}^0\to {D}^{\ast -}{D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>B</mml:mi> <mml:mn>0</mml:mn> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> decays is measured to be 0 . 173 ± 0 . 006 ± 0 . 010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed $$ {D}_s^{\ast +}\to {D}_s^{+}\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> <mml:mo>→</mml:mo> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mi>γ</mml:mi> </mml:math> and $$ {D}_s^{+}{\pi}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> decays, the ratio of branching fractions between the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{\ast +}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> and $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> decays is determined as 1 . 31 ± 0 . 07 ± 0 . 14. An amplitude analysis of the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msup> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D * − π + final state. No significant evidence of exotic contributions in the $$ {D}_s^{+}{\pi}^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> or $$ {D}^{\ast -}{D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo>

The Escape Velocity Profile of the Milky Way from Gaia DR3

The Astrophysical Journal · 2024-08-26 · 13 citations

Abstract The escape velocity profile of the Milky Way offers a crucial and independent measurement of its underlying mass distribution and dark matter (DM) properties. Using a sample of stars from the third data release of Gaia with 6D kinematics and strict quality cuts, we obtain an escape velocity profile of the Milky Way from 4 to 11 kpc in Galactocentric radius. To infer the escape velocity in radial bins, we model the tail of the stellar speed distribution with both traditional power-law models and a new functional form that we introduce. While power-law models tend to rely on extrapolation to high speeds, we find our new functional form gives the most faithful representation of the observed distribution. Using this for the escape velocity profile, we constrain the properties of the Milky Way’s DM halo modeled as a Navarro–Frenck–White profile. Combined with constraints from the circular velocity at the solar position, we obtain a concentration and mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mi>c</mml:mi> <mml:mrow> <mml:mn>200</mml:mn> <mml:mi>c</mml:mi> </mml:mrow> <mml:mi>DM</mml:mi> </mml:msubsup> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mn>13.9</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>6.2</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>200</mml:mn> <mml:mrow> <mml:mi>c</mml:mi> </mml:mrow> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">DM</mml:mi> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.55</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.14</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.15</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>12</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> . This corresponds to a total Milky Way mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>200</mml:mn> <mml:mrow> <mml:mi>c</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.64</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.14</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.15</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>12</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> , which is on the low end of the historic range of the galaxy’s mass, but in line with other recent estimates.

Listening For New Physics With Quantum Acoustics

arXiv (Cornell University) · 2024-10-22

We present a novel application of a qubit-coupled phonon detector to search for new physics, e.g., ultralight dark matter (DM) and high-frequency gravitational waves. The detector, motivated by recent advances in quantum acoustics, is composed of superconducting transmon qubits coupled to high-overtone bulk acoustic resonators ($h$BARs) and operates in the GHz - 10 GHz frequency range. New physics can excite $O(10 \, μ\text{eV})$ phonons within the $h$BAR, which are then converted to qubit excitations via a transducer. We detail the design, operation, backgrounds, and expected sensitivity of a prototype detector, as well as a next-generation detector optimized for new physics signals. We find that a future detector can complement current haloscope experiments in the search for both dark photon DM and high-frequency gravitational waves. Lastly we comment on such a detector's ability to operate as a $10 \, μ\text{eV}$ threshold athermal phonon sensor for sub-GeV DM detection.