We probe dark matter-electron scattering using high-energy neutrino observations from the Sun. Dark matter (DM) interacting with electrons can get captured inside the Sun. These captured DM may annihilate to produce different Standard Model (SM) particles. Neutrinos produced from these SM states can be observed in IceCube and DeepCore. Although there is no excess of neutrinos in the solar direction, we find that the current datasets of IceCube and DeepCore set the strongest constraint on the DM-electron scattering cross section in the DM mass range 10–<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mn>5</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. Therefore our work implies that future observations of the Sun by neutrino telescopes have the potential to discover the DM-electron interaction.

India

Australia

Tarak Nath Maity

Akash Kumar Saha

Sagnik Mondal

Ranjan Laha

Neutrinos from the Sun can discover dark matter-electron scattering

The solar steady emission in gamma rays is due to the interactions of Galactic cosmic rays with the solar atmosphere and with the low-energy solar photon field via inverse Compton scattering. The emission is sensitive to the magnetic field nearby the Sun and to the cosmic-ray transport in the magnetic field in the inner Solar System. Modeling the inverse Compton emission in the presence of a magnetic field is, therefore, crucial to better interpret the observations. In a previous work, we have presented a comprehensive calculation of the secondary productions due to the collision of cosmic rays with the solar atmosphere in the presence of magnetic fields. In this paper, we present a general approach to calculate the (anisotropic) inverse Compton scattering in a 3D Monte Carlo simulation, also in the presence of magnetic and electric fields. After a short review of the scattering process of photons with electrons, examples of inverse Compton emission are presented, including the predictions for the Sun.

Italy

M.N. Mazziotta

3D Monte Carlo calculation of the inverse Compton emission from the Sun and stars in the presence of magnetic and electric fields

The discovery of solar neutrinos confirmed that the inner workings of the Sun generally match our theoretical understanding of the fusion process. Solar neutrinos have also played a role in discovering that neutrinos have mass and that they oscillate. We combine the latest solar neutrino data along with other oscillation data from reactors to determine the Sun's density profile. We derive constraints given the current data and show the anticipated improvements with more reactor neutrino data from JUNO constraining the true oscillation parameters and more solar neutrino data from DUNE which should provide a crucial measurement of <italic>hep</italic> neutrinos.

United States

Peter B. Denton

Charles Gourley

Determining the density of the sun with neutrinos

In this study, we investigate the $R^2$ corrections to the dissociation of heavy quarkonium in the Gauss-Bonnet gravitational background. We analyze the impact of the Gauss-Bonnet parameter $\lambda_{\rm GB}$ on the spectral function of charmonium and bottomonium and examine the effect of $\lambda_{\rm GB}$ on the dissociation of heavy quarkonium. Our results show that $\lambda_{\rm GB}$ reduces the peak height and increases the peak width of the spectral function, suggesting that $\lambda_{\rm GB}$ enhances the dissociation of heavy quarkonium. We also discuss the variation in the dissociation of heavy quarkonium with the ratio of shear viscosity to entropy density and observe that the dissociation is easier in more perfect plasma. Additionally, we observe that the temperature decreases the peak height and widens the peak, thereby accelerating the dissociation.

China

Zhou-Run Zhu

Manman Sun

Rui Zhou

Jinzhong Han

$\textit{R}$ $^{2}$ corrections to holographic heavy quarkonium dissociation * Rui Zhou supported by the Science and Technology Development Plan Project of Henan Province, China (242102230085), the National Natural Science Foundation of China (12404470), the High Level Talents Research and Startup Foundation Projects for Doctors of Zhoukou Normal University, China (ZKNUC2023017). Manman Sun supported by the National Natural Science Foundation of China (12305076). Zhou-Run Zhu supported by the High Level Talents Research and Startup Foundation Projects for Doctors of Zhoukou Normal University, China (ZKNUC2023018)

The Sun is not quite a perfect sphere, and its oblateness, thought to be induced through its rotation, has been measured using optical observations of its radius. Its gravitational quadrupole moment can then be deduced using solar models, or through helioseismology, and it can also be determined from measurements of its gravitational effects on Mercury’s orbit. The various assessments do not appear to agree, with the most complete and precise orbital assessments being in slight excess of other determinations. This may speak to the existence of a nonluminous disk or ring, where we also note evidence for a circumsolar dust ring within Mercury’s orbit from the Solar TErrestrial RElations Observatory (STEREO) mission. Historically, too, a protoplanetary disk may have been key to reconciling the Sun’s metallicity with its neutrino yield. The distribution of the nonluminous mass within Mercury’s orbit can modify the relative size of the optical and orbital quadrupole moments in different ways. We develop how we can use these findings to limit the mass of a dark disk, ring, or halo in the immediate vicinity of the Sun, and we note how future observational studies of the inner Solar System can not only refine these constraints but can also help to identify and to assess the mass of its dark-matter component.

Brazil

Gustavo F.S. Alves

Susan Gardner

Pedro Machado

Mohammadreza Zakeri

Does the Sun have a dark disk?

Millicharged dark matter particles can be efficiently captured by the Sun, where they annihilate into tau leptons, leading to the production of high-energy neutrinos. In contrast to the Earth, the high temperature of the Sun suppresses the fraction of millicharged particles that are bound to nuclei, allowing for potentially high annihilation rates. We recast existing constraints from the IceCube Neutrino Observatory and use this information to place new limits on the fraction of the dark matter that is millicharged. This analysis excludes previously unexplored parameter space for masses of <math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>χ</mi></mrow></msub><mo>∼</mo><mo>(</mo><mn>5</mn><mi>–</mi><mn>100</mn><mo>)</mo><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>, charges of <math><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>χ</mi></mrow></msub><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup><mi>–</mi><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math>, and fractional abundances as small as <math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>DM</mi></mrow></msub><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math>.

Asher Berlin

Dan Hooper

High-energy neutrinos from millicharged dark matter annihilation in the Sun

The exploration of the parameter space of axion and axion-like particle dark matter is a major aim of the future program of astroparticle physics investigations. In this context, we present a possible strategy that focuses on detecting radio emissions arising from the conversion of dark matter axions in the Sun's magnetic field, including conversion in sunspots. We demonstrate that near-future low-frequency radio telescopes, such as the SKA Low, may access regions of unexplored parameter space for masses <math><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>≲</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></math> eV.

Elisa Todarello

Marco Regis

Marco Taoso

Spain

Maurizio Giannotti

Jaime Ruz

Julia K. Vogel

The Sun as a target for axion dark matter detection

The Sun may capture asymmetric dark matter (DM), which can subsequently form bound-states through the radiative emission of a sub-GeV scalar. This process enables generation of scalars without requiring DM annihilation. In addition to DM capture on nucleons, the DM-scalar coupling responsible for bound-state formation also induces capture from self-scatterings of ambient DM particles with DM particles already captured, as well as with DM bound-states formed in-situ within the Sun. This scenario is studied in detail by solving Boltzmann equations numerically and analytically. In particular, we take into consideration that the DM self-capture rates require a treatment beyond the conventional Born approximation. We show that, thanks to DM scatterings on bound-states, the number of DM particles captured increases exponentially, leading to enhanced emission of relativistic scalars through bound-state formation, whose final decay products could be observable. We explore phenomenological signatures with the example that the scalar mediator decays to neutrinos. We find that the neutrino flux emitted can be comparable to atmospheric neutrino fluxes within the range of energies below one hundred MeV. Future facilities like Hyper-K, and direct DM detection experiments can further test such scenario.

Austria

Xiaoyong Chu

Raghuveer Garani

Camilo García-Cely

CERN

Belgium

Thomas Hambye

Dark matter bound-state formation in the Sun

The nuclear reaction network within the interior of the Sun is an efficient MeV physics factory and can produce long-lived particles generic to dark sector models. In this work we consider the sensitivity of satellite instruments, primarily the RHESSI spectrometer, that observe the quiet Sun in the MeV regime where backgrounds are low. We find that quiet Sun observations offer a powerful and complementary probe in regions of parameter space, where the long-lived particle decay length is longer than the radius of the Sun and shorter than the distance between the Sun and Earth. We comment on connections to recent model-building work on heavy neutral leptons coupled to neutrinos and high-quality axions from mirror symmetries.

R. Andrew Gustafson

Ryan Plestid

Ian M. Shoemaker

Germany

Albert Zhou

Long-lived particles and the quiet Sun

This article reports the first observation of the Moon and the Sun shadows in the sky distribution of cosmic-ray induced muons measured by the KM3NeT/ORCA detector. The analysed data-taking period spans from February 2020 to November 2021, when the detector had 6 Detection Units deployed at the bottom of the Mediterranean Sea, each composed of 18 Digital Optical Modules. The shadows induced by the Moon and the Sun were detected at their nominal position with a statistical significance of 4.2 $$\sigma $$ <math> <mi>σ</mi> </math> and 6.2 $$\sigma $$ <math> <mi>σ</mi> </math> , and an angular resolution of $$\sigma _{res}=0.49^\circ $$ <math> <mrow> <msub> <mi>σ</mi> <mrow> <mi>res</mi> </mrow> </msub> <mo>=</mo> <mn>0</mn> <mo>.</mo> <msup> <mn>49</mn> <mo>∘</mo> </msup> </mrow> </math> and $$\sigma _{res}=0.66^\circ $$ <math> <mrow> <msub> <mi>σ</mi> <mrow> <mi>res</mi> </mrow> </msub> <mo>=</mo> <mn>0</mn> <mo>.</mo> <msup> <mn>66</mn> <mo>∘</mo> </msup> </mrow> </math> , respectively, consistent with the prediction of $$0.53^\circ $$ <math> <mrow> <mn>0</mn> <mo>.</mo> <msup> <mn>53</mn> <mo>∘</mo> </msup> </mrow> </math> from simulations. This early result confirms the effectiveness of the detector calibration, in time, position and orientation and the accuracy of the event direction reconstruction. This also demonstrates the performance and the competitiveness of the detector in terms of pointing accuracy and angular resolution.

S. Aiello

France

A. Albert

S. Alves Garre

Z. Aly

A. Ambrosone

F. Ameli

M. Andre

M. Anghinolfi

M. Anguita

M. Ardid

S. Ardid

J. Aublin

Greece

C. Bagatelas

L. Bailly-Salins

B. Baret

Netherlands

S. Pree

Y. Becherini

Morocco

M. Bendahman

F. Benfenati

E. Berbee

V. Bertin

S. Biagi

South Africa

M. Boettcher

M. Cabo

J. Boumaaza

M. Bouta

M. Bouwhuis

C. Bozza

Romania

H. Brânzaş

R. Bruijn

J. Brunner

R. Bruno

E. Buis

R. Buompane

J. Busto

B. Caiffi

D. Calvo

S. Campion

A. Capone

F. Carenini

V. Carretero

P. Castaldi

S. Celli

L. Cerisy

M. Chabab

N. Chau

A. Chen

R. Moursli

S. Cherubini

V. Chiarella

T. Chiarusi

M. Circella

R. Cocimano

J. Coelho

A. Coleiro

R. Coniglione

P. Coyle

A. Creusot

A. Cruz

G. Cuttone

R. Dallier

Y. Darras

A. Benedittis

B. Martino

R. Burgo

I. Palma

A. Dìaz

D. Diego-Tortosa

C. Distefano

A. Domi

C. Donzaud

D. Dornic

M. Dörr

E. Drakopoulou

D. Drouhin

T. Eberl

A. Eddyamoui

T. Eeden

M. Eff

D. Eijk

I. Bojaddaini

S. Hedri

A. Enzenhöfer

V. Espinosa

G. Ferrara

M. Filipović

F. Filippini

L. Fusco

J. Gabriel

T. Gal

J. Méndez

A. Soto

F. Garufi

C. Oliver

N. Geißelbrecht

L. Gialanella

E. Giorgio

A. Girardi

I. Goos

S. Gozzini

First observation of the cosmic ray shadow of the Moon and the Sun with KM3NeT/ORCA