Pulsars convert a significant fraction of their total spin-down power into very high-energy electrons, leading to the formation of TeV halos. While these halos are well characterized at TeV energies, it remains unclear whether pulsars also accelerate electrons efficiently at lower energies and how these particles propagate through their surrounding environments. We aim to test whether synchrotron emission from $$\sim 50$$ – $$300 \, \textrm{GeV}$$ electrons around the Geminga pulsar can be detected in the frequency range observed by the Planck satellite. This would help constrain low-energy particle acceleration and diffusion in the vicinity of pulsars. We model the expected synchrotron emission from Geminga’s TeV halo based on various diffusion and injection spectrum scenarios and compare these predictions to publicly available multi-frequency Planck data. We find no conclusive evidence of spatially extended synchrotron emission associated with Geminga in any of Planck’s frequency bands. Our calculations show that even under favorable diffusion and injection conditions, the predicted synchrotron flux lies well below Planck’s measured background levels.

United States

D. Hooper

E. Pinetti

A. Sokolenko

Searching for synchrotron emission from the geminga TeV halo using the planck satellite

<p>We investigate photon, pion, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>ρ</mi></mrow></math>-meson production from proton synchrotron radiation in the presence of strong magnetic fields. The proton decay widths and the luminosities of the emitted particles are calculated within a relativistic quantum framework that incorporates Landau quantization. A scaling rule is derived for the transition probability between different Landau levels. This allows an evaluation of transitions for extremely high Landau numbers exceeding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mn>15</mn></msup></math>. Furthermore, we calculate the momentum distribution of the emitted particles by properly including the proton recoil effect associated with particle emission. The results differ significantly from conventional semiclassical approaches.</p>

Japan

Tomoyuki Maruyama

A. Baha Balantekin

South Korea

Myung-Ki Cheoun

Akira Dohi

Ryo Higuchi

China

Toshitaka Kajino

Grant J. Mathews

High energy particle production from proton synchrotron radiation in strong magnetic fields in relativistic quantum field theory

<p>Using the Kadanoff-Baym formalism, we perform a detailed study of neutrino-antineutrino synchrotron emission from strongly magnetized, dense quark matter under conditions relevant to compact stars. Starting from an exact expression for the emission rate that fully accounts for Landau-level quantization of quarks, we derive an approximate formula applicable in the regime where quark chemical potentials are much larger than all other relevant energy scales. We demonstrate that the emission rate is largely controlled by a single dimensionless ratio between two low-energy scales: the Landau-level spacing at the Fermi surface, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>e</mi><mi>f</mi></msub><mi>B</mi><mo stretchy="false">|</mo><mo>/</mo><msub><mi>μ</mi><mi>f</mi></msub></math>, and the temperature of the quark matter, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>. When the ratio <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>e</mi><mi>f</mi></msub><mi>B</mi><mo stretchy="false">|</mo><mo>/</mo><mo stretchy="false">(</mo><msub><mi>μ</mi><mi>f</mi></msub><mi>T</mi><mo stretchy="false">)</mo></math> approaches zero, many closely spaced Landau levels contribute to the emission, but the total rate vanishes as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mn>0</mn></math>. In the opposite limit, where the ratio is large, the rate is dominated by transitions between adjacent levels and is exponentially suppressed due to Landau-level quantization, which limits the thermal activation of quarks near the Fermi surface. Our results show that, even in the presence of the strongest magnetic fields expected in compact stars, the synchrotron emission remains suppressed by more than 3 orders of magnitude compared to the direct Urca process. This implies that such emission is unlikely to play any substantial role in the cooling of magnetized quark stars, at least those made of unpaired quark matter phases.</p>

Ritesh Ghosh

Igor A. Shovkovy

Neutrino-antineutrino synchrotron emission from magnetized dense quark matter

A Muon (Synchrotron) Ion Collider (MuSIC) can be the successor to the Electron-Ion Collider at Brookhaven National Laboratory, as well as the ideal demonstrator facility for a future multi-TeV Muon Collider. Besides its rich nuclear physics and Standard Model particle physics programs, in this work we show that the MuSIC with a TeV-scale muon beam offers also a unique opportunity to probe New Physics. In particular, the relevant searches have the potential to surpass current experimental limits and explore new regimes of the parameter space for a variety of Beyond the Standard Model scenarios including: lepton-flavor violating leptoquarks, muonphilic vector boson interactions, axion-like particles coupling to photons, and heavy sterile neutrinos. Depending on the particular case, the sensitivity of the searches in the MuSIC may span a wide range of energy scales, namely from sub-GeV particles to the few TeV New Physics mediators. Our analysis demonstrates that the MuSIC can strike a powerful chord in the search for New Physics, thanks to unique combination of features that amplify its capabilities.

Hooman Davoudiasl

Israel

Hongkai Liu

Roman Marcarelli

Yotam Soreq

Sokratis Trifinopoulos

New physics at the Muon (Synchrotron) Ion Collider: MuSIC for several scales

We studied synchrotron radiation of a massive charged under visible and hidden sector groups, moving in equatorial plane around spherically symmetric weakly magnetized black hole. As a model of dark matter we choose the one, in which Maxwell field is coupled to the additional (1)-gauge field envisaging the dark sector, the so-called dark photon model. Magnetization of a black hole also stems from Maxwell-dark photon electrodynamics. One found the radiation power and energy loss of the particle and looked for the imprints of dark matter on those phenomena.

Poland

Marek Rogatko

Paritosh Verma

Can synchrotron radiation reveal the presence of

In this paper, we investigate the polarization images of a synchrotron-emitting fluid ring surrounding a static hairy black hole within the framework of Horndeski’s theory. Our findings indicate that the characteristics of these polarization images are predominantly influenced by the hairy parameter, alongside the magnetic field near the black hole, the fluid’s velocity, and the observer’s inclination angle. Specifically, the hairy parameter primarily affects the polarized intensity and the apparent radius of the ring in the images. Conversely, the impacts of the magnetic field, fluid velocity, and inclination angle on the polarization images are found to be independent of the hairy parameter and closely resemble those observed in the context of Schwarzschild black holes. Additionally, the polarization direction is significantly influenced by the magnetic field orientation, while the inclination angle crucially determines the apparent flatness of the images. Variations in the fluid velocity direction also markedly affect the trend in polarized intensity. Furthermore, we explore how these parameters influence the Stokes  $$Q-U$$  <math> <mrow> <mi>Q</mi> <mo>-</mo> <mi>U</mi> </mrow> </math>   loops, revealing distinct behaviors in response to changes in the aforementioned variables. This comprehensive analysis enhances our understanding of the intricate dynamics and observational signatures of black holes within alternative gravitational theories.

Han-Yu Shi

Tao Zhu

Polarized image of a synchrotron emitting ring around a static hairy black hole in Horndeski theory

If the cosmological dark matter (DM) couples to Standard Model (SM) fields, it can decay promptly to SM states in a highly energetic hard process, which subsequently showers and hadronizes to give stable particles including <math><msup><mi>e</mi><mo>±</mo></msup></math>, <math><mi>γ</mi></math>, <math><msup><mi>p</mi><mo>±</mo></msup></math>, and <math><mi>ν</mi><mover><mi>ν</mi><mo>¯</mo></mover></math> at lower energy. If the DM particle is very heavy, the high-energy <math><msup><mi>e</mi><mo>±</mo></msup></math>, due to the Klein-Nishina cross section suppression, preferentially lose energy via synchrotron emission which, in turn, can be of unusually high energies. Here, we present previously unexplored bounds on heavy decaying DM up to the Planck scale, by studying the synchrotron emission from the <math><msup><mi>e</mi><mo>±</mo></msup></math> produced in the ambient Galactic magnetic field. In particular, we explore the sensitivity of the resulting constraints on the DM decay width to (i) different SM decay channels, to (ii) the Galactic magnetic field configurations, and to (iii) various different DM density profiles proposed in the literature. We find that constraints from the synchrotron component complement and improve on constraints from very high-energy cosmic-ray and gamma-ray observatories targeting the prompt emission when the DM is sufficiently massive, most significantly for masses in excess of <math><msup><mn>10</mn><mn>12</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>.

Pankaj Munbodh

Stefano Profumo

Astrophysical constraints from synchrotron emission on very massive decaying dark matter

We investigate the potential of the Square Kilometre Array (SKA) in detecting synchrotron radiation emitted from the decay of sub-GeV dark matter (dark matter with masses below the GeV scale) in the presence of strong magnetic fields. As a concrete setup, we consider scenarios where the magnetosphere of a magnetic white dwarf overlaps with dense dark matter environments, such as those surrounding a primordial black hole. Our study reveals that the encounters of compact objects such as white dwarfs and black holes offer a promising avenue for upcoming radio telescopes to probe the properties of light dark matter, which has been less explored compared with more conventional heavier (masses above the GeV scale) dark matter.

Kenji Kadota

Shota Kisaka

SKA sensitivity to sub-GeV dark matter decay: Synchrotron radio emissions in white dwarf magnetospheres

The paper has explored analogue of gravitational synchrotron massive particle and Penrose process in MOdified Gravity (MOG) known as Scalar-Tensor-Vector-Gravity (STVG). Investigation of the gravitational field around Kerr-MOG black hole showed that it has strong gravitational field with large horizon and can rotate faster than Kerr black hole due to the effect of STVG. We have studied influence of STVG in circular motion of massive particle around Kerr-MOG black hole and discussed the Innermost Stable Circular Orbit (ISCO) of massive test particle. It is shown that STVG plays a crucial role in energy extraction from a rotating black hole, with an energy efficiency of more than 100% according to the Penrose process. Furthermore, we have explored the gravitational synchrotron radiation analogue produced by a massive particle orbiting around a Kerr-MOG black hole. It has been shown that the intensity of gravitational radiation from binary systems of stellar black holes (SBH) and supermassive black holes (SMBH).

Uzbekistan

Bobur Turimov

Husan Alibekov

Pulat Tadjimuratov

Ahmadjon Abdujabbarov

Gravitational synchrotron radiation and Penrose process in STVG theory

The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration, using $\sqrt{s} = 13$ TeV proton–proton collision data with an integrated luminosity of 140 fb $^{-1}$ collected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is established to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.

France

G. Aad

B. Abbott

Germany

K. Abeling

N.J. Abicht

S.H. Abidi

Morocco

A. Aboulhorma

H. Abramowicz

H. Abreu

Y. Abulaiti

Italy

United Kingdom

B.S. Acharya

C. Adam Bourdarios

L. Adamczyk

S.V. Addepalli

M.J. Addison

J. Adelman

A. Adiguzel

T. Adye

A.A. Affolder

Switzerland

Y. Afik

Spain

M.N. Agaras

J. Agarwala

A. Aggarwal

Romania

C. Agheorghiesei

A. Ahmad

Azerbaijan

F. Ahmadov

Canada

W.S. Ahmed

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

I. Aizenberg

M. Akbiyik

Sweden

T.P.A. Åkesson

A.V. Akimov

D. Akiyama

N.N. Akolkar

K. Al Khoury

G.L. Alberghi

J. Albert

P. Albicocco

G.L. Albouy

S. Alderweireldt

M. Aleksa

I.N. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

H.M.J. Ali

S. Ali

S.W. Alibocus

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B.M.M. Allbrooke

J.F. Allen

Chile

C.A. Allendes Flores

P.P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

M. Alvarez Estevez

A. Alvarez Fernandez

M. Alves Cardoso

M.G. Alviggi

M. Aly

Brazil

Y. Amaral Coutinho

A. Ambler

C. Amelung

M. Amerl

C.G. Ames

D. Amidei

Portugal

S.P. Amor Dos Santos

K.R. Amos

Norway

V. Ananiev

C. Anastopoulos

T. Andeen

J.K. Anders

S.Y. Andrean

A. Andreazza

S. Angelidakis

A. Angerami

A.V. Anisenkov

A. Annovi

C. Antel

M.T. Anthony

E. Antipov

M. Antonelli

F. Anulli

M. Aoki

T. Aoki

J.A. Aparisi Pozo

M.A. Aparo

L. Aperio Bella

C. Appelt

Performance and calibration of quark/gluon-jet taggers using 140 fb$^{−1}$ of $\textit{pp}$ collisions at ${{\sqrt{\boldsymbol s}\bf = 13}}$ TeV with the ATLAS detector * We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taipei; TENMAK, Türkiye; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, CANARIE, CRC and DRAC, Canada; PRIMUS 21/SCI/017 and UNCE SCI/013, Czech Republic; COST, ERC, ERDF, Horizon 2020, ICSC-Next Generation EU and Marie Skłodowska-Curie Actions, European Union; Investissements d'Avenir Labex, Investissements d'Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and MINERVA, Israel; Norwegian Financial Mechanism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelse, Sweden; The Royal Society and Leverhulme Trust, United Kingdom.