Tootfinder

Constraining Active Galactic Nucleus Jets with Spectrum and Core Shift: The Case of M87
Kouichi Hirotani, Hsien Shang, Ruben Krasnopolsky, Satoki Matsushita, Britton Jeter, Keiichi Asada
https://arxiv.org/abs/2508.06158

Constraining Active Galactic Nucleus Jets with Spectrum and Core Shift: The Case of M87
We analytically model stationary and axisymmetric active galactic nucleus jets, assuming energy conservation along each magnetic flux tube. Using very-long-baseline interferometry (VLBI) observations and published general relativistic magnetohydrodynamic simulations, we constrain the evolution of the bulk Lorentz factor, the magnetization parameter, and the magnetic field strength along the jet. We then infer the electron density, emission coefficient, and absorption coefficient at each point, …

Standard Model Baryon Number Violation at Zero Temperature from Higgs Bubble Collisions
Nabeen Bhusal, Simone Blasi, Martina Cataldi, Aleksandr Chatrchyan, Marco Gorghetto, Geraldine Servant
https://arxiv.org/abs/2508.21825

Standard Model Baryon Number Violation at Zero Temperature from Higgs Bubble Collisions
We compute for the first time baryon number violation at zero temperature from Higgs bubble collisions and find that it can be of the same order as that from thermal sphalerons in the symmetric phase at electroweak temperatures. We study the dependence of the rate of Chern--Simons number transitions on the shape of the scalar potential and on the Lorentz factor of the bubble walls at collision via large-scale (3+1)D lattice simulations of the Higgs doublet and SU(2) gauge fields. We estimate th…

Comprehensive Statistical Analysis of Initial Lorentz Factor and Jet Opening Angle of Gamma-Ray Bursts
Jian Zhang, Bao-Cheng Qin, Lu-Lu Zhang, Fu-Wen Zhang
https://arxiv.org/abs/2508.13448

Comprehensive Statistical Analysis of Initial Lorentz Factor and Jet Opening Angle of Gamma-Ray Bursts
The initial Lorentz factor ($Γ_{0}$) and jet half-opening angle ($θ_{\rm jet}$) of gamma-ray bursts (GRBs) are critical physical parameters for understanding the dynamical evolution of relativistic jets and the true energy release of GRBs. We compile a sample of 89 GRBs that exhibit an onset bump feature in their early optical or GeV light curves, 42 of which also display a jet break feature, and derive their $Γ_{0}$ and $θ_{\rm jet}$ values. Using this sample, we re-eaxmine the correlation…

GraviGUT unification with revisited Pati-Salam model
Stephon Alexander, Bruno Alexandre, Michael Fine, Jo\~ao Magueijo, Ed\v{z}us N\=akums
https://arxiv.org/abs/2510.11674 https…

GraviGUT unification with revisited Pati-Salam model
We propose a graviGUT unification scheme based on the simple orthogonal group $\mathrm{SO}(1,9 ,\mathbb{C})$ that resolves the chiral duplication of weak isospin in Pati--Salam models. In the conventional $SU(4)\times SU(2)_+\times SU(2)_-$ framework, the unobserved second chiral $SU(2)$ is typically removed by ad hoc high-energy scale breaking. Here we instead \emph{geometrize} it: one $SU(2)$ factor is identified with a chiral half of the Lorentz group, so it belongs to gravity rather than to…

Kinetic Simulations of Particle Acceleration in Relativistic Perpendicular Electron-positron Shocks with Proton Admixture
Huan Yu, Qi Xia, Jun Fang
https://arxiv.org/abs/2510.00403

Kinetic Simulations of Particle Acceleration in Relativistic Perpendicular Electron-positron Shocks with Proton Admixture
Particle acceleration in relativistic shocks of electron-positron plasmas with proton admixture is investigated through two-dimensional (2D) particle-in-cell (PIC) simulations. The upstream plasma, with a bulk Lorentz factor of $10$ and a magnetization parameter of 0.02, includes a small fraction of protons ($\sim 5\%$ by number). A relativistic perpendicular shock is formed by reflecting the flow off a conducting wall. The shock structure, electromagnetic fields, and particle energy spectra ar…

$A_{\beta}[E_{\beta}]$ in $^{37}$K decay: new physics with opposite $\beta$ helicity
Melissa Anholm, J. A. Behr, D. G. Melconian, G. Gwinner, A. Gorelov, J. C. McNeil, B. Fenker, S. Behling
https://arxiv.org/abs/2509.11502

$A_β[E_β]$ in $^{37}$K decay: new physics with opposite $β$ helicity
By extending our analysis and simulations of our $^{37}$K $β$-decay data set to allow the $β$ asymmetry with respect to nuclear spin to vary with $β$ energy $E_β$, we have gained sensitivity to new physics that depends on a helicity factor for the $β$, $m_β/E_β$. In particular, we constrain Lorentz scalar and tensor quark-lepton interaction strengths at a sensitivity complementary to the similar Fierz interference term in neutron $β$ decay. Our result for that new physics is $b_F$…