arXiv subjects

Mira Littmann

Publications and source records attributed to Mira Littmann.

6 recordsLinked to original sources

arXiv2026

On-Detector Machine Learning for Beam-Induced Background Rejection at a 10 TeV Muon Collider

A 10 TeV Muon Collider is a compelling candidate for a future energy-frontier facility, offering unprecedented opportunities to explore the fundamental laws of particle physics. Muon decays in the collider ring produce intense beam-induced background (BIB) that can overwhelm detector occupancy and exceed readout bandwidth constraints. We investigate the potential of on-detector Machine Learning for BIB rejection in the vertex detector, exploiting pixel cluster shapes to distinguish background from collision products. We study three classes of lightweight neural-network architectures, and evaluate their implementation feasibility using high-level synthesis. Selected architectures achieve 88 to 90% data reduction at 99% signal efficiency, while requiring hardware resources compatible with potential ASIC implementation. These results demonstrate the potential of performing substantial BIB rejection directly in the pixel readout, providing a strategy for meeting the tracker readout requirements at a future Muon Collider.

hep-ex↗

arXiv2025

Enabling searches for long-lived particles at a future 10 TeV Muon Collider

Muon Colliders offer fantastic opportunities to explore new phenomena at the energy frontier. However, beam-induced-backgrounds from muon decays pose significant challenges for detector design, readout, and reconstruction. Previous detector studies have employed stringent hit-timing requirements to reduce occupancy to manageable levels with negligible efficiency loss for prompt Standard Model particles. In the spirit of maximizing discovery potential, we investigate the capability of detecting meta-stable charged long-lived particles at a 10 TeV Muon Collider. As a benchmark, we consider a Gauge Mediated Supersymmetry Breaking (GMSB) model in which the stau is long-lived and can be identified as a high momentum, slowly moving track. We find that nominal hit-timing selections are too restrictive, and investigate the impact of looser requirements. We demonstrate that it is possible to recover sensitivity to particles with masses close to $\sqrt{s}/2$ by expanding time acceptance, and provide recommendations to further improve tracker design and track reconstruction.

hep-ex↗

arXiv2025

Characterization of a 28 nm $\textit{smartpixels}$ ASIC With On-Chip ML for Particle Tracking Detectors

We present a 28 nm CMOS pixel readout integrated circuit implementing in-pixel analog signal processing and on-chip machine learning data filtering for particle tracking detectors. Our ASIC comprises two $32 \times 8$ pixel matrices with a pixel pitch of $25 \times 25~\mu\mathrm{m}^2$, in which each pixel integrates a charge-sensitive amplifier with synchronous auto-zero offset cancellation and a 2-bit flash ADC with programmable thresholds. Two analog front-end architectures, single-ended and differential, are implemented and characterized. Digitized pixel data are combined into row-wise projections and processed by an on-chip, fully combinational neural network classifier for data reduction. Measurements at room temperature using charge injection demonstrate an equivalent noise charge of $54.6~\mathrm{e}^{-}$ and a threshold dispersion of $\sim$78.2~\unit{\electron} at nominal bias, linear response up to several~\unit{\kilo\electron}, and stable operation at a 10~MHz clock frequency. The neural network output is compared with offline RTL predictions and agrees for $99.06\%$ of $1.5 \times 10^{5}$ test inputs.

physics.ins-det↗

arXiv2025

Entanglement Maximization and Mirror Symmetry in Two-Higgs-Doublet Models

We consider 2-to-2 scatterings of Higgs bosons in a CP-conserving two-Higgs-doublet model (2HDM) and study the implication of maximizing the entanglement in the flavor space, where the two doublets $\Phi_a$, $a=1,2$, can be viewed as a qubit: $\Phi_1=|0\rangle$ and $\Phi_2=|1\rangle$. More specifically, we compute the scattering amplitudes for $\Phi_a \Phi_b \to \Phi_c \Phi_d$ and require the outgoing flavor entanglement to be maximal for a full product basis such as the computational basis, which consists of $\{|00\rangle,|01\rangle,|10\rangle,|11\rangle\}$. In the unbroken phase and turning off the gauge interactions, entanglement maximization results in the appearance of an $U(2)\times U(2)$ global symmetry among the quartic couplings, which in general is broken softly by the mass terms. Interestingly, once the Higgs bosons acquire vacuum expectation values, maximal entanglement enforces an exact $U(2) \times U(2)$ symmetry, which is spontaneously broken to $U(1)\times U(1)$. As a byproduct, this gives rise to Higgs alignment as well as to the existence of 6 massless Nambu-Goldstone bosons. The $U(2)\times U(2)$ symmetry can be gauged to lift the massless Goldstones, while maintaining maximal entanglement demands the presence of a discrete $\mathrm{Z}_2$ symmetry interchanging the two gauge sectors. The model is custodially invariant in the scalar sector, and the inclusion of fermions requires a mirror dark sector, related to the standard one by the $\mathrm{Z}_2$ symmetry.

hep-ph↗

arXiv2025

First Axion-Like Particle Results from a Broadband Search for Wave-Like Dark Matter in the 44 to 52 $\mu$eV Range with a Coaxial Dish Antenna

We present the results from the first axion-like particle search conducted using a dish antenna. The experiment was conducted at room temperature and sensitive to axion-like particles in the $44-52\,\mu\mathrm{eV}$ range ($10.7 - 12.5\,\mathrm{GHz}$). The novel dish antenna geometry was proposed by the BREAD collaboration and previously used to conduct a dark photon search in the same mass range. To allow for axion-like particle sensitivity, the BREAD dish antenna was placed in a $3.9\,\mathrm{T}$ solenoid magnet at Argonne National Laboratory. In the presence of a magnetic field, axion-like dark matter converts to photons at the conductive surface of the reflector. The signal is focused onto a custom coaxial horn antenna and read out with a low-noise radio-frequency receiver. No evidence of axion-like dark matter was observed in this mass range and we place the most stringent laboratory constraints on the axion-photon coupling strength, $g_{a\gamma\gamma}$, in this mass range at 90\% confidence.

hep-ex↗

arXiv2024

First Results from a Broadband Search for Dark Photon Dark Matter in the $44$ to $52\,μ$eV range with a coaxial dish antenna

We present first results from a dark photon dark matter search in the mass range from 44 to 52 $μ{\rm eV}$ ($10.7 - 12.5\,{\rm GHz}$) using a room-temperature dish antenna setup called GigaBREAD. Dark photon dark matter converts to ordinary photons on a cylindrical metallic emission surface with area $0.5\,{\rm m}^2$ and is focused by a novel parabolic reflector onto a horn antenna. Signals are read out with a low-noise receiver system. A first data taking run with 24 days of data does not show evidence for dark photon dark matter in this mass range, excluding dark photon - photon mixing parameters $χ\gtrsim 10^{-12}$ in this range at 90% confidence level. This surpasses existing constraints by about two orders of magnitude and is the most stringent bound on dark photons in this range below 49 $μ$eV.

hep-ex↗