SEARCH · Search NASA

Results for “Muons”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Replication Data for: Measurement of the mean number of muons with energies above 500 GeV in air showers detected with the IceCube Neutrino Observatory

Measurement of the mean number of muons with energies above 500 GeV in air showers detected with the IceCube Neutrino Observatory This data release accompanies results submitted to Physical Review D describing the measurement of the average multiplicity of TeV muons with IceCube. It contains the data necessary to reproduce the main plots from the paper (Figs. 7 and 9), i.e. the numerical results for the average number of muons with energies above 500 GeV as a function of primary cosmic ray energy. For any questions about this data release, please write to analysis@icecube.wisc.edu. Files included in this release: <ul> <li>A README file <li>Files including data to reproduce the results plots from the paper (see below for details) <li>An example python script showing how to read and plot the data </ul> What is in the files icecube_Nmu500_X_Y.txt: Y indicates wether the file contains values obtained from experimental data (Y="data") or air-shower simulations (Y="MC"). X indicates the hadronic interaction model for which the plot is made. If Y="data", this means that the experimental data was interpreted using this model. If Y="MC", it means that the simulations were performed with this model. The three models included are Sibyll 2.1, QGSJet-II.04, and EPOS-LHC (see paper for references). The file with X="modelaverage" gives the average over the three individual results with the deviations from the average included in the systematic uncertainties. Please see the README file for details on how the data is structured in the files.

Astroparticle Physics↗

DOE OSTI2025

Measurements at forward rapidity of elliptic flow of charged hadrons and open-heavy-flavor muons in Au + Au collisions at $\sqrt{𝑠_{𝑁⁢𝑁}}$ = 200 GeV

Here, we present the first forward-rapidity measurements of elliptic anisotropy of open-heavy-flavor muons at the Relativistic Heavy Ion Collider. The measurements are based on data samples of Au + Au collisions at $\sqrt{𝑠_{𝑁⁢𝑁}}$ = 200 GeV collected by the PHENIX experiment in 2014 and 2016 with integrated luminosity of 14.5 nb −1 . The measurements are performed in the pseudorapidity range 1.2 < |𝜂| < 2 and cover transverse momenta 1< 𝑝 𝑇 < 4 GeV/𝑐. The elliptic flow of charged hadrons as a function of transverse momentum is also measured in the same kinematic range. We observe significant elliptic flow for both charged hadrons and heavy-flavor muons. The results show clear mass ordering of elliptic flow of light- and heavy-flavor particles. The magnitude of the measured 𝑣 2 is comparable to that in the midrapidity region. This indicates that there is no strong longitudinal dependence in the quark-gluon-plasma evolution between midrapidity and the rapidity range of this measurement at $\sqrt{𝑠_{𝑁⁢𝑁}}$ = 200 GeV.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2025

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

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.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2026

Search for low-mass hidden-valley dark showers with non-prompt muon pairs in proton-proton collisions at $\sqrt{s}=13$ TeV

A search for signatures of a dark analog to quantum chromodynamics is performed. The analysis targets long-lived dark mesons that decay into standard-model particles, with a high branching fraction of the dark mesons decaying into muons. The dark mesons are formed by the hadronisation of dark partons, which are produced by a decay of the Higgs boson. The search is performed using a data set corresponding to an integrated luminosity of 41.6 fb −1 , which was collected in proton-proton collisions at $\sqrt{s}=13$ TeV by the CMS experiment at the CERN LHC in 2018 using non-prompt muon triggers. The search is based on resonant muon pair signatures. Machine-learning techniques are employed in the analysis, utilising boosted decision trees to discriminate between signal and background. No significant excess is observed above the standard model expectation. Upper limits on the branching fraction of the Higgs boson decaying to dark partons are determined to be as low as 10−4 at 95% confidence level, surpassing and extending the existing limits on models with dark $\tilde{ω}$ mesons for mean proper decay lengths of less than 500 mm and for $\tilde{ω}$ masses down to 0.3 GeV. First limits are set for extended dark-shower models with two dark flavours that contain dark photons, probing their masses down to 0.33 GeV.

Beyond Standard Model↗

DOE OSTI2024

Probing the CP structure of the top quark Yukawa at the future muon collider

We study the top-Higgs coupling with a CP violating phase ξ at a future multi-TeV muon collider. We focus on processes that are directly sensitive to the top quark Yukawa coupling: $t$$\overline{t}$$h$, $tbhμν$, and $t$$\overline{t}$$h$$v$$\overline{v}$ with $h$ → $b$$\overline{b}$ and semileptonic top decays. At different energies, different processes dominate the cross section, providing complementary information. At and above an energy of $\mathcal{O}$(10) TeV, vector boson fusion processes dominate. As we show, in the Standard Model there is destructive interference in the vector boson fusion processes $t$$\overline{t}$$h$$v$$\overline{v}$ and $tbhμν$ between the top quark Yukawa and Higgs-gauge boson couplings. A CP-violating phase changes this interference, and the cross section measurement is very sensitive to the size of the CP-violating angle. Although we find that the cross sections are measured to $\mathcal{O}$(50%) statistical uncertainty at 1σ, a 10 and 30 TeV muon collider can bound the CP-violating angle |ξ| ≲ 9.0° and |ξ| ≲ 5.4°, respectively. However, cross section measurements are insensitive to the sign of the CP-violating angle. To determine that the coupling is truly CP violating, observables sensitive to CP-violation must be measured. We find in the $t$$\overline{t}$$h$ process the azimuthal angle between the $t$ + $\overline{t}$ plane and the initial state muon+Higgs plane shows good discrimination for ξ = ±0.1π.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

The new physics case for beam-dump experiments with accelerated muon beams

As the field examines a future muon collider as a possible successor to the LHC, we must consider how to fully utilize not only the high-energy particle collisions, but also any lower-energy staging facilities necessary in the R&D process. An economical and efficient possibility is to use the accelerated muon beam from either the full experiment or from cooling and acceleration tests in beam-dump experiments. Beam-dump experiments are complementary to the main collider as they achieve sensitivity to very small couplings with minimal instrumentation. We demonstrate the utility of muon beam-dump experiments for new physics searches at energies from 10 GeV to 5 TeV. We find that, even at low energies like those accessible at staging or demonstrator facilities, it is possible to probe new regions of parameter space for a variety of generic BSM models, including muonphilic, leptophilic, L μ − L τ , and dark photon scenarios. Such experiments could therefore provide opportunities for discovery of new physics well before the completion of the full multi-TeV collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2025

First measurement of differential cross sections for muon neutrino charged current interactions on argon with a two-proton final state using the MicroBooNE detector

We present the first measurement of differential cross sections for charged-current muon neutrino interactions on argon with one muon, two protons, and no pions in the final state. These final states are dominated by two-nucleon knockout interactions, which are complicated to model and for which there is currently limited information about the characteristics of these interactions in existing neutrino-nucleus scattering data. Detailed investigations of two-nucleon knockout are vital to support upcoming experiments exploring the nature of the neutrino. Among the different kinematic quantities measured, the opening angle between the two protons, the angle between the total proton momentum and the muon, and the total transverse momentum of the final state system are most sensitive to the underlying physics processes as embodied in various theoretical models.

2-particle 2-hole states↗

DOE OSTI2025

Latest results of the Muon g-2 experiment at Fermilab

The muon magnetic anomaly, aμ = g - 2/ 2, is a low-energy observable which can be both measured and computed to high precision, making it a sensitive test of the Standard Model and a probe for new physics. The Muon g − 2 experiment at Fermilab aims to measure aμ with a final accuracy of 140 parts per billion (ppb). The experiment is based on the measurement of the muon spin anomalous precession frequency, ωa, in a magnetic field. The first result of the experiment, based on the 2018 data-taking campaign, was published in 2021 and it confirmed the previous result obtained at Brookhaven National Laboratory with a similar sensitivity of 460 ppb. In this proceeding, the result based on the 2019 and 2020 datasets is presented and the improvement in the accuracy with respect to the 2018 dataset are discussed.

Sorbara, Matteo [INFN, Rome2; Rome U., Tor Vergata↗

DOE OSTI2025

Muon tagging with flash ADC waveform baselines

Here, this manuscript describes an innovative method to tag muons using the baseline information of the Flash ADC (FADC) waveform of PMTs in the JSNS 2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment. The experiment is designed to search for evidence of sterile neutrinos, and a reliable method for muon tagging is an essential component for background rejection because the detector is located above ground, on the 3rd floor of the J-PARC Material and Life Science Experimental Facility (MLF). Cosmogenic muons that stop within the detector volume and produce a Michel electron are a particularly important background that must be rejected for our sterile neutrino search. Utilizing this innovative method, more than 99.8 % of Michel electrons can be rejected even without using information from the detector’s veto region PMTs. This technique can be employed by any experiments which uses a similar detector configuration.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2026

Search for 𝑏-hadron decays to long-lived particles in the CMS endcap muon detectors

A search for long-lived particles originating from the decay of 𝑏 hadrons produced in proton-proton collisions with a center-of-mass energy of 13 TeV at the LHC is presented. The analysis is performed on a dataset recorded in 2018, corresponding to an integrated luminosity of 41.6 fb −1 . Interactions of the long-lived particles in the CMS endcap muon system would create hadronic or electromagnetic showers, producing clusters of detector hits. Selected events contain at least one such high-multiplicity cluster in the muon endcaps and require the presence of a displaced muon. The most stringent upper limits to date on the branching fraction ℬ⁡(𝐵 →𝐾⁢Φ), where the long-lived particle Φ decays to a pair of hadrons, are obtained for Φ masses of 0.3–3.0 GeV and Φ mean proper decay lengths in the range of 1–500 cm.

Hayrapetyan, A. [Yerevan Physics Institute]↗

DOE OSTI2025

Measurement of muon neutrino induced charged current interactions without charged pions in the final state using a new T2K off-axis near detector WAGASCI-BabyMIND

We report a flux-integrated cross section measurement of muon neutrino interactions on water and hydrocarbon via charged current reactions without charged pions in the final state with the WAGASCI-BabyMIND detector, which was installed in the T2K near detector hall in 2018. The detector is located 1.5° off-axis and is exposed to a more energetic neutrino flux than ND280, another T2K near detector, which is located at a different off-axis position. The total flux-integrated cross section is measured to be 1.26 ± 0.18⁢(stat+syst) × 10 −39 cm 2 /nucleon on CH and 1.44 ± 0.21⁢(stat+syst) × 10 −39 cm 2 /nucleon on H 2 ⁡O. These results are compared to model predictions provided by the neut v5.3.2 and genie v2.8.0 Monte Carlo generators and the measurements are compatible with these models. Differential cross sections in muon momentum and cosine of the muon scattering angle are also reported. This is the first such measurement reported with the WAGASCI-BabyMIND detector and utilizes the 2020 and 2021 datasets.

lepton-hadron interactions↗

DOE OSTI2024

Diphoton signals of muon-philic scalars at DarkQuest

We analyze the capability of the DarkQuest proton beam-dump experiment at Fermilab to discover new light resonances decaying into photons. As an example model, we focus on muon-philic scalar particles that decay to photons. This is one of the few minimal models that can address the ( g − 2 ) μ anomaly at low mass. These scalars can be copiously produced by meson decays and muon bremsstrahlung. We point out that thanks to DarkQuest’s compact geometry, muons can propagate through the dump and efficiently produce dark scalars near the end of the dump. This mechanism enables DarkQuest to be sensitive to both long-lived and prompt scalars. At the same time, diphoton signatures are generically not background free, and we discuss in detail the different sources of background and strategies to mitigate them. We find that the backgrounds can be sufficiently reduced for DarkQuest to test currently viable ( g − 2 ) μ parameter space. Published by the American Physical Society 2024

Blinov, Nikita (ORCID:000000022845961X)↗

DOE OSTI2025

Neutrino-portal dark matter detection prospects at a future muon collider

With no concrete evidence for nongravitational interactions of dark matter to date, it is natural to wonder whether dark matter couples predominantly to the Standard Model (SM)’s neutrinos. Neutrino interactions (and the possible existence of additional neutrinophilic mediators) are substantially less understood than those of other SM particles, yet this picture will change dramatically in the coming decades with new neutrino sources. One potential new source arises with the construction of a high-energy muon collider (MuCol); due to muons’ instability, a MuCol is a source of high-energy collimated neutrinos. Importantly, since the physics of muon decays (into neutrinos) is very well-understood, this leads to a neutrino flux with systematic uncertainties far smaller than fluxes from conventional high-energy (proton-sourced) neutrino beams. In this work, we study the capabilities of a potential neutrino detector, “ MuCol ν ”, placed ∼ 100 m downstream of the MuCol interaction point. The MuCol ν detector would be especially capable of searching for a neutrinophilic mediator ϕ through the mononeutrino scattering process ν μ N → μ + ϕ X , exceeding searches from other terrestrial approaches for m ϕ in the ∼ few MeV- ten GeV range. Even with a 10 kg-yr exposure, MuCol ν is capable of searching for well-motivated classes of thermal freeze-out and freeze-in neutrino-portal dark matter. Published by the American Physical Society 2025

Adhikary, Jyotismita (ORCID:0000000253894170)↗

DOE OSTI2025

Aspects of Higgs Physics at a $\sqrt{s}=3$ TeV Muon Collider with detailed detector simulation

The Muon Collider is one of the most promising future collider facilities with the potential to reach multi-TeV center-of-mass energy and high luminosity. Due to the significant Higgs boson production cross section in muon-antimuon collisions at such high energies, the collider offers an excellent opportunity for in-depth exploration of Higgs boson properties. It holds the capability to significantly advance our understanding of the Higgs sector to a very high level of precision. However, the presence of beam-induced background resulting from the decay of the beam muons poses unique challenges for detector development and event reconstruction. In this paper, the prospects for measuring various Higgs boson properties at a center-of-mass energy of 3 TeV are presented, using a detailed detector simulation in a realistic environment. The study demonstrates the feasibility of achieving high precision results with the current state-of-the-art detector design. In addition, the paper discusses the detector requirements necessary to achieve this level of accuracy.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Proposed muon collider R&D at SNS

Generation of a muon beam at a Muon Collider requires relatively short, high-charge proton bunches. They are produced in a high-average-power proton driver by first accumulating a proton beam from a super-conducting linac, then bunching the beam and finally compressing and combining the bunches into a single high-intensity proton pulse. All of these beam formation stages involve handling of unprecedentedly high beam charges. Validation of these intricate beam manipulations requires better understanding of extreme space-charge effects and experimental demonstration. A facility perhaps most closely resembling the proton driver configuration and beam parameters is the Spallation Neutron Source (SNS) accelerator complex at Oak Ridge National Laboratory (ORNL). Considering the energy scaling of the space-charge parameters, many of the beam formation steps planned for the proton driver can be experimentally checked at the SNS at the relevant space-charge interaction levels. This paper discusses potential proton driver and other muon-collider-related R\&D at the SNS.

43 PARTICLE ACCELERATORS↗

DOE OSTI2025

On Final Results From the Muon $g\mathrm{-}2$ Experiment at Fermilab

The Muon g-2 Experiment at Fermilab has measured the muon anomalous magnetic moment, a_mu, with unprecedented precision, leveraging a dataset from Runs 1 6 that is 21 times larger than its Brookhaven predecessor. This talk will present the experiment s final result, which serves as a benchmark for testing the Standard Model with high precision. The measurement was performed in a storage ring with a highly uniform magnetic field, where precise beam dynamics understanding is vital to determine the muon anomalous precession frequency. Key to this effort were advanced simulation tools including COSY INFINITY, precise fringe field modeling, and calculations of beam dynamics characteristics like tunes and chromaticity. We will conclude by exploring how the experiment's findings reshape our understanding of particle physics.

Valetov, Eremey [Michigan State U.]↗

DOE OSTI2025

Simulating Muon Capture with MARLEY

Core-collapse supernovae are intense sources of tens-of-MeV neutrinos. Each explosion releases about 1058 neutrinos in a burst lasting tens of seconds. As neutrinos are weakly interacting, they escape more easily compared to photons, allowing them to be observed before the light signal. Understanding low-energy neutrino interactions with argon will be critical for future supernova measurements with the Deep Underground Neutrino Experiment (DUNE). Interpreting future DUNE supernova neutrino data will require a high-quality model of O(10 MeV) neutrino interactions, but the dominant charged-current cross section has never been measured at these low energies for an argon target. We exploit the theoretical similarities between muon capture, which has been measured, and antineutrino scattering to test MARLEY (Model of Argon Reaction Low Energy Yields), the simulation code used by DUNE to model supernova neutrino reactions. I implemented C++ code to add a muon capture mode to MARLEY and compared the predictions of the new simulation to measured isotope branching ratios of the residual nuclei. The preliminary branching ratios predicted by MARLEY running in muon capture mode demonstrate promising baseline performance when compared to experimental data and are expected to improve with further model adjustments.

Wong, Baker Louie↗

DOE OSTI2025

Laser calibration system and lost muons correction in the g-2 experiment

The Muon g-2 experiment at Fermilab has the main goal to measure the muon anomalous magnetic moment $a_{µ}$ = ($g$ − 2)/2 to a precision of 0.14 parts per million (ppm), which means 4 times improvement in precision with respect to the final result from BNL: $a_{µ}$ (expt. BNL) = 11659208.0(6.3) × 10$^{−10}$ (0.54 ppm) In this report I summarize the work done at the $g$-2 experiment during my summer internship at Fermilab. In the first two weeks my first task has been to replace the NIM logic used in the Laser Calibration System with a new FPGA. Then, I was involved in the Lost Muons analysis studying both real data and MonteCarlo simulations.

43 PARTICLE ACCELERATORS↗