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At least 91 records · Page 5

Atmospheric muons and neutrinos, and the neutrino-induced muon flux underground

The diffusion equation for neutrino-induced cosmic ray muons underground was solved. The neutrino-induced muon flux and charge ratio underground have been calculated. The calculated horizontal neutrino-induced muon flux in the energy range 0.1 - 10000 GeV is in agreement with the measured horizontal flux. The calculated vertical flux above 2 GeV is in agreement with the measured vertical flux. The average charge ratio of neutrino-induced muons underground was found to be mu+/mu- = 0.40.

Liland, A.↗

Muon Intensity Increase by Wedge Absorbers for Low-E Muon Experiments

Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the matched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.

43 PARTICLE ACCELERATORS↗

A Collaboration Website for Muon Catalyzed Fusion and Muon Beam Production

This research initiative establishes a dynamic online platform geared towards supporting the burgeoning Muon Catalyzed Fusion collaboration, focusing on the concurrent development of particle accelerators and transport beamlines for muon beams. The central feature of this endeavor is the creation of a multifaceted website comprising both public facing and private sections to cater to diverse user needs. The public segment is meticulously designed to serve as an educational hub, featuring information pages targeted at the general public alongside private pages exclusively accessible to collaboration members. These pages will host an array of multimedia elements, ranging from images and text animations to video lectures, covering an extensive spectrum of topics integral to the science of Muon Catalyzed Fusion. Encompassing areas such as Acceleration, Applications, Instrumentation, Beamline Design, and beam dynamics design codes, the educational content aims to make complex scientific concepts more accessible to a broader audience. Ensuring seamless accessibility across various devices and operating systems, the website incorporates integration with collaborative tools such as Google Docs for document collaboration, GitHub for code repository management, and WordPress for blogging with interactive commenting features. The bifurcation between public and private sections is a strategic approach to maintaining transparency while safeguarding proprietary research and works in progress. The public pages are strategically crafted to disseminate information, showcasing the latest endeavors and achievements within the NK Labs collaboration, including lectures, published papers, and regular blog posts open to public comments. On the other hand, the private section provides collaboration members with a secure space to share unpublished or nonpublic research, fostering collaborative efforts through integrated Google Docs and Python Plotty for shared graphing work. In essence, this ambitious project endeavors to bridge the gap between complex scientific knowledge and public understanding, enhance collaboration among researchers, and serve as a dynamic and inclusive platform for sharing and advancing the state-of-the-art in Muon Catalyzed Fusion and Accelerators.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Vectorlike leptons: Muon g - 2 anomaly, lepton flavor violation, Higgs boson decays, and lepton nonuniversality

Here, we discuss the Standard Model (SM) with one family of vectorlike (VL) leptons, which couple to all three families of the SM leptons. We study the constraints on this model coming from the heavy-charged lepton mass bound, electroweak precision data, the muon anomalous magnetic moment, lepton flavor violation, Higgs boson decay constraints, and a recently measured lepton nonuniversality observable, R K * 0 , along with R K . We find that the strongest constraints are coming from the muon g - 2 , R μ μ = Γ ( h → μ μ ) / Γ ( h → μ μ ) SM , R γ γ and BR ( μ → e γ ) . While VL leptons couple to all three families of the SM leptons, the ratio of electron-VL to muon-VL coupling is constrained to be 〈 λ e / λ μ 〉 ≲ 10 - 4 . We also find that this model cannot fit the lepton nonuniversality discrepancies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Muon reconstruction performance of the ATLAS detector in proton–proton collision data at √s=13 TeV

This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at √s=13 TeV in 2015. Using a large sample of J/ψ → μμ and Z → μμ decays from 3.2 fb -1 of pp collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations. Furthermore, the reconstruction efficiency is measured to be close to 99% over most of the covered phase space (|η| < 2.5 and 52.2 , the p T resolution for muons from Z → μμ decays is 2.9% while the precision of the momentum scale for low-p T muons from J/ψ → μμ decays is about 0.2% .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Chapter 5: Bright muon beams and muon colliders

The muon collider offers a path toward high-energy, high-luminosity lepton collisions that extends beyond the expected reach of electron-positron colliders and would be competitive in physics reach with proton colliders at the highest energies. Nonetheless, several challenging elements of muon collider technology must be more fully addressed to achieve a maturity level commensurate with linear colliders. In this chapter, the potential benefits of a muon collider in terms of cost, sustainability and timescale are outlined. The major remaining technical challenges are described and an R&D programme is outlined. This programme, assuming suitable funding, will enable the next Update of the European Strategy for Particle Physics to make informed decisions regarding the future R&D path for lepton colliders.

43 PARTICLE ACCELERATORS↗

Measurement of the Muon Magnetic Anomaly $\boldsymbol{a}_{\boldsymbol{\mu}}$ in the Muon $\boldsymbol{g-2}$ Experiment at Fermilab

The Fermilab Muon g-2 experiment measures the muon anomalous magnetic moment with high precision. Together with recent improvements on the theory front, the first results of the experiment confirm the long-standing discrepancy between the experimental measurements and the Standard Model predictions. The observed value of $a_{\mu}({\textrm{FNAL}})=116\,592\,040(54)\times 10^{-11}(\text{0.46 ppm})$, combined with the previous experimental measurement, results in a discrepancy of $(251\pm 59)\times 10^{-11}$ with the theoretical prediction, corresponding to $4.2\sigma$. This note presents the first results, the current status and the future prospects of the Muon $g-2$ experiment at Fermilab.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Muon Sources for Particle Physics - Accomplishments of the Muon Accelerator Program

The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe (ν $\bar{e}$ ) and ν $\bar{μ}$ ) (ν μ ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent

43 PARTICLE ACCELERATORS↗

Muon Anomalous Precession Frequency Measurement Using Lead Fluoride Calorimeters in the Muon g-2 Experiment

aThe Standard Model (SM) of particle physics has been strikingly successful in explaining a wide range of physical phenomena and almost all experimental results. One of the most significant discrepancies at present is the anomalous magnetic moment $a_\mu$=(g−2)/2 of the muon, which was measured by the E821 collaboration at BNL in 2004 to be more than three-standard-deviation greater than the SM prediction. Various models beyond SM physics have been proposed to explain this discrepancy, but the key to resolving this tension remains a more precise measurement of $a_{\mu}$. The Muon g-2 collaboration at Fermilab aims to measure $a_{\mu}$ with a precision goal of 140 parts per billion, a fourfold improvement over BNL's result. If the central values of the experimental result and the theoretical prediction remain unchanged, the discrepancy will exceed seven standard deviations which a clear indication of physics beyond SM. In this poster, preliminary results from th e ongoing physics data taking will be presented, especially on the measurement of the muon anomalous precession frequency using lead fluoride calorimeters. Energy calibration and timing alignment procedures of calorimeter channels will also be described, and their impact on high-level analyses will be discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The Fermilab Muon $g-2$ Straw Tracking Detectors, Internal Tracker Alignment, and the Muon EDM Measurement

The $g-2$ experiment successfully completed its second data taking period (Run-2) between March and July 2019, with the analysis of Run-1 and Run-2 data currently proceeding. The final goal of the experiment is to determine the muon magnetic anomaly, $a_{\mu}=\frac{g-2}{2}$, to a precision of 140 ppb. Essential to reducing the systematic uncertainty on $a_{\mu}$ through measurements of the muon beam profile are the in-vacuum straw tracking detectors. A crucial prerequisite to obtaining accurate distributions of the beam profile is the internal alignment of the trackers, which is described here, along with the resulting beam distributions. This paper also discusses an additional measurement that will be made using the trackers: setting a new limit on the electric dipole moment (EDM) of the muon, producing a world-leading measurement.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Cosmic-muon characterization and annual modulation measurement with Double Chooz detectors

A study on cosmic muons has been performed for the two identical near and far neutrino detectors of the Double Chooz experiment, placed at ∼120 and ∼300 m.w.e. underground respectively, including the corresponding simulations using the MUSIC simulation package. This characterization has allowed us to measure the muon flux reaching both detectors to be (3.64 ± 0.04) × 10{sup −4} cm{sup −2}s{sup −1} for the near detector and (7.00 ± 0.05) × 10{sup −5} cm{sup −2}s{sup −1} for the far one. The seasonal modulation of the signal has also been studied observing a positive correlation with the atmospheric temperature, leading to an effective temperature coefficient of α {sub T} = 0.212 ± 0.024 and 0.355 ± 0.019 for the near and far detectors respectively. These measurements, in good agreement with expectations based on theoretical models, represent one of the first measurements of this coefficient in shallow depth installations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Physical applications of muon catalysis: Muon capture in hydrogen

Results: of theoretical and experimental research on capture of negative muons in hydrogen are reported with an emphasis on the accompanying phenomenon of muon catalysis in hydrogen and subtleties of the experimental method. A conclusion is drawn that precise determination of the capture rate is important for refining the standard model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Muon flux measurements at the davis campus of the sanford underground research facility with the majorana demonstrator veto system

We report the first measurement of the muon flux underground at the Davis Campus of the Sanford Underground Research Facility at the 4850 foot level. Measurements were done with the Majorana Demonstrator veto system arranged in two different configurations. Both results are in agreement within statistical accuracy. The measured flux is (4.08+-0.19) x 10 -9 muons/cm/2. We compare our results with previous calculations.

Abgrall, N.↗

The calorimeter system of the new muon g -2 experiment at Fermilab

The electromagnetic calorimeter for the new muon ( g −2) experiment at Fermilab will consist of arrays of PbF 2 Čerenkov crystals read out by large-area silicon photo-multiplier (SiPM) sensors. We report here the requirements for this system, the achieved solution and the results obtained from a test beam using 2.0–4.5 GeV electrons with a 28-element prototype array.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Muon g-2 reconstruction and analysis framework for the muon anomalous precession frequency

The Muon g-2 experiment at Fermilab, with the aim to measure the muon anomalous magnetic moment to an unprecedented level of 140~ppb, has started beam and detector commissioning in Summer 2017. To deal with incoming data projected to be around tens of petabytes, a robust data reconstruction and analysis chain based on Fermilab's art event-processing framework is developed. Herein, I report the current status of the framework, together with its novel features such as multi-threaded algorithms for online data quality monitor (DQM) and fast-turnaround operation (nearline). Performance of the framework during the commissioning run is also discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Measurement of space charge effects in the MicroBooNE LArTPC using cosmic muons

Large liquid argon time projection chambers (LArTPCs), especially those operating near the surface, are susceptible to space charge effects. In the context of LArTPCs, the space charge effect is the build-up of slow-moving positive ions in the detector primarily due to ionization from cosmic rays, leading to a distortion of the electric field within the detector. This effect leads to a displacement in the reconstructed position of signal ionization electrons in LArTPC detectors ("spatial distortions"), as well as to variations in the amount of electron-ion recombination experienced by ionization throughout the volume of the TPC. We present techniques that can be used to measure and correct for space charge effects in large LArTPCs by making use of cosmic muons, including the use of track pairs to unambiguously pin down spatial distortions in three dimensions. Finally, the performance of these calibration techniques are studied using both Monte Carlo simulation and MicroBooNE data, utilizing a UV laser system as a means to estimate the systematic bias associated with the calibration methodology.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗