Mon·Aug 23, 2021Monday·August 23, 2021

1. 01*

   Mulan: a part-per-million measurement of the muon lifetime and determination of the Fermi constant

   Robert Carey🇺🇸 · Tim Gorringe🇺🇸 · David Hertzog🇺🇸

   The part-per-million measurement of the positive muon lifetime and determination of the Fermi constant by the MuLan experiment at the Paul Scherrer Institute is reviewed. The experiment used an innovative, time-structured, surface muon beam and a near-4pi, finely-segmented, plastic scintillator positron detector. Two in-vacuum muon stopping targets were used: a ferromagnetic foil with a large internal magnetic field, and a quartz crystal in a moderate external magnetic field. The experiment obtained a muon lifetime 2 196 980.3(2.2) ps (1.0 ppm) and a Fermi constant 1.166 378 7(6) 10^-5 GeV^-2 (0.5 ppm). The thirty-fold improvement in the muon lifetime has proven valuable for precision measurements in nuclear muon capture and the commensurate improvement in the Fermi constant has proven valuable for precision tests of the standard model.

   nucl-exhep-exphysics.ins-detSciPost Phys.Proc.(2021)·8 citations
2. 02*

   Studying hadronization at LHCb

   Sookhyun Lee🇺🇸

   LHCb is a fully instrumented forward spectrometer with particle identification and muon reconstruction covering the pseudorapidity ($\eta$) range from 2 to 5. Its full jet reconstruction capability makes the LHCb experiment a suitable venue to explore jet substructure observables, particularly formation of hadrons and heavy quarkonia resonances inside jets. This contribution presents a brief overview of ongoing research program and discusses recent results on non-identified charged hadron distributions in Z-tagged jets and charmonium distributions within jets. Future works towards furthering the knowledge of hadronizion are also discussed.

   ↳ hep-exnucl-exSciPost Phys.Proc.(2022)·0 citations
3. 03*

   The Effect of Cosmic Ray Muon Momentum Measurement for Monitoring Shielded Special Nuclear Materials

   Junghyun Bae🇺🇸 · Stylianos Chatzidakis🇺🇸

   Recently, cosmic ray muons have been considered as a potential high energy radiation probe for monitoring and interrogation of dense, well-shielded special nuclear materials (SNM). Due to their high-penetrative nature, cosmic ray muons can easily penetrate shielded nuclear materials with minimal absorption and with leaving the target objects intact. However, despite the potential benefits from using cosmic ray muons for SNM monitoring, their widespread application has been limited for various reasons, including relatively low cosmic ray muon flux at sea level and the difficulty of measuring muon momentum in the field which can increase resolution and reduce measurement time. In this work, we explore in detail the effect of cosmic ray muon momentum measurement, focusing specifically on SNM monitoring applications. Three different types of SNMs (HEU, LEU, and Pu) surrounded by lead shielding with five different thicknesses (0, 5, 10, 20, and 30 cm), are analyzed using Monte Carlo simulation for three momentum measurement resolution levels (perfect, limited, and absent). 1000 muons were generated in the simulation which translates to 4 minutes of measurement time for a standard cargo container. We found that it is possible to identify and separate HEU, LEU, and Pu with high accuracy (> 3 s.d.) when using muon momentum measurement (perfect and limited) even when 30 cm-thick lead shielding was used. Currently, it is not possible to identify or separate the SNMs with 30 cm thick lead shielding without muon momentum knowledge. Our results show that the effect of measuring muon momentum can be significant and can result in reduced measurement times by a factor of 3 to 4 and/or improved monitoring and imaging resolution.

   ↳ physics.ins-detnucl-exProceedings of the INMM & ESARDA Joint Vi…·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.