Wed·Mar 15, 2023Wednesday·March 15, 2023

1. 01*

   The Qweak High Performance LH2 Target

   J. Brock🇺🇸 · S. Covrig Dusa🇺🇸 · J. Dunne🇺🇸 · C. Keith🇺🇸 · D. Meekins🇺🇸 · J. Pierce🇺🇸 · G.R. Smith🇺🇸 · A. Subedi🇺🇸

   A high-power liquid hydrogen target was built for the Jefferson Lab Qweak experiment, which measured the tiny parity-violating asymmetry in $\vec{e}$p scattering at an incident energy of 1.16 GeV, and a Q${}^2=0.025$ GeV${}^2$. To achieve the luminosity of $1.7\times 10^{39}$ cm${}^{-2}$ s${}^{-1}$, a 34.5 cm-long target was used with a beam current of 180 $\mu$A. The ionization energy-loss deposited by the beam in the target was 2.1 kW. The target temperature was controlled to within $\pm$0.02 K and the target noise (density fluctuations) near the experiment's beam helicity-reversal rate of 960 Hz was only 53 ppm. The 58 liquid liter target achieved a head of 11.4 m (7.6 kPa) and a mass flow of 1.2 $\pm$ 0.3 kg/s (corresponding to a volume flow of 17.4 $\pm$ 3.8 l/s) at the nominal 29 Hz rotation frequency of the recirculating centrifugal pump. We describe aspects of the design, operation, and performance of this target, the highest power LH2 target ever used in an electron scattering experiment to date.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·4 citations
2. 02*

   Investigating timing properties of modern digitizers utilizing interpolating CFD algorithms and the application to digital fast-timing lifetime measurement

   A. Harter · M.Weinert🇩🇪 · L. Knafla🇩🇪 · J.-M. Régis🇩🇪 · A. Esmaylzadeh · M. Ley🇩🇪 · J. Jolie🇩🇪

   The performance of two implementations of digital real-time interpolating constant fraction discriminator algorithms with respect to fast-timing lifetime measurements are investigated. The implementations integrated in two different digitizers were evaluated in terms of the effects of tuning parameters of the digital CFDs and the influence of different input amplitudes on the time resolution and time walk characteristics. Reference is made to the existing analog standard of fast-timing techniques. The study shows, that the timing performance of both modules is comparable to established fast-timing setups using analog constant fraction discriminators, but with the added benefit of digital processing. Both digitizer modules were found to be highly effective and user-friendly instruments for modern fast-timing requirements.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·9 citations
3. 03*

   Probing cold nuclear matter with energy correlators

   Kyle Devereaux🇺🇸 · Wenqing Fan🇺🇸 · Weiyao Ke🇺🇸 · Kyle Lee🇺🇸 · Ian Moult🇺🇸

   The future electron-ion collider (EIC) will produce the first-ever high energy collisions between electrons and a wide range of nuclei, opening a new era in the study of cold nuclear matter. Quarks and gluons produced in these collisions will propagate through the dense nuclear matter of nuclei, imprinting its structure into subtle correlations in the energy flux of final state hadrons. In this article, we apply recent developments from the field of jet substructure, namely the energy correlator observables, to decode these correlations and provide a new window into nuclear structure. The energy correlators provide a calibrated probe of the scale dependence of vacuum quantum chromodynamics (QCD), enabling medium modifications to be imaged and interpreted as a function of scale. Using the eHIJING parton shower to simulate electron-nucleus collisions, we demonstrate that the size of the nucleus is imprinted as an angular scale in the correlators, with a magnitude that is visible for realistic EIC kinematics. We can observe the size difference between the proposed EIC nuclear targets ${}^3$He, ${}^4$He, ${}^{12}$C, ${}^{40}$Ca, ${}^{64}$Cu, ${}^{197}$Au, and ${}^{238}$U, showing that the energy correlators can image femtometer length scales using asymptotic energy flux. Our approach offers a unified view of jet substructure across collider experiments, and provides numerous new theoretical tools to unravel the complex dynamics of QCD in extreme environments, both hot and cold.

   ↳ hep-phhep-exnucl-exnucl-thPRC(2025)·55 citations

* 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.