Thu·Mar 21, 2024Thursday·March 21, 2024

1. 01*

   Design, construction, and operation of a 1-ton Water-based Liquid scintillator detector at Brookhaven National Laboratory

   X. Xiang🇺🇸 · G. Yang🇺🇸 · S. Andrade🇺🇸 · M. Askins🇺🇸 · D.M. Asner🇺🇸 · A. Baldoni🇺🇸 · D. Cowen🇺🇸 · M.V. Diwan🇺🇸 · S. Gokhale🇺🇸 · S. Hans🇺🇸 · J. Jerome🇺🇸 · G. Lawley🇺🇸 and 11 other authors

   Water-based liquid scintillators (WbLS) are attractive neutrino detector materials because they allow us to tune the ratio of the Cherenkov and scintillation signals. Using WbLS large-scale neutrino experiments can benefit from both directional reconstruction and enhanced low-energy efficiency. Furthermore, broadening the science capability of such materials by metal doping may be better suited for water based liquid scintillators. We recently constructed and commissioned a 1-ton WbLS detector with good photosensor coverage and a capable data acquisition system. We intend to use this flexible detector system as a testbed for WbLS R&D. In this paper we give an overview of the 1-ton system and provide some early analysis results.

   ↳ physics.ins-dethep-exnucl-exJINST(2024)·11 citations
2. 02*

   Beam test of n-type Silicon pad array detector at PS CERN

   Sawan🇮🇳 · M. Bregant🇮🇳 · J. L. Bouly🇫🇷 · O. Bourrion🇫🇷 · A. van den Brink🇳🇱 · T. Chujo🇯🇵 · C. Krug🇧🇷 · L. Kumar🇮🇳 · V. K. S. Kashyap🇮🇳 · A. Ghimouz🇨🇭 · M. Inaba🇯🇵 · T. Isidori🇺🇸 and 12 other authors

   This work reports the testing of a Forward Calorimeter (FoCal) prototype based on an n-type Si pad array detector at the CERN PS accelerator. The FoCal is a proposed upgrade in the ALICE detector operating within the pseudorapidity range of 3.2 < $\eta$ < 5.8. It aims to measure direct photons, neutral hadrons, vector mesons, and jets for the study of gluon saturation effects in the unexplored region of low momentum fraction x ($\sim 10^{-5}-10^{-6}$). The prototype is a $8\times 9$ n-type Si pad array detector with each pad occupying one cm${}^2$ area, fabricated on a 6-in, 325~$\pm 10\mu$m thick, and high-resistivity ($\sim$7 k$\Omega$ cm) Si wafer which is readout using HGCROCv2 chip. The detector is tested using pion beams of energy 10~GeV and electron beams of energy 1-5~GeV. The measurements of the Minimum Ionizing Particle (MIP) response of pions and the shower profiles of electrons are reported.

   ↳ physics.ins-dethep-exnucl-exJINST(2024)·6 citations
3. 03*

   Absence of strong CP violation

   Gerrit Schierholz🇩🇪

   Quantum Chromodynamics admits a CP-violating contribution to the action, the $\theta$ term, which is expected to give rise to a nonvanishing electric dipole moment of the neutron. Despite intensive search, no CP violations have been found in the strong interaction. This puzzle is referred to as the strong CP problem. There is evidence that CP is conserved in the confining theory, to the extent that color charges are totally screened for $\theta >0$ at large distances. It is not immediately obvious that this implies a vanishing dipole moment though. With this Letter I will close the gap. It is shown that in the infinite volume hadron correlation functions decouple from the topological charge, expressed in terms of the zero modes. The reason is that hadrons have a limited range of interaction, while the density of zero modes vanishes with the inverse root of the volume, thus reducing the probability of finding a zero mode in the vicinity to zero. This implies that CP is conserved in the strong interaction.

   ↳ hep-phhep-lathep-thnucl-ex+1J.Phys.G(2025)·18 citations
4. 04*

   Opportunities at the Sanford Underground Research Facility

   Jaret Heise

   The Sanford Underground Research Facility (SURF) has been operating for more than 15 years as an international facility dedicated to advancing compelling multidisciplinary underground scientific research in rare-process physics, as well as offering research opportunities in other disciplines. SURF laboratory facilities include a Surface Campus as well as campuses at the 4850-foot level (1490 m, 4300 m.w.e.) that host a range of significant physics experiments, including the LUX-ZEPLIN (LZ) dark matter experiment and the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment. The CASPAR nuclear astrophysics accelerator completed the first phase of operation and is planning for the second phase beginning in 2024. SURF is also home to the Long-Baseline Neutrino Facility (LBNF) that will host the international Deep Underground Neutrino Experiment (DUNE). SURF offers world-class service, including an ultralow background environment, low-background assay capabilities, and electroformed copper is produced at the facility. SURF is preparing to increase underground laboratory space. Plans are advancing for construction of new large caverns (nominally 100m L x 20m W x 24m H) on the 4850L (1485 m, 4100 m.w.e.) on the timeframe of next generation experiments (~2030). SURF plans to leverage existing advisory and community committees as well as engage the underground science community to inform plans for future laboratory space.

   ↳ hep-exastro-ph.IMnucl-exphysics.ins-detPoS(2024)·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.