Fri·Aug 12, 2022Friday·August 12, 2022

1. 01*

   Characterization of electroless nickel-phosphorus plating for ultracold-neutron storage

   H. Akatsuka🇯🇵 · T. Andalib · B. Bell · J. Berean-Dutcher🇨🇦 · N. Bernier🇨🇦 · C.P. Bidinosti · C. Cude-Woods🇺🇸 · S.A. Currie🇺🇸 · C.A. Davis🇬🇧 · B. Franke🇨🇦 · R. Gaur · P. Giampa🇨🇦 and 42 other authors

   Electroless nickel plating is an established industrial process that provides a robust and relatively low-cost coating suitable for transporting and storing ultracold neutrons (UCN). Using roughness measurements and UCN-storage experiments we characterized UCN guides made from polished aluminum or stainless-steel tubes plated by several vendors. All electroless nickel platings were similarly suited for UCN storage with an average loss probability per wall bounce of $2.8\cdot 10^{-4}$ to $4.1\cdot 10^{-4}$ for energies between 90 neV and 190 neV, or a ratio of imaginary to real Fermi potential $\eta$ of $1.7\cdot 10^{-4}$ to $3.3\cdot 10^{-4}$. Measurements at different elevations indicate that the energy dependence of UCN losses is well described by the imaginary Fermi potential. Some special considerations are required to avoid an increase in surface roughness during the plating process and hence a reduction in UCN transmission. Increased roughness had only a minor impact on storage properties. Based on these findings we chose a vendor to plate the UCN-production vessel that will contain the superfluid-helium converter for the new TRIUMF UltraCold Advanced Neutron (TUCAN) source, achieving acceptable UCN-storage properties with $\eta =3.5(5)\cdot 10^{-4}$.

   nucl-exNucl.Instrum.Meth.A(2023)·8 citations
2. 02*

   Higher-order Proton Cumulants in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV from RHIC-STAR

   Yu Zhang (for the STAR Collaboration)🇨🇳

   In these proceedings, we present the higher-order cumulants of proton multiplicity distributions of the fixed-target (FXT) run in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 3.0 GeV. The cumulant ratios are presented as a function of centrality and collision energy. The proton cumulant ratio C4/C2 is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical point could exist at energies higher than 3 GeV if created in heavy-ion collisions.

   nucl-exhep-exActa Phys.Polon.Supp.(2023)·2 citations
3. 03*

   Femtoscopy of Proton, Light nuclei, and Strange hadrons in Au+Au Collisions at STAR

   Ke Mi (for the STAR Collaboration)🇨🇳

   In these proceedings, we present the measurements of proton, light nuclei, and strange particle with neutral kaons correlation functions in Au+Au collisions at the BES program and top RHIC energy. The experimental results will be compared with model calculations to extract the size of emitting source and the properties of final state interactions. The collision energy and centrality dependence of the source size will be studied. Further, the implications for the production mechanism of light nuclei will be discussed.

   nucl-exhep-exActa Phys.Polon.Supp.(2023)·5 citations
4. 04*

   Snowmass 2021/22 Letter of Interest: A Forward Calorimeter at the LHC

   I.G. Bearden🇩🇰 · R. Bellwied🇺🇸 · V. Borshchov🇺🇦 · J. Faivre🇫🇷 · C. Furget🇫🇷 · E. Garcia-Solis🇺🇸 · M.B. Gay Ducati🇧🇷 · G. Conesa-Balbastre🇫🇷 · R. Guernane🇫🇷 · C. Loizides🇺🇸 · J. Rojo🇳🇱 · M. Płoskoń🇺🇸 and 11 other authors

   A forward electromagnetic and hadronic calorimeter (FoCal) was proposed as an upgrade to the ALICE experiment, to be installed during LS3 for data-taking in 2027--2029 at the LHC. The FoCal extends the scope of ALICE, which was designed for the comprehensive study of hot and dense partonic matter, by adding new capabilities to explore the small-$x$ parton structure of nucleons and nuclei. The primary objective of the FoCal is high-precision inclusive measurement of direct photons and jets, as well as coincident gamma-jet and jet-jet measurements, in pp and p--Pb collisions. These measurements by FoCal constitute an essential part of a comprehensive small-$x$ program at the LHC down to $x\sim 10^{-6}$ and over a large range of $Q^2$ with a broad array of complementary probes, comprising -- in addition to the photon measurements by FoCal and LHCb -- Drell-Yan and open charm measurements planned by LHCb, as well as photon-induced reactions performed by all LHC experiments.

   ↳ hep-exnucl-exphysics.ins-det2 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.