Wed·Feb 9, 2022Wednesday·February 9, 2022

1. 01*

   Measurement of $\psi (2S)$ nuclear modification at backward and forward rapidity in $p$$+$$p$, $p$$+$Al, and $p$$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV

   U.A. Acharya · C. Aidala · Y. Akiba · M. Alfred · V. Andrieux · N. Apadula · H. Asano · B. Azmoun · V. Babintsev · N.S. Bandara · K.N. Barish · S. Bathe and 305 other authors

   Suppression of the $J/\psi$ nuclear-modification factor has been seen as a trademark signature of final-state effects in large collision systems for decades. In small systems, the nuclear modification was attributed to cold-nuclear-matter effects until the observation of strong differential suppression of the $\psi (2S)$ state in $p/d$$+$$A$ collisions suggested the presence of final-state effects. Results of $J/\psi$ and $\psi (2S)$ measurements in the dimuon decay channel are presented here for $p$$+$$p$, $p$$+$Al, and $p$$+$Au collision systems at $\sqrt{s_{{}_{NN}}}=200$ GeV. The results are predominantly shown in the form of the nuclear-modification factor, $R_{pA}$, the ratio of the $\psi (2S)$ invariant yield per nucleon-nucleon collision in collisions of proton on target nucleus to that in $p$$+$$p$ collisions. Measurements of the $J/\psi$ and $\psi (2S)$ nuclear-modification factor are compared with shadowing and transport-model predictions, as well as to complementary measurements at Large-Hadron-Collider energies.

   nucl-exhep-exPRC(2022)·35 citations
2. 02*

   Direct measurement of the ionization quenching factor of nuclear recoils in germanium in the keV energy range

   A. Bonhomme🇩🇪 · H. Bonet🇩🇪 · C. Buck🇩🇪 · J. Hakenmüller🇩🇪 · G. Heusser🇩🇪 · T. Hugle🇩🇪 · M. Lindner🇩🇪 · W. Maneschg🇩🇪 · R. Nolte🇩🇪 · T. Rink🇩🇪 · E. Pirovano🇩🇪 · H. Strecker🇩🇪

   This article reports the measurement of the ionization quenching factor in germanium for nuclear recoil energies between 0.4 and 6.3 keV${}_{nr}$. Precise knowledge of this factor in this energy range is relevant for coherent elastic neutrino-nucleus scattering and low mass dark matter searches with germanium-based detectors. Nuclear recoils were produced in a thin high-purity germanium target with a very low energy threshold via irradiation with monoenergetic neutron beams. The energy dependence of the ionization quenching factor was directly measured via kinematically constrained coincidences with surrounding liquid scintillator based neutron detectors. The systematic uncertainties of the measurements are discussed in detail. With measured quenching factors between 0.16 and 0.23 in the [0.4, 6.3] keV${}_{nr}$ energy range, the data are compatible with the Lindhard theory with a parameter $k$ of 0.162 $\pm$ 0.004 (stat+sys).

   ↳ physics.ins-dethep-exnucl-exEPJC(2022)·81 citations
3. 03*

   Design and Performance of the GERDA Low-Background Cryostat for Operation in Water

   K. T. Knöpfle🇩🇪 · B. Schwingenheuer (Max-Planck-Institut für Kernphysik, Heidelberg)🇩🇪

   In searching for the neutrinoless double-beta decay of ${}^{76}$Ge the GERmanium Detector Array (GERDA) experiment at the INFN Laboratori Nazionali del Gran Sasso has achieved an unprecedented low background of well below 10${}^{-3}$ cts/(keV$\cdot$kg$\cdot$yr) in the region of interest. It has taken advantage of the first realization of a novel shielding concept based on a large cryostat filled with a liquid noble gas that is immersed in a water tank. The germanium detectors are operated without encapsulation in liquid argon. Argon and water shield the environmental background from the laboratory and the cryostat construction materials to a negligible level. The same approach has been adopted in the meantime by various experiments. This paper provides an overview of the design and operating experience of the 64 m${}^3$ liquid argon cryostat and its associated infrastructure. The discussion includes the challenging safety issues associated with the operation of a large cryostat in a water tank.

   ↳ physics.ins-detnucl-exJINST·11 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.