Fri·Jun 3, 2022Friday·June 3, 2022

1. 01*

   $\beta$-nuclear-recoil correlation from ${}^6$He decay in a laser trap

   P. Müller🇺🇸 · Y. Bagdasarova🇺🇸 · R. Hong🇺🇸 · A. Leredde🇫🇷 · K.G. Bailey🇺🇸 · X. Fléchard🇫🇷 · A. García🇺🇸 · B. Graner🇺🇸 · A. Knecht🇨🇭 · O. Naviliat-Cuncic🇫🇷 · T.P. O'Connor🇺🇸 · M.G. Sternberg🇺🇸 and 4 other authors

   We report the first precise measurement of a $\beta$-recoil correlation from a radioactive noble gas (${}^6\mathrm{He}$) confined via a magneto-optical trap. The measurement is motivated by the search for exotic tensor-type contributions to the charged weak current. Interpreted as tensor currents with right-handed neutrinos, the measurements yield: $|C_T/C_A{|}^2\le 0.022$ (90\% C.L.). On the other hand, for left-handed neutrinos the limits are $0.007<C_T/C_A<0.111$~(90\%\ C.L.). The sensitivity of the present measurement is mainly limited by experimental uncertainties in determining the time response properties and the distance between the atom cloud and the micro-channel plate used for recoil ion detection.

   nucl-exPRL(2022)·19 citations
2. 02*

   Nuclear Spectroscopy of Radioactive Strontium-94

   Jack Pellew

   Traditionally, the production of neutron-rich nuclei in laboratories has been impossible. However, with the accelerator facilities now available at the ATLAS facility of Argonne National Laboratory, there is now a unique opportunity for the study of such nuclei. By studying how the Rb-94 nucleus decays and releases energy, there has been a potential to update the currently accepted information, with further applications in nuclear astrophysics and nuclear reactor dynamics.

   nucl-exphysics.acc-ph0 citations
3. 03*

   Strong constraints on jet quenching in centrality-dependent $p$+Pb collisions at 5.02 TeV from ATLAS

   ATLAS Collaboration

   Jet quenching is the process of color-charged partons losing energy via interactions with quark-gluon plasma droplets created in heavy-ion collisions. The collective expansion of such droplets is well described by viscous hydrodynamics. Similar evidence of collectivity is consistently observed in smaller collision systems, including $pp$ and $p$+Pb collisions. In contrast, while jet quenching is observed in Pb+Pb collisions, no evidence has been found in these small systems to date, raising fundamental questions about the nature of the system created in these collisions. The ATLAS experiment at the Large Hadron Collider has measured the yield of charged hadrons correlated with reconstructed jets in 0.36 nb${}^{-1}$ of $p$+Pb and 3.6 pb${}^{-1}$ of $pp$ collisions at 5.02 TeV. The yields of charged hadrons with $p_{\mathrm{T}}^{\mathrm{ch}}>0.5$ GeV near and opposite in azimuth to jets with $p_{\mathrm{T}}^{\mathrm{jet}}>30$ or $60$ GeV, and the ratios of these yields between $p$+Pb and $pp$ collisions, $I_{p\mathrm{Pb}}$, are reported. The collision centrality of $p$+Pb events is categorized by the energy deposited by forward neutrons from the struck nucleus. The $I_{p\mathrm{Pb}}$ values are consistent with unity within a few percent for hadrons with $p_{\mathrm{T}}^{\mathrm{ch}}>4$ GeV at all centralities. These data provide new, strong constraints which preclude almost any parton energy loss in central $p$+Pb collisions.

   nucl-exhep-exPRL(2023)·54 citations
4. 04*

   Technique for the measurement of intrinsic pulse-shape discrimination for organic scintillators using tagged neutrons

   N. Mauritzson🇸🇪 · K.G. Fissum🇸🇪 · J.R.M. Annand🇬🇧 · H. Perrey🇸🇪 · R.J.W. Frost🇸🇪 · R. Al Jebali · A. Backis · R. Hall-Wilton🇸🇪 · K. Kanaki🇸🇪 · V. Maulerova-Subert🇸🇪 · C. Maurer · F. Messi🇸🇪 · E. Rofors🇸🇪

   Fast-neutron/gamma-ray pulse-shape discrimination has been performed for the organic liquid scintillators NE 213A and EJ 305 using a time-of-flight based neutron-tagging technique and waveform digitization on an event-by-event basis. Gamma-ray sources and a Geant4-based simulation were used to calibrate the scintillation-light yield. The difference in pulse shape for the neutron and gamma-ray events was analysed by integrating selected portions of the digitized waveform to produce a figure-of-merit for neutron/gamma-ray separation. This figure-of-merit has been mapped as a function of detector threshold and also of neutron energy determined from time-of-flight. It shows clearly that the well-established pulse-shape discrimination capabilities of NE 213A are superior to those of EJ 305. The extra information provided by the neutron-tagging technique has resulted in a far more detailed assessment of the pulse-shape discrimination capabilities of these organic scintillators.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2022)·5 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.