Fri·Jan 14, 2022Friday·January 14, 2022

1. 01*

   Development of a ${}^{127}$Xe calibration source for nEXO

   B. G. Lenardo🇺🇸 · C. A. Hardy🇺🇸 · R. H. M. Tsang🇺🇸 · J. C. Nzobadila Ondze🇿🇦 · A. Piepke🇺🇸 · S. Triambak🇿🇦 · A. Jamil🇺🇸 · G. Adhikari🇺🇸 · S. Al Kharusi🇨🇦 · E. Angelico🇺🇸 · I. J. Arnquist🇺🇸 · V. Belov🇨🇦 and 116 other authors

   We study a possible calibration technique for the nEXO experiment using a ${}^{127}$Xe electron capture source. nEXO is a next-generation search for neutrinoless double beta decay ($0\nu \beta \beta$) that will use a 5-tonne, monolithic liquid xenon time projection chamber (TPC). The xenon, used both as source and detection medium, will be enriched to 90% in ${}^{136}$Xe. To optimize the event reconstruction and energy resolution, calibrations are needed to map the position- and time-dependent detector response. The 36.3 day half-life of ${}^{127}$Xe and its small $Q$-value compared to that of ${}^{136}$Xe $0\nu \beta \beta$ would allow a small activity to be maintained continuously in the detector during normal operations without introducing additional backgrounds, thereby enabling in-situ calibration and monitoring of the detector response. In this work we describe a process for producing the source and preliminary experimental tests. We then use simulations to project the precision with which such a source could calibrate spatial corrections to the light and charge response of the nEXO TPC.

   ↳ physics.ins-detnucl-exJINST(2022)·4 citations
2. 02*

   History and Geography of Pentaquark Searches: Challenges and Pitfalls

   Moskov Amaryan🇺🇸

   In this paper I review the history and geography of the pentaquark searches and discuss the current situation surrounding these searches performed at different facilities around the world. The possibility of the existence of multiquark states like tetraquarks and pentaquarks was already predicted by Gell-Mann based on the Constituent Quark Model (CQM), however more than half a century efforts in a wide range of experiments led to controversial situation, when the fate of the light quark pentaquarks is almost decided to not exist. The recent LHCb results on the observation of the charm pentaquarks in the invariant mass of $pJ/\psi$ from the ${\Lambda }_b\to K^{-}pJ/\psi$ decay created a new wave of excitement and rises the question about the existence of the light pentaquarks. The main question which still remains to be clarified is whether already acquired evidences are sufficient to completely disregard the light pentaquarks and leave it out as an example of the scientific curiosity or there are still rooms for further, more dedicated efforts and scrupulous analyses to answer the question of the existence or non existence of the light pentaquarks made of $u,d$ and $s$ quarks.

   ↳ hep-exnucl-exEur.Phys.J.Plus(2022)·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.