Wed·Aug 9, 2023Wednesday·August 9, 2023

1. 01*

   Precision measurement of ${}^{65}$Zn electron-capture decays with the KDK coincidence setup

   L. Hariasz🇨🇦 · P.C.F. Di Stefano🇨🇦 · M. Stukel🇨🇦 · B.C. Rasco🇺🇸 · K.P. Rykaczewski🇺🇸 · N.T. Brewer🇺🇸 · R.K. Grzywacz🇺🇸 · E.D. Lukosi🇺🇸 · D. W. Stracener🇺🇸 · M. Mancuso🇩🇪 · F. Petricca🇩🇪 · J. Ninkovic🇩🇪 · P. Lechner (KDK Collaboration)🇩🇪

   ${}^{65}$Zn is a common calibration source, moreover used as a radioactive tracer in medical and biological studies. In many cases, $\gamma$-spectroscopy is a preferred method of ${}^{65}$Zn standardization, which relies directly on the branching ratio of $J\pi {(}^{65}\text{Zn})=5/2^{-}\to J\pi {(}^{65}\text{Cu})=5/2^{-}$ via electron capture (EC*). We measure the relative intensity of this branch to that proceeding directly to the ground state (EC${}^0$) using a novel coincidence technique, finding $I_{{\text{EC}}^0}/I_{\text{EC*}}=0.9684\pm 0.0018$. Re-evaluating the decay scheme of ${}^{65}$Zn by adopting the commonly evaluated branching ratio of $I_{{\beta }^{+}}=1.4271(7)\%$ we obtain $I_{\text{EC*}}=(50.08\pm 0.06)\%$, and I_\text{EC^0} = (48.50 \pm 0.06) \%. The associated 1115 keV gamma intensity agrees with the previously reported NNDC value, and is now accessible with a factor of ~2 increase in precision. Our re-evaluation removes reliance on the deduction of this gamma intensity from numerous measurements, some of which disagree and depend directly on total activity determination. The KDK experimental technique provides a new avenue for verification or updates to the decay scheme of ${}^{65}$Zn, and is applicable to other isotopes.

   nucl-exNucl.Data Sheets(2023)·0 citations
2. 02*

   Search for the QCD critical point by NA61/SHINE at the CERN SPS

   Haradhan Adhikary (for the NA61/SHINE Collaboration)🇵🇱

   The existence and location of the QCD critical point is an object of both experimental and theoretical studies. The comprehensive data collected by the NA61/SHINE during a two-dimensional scan in beam momentum (13A-150A GeV/c) and system size (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb) allows for a systematic search for the critical point -- a search for a non-monotonic dependence of various correlation and fluctuation observables on collision energy and size of colliding nuclei. In particular, fluctuations of particle number in transverse momentum space are studied. They are quantified by measuring the scaling behavior of factorial moments of multiplicity distributions. This contribution reviews ongoing NA61/SHINE studies to search for the critical point of the strongly interacting matter.

   nucl-ex10 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.