Wed·Dec 2, 2020Wednesday·December 2, 2020

1. 01*

   Anomalies in Radioactive Decay Rates: A Bibliography of Measurements and Theory

   M. H. McDuffie🇺🇸 · P. Graham · J. L. Eppele · J. T. Gruenwald · D. Javorsek II · D. E. Krause🇺🇸 · E. Fischbach🇺🇸

   Knowledge of the decay rates (or half-lives) of radioisotopes is critical in many fields, including medicine, archeology, and nuclear physics, to name just a few. Central to the many uses of radioisotopes is the belief that decay rates are fundamental constants of nature, just as the masses of the radioisotopes themselves are. Recently, the belief that decay rates are fundamental constants has been called into question following the observation of various reported anomalies in decay rates, such as apparent periodic variations. The purpose of this bibliography is to collect in one place the relevant literature on both sides of this issue in the expectation that doing so will deepen our understanding of the available data.

   nucl-exnucl-th9 citations
2. 02*

   Comment on "First Observation of Multiple Transverse Wobbling Bands of Different Kinds in ${}^{183}$Au [Phys. Rev. Lett. 125, 132501 (2015)]"

   S. Guo🇨🇳 · C. M. Petrache🇫🇷

   In [S. Nandi et al., Phys. Rev. Lett. 125, 132501 (2020)] two transverse wobbling bands were reported in ${}^{183}$Au. The critical experimental proof for this assignment is the E2 dominated linking transitions between the wobbling and normal bands, which are supported by fitting the measured DCO ratio and polarization results. However, the uncertainties are significantly underestimated according to an analysis on the statistical error. With reasonable error, the mixing ratios cannot be exclusively decided, and the M1 dominated character cannot be excluded, indicating that the wobbling assignment is still questionable.

   nucl-ex1 citation
3. 03*

   Double beta decay results from the CUPID-0 experiment

   D. Chiesa🇮🇹 · O. Azzolini🇮🇹 · J. W. Beeman🇺🇸 · F. Bellini🇮🇹 · M. Beretta🇮🇹 · M. Biassoni🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 · S. Capelli🇮🇹 · L. Cardani🇮🇹 · E. Celi🇮🇹 · P. Carniti🇮🇹 and 34 other authors

   A convincing observation of neutrino-less double beta decay (0$\nu$DBD) relies on the possibility of operating high energy-resolution detectors in background-free conditions. Scintillating cryogenic calorimeters are one of the most promising tools to fulfill the requirements for a next-generation experiment. Several steps have been taken to demonstrate the maturity of this technique, starting from the successful experience of CUPID-0. The CUPID-0 experiment demonstrated the complete rejection of the dominant alpha background measuring the lowest counting rate in the region of interest for this technique. Furthermore, the most stringent limit on the ${}^{82}$Se 0$\nu$DBD was established running 26 ZnSe crystals during two years of continuous detector operation. In this contribution we present the final results of CUPID-0 Phase I including a detailed model of the background, the measurement of the ${}^{82}$Se 2$\nu$DBD half-life and the evidence that this nuclear transition is single state dominated.

   nucl-exPoS(2021)·3 citations
4. 04*

   Estimate of the location of the neutron drip line for calcium isotopes from an exact Hamiltonian with continuum pair correlations

   A. C. Dassie · R. M. Id Betan🇦🇷

   The eastern region of the calcium isotope chain of the nuclei chart is, nowadays, of great activity. The experimental assessment of the limit of stability is of interest to confirm or improve microscopic theoretical models. The goal of this work is to provide the drip line of the calcium isotopes from the exact solution of the pairing Hamiltonian which incorporates explicitly the correlations with the continuum spectrum of energy. The modified Richardson equations, which include correlations with the continuum spectrum of energy modeled by the continuum single particle level density, is used to solve the many-body system. Three models are used, two isospin independent models with core 40Ca and 48Ca, and one isospin dependent model. One and two-neutron separation energies and occupation probabilities for bound and continuum states are calculated from the solution of the Richardson equations. The one particle drip line is found at the nucleus 57Ca, while the two neutron drip line is found at the nucleus 60Ca from the isospin independent model and at 66Ca from the isospin dependent one.

   ↳ nucl-thnucl-exPRC(2020)·0 citations
5. 05*

   Curing the unphysical behaviour of NLO quarkonium production at the LHC and its relevance to constrain the gluon PDF at low scales

   Jean-Philippe Lansberg🇫🇷 · Melih Arslan Ozcelik🇫🇷

   We address the unphysical energy dependence of quarkonium-hadroproduction cross sections at Next-to-Leading Order (NLO) in alpha_S which we attribute to an over-subtraction in the factorisation of the collinear singularities inside the PDFs in the MSbar scheme. Such over- or under-subtractions have a limited phenomenological relevance in most of the scattering processes in particle physics. On the contrary, it is particularly harmful for P_T-integrated charmonium hadroproduction which renders a wide class of NLO results essentially unusable. Indeed, in such processes, alphaS is not so small, the PDFs are not evolved much and can be rather flat for the corresponding momentum fractions and, finally, some process-dependent NLO pieces are either too small or too large. We propose a scale-fixing criterion which avoids such an over-subtraction. We demonstrate its efficiency for eta(c,b) but also for a fictitious light elementary scalar boson. Having provided stable NLO predictions for eta(c,b) P_T-integrated cross sections, sigma^NLO(eta(Q)), and discussed the options to study eta(b) hadroproduction, we argue that their measurement at the LHC can help better determine the gluon PDF at low scales and tell whether the local minimum in conventional NLO gluon PDFs around x=0.001 at scales below 2 GeV is physical or not.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2021)·34 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.