Lead (Pb) isotopes can provide key information to address fundamental geologic problems related to the formation and evolution of rocky planets. The Pb isotope system supports a diversity of applications, as it provides access to information on magma sources as well as geologic age. Consequently, a wide range of analytical techniques, data validation and interpretation strategies have been advanced across a range of Pb isotope studies. Given the multiple different Pb isotope pairs, reflecting different decay rates and ultimate parental isotope concentrations, Pb isotopes have been viewed as one of the more challenging isotope systems to comprehend. Here we provide an overview of the various analytical and interpretative approaches, for this system, and highlight their respective strengths in the context of applications, such as magma source tracking and model age determination. A discussion of different methods to determine magma source parameters (e.g., U/Pb ratio and model age) is presented, along with recommendations for data validation and reporting. A checklist for recommended data and metadata to report for Pb isotopes is provided. The aim of this contribution is to provide a framework that enables a robust interpretation of Pb isotope signatures, promoting data transparency and comparison across different analytical approaches.

Lead isotopes are a powerful geochemical tracer and a popular tool applied across a broad range of scientific fields, e.g., earth sciences, archaeology, and forensic sciences. Here we present a Pb isotope dataset collected from 232 igneous samples, spanning a ca. 2.3 million km2 area in southeastern Australia, and over 3 billion years of Earth history. This contribution provides a range of isotopic maps showing the spatial variability of Pb isotopes (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), magma source U/Pb and Th/U, and model ages. The samples selected for this study encompass U- and Th-poor media (i.e., K-feldspar), and U- and Th-bearing sampling media (i.e., whole-rock), providing a temporally and spatially resolved image of U and Th distribution in the crust, and their influence on crustal Pb through radiogenic ingrowth. This dataset has the potential to benefit a wide variety of different disciplines and is an important resource for addressing earth science questions ranging from unravelling crustal differentiation and architecture, through tracing magma source U- and Th-enrichment, to mineral deposit genesis.

The current experiments searching for neutrinoless double- β ( 0νββ ) decay also collect large statistics of Standard Model allowed two-neutrino double- β ( 2νββ ) decay events. These can be used to search for Beyond Standard Model (BSM) physics via 2νββ decay spectral distortions. 100Mo has a natural advantage due to its relatively short half-life, allowing higher 2νββ decay statistics at equal exposures compared to the other isotopes. We demonstrate the potential of the dual read-out bolometric technique exploiting a 100Mo exposure of 1.47 kg × years, acquired in the CUPID-Mo experiment at the Modane underground laboratory (France). We set limits on 0νββ decays with the emission of one or more Majorons, on 2νββ decay with Lorentz violation, and 2νββ decay with a sterile neutrino emission. In this analysis, we investigate the systematic uncertainty induced by modeling the 2νββ decay spectral shape parameterized through an improved model, an effect never considered before. This work motivates searches for BSM processes in the upcoming CUPID experiment, which will collect the largest amount of 2νββ decay events among the next-generation experiments.

Abstract The current experiments searching for neutrinoless double- $$\beta $$ β ( $$0\nu \beta \beta $$ 0 ν β β ) decay also collect large statistics of Standard Model allowed two-neutrino double- $$\beta $$ β ( $$2\nu \beta \beta $$ 2 ν β β ) decay events. These can be used to search for Beyond Standard Model (BSM) physics via $$2\nu \beta \beta $$ 2 ν β β decay spectral distortions. 100Mo has a natural advantage due to its relatively short half-life, allowing higher $$2\nu \beta \beta $$ 2 ν β β decay statistics at equal exposures compared to the other isotopes. We demonstrate the potential of the dual read-out bolometric technique exploiting a 100Mo exposure of 1.47 kg $$\times $$ × years, acquired in the CUPID-Mo experiment at the Modane underground laboratory (France). We set limits on $$0\nu \beta \beta $$ 0 ν β β decays with the emission of one or more Majorons, on $$2\nu \beta \beta $$ 2 ν β β decay with Lorentz violation, and $$2\nu \beta \beta $$ 2 ν β β decay with a sterile neutrino emission. In this analysis, we investigate the systematic uncertainty induced by modeling the $$2\nu \beta \beta $$ 2 ν β β decay spectral shape parameterized through an improved model, an effect never considered before. This work motivates searches for BSM processes in the upcoming CUPID experiment, which will collect the largest amount of $$2\nu \beta \beta $$ 2 ν β β decay events among the next-generation experiments.

Neutrinoless double beta decay (0νββ) is a yet unobserved nuclear process that would demonstrate Lepton number violation, a clear evidence of beyond standard model physics. The process two neutrino double beta decay (2νββ) is allowed by the standard model and has been measured in numerous experiments. In this Letter, we report a measurement of 2νββ decay half-life of ^{100}Mo to the ground state of ^{100}Ru of [7.07±0.02(stat)±0.11(syst)]×10^{18}  yr by the CUPID-Mo experiment. With a relative precision of ±1.6% this is the most precise measurement to date of a 2νββ decay rate in ^{100}Mo. In addition, we constrain higher-order corrections to the spectral shape, which provides complementary nuclear structure information. We report a novel measurement of the shape factor ξ_{3,1}=0.45±0.03(stat)±0.05(syst) based on a constraint on the ratio of higher-order terms from theory, which can be reliably calculated. This is compared to theoretical predictions for different nuclear models. We also extract the first value for the effective axial vector coupling constant obtained from a spectral shape study of 2νββ decay.

search for double-beta decay of ^190 Pt and ^198 Pt with emission of γ -ray quanta was realized at the HADES underground laboratory with a 148 g platinum sample measured by two ultralow-background HPGe detectors over 8946 h. The isotopic composition of the platinum sample has been measured with high precision using inductively coupled plasma mass spectrometry. New lower limits for the half-lives of ^190 Pt relative to different channels and modes of the decays were set on the level of lim T_1/2∼ 10^14 – 10^16 year. A possible exact resonant 0ν KN transition to the 1,2 1326.9 keV level of ^190 Os is limited for the first time as T_1/2≥ 2.5 × 10^16 year. A new lower limit on the double-beta decay of ^198 Pt to the first excited level of ^198 Hg was set as T_1/2≥ 3.2× 10^19 year, one order of magnitude higher than the limit obtained in the previous experiment.

A search for double-beta decay of $$^{190}$$ Pt and $$^{198}$$ Pt with emission of $$\gamma $$ -ray quanta was realized at the HADES underground laboratory with a 148 g platinum sample measured by two ultralow-background HPGe detectors over 8946 h. The isotopic composition of the platinum sample has been measured with high precision using inductively coupled plasma mass spectrometry. New lower limits for the half-lives of $$^{190}$$ Pt relative to different channels and modes of the decays were set on the level of $$\lim T_{1/2}\sim 10^{14}$$ – $$10^{16}$$ year. A possible exact resonant $$0\nu KN$$ transition to the 1,2 1326.9 keV level of $$^{190}$$ Os is limited for the first time as $$T_{1/2} \ge 2.5 \times 10^{16}$$ year. A new lower limit on the double-beta decay of $$^{198}$$ Pt to the first excited level of $$^{198}$$ Hg was set as $$T_{1/2} \ge 3.2\times 10^{19}$$ year, one order of magnitude higher than the limit obtained in the previous experiment.