We present the simultaneous measurement of the interaction rates $R_{pp}$, $R_{\mathrm{Be}}$, $R_{pep}$ of $pp$, ${}^7\mathrm{Be}$, and $pep$ solar neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19–2.93) MeV with particular attention to details of the analysis methods. This result was obtained by analyzing 1291.51 days of Borexino Phase-II data, collected after an extensive scintillator purification campaign. Using counts per day $(\mathrm{cpd})/100\mathrm{ton}$ as unit, we find $R_{pp}=134\pm 10(\mathrm{stat}{)}_{-10}^{+6}(\mathrm{sys})$, $R_{Be}=48.3\pm 1.1(\mathrm{stat}{)}_{-0.7}^{+0.4}(\mathrm{sys})$; and $R_{pep}^{\mathrm{HZ}}=2.43\pm 0.36(\mathrm{stat}{)}_{-0.22}^{+0.15}(\mathrm{sys})$ assuming the interaction rate $R_{\mathrm{CNO}}$ of CNO-cycle (Carbon, Nitrogen, Oxigen) solar neutrinos according to the prediction of the high metallicity standard solar model, and $R_{pep}^{\mathrm{LZ}}=2.65\pm 0.36(\mathrm{stat}{)}_{-0.24}^{+0.15}(\mathrm{sys})$ according to that of the low metallicity model. An upper limit $R_{\mathrm{CNO}}<8.1\mathrm{cpd}/100\mathrm{ton}$ (95% C.L.) is obtained by setting in the fit a constraint on the ratio $R_{pp}/R_{pep}$ ($47.7\pm 0.8\mathrm{cpd}/100\mathrm{ton}$ or $47.5\pm 0.8\mathrm{cpd}/100\mathrm{ton}$ according to the high or low metallicity hypothesis).

This paper presents a comprehensive geoneutrino measurement using the Borexino detector, located at Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The analysis is the result of 3262.74 days of data between December 2007 and April 2019. The paper describes improved analysis techniques and optimized data selection, which includes enlarged fiducial volume and sophisticated cosmogenic veto. The reported exposure of $(1.29\pm 0.05)\times {10}^{32}\mathrm{protons}\times \mathrm{year}$ represents an increase by a factor of two over a previous Borexino analysis reported in 2015. By observing ${52.6}_{-8.6}^{+9.4}(\mathrm{stat}{)}_{-2.1}^{+2.7}(\mathrm{sys})$ geoneutrinos (68% interval) from ${}^{238}\mathrm{U}$ and ${}^{232}\mathrm{Th}$, a geoneutrino signal of ${47.0}_{-7.7}^{+8.4}({\text{stat})}_{-1.9}^{+2.4}(\mathrm{sys})$ TNU with ${}_{-17.2}^{+18.3}\%$ total precision was obtained. This result assumes the same Th/U mass ratio as found in chondritic CI meteorites but compatible results were found when contributions from ${}^{238}\mathrm{U}$ and ${}^{232}\mathrm{Th}$ were both fit as free parameters. Antineutrino background from reactors is fit unconstrained and found compatible with the expectations. The null-hypothesis of observing a geoneutrino signal from the mantle is excluded at a 99.0% C.L. when exploiting detailed knowledge of the local crust near the experimental site. Measured mantle signal of ${21.2}_{-9.0}^{+9.5}(\mathrm{stat}{)}_{-0.9}^{+1.1}(\mathrm{sys})$ TNU corresponds to the production of a radiogenic heat of ${24.6}_{-10.4}^{+11.1}\mathrm{TW}$ (68% interval) from ${}^{238}\mathrm{U}$ and ${}^{232}\mathrm{Th}$ in the mantle. Assuming 18% contribution of ${}^{40}\mathrm{K}$ in the mantle and ${8.1}_{-1.4}^{+1.9}\mathrm{TW}$ of total radiogenic heat of the lithosphere, the Borexino estimate of the total radiogenic heat of the Earth is ${38.2}_{-12.7}^{+13.6}\mathrm{TW}$, which corresponds to the convective Urey ratio of ${0.78}_{-0.28}^{+0.41}$. These values are compatible with different geological predictions, however there is a $\sim 2.4\sigma$ tension with those Earth models which predict the lowest concentration of heat-producing elements in the mantle. In addition, by constraining the number of expected reactor antineutrino events, the existence of a hypothetical georeactor at the center of the Earth having power greater than 2.4 TW is excluded at 95% C.L. Particular attention is given to the description of all analysis details which should be of interest for the next generation of geoneutrino measurements using liquid scintillator detectors.

The ${}^{17}\mathrm{O}(p,\alpha ){}^{14}\mathrm{N}$ reaction plays a key role in various astrophysical scenarios, from asymptotic giant branch stars to classical novae. It affects the synthesis of rare isotopes such as ${}^{17}\mathrm{O}$ and ${}^{18}\mathrm{F}$, which can provide constraints on astrophysical models. A new direct determination of the $E_R=64.5\mathrm{keV}$ resonance strength performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) accelerator has led to the most accurate value to date $\omega \gamma =10.0\pm 1.4_{\mathrm{stat}}\pm 0.7_{\mathrm{syst}}\mathrm{neV}$, thanks to a significant background reduction underground and generally improved experimental conditions. The (bare) proton partial width of the corresponding state at $E_x=5672\mathrm{keV}$ in ${}^{18}\mathrm{F}$ is ${\mathrm{\Gamma }}_p=35\pm 5_{\mathrm{stat}}\pm 3_{\mathrm{syst}}\mathrm{neV}$. This width is about a factor of 2 higher than previously estimated, thus leading to a factor of 2 increase in the ${}^{17}\mathrm{O}(p,\alpha ){}^{14}\mathrm{N}$ reaction rate at astrophysical temperatures relevant to shell hydrogen burning in red giant and asymptotic giant branch stars. The new rate implies lower ${}^{17}\mathrm{O}/{}^{16}\mathrm{O}$ ratios, with important implications on the interpretation of astrophysical observables from these stars.

The ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle affects the synthesis of the elements between ${}^{20}\mathrm{Ne}$ and ${}^{27}\mathrm{Al}$ in asymptotic giant branch stars and novae. The ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. At proton energies below 400 keV, only upper limits exist in the literature for the resonance strengths. Previous reaction rate evaluations differ by large factors. In the present work, the first direct observations of the ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ resonances at 156.2, 189.5, and 259.7 keV are reported. Their resonance strengths are derived with 2%–7% uncertainty. In addition, upper limits for three other resonances are greatly reduced. Data are taken using a windowless ${}^{22}\mathrm{Ne}$ gas target and high-purity germanium detectors at the Laboratory for Underground Nuclear Astrophysics in the Gran Sasso laboratory of the National Institute for Nuclear Physics, Italy, taking advantage of the ultralow background observed deep underground. The new reaction rate is a factor of 20 higher than the recent evaluation at a temperature of 0.1 GK, relevant to nucleosynthesis in asymptotic giant branch stars.