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1. Reduction of spectroscopic overlap across the $Z=8$ shell in neutron-rich nuclei

   https://doi.org/10.1103/PhysRevC.109.054325  

   Redpath, T; Guèye, P; Baumann, T; Brown, B A; Cunningham, A; DeYoung, P A; Frank, N; Hoffman, C R; Kuchera, A N; Godoy, B Monteagudo; et al (May 2024, Physical Review C)

   Zhang, Lin (Ed.)

   The recent discovery and spectroscopic measurements of ${}^{27}\mathrm{O}$and ${}^{28}\mathrm{O}$suggests the disappearance of the $N=20$shell structure in these neutron-rich oxygen isotopes. We measured one- and two-proton removal cross sections from ${}^{27}\mathrm{F}$and ${}^{29}\mathrm{Ne}$, respectively, extracting spectroscopic factors and comparing them to shell model overlap functions coupled with eikonal reaction model calculations. The invariant mass technique was used to reconstruct the two-body ( ${}^{24}\mathrm{O}+n$) and three-body ( ${}^{24}\mathrm{O}+2n$) decay energies from knockout reactions of ${}^{27}\mathrm{F}$(106.2 MeV/u) and ${}^{29}\mathrm{Ne}$(112.8 MeV/u) beams impinging on a ${}^9\mathrm{Be}$target. The one-proton removal from ${}^{27}\mathrm{F}$strongly populated the ground state of ${}^{26}\mathrm{O}$and the extracted cross section of $3.4_{-1.5}^{+0.3}$mb agrees with eikonal model calculations that are normalized by the shell model spectroscopic factors and account for the systematic reduction factor observed for single nucleon removal reactions within the models used. For the two-proton removal reaction from ${}^{29}\mathrm{Ne}$an upper limit of 0.08 mb was extracted for populating states in ${}^{27}\mathrm{O}$decaying though the ground state of ${}^{26}\mathrm{O}$. The measured upper limit for the population of the ground state of ${}^{26}\mathrm{O}$in the two-proton removal reaction from ${}^{29}\mathrm{Ne}$indicates a significant difference in the underlying nuclear structure of ${}^{27}\mathrm{F}$and ${}^{29}\mathrm{Ne}$. Published by the American Physical Society2024 

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2. Asymptotic normalization coefficients for $\alpha +{}^{12}\mathrm{C}$ synthesis and the $S$ factor for ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ radiative capture

   https://doi.org/10.1103/PhysRevC.110.055803  

   Mukhamedzhanov, A M; deBoer, R J; Irgaziev, B F; Blokhintsev, L D; Kadyrov, A S; Savin, D A (November 2024, Physical Review C)

   : The ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$reaction, determining the survival of carbon in red giants, is of interest for nuclear reaction theory and nuclear astrophysics. A specific feature of the ${}^{16}\mathrm{O}$nuclear structure is the presence of two subthreshold bound states, (6.92 MeV, $2^{+}$) and (7.12 MeV, $1^{-}$), that dominate the behavior of the low-energy $S$factor. The strength of these subthreshold states is determined by their asymptotic normalization coefficients (ANCs), which need to be known with high accuracy. : The objective of this research is to examine how the subthreshold and ground-state ANCs impact the low-energy $S$factor, especially at the key astrophysical energy of $300\mathrm{keV}$. The $S$factors are calculated within the framework of the $R$-matrix method using the code. Our total $S$factor takes into account the $E1$and $E2$transitions to the ground state of ${}^{16}\mathrm{O}$including the interference of the subthreshold and higher resonances, which also interfere with the corresponding direct captures, and cascade radiative captures to the ground state of ${}^{16}\mathrm{O}$through four subthreshold states: $0_2^{+},3^{-},2^{+}$, and $1^{-}$. To evaluate the impact of subthreshold ANCs on the low-energy $S$factor, we employ two sets of the ANCs. The first selection, which offers higher ANC values, is attained through the extrapolation process [Blokhintsev , ]. The set with low ANC values was employed by deBoer []. A detailed comparison of the $S$factors at the most effective astrophysical energy of 300 keV is provided, along with an investigation into how the ground-state ANC affects this $S$factor. : The contribution to the total $E1$and $E2S$factors from the corresponding subthreshold resonances at $300\mathrm{keV}$are $(71–74)\%$and $(102–103)\%$, respectively. The correlation of the uncertainties of the subthreshold ANCs with the $E1$and $E2S\left(300\mathrm{keV}\right)$factors is found. The $E1$transition of the subthreshold resonance $1^{-}$does not depend on the ground-state ANC but interferes constructively with a broad $(9.585\mathrm{MeV};1^{-})$resonance giving (for the present subthreshold ANC) an additional $26\%$contribution to the total $E1S\left(300\mathrm{keV}\right)$factor. Interference of the $E2$transition through the subthreshold resonance $2^{+}$with direct capture is almost negligible for small ground-state ANC of $58{\mathrm{fm}}^{-1/2}$. However, its interference with direct capture for higher ground-state ANC of $337{\mathrm{fm}}^{-1/2}$is significant and destructive, contributing $-27\%$. The low-energy $S_{E2}\left(300\mathrm{keV}\right)$factor experiences a smaller increase when both subthfreshold and the ground-state ANCs rise together due to their anticorrelation, compared to when only the subthreshold ANCs increase. Published by the American Physical Society2024 

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3. Direct measurement of the ${}^{3}P_0$ clock state natural lifetime in ${}^{87}\mathrm{Sr}$

   https://doi.org/10.1103/f6pt-flnt  

   Dolde, Jonathan; Ganapathy, Dhruva; Zheng, Xin; Ma, Shuo; Beloy, Kyle; Kolkowitz, Shimon (August 2025, Physical Review A)

   Optical lattice clocks based on the narrow $(5s^2){}^{1}S_0\text{−}\left(5s5p\right){}^{3}P_0$transition in neutral strontium (Sr) are among the most precise and accurate measurement devices in existence. Although this transition is completely forbidden by selection rules, state mixing from the hyperfine interaction in ${}^{87}\mathrm{Sr}$provides a weakly allowed transition that can be coherently driven with practical clock laser intensities. While the coherent interrogation times of optical clocks are typically set by the linewidth of the probe laser, this limitation can be overcome in synchronous differential comparisons between ensembles. In such measurements the natural lifetime of the ${}^{1}S_0–{}^{3}P_0$clock transition becomes the fundamental limiting factor to the duration of a single run of the experiment. However, a direct measurement of the decay rate of the clock excited state is quite challenging due to the competing effects of other loss channels such as Raman scattering, inelastic collisions, and atom loss due to background gas. In this work, we monitor the decay of Sr atoms trapped in an optical lattice and initialized in the ${}^{3}P_0$state. By making measurements of high and low density ensembles of both ${}^{87}\mathrm{Sr}$and ${}^{88}\mathrm{Sr}$across varying lattice trap depths, we isolate radiative decay, which accounts for a significant fraction of the observed decays at low depths. We obtain a natural radiative decay lifetime of ${167}_{-40}^{+79}$s for the ${}^{3}P_0$clock state in ${}^{87}\mathrm{Sr}$, a value that is consistent with previously reported measurements and theoretical predictions. We also introduce an additional measurement scheme that involves repeated measurements of the ground-state population within a single experimental sequence, validating our model and the consistency of the measured rates. We expect that the techniques introduced in this work are applicable to lifetime measurements of long-lived metastable states in other atoms and ions used for clocks and quantum computing. The results presented in this work inform performance estimates of proposed gravitational wave detectors and long-baseline atom interferometers making use of ${}^{87}\mathrm{Sr}$. 

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4. Strength measurements of the $E_{\mathrm{R}}^{\mathrm{lab}}=647$ and 1842 keV resonances in the ${}^{40}\mathrm{Ca}(p,\gamma ){}^{41}\mathrm{Sc}$ reaction and their relevance in novae nucleosynthesis

   https://doi.org/10.1103/PhysRevC.111.025804  

   Sidhu, R S; deBoer, R J; Görres, J; Wiescher, M; Koros, J; Manukyan, K; Matney, M; McDonaugh, J; Picciotto, V; Sanchez, A T; et al (February 2025, Physical Review C)

   Here we report on the direct measurement of the resonance strengths of the $E_{\mathrm{R}}^{\mathrm{lab}}=647\mathrm{keV}$and 1842 keV resonances in the ${}^{40}\mathrm{Ca}(p,\gamma ){}^{41}\mathrm{Sc}$reaction. At novae temperatures, $0.2<T_9<0.7$, the ${}^{40}\mathrm{Ca}(p,\gamma ){}^{41}\mathrm{Sc}$reaction is governed by the low energy resonance at $E_{\mathrm{R}}^{\mathrm{lab}}=647\mathrm{keV}$, whereas the $E_{\mathrm{R}}^{\mathrm{lab}}=1842\mathrm{keV}$resonance serves as a normalization standard for nuclear reaction experiments within the astrophysically relevant energy range. For the $E_{\mathrm{R}}^{\mathrm{lab}}=647\mathrm{keV}$resonance, we obtain a resonance strength $\omega \gamma =(2.51\pm 0.{09}_{\mathrm{stat}}\pm 0.{22}_{\mathrm{syst}})\mathrm{meV}$, with an uncertainty a factor of 2.5 smaller than the previous direct measurement value. For the $E_{\mathrm{R}}^{\mathrm{lab}}=1842\mathrm{keV}$resonance, we obtain a resonance strength $\omega \gamma =(0.148\pm 0.{006}_{\mathrm{stat}}\pm 0.{013}_{\mathrm{syst}})\mathrm{eV}$, which is consistent with previous studies but deviates by $2\sigma$from the most recent measurement. Our results suggest ${}^{40}\mathrm{Ca}$to be a strong waiting point in the nucleosynthesis path of oxygen-neon (ONe) novae. Published by the American Physical Society2025 

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5. Observation of the Open-Charm Tetraquark Candidate $T_{cs0}^{*}(2870{)}^0$ in the $B^{-}\to D^{-}{D}^0{K}_S^0$ Decay

   https://doi.org/10.1103/PhysRevLett.134.101901  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (March 2025, Physical Review Letters)

   An amplitude analysis of $B^{-}\to D^{-}{D}^0{K}_S^0$decays is performed using proton-proton collision data, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A resonant structure of spin-parity $0^{+}$is observed in the $D^0{K}_S^0$invariant-mass spectrum with a significance of $5.3\sigma$. The mass and width of the state, modeled with a Breit-Wigner line shape, are determined to be $2883\pm 11\pm 8\mathrm{MeV}/c^2$and ${87}_{-47}^{+22}\pm 17\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second systematic. These properties and the quark content are consistent with those of the open-charm tetraquark candidate $T_{cs0}^{*}(2870{)}^0$observed previously in the $D^{+}{K}^{-}$final state of the $B^{-}\to D^{-}{D}^{+}{K}^{-}$decay. This result confirms the existence of the $T_{cs0}^{*}(2870{)}^0$state in a new decay mode. The $T_{cs1}^{*}(2900{)}^0$state, reported in the $B^{-}\to D^{-}{D}^{+}{K}^{-}$decay, is also searched for in the $D^0{K}_S^0$invariant-mass spectrum of the $B^{-}\to D^{-}{D}^0{K}_S^0$decay, without finding evidence for it. © 2025 CERN, for the LHCb Collaboration2025CERN 

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