Thu·Jun 16, 2022Thursday·June 16, 2022

1. 01*

   The Decay Q Value of Neutrinoless Double Beta Decay

   Dongming Mei🇺🇸 · Wenzhao Wei🇺🇸

   An earlier publication "The implication of the atomic effects in neutrinoless double beta (0$\nu \beta \beta$) decay" written by Mei and Wei has motivated us to compare the decay Q value ($Q_{\beta \beta }$) derived from the decay of the parent nucleus to the daughter nucleus with the two ejected beta particles in the final state to the $Q_{\beta \beta }$ directly derived from the decay of the initial neutral atom to the final state of double-ionized daughter ion with the two ejected beta particles in the final state. We show that the results are the same, which is the mass-energy difference ($\Delta M{c}^2$) subtracted by the total difference of the atomic electron binding energy ($\Delta E_b$) between the ground states of initial and final neutral atoms. We demonstrate that $\Delta M{c}^2$ is the sum of $Q_{\beta \beta }$ and the atomic relaxation energy ($\Delta E_b$) of the atomic structure after the decay. Depending on the atomic relaxation time, the release of the atomic binding energy may not come together with the energy deposition of the two ejected beta particles.

   nucl-exnucl-thNPA(2023)·2 citations
2. 02*

   Hyperfine fields at ${}^{66}$Ga, ${}^{67,69}$Ge implanted into iron and gadolinium hosts at 6 K, and applications to g-factor measurements

   T. J. Gray🇦🇺 · A. E. Stuchbery🇦🇺 · B. J. Coombes🇦🇺 · J. T. H. Dowie🇦🇺 · M. S. M. Gerathy🇦🇺 · T. Kibedi🇦🇺 · G. J. Lane🇦🇺 · B. P. McCormick🇦🇺 · A. J. Mitchell🇦🇺 · M. W. Reed🇺🇸

   Isomers in ${}^{66}$Ga, ${}^{67}$Ge, and ${}^{69}$Ge were recoil-implanted into ferromagnetic hosts of iron and gadolinium at $\approx 6$~K, and the hyperfine magnetic fields were determined by Time Differential Perturbed Angular Distribution (TDPAD) measurements. The hyperfine field strengths at $\approx 6$~K are compared to the results of previous higher-temperature measurements and the amplitudes of the $R(t)$ functions are compared to empirical expectations. The results show that gadolinium can be a suitable host for high-precision in-beam $g$-factor measurements. The results of new $g$-factor measurements for isomers in ${}^{66}$Ga and ${}^{67}$Ge are $g{(}^{66}$Ga$,7^{-})=+0.126(4)$, supporting a $[{\pi }_{f5/2}\otimes \nu g_{9/2}{]}_{7^{-}}$ configuration assignment, and $g{(}^{67}$Ge$,{\frac{9}{2}}^{+})=-0.1932(22)$, derived from a new measurement of the ratio $g{(}^{67}\mathrm{Ge})/g{(}^{69}\mathrm{Ge})=0.869(9)$. These values are in agreement with previous results. The $R(t)$ amplitudes indicate that the nuclear alignment produced in the isomeric states was significantly lower than the empirically expected $\sigma /I\approx 0.35$.

   nucl-exPRC(2020)·4 citations
3. 03*

   Precision tests of the nonlinear mode coupling of anisotropic flow via high-energy collisions of isobars

   Jiangyong Jia🇺🇸 · Giuliano Giacalone🇩🇪 · Chunjian Zhang🇺🇸

   Valuable information on the dynamics of expanding fluids can be inferred from the response of such systems to perturbations in their initial geometry. We apply this technique in high-energy ${}^{96}$Ru+${}^{96}$Ru and ${}^{96}$Zr+${}^{96}$Zr collisions to scrutinize the expansion dynamics of the quark-gluon plasma, where the initial geometry perturbations are sourced by the differences in deformations and radial profiles between ${}^{96}$Ru and ${}^{96}$Zr, and the collective response is captured by the change in anisotropic flow $V_n$ between the two collision systems. Using a transport model, we analyze how the nonlinear coupling between lower-order flow harmonics $V_2$ and $V_3$ to the higher-order flow harmonics $V_4$ and $V_5$, expected to scale as $V_{4\mathrm{NL}}={\chi }_4{V}_2^2$ and $V_{5\mathrm{NL}}={\chi }_5{V}_2{V}_3$, gets modified as one moves from ${}^{96}$Ru+${}^{96}$Ru to ${}^{96}$Zr+${}^{96}$Zr systems. We find that these scaling relations are valid to high precision: variations of order 20\% in $V_{4\mathrm{NL}}$ and $V_{5\mathrm{NL}}$ due to differences in quadrupole deformation, octupole deformation, and nuclear skin modify ${\chi }_4$ and ${\chi }_5$ by about 1--2\%. Percent-level deviations are however larger than the expected experimental uncertainties and could be measured. Therefore, collisions of isobars with different nuclear structures are a unique tool to isolate subtle nonlinear effects in the expansion of the quark-gluon plasma that would be otherwise impossible to access in a single collision system.

   ↳ nucl-thhep-phnucl-exChin.Phys.Lett.(2023)·24 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.