High-precision electron-capture QQ value measurement of 111^{111}In for electron-neutrino mass determination

A precise determination of the ground state $^{111}$In ($9/2^+$) electron capture to ground state of $^{111}$Cd ($1/2^+$) $Q$ value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture $Q$ value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for $^{111}$Cd was used to determine whether the four states are energetically allowed for a potential ultra-low $Q$-value $\beta^{}$ decay or electron-capture decay. Our results confirm that the excited states of 866.60(6) keV with spin-parity ($J^\pi$) of 3/2$^{+}$ and 864.8(3) keV with $J^\pi$ = 3/2$^{+}$ are ruled out due to their deduced electron-capture $Q$ value being smaller than 0 keV at the level of around 20$\sigma$ and 50$\sigma$, respectively. Electron-capture decays to the excited states at 853.94(7) keV ($J^\pi$ = 7/2$^+$) and 855.6(10) keV ($J^\pi$ = 3/2$^+$), are energetically allowed with $Q$ values of 3.69(19) keV and 2.0(10) keV, respectively. The allowed decay transition $^{111}$In (9/2$^{+}$) $\rightarrow$$^{111}$Cd (7/2$^{+}$), with a $Q$ value of 3.69(19) keV, is a potential a new candidate for neutrino-mass measurements by future EC experiments featuring new powerful detection technologies. The results show that the indium level $2p_{1/2}$ for this decay branch leads to a significant increase in the number of EC events in the energy region sensitive to the electron neutrino mass

High-precision electron-capture QQ value measurement of 111^{111}In for electron-neutrino mass determination

A precise determination of the ground state $^{111}$In ($9/2^+$) electron capture to ground state of $^{111}$Cd ($1/2^+$) $Q$ value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture $Q$ value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for $^{111}$Cd was used to determine whether the four states are energetically allowed for a potential ultra-low $Q$-value $\beta^{}$ decay or electron-capture decay. Our results confirm that the excited states of 866.60(6) keV with spin-parity ($J^\pi$) of 3/2$^{+}$ and 864.8(3) keV with $J^\pi$ = 3/2$^{+}$ are ruled out due to their deduced electron-capture $Q$ value being smaller than 0 keV at the level of around 20$\sigma$ and 50$\sigma$, respectively. Electron-capture decays to the excited states at 853.94(7) keV ($J^\pi$ = 7/2$^+$) and 855.6(10) keV ($J^\pi$ = 3/2$^+$), are energetically allowed with $Q$ values of 3.69(19) keV and 2.0(10) keV, respectively. The allowed decay transition $^{111}$In (9/2$^{+}$) $\rightarrow$$^{111}$Cd (7/2$^{+}$), with a $Q$ value of 3.69(19) keV, is a potential a new candidate for neutrino-mass measurements by future EC experiments featuring new powerful detection technologies. The results show that the indium level $2p_{1/2}$ for this decay branch leads to a significant increase in the number of EC events in the energy region sensitive to the electron neutrino mass

159^{159}Dy electron-capture: a strong new candidate for neutrino mass determination

International audienceThe ground state to ground state electron-capture Q value of Dy159 (3/2-) has been measured directly using the double Penning trap mass spectrometer JYFLTRAP. A value of 364.73(19) keV was obtained from a measurement of the cyclotron frequency ratio of the decay parent Dy159 and the decay daughter Tb159 ions using the novel phase-imaging ion-cyclotron resonance technique. The Q values for allowed Gamow-Teller transition to 5/2- and the third-forbidden unique transition to 11/2+ state with excitation energies of 363.5449(14) keV and 362.050(40) keV in Tb159 were determined to be 1.18(19) keV and 2.68(19) keV, respectively. The high-precision Q value of transition 3/2-→5/2- from this work, revealing itself as the lowest electron-capture Q value, is used to unambiguously characterize all the possible lines that are present in its electron-capture spectrum. We performed atomic many-body calculations for both transitions to determine electron-capture probabilities from various atomic orbitals and found an order of magnitude enhancement in the event rates near the end point of energy spectrum in the transition to the 5/2- nuclear excited state, which can become very interesting once the experimental challenges of identifying decays into excited states are overcome. The transition to the 11/2+ state is strongly suppressed and found unsuitable for measuring the neutrino mass. These results show that the electron-capture in the Dy159 atom, going to the 5/2- state of the Tb159 nucleus, is a new candidate that may open the way to determine the electron-neutrino mass in the sub-eV region by studying electron-capture. Further experimental feasibility studies, including coincidence measurements with realistic detectors, will be of great interest

Potential additional indicators for pacemaker requirement in isolated congenital atrioventricular block.

Contains fulltext : 49246.pdf (publisher's version ) (Closed access)Low heart rate is the predominantly used indication for pacemaker intervention in patients with isolated congenital atrioventricular block (CAVB). The aim of this study was to compare the difference in heart rates recorded with ECG and Holter monitoring between paced (PM) and nonpaced (NPM) patients with isolated CAVB before pacemaker implantation to identify additional predictors for future PM need. Retrospective evaluation of atrial and ventricular rates (electrocardiography) and minimal and maximal (Holter) heart rates in 129 CAVB patients prior to PM implantation (n = 93) was performed, and results are expressed in V adjusted for age and sex. The average V score for the atrial rate was 0.51 (n = 50) in the PM group and 0.60 (n = 22) in the NPM group (not-significant). The average z score for the ventricular (average) rate was -0.91 (n = 83) in the PM group and -0.93 (n = 33) in the NPM group (not-significant). Minimal heart rate was -0.94 (n = 61) in the PM group and -0.86 (n = 25) in the NPM group (not significant). Maximal heart rate was -0.96 (n = 61) in the PM group and -0.95 (n = 26) in the NPM group (not significant). Initial recordings of the average heart rate and the minimal and maximal heart rate recorded during Holter monitoring do not seem to predict future pacemaker need in patients with CAVB. Studies with exercise stress tests are needed to confirm these findings