New limits on double-beta decay of $$^{190}$$Pt and $$^{198}$$Pt

Abstract

A search for double-beta decay of $$^{190}$$ 190 Pt and $$^{198}$$ 198 Pt with emission of $$\gamma $$ 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 $$^{190}$$ 190 Pt relative to different channels and modes of the decays were set on the level of $$\lim T_{1/2}\sim 10^{14}$$ lim T 1 / 2 ∼ 10 14 –$$10^{16}$$ 10 16 year. A possible exact resonant $$0\nu KN$$ 0 ν K N transition to the 1,2 1326.9 keV level of $$^{190}$$ 190 Os is limited for the first time as $$T_{1/2} \ge 2.5 \times 10^{16}$$ T 1 / 2 ≥ 2.5 × 10 16 year. A new lower limit on the double-beta decay of $$^{198}$$ 198 Pt to the first excited level of $$^{198}$$ 198 Hg was set as $$T_{1/2} \ge 3.2\times 10^{19}$$ T 1 / 2 ≥ 3.2 × 10 19 year, one order of magnitude higher than the limit obtained in the previous experiment.

Updated and novel limits on double beta decay and dark matter-induced processes in platinum

“…or excited state (exc. ), and corresponding X-ray energy, detection efficiency, and experimental limits (90% C.L) derived here and compared to [ 6 ] Transition Decay mode [keV] Experimental [ years] This work [ 6 ] 2K (g.s.) 63.0 0.175 KL (g.s.)…”

“…This method is limited to detecting the low-energy deexcitation ’s that accompany DBD transitions to excited states of daughter nuclides [ 3 – 8 ]. However this approach has also met some experimental difficulties due to the reduced efficiency of registration from non-optimized geometry of the experiment and self-absorption in the dense samples [ 6 – 8 ].…”

“…Both and , which possess several DBD modes, have been investigated previously using Pt metal pieces of various thickness and geometries [ 6 , 11 ]. While searches using this method were able to set limits on the half-life of years, they suffer from low detection efficiency due to self-absorption of the low energy ’s within the Pt sample itself.…”

“…In the work presented here, data from a Pt foil sample using the new thin foil technique was analyzed to search for the various DBD modes. Comparable half-life limits are placed to [ 6 ] of years with less exposure due to the increase in detection efficiency. While these results, obtained with -g-target mass are not competitive to those obtained in tonne-scale searches, it is useful to set limits with a diverse range of target isotopes, even through benchtop experiments, to aid in theoretical modeling as half-life predictions are obtained through model-dependent nuclear matrix element calculations.…”

Non-accelerator particle physics in Ukraine

“…В Інституті ядерних досліджень НАН України ведуться дослідження властивостей нейтрино і слабкої взаємодії у подвійному бетарозпаді атомних ядер [43][44][45][46][47][48], пошуки гіпотетичних частинок та ефектів за межами СМ [49,50], дослідження рідкісних та гіпотетичних ядерних розпадів [51][52][53][54], вимірювання потоків нейтрино від Сонця та інших джерел [55][56][57], розроблення детекторів для пошуків темної матерії [58,59], реєстрації когерентного розсіяння нейтрино та інших рідкісних процесів [60][61][62].…”