0000000000478527
AUTHOR
V. Egorov
showing 9 related works from this author
Measurement of the double-βdecay half-life ofNd150and search for neutrinoless decay modes with the NEMO-3 detector
2009
The half-life for double-{beta} decay of {sup 150}Nd has been measured by the NEMO-3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of {sup 150}Nd, we measured the half-life for 2{nu}{beta}{beta} decay to be T{sub 1/2}{sup 2{nu}}=(9.11{sub -0.22}{sup +0.25}(stat.){+-}0.63(syst.))x10{sup 18} yr. The observed limit on the half-life for neutrinoless double-{beta} decay is found to be T{sub 1/2}{sup 0{nu}}>1.8x10{sup 22} yr at 90% confidence level. This translates into a limit on the effective Majorana neutrino mass of <4.0-6.3 eV if the nuclear deformation is taken into account. We also set limits on models involving Majoron emission, right-hand…
Measurement of the background in the NEMO 3 double beta decay experiment
2009
In the double beta decay experiment NEMO 3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO 3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.
Results of the search for neutrinoless double-βdecay inMo100with the NEMO-3 experiment
2015
The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double $\beta$ ($0\nu\beta\beta$) decay. We report final results of a search for $0\nu\beta\beta$ decays with $6.914$ kg of $^{100}$Mo using the entire NEMO-3 data set with a detector live time of $4.96$ yr, which corresponds to an exposure of 34.3 kg$\cdot$yr. We perform a detailed study of the expected background in the $0\nu\beta\beta$ signal region and find no evidence of $0\nu\beta\beta$ decays in the data. The level of observed background in the $0\nu\beta\beta$ signal region $[2.8-3.2]$ MeV is $0.44 \pm 0.13$ counts/yr/kg, and no events are obs…
Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors
2010
We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of $\rm ^{207}Bi$ and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.
Doppler-broadening of gamma rays following muon capture: search for scalar coupling
2002
Abstract A precision measurement of the 277 keV γ ray produced by capturing muons in gaseous oxygen was performed using high-resolution HPGe detectors. The Doppler-broadened shape of this line is sensitive to the possible admixture into muon capture of genuine scalar interaction. This experiment complements, in the muon sector, in principle, similar ones undertaken recently in nuclear β decay. Using a procedure discussed in earlier papers, a fit to the experimental line-shape allowed us to obtain for the recoil–gamma correlation coefficient the value of a 1 2 =0.096±0.041 (95% CL). The available evaluations of the contributing nuclear matrix elements, performed in the impulse approximation …
Search for neutrinoless double-beta decay ofMo100with the NEMO-3 detector
2014
We report the results of a search for the neutrinoless double-$\beta$ decay (0$\nu\beta\beta$) of $^{100}$Mo, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg.y, no evidence for the 0$\nu\beta\beta$ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of $T_{1/2}(0\nu\beta\beta)>1.1 \times 10^{24}$ years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the Nuclear Matrix Elements this corresponds to an upper limit on the Majorana effective neutrino mass of $ < 0.3-0.8$ eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0$…
Final results on $${}^\mathbf{82 }{\hbox {Se}}$$ 82Se double beta decay to the ground state of $${}^\mathbf{82 }{\hbox {Kr}}$$ 82Kr from the NEMO-3 e…
2018
Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay ($$2\nu \beta \beta $$ 2νββ ) half-life of $$^{82}$$ 82 Se as $$T_{\smash {1/2}}^{2\nu } \!=\! \left[ 9.39 \pm 0.17\left( \text{ stat }\right) \pm 0.58\left( \text{ syst }\right) \right] \times 10^{19}$$ T1/22ν=9.39±0.17stat±0.58syst×1019 y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is $$\left| M^{2\nu }\right| = 0.0498 \pm 0.0016$$ M2ν=0.0498±0.0016 . In addition, a search for neutrinoless double beta decay ($$0\nu \beta \beta $$ 0νββ ) using 0.93 kg of $$^{82}$$ 82 Se observed for a total of 5.25 y has been conducted and no evide…
Detailed studies of $$^{100}$$ 100 Mo two-neutrino double beta decay in NEMO-3
2019
The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $$^{100}$$ 100 Mo to the ground state of $$^{100}$$ 100 Ru, $$T_{1/2} = \left[ 6.81 \pm 0.01\,\left( \text{ stat }\right) ^{+0.38}_{-0.40}\,\left( \text{ syst }\right) \right] \times 10^{18}$$ T1/2=6.81±0.01stat-0.40+0.38syst×1018 year. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $$5\times 10^5$$ 5×105 events and a signal-to-background ratio of $$\sim $$ ∼ 80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limit…
Ordinary muon capture studies for the matrix elements in ββ decay
2019
High-purity germanium (HPGe) detectors were used to make a precise measurement of the γ-ray spectrum produced following ordinary (nonradiative) capture of negative muons by natural Se, Kr, Cd, and Sm. The measurement was repeated for isotopically enriched 48Ti, 76Se, 82Kr, 106Cd, and 150Smtargets. By investigating energy and time distributions, the lifetime of negative muons in the different isotopes was deduced. A detailed analysis of the intensity of the γ lines enabled the extraction of the relative yields of several daughter nuclei. The partial rates of (μ−,ν) capture to numerous excited levels of the 48Sc, 76As, 82Br, 106Ag, and 150Tc isotopes (considered to be virtual states of the in…