Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the 2$ ubetabeta$ decay half-life of $^{150}$Nd and a search for 0$ ubetabeta$ decay processes with the full exposure from the NEMO-3 detector
138
0
0.0
(
0
)
Authors
NEMO-3 Collaboration: R. Arnold
Ask ChatGPT about the research
No Arabic abstract
We present results from a search for neutrinoless double-$beta$ ($0 ubetabeta$) decay using 36.6 g of the isotope $^{150}$Nd with data corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We construct a complete background model for this isotope, including a measurement of the two-neutrino double-$beta$ decay half-life of $T^{2 u}_{1/2}=$[9.34 $pm$ 0.22 (stat.) $^{+0.62}_{-0.60}$ (syst.)]$times 10^{18}$ y for the ground state transition, which represents the most precise result to date for this isotope. We perform a multivariate analysis to search for zeronu decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for zeronu decay is observed, we derive lower limits on half-lives for several mechanisms involving physics beyond the Standard Model. The observed lower limit, assuming light Majorana neutrino exchange mediates the decay, is $T^{0 u}_{1/2} >$ 2.0 $times 10^{22}$ y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of $langle m_{ u} rangle$ $<$ 1.6 - 5.3 eV..
rate research
Read More
The NEMO-3 experiment measured the half-life of the $2 ubetabeta$ decay and searched for the $0 ubetabeta$ decay of $^{116}$Cd. Using $410$ g of $^{116}$Cd installed in the detector with an exposure of $5.26$ y, ($4968pm74$) events corresponding to the $2 ubetabeta$ decay of $^{116}$Cd to the ground state of $^{116}$Sn have been observed with a signal to background ratio of about $12$. The half-life of the $2 ubetabeta$ decay has been measured to be $ T_{1/2}^{2 u}=[2.74pm0.04mbox{(stat.)}pm0.18mbox{(syst.)}]times10^{19}$ y. No events have been observed above the expected background while searching for $0 ubetabeta$ decay. The corresponding limit on the half-life is determined to be $T_{1/2}^{0 u} ge 1.0 times 10^{23}$ y at the $90$ % C.L. which corresponds to an upper limit on the effective Majorana neutrino mass of $langle m_{ u} rangle le 1.4-2.5$ eV depending on the nuclear matrix elements considered. Limits on other mechanisms generating $0 ubetabeta$ decay such as the exchange of R-parity violating supersymmetric particles, right-handed currents and majoron emission are also obtained.
The NEMO-3 experiment at the Modane Underground Laboratory has investigated the double-$beta$ decay of $^{48}{rm Ca}$. Using $5.25$ yr of data recorded with a $6.99,{rm g}$ sample of $^{48}{rm Ca}$, approximately $150$ double-$beta$ decay candidate events have been selected with a signal-to-background ratio greater than $3$. The half-life for the two-neutrino double-$beta$ decay of $^{48}{rm Ca}$ has been measured to be $T^{2 u}_{1/2},=,[6.4, ^{+0.7}_{-0.6}{rm (stat.)} , ^{+1.2}_{-0.9}{rm (syst.)}] times 10^{19},{rm yr}$. A search for neutrinoless double-$beta$ decay of $^{48}{rm Ca}$ yields a null result and a corresponding lower limit on the half-life is found to be $T^{0 u}_{1/2} > 2.0 times 10^{22},{rm yr}$ at $90%$ confidence level, translating into an upper limit on the effective Majorana neutrino mass of $< m_{betabeta} > < 6.0 - 26$ ${rm eV}$, with the range reflecting different nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right-handed currents.
We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-$beta$ decay of $^{150}$Nd using a total exposure of $0.19$ kg$cdot$y recorded with the NEMO-3 detector at the Modane Underground Laboratory (LSM). We find no evidence of this decay and set lower limits on the half-life in the range $T_{1/2}>(1.1-3.2)times10^{21}$ y at the $90%$ CL, depending on the model used for the kinematic distributions of the emitted electrons.
We measured two-neutrino double beta decay of $^{130}$Te using an exposure of 300.7 kg$cdot$yr accumulated with the CUORE detector. Using a Bayesian analysis to fit simulated spectra to experimental data, it was possible to disentangle all the major background sources and precisely measure the two-neutrino contribution. The half-life is in agreement with past measurements with a strongly reduced uncertainty: $T^{2 u}_{1/2} = 7.71^{+0.08}_{-0.06}mathrm{(stat.)}^{+0.12}_{-0.15}mathrm{(syst.)}times10^{20}$ yr. This measurement is the most precise determination of the $^{130}$Te 2$ ubetabeta$ decay half-life to date.
This Letter reports results from the NEMO-3 experiment based on an exposure of 1275 days with 661g of 130Te in the form of enriched and natural tellurium foils. The double beta decay rate of 130Te is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T1/2 = (7.0 +/- 0.9(stat) +/- 1.1(syst)) x 10^{20} yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
