Karol Lang

Probing New Physics Models of Neutrinoless Double Beta Decay with SuperNEMO

The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double β decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double β decay by measuring the decay half-life and the electron angular and energy distributions.

Investigation of double beta decay of 100Mo to excited states of 100Ru

Double beta decay of 100Mo to the excited states of daughter nuclei has been studied using a 600 cm3 low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic 100Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of 100Mo. The half-life for the two-neutrino double beta decay of 100Mo to the excited View the MathML source01+ state in 100Ru is measured to be T1/2=[7.5±0.6(stat)±0.6(syst)]⋅1020 yrT1/2=[7.5±0.6(stat)±0.6(syst)]⋅1020 yr. For other (0ν+2ν)(0ν+2ν) transitions to the View the MathML source21+, View the MathML source22+, View the MathML source02+, View the MathML source23+ and View the MathML source03+ levels in 100Ru, limits are obtained at the level of ∼(0.25-1.1)⋅1022 yr∼(0.25-1.1)⋅1022 yr.

New experimental limits on KL0--> microe and KL0-->ee branching ratios.

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.

Latest results from the NEMO-3 experiment and status of SuperNEMO

The NEMO-3 experiment, designed to search for neutrinoless double beta decay, was carried out from 2003 to 2011 in the Modane Underground Laboratory in the Frejus Tunnel under the French-Italian Alps. The detector employed thin isotopic foils surrounded by a drift chamber and scintillator blocks to reconstruct topology, energy, and timing features of nuclear decays. This multi-observable technique offers a powerful means not only to identify double beta decays but also to reject background events mostly due to natural radioactivity. NEMO-3 employed seven different isotopes to construct foils, with most notable mass of 100Mo of 6.9 kg and 82Se of 0.93 kg. Data from the entire running period are currently being analyzed but NEMO-3 has already achieved the best-to-date results on half-lives of all seven isotopes and has reported lower limits on neutrinoless double beta half-lives which can be translated to the most stringent upper limit on the effective neutrino mass.

Measurement of the Double Beta Decay Half-life of 130 Te with the NEMO-3 Detector

We report results from the NEMO-3 experiment based on an exposure of 1275 days with 661 g of (130)Te in the form of enriched and natural tellurium foils. The ββ decay rate of (130)Te is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T(½)(2ν) = [7.0 ± 0.9(stat) ± 1.1(syst)] × 10(20) yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay.

MINOS: Long Baseline Search for Neutrino Oscillations at Fermilab

MINOS — a long baseline two-detector search for neutrino oscillations mixing until now studied only with atmospheric neutrinos.

New experimental limits onKL0→μe andKL0→ee branching ratios

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.

New Experimental Limits on

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.