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Topic: Double beta decay

	Double beta decay - Wikipedia, the free encyclopedia
		In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino.
		In double beta decay two neutrons in the nuclei are converted to protons, and two electrons and two anti-neutrinos are emitted.
		In neutrinoless double beta decay the emitted neutrino is immediately absorbed (as its anti-particle) by another nucleon of the nucleus, so the total kinetic energy of the two electrons would be exactly the difference in binding energy between the initial and final state nuclei.
	en.wikipedia.org /wiki/Double_beta_decay (411 words)

	Beta decay - Wikipedia, the free encyclopedia
		In nuclear physics, beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted.
		In nature, most isotopes are beta stable, but a few exceptions exist with half-lives so long that they have not had enough time to decay since the moment of their nucleosynthesis.
		Beta decay can be considered as a perturbation as described in quantum mechanics, and thus follows Fermi's Golden Rule.
	en.wikipedia.org /wiki/Beta_decay (777 words)

	SIXTY YEARS OF DOUBLE BETA DECAY
		Nuclear double beta decay is one of the most promising tools for probing beyond-the-standard-model physics on beyond-accelerator energy scales.
		Today, the potential of double beta decay includes a broad range of topics that are equally relevant to particle physics and astrophysics, such as masses of heavy neutrinos, of sneutrinos, as SUSY models, compositeness, leptoquarks, left-right symmetric models, and tests of Lorentz symmetry and equivalence principle in the neutrino sector.
		Double beta decay has become indispensable nowadays for solving the problem of the neutrino mass spectrum and the structure of the neutrino mass matrix — together with present and future solar and atmospheric neutrino oscillation experiments.
	www.worldscibooks.com /physics/4032.html (278 words)

	Gamma ray - Wikipedia, the free encyclopedia
		Np; this alpha decay is accompanied by gamma emission.
		Because a beta decay is accompanied by the emission of a neutrino which also carries away energy, the beta spectrum does not have sharp lines, but instead it is a broad peak.
		Hence from beta decay alone it is not possible to probe the different energy levels found in the nucleus.
	en.wikipedia.org /wiki/Gamma_ray (1887 words)

	Rare Double Beta Decay Process is Observed
		A very rare form of nuclear disintegration called double beta decay was observed for the first time in 1986.
		Later, double beta decay was seen in other nuclei, including forms of calcium, germanium, and molybdenum.
		The methods developed for the experiment are being used to search for another rare decay mode, neutrino-less double beta decay, in which only the two electrons are emitted.
	www.er.doe.gov /Sub/Accomplishments/Decades_Discovery/46.html (309 words)

	Double beta decay
		The phenomenon of double beta decay is discussed rather fully both from the experimental and from the theoretical point of view, the relation between double beta decay and the possible kinds of inverse beta decay being also briefly treated.
		The theory of double beta decay, both in the no-neutrino and in the two-neutrino cases, is worked out, ab initio, on the basis of a nucleon-lepton interaction without conservation of parity.
		Comparison of the experimental limits on the double beta decay half-lives with the corresponding theoretical values indicates that two neutrinos are emitted together with two electrons in each double beta decay process - this conclusion is, however, not yet certain and must be confirmed by further experimental work.
	stacks.iop.org /0034-4885/22/121 (367 words)

	The NEMO experiment - Physics goals - The Double Beta Decay (Site not responding. Last check: 2007-10-02)
		Figure 10: Double beta decay; two neutrons are changed into protons inside the nucleus, emitting two electrons and two antineutrinos.
		The double beta decay process can be observed in a few isotopes for which all other decay channels are forbidden for energetic reasons (figure 11).
		Neutrinoless double beta decay is the only known process that enables to test experimentally the Majorana nature of neutrino together with its absolute mass scale.
	nemo.in2p3.fr /physics/dbd.php (604 words)

	Encyclopedia :: encyclopedia : Decay mode (Site not responding. Last check: 2007-10-02)
		For radioactive decay (the decay of nuclides) the decay modes are:
		decay (emission of a positron and a neutrino)
		Typically one decay mode predominates for a particular nuclide.
	www.hallencyclopedia.com /Decay_mode (152 words)

	Neutrinoless Double Beta Decay
		Dirac and pseudodirac neutrinos and neutrinoless double beta decay,
		EXO: the Enriched Xenon Observatory for Double Beta Decay,
		The neutrinoless double beta decay with majoron emission,
	www.nu.to.infn.it /Neutrinoless_Double_Beta_Decay (2676 words)

	[No title]
		This double-beta decay is the rarest form of nuclear decay so far observed, says John F. Wilkerson of the University of Washington in Seattle.
		If a neutrinoless double-beta decay occurs within the knee-high crystal tower that Fiorini and his colleagues are building, pairs of electrons should intermittently shoot out of a tellurium-130 nucleus into the rest of the crystal and deposit their energy there.
		In their experiments on neutrinoless double-beta decay, physicists may also find clues as to why the universe today is almost totally made up of matter, although it presumably started with an equal mix of both matter and antimatter, adds Wilkerson.
	www-project.slac.stanford.edu /exo/docs/Science_News_Article.txt (2423 words)

	Non Accelerator Particle Physics: HEIDELBERG-MOSCOW Experiment
		Double Beta decay corresponds to two simultaneous beta transitions in one nucleus.
		Double Beta decay with emission of two antineutrinos (2vBB) with half lives in the region of 10
		The evidence for this decay mode is 97% (2.2G) with the Bayesian method, and 99.8% c.l.
	www.mpi-hd.mpg.de /non_acc/dblbeta.html (1240 words)

	Report on meeting on neutrinoless double beta decay
		A general meeting was held at the RAL to discuss neutrinoless double beta decay, attended by about 40 people from the particle physics and nuclear physics communities.
		The most promising route seems to be neutrinoless double beta decay, which can potentially reach this sensitivity for a weighted average mass for the three neutrinos.
		Selenium seemed to be the optimum nucleus, although it was essential that neutrinoless double beta decay was observed in a number of nuclei.
	hepunx.rl.ac.uk /~edgecock/neutrinoless-summary-sep03.htm (1322 words)

	Double Beta Decay (and relevant Low-Level Counting) Working Group International Workshop (Site not responding. Last check: 2007-10-02)
		Neutrinoless double beta decay is a direct test of lepton number violation and, in most scenarios, probes the overall scale of neutrino mass.
		Recent measurements of solar and atmospheric neutrino oscillations, which depend on the differences in the squares of the masses, suggest that neutrinoless double beta decay might be observable in a new generation of experiments approximately a factor of 100 larger than those currently mounted.
		We have compiled a list of community members we believe are interested in double beta decay and low-level counting.
	www.int.washington.edu /bbdecay (424 words)

	symmetry - May 2005 - Searching for the Neutrino's Identity
		Standard double beta decay, in which two antineutrinos are released from the decaying nucleus, has already been observed.
		Hence the antineutrino emitted in one beta decay can be absorbed as a neutrino by the second one, resulting in neutrinoless double beta decay (see figure).
		If EXO observes neutrinoless double beta decay, physicists will have a strong case to argue that neutrinos are their own antiparticles.
	www.symmetrymagazine.org /cms?pid=1000113 (1810 words)

	CERN Courier - Team reports neutrinoless do - IOP Publishing - article
		Neutrinoless double beta decay violates lepton number conservation, a fundamental tenet of particle physics.
		Beta decay proceeds via the transformation of a neutron into a proton with the emission of a neutrino and an electron.
		In this case, two successive neutron decays could occur, with the neutrino emitted by the first being absorbed by the second.
	www.cerncourier.com /main/article/42/2/4 (260 words)

	[No title]
		Ordinary beta decay is the decay of a neutron (usually within a nucleus) into a proton, an electron, and an antineutrino.
		Thus, in the normal beta decay process, the initial and final lepton numbers are both zero.
		But if the neutrinos are of a particular form found in many extensions of the Standard Model, then they will be their own antiparticles, and there is then a mechanism for the double beta decay to proceed without emitting any neutrinos (or antineutrinos) at all.
	www.dushkin.com /text-data/weekly/cp02-25-02.mhtml (777 words)

	Simulation of the proposed SuperNEMO neutrinoless double beta decay experiment
		Neutrinoless double beta decay is a variant allowed in Grand Unified Theories where the right-handed neutrino plays a role, albeit a very small one.
		In neutrinoless double beta decay, the neutrons decay into protons emitting a W- in the process as in a single beta decay decay.
		The double beta decay emitters (constructed from metal films or powders) are then glued to mylar strips and hung within a segment between two concentric cylindrical tracking volumes.
	www.hep.ucl.ac.uk /~orme/index1.html (2637 words)

	Double beta decay (Site not responding. Last check: 2007-10-02)
		Then, a special decay is possible: the double beta decay without neutrino.
		The neutron inside the nucleus decays by emitting an anti-neutrino, which, if identical to the neutrino, can be re-absorbed by a proton of the nucleus, that becomes a neutron by emitting a positron (anti-electron).
		The experiments which are searching or have searched this type of beta decay have not found yet any signal.
	wwwlapp.in2p3.fr /neutrinos/adoublebeta.html (126 words)

	HomepagePublications
		Neutrinoless double beta decay and neutrino mass hierarchies
		Neutrinoless double beta decay, neutrinos mass spectrum and CP-violation in the lepton sector
		Analysis of the two-neutrino double beta decay and muon-capture reactions for the mass
	www.uni-tuebingen.de /ilias-dbd/src/HomepagePublications/publications.html (1402 words)

	Heidelberg-Moscow Double Beta Decay Experiment
		Data acquisition and analysis of the 76Ge double beta experiment in Gran Sasso 1990-2003
		Evidence in favor of the observation of neutrinoless double-beta decay of
		Critics of prominent members of the Double Beta Decay community to the claim in [2-10].
	www.nu.to.infn.it /exp/all/hei-mos (531 words)

	Double beta decay
		The study of nuclear double beta decay sheds light on physics beyond the standard model.
		It is nevertheless interesting in the sense that it probes the nuclear models with which the nuclear matrix elements for all the decay modes are calculated.
		decay in terms of neutrino masses and Majoron coupling.
	www.nupecc.org /report97/report97_neutrino/node32.html (280 words)

	PNNL Majorana Information Resources
		The objective of the Majorana experiment is to study neutrinoless double beta decay (0νββ) with an effective Majorana-neutrino mass sensitivity below 50 meV to characterize the Majorana nature of the neutrino, the neutrino mass spectrum, and the absolute mass scale.
		The Majorana Experiment is a complete next-generation double-beta decay experiment, using a large quantity of enriched materials, state-of-the-art detector fabrication, deep underground facilities, cutting-edge instrumentation and data analyses, and acquisition of complete systems-status data.
		APS Review: Neutrinoless double beta decay and direct searches for neutrino mass
	majorana.pnl.gov (786 words)

	Amazon.com: 60 Years of Double Beta Decay: Books: H. V. Klapdor-Kleingrothaus (Site not responding. Last check: 2007-10-02)
		Describes the history of double beta decay and its potential uses in particle physics.
		Uncovers previous in-depth research on double beta decay, discussing the level of sensitivity reached by experiments in this area.
		The history of double beta decay using the nucleus as a complicated laboratory for a wide range of particle physics starts more than 60 years ago.
	www.amazon.com /exec/obidos/tg/detail/-/9810237790?v=glance (543 words)

	Caltech Authors - Effective operators for double-beta decay
		We use a solvable model to examine double-beta decay, focusing on the neutrinoless mode.
		We then test both traditional and more recent prescriptions for constructing effective operators in small model spaces, concluding that the usual treatment of double-beta-decay operators in realistic calculations is unable to fully account for the neglected parts of the model space.
		The procedure eliminates the dependence of neutrinoless decay on some unfixed parameters and reduces the dependence on model-space size, though it does not eliminate the latter completely.
	resolver.caltech.edu /CaltechAUTHORS:ENGprc04 (260 words)

	got_art
		The decay rate is proportional to the squared mass.
		The sum energy spectrum is continuous, extending from 0 to Q. In the neutrinoless mode the total energy Q is carried away by the electrons, and the sum energy spectrum is a a peak centered at Q, with a width given by the instrumental resolution.
		Tracks having the topology corresponding to that expected for double beta decay events,namely two electrons coming from one single point, have been filtered out.
	www.unine.ch /phys/corpus/Gothard/got_art.html (631 words)

	Beyond 02: Presentation transparencies (Site not responding. Last check: 2007-10-02)
		DOUBLE BETA DECAY I and NEUTRINO MASS MATRIX
		Bergström: "On the Q-Values of the Tritium Beta-Decay and the 76Ge Double Beta-Decay Determined from Accurate Mass Measurements in a Penning Trap" Bergstrom.pdf (3 432 k)
		Sugiyama: "Constraints on Neutrino Mixing Parameters by Observation of Neutrinoless Double Beta Decay" SugiyamaH.pdf (3 376 k)
	cupp.oulu.fi /trans/transtue.html (203 words)

	IPPP workshop on neutrinoless double beta decay
		Within the Standard Model, neutrinoless double beta decay (0νββ) is forbidden; lepton number is violated.
		However, recent neutrino oscillation experiments strongly suggest that neutrinos are, in fact, massive particles and that the description of neutrinos within the Standard Model is not complete.
		The rate of decay via 0νββ will give a value for the absolute scale of neutrino mass.
	www.ippp.dur.ac.uk /~dph3sr/0NU2B (265 words)

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