616 research outputs found
Summary of Golden Measurements at a -Factory
The precision and discovery potential of a neutrino factory based on muon
storage rings is summarized. For three-family neutrino oscillations, we analyze
how to measure or severely constraint the angle , CP violation,
MSW effects and the sign of the atmospheric mass difference .
The appearance of ``wrong-sign muons'' at three reference baselines is
considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the
signal on the neutrino energy, and include as well realistic background
estimations and detection efficiencies. The optimal baseline turns out to be
(3000 km).Comment: 7 pages, Latex2e, 5 eps figures, use package espfi
Golden measurements at a neutrino factory
The precision and discovery potential of a neutrino factory based on muon
storage rings is studied. For three-family neutrino oscillations, we analyse
how to measure or severely constraint the angle , CP violation,
MSW effects and the sign of the atmospheric mass difference .
We present a simple analytical formula for the oscillation probabilities in
matter, with all neutrino mass differences non-vanishing, which clarifies the
subtleties involved in disentangling the unknown parameters. The appearance of
``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500
km, and 7332 km. We exploit the dependence of the signal on the neutrino
energy, and include as well realistic background estimations and detection
efficiencies. The optimal baseline turns out to be km).
Analyses combining the information from different baselines are also presented.Comment: 45 pages, Latex2e, 24 figures using epsfig.sty. An incorrect
statement and a few misprints have been corrected. Results and conclusions
are unchange
Physics Potential of Very Intense Conventional Neutrino Beams
The physics potential of high intensity conventional beams is explored. We
consider a low energy super beam which could be produced by a proposed new
accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil
scintillator detectors are studied as possible candidates for a neutrino
oscillation experiment which could improve our current knowledge of the
atmospheric parameters and measure or severely constrain the parameter
connecting the atmospheric and solar realms. It is also shown that a very large
water detector could eventually observe leptonic CP violation. The reach of
such an experiment to the neutrino mixing parameters would lie in-between the
next generation of neutrino experiments (MINOS, OPERA, etc) and a future
neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice,
March, 200
Sense and sensitivity of double beta decay experiments
The search for neutrinoless double beta decay is a very active field in which
the number of proposals for next-generation experiments has proliferated. In
this paper we attempt to address both the sense and the sensitivity of such
proposals. Sensitivity comes first, by means of proposing a simple and
unambiguous statistical recipe to derive the sensitivity to a putative Majorana
neutrino mass, m_bb. In order to make sense of how the different experimental
approaches compare, we apply this recipe to a selection of proposals, comparing
the resulting sensitivities. We also propose a "physics-motivated range" (PMR)
of the nuclear matrix elements as a unifying criterium between the different
nuclear models. The expected performance of the proposals is parametrized in
terms of only four numbers: energy resolution, background rate (per unit time,
isotope mass and energy), detection efficiency, and bb isotope mass. For each
proposal, both a reference and an optimistic scenario for the experimental
performance are studied. In the reference scenario we find that all the
proposals will be able to partially explore the degenerate spectrum, without
fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO)
will approach the 50 meV boundary. In the optimistic scenario, we find that
CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a
significant fraction of the inverse hierarchy, with NEXT covering it almost
fully. For the long term future, we argue that Xe-based experiments may provide
the best case for a 1-ton scale experiment, given the potentially very low
backgrounds achievable and the expected scalability to large isotope masses.Comment: 30 pages, 12 figures, 6 table
disappearance at the SPL, T2K-I and the Neutrino Factory
We study the disappearance channel at T2K-phase I and the SPL and
analyse the achievable reduction of present uncertainties in and
. We analyse the impact of discrete ambiguities in
sign() and sign(). We show how the
disappearance channel at the Neutrino Factory is complementary to the
``golden'' and ``silver'' appearance channels and can be used to reduce the
eightfold-ambiguity problem in ().Comment: 2 pages, 3 epsfig; NUFACT'05, 21-26 June 2005, Frascat
Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions
To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress
Searches for neutrinoless double beta decay
Neutrinoless double beta decay is a lepton number violating process whose
observation would also establish that neutrinos are their own anti-particles.
There are many experimental efforts with a variety of techniques. Some (EXO,
Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has
reported the first measurement of the half life for the double beta decay with
two neutrinos of Xe. The sensitivities of the different proposals are
reviewed.Comment: 8 pages, prepared for TAUP 201
Searches for neutrinoless double beta decay
Neutrinoless double beta decay is a lepton number violating process whose
observation would also establish that neutrinos are their own anti-particles.
There are many experimental efforts with a variety of techniques. Some (EXO,
Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has
reported the first measurement of the half life for the double beta decay with
two neutrinos of Xe. The sensitivities of the different proposals are
reviewed.Comment: 8 pages, prepared for TAUP 201
- …