Damping signatures in future neutrino oscillation experiments

We discuss the phenomenology of damping signatures in the neutrino oscillation probabilities, where either the oscillating terms or the probabilities can be damped. This approach is a possibility for tests of non-oscillation effects in future neutrino oscillation experiments, where we mainly focus on reactor and long-baseline experiments. We extensively motivate different damping signatures due to small corrections by neutrino decoherence, neutrino decay, oscillations into sterile neutrinos, or other mechanisms, and classify these signatures according to their energy (spectral) dependencies. We demonstrate, at the example of short baseline reactor experiments, that damping can severely alter the interpretation of results, e.g., it could fake a value of $\sin(2\theta_{13})$ smaller than the one provided by Nature. In addition, we demonstrate how a neutrino factory could constrain different damping models with emphasis on how these different models could be distinguished, i.e., how easily the actual non-oscillation effects could be identified. We find that the damping models cluster in different categories, which can be much better distinguished from each other than models within the same cluster.Comment: 33 pages, 5 figures, LaTeX. Final version published in JHE

Signature of sterile species in atmospheric neutrino data at neutrino telescopes

The MiniBooNE results have still not been able to comprehensively rule out the oscillation interpretation of the LSND experiment. So far the so-called short baseline experiments with energy in the MeV range and baseline of few meters have been probing the existence of sterile neutrinos. We show how signatures of these extra sterile states could be obtained in TeV energy range atmospheric neutrinos travelling distances of thousands of kilometers. Atmospheric neutrinos in the TeV range would be detected by the upcoming neutrino telescopes. Of course vacuum oscillations of these neutrinos would be very small. However, we show that resonant matter effects inside the Earth could enhance these very tiny oscillations into near-maximal transitions, which should be hard to miss. We show that imprint of sterile neutrinos could be unambiguously obtained in this high energy atmospheric neutrino event sample. Not only would neutrino telescopes tell the presence of sterile neutrinos, it should also be possible for them to distinguish between the different possible mass and mixing scenarios with additional sterile states.Comment: 26 pages, 11 figures, Version to appear in JHE

Biosensors based on conductometric detection

The present paper is a self-review on the development of about 20 conductometric biosensors based on planar electrodes and containing different biological material (enzymes, cells, antibodies), bio-mimics or synthetic membranes, including Imprinting polymers, as a sensitive element. Highly specific, sensitive, simple, fast and cheap determination of different analytes makes them promising for needs of medicine, biotechnology, environmental control, agriculture and food industry. Non-specific interference of back-ground ions may be overcome by the differential mode of measurement, the usage of rather concentrated sample buffer and additional negatively or positively charged membranes, which decrease buffer capacity influence and extend a dynamic range of sensors response. For development of easy-to-use small conductometric immunosensors several approaches seem to be promising: i) the usage of polyaniline as electroconductive label for antibodies detection in competitive electroimmunoassay; ii) the elaboration of multilayer structures with phtalocyanine films; iii) the usage of acrylic copolymeric membranes. The advantages and disadvantages of conductometric biosensors created are discussed. For future commercialisation our effort are aimed to unite a thin-film technology with membranes deposition and to find the ways of membrane stabilisation, including bio-mimics creation, utilisation of bioaffinity polymeric membranes, imprinting polymers etc.Огляд присвячено аналізу власних робіт з розробки близько 20 кондуктометричних біосенсорів на основі планарних електродів та різноманітного біологічного матеріалу (ферменти, клітини, антитіла), синтетичних мембран як чутливих елементів. Висока селективність, чутливість, низька ціна, простота та експресність визначення різноманітних речовин роблять біосенсори необхідними для потреб медицини, біотехнологїі, екологи, сільського господарства та харчової промисловості. При аналізі реальних зразків неспецифічний вплив фонових електролітів можна суттєво зменшити завдяки використанню диференційного режиму вимірювань, більш концентрованих буферних розчинів, а також додаткових негативно чи позитивно заряджених мембран, які запобігають впливові буферної ємності та іонної сили розчинів і розширюють динамічний діапазон роботи сенсорів. Для створення мініатюрних імуносенсорів було запропоновано такі підходи: а) використання поліаніліну як електропровідної мітки при виз наче пні антитіл у конкурентному імуноаналізі: б) створення багатошарових структур з плівками фталоціаніну; в) використання акрилових сополімерних мембран. Обговорено переваги та недоліки розроблених кондуктометричних біосенсорів. Подальша комерціалізація таких приладів пов'язана з пошуком шляхів стабілізації чутливих мембран та суміщення тонкоплівкових технологій з нанесенням мембран у єдиному технологічному циклі.Обзор посвящен анализу собственных работ по разработке около 20 кондуктометрических биосенсоров на. основе планарных электродов и различного биологического материала, (ферменты, клетки, антитела) и синтетических мембран о качестве чувствительных элементов. Высокая селективность, чувствительность, дешевизна, простота и быстрота определения различных веществ делают биосенсоры необходимыми в медицине, биотехнологии, экологии, сельском хозяйстве и пищевой промышленности. При анализе реальных образцов неспецифическое влияние фоновых электролитов можно устранить благодаря использованию дифференциального режима измерений, более концентрированных буферных растворов, а также дополнительных отрицательно или положительно заряженных мембран, уменьшающих влияние буферной емкости и ионной силы растворов и расширяющих динамический диапазон работы сенсоров. Для создания миниатюрных иммуносенсоров предложены следующие подходы: а) использование полианилина как электропроводящей метки при определении антител в конкурентном иммуноанализе; б) создание многослойных структур с пленками на основе фталоцианина; в) использование акриловых со полимерных мембран. Обсуждены преимущества и недостатки разработанных кондуктометрических биосенсоров. Дальнейшая коммерциализация, таких приборов связана с поиском путей стабилизации чувствительных мембран и совмещения, тонкопленочной технологии с нанесением мембран в едином технологическом цикле

From parameter space constraints to the precision determination of the leptonic Dirac CP phase

We discuss the precision determination of the leptonic Dirac CP phase $\delta_{CP}$ in neutrino oscillation experiments, where we apply the concept of ``CP coverage''. We demonstrate that this approach carries more information than a conventional CP violation measurement, since it also describes the exclusion of parameter regions. This will be very useful for next-generation long baseline experiments where for sizable $\sin^2 2 \theta_{13}$ first constraints on $\delta_{CP}$ can be obtained. As the most sophisticated experimental setup, we analyze neutrino factories, where we illustrate the major difficulties in their analysis. In addition, we compare their potential to the one of superbeam upgrades and next-generation experiments, which also includes a discussion of synergy effects. We find a strong dependence on the yet unknown true values of $\sin^2 2 \theta_{13}$ and $\delta_{CP}$, as well as a strong, non-Gaussian dependence on the confidence level. A systematic understanding of the complicated parameter dependence will be given. In addition, it is shown that comparisons of experiments and synergy discussions do in general not allow for an unbiased judgment if they are only performed at selected points in parameter space. Therefore, we present our results in dependence of the yet unknown true values of $\sin^2 2 \theta_{13}$ and $\delta_{CP}$. Finally we show that for $\delta_{CP}$ precision measurements there exist simple strategies including superbeams, reactor experiments, superbeam upgrades, and neutrino factories, where the crucial discriminator is $\sin^2 2 \theta_{13} \sim 10^{-2}$.Comment: 32 pages, 9 figure

Optimized Two-Baseline Beta-Beam Experiment

We propose a realistic Beta-Beam experiment with four source ions and two baselines for the best possible sensitivity to theta_{13}, CP violation and mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are detected in a 500 kton water Cerenkov detector at a distance L=650 km (first oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from the source. Since the decay ring requires a tilt angle of 34.5 degrees to send the beam to the magic baseline, the far end of the ring has a maximum depth of d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction of ions that decay along the straight sections of the racetrack geometry decay ring (called livetime) is 0.3. We alleviate this problem by proposing to trade reduction of the livetime of the decay ring with the increase in the boost factor of the ions, such that the number of events at the detector remains almost the same. This allows to substantially reduce the maximum depth of the decay ring at the far end, without significantly compromising the sensitivity of the experiment to the oscillation parameters. We take 8B and 8Li with gamma=390 and 656 respectively, as these are the largest possible boost factors possible with the envisaged upgrades of the SPS at CERN. This allows us to reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field. Increase of magnetic field to 15 T would further reduce d to 738 m only. We study the sensitivity reach of this two baseline two storage ring Beta-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.Comment: 17 pages, 3 eps figures. Minor changes, matches version accepted in JHE

Pioneering space based detector for study of cosmic rays beyond GZK Limit

Space-based detectors for study of extreme energy cosmic rays (EECR) are being prepared as promising new direction of EECR study. Pioneering space device – tracking ultraviolet set up (TUS) is at the last stage of its construction and testing. TUS detector description is presented