Leptogenesis in GeV-scale seesaw models Hernández, P.; Kekic, M.; López-Pavón, J. ...
The journal of high energy physics,
10/2015, Letnik:
2015, Številka:
10
Journal Article
Recenzirano
Odprti dostop
A
bstract
We revisit the production of leptonic asymmetries in minimal extensions of the Standard Model that can explain neutrino masses, involving extra singlets with Majorana masses in the GeV ...scale. We study the quantum kinetic equations both analytically, via a perturbative expansion up to third order in the mixing angles, and numerically. The analytical solution allows us to identify the relevant CP invariants, and simplifies the exploration of the parameter space. We find that sizeable lepton asymmetries are compatible with non-degenerate neutrino masses and measurable active-sterile mixings.
Testable baryogenesis in seesaw models Hernández, P.; Kekic, M.; López-Pavón, J. ...
The journal of high energy physics,
08/2016, Letnik:
2016, Številka:
8
Journal Article
Recenzirano
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A
bstract
We revisit the production of baryon asymmetries in the minimal type I seesaw model with heavy Majorana singlets in the GeV range. In particular we include “washout” effects from scattering ...processes with gauge bosons, Higgs decays and inverse decays, besides the dominant top scatterings. We show that in the minimal model with two singlets, and for an inverted light neutrino ordering, future measurements from SHiP and neutrinoless double beta decay could in principle provide sufficient information to predict the matter-antimatter asymmetry in the universe. We also show that SHiP measurements could provide very valuable information on the PMNS CP phases.
The sensitivity of direct searches for heavy neutral leptons (HNLs) in accelerator-based experiments depends strongly on the particles properties. Commonly used benchmark scenarios are important to ...ensure comparability and consistency between experimental searches, re-interpretations, and sensitivity studies for different facilities. In models where the HNLs are primarily produced and decay through the weak interaction, benchmarks are in particular defined by fixing the relative strengths of their mixing with SM neutrinos of different flavours, and the interpretation of experimental data is known to strongly depend on those ratios. The commonly used benchmarks in which a single HNL flavour exclusively interacts with one Standard Model generation do not reflect what is found in realistic neutrino mass models. We identify two additional benchmarks for accelerator-based direct HNL searches, which we primarily select based on the requirement to provide a better approximation for the phenomenology of realistic neutrino mass models in view of present and future neutrino oscillation data.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
We revisit the generation of a matter-antimatter asymmetry in the minimal extension of the Standard Model with two singlet heavy neutral leptons (HNL) that can explain neutrino masses. We ...derive an accurate analytical approximation to the solution of the complete linearized set of kinetic equations, which exposes the non-trivial parameter dependencies in the form of parameterization-independent CP invariants. The identification of various washout regimes relevant in different regions of parameter space sheds light on the relevance of the mass corrections in the interaction rates and clarifies the correlations of baryogenesis with other observables. In particular, by requiring that the measured baryon asymmetry is reproduced, we derive robust upper or lower bounds on the HNL mixings depending on their masses, and constraints on their flavour structure, as well as on the CP-violating phases of the PMNS mixing matrix, and the amplitude of neutrinoless double-beta decay. We also find certain correlations between low and high scale CP phases. Especially emphasizing the testable part of the parameter space we demonstrate that our findings are in very good agreement with numerical results. The methods developed in this work can help in exploring more complex scenarios.
A low-energy non-unitary leptonic mixing matrix is a generic effect of a large class of theories accounting for neutrino masses. It is shown how the extra CP-odd phases of a general non-unitary ...matrix allow for sizeable CP-asymmetries in channels other than those dominant in the standard unitary case. The νμ→ντ channel turns out to be an excellent tool to further constrain moduli and phases. Furthermore, we clarify the relationship between our approach and the so-called “non-standard neutrino interactions” schemes: the sensitivities explored here apply as well to such constructions.
Magnetic nanoparticles (MNPs) are a new kind of nanometer-sized superparamagnetic material with potential applications as magnetic carriers for various biomedical uses, wastewater remediation, ...preconcentration of various anions and cations, etc. The excellent properties of MNPs are strongly influenced by the size of the nanoparticles. Another important factor is the amount of iron present. In this work, a simple and inexpensive approach was developed for the direct determination of the Fe concentration and particle size of solid MNPs by solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). A new strategy of evaluating the area and upslope of the obtained absorbance signals for a line of Fe (352.614 nm) with low sensitivity was developed for both determinations. For this purpose, five furnace program parameters, atomization heating rate, atomization temperature, pyrolysis heating rate, pyrolysis temperature and pyrolysis hold time, were optimized with the employment of two multiple response surface designs. With the optimized furnace parameters, satisfactory calibration curves were obtained with liquid iron standards (for Fe determination) ( R ≥ 0.995) and with MNP samples with a certified size of particle (for size particle determination) ( R ≥ 0.990). The determinations of the MNPs’ size and their iron percentage were validated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. This method can be employed in the optimization of the synthesis of MNPs by the coprecipitation method.
A
bstract
We consider the generation of a baryon asymmetry in an extension of the Standard Model with two singlet Majorana fermions that are degenerate above the electroweak phase transition. The ...model can explain neutrino masses as well as the observed matter-antimatter asymmetry, for masses of the heavy singlets below the electroweak scale. The only physical CP violating phases in the model are those in the PMNS mixing matrix, i.e. the Dirac phase and a Majorana phase that enter light neutrino observables. We present an accurate analytic approximation for the baryon asymmetry in terms of CP flavour invariants, and derive the correlations with neutrino observables. We demonstrate that the measurement of CP violation in neutrino oscillations as well as the mixings of the heavy neutral leptons with the electron, muon and tau flavours suffice to pin down the matter-antimatter asymmetry from laboratory measurements.
Highlights • Inflammatory response genes were seen in Glässer’s disease by microarray and qPCR. • Lower expression of them was seen in pigs vaccinated with an H. parasuis mutant TbpB. • Cell damage ...genes were seen in Glässer’s disease by microarray and qPCR. • Lower expression of them was seen in pigs vaccinated with an H. parasuis mutant TbpB. • Gene and protein expression was similar in mutant TbpB vaccinated and healthy pigs
A chelating sorbent which employs magnetic nanoparticles (MNPs) functionalized with 1,5-bis(di-2-pyridil)methylene thiocarbohydrazide (DPTH-MNPs) was used to develop a simple method for the analysis ...of trace amounts of metal ions (As, Sb and Hg) present in environmental samples combining on-line magnetic solid phase extraction (MSPE) with atomic spectrometry. The application of hydride generation with high resolution continuum source electrothermal atomic absorption spectrometry (HR CS ETAAS) improves the sensitivity of As, Sb and Hg determination.
This method has proven to have a high sensitivity with detection limits of 0.25 μg L−1, 0.003 μg L−1 and 0.22 μg L−1 for As, Sb and Hg, respectively. Besides, the proposed method was applied in the sequential determination of the 3 elements mentioned above with a sample throughput of about 16.7 h−1, thereby, reducing the time of analysis and the volume of reagents and sample required. This method was applied to determine the target elements in a TMDA 54.5 and TM 24.3 certified reference materials, and seawater collected from Malaga Bay. The results showed good agreement with the certified values.
•The on-line DPTH-MNPs/HR CS ETAAS system is promising for routine analysis.•It is a low cost and environmentally friendly tool for elemental studies.•It has proved useful for determination of Sb, As and Hg in environmental waters (seawater).
A
bstract
We study the constraints imposed by neutrino oscillation experiments on the minimal extension of the Standard Model that can explain neutrino masses, which requires the addition of just two ...singlet Weyl fermions. The most general renormalizable couplings of this model imply generically four massive neutrino mass eigenstates while one remains massless: it is therefore a minimal 3 + 2 model. The possibility to account for the confirmed solar, atmospheric and long-baseline oscillations, together with the LSND/MiniBooNE and reactor anomalies is addressed. We find that the minimal model can fit oscillation data including the anomalies better than the standard 3
ν
model and similarly to the 3 + 2 phenomenological models, even though the number of free parameters is much smaller than in the latter. Accounting for the anomalies in the minimal model favours a normal hierarchy of the light states and requires a large reactor angle, in agreement with recent measurements. Our analysis of the model employs a new parametrization of seesaw models that extends the Casas-Ibarra one to regimes where higher order corrections in the light-heavy mixings are significant.
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