259 research outputs found
A study on a minimally broken residual TBM-Klein symmetry with its implications on flavoured leptogenesis and ultra high energy neutrino flux ratios.
No full textWe present a systematic study on minimally perturbed neutrino mass matrices which at the leading order give rise to Tri-BiMaximal (TBM) mixing due to a residual Bbb Z2× Bbb Z2μτ Klein symmetry in the neutrino mass term of the low energy effective seesaw Lagrangian. Considering only the breaking of Bbb Z2μτ with two relevant breaking parameters (epsilon4,6'), after a comprehensive numerical analysis, we show that the phenomenologically viable case in this scenario is a special case of TM1 mixing. For this class of models, from the phenomenological perspective, one always needs large breaking (more than 45%) in one of the breaking parameters. However, to be consistent the maximal mixing of θ23, while more than 35% breaking is needed in the other, a range 49.4o−53o and 38o−40o could be probed allowing breaking up to 25% in the same parameter. Thus though this model cannot distinguish the octant of θ23, non-maximal mixing is preferred from the viewpoint of small breaking. The full Bbb Z2× Bbb Z2μτ symmetry leads to a degeneracy in the eigenvalues of right handed (RH) neutrino mass matrices (MR). Nevertheless, breaking of Bbb Z2μτ which is also necessary to generate nonzero θ13 in this model, lifts that degeneracy. Thus unlike the standard N1-leptogenesis scenario where only the decays and other interactions due to the lightest RH neutrino N1 are relevant, here all the RH neutrinos contribute to the process of baryogenesis via leptogenesis due to the small mass splitting controlled by the Bbb Z2μτ breaking parameters. Including flavour coupling effects (In general, which have been partially included in all the leptogenesis studies in perturbed TBM framework), we solve flavour dependent coupled Boltzmann equations for heavy neutrino as well as the light leptonic number densities to compute the final baryon asymmetry YB. Thus our analysis and results pertaining to a successful leptogenesis are more accurate than any other studies in existing literature that deal with perturbed TBM scenario. Finally, in the context of recent discovery of the ultra high energy (UHE) neutrino events at IceCube, assuming UHE neutrinos originate from purely astrophysical sources, we obtain prediction on the neutrino flux ratios at neutrino telescopes
Representing seesaw neutrino models and their motion in lepton flavour space
No full textWe discuss how seesaw neutrino models can be graphically represented in lepton flavour space. We examine various popular models and show how this representation helps understanding their properties and connection with experimental data showing in particular how certain texture zero models are ruled out. We also introduce a new matrix, the bridging matrix, that brings from the light to the heavy neutrino mass flavour basis, showing how this is related to the orthogonal matrix and how different quantities are easily expressed through it. We then show how one can randomly generate orthogonal and leptonic mixing matrices uniformly covering all flavour space in an unbiased way (Haar-distributed matrices). Using the isomorphism between the group of complex rotations and the Lorentz group, we also introduce the concept of Lorentz boost in flavour space for a seesaw model and how this has an insightful physical interpretation. Finally, as a significant application, we consider N2-leptogenesis. Using current experimental values of low energy neutrino parameters, we show that the probability that at least one flavoured decay parameter of the lightest right-handed neutrino is smaller than unity is about 49% (to be compared with the tiny probability that the total decay parameter is smaller than unity, P (KI< 1) ∼ 0.1%, confirming the crucial role played by flavour effects). On the other hand when m1 ≳ 0.1 eV this probability reduces to less than 5%, showing how also N2-leptogenesis disfavours degenerate light neutrinos
Non-thermal production of lepton asymmetry and dark matter in minimal seesaw with right handed neutrino induced Higgs potential
No full textWithin Type-I seesaw mechanism, Higgs mass can be dynamically generated via quantum effects of the right handed neutrinos assuming the potential is nearly conformal at the Ultra-Violet. The scenario, named as the "Neutrino Option" allows RH neutrino mass scale upto GeV to be consistent with light neutrino masses, mixing and Higgs mass. Therefore, it is not consistent with standard hierarchical thermal leptogenesis. Parameter space for thermal resonant leptogenesis is highly constrained in this model. We point out that non-thermal pair production of RH neutrinos from inflaton decay corresponds in general to a mild degree of resonance in the CP asymmetry parameter and allows RH mass scale to be smaller more than by an order of magnitude than the thermal strong resonance case. Within the similar parameter space of thermal leptogenesis, RH neutrinos can also be produced from inflaton decay along with a Dark Matter having mass 320 MeV. The main constraint in the latter scenario comes from the Ly constraints on Dark Matter free streaming. We show in addition, that the Neutrino Option introduces a 'phantom window' for the RH mass scale, in which contrary to the usual scenarios, CP asymmetry parameter for leptogenesis decreases with the increase of the RH mass scale and minimally fine-tuned seesaw models naturally exhibit this `phantom window'
Mães perturbadoras, filhos monstruosos: uma leitura de Distância de resgate, de Samanta Schweblin
No full textDistância de resgate (2016) é a primeira e única novela de Samanta Schweblin, escritora argentina tradicionalmente contista. A narrativa se dá através de um diálogo alucinante entre a narradora e seu interlocutor, e tem como tema central a relação ao mesmo tempo delicada e perturbadora entre duas mães e seus respectivos filhos. O presente trabalho é guiado pelo interesse em analisar tais relações, com foco nas tradicionais noções de instinto materno e inocência infantil. Com o intuito de auxiliar no entendimento das temáticas destacadas, propõe-se o estudo de contos selecionados da autora. Tenciona-se, finalmente, discorrer acerca das manifestações do fantástico nos textos citados, considerando-se que a distorção sutil da realidade é um dos traços marcantes da produção de Schweblin.Fever dream (2016) is the first and only novel ever written by Samanta Schweblin, an Argentinian short story writer. The narrative develops itself through a conversation between the narrator and her interlocutor, and focuses mainly on the delicate yet disturbing relationship between two mothers and their children. The present paper is guided by the interest of analyzing these relations, focusing on the traditional concepts of maternal instinct and child innocence. With the intention of helping in the understanding of these themes, a study of selected short stories by the author will be made. Finally, the manifestation of the fantastic genre in the mentioned texts will be studied, considering that the distortion of reality is one of the distinct traits of Schweblins production
Informetrics on M. N. Srinivas
No full textM. N. Srinivas, the well known sociologist is widely recognised as architect of modern Indian sociology and social anthropology. His publications have been analysed by year, domain, authorship pattern, channels of communication used. Keywords, etc. The results indicate that the papers published by him are of a nature that qualify him to be a 'role model' for the younger generations to emulate.
By the end of 1995, Srinivas had to his credit 144 papers which, included 33 broad papers in sociology and anthropology; 18 papers in social change; 28 papers in village studies; 12 papers on religion; 17 papers on caste and 36 papers of general popular interest. The periods 1958-61 and 1974-77, when Srinivas was 38-41 and 58-61 years old. were his most productive periods with highest publication activity
Density matrix calculation of the dark matter abundance in the Higgs induced right-handed neutrino mixing model
No full textWe present new results on the calculation of the dark matter relic abundance within the Higgs induced right-handed neutrino mixing model, solving the associated density matrix equation. For a benchmark value of the dark matter mass MDM = 220 TeV, we show the evolution of the abundance and how this depends on reheat temperature, dark matter lifetime and source right-handed neutrino mass MS, with the assumption MS < MDM. We compare the results with those obtained within the Landau-Zener approximation, showing that the latter largely overestimates the final abundance giving some analytical insight. However, we also notice that since in the density matrix formalism the production is non-resonant, this allows source right-handed neutrino masses below the W boson mass, making dark matter more stable at large mass values. This opens an allowed region for initial vanishing source right-handed neutrino abundance. For example, for MS ≳ 1 GeV, we find MDM≳ 20 PeV. Otherwise, for MS > MW∼ 100 GeV, one has to assume a thermalisation of the source right-handed neutrinos prior to the freeze-in of the dark matter abundance. This results into a large allowed range for MDM, depending on MS. For example, imposing MS ≳ 300 GeV, allowing also successful leptogenesis, we find 00.5 ≲ MDM/TeV ≲ 50. We also discuss in detail leptogenesis with two quasi-degenerate right-handed neutrinos, showing a case when observed dark matter abundance and matter-antimatter asymmetry are simultaneously reproduced. Finally, we comment on how an initial thermal source right-handed neutrino abundance can be justified and on how our results suggest that also the interesting case where MDM < MS, embeddable in usual high scale two right-handed neutrino seesaw models, might be viable
The body and ritual healing in Samanta Schweblin's "Fever Dream"
No full textLiterature is able to give a new significance to clinical facts by revealing the potentiality that its signifiers acquire through time and the evolution of social groups. In this study I propose an analysis of the metaphoric function of the concept of the body (in its meaning of the social body) and ritual healing in Fever Dream by Samanta Schweblin. The aim is to study how these elements contribute to contextualizing the environmental denouncement of the use of toxic chemicals described by the author
O feminino e o insólito nos contos de Samanta Schweblin
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-graduação em Literatura, 2020.Esta pesquisa se propõe analisar alguns contos da escritora Samanta Schweblin, observando a representação do feminino em sua obra e o discurso contemporâneo sobre a maternidade e as relações familiares. A autora explora tais temáticas sob o viés do fantástico literário, conformando um cotidiano insólito e inquietante para contar suas histórias, portanto pretende-se também averiguar quais elementos e estratégias narrativas são empregados pela autora para deslindar a outra face da realidade que constrói em seus contos.Abstract: This research proposes to analyze Samanta Schweblin's short stories, observing the feminine representation and the contemporary discourse on motherhood and family relationships. The author explores these subjects from the Fantastic Literature perspective, forming an unusual and disturbing daily life to tell her stories. So, this research also intends to find out which elements and narrative strategies are used by the writer to unravel the other face of the reality she builds in her short stories
El cuento neofantástico en la tradición rioplatense : Siete casas vacías de Samanta Schweblin
No full textEl presente trabajo analiza el cuento neofantástico en la tradición rioplatense a través de la obra Siete casas vacías de Samanta Schweblin, comparando así mismo dos relatos con uno de Julio Cortázar, Casa tomada. A través de conceptos como lo siniestro, lo weird y el espejo se estudian tres cuentos con el fin de demostrar cómo la autora actualiza y transforma el legado del cuento fantástico latinoamericano.El present treball analitza el conte neofantàstic en la tradició rioplatense a traves de l'obra Set cases buides de Samanta Schweblin, comparant així dos relats amb Julio Cortázar i el seu conte Casa presa. A traves de conceptes com allò sinistre, weird i el mirall s'estudien tres contes amb la finalitat de demostrar com l'autora actualitza i transforma el llegat del conte fantàstic llatinoamericà.The current assessment analyses the neo fantastic tale in the rioplatense tradition, through the work from Samanta Schwebnlin, Seven empty houses. This way we are comparing two stories with the one from Julio Cortazar, Casa Tomada. Through concepts such as the uncanny, the weird and the mirror we study three tale with the purpose of showing how the author upgrades and transforms the legacy from the latin American fantasy stor
Linear stability of a liquid flow through a poroelastic channel
No full textA liquid flow through a channel is studied based on the Orr-Sommerfeld eigenvalue problem, where the lower wall of the channel is occupied by the saturated poroelastic medium. The linear stability analysis is investigated in detail for arbitrary value of the wavenumber. The eigenvalues are computed numerically by using the Chebyshev spectral collocation method. The effect of physical parameters, for instance, permeability, elasticity as well as their combined effect on the unstable modes are examined
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