scholarly journals Squeezing the Parameter Space for Lorentz Violation in the Neutrino Sector with Additional Decay Channels

Particles ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 630-641
Author(s):  
Ulrich D. Jentschura

The hypothesis of Lorentz violation in the neutrino sector has intrigued scientists for the last two to three decades. A number of theoretical arguments support the emergence of such violations, first and foremost for neutrinos, which constitute the “most elusive” and “least interacting” particles known to mankind. It is of obvious interest to place stringent bounds on the Lorentz-violating parameters in the neutrino sector. In the past, the most stringent bounds have been placed by calculating the probability of neutrino decay into a lepton pair, a process made kinematically feasible by Lorentz violation in the neutrino sector, above a certain threshold. However, even more stringent bounds can be placed on the Lorentz-violating parameters if one takes into account, additionally, the possibility of neutrino splitting, i.e., of neutrino decay into a neutrino of lower energy, accompanied by “neutrino-pair Čerenkov radiation.” This process has a negligible threshold and can be used to improve the bounds on Lorentz-violating parameters in the neutrino sector. Finally, we take the opportunity to discuss the relation of Lorentz and gauge symmetry breaking, with a special emphasis on the theoretical models employed in our calculations.

2019 ◽  
Vol 28 (09) ◽  
pp. 1950072 ◽  
Author(s):  
U. D. Jentschura ◽  
I. Nándori ◽  
G. Somogyi

Conceivable Lorentz-violating effects in the neutrino sector remain a research area of great general interest, as they touch upon the very foundations on which the Standard Model and our general understanding of fundamental interactions are laid. Here, we investigate the relation of Lorentz violation in the neutrino sector in light of the fact that neutrinos and the corresponding left-handed charged leptons form [Formula: see text] doublets under the electroweak gauge group. Lorentz-violating effects thus cannot be fully separated from questions related to gauge invariance. The model dependence of the effective interaction Lagrangians used in various recent investigations is explored with a special emphasis on neutrino splitting, otherwise known as the neutrino-pair Cerenkov radiation and vacuum-pair emission (electron–positron-pair Cerenkov radiation). We highlight two scenarios in which Lorentz-violating effects do not necessarily also break electroweak gauge invariance. The first of these involves a restricted set of gauge transformations, a subgroup of [Formula: see text], while in the second where differential Lorentz violation is exclusively introduced by the mixing of the neutrino flavor and mass eigenstates. Our study culminates in a model which fully preserves [Formula: see text] gauge invariance, involves flavor-dependent Lorentz-breaking parameters, and still allows for Cerenkov-type decays to proceed.


Author(s):  
Lauren Stewart ◽  
Katharina von Kriegstein ◽  
Simone Dalla Bella ◽  
Jason D. Warren ◽  
Timothy D. Griffiths

This article presents an overview of case studies of acquired disorders of musical listening. Like any cognitive faculty, music is multifaceted, and the identification of the neural basis of any complex faculty must proceed, hand in hand, with an elucidation of its cognitive architecture. The past decade has seen an evolution in the theoretical models of musical processing, allowing the development of theoretically motivated instruments for the systematic evaluation of musical disorders. Such developments have allowed reports of musical disorders to evolve from historical anecdotes to systematic, verifiable accounts that can play a critical role in contributing to our understanding of the cognitive neuroscience of music.


Sociologija ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 285-306
Author(s):  
Milan Cakic

The main topic of this article are the motives that led to the adoption of lustration laws in the Czech Republic, Poland, and Serbia, and their social functions. In the opening section, lustration is placed in the wider framework of dealing with the past and two possible approaches to the phenomenon are discussed: to take it as part of the broader process of decommunization, or a measure of transitional justice. In the next section an attempt at defining the concept of lustration is made, with a view to eliminating some ambiguities surrounding it. Subsequently, two partially complementary theoretical models explaining the occurrence, form and severity of dealing with the past and lustration are presented. After that comes the description of the socio-political context at the time of the adoption of lustration laws in the three countries and identification of political and ideological forces that have supported or challenged it. Finally, the article attempts to answer the question whether lustration is a legitimate measure of settling historical justice, overcoming the legacies of socialism, a way to strengthen liberal democracy, or merely a tool in political struggles for power.


2021 ◽  
Author(s):  
◽  
Elspeth Hocking

<p>Public history and academic history have been viewed both as opposites, two practices related only by their concern with sharing the past, as well as conceptualised as similar fields with close connections to each other. Museum history exhibitions are an obvious example of public history in action. However, is the history that exhibitions present all that different from what is produced in the academy, or is this history academia in another form? Initially this dissertation aimed to explore the relationships between academic and public histories as discipline and practice, assuming a relationship rather than divide between the two fields as suggested in some of the literature. However, the eventual results of the research were different than expected, and suggested that in fact public histories manifest very differently to academic histories within a museum context. Using an adapted ethnographic research methodology, this dissertation traces the development of a single history exhibition, "Te Ahi Kā Roa, Te Ahi Kātoro Taranaki War 1860–2010: Our Legacy – Our Challenge", from its concept development to opening day and onwards to public programmes. This exhibition opened at Puke Ariki in New Plymouth in March 2010, and was a provocative display not only of the history of the wars themselves, but of the legacy of warfare in the Taranaki community. Other methods include partially structured interviews which were conducted with ten people involved in creating this exhibition, who outlined their roles in its production and provided their views on its development, and also a brief analysis of the broader social and historical context in which the exhibition was staged. Through tracing the creation of this history, the findings suggested that the history produced at Puke Ariki is a history in its own right, with noticeable differences from academic histories. The strongest correlation between public and academic history in this instance was the shared aspiration to be rigorous in conducting research and, as far as possible, to create an accurate portrayal of the past. Otherwise the history created by Puke Ariki through the exhibition proved to be different in that it was deliberately designed to be very accessible, and it utilised a number of presentation modes, including objects, text, audiovisual and sound. It was interactive, and had a clear aim of enabling the audience to participate in a discussion about the history being presented. Finally, it was a highly politicised history, in that decision making had to be negotiated with source communities in a collaborative fashion, and issues of censorship worked through with the council, a major funding source. The dissertation concludes that producing history in a museum context is a dynamic and flexible process, and one that can be successful despite not necessarily following theoretical models of exhibition development.</p>


Author(s):  
Gennaro Pellone

<span>The place of the computer in the classroom especially within TAFE Colleges has increased dramatically over the past decade. This paper attempts to describe the role of computers in TAFE education providing some understanding of the principal theoretical models of learning and their relationship with the computer as an educational aid.</span>


1975 ◽  
Vol 69 (2) ◽  
pp. 49-61
Author(s):  
Leslie L. Clark

This overview of the past, present, and future of research and development related to severely visually impaired persons covers the following subjects: documentation, creation of an armamentarium of aids (including both ordinary and highly sophisticated devices), the financing of R&D, the problem of technology transfer, dealing with change, the need for better theoretical models, and new definitions of the reality in which severely visually impaired individuals and those who work with them and for their benefit find themselves.


Philosophia ◽  
2018 ◽  
Vol 47 (4) ◽  
pp. 1011-1021
Author(s):  
Giacomo Andreoletti ◽  
Giuliano Torrengo

2018 ◽  
Vol 17 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Moshe Farjoun

This essay broadens the conversation on the state of organizational contradictions and paradox research by turning to dialectics—a time-honored, living perspective on social processes and relations, which continues to influence our understanding of the past, present, and future. Dialectics distinctive relational process worldview sets it apart from approaches stressing equilibrium, linearity, and coherence, making it highly relevant to a world in flux. I propose that dialectics is already present in strategy research and in contemporary business, and can become even more central to strategy, addressing core questions in the field and propelling it in new directions. Strategy scholars can draw on dialectics principles as a generative tool kit to construct new theories and managerial tools. Dialectics can also be used as a theoretical lens to understand emerging empirical phenomena such as the rapid advent of artificial intelligence. Finally, dialectics critical stance and philosophical grounding makes it a particularly attractive perspective for challenging existing theoretical models and for considering alternatives.


Author(s):  
Fabio Cardone ◽  
Gianni Albertini ◽  
Domenico Bassani

Abstract A torsional-antenna and a log-periodic antenna are used as a source and an analyzer, respectively, to investigate the possible anomalies of an electro-magnetic field. An unexpected isotropic signal has been detected using those torsion angles, which correspond to a breakdown of the Local Lorentz Invariance, which was found in the past. This coincidence is interpreted as the recovery of a lost symmetry by torqueing the antenna, thus putting in evidence that this Lorentz violation is of angular nature. Introducing a new physical dimension—not only a mathematical dimension as a way to rearrange some equations—is here proposed as a general rule to recover the lost symmetry.


2018 ◽  
Vol 2018 ◽  
pp. 1-31 ◽  
Author(s):  
M. G. Dainotti ◽  
R. Del Vecchio ◽  
M. Tarnopolski

The mechanism responsible for the prompt emission of gamma-ray bursts (GRBs) is still a debated issue. The prompt phase-related GRB correlations can allow discriminating among the most plausible theoretical models explaining this emission. We present an overview of the observational two-parameter correlations, their physical interpretations, and their use as redshift estimators and possibly as cosmological tools. The nowadays challenge is to make GRBs, the farthest stellar-scaled objects observed (up to redshift z=9.4), standard candles through well established and robust correlations. However, GRBs spanning several orders of magnitude in their energetics are far from being standard candles. We describe the advances in the prompt correlation research in the past decades, with particular focus paid to the discoveries in the last 20 years.


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