618 research outputs found
Absolute determination of D_s branching ratios and f_{D_s} extraction at a neutrino factory
A method for a direct measurement of the exclusive D_s branching ratios and
of the decay constant f_{D_s} with a systematical error better than 5% is
presented. The approach is based on the peculiar vertex topology of the
anti-neutrino induced diffractive charm events. The statistical accuracy
achievable with a neutrino factory is estimated
Heavy quark studies with nuclear emulsions
Emulsions have started particle physics with the discovery of natural
radioactivity by Becquerel in 1896. The development of the ``nuclear
emulsions'' made it possible to detect tracks of single particle and to perform
detailed measurements of their interactions. The discovery of the pion in 1947
was the first, spectacular demonstration of their unique features for the
direct observation of the production and decay of short-lived particles, with
negligible or very low background. In particular, these features are now
exploited for studies of heavy quark physics in experiments where nuclear
emulsions are combined with electronic detectors and profit is taken of the
remarkable technological progress in automated analysis. In these experiments,
neutrinos provide a selective probe for specific quark flavors. Interesting
results on charm production and decay are expected in the very near future.Comment: To be published on the book for the eightieth birthday of Roberto
Salmeron, World Scientifi
Prediction of charm-production fractions in neutrino interactions
The way a charm-quark fragments into a charmed hadron is a challenging
problem both for the theoretical and the experimental particle physics.
Moreover, in neutrino induced charm-production, peculiar processes occur such
as quasi-elastic and diffractive charm-production which make the results from
other experiments not directly comparable. We present here a method to extract
the charmed fractions in neutrino induced events by using results from
, , experiments while taking into account the
peculiarities of charm-production in neutrino interactions. As results, we
predict the fragmentation functions as a function of the neutrino energy and
the semi-muonic branching ratio, , and compare them with the available
data
Pinning Control of Higher Order Nonlinear Network Systems
In this letter, we study the problem of controlling via pinning the motion of nonlinear network systems of any order whose dynamics are in controllable canonical form. Different from existing works that either focus on spontaneous synchronization, assume linear dynamics or rely on dynamics cancellation, here we provide a constructive method to prove pinning controllability towards the desired trajectory selected by the pinner. We introduce an algorithmic procedure that associates to any connected topology a suitable Lyapunov function for the network system. The approach is demonstrated on an illustrative example
A search for Z' in muon neutrino associated charm production
In many extensions of the Standard Model the presence of an extra neutral
boson, Z', is invoked. A precision study of weak neutral-current exchange
processes involving only second generation fermions is still missing. We
propose a search for Z' in muon neutrino associated charm production. This
process only involves Z' couplings with fermions from the second generation. An
experimental method is thoroughly described using an ideal detector. As an
application, the accuracy reachable with present and future experiments has
been estimated.Comment: 13 pages, 3 figures, late
Modeling Human Migration Under Environmental Change: A Case Study of the Effect of Sea Level Rise in Bangladesh
Sea level rise (SLR) could have catastrophic consequences worldwide. More than 600 million people currently living in coastal areas may see their livelihood at risk and choose to migrate in the near future. Predicting when, how, and where people could migrate under environmental change is critical to devise effective policy initiatives and improve our preparedness. Here, we propose a modeling framework to predict the effect of SLR on migration patterns from easily accessible geographic and demographic data. The framework adapts the radiation model to capture unwillingness or inability to migrate of affected residents, as well as return migration and cascading effects in migration patterns. We apply the mathematical model to study internal migration in Bangladesh, where we predict a complex and counterintuitive landscape of migration patterns between districts. Our predictions indicate that the impact of SLR on 816,000 people by 2050 will trigger cascading effects in migration patterns throughout the entire country. The population of each of the 64 districts will change, leading to a total variation of 1.3 million people. Migration from inundated regions in the center will trigger non-trivial patterns, including a reduction in the population of the district of the capital Dhaka
Quantifying the role of the COVID-19 pandemic in the 2020 U.S. presidential elections
In the media, a prevalent narrative is that the incumbent United States President Donald J. Trump lost the 2020 elections because of the way he handled the COVID-19 pandemic. Quantitative evidence to support this narrative is, however, limited. We put forward a spatial, information-theoretic approach to critically examine the link between voting behavior and COVID-19 incidence in the 2020 presidential elections. The approach overcomes classical limitations of traditional regression analysis, where it does not require an underlying mathematical model and it can capture nonlinear interactions. From the analysis of county-level data, we uncovered a robust association between voting behavior and prevalence of COVID-19 cases. Surprisingly, such an association points in the opposite direction from the accepted narrative: in counties that experienced less COVID-19 cases, the incumbent President lost more ground to his opponent, now President Joseph R. Biden Jr. A tenable explanation of this observation is the different attitude of liberal and conservative voters toward the pandemic, which led to more COVID-19 spreading in counties with a larger share of republican voters
Distributed Discontinuous Coupling for Convergence in Heterogeneous Networks
In this letter, we propose the use of a distributed discontinuous coupling protocol to achieve convergence and synchronization in networks of non-identical nonlinear dynamical systems. We show that the synchronous dynamics is a solution to the average of the nodes' vector fields, and derive analytical estimates of the critical coupling gains required to achieve convergence
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