15,381 research outputs found
Profile of multiboson signals
We investigate the visibility of signals characterised by wide bumps over a
smoothly falling background that cannot be accurately predicted by Monte Carlo
calculations. Examples of such are the wide bumps that triboson and quadriboson
resonance cascade decays would yield in diboson resonance searches in fully
hadronic final states. We find that the sensitivity to triboson bumps is rather
small: signals of a moderate size could be present in current data and yet
remain unnoticed. For quadriboson cascade decays the signals can hardly be
distinguished from the background in the current searches.Comment: LaTeX 17 pages. v2: fixed typos and comments added; journal versio
Direct optimisation of the discovery significance when training neural networks to search for new physics in particle colliders
We introduce two new loss functions designed to directly optimise the
statistical significance of the expected number of signal events when training
neural networks to classify events as signal or background in the scenario of a
search for new physics at a particle collider. The loss functions are designed
to directly maximise commonly used estimates of the statistical significance,
, and the Asimov estimate, . We consider their use in a toy
SUSY search with 30~fb of 14~TeV data collected at the LHC. In the case
that the search for the SUSY model is dominated by systematic uncertainties, it
is found that the loss function based on can outperform the binary cross
entropy in defining an optimal search region
Arthur C. Clarke - Prophet of the Space Age
Informally known as The Big Three, Arthur C. Clarke, Isaac Asimov, and Robert Heinlein were arguably the most famous science fiction writers of the latter half of the 20th century. Interestingly, they all knew each other, both professionally and personally; Clarke corresponded with the other two regularly for decades. He even had an informal agreement with Asimov, the Clarke-Asimov Treaty, that if asked, they agreed to say that Clarke was the better science fiction writer and Asimov the better science writer. But Clarke was much more than a science fiction writer - he was an engineer, a scientist, a futurist, a humanist, an explorer, and even an educator
Asymptotic formulae for likelihood-based tests of new physics
We describe likelihood-based statistical tests for use in high energy physics
for the discovery of new phenomena and for construction of confidence intervals
on model parameters. We focus on the properties of the test procedures that
allow one to account for systematic uncertainties. Explicit formulae for the
asymptotic distributions of test statistics are derived using results of Wilks
and Wald. We motivate and justify the use of a representative data set, called
the "Asimov data set", which provides a simple method to obtain the median
experimental sensitivity of a search or measurement as well as fluctuations
about this expectation.Comment: fixed typo in equations 75 & 7
Reassessing the sensitivity to leptonic CP violation
We address the validity of the usual procedure to determine the sensitivity
of neutrino oscillation experiments to CP violation. An explicit calibration of
the test statistic is performed through Monte Carlo simulations for several
experimental setups. We find that significant deviations from a
distribution with one degree of freedom occur for experimental setups with low
sensitivity to . In particular, when the allowed region to which
is constrained at a given confidence level is comparable to the whole
allowed range, the cyclic nature of the variable manifests and the premises of
Wilk's theorem are violated. This leads to values of the test statistic
significantly lower than a distribution at that confidence level. On
the other hand, for facilities which can place better constraints on
the cyclic nature of the variable is hidden and, as the potential of the
facility improves, the values of the test statistics first become slightly
higher than and then approach asymptotically a distribution. The role
of sign degeneracies is also discussed.Comment: 14 pages, 5 figures, RevTeX4. The discussion of the results has been
improved and considerably extended. Version accepted for publication in JHE
Determination of neutrino mass ordering in future Ge-based neutrinoless double-beta decay experiments
Motivated by recent intensive experimental efforts on searching for
neutrinoless double-beta decays, we perform a detailed analysis of the physics
potential of the experiments based on . Assuming no signals,
current and future experiments could place a lower limit on the half
life and , respectively. Then, how to report an
evidence for neutrinoless double-beta decays is addressed by following the
Bayesian statistical approach. For the first time, we present a quantitative
description of experimental power to distinguish between normal and inverted
neutrino mass orderings. Taking an exposure of
and a background rate of , we find that a moderate evidence for normal neutrino mass ordering
(i.e., with a Bayes factor given by or a
probability about according to the Jeffreys scale) can be achieved if
the true value of effective neutrino mass turns out to be
below .Comment: 16 pages, 7 figures, the Jeffreys scale used, more discussions added,
to appear in Phys. Rev.
Stellar Wakes from Dark Matter Subhalos
We propose a novel method utilizing stellar kinematic data to detect low-mass
substructure in the Milky Way's dark matter halo. By probing characteristic
wakes that a passing dark matter subhalo leaves in the phase space distribution
of ambient halo stars, we estimate sensitivities down to subhalo masses or below. The detection of such subhalos would have implications
for dark-matter and cosmological models that predict modifications to the
halo-mass function at low halo masses. We develop an analytic formalism for
describing the perturbed stellar phase-space distributions, and we demonstrate
through simulations the ability to detect subhalos using the phase-space model
and a likelihood framework. Our method complements existing methods for
low-mass subhalo searches, such as searches for gaps in stellar streams, in
that we can localize the positions and velocities of the subhalos today.Comment: 6 + 3 pages, 1 + 2 figures, code available at:
https://github.com/bsafdi/stellarWake
Science Fiction Transhumanism: Exegesis of the Foundation saga by Isaac Asimov
Este artículo analiza varias de las corrientes transhumanistas, como el singularitarianismo, inmortalismo, posgenerismo y abolicionismo, en la saga de la Fundación de Isaac Asimov. Partiendo de los quince libros que conforman dicha saga, se examina la visión de Asimov sobre estas ideas, y muestra cómo las
diferentes novelas tratan sus complejas implicaciones, ya que contrariamente a la interpretación más habitual, el autor fue mucho más allá de sus historias de robots al tratar temáticas transhumanistas.This article analyzes several transhumanist currents, like singularitarianism, immortalism, postgenderism and abolitionism, in the Foundation series of Isaac Asimov. On the basis of the 15 books that make up the saga, Asimov’s vision of these ideas is examined to show how these novels address their complex implications, because contrary to the usual interpretation, the author went far beyond his
robot stories for dealing with transhumanist topics
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