Search results for "background"
showing 10 items of 556 documents
Neutrinos below 100 TeV from the southern sky employing refined veto techniques to IceCube data
2020
Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atm…
Comparison between simulated and observed LHC beam backgrounds in the ATLAS experiment at E beam =4 TeV
2018
Results of dedicated Monte Carlo simulations of beam-induced background (BIB) in the ATLAS experiment at the Large Hadron Collider (LHC) are presented and compared with data recorded in 2012. During normal physics operation this background arises mainly from scattering of the 4 TeV protons on residual gas in the beam pipe. Methods of reconstructing the BIB signals in the ATLAS detector, developed and implemented in the simulation chain based on the FLUKA Monte Carlo simulation package, are described. The interaction rates are determined from the residual gas pressure distribution in the LHC ring in order to set an absolute scale on the predicted rates of BIB so that they can be compared qua…
Spectral shapes of forbidden argon β decays as background component for rare-event searches
2018
The spectral shape of the electrons from the two first-forbidden unique ${\beta }^{-}$ decays of 39Ar and 42Ar were calculated for the first time to the next-to-leading order. Especially the spectral shape of the 39Ar decay can be used to characterize this background component for dark matter searches based on argon. Alternatively, due to the low thresholds of these experiments, the spectral shape can be investigated over a wide energy range with high statistics and thus allow a sensitive comparison with the theoretical predictions, in particular at low electron energies where the shape of the computed β spectrum has a slight dependence on the value of the weak axial-vector coupling constan…
Nozīmes veidošana attēlos: lingvistiskā un paralingvistiskā perspektīva
2021
Darba mērķis ir izpētīt, kā attēlu nozīmi iespējams interpretēt noteiktā kontekstā. Pētījums reaģē uz galējās interpretācijas problemātiku un ierosina skatīt Čārlza Pīrsa zīmju teoriju kā instrumentu, kas ļauj analizēt nozīmes radīšanas un interpretācijas procesualitāti noteiktas situācijas un kultūras kontekstā. Tiek pētīti četri atšķirīgi attēlu gadījumi (Hilma af Klinta, Sajs Tvomblijs, Gerhards Rihters un Vija Celmiņa), piemērojot mainīgos konteksta lielumus un Pīrsa zīmju klasifikācijas. Vijas Celmiņas intervijas fonētiskā un runātā diskursa analīze liecina, ka mākslinieces runātais teksts var attīstīt uztvērēja priekšzinās…
Latest results from CUPID-0
2022
International audience; CUPID-0 is a pilot experiment in scintillating cryogenic calorimetry for the search of neutrino-less double beta decay. 26 ZnSe crystals were operated continuously in the first project phase (March 2017 - December 2018), demonstrating unprecedented low levels of background in the region of interest at the Q-value of $^{82}\rm{Se}$. From this successful experience comes a demonstration of full alpha to beta/gamma background separation, the most stringent limits on the $^{82}\rm{Se}$ neutrino-less double beta decay, as well as the most precise measurement of the $^{82}$Se half-life. After a detector upgrade, CUPID-0 began its second and last phase (June 2019 - February…
Microscopic calculation of the $\beta^-$ decays of $^{151}$Sm, $^{171}$Tm, and $^{210}$Pb with implications to detection of the cosmic neutrino backg…
2023
The electron spectral shapes corresponding to the low-$Q$ $\beta^-$-decay transitions $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(5/2^+_{\rm g.s.})$, $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(7/2^+_{1})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(1/2^-_{\rm g.s.})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(3/2^-_{1})$, $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(1^-_{\rm g.s.})$, and $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(0^-_{1})$ have been computed using beta-decay theory with several refinements for these first-forbidden nonunique (ff-nu) $\beta^-$ transitions. These ff-nu $\beta^-$ transitions have non-trivial electro…
All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems
2021
Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most s…
Nonlinear radial-harmonic correlation using binary decomposition for scale-invariant pattern recognition
2003
We introduce a new scale-invariant pattern-recognition method that uses nonlinear correlation. We applied several common linear correlations to images decomposed into disjoint binary images, which is very discriminant even when the target is embedded in strong noise. We combine our sliced orthogonal nonlinear generalized correlation method and the radial-harmonic expansion in order to achieve scale-invariant pattern recognition. The information from a radial harmonic for each binary slice of the reference object is combined with binary slices of the target. The method avoids the time-consuming process of finding expansion centers for the radial harmonics. The stability of the correlation pe…
Improved rotation invariant pattern recognition using circular harmonics of binary gray level slices
2000
We introduce a new rotation invariant pattern recognition method based on nonlinear correlation. The images are decomposed into disjoint binary slices and then correlated using the common linear correlation. This operation is very discriminant even when the target is embedded in strong noise. We extend our sliced orthogonal nonlinear generalized correlation method to rotation invariant pattern recognition by combining the information of a circular harmonic (CH) of each binary slice of the reference object with binary slices of the target. In addition to improved discrimination capability, the method avoids the time-consuming process of finding proper centers for the CHs. Results are present…
Analytical characteristics, applications and perspectives in thermal lens spectrometry
1993
Abstract The following selected aspects of thermal lens spectrometry are briefly outlined: fundamentals, sensitivity and background noise, detection approaches, flowing samples, multi-wavelength experiments, thermal lens circular dichroism, associated colateral phenomena and physico-chemical applications and requirements of analytical procedures. The state-of-the-art and problems encountered are discussed.