Search results for "Interactions"
showing 10 items of 1963 documents
Demonstration of background rejection using deep convolutional neural networks in the NEXT experiment
2021
[EN] Convolutional neural networks (CNNs) are widely used state-of-the-art computer vision tools that are becoming increasingly popular in high-energy physics. In this paper, we attempt to understand the potential of CNNs for event classification in the NEXT experiment, which will search for neutrinoless double-beta decay in Xe-136. To do so, we demonstrate the usage of CNNs for the identification of electron-positron pair production events, which exhibit a topology similar to that of a neutrinoless double-beta decay event. These events were produced in the NEXT-White high-pressure xenon TPC using 2.6 MeV gamma rays from a Th-228 calibration source. We train a network on Monte Carlo-simulat…
A precision measurement of charm dimuon production in neutrino interactions from the NOMAD experiment
2013
We present our new measurement of the cross-section for charm dimuon production in neutrino iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15 344 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample - about 9 x 10(6) events after all analysis cuts - and the high resolution NOMAD detector to constrain the total systematic uncertainty on the ratio of charm dimuon to inclusive Charged Current (CC) cross-sections to similar to 2%. We also perform a fit to the NOMAD data to extract the charm production parameters and the strange quark sea…
Strangeness-changing scalar form factors
2001
30 páginas, 2 tablas, 10 figuras.-- arXiv:hep-ph/0110193v1
Search for right-handed W bosons in top quark decay
2005
We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of $t\bar{t}$ events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb^-1, collected by the DO detector at the Fermilab Tevatron $p\bar{p}$ Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the $t\bar{t}$ and decay products, which allows for the measurement of the leptonic decay angle $\theta^*$ for each event. By comparing the $\cos\theta^*$ distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00+-0.13(stat)+-0.07(syst). This …
Nuclear response functions in homogeneous matter with finite range effective interactions
2005
The question of nuclear response functions in a homogeneous medium is examined. A general method for calculating response functions in the random phase approximation (RPA) with exchange is presented. The method is applicable for finite-range nuclear interactions. Examples are shown in the case of symmetric nuclear matter described by a Gogny interaction. It is found that the convergence of the results with respect to the multipole truncation is quite fast. Various approximation schemes such as the Landau approximation, or the Landau approximation for the exchange terms only, are discussed in comparison with the exact results.
Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature
1998
The 1996 data taking of the SMC experiment used polarized protons to measure the spin-dependent structure function g(1) of the proton. Three liters of solid granular ammonia were irradiated at the Bonn electron linac in order to create the paramagnetic radicals which are needed for polarizing the protons. Proton polarizations of +/- (90 +/- 2.5)% were routinely reached. An analysis based on a theoretical line shape for spin-1. systems with large quadrupolar broadening was developed which allowed the nitrogen polarization in the ammonia to be determined with a 10% relative error. The measured quadrupolar coupling constant of N-14 agrees well with earlier extrapolated values. The polarization…
Neutrino-nuclear responses for astro-neutrinos, single beta decays and double beta decays
2019
Abstract Neutrino–nuclear responses associated with astro-neutrinos, single beta decays and double beta decays are crucial in studies of neutrino properties of interest for astro-particle physics. The present report reviews briefly recent studies of the neutrino–nuclear responses from both experimental and theoretical points of view in order to obtain a consistent understanding of the many facets of the neutrino–nuclear responses. Subjects discussed in this review include (i) experimental studies of neutrino–nuclear responses by means of single beta decays, charge-exchange nuclear reactions, muon- photon- and neutrino–nuclear reactions, and nucleon-transfer reactions, (ii) implications of a…
Padé approximants and the prediction of non-perturbative parameters in particle physics
2010
Conference on Approximation and extrapolation of Convergent and Divergent Sequences and Series Luminy, FRANCE, SEP 28-OCT 02, 2009
Sex-Specific Differences in the Control of Serum Concentrations of Glycine in Subjects with Metabolic Syndrome and Mendelian Randomization Analysis f…
2020
OBJECTIVES: Glycine is a novel circulating marker for metabolic diseases associated with lower type-2 diabetes and protection against obesity in some studies. Circulating glycine levels are genetically determined under the control of several loci. The locus most strongly associated is the carbamoyl-phosphate synthase I (CPS1). Interestingly, some sex-specific genome-wide association studies (GWAS) showed differences in the effect of the main single nucleotide polymorphisms (SNPs) in this locus on glycine levels (significant sex * CPS1 interactions). However, the potential mechanisms explaining this sex-heterogeneity are unknown. Therefore, our aims were: 1) to analyze whether the sex * CPS1…
Attraction of egg-killing parasitoids toward induced plant volatiles in a multi-herbivore context
2015
In response to insect herbivory, plants emit volatile organic compounds which may act as indirect plant defenses by attracting natural enemies of the attacking herbivore. In nature, plants are often attacked by multiple herbivores, but the majority of studies which have investigated indirect plant defenses to date have focused on the recruitment of different parasitoid species in a single-herbivore context. Here, we report our investigation on the attraction of egg parasitoids of lepidopteran hosts (Trichogramma brassicae and T. evanescens) toward plant volatiles induced by different insect herbivores in olfactometer bioassays. We used a system consisting of a native crucifer, Brassica nigr…