Search results for "energy [photon]"
showing 10 items of 18329 documents
Impurity behaviour in JET-ILW plasmas fuelled with gas and/or with pellets: a comparative study with the transport code COREDIV
2021
Abstract This study deals with the comparison of impurity behaviour in pellet and gas fuelled JET-ITER like wall pulses with the aim of finding the mechanisms leading to the generally observed higher concentration of tungsten in pellet fuelled plasmas. In fact, tungsten is the main high-Z impurity in the JET-ILW plasmas and is responsible for most of the radiative losses in the plasma core. Analysis of the experimental data pertaining to pulses at different plasma currents, different input power and different electron densities is integrated by numerical modelling with the self-consistent fluid transport code COREDIV. Experimentally, and numerically, the ratio between the radiated power in …
Study of very forward energy and its correlation with particle production at midrapidity in pp and p-Pb collisions at the LHC
2022
Journal of high energy physics 08(8), 86 (2022). doi:10.1007/JHEP08(2022)086
Lowest order perturbative quantum field theory calculations of bound state decay widths
2017
Alimman kertaluvun häiriöteoreettisia kvanttikenttäteorialaskuja sidottujen tilojen hajoamisleveyksille. Työssä lasketaan sidottujen tilojen hajoamisleveydet prosesseille $J/ \psi \rightarrow l^+ l^-$, $\eta_c \rightarrow gg$, $\text{O-Ps}\rightarrow \gamma\gamma\gamma$, $J/ \psi \rightarrow ggg$ ja $J/ \psi \rightarrow \gamma gg$. Prosessit lasketaan perturbatiivisen QED:n ja QCD:n alimmassa kertaluvussa. Laskuissa käydään läpi kolme erilaista tekniikkaa invariantin amplitudin käsittelemiseksi. Johdetut hajoamisleveystulokset käyvät yksiin kirjallisuudesta löytyvien tulosten kanssa. Lisäksi tarkastellaan kokeellisesti varmistettavissa olevia hajoamisleveyssuhteita. Teoreettiset ennusteet o…
Production of K∗ (892) 0 and ϕ(1020) in p–Pb collisions at √sNN = 5.02 TeV
2016
The production of K∗(892)0 and ϕ(1020) mesons has been measured in p–Pb collisions at √sNN = 5.02 TeV. K∗0 and ϕ are reconstructed via their decay into charged hadrons with the ALICE detector in the rapidity range −0.5<y<0. The transverse momentum spectra, measured as a function of the multiplicity, have a pT range from 0 to 15 GeV/c for K∗0 and from 0.3 to 21 GeV/c for ϕ. Integrated yields, mean transverse momenta and particle ratios are reported and compared with results in pp collisions at s√ = 7 TeV and Pb–Pb collisions at √sNN = 2.76 TeV. In Pb–Pb and p–Pb collisions, K∗0 and ϕ probe the hadronic phase of the system and contribute to the study of particle formation mechanisms by compar…
A study of Type B uncertainties associated with the photoelectric effect in low-energy Monte Carlo simulations
2021
The goal of this manuscript is to estimate Type B uncertainties in absorbed-dose calculations arising from the different implementations in current state-of-the-art Monte Carlo codes of low-energy photon cross-sections (<200 keV). Monte Carlo simulations are carried out using three codes widely used in the low-energy domain: PENELOPE-2018, EGSnrc, and MCNP. Mass energy-absorption coefficients for water, air, graphite, and their respective ratios; absorbed dose; and photon-fluence spectra are considered. Benchmark simulations using similar cross-sections have been performed. The differences observed between these quantities when different cross-sections are considered are taken to be a go…
Study of scintillation light collection, production and propagation in a 4 tonne dual-phase LArTPC
2020
The $3 \times 1 \times 1$ m$^3$ demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to provide precise timing capabilities. The performances of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.
Momentum distributions of cosmic relics: Improved analysis
2022
We solve coupled momentum-dependent Boltzmann equations for the phase space distribution of cosmic relic particles, without resorting to approximations of assuming kinetic equilibrium or neglecting backscattering or elastic interactions. Our method is amendable to precision numerical computations. To test it, we consider two benchmark models where the momentum dependence of dark matter distribution function is potentially important: a real singlet scalar extension near the Higgs resonance and a sterile neutrino dark matter model with a singlet scalar mediator. The singlet scalar example shows that the kinetic equilibrium may hold surprisingly well even near sharp resonances. However, the in…
Self-interacting dark matter and cosmology of a light scalar mediator
2015
We consider a fermionic dark matter candidate interacting via a scalar mediator coupled with the Standard Model through a Higgs portal. We consider general setting including both scalar and pseudoscalar interactions between the scalar and fermion, and illustrate the relevant features for dark matter abundance, direct search limits and collider constraints. The case where dark matter has a self-interaction strength $\left\langle \sigma_V \right\rangle/m_\psi \sim 0.1-1 \,\mathrm{cm}^2/\mathrm{g}$ is strongly constrained, in particular by the Big Bang Nucleosynthesis. We show that these constraints can be alleviated by introducing a new light sterile neutrino $N$. The allowed region for the e…
Recent results on Heavy-Ion induced reactions of interest for 0νββ decay
2019
An updated overview of recent results on Heavy-Ion induced reactions of interest for neutrinoless double beta decay is reported in the framework of the NUMEN project. The NUMEN idea is to study heavy-ion induced Double Charge Exchange (DCE) reactions with the aim to get information on the nuclear matrix elements for neutrinoless double beta (0νββ) decay. Moreover, to infer the neutrino average masses from the possible measurement of the half- life of 0νββ decay, the knowledge of the nuclear matrix elements is a crucial aspect. peerReviewed
Extensions of the standard model scalar sector and constraints from ccolliders and cosmology
2013
In this thesis we study the Higgs sector of the Standard Model and compare it to the latest data from the LHC and Tevatron experiments. Then we consider two extensions of the Higgs sector. First we extend the Standard Model Higgs sector with one real SU(2) singlet and then we consider two-Higgs- doublet model and extend also it with one real singlet. In both extensions the singlet scalar is considered as a potential dark matter candidate. We find that the parameter space of the so called two-Higgs-doublet-inert-singlet model includes regions which could provide a dark matter candidate which constitutes significant amount of the total dark matter mass density.