Epj Web of Conferences
About: Epj Web of Conferences is an academic journal published by EDP Sciences. The journal publishes majorly in the area(s): Physics & Neutron. It has an ISSN identifier of 2100-014X. It is also open access. Over the lifetime, 12844 publications have been published receiving 30563 citations. The journal is also known as: European physical journal web of conferences & The European physical journal conferences.
TL;DR: In this article, the authors proposed an approach for the detection of the Cosmic Neutrino Background (CνB) with the induced beta decay (IBD) method.
Abstract: In 1964 Penzias and Wilson detected the Cosmic Microwave Background (CMB). Its spectrum follows Planck's black body radiation formula and shows a remark- able constant temperature of T0γ ≈ 2.7 K independent of the direction. The present photon density is about 370 photons per cm 3 . The size of the hot spots, which deviates only in the fifth decimal of the temperature from the average value, tells us, that the uni- verse is flat. About 380 000 years after the Big Bang at a temperature of T0γ = 3000 K already in the matter dominated era the electrons combine with the protons and the 4 He and the photons move freely in the neutral universe. So the temperature and distribution of the photons give us information of the universe 380 000 years after the Big Bang. Information about earlier times can, in principle, be derived from the Cosmic Neutrino Background (CνB). The neutrinos decouple already 1 second after the Big Bang at a tem- perature of about 10 10 K. Today their temperature is ∼ 1.95 K and the average density is 56 electron-neutrinos per cm 3 . Registration of these neutrinos is an extremely challenging experimental problem which can hardly be solved with the present technologies. On the other hand it represents a tempting opportunity to check one of the key element of the Big Bang cosmology and to probe the early stages of the universe evolution. The search for the CνB with the induced beta decay νe + 3 H → 3 He+ e − is the topic of this contribution. The signal would show up by a peak in the electron spectrum with an energy of the neu- trino mass above the Q value. We discuss the prospects of this approach and argue that it is able to set limits on the CνB density in our vicinity. We also discuss critically ways to increase with modifications of the present KATRIN spectrometer the source intensity by a factor 100, which would yield about 170 counts of relic neutrino captures per year. This would make the detection of the Cosmic Neutrino Background possible. Presently such an increase seems not to be possible. But one should be able to find an upper limit for the local density of the relic neutrinos (Cosmic Neutrino Background) in our galaxy.
TL;DR: In this article, a status report of the hadronic vacuum polarization effects for the muon g −2, to be considered as an update of , is presented, which concerns recent new inclusive R measurements from KEDR in the energy range 1.84 to 3.72 GeV.
Abstract: I present a status report of the hadronic vacuum polarization effects for the muon g –2, to be considered as an update of . The update concerns recent new inclusive R measurements from KEDR in the energy range 1.84 to 3.72 GeV. For the leading order contributions I find αμhad1=688.07±4.14688.77±3.38×10−10 based on e+ e- data [incl. τ data], αμhad2=−9.93±0.07×10−10 (NLO) and αμhad3=1.22±0.01×10−10 (NNLO). Collecting recent progress in the hadronic light-by-light scattering I adopt π 0 , η , η' [95 ± 12] + axial-vector [8 ± 3] + scalar [-6 ± 1] + π, K loops [-20 ± 5] + quark loops [22 ± 4] + tensor [1 ± 0] + NLO [3 ± 2] which yields αμ6lbl, had=103±29×10−11. With these updates I find αμexp−αμthe=31.3±7.7×10−10 a 4.1 σ deviation. Recent lattice QCD results and future prospects to improve hadronic contributions are discussed.
TL;DR: The Next Generation Transit Survey (NGTS) as mentioned in this paper is a ground-based sky survey designed to find transiting Neptunes and super-Earths, which will cover at least sixteen times the sky area of Kepler.
Abstract: The Next Generation Transit Survey (NGTS) is a new ground-based sky survey designed to find transiting Neptunes and super-Earths. By covering at least sixteen times the sky area of Kepler , we will find small planets around stars that are sufficiently bright for radial velocity confirmation, mass determination and atmospheric characterisation. The NGTS instrument will consist of an array of twelve independently pointed 20 cm telescopes fitted with red-sensitive CCD cameras. It will be constructed at the ESO Paranal Observatory, thereby benefiting from the very best photometric conditions as well as follow up synergy with the VLT and E-ELT. Our design has been verified through the operation of two prototype instruments, demonstrating white noise characteristics to sub-mmag photometric precision. Detailed simulations show that about thirty bright super-Earths and up to two hundred Neptunes could be discovered. Our science operations are due to begin in 2014.
TL;DR: In this article, an efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented, where coupled cascade equations are solved numerically by formulating them as matrix equation.
Abstract: An efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented. The coupled cascade equations are solved numerically by formulating them as matrix equation. The presented approach is very flexible and allows the use of different hadronic interaction models, realistic parametrizations of the primary cosmic-ray flux and the Earth's atmosphere, and a detailed treatment of particle interactions and decays. The power of the developed method is illustrated by calculating lepton flux predictions for a number of different scenarios. Cosmic rays entering the Earth's atmosphere produce a multitude of secondary particles in interactions with air nuclei. Some of the secondary particles decay into muons and neutrinos, which are not absorbed in the atmosphere and can reach particle detectors at ground level. The spectra of these leptons contains not only information about the primary cosmic rays, but also about the particle physics of their production and the properties of the traversed atmosphere. Furthermore, searches for high- energy neutrinos from astrophysical sources have to cope with a large flux of atmospheric leptons as background. A better understanding of this flux, in particular its dependence on zenith angle and the changing properties of the atmosphere will help to develop improved methods to identify astrophysical neutrino fluxes and also contribute to a better understanding of hadronic interactions at high energy.
TL;DR: In this paper, a general effective Lagrangian approach was used to obtain modelindependent limits on the dimension-six operators, as well as on several common new physics extensions, and discussed the status of electroweak constraints on new interactions.
Abstract: We briefly review the global Standard Model fit to electroweak precision data, and discuss the status of electroweak constraints on new interactions. We follow a general effective Lagrangian approach to obtain modelindependent limits on the dimension-six operators, as well as on several common new physics extensions.