Library of SM and anomalous WWgamma couplings for the e+e- -> f \bar{f} n\gamma Monte Carlo programs

A brief description of the library of the Standard Model and anomalous WWgamma coupling contribution to the matrix element for e+e- -> \nu \bar{\nu} n\gamma process is given. It can be used with any Monte Carlo program for e+e- -> f \bar f n\gamma processes. A working example of the application for the KORALZ version 4.04 is also provided.Comment: 1+5 pages (LaTeX

Charged Cosmic Rays and Photons in AMS

AMS is a particle physics experiment in space. During at least 3 year operation on the International Space Station, the AMS-02 detector will provide atmospheric background-free data on fluxes and composition of the Galactic Cosmic Rays with unprecedented precision. The searches for the exotic components of the Cosmic radiation such as primordial antimatter or dark matter signals will also be performed. The new results will allow to improve the knowledge of the Cosmic Ray production, acceleration and propagation mechanisms, and to constrain various models

Sagittarius dwarf spheroidal galaxy observed by H.E.S.S

Dwarf spheroidal galaxies are characterized by a large measured mass-to-light ratio and are not expected to be the site of high-luminosity non-thermal high-energy gamma-ray emissions. Therefore they are among the most promising candidates for indirect searches of dark matter particle annihilation signals in gamma rays. The Sagittarius dwarf spheroidal galaxy has been regularly observed by the High Energy Stereoscopic System (H.E.S.S.) of Cherenkov telescopes for more than 90 hours, searching for TeV gamma-ray emission from annihilation of dark matter particles. In absence of a significant signal, new constraints on the annihilation crosssection of the dark matter particles applicable for Majorana Weakly Interacting Massive Particles (WIMPs) are derived.Comment: In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil

Probe of Lorentz Invariance Violation effects and determination of the distance of PG 1553+113

The high frequency peaked BL Lac object PG 1553+113 underwent a flaring event in 2012. The High Energy Stereoscopic System (H.E.S.S.) observed this source for two consecutive nights at very high energies (VHE, $E>$100~GeV). The data show an increase of a factor of three of the flux with respect to archival measurements with the same instrument and hints of intra-night variability. The data set has been used to put constraints on possible Lorentz invariance violation (LIV), manifesting itself as an energy dependence of the velocity of light in vacuum, and to set limits on the energy scale at which Quantum Gravity effects causing LIV may arise. With a new method to combine H.E.S.S. and Fermi large area telescope data, the previously poorly known redshift of PG 1555+113 has been determined to be close to the value derived from optical measurements.Comment: 2014 Fermi Symposium proceedings - eConf C14102.

Constraints on anomalous quartic gauge boson couplings from photon pair events from 189 GeV to 209 GeV

The analysis of acoplanar photon pair events with missing energy and transverse momentum measured in the ALEPH detector at centre-of-mass energies between 189 and 209 GeV, leads to constraints on anomalous quartic gauge couplings in the reaction $e^{+}e^{-} \rightarrow \nu \bar{\nu} \gamma \gamma$. From 1-parameter fits, and using only the cross-section variation in the low missing mass region, the following 95 % CL constraints are obtained on the anomalous parameters $a_{0}/ \Lambda^{2}$ and $a_{c}/ \Lambda^{2}$: $-0.029 GeV^{-2} < a_{0}/ \Lambda^{2} < 0.026 GeV^{-2}$, $-0.080 GeV^{-2} < a_{c}/ \Lambda^{2} < 0.075 GeV^{-2}$

A multivariate analysis approach for the Imaging atmospheric Cerenkov Telescopes System H.E.S.S.

International audienceWe present a multivariate classification approach applied to the analysis of data from the H.E.S.S. Very High Energy (VHE) gamma-ray IACT stereoscopic system. This approach combines three complementary analysis methods already successfully applied in the H.E.S.S. data analysis. The proposed approach, with the combined effective estimator Xeff, is conceived to improve the signal-to-background ratio and therefore particularly relevant to the morphological studies of faint extended sources

Search for Gamma-ray Line Signatures with H.E.S.S

Many results from astrophysical observations point to a 27% contribution of non-baryonic dark matter to the mass-energy budget of the universe. Although still elusive, strongly motivated candidates in form of weakly interacting massive particles could explain the nature of dark matter, and their annihilation or decay would give rise to detectable signatures in gamma-rays. In 2012, the H.E.S.S. collaboration started taking data with the largest imaging atmospheric Cherenkov telescope in the world which significantly lowered the energy threshold of the already operational four-telescope system. In particular, due to its location and improved performance at low energies, the H.E.S.S. experiment is now in a position to extend the search for dark matter line signals down to the 100 GeV mass range. The sensitivity to line searches with a new full likelihood approach will be discussed and preliminary results from observations with the second phase of H.E.S.S. will be presented.Comment: ICRC 2015 Conference Proceeding, 8 pages, 5 figures, 1 tabl