Embedded Files
Liquid xenon detectors for particle physics and astrophysics
E. Aprile, T. Doke
This article reviews the progress made over the last 20 years in the development and applications of liquid xenon detectors in particle physics, astrophysics, and medical imaging experiments. A summary of the fundamental properties of liquid xenon as radiation detection medium, in light of the most current theoretical and experimental information is first provided. After an introduction of the different type of liquid xenon detectors, a review of past, current, and future experiments using liquid xenon to search for rare processes and to image radiation in space and in medicine is given. Each application is introduced with a survey of the underlying scientific motivation and experimental requirements before reviewing the basic characteristics and expected performance of each experiment. Within this decade it appears likely that large volume liquid xenon detectors operated in different modes will contribute to answering some of the most fundamental questions in particle physics, astrophysics, and cosmology, fulfilling the most demanding detection challenges. From detectors based solely on liquid xenon .LXe scintillation, such as in the MEG experiment for the search of the rare “.→e” decay, currently the largest liquid xenon detector in operation, and in the XMASS experiment for dark matter detection, to the class of time projection chambers which exploit both scintillation and ionization of LXe, such as in the XENON dark matter search experiment and in the Enriched Xenon Observatory for neutrinoless double beta decay, unrivaled performance and important contributions to physics in the next few years are anticipated.
Links : https://journals.aps.org/rmp/pdf/10.1103/RevModPhys.82.2053
Cross-correlation of weak lensing and gamma rays: implications for the nature of dark matter
Tilman Tröster, Stefano Camera, Mattia Fornasa, Marco Regis, Ludovic van Waerbeke, Joachim Harnois-Déraps, Shin'ichiro Ando, Maciej Bilicki, Thomas Erben, Nicolao Fornengo, Catherine Heymans, Hendrik Hildebrandt, Henk Hoekstra, Konrad Kuijken, Massimo Viola
We measure the cross-correlation between Fermi-LAT gamma-ray photons and over 1000 deg2 of weak lensing data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), the Red Cluster Sequence Lensing Survey (RCSLenS), and the Kilo Degree Survey (KiDS). We present the first measurement of tomographic weak lensing cross-correlations and the first application of spectral binning to cross-correlations between gamma rays and weak lensing. The measurements are performed using an angular power spectrum estimator while the covariance is estimated using an analytical prescription. We verify the accuracy of our covariance estimate by comparing it to two internal covariance estimators. Based on the non-detection of a cross-correlation signal, we derive constraints on weakly interacting massive particle (WIMP) dark matter. We compute exclusion limits on the dark matter annihilation cross-section ⟨σannv⟩, decay rate Γdec, and particle mass mDM. We find that in the absence of a cross-correlation signal, tomography does not significantly improve the constraining power of the analysis. Assuming a strong contribution to the gamma-ray flux due to small-scale clustering of dark matter and accounting for known astrophysical sources of gamma rays, we exclude the thermal relic cross-section for masses of mDM≲20 GeV.
Links : https://arxiv.org/abs/1611.03554
Realistic estimation for the detectability of dark matter sub-halos with Fermi-LAT
Francesca Calore, Valentina De Romeri, Mattia Di Mauro, Fiorenza Donato, Federico Marinacci
Numerical simulations of structure formation have recorded a remarkable progress in the recent years, in particular due to the inclusion of baryonic physics evolving with the dark matter component. We generate Monte Carlo realizations of the dark matter sub-halo population based on the results of the recent hydrodynamical simulation suite of Milky Way-sized galaxies. We then simulate the gamma-ray sky for both the setup of the 3FGL and 2FHL Fermi Large Area Telescope (LAT) catalogs, including the contribution from the annihilation of dark matter in the sub-halos. We find that the flux sensitivity threshold strongly depends on the particle dark matter mass, and more mildly also on its annihilation channel and the observation latitude. The results differ for the 3FGL and 2FHL catalogs, given their different energy thresholds. We also predict that the number of dark matter sub-halos among the unassociated sources is very small. A null number of detectable sub-halos in the Fermi-LAT 3FGL catalog would imply upper limits on the dark matter annihilation cross section into bb¯ of 2⋅10−26 (5⋅10−25) cm3/s with MDM= 50 (1000) GeV. We find less than one extended sub-halo in the Fermi-LAT 3FGL catalog. As a matter of fact, the differences in the spatial and mass distribution of sub-halos between hydrodynamic and dark matter-only runs do not have significant impact on the gamma-ray dark matter phenomenology.
Links : https://arxiv.org/abs/1611.03503
Spin-dependent WIMP-nucleon cross section limits from first data of PandaX-II experiment
Changbo Fu, Xiangyi Cui, Xiaopeng Zhou, Xun Chen, Yunhua Chen, Deqing Fang, Karl Giboni, Franco Giuliani, Ke Han, Xingtao Huang, Xiangdong Ji, Yonglin Ju, Siao Lei, Shaoli Li, Huaxuan Liu, Jianglai Liu, Yugang Ma, Yajun Mao, Xiangxiang Ren, Andi Tan, Hongwei Wang, Jiming Wang, Meng Wang, Qiuhong Wang, Siguang Wang, Xuming Wang, Zhou Wang, Shiyong Wu, Mengjiao Xiao, Pengwei Xie, Binbin Yan, Yong Yang, Jianfeng Yue, Hongguang Zhang, Tao Zhang, Li Zhao, Ning Zhou
We report new constrains on the spin-dependent WIMP-neutron and WIMP-proton cross sections using recently released data from the PandaX-II experiment, a dual phase liquid xenon dark matter experiment at the China JinPing Underground Laboratory, with a total exposure of 3.3×104 kg-day. Assuming a standard axial-vector spin-dependent WIMP interaction with 129Xe and 131Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c2 are set in all direct detection experiments, with a minimum upper limit of 4.1×10−41 cm2 at 90\% confidence level for a WIMP mass of 40 GeV/c2, representing more than a factor of two improvement on the best available limits at high masses
Links : https://arxiv.org/abs/1611.06553
Ultra High Energy Cosmic Rays & Super-heavy Dark Matter
Luca Marzola, Federico R Urban
We reanalyse the prospects for upcoming Ultra-High Energy Cosmic Ray experiments in connection with the phenomenology of Super-heavy Dark Matter. We identify a set of observables well suited to reveal a possible anisotropy in the High Energy Cosmic Ray flux induced by the decays of these particles, and quantify their performance via Monte Carlo simulations that mimic the outcome of near-future and next-generation experiments. The spherical and circular dipoles are able to tell isotropic and anisotropic fluxes apart at a confidence level as large as 4σ or 5σ, depending on the Dark Matter profile. The forward-to-backward flux ratio yields a comparable result for relatively large opening angles of about 40~deg, but it is less performing once a very large number of events is considered. We also find that an actual experiment employing these observables and collecting 300~events at 60~EeV would have a 50% chance of excluding isotropy against Super-heavy Dark Matter at a significance of at least 3σ
Nuclear emulsions for dark matter detection
Tadaaki Tani (Fuji Photo Film) , Tatsuhiro Naka (KMI, Nagoya)
On silver halide (AgX) emulsion grains (∼200 nm in diameter) for neutrino detection in OPERA project, a latent image center composed of a cluster of ≧4 Ag atoms is formed with ∼18 electron-hole pairs by current photographic process in each grain. According to the analysis in this paper, AgX emulsion grains (∼40 nm) for dark matter detection should behave quite differently, forming a latent image center under such extraordinary condition that as many as ∼1000 electrons and surplus positive holes are created for ∼10 femtoseconds (fs) in each grain, causing violent recombination and re-halogenation of Ag clusters. Therefore, it is necessary to strongly reduce the recombination and re-halogenation of Ag clusters in the nuclear emulsions for dark matter detection. Further proposals are made on the design of nuclear emulsions for dark matter detection.
Page updated
Google Sites
Report abuse