arXiv subjects

Laura Baudis

Publications and source records attributed to Laura Baudis.

52 records · Page 3Linked to original sources

arXiv2011

Background Measurements in the Gran Sasso Underground Laboratory

The gamma background flux below 3000 keV in the Laboratori Nazionali del Gran Sasso (LNGS), Italy, has been measured using a 3" diameter NaI(Tl) detector at different underground positions: In hall A, hall B, the interferometer tunnel, and inside the Large Volume Detector (LVD). The integrated flux is 0.3--0.4 s$^{-1}$cm$^{-2}$ at the first three locations, and is lower by two orders of magnitude inside LVD. With the help of Monte Carlo simulations for every location, the contribution of the individual primordial isotopes to the background has been determined. Using an 11" diameter NaI(Tl) detector, the background neutron flux in the LNGS interferometer tunnel has been estimated. Within the uncertainties, the result agrees with those from other neutron measurements in the main halls.

astro-ph.IM↗

arXiv2010

DARWIN: dark matter WIMP search with noble liquids

DARWIN (DARk matter WImp search with Noble liquids) is an R&D and design study towards the realization of a multi-ton scale dark matter search facility in Europe, based on the liquid argon and liquid xenon time projection chamber techniques. Approved by ASPERA in late 2009, DARWIN brings together several European and US groups working on the existing ArDM, XENON and WARP experiments with the goal of providing a technical design report for the facility by early 2013. DARWIN will be designed to probe the spin-independent WIMP-nucleon cross section region below 10-47cm^2 and to provide a high-statistics measurement of WIMP interactions in case of a positive detection in the intervening years. After a brief introduction, the DARWIN goals, components, as well as its expected physics reach will be presented.

astro-ph.IM↗

arXiv2009

Dark Matter Disc Enhanced Neutrino Fluxes from the Sun and Earth

As disc galaxies form in a hierarchical cosmology, massive merging satellites are preferentially dragged towards the disc plane. The material accreted from these satellites forms a dark matter disc that contributes 0.25 - 1.5 times the non-rotating halo density at the solar position. Here, we show the importance of the dark disc for indirect dark matter detection in neutrino telescopes. Previous predictions of the neutrino flux from WIMP annihilation in the Earth and the Sun have assumed that Galactic dark matter is spherically distributed with a Gaussian velocity distribution, the standard halo model. Although the dark disc has a local density comparable to the dark halo, its higher phase space density at low velocities greatly enhances capture rates in the Sun and Earth. For typical dark disc properties, the resulting muon flux from the Earth is increased by three orders of magnitude over the SHM, while for the Sun the increase is an order of magnitude. This significantly increases the sensitivity of neutrino telescopes to fix or constrain parameters in WIMP models. The flux from the Earth is extremely sensitive to the detailed properties of the dark disc, while the flux from the Sun is more robust. The enhancement of the muon flux from the dark disc puts the search for WIMP annihilation in the Earth on the same level as the Sun for WIMP masses < 100 GeV.

astro-ph.HE↗

arXiv2009

Status and Sensitivity Projections for the XENON100 Dark Matter Experiment

The XENON experimental program aims to detect cold dark matter particles via their elastic collisions with xenon nuclei in two-phase time projection chambers (TPCs). We are currently testing a new TPC at the 100 kg scale, XENON100. This new, ultra-low background detector, has a total of 170 kg of xenon (65 kg in the target region and 105 kg in the active shield). It has been installed at the Gran Sasso Underground Laboratory and is currently in commissioning phase. We review the design and performance of the detector and its associated systems, present status, preliminary calibration results, background prediction and projected sensitivity. With a 6000 kg-day background-free exposure, XENON100 will reach a sensitivity to spin-independent WIMP-nucleon cross section of 2e-45 cm2 by the end of 2009. We also discuss our plan to upgrade the XENON100 experiment to improve the sensitivity by another order of magnitude by 2012.

astro-ph.IM↗

arXiv2008

Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC (IDM 2008 proceeding)

We explore the phenomenology of Kaluza-Klein (KK) dark matter in very general models with universal extra dimensions (UEDs), emphasizing the complementarity between high-energy colliders and dark matter direct detection experiments. In models with relatively small mass splittings between the dark matter candidate and the rest of the (colored) spectrum, the collider sensitivity is diminished, but direct detection rates are enhanced. UEDs provide a natural framework for such mass degeneracies. We consider both 5-dimensional and 6-dimensional non-minimal UED models, and discuss the detection prospects for various KK dark matter candidates: the KK photon γ_1 (5D) the KK Z-boson Z_1 (5D) and the spinless KK photon γ_H (6D). We combine collider limits such as electroweak precision data and expected LHC reach, with cosmological constraints from WMAP and the sensitivity of current or planned direct detection experiments. Allowing for general mass splittings, we show that neither colliders, nor direct detection experiments by themselves can explore all of the relevant KK dark matter parameter space. Nevertheless, they probe different parameter space regions and the combination of the two types of constraints can be quite powerful. For example, in the case of γ_1 in 5D UEDs the relevant parameter space will be almost completely covered by the combined LHC and direct detection sensitivities expected in the near future.

hep-ph↗

arXiv2008

Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC

We explore the phenomenology of Kaluza-Klein (KK) dark matter in very general models with universal extra dimensions (UEDs), emphasizing the complementarity between high-energy colliders and dark matter direct detection experiments. In models with relatively small mass splittings between the dark matter candidate and the rest of the (colored) spectrum, the collider sensitivity is diminished, but direct detection rates are enhanced. UEDs provide a natural framework for such mass degeneracies. We consider both 5-dimensional and 6-dimensional non-minimal UED models, and discuss the detection prospects for various KK dark matter candidates: the KK photon $γ_1$, the KK $Z$-boson $Z_1$, the KK Higgs boson $H_1$ and the spinless KK photon $γ_H$. We combine collider limits such as electroweak precision data and expected LHC reach, with cosmological constraints from WMAP, and the sensitivity of current or planned direct detection experiments. Allowing for general mass splittings, we show that neither colliders, nor direct detection experiments by themselves can explore all of the relevant KK dark matter parameter space. Nevertheless, they probe different parameter space regions, and the combination of the two types of constraints can be quite powerful. For example, in the case of $γ_1$ in 5D UEDs the relevant parameter space will be almost completely covered by the combined LHC and direct detection sensitivities expected in the near future.

hep-ph↗

arXiv2007

Direct Detection of Cold Dark Matter

We know from cosmological and astrophysical observations that more than 80% of the matter density in the Universe is non-luminous, or dark. This non-baryonic dark matter could be composed of neutral, heavy particles, which were non-relativistic, or 'cold', when they decoupled from ordinary matter. I will review the direct detection methods of these hypothetical particles via their interactions with nuclei in ultra-low background, deep underground experiments. The emphasis is on most recent results and on the status of near future projects.

astro-ph↗

arXiv2007

The XENON10 WIMP Search Experiment at the Gran Sasso Underground Laboratory

XENON10 is a new direct dark matter detection experiment using liquid xenon as target for weakly interacting, massive particles (WIMPs). A two-phase (liquid/gas) time projection chamber with 15 kg fiducial mass has been installed in a low-background shield at the Gran Sasso Underground Laboratory in July 2006. After initial performance tests with various calibration sources, the science data run started on August 24, 2006. The detector has been running stably since then, and a full analysis of more than 75 live days of WIMP search data is now in progress. We present first results on gamma and neutron calibration runs, as well as a preliminary analysis of a subset of the WIMP search data.

astro-ph↗

arXiv2006

Direct Dark Matter Searches with CDMS and XENON

The Cryogenic Dark Matter Search (CDMS) and XENON experiments aim to directly detect dark matter in the form of weakly interacting massive particles (WIMPs) via their elastic scattering on the target nuclei. The experiments use different techniques to suppress background event rates to the minimum, and at the same time, to achieve a high WIMP detection rate. The operation of cryogenic Ge and Si crystals of the CDMS-II experiment in the Soudan mine yielded the most stringent spin-independent WIMP-nucleon cross-section (~10^{-43} cm^2) at a WIMP mass of 60 GeV/c^2. The two-phase xenon detector of the XENON10 experiment is currently taking data in the Gran Sasso underground lab and promising preliminary results were recently reported. Both experiments are expected to increase their WIMP sensitivity by a one order of magnitude in the scheduled science runs for 2007.

astro-ph↗

arXiv2006

CDMS, Supersymmetry and Extra Dimensions

The CDMS experiment aims to directly detect massive, cold dark matter particles originating from the Milky Way halo. Charge and lattice excitations are detected after a particle scatters in a Ge or Si crystal kept at ~30 mK, allowing to separate nuclear recoils from the dominating electromagnetic background. The operation of 12 detectors in the Soudan mine for 75 live days in 2004 delivered no evidence for a signal, yielding stringent limits on dark matter candidates from supersymmetry and universal extra dimensions. Thirty Ge and Si detectors are presently installed in the Soudan cryostat, and operating at base temperature. The run scheduled to start in 2006 is expected to yield a one order of magnitude increase in dark matter sensitivity.

astro-ph↗

arXiv2005

Dark Matter Searches

More than 90% of matter in the Universe could be composed of heavy particles, which were non-relativistic, or 'cold', when they froze-out from the primordial soup. I will review current searches for these hypothetical particles, both via interactions with nuclei in deep underground detectors, and via the observation of their annihilation products in the Sun, galactic halo and galactic center.

astro-ph↗

arXiv2005

Underground Searches for Cold Relics of the Early Universe

We have strong evidence on all cosmic scales, from galaxies to the largest structures ever observed, that there is more matter in the universe than we can see. Galaxies and clusters would fly apart unless they would be held together by material which we call dark, because it does not shine in photons. Although the amount of dark matter and its distribution are fairly well established, we are clueless regarding its composition. Leading candidates are Weakly Interacting Massive Particles (WIMPs), which are 'cold' thermal relics of the Big Bang, ie moving non-relativistically at the time of structure formation. These particles can be detected via their interaction with nuclei in deep-underground, low-background detectors. Experiments dedicated to observe WIMP interactions for the first time reach sensitivities allowing to probe the parameter space predicted by supersymmetric theories of particle physics. Current results of high sensitivity direct detection experiments are discussed and the most promising projects of the future are presented. If a stable new particle exists at the weak scale, it seems likely to expect a discovery within this decade.

astro-ph↗

arXiv2004

Direct Detection Constraints on Superheavy Dark Matter

The dark matter in the Universe might be composed of superheavy particles (mass >~ 10^10 GeV). These particles can be detected via nuclear recoils produced in elastic scatterings from nuclei. We estimate the observable rate of strongly interacting supermassive particles (simpzillas) in direct dark matter search experiments. The simpzilla energy loss in the Earth and in the experimental shields is taken into account. The most natural scenarios for simpzillas are ruled out based on recent EDELWEISS and CDMS results. The dark matter can be composed of superheavy particles only if these interact weakly with normal matter or if their mass is above 10^15 GeV.

astro-ph↗

arXiv2000

Hot and Cold Dark Matter Search with GENIUS

GENIUS is a proposal for a large volume detector to search for rare events. An array of 40-400 'naked' HPGe detectors will be operated in a tank filled with ultra-pure liquid nitrogen. After a description of performed technical studies of detector operation in liquid nitrogen and of Monte Carlo simulations of expected background components, the potential of GENIUS for detecting WIMP dark matter, the neutrinoless double beta decay in 76-Ge and low-energy solar neutrinos is discussed.

astro-ph↗

arXiv2000

Direct Detection of Nonbaryonic Dark Matter

Weakly Interacting Massive Particles (WIMPs) are leading candidates for the dominant part of the mass density of the Universe. Here we will review direct WIMP detection techniques by giving examples of currently running experiments, and present the status of the most promising future projects.

astro-ph↗

arXiv2000

GENIUS: the first real-time detector for solar pp-neutrinos?

The GENIUS project is a proposal for a large supersensitive Germanium detector system for WIMP and double beta decay searches with a much increased sensitivity relative to existing and other future experiments. In this paper, the possibility to detect low energy solar neutrinos with GENIUS in real-time through elastic neutrino-electron scattering is studied.

astro-ph↗