Results for "E. Aprile"

total 98005took 0.13s
Detection of partial polarization in Compton scattered photonsJun 18 2003It has been recently proposed (Boggs, Nucl. Instr. and Meth. A 503 (2003) 562), to use polarization of Compton scattered gamma-rays to improve the imaging performance of Compton telescopes. Building upon that work, we detected the aforementioned polarization ... More
Liquid Xenon Detectors for Particle Physics and AstrophysicsOct 26 2009This 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. We begin with a summary of the fundamental properties of liquid ... More
Performance of the Light Trigger System in the Liquid Xenon Gamma-Ray Telescope LXeGRITDec 18 2000LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber with charge and light readout. The energy and direction of an incident gamma-ray is reconstructed from the three-dimensional locations ... More
An Upgraded Data Acquisition System for the Balloon-Borne Liquid Xenon Gamma-Ray Telescope LXeGRITDec 12 2000Dec 14 2000LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber (LXe-TPC) with charge and light readout. The first balloon flights in 1997 revealed limitations of the trigger electronics and ... More
Detection of liquid xenon scintillation light with a Silicon PhotomultiplierJan 03 2005Jan 26 2005We have studied the feasibility of a silicon photomultiplier (SiPM) to detect liquid xenon (LXe) scintillation light. The SiPM was operated inside a small volume of pure LXe, at -95 degree Celsius, irradiated with an internal Am-241 alpha source. The ... More
Characterization of photomultiplier tubes with a realistic model through GPU-boosted simulationSep 30 2017Feb 25 2018The accurate characterization of a photomultiplier tube (PMT) is crucial in a wide-variety of applications. However, current methods do not give fully accurate representations of the response of a PMT, especially at very low light levels. In this work, ... More
Holographic Superconductors in a Cohesive PhaseJun 25 2012Sep 12 2012We consider a four-dimensional N=2 gauged supergravity coupled to matter fields. The model is obtained by a U(1) gauging of a charged hypermultiplet and therefore it is suitable for the study of holographic superconductivity. The potential has a topologically ... More
Measurement of light and charge yield of low-energy electronic recoils in liquid xenonNov 30 2016The dependence of the light and charge yield of liquid xenon on the applied electric field and recoil energy is important for dark matter detectors using liquid xenon time projections chambers. Few measurements have been made of this field dependence ... More
Observation of Anti-correlation between Scintillation and Ionization for MeV Gamma-Rays in Liquid XenonApr 09 2007A strong anti-correlation between ionization and scintillation signals produced by MeV gamma-rays in liquid xenon has been measured and used to improve the energy resolution by combining the two signals. The improvement is explained by reduced electron-ion ... More
Polaronic signature in the metallic phase of La0.7Ca0.3MnO3 films detected by scanning tunneling spectroscopyMar 19 2007Jul 23 2007In this work we map tunnel conductance curves with nanometric spatial resolution, tracking polaronic quasiparticle excitations when cooling across the insulator-to-metal transition in La0.7Ca0.3MnO3 films. In the insulating phase the spectral signature ... More
Fingerprint of dynamical charge/spin correlations in the tunneling spectra of colossal magnetoresistive manganitesJul 28 2009We present temperature-dependent scanning tunneling spectroscopy measurements on $La_{1-x}Ca_{x}MO_{3}$ ($x\sim0.33$) films with different degrees of biaxial strain. A depletion in normalized conductance around the Fermi level is observed both above and ... More
EGRET Observations of the Diffuse Gamma-Ray Emission in Orion: Analysis Through Cycle 6Feb 15 1999We present a study of the high-energy diffuse emission observed toward Orion by the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory. The total exposure by EGRET in this region has increased by more than a factor of ... More
Compton Imaging of MeV Gamma-Rays with the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)May 02 2008The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is the first realization of a liquid xenon time projection chamber for Compton imaging of MeV gamma-ray sources in astrophysics. By measuring the energy deposit and the three spatial coordinates of ... More
A Study of the LXeGRIT Detection Efficiency for MeV Gamma-Rays during the 2000 Balloon Flight CampaignFeb 09 2007Feb 09 2007LXeGRIT - Liquid Xenon Gamma-Ray Imaging Telescope - is the first prototype of a Compton telescope for \MeV \g-ray astrophysics based on a LXe time projection chamber. One of the most relevant figures of merit for a Compton telescope is the detection ... More
Gamma Ray Spectroscopy with Scintillation Light in Liquid XenonAug 03 2006Aug 04 2006Scintillation light from gamma ray irradiation in liquid xenon is detected by two Hamamatsu R9288 photomultiplier tubes (PMTs) immersed in the liquid. UV light reflector material, PTFE, is used to optimize the light collection efficiency. The detector ... More
Compton scattering sequence reconstruction algorithm for the liquid xenon gamma-ray imaging telescope (LXeGRIT)Dec 13 2000The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is a balloon born experiment sensitive to \g -rays in the energy band of 0.2-20 MeV. The main detector is a time projection chamber filled with high purity liquid xenon (LXeTPC), in which the three-dimensional ... More
The XENON Dark Matter ExperimentFeb 15 2005The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xenon nuclei. With a fiducial mass of 1000 kg of liquid xenon, a sufficiently low threshold of ... More
Quasi-Normal Modes from Non-Commutative Matrix DynamicsNov 02 2016We explore the connection between the process of relaxation in the BMN matrix model and the physics of black holes in AdS/CFT. Focusing on Dyson-fluid solutions of the matrix model, we perform numerical simulations of the real time dynamics of the system. ... More
Extended formulations from communication protocols in output-efficient timeNov 20 2018Deterministic protocols are well-known tools to obtain extended formulations, with many applications to polytopes arising in combinatorial optimization. Although constructive, those tools are not output-efficient, since the time needed to produce the ... More
Xenon Recirculation-Purification with a Heat ExchangerMar 04 2011Liquid-xenon based particle detectors have been dramatically growing in size during the last years, and are now exceeding the one-ton scale. The required high xenon purity is usually achieved by continuous recirculation of xenon gas through a high-temperature ... More
Extended formulations from communication protocols in output-efficient timeNov 20 2018Apr 08 2019Deterministic protocols are well-known tools to obtain extended formulations, with many applications to polytopes arising in combinatorial optimization. Although constructive, those tools are not output-efficient, since the time needed to produce the ... More
Scintillation Response of Liquid Xenon to Low Energy Nuclear RecoilsMar 29 2005Liquid Xenon (LXe) is expected to be an excellent target and detector medium to search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Knowledge of LXe ionization and scintillation response to low energy nuclear recoils expected ... More
A Simple Holographic Model of a Charged LatticeJun 27 2014Jul 15 2014We use holography to compute the conductivity in an inhomogeneous charged scalar background. We work in the probe limit of the four-dimensional Einstein-Maxwell theory coupled to a charged scalar. The background has zero charge density and is constructed ... More
$\mathcal{N}=2$ supersymmetric field theories on 3-manifolds with A-type boundariesApr 06 2016General half-BPS A-type boundary conditions are formulated for N=2 supersymmetric field theories on compact 3-manifolds with boundary. We observe that under suitable conditions manifolds of the real A-type admitting two complex supersymmetries (related ... More
Large-N transitions of the connectivity indexOct 28 2014Jan 15 2015The connectivity index, defined as the number of decoupled components of a separable quantum system, can change under deformations of the Hamiltonian or during the dynamical change of the system under renormalization group flow. Such changes signal a ... More
Multiple blow-up solutions for the Liouville equation with singular dataOct 23 2012We study the existence of solutions with multiple concentration to the following boundary value problem $$-\Delta u=\e^2 e^u-4\pi \sum_{p\in Z}\alpha_p \delta_{p}\;\hbox{in} \Omega,\quad u=0 \;\hbox{on}\partial \Omega,$$ where $\Omega$ is a smooth and ... More
Performance of a Large Area Avalanche Photodiode in a Liquid Xenon Ionization and Scintillation ChamberFeb 14 2005Scintillation light produced in liquid xenon (LXe) by alpha particles, electrons and gamma-rays was detected with a large area avalanche photodiode (LAAPD) immersed in the liquid. The alpha scintillation yield was measured as a function of applied electric ... More
Strong-coupling analysis of scanning tunneling spectra in Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+δ}$Mar 11 2013Aug 01 2013We study a series of spectra measured in the superconducting state of optimally-doped Bi-2223 by scanning tunneling spectroscopy. Each spectrum, as well as the average of spectra presenting the same gap, is fitted using a strong-coupling model taking ... More
New Measurement of the Relative Scintillation Efficiency of Xenon Nuclear Recoils Below 10 keVOct 01 2008May 16 2010Liquid xenon is an important detection medium in direct dark matter experiments, which search for low-energy nuclear recoils produced by the elastic scattering of WIMPs with quarks. The two existing measurements of the relative scintillation efficiency ... More
Positive and sign-changing clusters around saddle points of the potential for nonlinear elliptic problemsJul 03 2009We study the existence of positive and sign-changing multipeak solutions for the stationary Nonlinear Schroedinger Equation. Here no symmetry on $V$ is assumed. It is known that this equation has positive multipeak solutions with all peaks approaching ... More
Spectroscopy and Imaging Performance of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)Dec 13 2000LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic \g-rays in the energy band of 0.2-20 MeV. The detector, with 400 cm$^2$ area and 7 cm drift gap, is filled with high purity LXe. Both ... More
Preliminary Results from the 1999 Balloon Flight of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)Dec 19 2000LXeGRIT is a balloon-borne Compton telescope employing a large volume liquid xenon time projection chamber (LXeTPC) as the central gamma-ray detector. It is designed to image gamma rays in the energy range of 200 keV to 20 MeV, with an angular resolution ... More
On the Background Rate in the LXeGRIT Instrument during the 2000 Balloon FlightNov 27 2002Dec 04 2002LXeGRIT is the first prototype of a novel Compton telescope for MeV gamma-ray astrophysics based on a Liquid Xenon Time Projection Chamber (LXeTPC), sensitive in the energy band of 0.15-10 MeV. In this homogeneous, 3D position sensitive detector, gamma ... More
Simultaneous Measurement of Ionization and Scintillation from Nuclear Recoils in Liquid Xenon as Target for a Dark Matter ExperimentJan 24 2006We report the first measurements of the absolute ionization yield of nuclear recoils in liquid xenon, as a function of energy and electric-field. Independent experiments were carried out with two dual-phase time projection chamber prototypes, developed ... More
New Measurement of the Scintillation Efficiency of Low-Energy Nuclear Recoils in Liquid XenonApr 13 2011Particle detectors that use liquid xenon (LXe) as detection medium are among the leading technologies in the search for dark matter weakly interacting massive particles (WIMPs). A key enabling element has been the low-energy detection threshold for recoiling ... More
The LXeGRIT Compton Telescope Prototype: Current Status and Future ProspectsNov 30 2002Dec 04 2002LXeGRIT is the first prototype of a novel concept of Compton telescope, based on the complete 3-dimensional reconstruction of the sequence of interactions of individual gamma rays in one position sensitive detector. This balloon-borne telescope consists ... More
Solutions with multiple alternate sign peaks along a boundary geodesic to a semilinear Dirichlet problemOct 30 2012We study the existence of sign-changing multiple interior spike solutions for the following Dirichlet problem {equation*}\e^2\Delta v-v+f(v)=0\hbox{in}\Omega,\quad v=0 \hbox{on}\partial \Omega,{equation*} where $\Omega $ is a smooth and bounded domain ... More
Equilibria of point-vortices on closed surfacesFeb 19 2015We discuss the existence of equilibrium configurations for the Hamiltonian point-vortex model on a closed surface $\Sigma$. The topological properties of $\Sigma$ determine the occurrence of three distinct situations, corresponding to $\mathbb{S}^2$, ... More
Models of Holographic superconductivityDec 02 2009Jan 21 2010We construct general models for holographic superconductivity parametrized by three couplings which are functions of a real scalar field and show that under general assumptions they describe superconducting phase transitions. While some features are universal ... More
Imaging the essential role of spin-fluctuations in high-Tc superconductivitySep 02 2009We have used scanning tunneling spectroscopy to investigate short-length electronic correlations in three-layer Bi2Sr2Ca2Cu3O(10+d) (Bi-2223). We show that the superconducting gap and the energy Omega_dip, defined as the difference between the dip minimum ... More
Gator: a low-background counting facility at the Gran Sasso Underground LaboratoryMar 10 2011Jan 10 2012A low-background germanium spectrometer has been installed and is being operated in an ultra-low background shield (the Gator facility) at the Gran Sasso underground laboratory in Italy (LNGS). With an integrated rate of ~0.16 events/min in the energy ... More
Measurements of proportional scintillation and electron multiplication in liquid xenon using thin wiresAug 26 2014Nov 10 2014Proportional scintillation in liquid xenon has a promising application in the field of direct dark matter detection, potentially allowing for simpler, more sensitive detectors. However, knowledge of the basic properties of the phenomenon as well as guidelines ... More
Deep Underground Science and Engineering Lab: S1 Dark Matter Working GroupMay 30 2006Apr 23 2007A study of the current status of WIMP dark matter searches has been made in the context of scientific and technical planning for a Deep Underground Science and Engineering Laboratory (DUSEL) in the U.S. The table of contents follows: 1. Overview 2. WIMP ... More
The XENON1T Dark Matter Search ExperimentJun 27 2012The worldwide race towards direct dark matter detection in the form of Weakly Interacting Massive Particles (WIMPs) has been dramatically accelerated by the remarkable progress and evolution of liquid xenon time projection chambers (LXeTPCs). With a realistic ... More
Measurement of the Scintillation Yield of Low-Energy Electrons in Liquid XenonSep 17 2012We have measured the energy dependence of the liquid xenon (LXe) scintillation yield of electrons with energy between 2.1 and 120.2keV, using the Compton coincidence technique. A LXe scintillation detector with a very high light detection efficiency was ... More
Flipping the head of T[SU(N)]: mirror symmetry, spectral duality and monopolesDec 19 2018We consider T[SU(N)] and its mirror, and we argue that there are two more dual frames, which are obtained by adding flipping fields for the moment maps on the Higgs and Coulomb branch. Turning on a monopole deformation in T[SU(N)], and following its effect ... More
Simultaneous measurement of the light and charge response of liquid xenon to low-energy nuclear recoils at multiple electric fieldsSep 06 2018Nov 05 2018Dual-phase liquid xenon (LXe) detectors lead the direct search for particle dark matter. Understanding the signal production process of nuclear recoils in LXe is essential for the interpretation of LXe based dark matter searches. Up to now, only two experiments ... More
XENON: a 1 tonne Liquid Xenon Experiment for a Sensitive Dark Matter SearchJul 31 2002XENON is a novel liquid xenon experiment concept for a sensitive dark matter search using a 1-tonne active target, distributed in an array of ten independent time projection chambers. The design relies on the simultaneous detection of ionization and scintillation ... More
Holographic Superconductors from Gauged SupergravityApr 22 2011Nov 17 2011We consider minimal setups arising from different truncations of N=8 five-dimensional SO(6) gauged supergravity to study phase transitions involving spontaneous breaking of any of the U(1) symmetries in U(1)xU(1)xU(1)in SO(6). These truncations only keep ... More
A continuum of solutions for the SU(3) Toda System exhibiting partial blow-upJul 31 2014In this paper we consider the so-called Toda System in planar domains under Dirichlet boundary condition. We show the existence of continua of solutions for which one component is blowing up at a certain number of points. The proofs use singular perturbation ... More
Asymmetric blow-up for the SU(3) Toda SystemNov 13 2014We consider the so-called Toda system in a smooth planar domain under homogeneous Dirichlet boundary conditions. We prove the existence of a continuum of solutions for which both components blow-up at the same point. This blow-up behavior is asymmetric, ... More
On 2-level polytopes arising in combinatorial settingsFeb 10 2017Dec 14 20172-level polytopes naturally appear in several areas of pure and applied mathematics, including combinatorial optimization, polyhedral combinatorics, communication complexity, and statistics. In this paper, we present a study of some 2-level polytopes ... More
On the profile of sign changing solutions of an almost critical problem in the ballAug 29 2012We study the existence and the profile of sign-changing solutions to the slightly subcritical problem $$ -\De u=|u|^{2^*-2-\eps}u \hbox{in} \cB, \quad u=0 \hbox{on}\partial \cB, $$ where $\cB$ is the unit ball in $\rr^N$, $N\geq 3$, $2^*=\frac{2N}{N-2}$ ... More
Multi-bubble nodal solutions for slightly subcritical elliptic problems in domains with symmetriesAug 29 2012We study the existence of sign-changing solutions with multiple bubbles to the slightly subcritical problem $$-\Delta u=|u|^{2^*-2-\e}u \hbox{in}\Omega, \quad u=0 \hbox{on}\partial \Omega,$$ where $\Omega$ is a smooth bounded domain in $\R^N$, $N\geq ... More
Measurement of the Quantum Efficiency of Hamamatsu R8520 Photomultipliers at Liquid Xenon TemperatureJul 23 2012Vacuum ultraviolet light sensitive photomultiplier tubes directly coupled to liquid xenon are being used to efficiently detect the 178 nm scintillation light in a variety of liquid xenon based particle detectors. Good knowledge of the performance of these ... More
Limits on the release of Rb isotopes from a zeolite based 83mKr calibration source for the XENON projectSep 20 2011Oct 06 2011The isomer 83mKr with its half-life of 1.83 h is an ideal calibration source for a liquid noble gas dark matter experiment like the XENON project. However, the risk of contamination of the detector with traces of the much longer lived mother isotop 83Rb ... More
Secondary Scintillation Yield in Pure XenonFeb 16 2007The xenon secondary scintillation yield was studied as a function of the electric field in the scintillation region, in a gas proportional scintillation counter operated at room temperature. A large area avalanche photodiode was used for the readout of ... More
The XENON Dark Matter Search ExperimentJul 28 2004The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xe nuclei. A fiducial mass of 1000 kg, distributed in ten independent liquid xenon time projection ... More
Dark Matter Results from 225 Live Days of XENON100 DataJul 25 2012Mar 20 2013We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) for 13 months during 2011 and 2012. XENON100 features an ultra-low electromagnetic background of (5.3 \pm 0.6) \times ... More
Status and Sensitivity Projections for the XENON100 Dark Matter ExperimentFeb 24 2009The 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 ... More
Prescribed Gauss curvature problem on singular surfacesDec 12 2016Jan 19 2017We study the existence of at least one conformal metric of prescribed Gaussian curvature on a closed surface $\Sigma$ admitting conical singularities of orders $\alpha_i$'s at points $p_i$'s. In particular, we are concerned with the case where the prescribed ... More
p-wave Holographic Superconductors and five-dimensional gauged SupergravityNov 09 2010Dec 15 2010We explore five-dimensional ${\cal N}=4$ $SU(2)\times U(1)$ and ${\cal N}=8$ SO(6) gauged supergravities as frameworks for condensed matter applications. These theories contain charged (dilatonic) black holes and 2-forms which have non-trivial quantum ... More
Extension complexity of stable set polytopes of bipartite graphsFeb 28 2017Jun 05 2017The extension complexity $\mathsf{xc}(P)$ of a polytope $P$ is the minimum number of facets of a polytope that affinely projects to $P$. Let $G$ be a bipartite graph with $n$ vertices, $m$ edges, and no isolated vertices. Let $\mathsf{STAB}(G)$ be the ... More
Phenomenological Models of Holographic Superconductors and Hall currentsMar 23 2010Jun 01 2010We study general models of holographic superconductivity parametrized by four arbitrary functions of a neutral scalar field of the bulk theory. The models can accommodate several features of real superconductors, like arbitrary critical temperatures and ... More
Constraining the spin-dependent WIMP-nucleon cross sections with XENON1TFeb 08 2019We report the first experimental results on spin-dependent elastic WIMP-nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full tonne-year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only ... More
3D Position Sensitive XeTPC for Dark Matter SearchSep 26 2006The technique to realize 3D position sensitivity in a two-phase xenon time projection chamber (XeTPC) for dark matter search is described. Results from a prototype detector (XENON3) are presented.
Likelihood Approach to the First Dark Matter Results from XENON100Mar 01 2011Sep 07 2011Many experiments that aim at the direct detection of Dark Matter are able to distinguish a dominant background from the expected feeble signals, based on some measured discrimination parameter. We develop a statistical model for such experiments using ... More
Scanning tunneling spectroscopy of high-temperature superconductorsOct 24 2006Tunneling spectroscopy played a central role in the experimental verification of the microscopic theory of superconductivity in the classical superconductors. Initial attempts to apply the same approach to high-temperature superconductors were hampered ... More
Local quasiparticle density of states of superconducting SmFeAsO$1-x$F$x$ single crystals: Evidence for spin-mediated pairingAug 11 2010We probe the local quasiparticles density-of-states in micron-sized SmFeAsO$_{1-x}$F$_{x}$ single-crystals by means of Scanning Tunnelling Spectroscopy. Spectral features resemble those of cuprates, particularly a dip-hump-like structure developed at ... More
Material screening and selection for XENON100Mar 30 2011Jun 22 2011Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This Dark Matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra ... More
Study of the electromagnetic background in the XENON100 experimentJan 20 2011Feb 21 2013The XENON100 experiment, located at the Laboratori Nazionali del Gran Sasso (LNGS), aims to directly detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off xenon nuclei. We present a comprehensive ... More
First Dark Matter Results from the XENON100 ExperimentMay 03 2010Mar 01 2011The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, ... More
The XENON100 Dark Matter ExperimentJul 11 2011Feb 08 2012The XENON100 dark matter experiment uses liquid xenon (LXe) in a time projection chamber (TPC) to search for Xe nuclear recoils resulting from the scattering of dark matter Weakly Interacting Massive Particles (WIMPs). In this paper we present a detailed ... More
Shape and Motion of Vortex Cores in Bi_2Sr_2CaCu_2O_{8+δ}Feb 10 2000Aug 07 2000We present a detailed study on the behaviour of vortex cores in Bi_2Sr_2CaCu_2O_{8+\delta} using scanning tunneling spectroscopy. The very irregular distribution and shape of the vortex cores imply a strong pinning of the vortices by defects and inhomogeneities. ... More
First direct observation of the Van Hove singularity in the tunneling spectra of cupratesMar 04 2011In two-dimensional lattices the electronic levels are unevenly spaced, and the density of states (DOS) displays a logarithmic divergence known as the Van Hove singularity (VHS). This is the case in particular for the layered cuprate superconductors. The ... More
Unexpectedly wide reversible vortex region in $β$-pyrochlore RbOs$_{2}$O$_{6}$Jun 20 2008Aug 26 2008We study the extent of the reversible region in the vortex phase diagram of recently available RbOs$_2$O$_6$ single crystals \cite{Rogacki08a} by means of bulk magnetization measurements. We found that the irreversible magnetic response sets in at a field ... More
An atom trap trace analysis system for measuring krypton contamination in xenon dark matter detectorsMay 28 2013Sep 27 2013We have developed an atom trap trace analysis (ATTA) system to measure Kr in Xe at the part per trillion (ppt) level, a prerequisite for the sensitivity achievable with liquid xenon dark matter detectors beyond the current generation. Since Ar and Kr ... More
Superconductors for superstrings on AdS_5 x T^{1,1}May 09 2012We construct a one-parameter family of five-dimensional N=2 supergravity Lagrangians with an SU(2,1) / U(2) hypermultiplet. For certain values of the parameter, these are argued to describe the dynamics of scalar modes of superstrings on AdS_5 x T^{1,1}, ... More
Measurement of neutrino oscillations by means of a high density detector on the atmospheric neutrino beamJul 16 1999A high-density calorimeter, consisting of magnetized iron planes interleaved by RPCs, as tracking and timing devices, is a good candidate for a next generation experiment on atmospheric neutrinos. With 34 kt of mass and in four years of data taking, this ... More
The Advanced Compton Telescope MissionAug 24 2006The Advanced Compton Telescope (ACT), the next major step in gamma-ray astronomy, will probe the fires where chemical elements are formed by enabling high-resolution spectroscopy of nuclear emission from supernova explosions. During the past two years, ... More
Design and Performance of the XENON10 Dark Matter ExperimentJan 16 2010XENON10 is the first two-phase xenon time projection chamber (TPC) developed within the XENON dark matter search program. The TPC, with an active liquid xenon (LXe) mass of about 14 kg, was installed at the Gran Sasso underground laboratory (LNGS) in ... More
Limits on spin-dependent WIMP-nucleon cross-sections from the XENON10 experimentMay 19 2008Sep 10 2008XENON10 is an experiment to directly detect weakly interacting massive particle (WIMPs), which may comprise the bulk of the non-baryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129-Xe and 131-Xe ... More
The scintillation and ionization yield of liquid xenon for nuclear recoilsJul 03 2008Dec 31 2008XENON10 is an experiment designed to directly detect particle dark matter. It is a dual phase (liquid/gas) xenon time-projection chamber with 3D position imaging. Particle interactions generate a primary scintillation signal (S1) and ionization signal ... More
Constraints on inelastic dark matter from XENON10Oct 19 2009Nov 30 2010It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results ... More
A search for light dark matter in XENON10 dataApr 15 2011May 07 2013We report results of a search for light (<10 GeV) particle dark matter with the XENON10 detector. The event trigger was sensitive to a single electron, with the analysis threshold of 5 electrons corresponding to 1.4 keV nuclear recoil energy. Considering ... More
Lowering the low-energy threshold of xenon detectorsNov 30 2010We show that the energy threshold for nuclear recoils in the XENON10 dark matter search data can be lowered to ~1 keV, by using only the ionization signal. In other words, we make no requirement that a valid event contain a primary scintillation signal. ... More
First Results from the XENON10 Dark Matter Experiment at the Gran Sasso National LaboratoryMay 31 2007Dec 03 2007The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber (XeTPC) to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and ... More
Revisiting the vortex-core tunnelling spectroscopy in YBa$_2$Cu$_3$O$_{7-δ}$Jul 24 2015Apr 01 2016The observation by scanning tunnelling spectroscopy (STS) of Abrikosov vortex cores in the high-temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$ (Y123) has revealed a robust pair of electron-hole symmetric states at finite subgap energy. Their interpretation ... More
Performance of a cryogenic system prototype for the XENON1T DetectorAug 09 2012Aug 29 2012We have developed an efficient cryogenic system with heat exchange and associated gas purification system, as a prototype for the XENON1T experiment. The XENON1T detector will use about 3 ton of liquid xenon (LXe) at a temperature of 175K as target and ... More
Implications on Inelastic Dark Matter from 100 Live Days of XENON100 DataApr 15 2011Sep 09 2011The XENON100 experiment has recently completed a dark matter run with 100.9 live-days of data, taken from January to June 2010. Events in a 48kg fiducial volume in the energy range between 8.4 and 44.6 keVnr have been analyzed. A total of three events ... More
Dark Matter Results from 100 Live Days of XENON100 DataApr 13 2011Sep 07 2011We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction ... More
A Subjective Approach to Quantum ProbabilityMar 06 2005A likelihood order is defined over linear subspaces of a finite dimensional Hilbert space. It is shown that such an order that satisfies some plausible axioms can be represented by a quantum probability in two cases: pure state and uniform measure.
Gauge Invariant Classes of Feynman Diagrams and Applications for CalculationsJan 24 2001In theories like SM or MSSM with a complex gauge group structure the complete set of Feynman diagrams contributed to a particular physics process can be splited to exact gauge invariant subsets. Arguments and examples given in the review demonstrate that ... More
Off shell pi N amplitude and the p p->p p pi0 reactionMar 21 1995We have used a conventional model for the $pp \rightarrow pp \pi^{0}$ reaction consisting of the Born term plus the $s$-wave rescattering term. As a novelty we have introduced the off shell dependence of the $\pi N$ $s$-wave isoscalar amplitude. This ... More
A question in the axiomatic approach to Quantum MechanicsJul 09 2004The classical Hilbert space formulation of the axioms of Quantum Mechanics appears to leave open the question whether the Hermitian operators which are associated with the observables of a finite non-relativistic quantum system are uniquely determined. ... More
Tame division algebras of prime period over function fields of $p$-adic curvesMar 09 2010Mar 30 2012Let F be a field of transcendence degree one over a p-adic field, and let l be a prime not equal to p. Results of Merkurjev and Saltman show that H^2(F,\mu_l) is generated by Z/l-cyclic classes. We prove the "Z/l-length" in H^2(F,\mu_l) equals the l-Brauer ... More
Topologies and all that -- A TutorialMar 03 2015This is a brief introduction to the basic concepts of topology. It includes the basic constructions, discusses separation properties, metric and pseudometric spaces, and gives some applications arising from the use of topology in computing.
Observation of a two-dimensional electron gas at the surface of annealed SrTiO3 single crystals by scanning tunneling spectroscopyFeb 03 2012Scanning tunneling spectroscopy suggests the formation of a two dimensional electron gas (2DEG) on the TiO2 terminated surface of undoped SrTiO3 single crystals annealed at temperature lower than 400 {\deg}C in ultra high vacuum conditions. Low energy ... More
Mesonic and Binding Contributions to the Nuclear Drell-Yan ProcessDec 01 1997We have evaluated the Drell-Yan cross section in nuclei paying special attention to the meson cloud contribution from pion and rho-meson, for which an accurate calculation using the meson nuclear spectral functions is used. Similarly, the nucleonic contribution ... More
On non-linear superfield versions of the vector-tensor multipletNov 06 1997Jan 30 1998We propose a harmonic superspace description of the non-linear vector-tensor N=2 multiplet. We show that there exist two inequivalent version: the old one in which one of the vectors is the field-strength of a gauge two-form, and a new one in which this ... More