Search Our Scientific Publications & Authors

Sci Rep 2020 May 22;10(1):8525. Epub 2020 May 22.

Institute for Industrial, Radiophysical and Environmental Safety, Universitat Politècnica de València, Camino de Vera, s/n, 46022, València, Spain.

For several years, reports have been published about fluctuations in measured radioactive decay time-series and in some instances linked to astrophysical as well as classical environmental influences. Anomalous behaviors of radioactive decay measurement and measurement of capacitance inside and outside a modified Faraday cage were documented by our group in previous work. In the present report, we present an in-depth analysis of our measurement with regard to possible correlations with space weather, i. Read More

Eur Phys J C Part Fields 2020 17;80(5):431. Epub 2020 May 17.

2Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, C/Catedrático José Beltrán 2, 46980 Paterna, Valencia Spain.

We present a study on the possibility of searching for long-lived supersymmetric partners with the MoEDAL experiment at the LHC. MoEDAL is sensitive to highly ionising objects such as magnetic monopoles or massive (meta)stable electrically charged particles. We focus on prospects of directly detecting long-lived sleptons in a phenomenologically realistic model which involves an intermediate neutral long-lived particle in the decay chain. Read More

Phys Rev E 2020 Apr;101(4-1):043208

York Plasma Institute, Department of Physics, University of York, York YO10 5DD, England, United Kingdom.

The formation of high energy density matter occurs in inertial confinement fusion, astrophysical, and geophysical systems. In this context, it is important to couple as much energy as possible into a target while maintaining high density. A recent experimental campaign, using buried layer (or "sandwich" type) targets and the ultrahigh laser contrast Vulcan petawatt laser facility, resulted in 500 Mbar pressures in solid density plasmas (which corresponds to about 4. Read More

Phys Rev E 2020 Apr;101(4-1):043212

Institute of Astronomy and Space Physics, Ciudad Universitaria, Buenos Aires 1428, Argentina and Physics Department, University of Buenos Aires, Ciudad Universitaria, Buenos Aires 1428, Argentina.

We derive the exact relation for the energy transfer in three-dimensional compressible two-fluid plasma turbulence. In the long-time limit, we obtain an exact law which expresses the scale-to-scale average energy flux rate in terms of two point increments of the fluid variables of each species, electric and magnetic field and current density, and puts a strong constraint on the turbulent dynamics. The incompressible single fluid and two-fluid limits and the compressible single fluid limit are recovered under appropriate assumption. Read More

Phys Rev Lett 2020 May;124(17):171101

National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan.

The astrophysical reach of current and future ground-based gravitational-wave detectors is mostly limited by quantum noise, induced by vacuum fluctuations entering the detector output port. The replacement of this ordinary vacuum field with a squeezed vacuum field has proven to be an effective strategy to mitigate such quantum noise and it is currently used in advanced detectors. However, current squeezing cannot improve the noise across the whole spectrum because of the Heisenberg uncertainty principle: when shot noise at high frequencies is reduced, radiation pressure at low frequencies is increased. Read More

Proc Math Phys Eng Sci 2020 Apr 22;476(2236):20190867. Epub 2020 Apr 22.

Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA.

Magnetic reconnection has been intensively studied in fully ionized plasmas. However, plasmas are often partially ionized in astrophysical environments. The interactions between the neutral particles and ionized plasmas might strongly affect the reconnection mechanisms. Read More

Phys Chem Chem Phys 2020 May 12. Epub 2020 May 12.

Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, BP 48, Gif sur Yvette, France.

We present the photoionization dynamics of the C60 buckminsterfullerene from threshold up to 14.0 eV recorded with VUV synchrotron radiation at the DESIRS beamline at the SOLEIL synchrotron. The recorded data is obtained using a double-imaging photoelectron photoion coincidence spectrometer and is presented as a two-dimensional photoelectron matrix which contains a wealth of spectroscopic data. Read More

Astrobiology 2020 May;20(5):580-582

INAF-Astronomical Observatory of Trieste, Trieste, Italy.

Phys Rev Lett 2020 Apr;124(14):145101

Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France.

Black holes are known to launch powerful relativistic jets and emit highly variable gamma radiation. How these jets are loaded with plasma remains poorly understood. Spark gaps are thought to drive particle acceleration and pair creation in the black-hole magnetosphere. Read More

Nat Commun 2020 Apr 24;11(1):1989. Epub 2020 Apr 24.

CEA, DAM, DIF, 91297, Arpajon, France.

Superdense plasmas widely exist in planetary interiors and astrophysical objects such as brown-dwarf cores and white dwarfs. How atoms behave under such extreme-density conditions is not yet well understood, even in single-species plasmas. Here, we apply thermal density functional theory to investigate the radiation spectra of superdense iron-zinc plasma mixtures at mass densities of ρ = 250 to 2000 g cm and temperatures of kT = 50 to 100 eV, accessible by double-shell-target implosions. Read More

Phys Rev Lett 2020 Apr;124(13):131101

Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. Read More

ACS Nano 2020 Apr 21. Epub 2020 Apr 21.

Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea.

The astrophysical phenomenon of mimetic helical magnetic field ()-assisted self-assembly is herein introduced to build helical superstructures that display chiroptical properties. As a building block, magnetoplasmonic (MagPlas) Ag@FeO core-shell nanoparticles are used to guide plasmonic Ag nanoparticles onto a helical magnetic flux. The chirality of the assembled helical structures and tailored circular dichroism are successfully tuned in real time, and the handedness of the assembled structures is dynamically switched by the at the millisecond level, which is at least 6000-fold faster than other template-assisted methods. Read More

J Quant Spectrosc Radiat Transf 2020 Apr 13:107005. Epub 2020 Apr 13.

Crimean Astrophysical Observatory (CrAO RAS), Nauchnyj, 298409, Crimea.

Coronavirus virions have spherical shape surrounded by spike proteins. The coronavirus spike proteins are very effective molecular mechanisms, which provide the coronavirus entrance to the host cell. The number of these spikes is different; it dramatically depends on external conditions and determines the degree of danger of the virus. Read More

Mon Not R Astron Soc 2020 Apr 27;493(4):5273-5289. Epub 2020 Feb 27.

Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611, Australia.

We use the hydrodynamical simulation of our inner Galaxy presented in Armillotta et al. to study the gas distribution and kinematics within the Central Molecular Zone (CMZ). We use a resolution high enough to capture the gas emitting in dense molecular tracers such as NH and HCN, and simulate a time window of 50 Myr, long enough to capture phases during which the CMZ experiences both quiescent and intense star formation. Read More

Proc Natl Acad Sci U S A 2020 Apr 30;117(15):8398-8403. Epub 2020 Mar 30.

Department of Sociology, Princeton University, Princeton, NJ 08544;

How predictable are life trajectories? We investigated this question with a scientific mass collaboration using the common task method; 160 teams built predictive models for six life outcomes using data from the Fragile Families and Child Wellbeing Study, a high-quality birth cohort study. Despite using a rich dataset and applying machine-learning methods optimized for prediction, the best predictions were not very accurate and were only slightly better than those from a simple benchmark model. Within each outcome, prediction error was strongly associated with the family being predicted and weakly associated with the technique used to generate the prediction. Read More

Phys Rev Lett 2020 Mar;124(10):101302

Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China.

Chiral symmetry is maximally violated in weak interactions [1], and such microscopic asymmetries in the early Universe might leave observable imprints on astrophysical scales without violating the cosmological principle. In this Letter, we propose a helicity measurement to detect primordial chiral violation. We point out that observations of halo-galaxy angular momentum directions (spins), which are frozen in during the galaxy formation process, provide a fossil chiral observable. Read More

Phys Rev Lett 2020 Mar;124(10):105101

Astrophysical Institute, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.

We use the Low Frequency Array (LOFAR) to probe the dynamics of the stepping process of negatively charged plasma channels (negative leaders) in a lightning discharge. We observe that at each step of a leader, multiple pulses of vhf (30-80 MHz) radiation are emitted in short-duration bursts (<10  μs). This is evidence for streamer formation during corona flashes that occur with each leader step, which has not been observed before in natural lightning and it could help explain x-ray emission from lightning leaders, as x rays from laboratory leaders tend to be associated with corona flashes. Read More

Phys Rev Lett 2020 Mar;124(10):101102

Fermi National Accelerator Laboratory, P. O. Box 500, Batavia, Illinois 60510, USA.

In recent years, many γ-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe has been shown to be a promising tool. We report here the first identification of a cross-correlation signal between γ rays and the distribution of mass in the Universe probed by weak gravitational lensing. Read More

Phys Rev Lett 2020 Mar;124(9):095101

Southwest Research Institute, San Antonio, Texas 78228, USA.

Electrostatic solitary wave (ESW)-a Debye-scale structure in space plasmas-was believed to accelerate electrons. However, such a belief is still unverified in spacecraft observations, because the ESW usually moves fast in spacecraft frame and its interior has never been directly explored. Here, we report the first measurements of an ESW's interior, by the Magnetospheric Multiscale mission located in a magnetotail reconnection jet. Read More

Phys Rev E 2020 Feb;101(2-1):022903

Skolkovo Institute of Science and Technology, 121205, Moscow, Russia.

We investigate numerically and analytically size-polydisperse granular mixtures immersed into a molecular gas. We show that the equipartition of granular temperatures of particles of different sizes is established; however, the granular temperatures significantly differ from the temperature of the molecular gas. This result is surprising since, generally, the energy equipartition is strongly violated in driven granular mixtures. Read More

Phys Rev E 2020 Feb;101(2-1):023205

Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.

Currently there is considerable interest in creating scalable laboratory plasmas to study the mechanisms behind the formation and evolution of astrophysical phenomena such as Herbig-Haro objects and supernova remnants. Laboratory-scaled experiments can provide a well diagnosed and repeatable supplement to direct observations of these extraterrestrial objects if they meet similarity criteria demonstrating that the same physics govern both systems. Here, we present a study on the role of collision and cooling rates on shock formation using colliding jets from opposed conical wire arrays on a compact pulsed-power driver. Read More

Phys Rev E 2020 Feb;101(2-1):023211

Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey USA 08540.

A theoretically highly efficient mechanism, operating at high laser intensities and powers, is identified for spectral transferring huge laser energies to shorter ultraviolet and x-ray wavelengths. With megajoule laser energies currently available at near-optical wavelengths, this transfer would, in theory, enable megajoule x-ray lasers, a huge advance over the millijoules x-ray pulses produced now. In fact, enabling even kilojoule x-ray lasers would still be a fantastic advance, and a more likely achievable one, considering practical experimental inefficiencies. Read More

Phys Rev Lett 2020 Feb;124(8):081802

Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.

keV-scale gauge-singlet fermions, when allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early Universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting x-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. Read More

J Basic Microbiol 2020 Mar 12. Epub 2020 Mar 12.

Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai, India.

Genetic diversity studies are crucial for understanding the genetic structure and evolutionary dynamics of fungal species and communities. Fungal genomes are often reshaped by their repetitive components such as transposable elements. These elements are key players in genomic rearrangements and are ideal targets for genetic diversity and evolutionary studies. Read More

Sci Rep 2020 Mar 4;10(1):4336. Epub 2020 Mar 4.

Nasir al-Din al-Tusi Shamakhi Astrophysical Observatory Azerbaijan, AZ, 1000, Pirqulu, Azerbaijan.

This article has been retracted. Read More

Rev Sci Instrum 2020 Feb;91(2):023307

Institute for Modeling Plasma, Atmospheres, and Cosmic Dust, Boulder, Colorado 80303, USA.

Permanently polarized Polyvinylidene Fluoride (PVDF) films have been used on a variety of spacecraft as in situ dust detectors to measure the size and spatial distributions of micron and sub-micron dust particles. The detectors produce a short electric pulse when impacted by a hypervelocity dust particle. The pulse amplitude depends on the mass and relative speed of the dust grain. Read More

Phys Rev Lett 2020 Feb;124(6):062502

KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium.

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. Read More

Phys Rev Lett 2020 Feb;124(6):065101

Space Sciences Department, The Aerospace Corporation, El Segundo, California 90245, USA.

The first-order Fermi acceleration of electrons requires an injection of electrons into a mildly relativistic energy range. However, the mechanism of injection has remained a puzzle both in theory and observation. We present direct evidence for a novel stochastic shock drift acceleration theory for the injection obtained with Magnetospheric Multiscale observations at the Earth's bow shock. Read More

Astrobiology 2020 May 27;20(5):601-616. Epub 2020 Feb 27.

NASA Ames Research Center, MS 245-3, Moffett Field, California 94035.

Numerous laboratory studies of astrophysical ice analogues have shown that their exposure to ionizing radiation leads to the production of large numbers of new, more complex compounds, many of which are of astrobiological interest. We show here that the irradiation of astrophysical ice analogues containing HO, CHOH, CO, and NH yields quantities of hexamethylenetetramine-methanol (hereafter HMT-methanol; CNHO) that are easily detectible in the resulting organic residues. This molecule differs from simple HMT, which is known to be abundant in similar ice photolysis residues, by the replacement of a peripheral H atom with a CHOH group. Read More

Molecules 2020 Feb 22;25(4). Epub 2020 Feb 22.

Wellinq Medical, Van der Waals Park 22, 9351 VC Leek, The Netherlands.

This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. The computations of the OH spectra utilize line strength data that were developed previously and that are now communicated for the first time. The line strengths have been utilized extensively in interpretation of recorded molecular emission spectra and have been well-tested in laser-induced fluorescence applications for the purpose of temperature inferences from recorded data. Read More

Phys Rev Lett 2020 Feb;124(5):051103

III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen, Germany.

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. Read More

Phys Rev Lett 2020 Feb;124(5):055002

Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.

Tertiary modes in electrostatic drift-wave turbulence are localized near extrema of the zonal velocity U(x) with respect to the radial coordinate x. We argue that these modes can be described as quantum harmonic oscillators with complex frequencies, so their spectrum can be readily calculated. The corresponding growth rate γ_{TI} is derived within the modified Hasegawa-Wakatani model. Read More

Proc Math Phys Eng Sci 2020 Jan 8;476(2233):20190622. Epub 2020 Jan 8.

Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309, USA.

The magnetorotational instability (MRI) occurs when a weak magnetic field destabilizes a rotating, electrically conducting fluid with inwardly increasing angular velocity. The MRI is essential to astrophysical disc theory where the shear is typically Keplerian. Internal shear layers in stars may also be MRI-unstable, and they take a wide range of profiles, including near-critical. Read More

J Phys Chem A 2020 Mar 3;124(10):2001-2013. Epub 2020 Mar 3.

Department of Chemistry, University of California, Berkeley, California 94720, United States.

Nitrogen-containing ions and molecules in the gas phase have been detected in non-Earth environments such as dark molecular clouds and more recently in the atmosphere of Saturn's moon Titan. These molecules may serve as precursors to larger heterocyclic structures that provide the foundation of complex biological molecules. On Titan, molecules of / 66 have been detected by the Cassini mission, and species of the empirical formula CHN may contribute to this signature. Read More

Sci Adv 2020 02 5;6(6):eaax3419. Epub 2020 Feb 5.

MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge CB2 0QH, UK.

We advocate an integrative approach between laboratory experiments in prebiotic chemistry and geologic, geochemical, and astrophysical observations to help assemble a robust chemical pathway to life that can be reproduced in the laboratory. The cyanosulfidic chemistry scenario described here was developed by such an integrative iterative process. We discuss how it maps onto evolving planetary surface environments on early Earth and Mars and the value of comparative planetary evolution. Read More

Phys Rev Lett 2020 Jan;124(4):041102

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.

We seek to achieve the holy grail of Bayesian inference for gravitational-wave astronomy: using deep-learning techniques to instantly produce the posterior p(θ|D) for the source parameters θ, given the detector data D. To do so, we train a deep neural network to take as input a signal + noise dataset (drawn from the astrophysical source-parameter prior and the sampling distribution of detector noise), and to output a parametrized approximation of the corresponding posterior. We rely on a compact representation of the data based on reduced-order modeling, which we generate efficiently using a separate neural-network waveform interpolant [A. Read More

Sci Rep 2020 Feb 13;10(1):2507. Epub 2020 Feb 13.

Aston Institute of Photonic Technologies, Aston University, Birmingham, UK.

In hydrodynamics, vortex generation upon the transition from smooth laminar flows to turbulence is generally accompanied by increased dissipation. However, vortices in the plane can provide transport barriers and decrease losses, as it happens in numerous geophysical, astrophysical flows and in tokamaks. Photon interactions with matter can affect light transport in ways resembling fluid dynamics. Read More

Science 2020 02 13;367(6481). Epub 2020 Feb 13.

Lowell Observatory, Flagstaff, AZ 86001, USA.

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Read More

Astrophys J 2020 Jan;888(1)

Department of Mathematics and Statistics, University of Waikato, Hamilton, New Zealand.

The effects of turbulence in the very local interstellar medium (VLISM) have been proposed by Giacalone & Jokipii (2015) to be important in determining the structure of the () ribbon via particle trapping by magnetic mirroring. We further explore this effect by simulating the motion of charged particles in a turbulent magnetic field superposed on a large-scale mean field, which we consider to be either spatially-uniform or a draped field derived from a 3D MHD simulation. We find that the ribbon is not double-peaked, in contrast to Giacalone & Jokipii (2015). Read More

Chemphyschem 2020 03 19;21(6):525-530. Epub 2020 Feb 19.

Grupo de Espectroscopia Molecular (GEM), Edificio Quifima Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico Universidad de Valladolid, 47011, Valladolid, Spain.

Four conformers of the non-proteinogenic α-amino acid isovaline, vaporized by laser ablation, are characterized by Fourier-transform microwave techniques in a supersonic expansion. The comparison between the experimental rotational and N nuclear quadrupole coupling constants and the ab initio calculated ones provides conclusive evidence for the identification of the conformers. The most stable species is stabilized by an N-H⋅⋅⋅O =C intramolecular hydrogen bond and a cis-COOH interaction, whereas the higher-energy conformers exhibit an N⋅⋅⋅H-O intramolecular hydrogen bond and trans-COOH, as in other aliphatic amino acids. Read More

J Chem Phys 2020 Jan;152(4):041105

Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France.

The C carbon cluster is found in a large variety of environments including flames, electric discharges, and astrophysical media. Due to spin-selection rules, assessing a complete overview of the dense vibronic landscape of the C cation starting from the ground electronic state X Σg+1 of the neutral is not possible, especially since the C ground state is of X Σg-4 symmetry. In this work, a flow-tube reactor source is employed to generate the neutral C in a mixture of both the lowest singlet X Σg+1 and triplet a Π electronic states. Read More

Spectrochim Acta A Mol Biomol Spectrosc 2020 Apr 7;230:118011. Epub 2020 Jan 7.

Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700 084, India.

Electron attachment energy (eAE) and the dipole moment of the neutral molecules are related to the radiative electron attachment (REA) process, which is an important formation route of interstellar anions under various astrophysical environments. Electron attachment energies (eAEs) have been calculated for over 80 carbon chain neutral molecules; C, CX (X = N, O, S, H, Si, P), HCN using ab initio quantum chemical method. Dipole moments of these neutral species and those of their corresponding anions are also theoretically estimated. Read More

Science 2020 01;367(6476):415-418

Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.

Superluminous supernovae radiate up to 100 times more energy than normal supernovae. The origin of this energy and the nature of the stellar progenitors of these transients are poorly understood. We identify neutral iron lines in the spectrum of one such supernova, SN 2006gy, and show that they require a large mass of iron (≳0. Read More

J Phys Chem A 2020 Feb 23;124(5):1003-1010. Epub 2020 Jan 23.

Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière , F-69622 Villeurbanne , France.

The behavior of potential prebiotic species in space is of main concern in the chemistry at the origin of life. Their reactivity or stability in spatial conditions, under strong UV radiations or ion bombardments, remains an open question and needs wide investigations. As protons are by far the most abundant ions in space, we focus presently on proton-induced collisions on imidazole and 2-aminoimidazole evidenced as important prebiotic RNA intermediates. Read More

Proc Natl Acad Sci U S A 2020 01;117(2):799-801

Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544.

Phys Rev Lett 2019 Dec;123(24):241803

LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris 75252, France.

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Read More

Phys Rev Lett 2019 Dec;123(25):251101

Theoretical Physics Department, CERN, 1211 Geneva 23, Switzerland.

We derive the strongest constraint on the fraction of dark matter that can be composed of low mass primordial black holes by using the observation of the Galactic Center 511 keV γ-ray line. Primordial black holes of masses ≲10^{15}  kg will evaporate to produce e^{±} pairs. The positrons will lose energy in the Galactic Center, become nonrelativistic, then annihilate with the ambient electrons. Read More

Phys Rev Lett 2019 Dec;123(25):251801

LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris 75252, France.

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0. Read More

Nature 2020 01 6;577(7789):190-194. Epub 2020 Jan 6.

Department of Physics, McGill University, Montréal, Québec, Canada.

Fast radio bursts (FRBs) are brief, bright, extragalactic radio flashes. Their physical origin remains unknown, but dozens of possible models have been postulated. Some FRB sources exhibit repeat bursts. Read More

J Chem Phys 2019 Dec;151(24):244202

Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA.

The UF-CRDS (Uniform Flow-Cavity Ring Down Spectrometer) is a new setup coupling for the first time a pulsed uniform (Laval) flow with a continuous wave CRDS in the near infrared for spectroscopy and kinetics at low temperature. This high resolution and sensitive absorption spectrometer opens a new window into the phenomena occurring within UFs. The approach extends the detection range to new electronic and rovibrational transitions within Laval flows and offers the possibility to probe numerous species which have not been investigated yet. Read More