Showing papers in "Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields in 2017"
TL;DR: The first direct detection of a gravitational wave signal from a binary black hole merger was reported in this paper, with the properties of the source and the implications in terms of astrophysics and fundamental physics.
Abstract: This article provides an overview of the first direct detection of a gravitational wave signal —GW150914— from a binary black hole merger, of the properties of the source and the implications in terms of astrophysics and fundamental physics.
6 citations
TL;DR: In this paper, a new approach to identify fragments using computer simulations of relativistic heavy ion collisions is presented, based on the simulated annealing technique and can be applied to n-body transport models such as quantum molecular dynamics.
Abstract: We present a new approach to identify fragments using computer simulations of relativistic heavy ion collisions. It is based on the simulated annealing technique and can be applied to n-body transport models such as quantum molecular dynamics. This new approach is able to predict isotope yields as well as hypernucleus production. In order to illustrate its predicting power, we confront this new method with experimental data and show the sensitivity to the parameters which govern cluster formation.
5 citations
TL;DR: In this paper, the dissolution of strongly interacting matter with increasing density and temperature can be modeled with different approaches, in particular a geometric excluded-volume mechanism or a more microscopic model with medium dependent mass shift.
Abstract: — The dissolution of clusters in strongly interacting matter with increasing density and temperature can be modeled with different approaches, in particular a geometric excluded-volume mechanism or a more microscopic model with medium dependent mass shift. The predictions of the chemical composition and of thermodynamic properties are compared for two such equation-of-state models that realize these approaches but use the same model for the interaction of nucleons, i.e., a relativistic mean-field model with density-dependent nucleon-meson couplings. The main differences are found for heavy nuclei in the chemical composition of neutron star matter, but the thermodynamic properties of the two models are quite similar.
3 citations
TL;DR: In this paper, the main issues regarding the search of continuous gravitational waves in the data of current interferometric detectors and some recently published results are discussed, as well as the recent published results.
Abstract: — The detection of continuous gravitational waves is among the main targets of the LIGO and Virgo detectors. Such kind of signals, emitted e.g. by spinning neutron stars asymmetric with respect to the rotation axis, are very weak and their search poses challenging data analysis problems. In this review I will discuss the main issues regarding the search of continuous gravitational waves in the data of current interferometric detectors and some recently published results.
3 citations
TL;DR: In this article, the past and current LIGO and Virgo Collaboration electromagnetic follow-up program for transient sources of gravitational waves is described, as well as the expected scenarios for future science runs.
Abstract: — The detection of the electromagnetic counterparts of gravitational wave sources enables to gain a wealth of complementary information, ultimately providing a more complete phenomenological picture of a number of astrophysical source classes. This paper reports on the past and current LIGO and Virgo Collaboration (LVC) electromagnetic follow-up program for transient sources of gravitational waves. The program improvements between different science runs are highlighted, as well as the expected scenarios for future science runs.
2 citations
TL;DR: The Pierre Auger Observatory is the largest observatory in the world for the detection of ultra-high-energy cosmic rays as discussed by the authors, and it was decided to extend the operation of the Observatory up to 2024 and to enhance its capability in identifying the mass of the primary cosmic rays.
Abstract: — The Pierre Auger Observatory is the largest observatory in the world for the detection of ultrahigh-energy cosmic rays. The Auger Collaboration started collecting data in 2004, and, so far, results have led to many significant discoveries in this field but also to puzzling observations. To answer all the key questions that are still open it was decided to extend the operation of the Observatory up to 2024 and to enhance its capability in identifying the mass of the primary cosmic rays. Motivations for the upgrade will be described together with some hardware characteristics of the project.
2 citations
TL;DR: In this paper, the relation between the study of the fluxes of cosmic rays, gamma rays and neutrinos, and the connection of these observations with the newly born field of gravitational wave astronomy is discussed.
Abstract: This paper discusses the relation between the study of the fluxes of cosmic rays, gamma rays and neutrinos, and the connection of these observations with the newly born field of gravitational wave astronomy.
2 citations
University of Naples Federico II1, Moscow State University2, Kobe University3, University of Bern4, Middle East Technical University5, Joint Institute for Nuclear Research6, University of Salerno7, University of Padua8, University of Hamburg9, University of Bari10, University of Savoy11, University of Strasbourg12, University of Bologna13, Toho University14, Technion – Israel Institute of Technology15, Nagoya University16, Imperial College London17, Ankara University18, Gyeongsang National University19, Aichi University of Education20, CERN21, Nihon University22, University of Liverpool23, Sapienza University of Rome24, University of Milan25, Université libre de Bruxelles26
TL;DR: The OPERA experiment reached its main goal by proving the appearance of v τ in the CNGS v μ beam as discussed by the authors, where five candidates were detected with a S/B ratio of ∼ 10, allowing to reject the null hypothesis at 5.1σ.
Abstract: The OPERA experiment reached its main goal by proving the appearance of v τ in the CNGS v μ beam. Five v τ candidates were detected with a S/B ratio of ∼ 10, allowing to reject the null hypothesis at 5.1σ. The search has been extended by loosening the selection criteria in order to improve the statistical uncertainty. One of the v τ candidates selected with the new strategy shows a double vertex topology and, after a dedicated multivariate analysis, is compatible with being a v Tτ interaction with charm production. Based on the enlarged data sample the estimation of Δm 22 3 in appearance mode is being performed. The search for v e interactions has been extended over the full data set with a more than twofold increase in statistics: data are compatible with the non-oscillation hypothesis in the three-flavour mixing model. The implications of the electron neutrino sample in the framework of the 3+1 sterile mode will lead to exclusion limits on sin 2 2θ μe . Finally, the analysis of the annual modulation of cosmic muons is introduced.
2 citations
TL;DR: DarkSide-50 as discussed by the authors is a two-phase time projection chamber (TPC) filled with ultra-pure liquid argon, which is used to detect rare nuclear recoils possibly induced by hypothetical dark matter particles.
Abstract: DarkSide is a dark matter direct search experiment at Laboratori Nazionali del Gran Sasso (LNGS). DarkSide is based on the detection of rare nuclear recoils possibly induced by hypothetical dark matter particles, which are supposed to be neutral, massive (m > 10 GeV) and weakly interactive (WIMP). The dark matter detector is a two-phase time projection chamber (TPC) filled with ultra-pure liquid argon. The TPC is placed inside a muon and a neutron active vetoes to suppress the background. Using argon as active target has many advantages, the key features are the strong discriminant power between nuclear and electron recoils, the spatial reconstruction and easy scalability to multi-tons size. At the moment DarkSide-50 is filled with ultra-pure argon, extracted from underground sources, and from April 2015 it is taking data in its final configuration. When combined with the preceding search with an atmospheric argon target, it is possible to set a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 2.0×10−44 cm2 for a WIMP mass of 100 GeV/c2. The next phase of the experiment, DarkSide-20k, will be the construction of a new detector with an active mass of ∼ 20 tons.
1 citations
TL;DR: In this article, the results of the CDF and D0 detectors for Run II are presented based on an integrated luminosity of ∼ 10 fb−1 for 1.96 TeV pp collisions, representing the full Tevatron Run II data sets.
Abstract: The CDF [1] and D0 [2] detectors for Run II are illustrated below. The results presented here are based on an integrated luminosity of ∼ 10 fb−1 for 1.96 TeV pp collisions, representing the full Tevatron Run II data sets which were taken from 20012011. Both the CDF and the D0 detectors have solenoidal magnetic fields of 1.4 Tesla and 1.9 Tesla respectively, and excellent lepton coverage, detection, identification, and
1 citations
TL;DR: In this paper, the authors review the status of such searches and give prospects for future observations with the Cherenkov Telescope Array (CTA) and give a review of the current state of the art.
Abstract: — Cosmological observations indicate that approximately 27% of the energy density of the universe is in the form of dark matter which is non-baryonic. The nature of dark matter is an open question in modern physics. A well-motivated candidate constituent is a weakly interacting massive particle (WIMP) with mass in the range between O(10)GeV and O(100)TeV. The annihilation radiation from such particles can be searched for with imaging atmospheric Cherenkov telescopes (IACTs) such as the planned Cherenkov Telescope Array. Dwarf spheroidal galaxies (dSphs) of the Milky Way are among the most promising targets since these are dynamically dominated by dark matter and have no intrinsic (astrophysical) gammaray emission. In this contribution we will review the status of such searches and give prospects for future observations with the Cherenkov Telescope Array.
TL;DR: In this paper, the authors show that positrons are a rare component of the Cosmic Ray (CR), representing only 1% and 0.1% of the total CR flux, dominated by protons (90%) and alpha particle (8%).
Abstract: Electrons (e−) and positrons (e) are a rare component of the Cosmic Ray (CR), representing only 1% and 0.1%, respectively, of the total CR flux, dominated by protons (90%) and alpha particle (8%). Due to their low mass, e± suffer higher energy losses than those of hadronic CR, during the interaction with the InterStellar Medium (ISM). In the most common astrophysical models, e− are mainly of primary origin, produced and accelerated in astrophysical sources, whereas e are mostly produced in the interactions of protons and nuclei with the ISM, e flux is expected to extinguish more rapidly with increasing energy with respect to that of e−. Naturally rare, e are a good channel to study deviation from propagation trend, so they are a good channel for indirect Dark Matter detection or to search new astrophysical sources.
TL;DR: In this article, the observed fluxes, spectra and sky distributions of the high energy diffuse backgrounds of astronomical neutrinos, gamma rays and cosmic ray positrons satisfy simple relations expected from their common production in hadronic collisions of high energy cosmic rays (CRs) with diffuse matter.
Abstract: We show that the observed fluxes, spectra and sky distributions of the high energy diffuse backgrounds of astronomical neutrinos, gamma rays and cosmic ray positrons satisfy simple relations expected from their common production in hadronic collisions of high energy cosmic rays (CRs) with diffuse matter This provides compelling evidence that the high energy neutrino, gamma ray, and positron backgrounds have a common origin - hadronic meson production by cosmic rays in our Galaxy and in external galaxies rather than through the decay/annihilation of dark matter particles
TL;DR: The High-Altitude Water Cherenkov Observatory (HAWC) is a TeV gamma-ray detector located at an altitude of 4100 meters on the slope of the Sierra Negra volcano in Puebla, Mexico as mentioned in this paper.
Abstract: — The High-Altitude Water Cherenkov Observatory (HAWC) is a TeV gamma-ray detector located at an altitude of 4100 meters on the slope of the Sierra Negra volcano in Puebla, Mexico. Inaugurated in March 2015, HAWC observes 65% of the sky every day with more than 90% duty cycle and an excellent angular resolution. HAWC plays an important role as a survey instrument for multi-wavelength studies, and presently is the most sensitive instrument to detect transients and extended sources of gamma-rays at multi-TeV energies. In this contribution I present the recent results from the experiment and discuss the future goals of the Collaboration.
TL;DR: In this article, a 5D, exact down to threshold, and polarised event generator is used to simulate key kinematic variables of a pair telescope and compare them to simulations with the low energy electromagnetic models available in Geant4 and in EGS5.
Abstract: — Gamma ray astronomy suffers from a sensitivity gap between 0.1 and 100 Mev. With high angular resolution for the electrons, it will also be possible to probe the linear polarisation of the photons. An accurate simulation is necessary to correctly design and compare these detectors. We establish baseline distributions of key kinematic variables as simulated by a 5D, exact down to threshold, and polarised event generator. We compare them to simulations with the low energy electromagnetic models available in Geant4 and in EGS5. We show that different generators give a different picture of the optimal angular resolution of pair telescopes. We also show that, of all the simulations we used, only the full 5D generator describes accurately the angular asymmetry in the case of polarised photons.
TL;DR: The IceCube experiment as mentioned in this paper is a high-energy neutrino detector which has been running in full operation since 2011 in the Antarctic ice at the geographic South Pole, with over 5000 photomultipliers submerged in a depth between 1.5 and 2.5 km.
Abstract: High-energy neutrinos provide a window to energetic astrophysical processes which is complementary to electromagnetic and cosmic-ray observations. Due to their low interaction cross-section they reach Earth from much more distant sources and point back directly to the primary hadronic interaction in which they were created, unlike high-energy photons which are absorbed by the extragalactic background light and often reprocessed once they reach Earth. Additionally, neutrinos are not deflected by magnetic fields which in principle makes them usable for pointing studies. These unique properties largely motivated the construction of the IceCube experiment, a high-energy neutrino detector which has been running in full operation since 2011 [1]. IceCube consists of over 5000 photomultipliers (PMTs) submerged in a depth between 1.5 and 2.5 km in the Antarctic ice at the geographic South Pole. The PMTs detect Cherenkov light emitted from charged secondary particles created in the neutrino interactions. Typical event topologies are either cascade-like (from charged-current νe interactions or neutralcurrent interactions) or track-like (charged-current νμ interactions). The background for astrophysical neutrinos comes from atmospheric neutrinos and muons originating from cosmic-ray interactions in the atmosphere.
TL;DR: In this article, the authors summarize the historical milestones that led to the first detection and report the perspectives of the field, and discuss the importance of the so-called multimessenger astronomy in which gravitational-wave sources will be observed in all bands of the electromagnetic spectrum with ground and space observatories and with neutrino telescopes.
Abstract: — Last years marked the beginning of a new era of observations of the Universe. Gravitational waves were detected from a binary black-hole merger by the Advanced LIGO detectors. Simultaneously, LISA Pathfinder demonstrated the technology for gravitational-wave observation in space beyond its planned requirements. Many gravitational observations and discoveries are expected in the next years with the Advanced LIGO and Virgo detectors, with strong impact on various astrophysical fields, from the physics governing compact object formation and evolution to the physics of the emission process and to nuclear astrophysics. I summarize here some historical milestones that led to the first detection and report the perspectives of the field. I also discuss the importance of the so-called multimessenger astronomy in which gravitational-wave sources will be observed in all bands of the electromagnetic spectrum with ground and space observatories and with neutrino telescopes.
TL;DR: Elena Cuoco, Jade Powell, Alejandro Torres-Forné, Ryan Lynch, Daniele Trifirò, Marco Cavaglià, Ik Siong Heng and José A. Font as mentioned in this paper.
Abstract: Elena Cuoco()(), Jade Powell(), Alejandro Torres-Forné(), Ryan Lynch(), Daniele Trifirò()(), Marco Cavaglià(), Ik Siong Heng() and José A. Font()() () European Gravitational Observatory (EGO) Via E. Amaldi, I-56021 Cascina, (PI) Italy () Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa Edificio C, Largo B. Pontecorvo 3, 56127 Pisa, Italy () SUPA, Institute for Gravitational Research, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK () Departamento de Astronomı́a y Astrof́ısica, Universitat de València Dr. Moliner 50, 46100, Burjassot (València), Spain () Massachusetts Institute of Technology 185 Albany St, 02139 Cambridge MA, USA () Dipartimento di Fisica E. Fermi, Università di Pisa Pisa 56127, Italy () Department of Physics and Astronomy, The University of Mississippi University, MS 38677, USA () Observatori Astronòmic, Universitat de València C/ Catedrático José Beltrán 2, 46980, Paterna (València), Spain