In this talk I will focus on the physics of Binary Neutron Stars merger obtained from numerical simulations of the Einstein equations coupled to matter. The results are obtained using a semi-realistic descriptions of the equation of state (EOS), where the EOS is described by a seven-segment piece-wise polytropic and a thermal component. One of the important characteristics of the present investigation is that it is entirely performed using only publicly available open source software, the Einstein Toolkit for the dynamical evolution and the LORENE code for the generation of the initial models. After the gravitational-wave event GW150914, observed by the LIGO/Virgo collaboration, the new eve of Gravitational Wave physics has just began and it is clear that accurate modelling of the gravitational wave signal emitted by compact binary sources will play a prominent role. In particular I will present results for the gravitational wave-signal obtained from three-dimensional numerical simulations of the dynamics of binary neutron star (BNS) mergers from the late stage of the inspiral process up to about 20 ms after the system has merged, either to form a hyper-massive neutron star (NS) or a rotating black hole (BH).

Scopri di più »# Tag Archives: Evento scientifico

## Strangeness, Gravitational waves and neutron stars

ONE DAY MEETING Strangeness, Gravitational waves and neutron stars 10 June 2016 INFN-LNF Aula di Direzione (Ed. 1) The meeting is centred on the most recent developments and findings in the strangeness physics, in particular the possible role of strangeness in neutron stars, on the discovery of gravitational waves and on the future of these fields, considering that a copious source of gravitational waves are expected to be the binaries of neutron stars. Combining the theoretical and experimental findings in these sectors will allow a better and more accurate understanding of the involved processes, at the crossroad between strong interaction and general relativity. Organizers: Catalina Oana Curceanu, Maria Paola Lombardo Speakers include: Omar Benhar (INFN Sapienza), Ignazio Bombaci (Univ. e INFN Pisa), Alessandro Drago (Univ. e INFN Ferrara, Italy) Viviana Fafone (ToV), Alessandra Feo (Univ. Perugia), Massimo Mannarelli (LNGS), Kristian Piscicchia (LNF-INFN e Centro Fermi, Roma), Jacobus Verbaarschot (SUNY),

Scopri di più »## A short walk through the physics of neutron stars

Neutron stars are excellent observatories to test our present understanding of the theory of strong interacting matter at extreme conditions, and they offer an interesting interplay between nuclear processes and astrophysical observables. Conditions of matter inside neutron stars are very different from those one can find in Earth and, therefore, a good knowledge of the equation of state of dense matter is required to understand the properties of neutron stars. On the first part of this talk I will briefly review some of the general properties of these fascinating objects. On the second part, I will revise the problem of the strong softening of the EoS, and the consequent reduction of the maximum mass, induced by the presence of hyperons in the neutron star interior, a puzzle which has become more intringuing and difficult to solve due the recent measurements of the unusually high masses of the millisecond pulsars PSR J1903+0327 ($1.667\pm 0.021 M_\odot$), PSR J1614-2230 ($1.97 \pm 0.04 M_\odot$), and PSR J0348+0432 ($2.01 pm 0.04 M_\odot$). Finally, I will also examine the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

Scopri di più »## Mathematics and Physics at the Crossroads

Mathematicians and theoretical physicists meet and discuss outstanding issues and future research directions at the crossroads of Gauge Fields, Strings and Holography Operator Algebras and Quantum Field Theory Condensed Matter and Critical Phenomena an INdAM intensive period framed within the cooperation agreement between CMTP and INFN The program runs from June 6 to July 29 and from August 22 until September 30, 2016. Its purpose is to bring together leading international experts and talented young researchers in mathematics and theoretical physics, especially in Algebra, Operator Algebras, Geometry, Statistical Mechanics, Quantum Field Theory and String Theory, in order to stimulate interaction and cross-fertilization between these disciplines. The format includes seminars, informal meetings and three topical workshops on Operator Algebras and Quantum Field Theory, Gauge and String Theory, Condensed Matter and Critical Phenomena. A Mathematical Physics school is planned as well. Office space, meeting rooms and access to the LNF Library will be provided. We welcome the participation of students and young postdocs. October 7, 2016 Beyond the Crossroads… The program has concluded, and thanks to anyone who has helped making it a success! One-day concluding event will take place at INdAM on October 27

Scopri di più »## Una possibile partecipazione INFN al progetto Qubic

L’esperimento Qubic si propone la misura dei modi B di polarizzazione con una sensibilità sul parametro r (rapporto tra l’ampiezza delle perturbazioni tensoriali/scalari) pari a circa 2×10-2 in tre anni di presa dati. Si tratta di un passo ulteriore nel miglioramento dell’attuale limite di Bicep2+Planck (r

Scopri di più »## The Horizon2020 EuPRAXIA Project – Towards a Groundbreaking European Plasma Accelerator

Particle accelerators based on RF systems have been a remarkable success story since they were proposed 90 years ago by Ising and demonstrated experimentally by Wideröe. Today there are some 30,000 accelerators world-wide, from small industrial accelerators to the Large Hadron Collider, one of mankind largest machines. The maximum beam energy in particle accelerators has for many years followed an exponential increase with time, the so-called Livingston curve. However, progress has slowed down significantly over the last years. At the same time the new technology of plasma-based electron accelerators has emerged with exponential progress since 1980. Acceleration lengths are a factor 100-1000 shorter than in conventional accelerators. Plasmas excited by industrially available lasers have produced accelerating gradients of up to 100 GV/m and electrons at energies up to 4.25 GeV, promising a revolution in the way accelerators are built. Much more compact and cost-effective accelerators can be imagined. The potential of this technology is discussed. National and international activities are summarized. Special emphasis will be placed on the “European Plasma Research Accelerator with Excellence in Applications” (EuPRAXIA) project, the second accelerator-related EU design study in Horizon2020. This EU-financed study aims at proposing a European Research Infrastructure that pioneers a compact plasma accelerator for applications in photon science, High Energy Physics and other fields, like medical imaging applications. EuPRAXIA is supported by a consortium of 16 member institutes and presently 15 associated partner labs in Europe, Asia and the US.

Scopri di più »## Implications of unitarity for the 750 GeV di-photon excess

By employing partial wave unitarity arguments I show that: i) the effective description of the di-photon excess in terms of the SM supplemented by a single scalar resonance breaks down at scales of few tens of TeV and ii) in the large width scenario (as hinted by ATLAS) perturbative calculability is endangered in many renormalizable models. I finally discuss under which conditions the data can be accommodated within weakly coupled models.

Scopri di più »## Giornata Informativa Bandi H2020

## 51st Scientific Committee Meeting

## Observation of the e+ e-decay of a light, neutral boson created in a nuclear transition

Recently, several experimental anomalies were discussed as possible signatures for a new light particle. In order to search for such signatures, we have measured the e+e- angular correlation in internal pair creation (IPC) for the the M1 transitions depopulating the 17.6 and 18.15 MeV states in 8Be, and observed anomalous IPC in the latter transition. The observed deviations from the M1 IPC in the case of the 17.6 MeV transition could be explained by the contribution of the background, which has E1 multipolarity. However, E1 or any other mixing cannot explain the measured peak-like deviation in the case of the 18 MeV transition. The deviation between the experimental and theoretical angular correlations is significant and can be described by assuming the creation and subsequent decay of a boson with mass M0c2 =16.70 MeV. The branching ratio of the e+e- decay of such a boson to the photon decay of the 18.15 MeV level of 8Be is found to be 5-8×10-6 for the best fit. Such a boson might be a good candidate for the relatively light U(1)d gauge boson, or the light mediator of the escluded WIMP dark matter scenario, or the dark photon, or the dark Z (Zd) suggested for explaining the muon anomalous magnetic moment. I am going to show the reliability of the data obtained, which will place such a particle into context with other experimental results, and discuss their implications.

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