Bootstrapping Newton Gravity

A non-linear equation obtained by adding gravitational self-interaction terms to the Poisson equation for Newtonian gravity is here employed in order to analyse a static spherically sym- metric homogeneous compact source of given proper mass and radius and the outer vacuum. The main feature of this picture is that, although the freedom of shifting the potential by an ar- bitrary constant is of course lost, the solutions remain qualitatively very close to the Newtonian behaviour. We also notice that the negative gravitational potential energy is smaller than the proper mass for sources with small compactness, but for sources that should form black holes according to General Relativity, the gravitational potential energy becomes of the same order of magnitude of the proper mass, or even larger. Moreover, the pressure overcomes the energy density for large values of the compactness, but it remains finite for finite compactness, hence there exists no Buchdahl limit. This classical description is meant to serve as the starting point for investigating quantum features of (near) black hole configurations within the corpuscular picture of gravity in future developments.Comment: 23 pages, 20 plots. New section and appendix about stability and the pressure clarify comparison with GR. Conclusions rewritten to make motivations cleare

Probing new physics in diphoton production with proton tagging at the Large Hadron Collider

The sensitivities to anomalous quartic photon couplings at the Large Hadron Collider are estimated using diphoton production via photon fusion. The tagging of the protons proves to be a very powerful tool to suppress the background and unprecedented sensitivities down to $6 \cdot 10^{-15}$\gev$^{-4}$ are obtained, providing a new window on extra dimensions and strongly-interacting composite states in the multi-TeV range. Generic contributions to quartic photon couplings from charged and neutral particles with arbitrary spin are also presented.Comment: 4 pages, 3 figure

Dark particle mass effects on neutron star properties from a short-range correlated hadronic model

In this work we study a relativistic mean-field (RMF) hadronic model, with nucleonic short-range correlations (SRC) included, coupled to dark matter (DM) through the Higgs boson. We study different parametrizations of this model by running the dark particle Fermi momentum, and its mass in the range of $50$ GeV $\leqslant M_\chi\leqslant 500$ GeV, compatible with experimental spin-independent scattering cross-sections. By using this RMF-SRC-DM model, we calculate some neutron star quantities, namely, mass-radius profiles, dimensionless tidal deformabilities, and crustal properties. Our findings show that is possible to construct RMF-SRC-DM parametrizations in agreement with constraints provided by LIGO and Virgo collaboration (LVC) on the GW170817 event, and recent observational data from the NICER mission. Furthermore, we show that the increase of $M_\chi$ favors the model to attain data from LVC regarding the tidal deformabilities. Higher values of $M_\chi$ also induce a reduction of the neutron star crust (mass and thickness), and cause a decrease of the crustal fraction of the moment of inertia ($I_{\rm{\tiny crust}}/I$). Nevertheless, we show that some RMF-SRC-DM parametrizations still exhibit $I_{\rm{\tiny crust}}/I>7\%$, a condition that explains the glitch activity in rotation-powered pulsars such as the Vela one. Therefore, dark matter content can also be used for describing such a phenomenon.Comment: 10 pages, 8 figures. Published in Monthly Notices of the Royal Astronomical Societ

Shell model analysis of the B(E2, 2+ → 0+) values in the A = 70, T = 1 triplet 70Kr, 70Br, and 70Se

The B(E2, 2+ → 0+) transition strengths of the T = 1 isobaric triplet 70Kr, 70Br, 70Se, recently measured at the RIKEN Radioactive Isotope Beam Factory (RIBF), are discussed in terms of state-of-the-art large scale shell model calculations using the JUN45 and JUN45+LNPS plus Coulomb interactions. In this Letter we argue that, depending on the effective charges used, the calculations are either in line with the experimental data within statistical uncertainties, or the anomaly happens in 70Br, rather than 70Kr. In the latter case, we suggest that it can be due to the presence of a hitherto undetected 1+ T = 0 state below the yrast 2+ T = 1 state. Our results do not support a shape change of 70Kr with respect to the other members of the isobaric multiple

Consistent Skyrme parametrizations constrained by GW170817

The high-density behavior of the stellar matter composed of nucleons and leptons under $\beta$~equilibrium and charge neutrality conditions is studied with the Skyrme parametrizations shown to be consistent (CSkP) with the nuclear matter, pure neutron matter, symmetry energy and its derivatives in a set of $11$ constraints [Dutra {\it et al.}, Phys. Rev. C 85, 035201 (2012)]. The predictions of these parametrizations on the tidal deformabilities related to the GW170817 event are also examined. The CSkP that produce massive neutron stars give a range of 11.86~\mbox{km} \leqslant R_{1.4} \leqslant 12.55~\mbox{km} for the canonical star radius, in agreement with other theoretical predictions. It is shown that the CSkP are compatible with the region of masses and radii obtained from the analysis of recent data from LIGO and Virgo Collaboration (LVC). A correlation between dimensionless tidal deformability and radius of the canonical star is found, namely, $\Lambda_{1.4} \approx 3.16\times10^{-6}R_{1.4}^{7.35}$, with results for the CSkP compatible with the recent range of $\Lambda_{1.4}=190_{-120}^{+390}$ from LVC. An analysis of the $\Lambda_1\times\Lambda_2$ graph shows that all the CSkP are compatible with the recent bounds obtained by LVC. Finally, the universal correlation between the moment of inertia and the deformability of a neutron star, named as the \mbox{$I$-Love} relation, is verified for the CSkP, that are also shown to be consistent with the prediction for the moment of inertia of the \mbox{PSR J0737-3039} primary component pulsar.Comment: 10 pages, 7 figure