Paris Climate Agency

Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton–proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments—as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER—to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity ‘dark showers’, highlighting opportunities for expanding the LHC reach for these signals.

In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental physics. Given the very broad range of topics that might be relevant to LISA, we present here a sample of what we view as particularly promising directions, based in part on the current research interests of the LISA scientific community in the area of fundamental physics. We organize these directions through a "science-first" approach that allows us to classify how LISA data can inform theoretical physics in a variety of areas. For each of these theoretical physics classes, we identify the sources that are currently expected to provide the principal contribution to our knowledge, and the areas that need further development. The classification presented here should not be thought of as cast in stone, but rather as a fluid framework that is amenable to change with the flow of new insights in theoretical physics.

The Sun albedo of Cosmic Rays (CRs) at GeVs energy has been discovered recently by the FERMI satellite. They are traces of atmospheric CRs hitting solar atmosphere and reflecting skimming gamma photons. Even if relevant for astrophysics, as being a trace of atmospheric solar CR noises they cannot offer any signal of neutrino astronomy. On the contrary, the Moon with no atmosphere, may become soon a novel filtering calorimeter and an amplifier of energetic muon astronomical neutrinos (at TeV up to hundred TeVs energy); these lepton tracks leave an imprint in their beta decay while in flight to Earth. Their TeV electron air-shower are among the main signals. Also, a more energetic, but more rare, PeV up to EeV tau lunar neutrino events may be escaping as a tau lepton from the Moon: [Formula: see text] PeV secondaries, then, may be shining on Earth’s atmosphere in lunar shadows in a surprising way. One or a few gamma air-shower events inside the Moon shadows may occur each year in near future Cherenkov telescope array (CTA) or large high altitude air shower observatory (LHAASO) TeV gamma array detector, assuming a nonnegligible astrophysical TeV up to hundred TeV neutrino component (with respect to our terrestrial ruling atmospheric ones); these signals will open a new wonderful passe-partout keyhole for neutrino, been seen along the Moon. The lunar solid angle is small and the muon or tau expected rate is rare, but with the future largest tau radio array as the giant radio array for neutrino detection (GRAND), one might well discover such neutrino imprint.

We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the call for a Medium-size mission (M4). We consider three possible options for the telescope size: 1 m, 1.5 m and 2 m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1 m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations taking into account all the relevant foregrounds. Predictions for the various classes of extragalactic sources are based on up-to-date models. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies (by about a factor of 8 for the 1 m telescope, of 17 for 1.5 m, of 30 for 2 m), making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temperature distributions, etc.) across the Hubble sequence. Even more interestingly, COrE+ will detect, at |b| > 30°, thousands of strongly gravitationally lensed galaxies (about 2,000, 6,000 and 13,000 for the 1 m, 1.5 m and 2 m options, respectively). Such large samples are of extraordinary astrophysical and cosmological value in many fields. Moreover, COrE+ high frequency maps will be optimally suited to pick up proto-clusters of dusty galaxies, i.e. to investigate the evolution of large scale structure at larger redshifts than can be reached by other means. Thanks to its high sensitivity COrE+ will also yield a spectacular advance in the blind detection of extragalactic sources in polarization: we expect that it will detect up to a factor of 40 (1 m option) or of 160 (1.5 m option) more radio sources than can be detected by Planck and, for the first time, from several tens (1 m option) to a few hundreds (1.5 m option) of star forming galaxies. This will open a new window for studies of the global properties of magnetic fields in star forming galaxies and of their relationships with star formation rates.

We present a self-consistent interpretation of the of very-high-energy\nneutrino signal from the direction of the inner Galaxy, which is a part of the\nastronomical neutrino signal reported by IceCube. We demonstrate that an\nestimate of the neutrino flux in the E>100 TeV energy range lies at the\nhigh-energy power-law extrapolation of the spectrum of diffuse gamma-ray\nemission from the Galactic Ridge, as observed by Fermi telescope. This suggests\nthat IceCube neutrino and Fermi/LAT gamma-ray fluxes are both produced in\ninteractions of cosmic rays with the interstellar medium in the Norma arm\nand/or in the Galactic Bar. Cosmic rays responsible for the gamma-ray and\nneutrino flux are characterised by hard spectrum with the slope harder than\n-2.4 and cut-off energy higher than 10 PeV.\n

The ‘Internal Linear Combination’ (ILC) component separation method has been extensively used to extract a single component, the cosmic microwave background (CMB), from the WMAP multifrequency data. We generalize the ILC approach for separating other millimetre astrophysical emissions. We construct in particular a multidimensional ILC filter, which can be used, for instance, to estimate the diffuse emission of a complex component originating from multiple correlated emissions, such as the total emission of the Galactic interstellar medium. The performance of such generalized ILC methods, implemented on a needlet frame, is tested on simulations of Planck mission observations, for which we successfully reconstruct a low-noise estimate of emission from astrophysical foregrounds with vanishing CMB and Sunyaev–Zel’dovich contamination.

This article describes recent freight consultations in the Paris region (called the Ile de France) and assesses their usefulness to the urban freight policy. The Ile de France is one of 22 French regions, and is one of the largest and most developed metropolitan areas in Europe. It is currently confronting major economic, environmental, and institutional challenges. In this changing context, freight and logistics activities have been acknowledged as major contributors to the region’s economic well being that nonetheless have negative environmental effects such as noise, air pollution, and CO2 emissions. To manage freight transport in a more sustainable manner, the City of Paris and, more recently, the Ile-de-France Region,have engaged in consultations with freight transport firms, carriers’ organizations, and shippers’ associations. Our method is based on personal knowledge and experience, on a quantitative analysis of meeting records, and on interviews with local practitioners and elected officials. We examine consultations at three levels in the Ile de France Region’s institutional framework: the local level, represented by the “neighbourhood councils” in the city of Paris’s individual districts; the municipal level, with the Paris Delivery Charter experience (2006–2009); and the regional level, through the Ile-de-France Regional Council’s recent experiences with freight consultation. We analyse the difficulties encountered when conducting negotiations with the freight and logistics sectors in a complex urban environment. We describe the relationships between local and regional processes, showing how they have benefited from and sometimes overlapped with one another. Conditions for success are suggested, and a few guidelines are proposed.The Paris case leads to three conclusions. First of all, with regard to freight issues, specific consultations need to be implemented, because regular consultationsneglect freight transport issues. Secondly, freight consultations are of little use at the local and municipal levels. They need to be combined with metropolitan or region-wide consultation, because freight movement in urban areas is logistically connected to regional and national supply chains. Finally, it is important that consultation outcomes translate into effective changes in policies and behaviours. If not, well-intentioned freight companies willing to improve their urban operations will be discouraged from doing so and the very purpose of freight consultations, which is to promote more efficient and sustainable urban supply chains based on voluntary commitments, will be lost.