INFN Sezione di Napoli

Since its first observation in the 1970s, neutrino-induced neutral-current single positive pion production (NC1π^{+}) has remained an elusive and poorly understood interaction channel. This process is a significant background in neutrino oscillation experiments and studying it further is critical for the physics program of next-generation accelerator-based neutrino oscillation experiments. In this Letter, we present the first double-differential cross-section measurement of NC1π^{+} interactions using data from the ND280 detector of the T2K experiment collected in ν-beam mode. The measured flux-averaged integrated cross section is σ=(6.07±1.22)×10^{-41} cm^{2}/nucleon. We compare the results on a hydrocarbon target to the predictions of several neutrino interaction generators and final-state-interaction models. While model predictions agree with the differential results, the data show a weak preference for a cross-section normalization approximately 30% higher than predicted by most models studied in this Letter.

Abstract We present the X-ray polarization observation of G21.5−0.9, a young Galactic supernova remnant (SNR), conducted with the Imaging X-ray Polarimetry Explorer (IXPE) in 2023 October, with a total livetime of approximately 837 ks. Using different analysis methods, such as a space-integrated study of the entire region of the pulsar wind nebula (PWN) and a space-resolved polarization map, we detect significant polarization from the PWN at the center of the SNR, with an average polarization degree of ∼10% oriented at ∼33° (north through east). No significant energy-dependent variation in polarization is observed across the IXPE band (2–8 keV). The polarization map, corrected for the effect of polarization leakage, reveals a consistent pattern in both degree and angle, with little change across the nebula. Our findings indicate the presence of a highly polarized central torus, suggesting low levels of turbulence at particle acceleration sites. Unlike Vela, but similar to the Crab Nebula, we observe substantial differences between radio and X-ray polarization maps. This suggests a clear separation in energy of the emitting particle populations and hints at an important, yet poorly understood, role of instabilities in the turbulence dynamics of PWNe.

In this work, we develop a generic formalism for the study of cosmological tensor perturbations induced at second order by first-order vector metric perturbations, dubbing these induced tensor modes vector-induced gravitational waves (VIGWs). In the presence of an active source such as primordial magnetic fields (PMFs), the vector perturbations of the metric do not necessarily decay rapidly with Hubble expansion, but may remain significantly large in amplitude depending upon the background equation-of-state (EoS) parameter, w, during reheating. Considering an inflation-inspired PMF power spectrum of the power-law form PB (k) ∝ k n B (where n B is the magnetic spectral index), we show that the VIGW signal is enhanced for a stiff post-inflationary EoS, with the maximum enhancement happening for w = 1 (kination). The VIGW spectrum exhibits a maximum around the scale crossing the cosmological horizon at the end of reheating, k reh, while its present day peak amplitude scales as ΩGW(k reh,η 0) ∝ [10ΔN reh (H inf/M Pl)]8, where H inf is the Hubble parameter at the end of inflation and ΔN reh is the duration of the post-inflationary era in e-folds. For w = 1 and n B > -3/2, one further obtains a nearly n B-independent frequency scaling of the GW spectrum of the form ΩGW(f,η 0) ∝ (f/f reh)-2.8 for f > f reh ≡ k reh/(2π). We also explicitly demonstrate that the VIGW spectrum is dominant over that of the first-order magnetically-sourced GWs from the reheating era. Finally, it is highlighted that the VIGW signal may lie well within the detection bands of several next-generation interferometric GW missions at small scales. Indicatively, for H inf ∼ O(107) GeV and O(1014) GeV, and ΔN reh ∼ 15 and 10, the VIGW signal is found to be detectable by LISA and ET respectively.

In https://doi.org/10.1088/1475-7516/2024/11/051JCAP11(2024)051, we discussed how different regimes (flavoured) of leptogenesis can be probed through a “tomographic” approach using primordial gravitational waves. By examining the theory's parameter space, we identified regions where right-handed neutrino mass-dependent non-standard cosmological expansion leaves characteristic imprints on propagating gravitational waves. Our analysis focused on inflationary blue-tilted gravitational waves, modeled by a power-law tensor power spectrum with a constant spectral index. The resulting double-peak spectrum — where peak and dip frequencies are sensitive to leptogenesis parameters — provided marked signatures of different leptogenesis regimes. In this follow-up article, we conduct a statistical analysis of two-flavour leptogenesis signals, particularly those producing a peak (more generally, a broken power-law signal) within the LISA frequency band. Using a Fisher matrix analysis, we delineate the regions of parameter space that LISA can probe with minimal uncertainty, accounting for galactic and extragalactic foregrounds along with LISA's instrumental noise.

Limonium gmelini (Willd.) Kuntze, a plant widely used in traditional medicine, has garnered increasing attention for its diverse pharmacological activities, including anti-inflammatory, hepatoprotective, antioxidant, and antimicrobial effects. This study aimed to explore the chemical composition and biological activities of polysaccharides and polyphenolic compounds extracted from both the roots and aboveground parts of Limonium gmelini. Several methods of extraction, including ultrasound-assisted extraction (UAE), conventional maceration (CM), and supercritical fluid extraction (SFE), were employed to obtain bioactive fractions. Chemical profiling, primarily represented by monosaccharides and polyphenolic compounds, was characterized and analyzed using proton nuclear magnetic resonance spectroscopy (1H-NMR) and gas chromatography-mass spectrometry (GC-MS) techniques. While polyphenol-rich fractions exhibited significant antibacterial activity, particularly against Staphylococcus epidermidis, polysaccharide-rich aqueous fractions showed minimal antibacterial activity. Among the methods, CM and UAE yielded higher polyphenol content, whereas SFE provided more selective extractions. Notably, methanolic SPE fractions derived from the roots were especially enriched in active polyphenols such as gallic acid, myricetin, and naringenin, and they exhibited the highest antibacterial activity against Staphylococcus epidermidis. In contrast, extracts from the aboveground parts showed more moderate activity and a partially different chemical profile. These findings underscore the importance of plant part selection and support the targeted use of root-derived polyphenol-enriched fractions from L. gmelini as promising candidates for the development of natural antibacterial agents. Further investigation is needed to isolate and validate the most active constituents for potential therapeutic applications.

A new measurement of the magnetic anomaly $a_{\mu}$ of the positive muon is presented based on data taken from 2020 to 2023 by the Muon $g-2$ Experiment at Fermi National Accelerator Laboratory (FNAL). This dataset contains over 2.5 times the total statistics of our previous results. From the ratio of the precession frequencies for muons and protons in our storage ring magnetic field, together with precisely known ratios of fundamental constants, we determine $a_{\mu} = 116\,592\,0710(162) \times 10^{-12}$ (139 ppb) for the new datasets, and $a_{\mu} = 116\,592\,0705(148) \times 10^{-12}$ (127 ppb) when combined with our previous results. The new experimental world average, dominated by the measurements at FNAL, is $a_{\mu}(\text{exp}) =116\,592\,0715(145) \times 10^{-12}$ (124 ppb). The measurements at FNAL have improved the precision on the world average by over a factor of four.

We investigate the emergence and properties of long-distance genuine multipartite entanglement, induced via three localized magnetic defects, in a one-dimensional transverse-field $XX$ spin-$1/2$ chain. Using both analytical and numerical techniques, we determine the conditions for the existence of bound states localized at the defects. We find that the reduced density matrix (RDM) of the defects exhibits long-distance genuine multipartite entanglement (GME) across the whole range of the Hamiltonian parameter space, including regions where the two-qubit concurrence is zero. We quantify the entanglement by using numerical lower bounds for the GME concurrence, as well as by analytically deriving the GME concurrence in regions where the RDM is of rank 2. Our work provides insights into generating multipartite entanglement in many-body quantum systems via local control techniques.

We investigate high and low energy implications of a gauge dual description of the Standard Model. The high energy electric theory features gauge dynamics involving only fermionic matter fields, while the low energy magnetic description features a quasisupersymmetric spectrum testable at colliders. The flavor theory is constructed via operators generated at the Planck scale, possibly by gravitational global symmetry breaking interactions. We further show that duality opens novel avenues for theories of grand unification.

Abstract The gravitational interaction, as described by the Einstein–Cartan theory, is shown to emerge as the by-product of the spontaneous symmetry breaking of a gauge symmetry in a pre-geometric four-dimensional spacetime. Starting from a formulation a ` la Yang–Mills on an SO ( 1 , 4 ) or SO ( 3 , 2 ) principal bundle and not accounting for a spacetime metric, the Einstein–Hilbert action is recovered after the identification of the effective spacetime metric and spin connection for the residual SO ( 1 , 3 ) gauge symmetry of the spontaneously broken phase—i.e. the stabiliser of the SO ( 1 , 4 ) or SO ( 3 , 2 ) gauge group. Thus, the two fundamental tenets of general relativity, i.e. diffeomorphism invariance and the equivalence principle, can arise from a more fundamental gauge principle. The two mass parameters that characterise Einstein gravity, namely the Planck mass and the cosmological constant, are likewise shown to be emergent. The phase transition from the unbroken to the spontaneously broken phase is expected to happen close to the Planck temperature. This is conjectured to be dynamically driven by a scalar field that implements a Higgs mechanism, hence providing mass to new particles, with consequences for cosmology and high-energy physics. The couplings of gravity to matter are discussed after drawing up a dictionary that interconnects pre-geometric and effective geometric quantities. In the unbroken phase where the fundamental gauge symmetry is restored, the theory is potentially power-counting renormalisable without matter, offering a novel path towards a UV completion of Einstein gravity.

Ultra-light primordial black holes (PBHs) with masses M PBH < 5 × 108g can dominate transiently the energy budget of the Universe and reheat the Universe through their evaporation taking place before Big Bang Nucleosynthesis. The isocurvature energy density fluctuations associated to the inhomogeneous distribution of a population of such PBHs can induce an abundant production of GWs due to second-order gravitational effects. In this work, we discuss the effect of primordial non-Gaussianity on the clustering properties of PBHs and study the effect of a clustered PBH population on the spectral shape of the aforementioned induced GW signal. In particular, focusing on local-type non-Gaussianity we find a double-peaked GW signal with the amplitude of the low-frequency peak being proportional to the square of the non-Gaussian parameter τ NL. Remarkably, depending on the PBH mass M PBH and the initial abundance of PBHs at formation time, i.e. ΩPNH,f, this double-peaked GW signal can lie well within the frequency bands of forthcoming GW detectors, namely LISA, ET, SKA and BBO, hence rendering this signal falsifiable by GW experiments and promoting it as a novel portal probing the primordial non-Gaussianity.