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We revise the cosmological phenomenology of Macroscopic Dark Matter (MDM) candidates, also commonly dubbed as Macros. A possible signature of MDM is the capture of baryons from the cosmological plasma in the pre-recombination epoch, with the consequent injection of high-energy photons in the baryon-photon plasma. By keeping a phenomenological approach, we consider two broad classes of MDM in which Macros are composed either of ordinary matter or antimatter. In both scenarios, we also analyze the impact of a non-vanishing electric charge carried by Macros. We derive constraints on the Macro parameter space from three cosmological processes: the change in the baryon density between the end of the Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB) decoupling, the production of spectral distortions in the CMB and the kinetic coupling between charged MDM and baryons at the time of recombination. In the case of neutral Macros we find that the tightest constraints are set by the baryon density condition in most of the parameter space. For Macros composed of ordinary matter and with binding energy \\(I\\), this leads to the following bound on the reduced cross-section: \\(\\sigma_X/M_X \\lesssim 6.8 \\cdot 10^{-7} \\left(I/\\mathrm{MeV}\\right)^{-1.56} \\, \\text{cm}^2 \\, \\text{g}^{-1}\\). Charged Macros with surface potential \\(V_X\\), instead, are mainly constrained by the tight coupling with baryons, resulting in \\(\\sigma_X/M_X \\lesssim 2 \\cdot 10^{-11} \\left(|V_X|/\\mathrm{MeV}\\right)^{-2} \\text{cm}^2 \\, \\text{g}^{-1}\\). Finally, we show that future CMB spectral distortions experiments, like PIXIE and SuperPIXIE, would have the sensitivity to probe larger regions of the parameter space: this would allow either for a possible evidence or for an improvement of the current bounds on Macros as dark matter candidates.

We constrain the coupling of thermally-produced axion-like particles (here axions) with photons and gluons, using data from the cosmic microwave background (CMB) spectra and baryon acoustic oscillations. The axion possesses an explicit soft breaking mass term and it is produced thermally in the early Universe from either axion-photon or axion-gluon processes, accounting for the recent progresses in the field. We derive the most stringent bounds on the axion-gluon coupling to date on the mass range considered \\(10^{-4} \\lesssim m_a/{\\rm eV} \\lesssim 100\\), superseding the current bounds from SN1987A. The bounds on the axion-photon coupling are competitive with the results from the CAST collaboration for the axion mass \\(m_a \\gtrsim 3\\,\\)eV. We comment on the forecast reaches that will be available given the sensitivity of future CMB-S4 missions.

We perform a comprehensive study of the signatures of Lorentz violation in electrodynamics on the Cosmic Microwave Background (CMB) anisotropies. In the framework of the minimal Standard Model Extension (SME), we consider effects generated by renormalizable operators, both CPT-odd and CPT-even. These operators are responsible for sourcing, respectively, cosmic birefringence and circular polarization. We propagate jointly the effects of all the relevant Lorentz-violating parameters to CMB observables and provide constraints with the most recent CMB datasets. We bound the CPT-even coefficient to \\(k_{F,E+B} < 2.31 \\times 10^{-31}\\) at 95\\% CL. This improves previous CMB bounds by one order of magnitude. The limits we obtain on the CPT-odd coefficients, i.e. \\(|k_{(V)00}^{(3)}| < 1.54 \\times 10^{-44} \\; {\\rm GeV}\\) and \\(|\\mathbf{k_{AF}}| < 0.74 \\times 10^{-44} \\; {\\rm GeV}\\) at 95\\% CL, are respectively one and two orders of magnitude stronger than previous CMB-based limits, superseding also bounds from non-CMB searches. This analysis provides the strongest constraints to date on CPT-violating coefficients in the minimal SME from CMB searches.

Violation of parity symmetry in the gravitational sector, which manifests into unequal left and right circular polarization states of primordial gravitational waves, represents a way to test high-energy modifications to general relativity. In this paper we study inflation within recently proposed chiral scalar-tensor theories of gravity, that extend Chern-Simons gravity by including parity-violating operators containing first and second derivatives of the non-minimally coupled scalar (inflaton) field. Given the degeneracy between different parity-violating theories at the level of the power spectrum statistics, we make a detailed analysis of the parity violation on primordial tensor non-Gaussianity. We show, with an explicit computation, that no new contributions arise in the graviton bispectra if the couplings in the new operators are constant in a pure de Sitter phase. On the other hand, if the coupling functions are time-dependent during inflation, the tensor bispectra acquire non-vanishing contributions from the parity-breaking operators even in the exact de Sitter limit, with maximal signal in the squeezed and equilateral configurations. We also comment on the consistency relation of the three-point function of tensor modes in this class of models and discuss prospects of detecting parity-breaking signatures through Cosmic Microwave Background \\(B\\)-mode bispectra.

Cosmological observations allow to measure the abundance of light relics produced in the early Universe. Most studies focus on the thermal freeze-out scenario, yet light relics produced by freeze-in are generic for models in which new light degrees of freedom do not couple strongly enough to the Standard Model (SM) plasma to allow for full thermalization in the early Universe. In ultraviolet (UV) freeze-in scenarios, rates for light relic production associated with non-renormalizable interactions typical of beyond the SM (BSM) models grow with temperature more quickly than the Hubble rate. Thus, relatively small couplings to the SM can be probed by current and next-generation cosmic microwave background (CMB) experiments. We investigate several representative benchmark BSM models, such as axion-like particles from Primakoff production, massless dark photons and light right-handed neutrinos. We calculate contributions to the effective number of neutrino species, \\(\\Delta N_{\\rm eff}\\), in corners of parameter space not previously considered and discuss the sensitivity of CMB experiments compared to other probes. In contrast to freeze-out scenarios, \\(\\Delta N_{\\rm eff}\\) from UV freeze-in is more dependent on both the specific BSM physics model and the reheating temperature. Depending on the details of the BSM scenario, we find that the sensitivity of next-generation CMB experiments can complement or surpass the current astrophysical, laboratory or collider constraints on the couplings of the SM to the light relic.

Oral colon delivery has widely been pursued exploiting naturally occurring polysaccharides degraded by the resident microbiota. However, their hydrophilicity may hinder the targeting performance. The aim of the present study was to manufacture and evaluate a double-coated delivery system leveraging intestinal microbiota, pH, and transit time for reliable colonic release. This system comprised a tablet core, a hydroxypropyl methylcellulose (HPMC) inner layer and an outer coating based on Eudragit ® S and guar gum. The tablets were loaded with paracetamol, selected as a tracer drug because of the well-known analytical profile and lack of major effects on bacterial viability. The HPMC and Eudragit ® S layers were applied by film-coating. Tested for in vitro release, the double-coated systems showed gastroresistance in 0.1 N HCl followed by lag phases of consistent duration in phosphate buffer pH 7.4, imparted by the HPMC layer and synergistically extended by the Eudragit ® S/guar gum one. In simulated colonic fluid with fecal bacteria from an inflammatory bowel disease patient, release was faster than in the presence of β -mannanase and in control culture medium. The bacteria-containing fluid was obtained by an experimental procedure making multiple tests possible from a single sampling and processing run. Thus, the study conducted proved the feasibility of the delivery system and ability of guar gum to trigger release in the presence of colon bacteria without impairing the barrier properties of the coating. Finally, it allowed an advantageous simulated colonic fluid preparation procedure to be set up, reducing the time, costs, and complexity of testing and enhancing replicability. Graphical abstract