Constraints on secret neutrino interactions after Planck

(Abridged) Neutrino interactions beyond the standard model may affect the cosmological evolution and can be constrained through observations. We consider the possibility that neutrinos possess secret scalar or pseudoscalar interactions mediated by the Nambu-Goldstone boson of a still unknown spontaneously broken global $U(1)$ symmetry, as in, e.g. , Majoron models. In such scenarios, neutrinos still decouple at $T\simeq 1$ MeV, but become tightly coupled again ('recouple') at later stages of the cosmological evolution. We use available observations of CMB anisotropies, including Planck 2013 and the joint BICEP2/Planck 2015 data, to derive constraints on the quantity $\gamma_{\nu \nu}^4$, parameterizing the neutrino collision rate due to (pseudo)scalar interactions. We consider both a minimal extension of the standard $\Lambda$CDM model, and scenarios with extra relativistic species or non-vanishing tensors. We find a typical constraint $\gamma_{\nu \nu}^4 < 0.9\times 10^{-27}$ (95% C.L.), implying an upper limit on the redshift $z_{rec}$ of neutrino recoupling $< 8500$. In the framework of Majoron models, the upper limit on $\gamma_{\nu \nu}$ roughly translates on a constraint $g < 8.2\times 10^{-7}$ on the Majoron-neutrino coupling constant $g$. In general, the data show a weak ($\sim 1\sigma$) but intriguing preference for non-zero values of $\gamma_{\nu \nu}^4$, with best fits in the range $\gamma_{\nu \nu}^4 = (0.15 - 0.35)\times 10^{-27}$, depending on the particular dataset. This is more evident when either observations from ACT and SPT are included, or the possibility of non-vanishing tensor modes is considered. In particular, for the minimal model $\Lambda$CDM +$\gamma_{\nu \nu}$ and including the Planck 2013, ACT and SPT data, we report $\gamma_{\nu \nu}^4=( 0.45^{+0.15}_{-0.38} )\times10^{-27}$ ($200 < z_{rec} < 5700$) at 68% confidence level.Comment: 19 pages, 7 figures, 3 tables. Replaced to match version accepted for pubblication in JCA

Cosmic microwave background constraints on secret interactions among sterile neutrinos

Secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson $X$ (with $M_X \ll M_W$), and characterized by a gauge coupling $g_X$, have been proposed as a mean to reconcile cosmological observations and short-baseline laboratory anomalies. We constrain this scenario using the latest Planck data on Cosmic Microwave Background anisotropies, and measurements of baryon acoustic oscillations (BAO). We consistently include the effect of secret interactions on cosmological perturbations, namely the increased density and pressure fluctuations in the neutrino fluid, and still find a severe tension between the secret interaction framework and cosmology. In fact, taking into account neutrino scattering via secret interactions, we derive our own mass bound on sterile neutrinos and find (at 95% CL) $m_s < 0.82$ eV or $m_s < 0.29$ eV from Planck alone or in combination with BAO, respectively. These limits confirm the discrepancy with the laboratory anomalies. Moreover, we constrain, in the limit of contact interaction, the effective strength $G_X$ to be $< 2.8 (2.0) \times 10^{10}\,G_F$ from Planck (Planck+BAO). This result, together with the mass bound, strongly disfavours the region with $M_X \sim 0.1$ MeV and relatively large coupling $g_X\sim 10^{-1}$, previously indicated as a possible solution to the small scale dark matter problem.Comment: 15 pages, 3 figures, 4 table

Thermal axions with multi-eV masses are possible in low-reheating scenarios

We revise cosmological mass bounds on hadronic axions in low-reheating cosmological scenarios, with a reheating temperature $T_{\rm RH}~\le 100$ MeV, in light of the latest cosmological observations. In this situation, the neutrino decoupling would be unaffected, while the thermal axion relic abundance is suppressed. Moreover, axions are colder in low-reheating temperature scenarios, so that bounds on their abundance are possibly loosened. As a consequence of these two facts, cosmological mass limits on axions are relaxed. Using state-of-the-art cosmological data and characterizing axion-pion interactions at the leading order in chiral perturbation theory, we find in the standard case an axion mass bound $m_a < 0.26$ eV. However, axions with masses $m_a \simeq 1$ eV, or heavier, would be allowed for reheating temperatures $T_{\rm RH} \lesssim 80$ MeV. Multi-eV axions would be outside the mass sensitivity of current and planned solar axion helioscopes and would demand new experimental approaches to be detected.Comment: v2: minor changes to match the version published on JCAP. 27 pages, 10 figure

Simulating the development and progression of Chronic Kidney Disease and osteoporosis in people living with HIV

The "chronicization" of HIV infection brings about a growing necessity to attentively evaluate current and potential complications when prescribing the individual therapeutic regimen. Starting from this need, we developed two HIV-comorbidity simulators that, basing on the evidence available in medical literature and starting from the current clinical and demographic features of the individual patient, project and compare the risks of developing and worsening of nephropathy and osteopathy associated with possible ARV regimens. These simulators are embedded in a desktop, user-friendly software thought to be used by the treating physician during prescription discussion with his/her patients, in order to highlight expected clinical outcomes and healthcare resource consumption that may differ according to the therapeutic strategy selected. In this article we present the sources and methods used in developing the mathematical models, alongside a set of examples and the results of cohort-level validation runs

Association of COVID-19 Vaccinations With Intensive Care Unit Admissions and Outcome of Critically Ill Patients With COVID-19 Pneumonia in Lombardy, Italy

IMPORTANCE Data on the association of COVID-19 vaccination with intensive care unit (ICU) admission and outcomes of patients with SARS-CoV-2-related pneumonia are scarce. OBJECTIVE To evaluate whether COVID-19 vaccination is associated with preventing ICU admission for COVID-19 pneumonia and to compare baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort study on regional data sets reports: (1) daily number of administered vaccines and (2) data of all consecutive patients admitted to an ICU in Lombardy, Italy, from August 1 to December 15, 2021 (Delta variant predominant). Vaccinated patients received either mRNA vaccines (BNT162b2 or mRNA-1273) or adenoviral vector vaccines (ChAdOx1-S or Ad26.COV2). Incident rate ratios (IRRs) were computed from August 1, 2021, to January 31, 2022; ICU and baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU were analyzed from August 1 to December 15, 2021. EXPOSURES COVID-19 vaccination status (no vaccination, mRNA vaccine, adenoviral vector vaccine). MAIN OUTCOMES AND MEASURES The incidence IRR of ICU admission was evaluated, comparing vaccinated people with unvaccinated, adjusted for age and sex. The baseline characteristics at ICU admission of vaccinated and unvaccinated patients were investigated. The association between vaccination status at ICU admission and mortality at ICU and hospital discharge were also studied, adjusting for possible confounders. RESULTS Among the 10 107 674 inhabitants of Lombardy, Italy, at the time of this study, the median [IQR] agewas 48 [28-64] years and 5 154 914 (51.0%) were female. Of the 7 863 417 individuals who were vaccinated (median [IQR] age: 53 [33-68] years; 4 010 343 [51.4%] female), 6 251 417 (79.5%) received an mRNA vaccine, 550 439 (7.0%) received an adenoviral vector vaccine, and 1 061 561 (13.5%) received a mix of vaccines and 4 497 875 (57.2%) were boosted. Compared with unvaccinated people, IRR of individuals who received an mRNA vaccine within 120 days from the last dosewas 0.03 (95% CI, 0.03-0.04; P &lt;.001), whereas IRR of individuals who received an adenoviral vector vaccine after 120 days was 0.21 (95% CI, 0.19-0.24; P &lt;.001). There were 553 patients admitted to an ICU for COVID-19 pneumonia during the study period: 139 patients (25.1%) were vaccinated and 414 (74.9%) were unvaccinated. Compared with unvaccinated patients, vaccinated patients were older (median [IQR]: 72 [66-76] vs 60 [51-69] years; P &lt;.001), primarily male individuals (110 patients [ 79.1%] vs 252 patients [60.9%]; P &lt;.001), with more comorbidities (median [IQR]: 2 [1-3] vs 0 [0-1] comorbidities; P &lt;.001) and had higher ratio of arterial partial pressure of oxygen (PaO2) and fraction of inspiratory oxygen (FiO(2)) at ICU admission (median [IQR]: 138 [100-180] vs 120 [90-158] mm Hg; P =.007). Factors associated with ICU and hospital mortality were higher age, premorbid heart disease, lower PaO2/FiO(2) at ICU admission, and female sex (this factor only for ICU mortality). ICU and hospital mortality were similar between vaccinated and unvaccinated patients. CONCLUSIONS AND RELEVANCE In this cohort study, mRNA and adenoviral vector vaccines were associated with significantly lower risk of ICU admission for COVID-19 pneumonia. ICU and hospital mortality were not associated with vaccinated status.These findings suggest a substantial reduction of the risk of developing COVID-19-related severe acute respiratory failure requiring ICU admission among vaccinated people

Exploring Cosmic Origins with CORE: Cosmological Parameters

We forecast the main cosmological parameter constraints achievable with theCORE space mission which is dedicated to mapping the polarisation of the CosmicMicrowave Background (CMB). CORE was recently submitted in response to ESA'sfifth call for medium-sized mission proposals (M5). Here we report the resultsfrom our pre-submission study of the impact of various instrumental options, inparticular the telescope size and sensitivity level, and review the great,transformative potential of the mission as proposed. Specifically, we assessthe impact on a broad range of fundamental parameters of our Universe as afunction of the expected CMB characteristics, with other papers in the seriesfocusing on controlling astrophysical and instrumental residual systematics. Inthis paper, we assume that only a few central CORE frequency channels areusable for our purpose, all others being devoted to the cleaning ofastrophysical contaminants. On the theoretical side, we assume LCDM as ourgeneral framework and quantify the improvement provided by CORE over thecurrent constraints from the Planck 2015 release. We also study the jointsensitivity of CORE and of future Baryon Acoustic Oscillation and Large ScaleStructure experiments like DESI and Euclid. Specific constraints on the physicsof inflation are presented in another paper of the series. In addition to thesix parameters of the base LCDM, which describe the matter content of aspatially flat universe with adiabatic and scalar primordial fluctuations frominflation, we derive the precision achievable on parameters like thosedescribing curvature, neutrino physics, extra light relics, primordial heliumabundance, dark matter annihilation, recombination physics, variation offundamental constants, dark energy, modified gravity, reionization and cosmicbirefringence. (ABRIDGED

Probing the neutrino sector through Cosmic Microwave Background observations

Le interazioni tra neutrini oltre il modello standard della fisica delle particelle sono un campo aperto sia dal punto di vista teorico che sperimentale. In questa tesi presentiamo come le proprietà non standard dei neutrini possano essere vincolate usando le osservazioni cosmologiche e in particolare i dati della radiazione di fondo cosmica, come i dati di Planck. Considereremo la possibilità che i neutrini posseggano interazioni segrete scalari o pseudoscalari mediate da un bosone Nambu-Goldstone di una simmetria globale spontaneamente rotta U (1) ancora sconosciuta, come ad esempio i modelli che includono i Majoroni oppure quelle interazioni segrete di contatto tra neutrini sterili leggeri (∼ 1 eV), mediati da un bosone di gauge massivo X (con M X M W ). Presenteremo vincoli sulla forza di interazione e sulla massa di neutrini consentita dai dati cosmologici o in combinazione con osservazioni astrofisiche, infine discuteremo la fattibilità dei modelli considerati.Neutrino interactions beyond the standard model of particle physics are an open field both from theoretical and experimental point of view. In this thesis we present how non- standard neutrino properties can be constrained using cosmological observations and in particular cosmic microwave background data like those of the Planck satellites. We will consider the possibility that neutrinos possess secret scalar or pseudoscalar interactions mediated by the Nambu-Goldstone boson of a still unknown spontaneously broken global U (1) symmetry, as in, e.g., Majoron models or that secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson X (with M X M W ) exist. We will present constraints on the interaction strength and on the neutrino mass allowed by cosmological data alone or in combination with astrophysical observations and we will discuss the feasibility of the considered models