6062 research outputs found
Sort by
Dark ages, a window on the dark sector. Hunting for ultra-light axions
No full textMeasurements of 21 cm intensity mapping (IM) during the dark ages can potentially provide us with an unprecedented window on high redshifts and small scales.One of the main advantages this can bring involves the possibility to probe the nature of dark matter.Tests of dark matter models with the large-scale structure of the Universe are limited by non-linearities and astrophysical effects, which are not present for IM measurements during the dark ages.In this paper we focus on constraining the model in which dark matter is comprised, totally or in part, by ultra-light axion-like particles around the 10– 10 eV mass scale.For this model, the angular power spectrum of 21 cm brightness temperature fluctuations will exhibit a small-scale suppression.However, this effect is intertwined with the imprint of baryon-dark matter relative velocity at recombination, causing at the same time an enhancement at large-scales, which is affected by the mass and abundance of axion dark matter.In this work we forecast how future radio arrays will be able to constrain ultra-light axion mass through both these effects on the angular power spectrum
Sphaleron Rate of <math display="inline"><msub><mi>N</mi><mi>f</mi></msub><mo>=</mo><mn>2</mn><mo>+</mo><mn>1</mn></math> QCD
No full textWe compute the sphaleron rate of Nf=2+1 QCD at the physical point for a range of temperatures 200 MeV≲T≲600 MeV. We adopt a strategy recently applied in the quenched case, based on the extraction of the rate via a modified version of the Backus-Gilbert method from finite-lattice-spacing and finite-smoothing-radius Euclidean topological charge density correlators. The physical sphaleron rate is finally computed by performing a continuum limit at fixed physical smoothing radius, followed by a zero-smoothing extrapolation. Dynamical fermions were discretized using the staggered formulation, which is known to yield large lattice artifacts for the topological susceptibility. However, we find them to be rather mild for the sphaleron rate
Direct Detection of Dark Matter: A Critical Review
No full textThe nature of dark matter in the Universe is one of the hardest unsolved problems in modern physics. Indeed, on one hand, the overwhelming indirect evidence from astrophysics seems to leave no doubt about its existence; on the other hand, direct search experiments, especially those conducted with low-background detectors in underground laboratories all over the world, seem to deliver only null results with a few debated exceptions. Furthermore, the lack of predicted candidates on the LHC energy scale has made this dichotomy even more puzzling. We will recall the most important phases of this novel branch of experimental astro-particle physics, analyzing the interconnections among the main projects involved in this challenging quest, and we will draw conclusions slightly different from how the problem is commonly understood
Observation of <math display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mn>3</mn><mo stretchy="false">(</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>-</mo></msup><mo stretchy="false">)</mo></math>
No full textBy analyzing (27.12±0.14)×108 ψ(3686) events collected with the BESIII detector operating at the BEPCII collider, the decay processes χcJ→3(K+K-) (J=0, 1, 2) are observed for the first time with statistical significances of 8.2σ, 8.1σ, and 12.4σ, respectively. The product branching fractions of ψ(3686)→γχcJ, χcJ→3(K+K-) are presented and the branching fractions of χcJ→3(K+K-) decays are determined to be Bχc0→3(K+K-)=(10.7±1.8±1.1)×10-6, Bχc1→3(K+K-)=(4.2±0.9±0.5)×10-6, and Bχc2→3(K+K-)=(7.2±1.1±0.8)×10-6, where the first uncertainties are statistical and the second are systematic
Light dark matter search using a diamond cryogenic detector
No full textDiamond operated as a cryogenic calorimeter is an excellent target for direct detection of low-mass dark matter candidates. Following the realization of the first low-threshold cryogenic detector that uses diamond as absorber for astroparticle physics applications, we now present the resulting exclusion limits on the elastic spin-independent interaction cross-section of dark matter with diamond. We measured two 0.175 g CVD (Chemical Vapor Deposition) diamond samples, each instrumented with a Transition Edge Sensor made of Tungsten (W-TES). Thanks to the energy threshold of just 16.8 eV of one of the two detectors, we set exclusion limits on the elastic spin-independent interaction of dark matter particles with carbon nuclei down to dark matter masses as low as 0.122 GeV/c. This work shows the scientific potential of cryogenic detectors made from diamond and lays the foundation for the use of this material as target for direct detection dark matter experiments
Status of dual-readout calorimetry for future high-energy physics experiments
No full textFuture experiments at high energy ee colliders will focus on extremely precise Standard Model measurements. Among the most important physics benchmarks, there is the capability to resolve the Higgs decays into W or Z pairs, in their completely hadronic decay modes (4 jets in the final state), only based on the invariant mass of the jet pair coming from decay of the on-shell boson. This translates into a relative energy resolution target of 30%/√E, well beyond current detector performances. Dual-readout calorimetry is a technique which aims to improve the energy resolution, for single hadrons and hadronic jets, exploiting the information produced by two different physical processes, namely scintillation and Čerenkov light emission. The IDEA detector, whose concept has been included in both the FCC and CEPC Conceptual Design Reports, is based on a dual-readout fibre calorimeter with independent fibre readout exploiting Silicon PhotoMultipliers (SiPMs). The individual SiPM information will be beneficial for a highly granular calorimeter design, opening up to advanced reconstruction techniques such as Particle Flow and a variety of neural network algorithms.In this paper the status of calorimeter prototypes that have been developed to demonstrate the feasibility of the dual-readout method in association with the high granularity feature is illustrated. The specific choice for the design of each prototype is presented, together with the performances achieved at high-energy test beams or through simulations
Comprehensive constraints on heavy sterile neutrinos from core-collapse supernovae
No full textSterile neutrinos with masses up to O(100) MeV can be copiously produced in a supernova (SN) core through the mixing with active neutrinos. In this regard, the SN 1987A detection of neutrino events has been used to put constraints on active-sterile neutrino mixing, exploiting the well-known SN cooling argument. We refine the calculation of this limit including neutral current interactions with nucleons, which constitute the dominant channel for sterile neutrino production. We also include, for the first time, the charged current interactions between sterile neutrinos and muons, relevant for the production of sterile neutrinos mixed with muon neutrinos in the SN core. Using the recent modified luminosity criterion, we extend the bounds to the case where sterile states are trapped in the stellar core. Additionally, we study the decays of heavy sterile neutrinos, affecting the SN explosion energy and possibly producing a gamma-ray signal. We also illustrate the complementarity of our new bounds with cosmological bounds and laboratory searches
Scienza Aperta per l'accesso alla conoscenza
Get PDF<p>Intervento per il Convegno “La valutazione della ricerca alla prova dei fatti”, Firenze 2024.01.17</p>
Carta Geologica d'Italia alla scala 1:50.000, F. 184 Mirandola. Geologia di sottosuolo
No full text<p>Foglio geologico di sottosuolo alla scala 1:50.000 basato su rilevamenti alla scala 1:10.000 (eseguiti tra il 2021 e il 2023) comprensivo di legenda, schemi a cornice, sezioni geologiche.</p>
Dataset related to article \"Prism adaptation in patients with unilateral lesion of the parietal or cerebellar cortex: A pilot study on two single cases using a concurrent exposure procedure\
No full text<p>All dataset descriptive details available on the downloadable file.</p>