Publications by authors named "Fabbietti L"

The SIDDHARTA-2 collaboration has developed a novel X-ray detection system based on cadmium-zinc-telluride (CZT, CdZnTe), marking the first application of this technology at the DAΦNE electron-positron collider at INFN-LNF. This work aims to demonstrate the stability of the detectors' performance in terms of linearity and resolution over short and long periods, thereby establishing their suitability for precise spectroscopic measurements within a collider environment. A reference calibration spectrum is presented in association with findings from assessments of linearity and resolution stability.

View Article and Find Full Text PDF

Antinuclei in our Galaxy may stem either from annihilation or decay of dark matter, or from collisions of cosmic rays with the interstellar medium, which constitute the background of indirect dark matter searches. Understanding the formation mechanism of (anti)nuclei is crucial for setting limits on their production in space. Coalescence models, which describe the formation of light nuclei from final-state interaction of nucleons, have been widely employed in high-energy collisions.

View Article and Find Full Text PDF
Article Synopsis
  • The Letter reports the most accurate measurement so far of the matter-antimatter imbalance during Pb-Pb collisions at a high energy level of 5.02 TeV.
  • It utilizes the Statistical Hadronization framework to determine precise values for the electric charge and baryon chemical potentials, μ_{Q} and μ_{B}.
  • The analysis of antiparticle-to-particle yield ratios shows that the collisions create a system that is generally baryon-free and electrically neutral at midrapidity.
View Article and Find Full Text PDF

The ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum (high p_{T}) hadron trigger in proton-proton and central Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV. A data-driven statistical method is used to mitigate the large uncorrelated background in central Pb-Pb collisions.

View Article and Find Full Text PDF

K^{+}K^{-} pairs may be produced in photonuclear collisions, either from the decays of photoproduced ϕ(1020) mesons or directly as nonresonant K^{+}K^{-} pairs. Measurements of K^{+}K^{-} photoproduction probe the couplings between the ϕ(1020) and charged kaons with photons and nuclear targets. The kaon-proton scattering occurs at energies far above those available elsewhere.

View Article and Find Full Text PDF
Article Synopsis
  • - This Letter discusses the measurement of ridge yields from charged hadron angular correlations in proton-proton collisions at a high energy of 13 TeV, specifically within certain pseudorapidity and transverse momentum ranges.
  • - The research extends ridge yield measurements to low charged-particle multiplicity regions, where typically a strong interacting medium is not expected to form during collisions.
  • - Findings indicate that ridge yields in pp collisions are significantly higher than those observed in e^{+}e^{-} collisions, suggesting that processes in e^{+}e^{-} annihilations do not significantly influence long-range correlations in proton-proton interactions.
View Article and Find Full Text PDF
Article Synopsis
  • The ALICE detector measured the cross section for incoherent photonuclear production of J/ψ vector mesons, focusing on the Mandelstam |t| variable, during ultraperipheral collisions of Pb nuclei at a very high energy of 5.02 TeV.
  • The measurement was conducted within a rapidity interval of |y|<0.8 and covers a specific range of Bjorken-x values.
  • Analysis showed that models without quantum fluctuations in the gluon density predicted a much steeper |t|-dependence than observed, but including these fluctuations improved the models' alignment with the data.
View Article and Find Full Text PDF

The production of the ψ(2S) charmonium state was measured with ALICE in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (2.

View Article and Find Full Text PDF
Article Synopsis
  • Understanding how parton mass and Casimir color factors affect heavy quark emissions is key to studying quantum chromodynamics (QCD).
  • This research presents the first experimental constraint on the charm-quark splitting function, obtained through measurements in proton-proton collisions at 13 TeV.
  • Findings indicate that charm quarks show a steeper splitting function compared to gluons and light quarks, experiencing fewer emissions with a lower likelihood of large-angle emissions.
View Article and Find Full Text PDF

The most precise measurements to date of the _{Λ}^{3}H lifetime τ and Λ separation energy B_{Λ} are obtained using the data sample of Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV collected by ALICE at the LHC. The _{Λ}^{3}H is reconstructed via its charged two-body mesonic decay channel (_{Λ}^{3}H→^{3}He+π^{-} and the charge-conjugate process).

View Article and Find Full Text PDF
Article Synopsis
  • Kaonic atom X-ray spectroscopy helps explore the strong interactions between kaons and atomic nuclei/nucleons, using soft X-ray emissions (<20 keV) from light kaonic atoms like hydrogen and helium as well as ongoing research for harder X-ray emissions (>20 keV) from intermediate kaonic atoms like carbon and aluminum.
  • New experiments, particularly the SIDDHARTA-2 and EXCALIBUR proposals, focus on making precise measurements using advanced cadmium-zinc-telluride (CZT) detectors, which can effectively detect hard X-rays and gamma-rays.
  • A prototype CZT detector showed impressive performance at room temperature, achieving significant energy resolution in its measurements, and experiments conducted at the DAΦNE collider
View Article and Find Full Text PDF
Article Synopsis
  • * A notable negative correlation between the production of antiprotons and antideuterons was found across various collision centralities.
  • * Comparisons with theoretical models show that while a coalescence calculation explains certain statistical features, it struggles with the specifics of antiproton-antideuteron correlations, whereas thermal-statistical models can align with observations but imply different correlation volumes.
View Article and Find Full Text PDF

The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13  TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5  GeV/c) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions, and the jet signal is obtained as the difference between the toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the transverse region, which is dominated by the UE.

View Article and Find Full Text PDF

We study the polarization of inclusive J/ψ produced in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC in the dimuon channel, via the measurement of the angular distribution of its decay products. We perform the study in the rapidity region 2.

View Article and Find Full Text PDF

The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of _{Λ}^{3}H in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV is presented in this Letter.

View Article and Find Full Text PDF

The polarization of the Λ and Λ[over ¯] hyperons along the beam (z) direction, P_{z}, has been measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded with ALICE at the Large Hadron Collider (LHC). The main contribution to P_{z} comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient P_{z,s2}=⟨P_{z}sin(2φ-2Ψ_{2})⟩, where φ is the hyperon azimuthal emission angle and Ψ_{2} is the elliptic flow plane angle.

View Article and Find Full Text PDF
Article Synopsis
  • This article discusses the analysis of groomed jet substructure in proton-proton (pp) and lead-lead (Pb-Pb) collisions using the ALICE detector at a collision energy of 5.02 TeV.
  • The study employs a soft drop grooming algorithm to isolate hard parton splittings and measures the groomed jet momentum splitting fraction and radius, revealing distinct behavior in jet structure under different collision conditions.
  • Notably, a narrowing of the groomed jet radius distribution in Pb-Pb collisions suggests changes in jet angular structure due to quark-gluon plasma, while no significant differences are observed in momentum splitting fractions, contributing valuable insights into jet energy-loss mechanisms.
View Article and Find Full Text PDF

The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13  TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions.

View Article and Find Full Text PDF

The p_{T}-differential cross sections of prompt charm-strange baryons Ξ_{c}^{0} and Ξ_{c}^{+} were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy sqrt[s]=13  TeV with the ALICE detector at the LHC. The Ξ_{c}^{0} baryon was reconstructed via both the semileptonic decay (Ξ^{-}e^{+}ν_{e}) and the hadronic decay (Ξ^{-}π^{+}) channels.

View Article and Find Full Text PDF

The prompt production of the charm baryon Λ_{c}^{+} and the Λ_{c}^{+}/D^{0} production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. These new measurements show a clear decrease of the Λ_{c}^{+}/D^{0} ratio with increasing transverse momentum (p_{T}) in both collision systems in the range 2 View Article and Find Full Text PDF

This Letter presents the first experimental evidence of the attractive strong interaction between a proton and a ϕ meson. The result is obtained from two-particle correlations of combined p-ϕ⊕ p[over ¯]-ϕ pairs measured in high-multiplicity pp collisions at sqrt[s]=13  TeV by the ALICE Collaboration. The spin-averaged scattering length and effective range of the p-ϕ interaction are extracted from the fully corrected correlation function employing the Lednický-Lyuboshits approach.

View Article and Find Full Text PDF

The event-by-event correlations between three flow amplitudes are measured for the first time in Pb-Pb collisions, using higher-order symmetric cumulants. We find that different three-harmonic correlations develop during the collective evolution of the medium when compared to correlations that exist in the initial state. These new results cannot be interpreted in terms of previous lower-order flow measurements since contributions from two-harmonic correlations are explicitly removed in the new observables.

View Article and Find Full Text PDF

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC.

View Article and Find Full Text PDF

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC.

View Article and Find Full Text PDF

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4  GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles.

View Article and Find Full Text PDF