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Results on QGP by ATLAS and CMS
Get PDFQuantum chromodynamics (QCD) on the lattice predicts that at
high temperatures and energy densities, hadronic matter undergoes a phase transition and turns into a state of deconfined quarks and gluons known as quark-gluon plasma (QGP). This state of matter is typically thought to be created in the collisions of two heavy nuclei at ultrarelativistic energies, like the ones reached at the
LHC. Despite the multiyear effort, much remains to be learned about parton densities in nuclei, the search for the possible onset of parton saturation, how the properties of QGP emerge at a microscopic level from the interactions among the individual partons and how subsequently vary across its phase diagram. The ATLAS and CMS Collaborations fully exploit the opportunities offered by high-density QCD studies with ion and proton beams that allow the study of cold nuclear matter effects, the onset of nuclear saturation, and long-range correlations. Additionally, experiments put emphasis on the examination of hadrons at high transverse momentum, fully reconstructed jets, heavy quarkonia, open heavy flavor particles, and jet quenching.
Altogether, measurements at varying length scales provide quantitative information about the strongly coupled QGP, complementing the bulk and collective observables of the soft sector
Partial-wave analysis of τ−→π−π−π+ντ at BELLE
Get PDFWe present preliminary results of a partial-wave analysis of τ − → π−π−π+ντ in data from the Belle experiment at the KEKB e+e− collider. We demonstrate the presence of the a1(1420) and a1(1640) resonances in tauon decays and measure their masses and widths. We also present validation of our findings using a model-independent approach. Our results can improve modeling in simulation studies necessary for measuring the tauon electric and magnetic dipole moments and Michel parameters
New results on conventional heavy baryons from CMS
Get PDFThe present report summarizes recent CMS results in conventional and exotic hadron spectroscopy, obtained using the data collected at the Large Hadron Collider during the Run-2 data taking (2015–2018) with protonproton collisions at √s = 13 TeV. The results include the first observation of the Λ0b → J/ψΞ−K+ decay mode and the observation of Λ∗∗
b and Ξ∗∗b excited states
Light QCD exotics at BESIII
Get PDFUsing the world’s largest samples of J/ψ and ψ(3686) events produced in e+e− annihilation, BESIII is uniquely positioned to study light hadrons in radiative and hadronic charmonium decays. In particular, exotic hadron candidates including multiquark states, hybrid mesons and glueballs can be studied in high detail. Recent highlights on the light exotics searches, including the observation of an isoscalar spin-exotic 1−+ state η1(1855) in J/ψ → γηη, the observation of X(2600) in J/ψ → γπ+π−η and a PWA of J/ψ → γK0 SK0 Sπ0 are presented
Spin-1 quarkonia in a rotating frame and their spin contents
Get PDFWe propose a new way of studying the spin content of a hadron
by looking at its response in a rotating frame. By collecting all responses of quarks and gluons in a rotating frame, we describe the spin-rotation coupling of spin-1 quarkonia and thereby reveal their spin contents in a relativistic formalism
Dimuon trigger characterization for the study of the multiquark candidate at LHC Run 3 with the CMS experiment
Get PDFThe analysis of the B0 → X(3872)K0 S production channel of the tetraquark candidate X(3872), performed on CMS data acquired during LHC Run 3, is here presented. We characterised the performance of the new low-pT dimuon
trigger configuration implemented in Run 3 used for the analysis and estimated its impact on signal selection efficiency, which suggests a significant improvement with
respect to Run 2 triggers. Finally, preliminary results on the control channel are presented, showing good agreement between data and Monte Carlo and resulting in a branching ratio measurement compatible with the world average. The present analysis has yet to be fully validated by the CMS Collaboration, therefore only preliminary results will be presented
Ariel Space Telescope: Innovation for the new optics
Get PDFAtmospheric Remote-Sensing Infrared Exoplanet Large-survey (Ariel) is a visible/infrared mission funded by the European Space Agency. It will be launched in 2029 and will aim to observe a target of ∼1000 exoplanets to study their atmospheres in chemical composition and ephemeris. Ariel will be the first space mission designed specifically for this purpose. The intervention aims to give an overview of the space project; in particular, the Italian contribution to the realization of the telescope will be emphasized. The telescope will be an off-axis Cassegrain with an elliptical-shaped parabolic primary mirror of considerable size (1.1 × 0.7m optical area) entirely made of bare aluminum. Today, an aluminum mirror of this size (mainly for its major axis) has never been created for infrared observations. For this reason, the Italian team, supported by the industry, has planned a development, qualification, and validation campaign for a series of manufacturing processes for these optics. In particular, it will illustrate how the development of heat treatment, diamond turning, polishing, and coating were addressed to obtain large-sized polished aluminum optics
Status of the MEG II experiment: Searching for cLFV
Get PDFWe report the first results of the MEG II experiment on the search for the μ → eγ decay using the dataset collected in 2021. No evidence for this decay has been found: an upper limit on the branching ratio has been set to B(μ+ → e+γ) < 7.5 ×10−13 (90% CL). Combination of this result with the previous limit set by MEG experiment yields the most stringent limit on this charged lepton flavor violating decay: B(μ → eγ) < 3.1×10−13 (90% CL)
Investigating the effects of sample-substrate interaction in the Raman and photoluminescence spectrum of 1L-WS2
Get PDFWe carried out a spectroscopic investigation on monolayer (1L) crystals of WS2 deposited on different substrates, namely PDMS, silica, gold, hBN, and diamond, by Raman and photoluminescence measurements. Two spectral features were identified, which assess the degree of strain and doping transferred to the 1LWS2 flake by the substrate. The first one is the frequency of the E1 2g(Γ) peak in the Raman spectrum, whose blueshift is associated with an increase in the tensile strain applied to the 1L-WS2 crystal. The second one is the intensity ratio of the trion to exciton band in the photoluminescence spectrum, related to the density of electrons in excess from doping levels. A comparative analysis of the 1L-WS2 spectra collected on the different substrates reveals that the flakes deposited on diamond are those displaying a higher degree of strain and doping, possibly due to the large presence of C dangling bonds. Our results represent a valuable reference for high-pressure
optical measurements on low-dimensional transition metal dichalcogenides, in which 1L flakes are commonly exfoliated on the culet of Diamond Anvil Cells
Comparison of SiPMs and PMTs for calorimetry applications in the DUNE near detector complex
Get PDFThe KLOE electromagnetic calorimeter, selected for reuse in the DUNE experiment, has been under investigation for the potential replacement of traditional Photomultiplier Tubes (PMTs) with Silicon Photomultipliers (SiPMs). In this study, a segment of the KLOE lead-scintillating fiber calorimeter was equipped with SiPM arrays on one side and conventional PMTs on the other side. The efficiency and timing resolution of SiPMs are evaluated and compared with KLOEPMTs. The findings contribute to determining the feasibility of substituting PMTs with SiPMs