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Search for boosted H → b¯b decays in association with a jet using pp collisions collected by the ATLAS detector
No full textThe H → b¯b channel has been studied to perform precision measurement of a Standard Model Higgs boson and to probe New Physics. It has been recently proposed to use events where the Higgs boson is produced in association with a high-pT jet, achieving more sensitivity for b-tagged jets from the Higgs decay. In this work the latest ATLAS results will be shown about the search for 13 TeV events with a boosted Higgs decaying to b-pairs associated with a high-pT jet
Measurement of ttH production cross section times branching ratio in the γγ decay channel with the full Run2 pp collision dataset collected by the ATLAS experiment at √s = 13 TeV
No full textIn this study, the measurement of Higgs boson production in association with a top quark-antiquark pair in the two photons decay channel is presented. The analysis is based on 139 fb−1 of proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider at center-of-mass energy of √s = 13 TeV. The analysis is performed using a simultaneous fit in seven signalenriched event categories. The ttH¯ process is observed in the diphoton decay channel with a significance of 4.9σ relative to the background-only hypothesis, while the expected significance is 4.2σ. The ttH¯ cross-section times the H → γγ branching ratio is measured to be σttH¯ ×Bγγ = 1.59+0.43 −0.39 fb, in agreement with the Standard Model
prediction
First QUAX galactic axions search with a SC resonant cavity
No full textQuax is an axion haloscope that can search for axions by means of either their coupling with electron spins or with photons, making use of superconducting resonant cavities. A superconducting NbTi cavity was characterized at T = 4 K in a magnetic field. The cavity exhibited a quality factor of Q0 = 4.5 × 105 for the TM010 mode at 9 GHz in a 2 T magnetic field. Since the results were satisfactory, this cavity was also operated in a set-up to measure the axion coupling with photons, gaγγ. This resulted in an upper limit of gaγγ < 1.03 × 10−14 GeV−1 for an axion mass of about 37 μ eV
Constraining the Higgs boson self-coupling with single-Higgs and double-Higgs production measurements
No full textOne of the most important targets of the LHC is to improve the experimental results of the Run 1 and the complete exploration of the properties of the Higgs boson, in particular the Higgs boson self-coupling. The self-coupling, λHHH, is very loosely constrained by electroweak (EW) precision measurements, therefore new physics (NP) effects could induce large deviations from its Standard
Model (SM) expectation. Constraints on κλ, defined as the ratio κλ = λHHH/λSM HHH, are set using up to 80 fb−1 of LHC pp collision data at √s = 13 TeV collected with the ATLAS experiment. Single-Higgs results exploit the combination of the analyses targeting the γγ, ZZ∗, WW∗, τ +τ − and b¯b decay channels and use both inclusive and differential information, while double-Higgs results exploit the combination of the analyses targeting the b¯bγγ, b¯bτ +τ − and b¯bb¯b decay channels. From singleHiggs measurements, values outside the interval −3.2 < κλ < 11.9 are excluded at the 95% confidence level (CL) under the assumption that NP affects only the Higgs self-coupling. This interval is comparable to the one obtained from double-Higgs measurements, i.e., −5.0 < κλ < 11.9
Ultra-Fast Silicon Detectors for CMS Phase II upgrade
No full textThe Minimimum Ionizing Particle Timing Layer (MTD), proposed for the CMS Phase II upgrade at the High Luminosity LHC, will be provided with Ultra-Fast Silicon Detectors (UFSD), that will be covering an area of ∼ 15 m2 in the pseudorapidity region 1.5 < |η| < 3. MTD has the aim of adding timing information to reconstructed tracks with a precision of ∼ 30 ps: UFSD are the suited technology to reach the goal. In this work, the improvements in the development of such large area detector are presented, highlighting the current status and the R&D process towards the final design
Measurements of the relative alignment of the muon spectrometer precision chambers in √s = 13 TeV proton-proton collisions with the ATLAS detector
No full textA good muon momentum resolution in the region from hundreds of GeV to several TeV is crucial for searches for new physics, such as W → μν and Z → μμ (ATLAS Collaboration, Phys. Lett. B, 796 (2019) 68) at the LHC. A new physics signal in one of these channels could manifest itself as an excess over the Standard Model (SM) prediction in the form of a handful of muon candidates in the high-end tail of the transverse mass or invariant mass distribution. It is therefore important to reject poorly measured muons, where the reconstructed pT is much higher than the true value, to avoid the contamination of the highmass region with events migrating from lower masses. The ability to reconstruct high-momentum muon tracks in ATLAS with good momentum resolution is closely connected to a good understanding of the ATLAS tracking detectors alignment and of the related uncertainties. This contribution provides an overview of the method used in muon reconstruction to account for the differences in position and orientation of the various detector elements, between the geometry used in simulation and the real position of the detector
New direct measurement of the 6Li(p, γ)7Be cross-section at LUNA
No full text6Li+p fusion reactions take part in primordial nucleosynthesis and in the early stages of stellar evolution, prior to the main sequence. While the 6Li(p,α)
3He cross-section is relatively well known, the 6Li(p,γ)
7Be reaction is much debated, especially since a recent observation of a broad resonance at center-of-mass energy of 195 keV. Such resonance would correspond to an excited state of 7Be which has neither been observed before, nor supported by theoretical models. In order to verify the existence of such resonance, a new study of the 6Li(p,γ)
7Be and 6Li(p,α) 3He reactions was performed by the LUNA Collaboration at Gran Sasso National Laboratories. The present work provides an overview of the LUNA experiment and a description of the setup and measurement strategy adopted for the 6Li+p experimental campaign
Preliminary investigation of performance of thermoluminescent dosimeters for dose verification in brachytherapy
No full textBrachytherapy represents the treatment of choice for many cancerous lesions, including skin tumours. Purpose of the study was to investigate the performance of thermoluminescent dosimeters of type 100, (TLD-100), for dose verification in high dose-rate treatment with a radioactive source of iridium-192. A set of TLDs-100 was calibrated with a 250 kVp X-ray beam in the dose range 0–5 Gy. Through a head and neck phantom, TLDs were fixed on districts corresponding to volumes of interest, including the target volume and some critical structures, then a single fraction of brachytherapy treatment was delivered. The dose measurements provided by TLDs were compared with the planned ones and the results were discussed in the light of limitations affecting the current treatment planning systems and critical aspects relating to brachytherapy implementation that still occurred in
clinical settings. The findings of the study allow us to conclude that TLDs-100 show a good performance in the radiation field investigated and the use of so small, cheap and practical dosimetry system is potentially an optimal strategy of improving and standardizing the quality assurance protocol in brachytherap
Enfermedades, epidemias y pandemias en el videojuego histórico
Get PDFThe video game, as a channel of expression of cultural leisure, is also a reflection of the events we are experiencing. Many of its productions are based on historical events that allow the recreation of past events, but that go beyond the entertainment phenomenon to become a means of disseminating what happened.
The Middle Ages is one of the preferred periods for video game developers to
produce their productions, and the Black Death is one of the best-known references from that period. The study analyses not only how disease and epidemics were represented in the field of videogames during the Middle Ages, but also aims to state that this is one of the main factors that will determine a type of historical memory in the average user. The role of the historian is therefore fundamental as a guide so that this iconography of the past is not distorted or altered
Cutaneous Manifestations in Four Patients with COVID-19
Get PDFAs the numbers of SARS-CoV-2 infections increased globally, reports of cutaneous manifestations started to emerge. We describe several patients with COVID-19 who presented with skin changes. We noted such manifestations in four out of 110 patients (3.63%) and describe the clinical situation of each of these patients. Each patient had either a maculopapular or a urticariform rash. These manifestations have a broad differential diagnosis and it was difficult to exclude drug reactions. We hope to raise awareness of this possible manifestation of COVID-19 in order to raise suspicion of this diagnosis among clinicians when they encounter patients with fever and rash. Larger series that also include patients with mild disease and skin biopsies may be useful