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Study of the modelling of W/Z + HF as background for V H(H → b¯b) at ATLAS
Get PDFThe Higgs boson properties has been measured at the ATLAS experiment since its discovery, obtaining a good agreement with the Standard Model predictions. Evidence of H → b¯b is crucial for constraining the overall Higgs boson decay width and to confirm the Yukawa coupling to quark sector. The most promising production mode is the V H, where the Higgs boson is in association with a vector boson. The vector boson decaying into leptons helps in the extraction of the signal from the multijet background which dominates the H → b¯b. One of the main sources of background for the Standard Model V H(H → b¯b) search is the production of V (V = W or Z) bosons in the association with jets. This contribution describes the ATLAS simulation setup used to model this irriducible background in proton-proton collisions at centre-of-mass energy of 13 TeV. Several Monte Carlo generators are studied in different phase-space regions and compared to unfolded data distribution, with additional requirements on the heavy-flavour content of the
associated jets
Measurements of the 3He and D components in cosmic rays with the AMS-02 experiment
Get PDFThe 3He/4He and D/p flux ratios in cosmic rays (CR) are two of the most valuable tools for understanding the propagation of CR in the galaxy and constrain the models that describe it. In this work, two new preliminary measurements of 3He/4He and D/p flux ratios are presented, each obtained from the data of the AMS-02 experiment
Study of the sensitivity of the SABRE experiment for direct Dark-Matter search
Get PDFThe orbital motion of the Earth around the Sun is expected to produce a modulation in the interaction rate of hypothetical dark-matter particles in an Earth-based detector. The DAMA experiment has observed a signal compatible with this modulation in the scintillation light of NaI(Tl) crystals with high statistical significance. This claim has not yet been verified since the other experiments involved in this type of research employ different target materials and technologies and can not be compared with DAMA independently of the assumed theoretical model. SABRE will provide a model-independent test of the DAMA claim through the use of ultrapure NaI(Tl) crystals (same target material as DAMA) and by studying the
modulation signal in both the hemispheres identifying any possible terrestrial contribution. To further reduce the background level the crystals will be placed in an active veto system. This paper presents the detector sensitivity studies in order to understand its ability to verify the DAMA claim
The phase II ATLAS Pixel: The Inner Tracker (ITk)
Get PDFThe ATLAS experiment is expected to enter the high-luminosity programme of the LHC (HL-LHC) with a thoroughly upgraded detector. This includes an all-silicon tracking system Inner Tracker (ITk) that will completely replace
the current Inner Detector. The innermost part of the ITk will consist of a five-layer pixel detector in the barrel region complemented by two end-caps characterized by
annular supports leading to an extended track reconstruction coverage. Different sensor technologies (planar, 3D and CMOS) are being investigated for instrumenting the detector, which will need to cope with the high occupancy and radiation level that are expected in the HL-LHC environment. For the same reason a new front-end
chip is being developed within the RD53 Collaboration. High data rates, expected in particular in the innermost layers, require the development of new technologies allowing high bandwidth transmission and handling
R&D for new silicon pixel sensors for the High Luminosity phase of the CMS experiment at LHC
Get PDFThe High Luminosity upgrade of the CERN LHC collider (HLLHC) demands a new high-radiation–tolerant solid-state pixel sensor capable of surviving fluencies up to a few 1016 neq/cm2 at ∼ 3 cm from the interaction point. To this extent the INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler (FBK), is aiming at the development of thin n-in-p–type pixel sensors for the HL-LHC. The R&D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100 μm and 130 μm active thickness for planar sensors, and 130 μm for 3D sensors, the thinnest ones ever produced so far. The first prototypes of hybrid modules, bump-bonded to the present CMS readout chip, have been tested on beam. The first results on their performance before and after irradiation are presented
Production and quality control of the new chambers with GEM technology in the CMS muon system
Get PDFThe CMS Collaboration has approved the installation of an additional set of muon detectors based on triple-GEM technology in the first endcap muon station known as GE1/1. The chambers are currently under construction and will be installed in 2019 during the second Long Shutdown (LS2) planned by LHC. About half of the required 144 chambers have been already built by different production sites in Europe, Asia and the United States. Systematic inspections and strict quality controls, scheduled for the GE1/1 chambers approval by the central site (CERN), were carried out successfully in Bari and Frascati (Italy). The results
of the quality control procedures concerning the effective gain and the response uniformity of the delivered detectors will be shown together with the results on other relevant parameters like internal pressure drop and maximum spurious signal rate
Laser calibration system for the Muon g − 2 Experiment at Fermilab
Get PDFMuon g − 2 experiment at Fermilab is going to measure the anomalous magnetic moment of the muon with a precision of 0.14 ppm like never before. This fourfold precision goal compared to the previous g − 2 experiment at BNL required improvements in all fronts, a big part of which will come from the gain correction of the SiPM-based calorimeters using a complex laser calibration system developed by INFN
Imaging detectors based on photoluminescence of radiation-induced defects in lithium fluoride for XFEL beam monitoring
Get PDFLithium fluoride (LiF) films and crystals are versatile X-ray imaging detectors based on the optical reading of visible photoluminescence from radiationinduced electronic defects. Distinctive features of these detectors are their high spatial resolution across a large field of view, wide dynamic range and insensitivity to ambient light. These peculiarities of LiF detectors appear to be promising for monitoring the spatial intensity distribution of ultra-short, ultra-high pulses of the EUV-X-ray Free Electron Laser (XFEL) and could be exploited for coherent
diffraction imaging experiments
Search for dark matter produced in association with a Higgs boson decaying to a pair of W bosons at CMS
Get PDFThe results of a search for dark matter produced in association with a Higgs boson are presented. The analysis is based on the data collected in 2016 at a center-of-mass energy of 13 TeV in proton-proton collisions with the CMS detector at the LHC, for a total integrated luminosity of 35.9 fb−1. A two-Higgs-doublet model and a baryonic Z model are used as benchmark. After the final selection, no
significant evidence for dark matter particle production has been observed. TwoHiggs-doublet-Z signals with a pseudoscalar mass up to 800 GeV are excluded at 95% of CL for a Z of mass between 1 TeV and 3 TeV. For the baryonic Z model, Z mediator masses up to 1.5 TeV and dark matter particle masses up to 420 GeV are excluded. The results are also reinterpreted in terms of spin-independent interaction cross-section between dark matter and nuclei, excluding values larger than 10−42 cm2 for light dark matter particles
Aree interne e beni culturali: il patrimonio dismesso in Costiera Amalfitana
Get PDFThe contribution intends to combine some themes that refer to the abandoned areas
and the need for recovery connected to them, to the internal areas and to the possible
economic revitalization processes, to the role of the cultural heritage for the creation
of tourist offers complementary to the seaside ones. To this end, the case of a
geographic context of great value is presented, which, however, is affected by the
presence of hilly and mountainous areas behind the sea belt where a range of cultural
assets is found that are not adequately valued. It is, in particular, a rich proto-industrial
heritage linked to ancient milling and paper production, which had characterized the
economy and the economic history of the area since the Middle Ages. The research
was carried out using a methodology based on census, location of disused structures,
analysis of the characteristics of each and realization of photographic and informative
documentation. The final result provides the framework of a cultural, material and
immaterial heritage, located in the internal area of the Costa that insists, abandoned,
on the territory