Browsing by Author "Rivera Vergara, Juan Cristóbal"

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    Cosmic ray tests for the QS1 module of the new small wheel in the ATLAS experiment -and- prospects on the search for heavy vector triplet bosons in the leptonic decay channels with the ATLAS experiment at the HL-LHC
    (2018) Rivera Vergara, Juan Cristóbal; Ochoa-Ricoux, Juan Pedro; Pontificia Universidad Católica de Chile. Facultad de Física
    The ATLAS detector at the LHC, CERN, will be upgraded after the current data taking period (Run 2). The ATLAS detector has to under go a series of upgrades in order to fulfill the needed performance at improved LHC conditions. The LHC will stop for the second time between 2019-2020, period of time during which the ATLAS detector is going to upgrade its muon subdetector. This upgrade is the New Small Wheel (NSW), which will replace part of it send cap muon spectrometer. The NSW will be comprised of two detection systems, the Micro Megas and the small-strip Thin Gap Chambers (sTGC), the latest is being constructed in Chile by a joint collaboration between PUC and UTFSM. After the construction, the chambers are tested before being shipped to CERN. The muon detection efficiency is calculated using cosmic muons. A trigger system is used as part of the setup, which checks for coincidences between plastic scintillator arrays placed on top and below the detectors in order to distinguish muons from background signals. A DAQ system is used to callibrate the electronics and measure muon hits. The whole system has been set up and has already been used to test one module that was successfully sent to CERN and integrated into the first wedge. Prospects were made for searches for new heavy SSM Z and W bosons at the last stage of the LHC (2024-2032), called High Luminosity LHC (HL-LHC), which is expected to run at √s = 14 TeV and collect 3000 fb−1 of data. These studies are based on MC simulations, and are used as benchmark for other models. The response of the upgraded ATLAS detector as well as pile-up collisions were simulated. SSM Z bosons are searched for in the dilepton final states, where it is expected to observe a signal with a more than five significance value at an invariant mass of 6.4 TeV, and exclude masses up to 6.5 TeV. SSMW0 bosons are searched for in the lepton plus neutrino final state, where itis expected to observe a signal with a more than five significance value at an invariant mass of 7.7 TeV, and exclude masses up to 7.9 TeV.
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    Measurement of long-range two-particle azimuthal correlations in Z-boson tagged pp collisions at s=8 and 13 TeV
    (2020) Aaboud, M.; Aad, G.; Abbott, B.; Abbott, D. C.; Abdinov, O.; Abeloos, B.; Abhayasinghe, D. K.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adam, L.; Adam Bourdarios, C.; Adamczyk, L.; Adamek, L.; Adelman, J.; Blunier, Sylvain; Díaz Gutiérrez, Marco Aurelio; Lee, Graham Richard; Ochoa-Ricoux, Juan Pedro; Olivares Pino, Sebastián Andrés; Rivera Vergara, Juan Cristóbal
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    Observation of electroweak W±Z boson pair production in association with two jets in pp collisions at TeV with the ATLAS detector
    (Elsevier B.V, 2019) Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Abeloos, B.; Abhayasinghe, D. K.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Adamczyk, L; Adelman, J.; Bourdarios, C. Adam ; Blunier, Sylvain; Díaz Gutiérrez, Marco Aurelio; Garay Walls, Francisca Montserrat; Lee Graham, Richard; Ochoa Ricoux, Juan Pedro; Olivares Pino, Sebastián Andrés; Rivera Vergara, Juan Cristóbal; The ATLAS Collaboration
    An observation of electroweak production in association with two jets in proton–proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of TeV are used, corresponding to an integrated luminosity of. Events containing three identified leptons, either electrons or muons, and two jets are selected. The electroweak production of bosons in association with two jets is measured with an observed significance of 5.3 standard deviations. A fiducial cross-section for electroweak production including interference effects and for a single leptonic decay mode is measured to be. Total and differential fiducial cross-sections of the sum of electroweak and strong productions for several kinematic observables are also measured.