ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2018). Search for long-lived, massive particles in events with displaced vertices and mlissing transverse momentum in root S=13 TeV pp collisions with the ATLAS detector. Phys. Rev. D, 97(5), 052012–29pp.
Abstract: A search for long-lived, massive particles predicted by many theories beyond the Standard Model is presented. The search targets final states with large missing transverse momentum and at least one highmass displaced vertex with five or more tracks, and uses 32.8 fb(-1) of root s = 13 TeV pp collision data collected by the ATLAS detector at the LHC. The observed yield is consistent with the expected background. The results are used to extract 95% C.L. exclusion limits on the production of long-lived gluinos with masses up to 2.37 TeV and lifetimes of O(10(-2)) – O(10) ns in a simplified model inspired by split supersymmetry.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2020). Search for Magnetic Monopoles and Stable High-Electric-Charge Objects in 13 Tev Proton-Proton Collisions with the ATLAS Detector. Phys. Rev. Lett., 124(3), 031802–20pp.
Abstract: A search for magnetic monopoles and high-electric-charge objects is presented using 34.4 fb(-1) of 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015 and 2016. The considered signature is based upon high ionization in the transition radiation tracker of the inner detector associated with a pencil-shape energy deposit in the electromagnetic calorimeter. The data were collected by a dedicated trigger based on the tracker high-threshold hit capability. The results are interpreted in models of Drell-Yan pair production of stable particles with two spin hypotheses (0 and 1/2) and masses ranging from 200 to 4000 GeV. The search improves by approximately a factor of 5 the constraints on the direct production of magnetic monopoles carrying one or two Dirac magnetic charges and stable objects with electric charge in the range 20 <= vertical bar z vertical bar <= 60 and extends the charge range to 60 < vertical bar z vertical bar <= 100.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2018). A search for pair-produced resonances in four-jet final states at root s=13 TeV with the ATLAS detector. Eur. Phys. J. C, 78(3), 250–28pp.
Abstract: A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb(-1) of root s = 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, (t) over tilde, which decays promptly into two quarks through R-parity-violating couplings. Top squarks with masses in the range 100 GeV < m((T) over tilde) < 410 GeV are excluded at 95% confidence level. If the decay is into a b-quark and a light quark, a dedicated selection requiring two b-tags is used to exclude masses in the ranges 100 GeV < m((t) over tilde) < 470 GeV and 480 GeV < m(<(t)over tilde>) < 610 GeV. Additional limits are set on the pair-production of massive colour-octet resonances.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2018). Search for heavy resonances decaying into WW in the e nu μnu final state in pp collisions at root s=13 TeV with the ATLAS detector. Eur. Phys. J. C, 78(1), 24–34pp.
Abstract: A search for neutral heavy resonances is performed in the WW -> e nu μnu decay channel using pp collision data corresponding to an integrated luminosity of 36.1 fb(-1), collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. No evidence of such heavy resonances is found. In the search for production via the quark-antiquark annihilation or gluon-gluon fusion process, upper limits on sigma(X) x B(X -> WW) as a function of the resonance mass are obtained in the mass range between 200 GeV and up to 5 TeV for various benchmark models: a Higgs-like scalar in different width scenarios, a two-Higgs-doublet model, a heavy vector triplet model, and a warped extra dimensions model. In the vector-boson fusion process, constraints are also obtained on these resonances, as well as on a Higgs boson in the Georgi-Machacek model and a heavy tensor particle coupling only to gauge bosons.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2016). Search for Minimal Supersymmetric Standard Model Higgs bosons H/A and for a Z ' boson in the tau tau final state produced in pp collisions at root s=13 TeV with the ATLAS Detector. Eur. Phys. J. C, 76(11), 585–30pp.
Abstract: A search for neutral Higgs bosons of the minimal supersymmetric standard model (MSSM) and for a heavneutral Z' boson is performed using a data sample corresponding to an integrated luminosity of 3.2 fb(-1) from proton-proton collisions at root s = 13 TeV recorded by the ATLAS detector at the LHC. The heavy resonance is assumed to decay to a tau(+)tau(-) pair with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-1.2 TeV for the MSSM neutral Higgs bosons and 0.5-2.5 TeV for the heavy neutral Z' boson. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in MSSMand Z' benchmark scenarios. The most stringent constraints on the MSSM m(A)-tan beta space exclude at 95% confidence level (CL) tan beta > 7.6 for m(A) = 200 GeV in the m(h)(mod+) MSSM scenario. For the Sequential Standard Model, a Z(SSM)' mass up to 1.90 TeV is excluded at 95% CL and masses up to 1.82-2.17 TeV are excluded for a Z(SFM)' of the strong flavour model.
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