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Unno, Y. et al, Garcia, C., Jimenez, J., Lacasta, C., Marti-Garcia, S., & Soldevila, U. (2014). Development of n(+) -in-p large-area silicon microstrip sensors for very high radiation environments-ATLAS12 design and initial results. Nucl. Instrum. Methods Phys. Res. A, 765, 80–90.
Abstract: We have been developing a novel radiation tolerant n(+)-in-p silicon microstrip sensor for very high radiation environments, aiming for application in the high luminosity large hadron collider. The sensors are fabricated in 6 in., p-type, float zone wafers, where large area strip sensor designs are laid out together with a number of miniature sensors. Radiation tolerance has been studied with ATLAS07 sensors and with independent structures. The ATLAS07 design was developed into new ATLAS12 designs. The ATLAS12A large-area sensor is made towards an axial strip sensor and the ATLAS12M towards a stereo strip sensor. New features to the ATLAS12 sensors are two dicing lines: standard edge space of 910 pm and slim edge space of 450 pm, a gated punch-through protection structure, and connection of orphan strips in a triangular corner of stereo strips. We report the design of the ATLAS12 layouts and initial measurements of the leakage current after dicing and the resistivity of the wafers.
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Alcaide, J., Chala, M., & Santamaria, A. (2018). LHC signals of radiatively-induced neutrino masses and implications for the Zee-Babu model. Phys. Lett. B, 779, 107–116.
Abstract: Contrary to the see-saw models, extended Higgs sectors leading to radiatively-induced neutrino masses do require the extra particles to be at the TeV scale. However, these new states have often exotic decays, to which experimental LHC searches performed so far, focused on scalars decaying into pairs of same-sign leptons, are not sensitive. In this paper we show that their experimental signatures can start to be tested with current LHC data if dedicated multi-region analyses correlating different observables are used. We also provide high-accuracy estimations of the complicated Standard Model backgrounds involved. For the case of the Zee-Babu model, we show that regions not yet constrained by neutrino data and low-energy experiments can be already probed, while most of the parameter space could be excluded at the 95% C.L. in a high-luminosity phase of the LHC.
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Gomez, M. E., Lola, S., Ruiz de Austri, R., & Shafi, Q. (2018). Confronting SUSY GUT With Dark Matter, Sparticle Spectroscopy and Muon (g – 2). Front. Physics, 6, 127–9pp.
Abstract: We explore the implications of LHC and cold dark matter searches for supersymmetric particle mass spectra in two different grand unified models with left-right symmetry, SO(10) and SU(4)(c) x SU(2)(L) x SU(2)(R) (4-2-2). We identify characteristic differences between the two scenarios, which imply distinct correlations between experimental measurements and the particular structure of the GUT group. The gauge structure of 4-2-2 enhances significantly the allowed parameter space as compared to SO(10), giving rise to a variety of coannihilation scenarios compatible with the LHC data, LSP dark matter and the ongoing muon g-2 experiment.
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LHCf Collaboration(Adriani, O. et al), Faus-Golfe, A., & Velasco, J. (2011). Measurement of zero degree single photon energy spectra for sqrt(s) = 7 TeV proton-proton collisions at LHC. Phys. Lett. B, 703(2), 128–134.
Abstract: In early 2010. the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton-proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurrence of pile-up events), the single photon spectra at root s = 7 TeV and pseudo-rapidity (eta) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this Letter. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra-high energy cosmic-ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2 TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2 TeV in the rapidity range 8.81 < eta < 8.99.
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Davidek, T., & Fiorini, L. (2020). Search for Lepton-Flavor-Violating Decays of Bosons With the ATLAS Detector. Front. Physics, 8, 149–13pp.
Abstract: The quest for lepton-flavor-violating processes at the LHC represents one of the key searches for new physics beyond the Standard Model. This review summarizes the direct searches for lepton-flavor-violating decays of heavy bosons with the ATLAS detector, using proton-proton collisions at the center-of-mass energy of 13 TeV.
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