Bayar, M., Pavao, R., Sakai, S., & Oset, E. (2018). Role of the triangle singularity in Lambda(1405) production in the pi(-) p -> K-0 pi Sigma and pp -> pK(+) pi Sigma processes. Phys. Rev. C, 97(3), 035203–12pp.
Abstract: We have investigated the cross section for the pi(-) p -> K-0 pi Sigma and pp -> pK(+) pi Sigma reactions, paying attention to a mechanism that develops a triangle singularity. The triangle diagram is realized by the decay of a N* to K* Sigma and the K* decay into pi K, and the pi Sigma finally merges into Lambda (1405). The mechanism is expected to produce a peak around 2140 MeV in the K Lambda (1405) invariant mass. We found that a clear peak appears around 2100 MeV in the K Lambda (1405) invariant mass, which is about 40 MeV lower than the expectation, and that is due to the resonance peak of a N* resonance which plays a crucial role in the K* Sigma production. The mechanism studied produces the peak of the Lambda (1405) around or below 1400 MeV, as is seen in the pp -> pK(+) pi Sigma HADES experiment.
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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). Measurement of differential cross-sections of a single top quark produced in association with a W boson at root s=13 TeV with ATLAS. Eur. Phys. J. C, 78(3), 186–29pp.
Abstract: The differential cross-section for the production of a W boson in association with a top quark is measured for several particle-level observables. The measurements are performed using 36.1 fb(-1) of pp collision data collected with the ATLAS detector at the LHC in 2015 and 2016. Differential cross-sections are measured in a fiducial phase space defined by the presence of two charged leptons and exactly one jet matched to a b-hadron, and are normalised with the fiducial cross-section. Results are found to be in good agreement with predictions from several Monte Carlo event generators.
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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). Searches for heavy ZZ and ZW resonances in the llqq and vvqq final states in pp collisions at root s=13 TeV with the ATLAS detector. J. High Energy Phys., 03(3), 009–53pp.
Abstract: This paper reports searches for heavy resonances decaying into ZZ or ZW using data from proton-proton collisions at a centre-of-mass energy of root s – 13 TeV. The data, corresponding to an integrated luminosity of 36.1 fb(-1), were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The searches are performed in final states in which one Z boson decays into either a pair of light charged leptons (electrons and muons) or a pair of neutrinos, and the associated W boson or the other Z boson decays hadronically. No evidence of the production of heavy resonances is observed. Upper bounds on the production cross sections of heavy resonances times their decay branching ratios to ZZ or ZW are derived in the mass range 300-5000 GeV within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions. Production through gluon-gluon fusion, Drell-Yan or vector-boson fusion are considered, depending on the assumed model.
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Dai, L. R., Dias, J. M., & Oset, E. (2018). Disclosing D* (D)over bar* molecular states in the B-c(-) -> pi(-) J/psi omega decay. Eur. Phys. J. C, 78(3), 210–7pp.
Abstract: We study the B-c(-) -> pi(-) J/omega and B-c(-) -> pi(-) D* (D) over bar* reactions and show that they are related by the presence of two resonances, the X(3940) and X(3930), that are of molecular nature and couple most strongly to D* (D) over bar*, but also to J/psi omega. Because of that, in the J/psi omega mass distribution we find a cusp with large strength at the D* (D) over bar* threshold and predict the ratio of strengths between the peak of the cusp and the maximum of the D* (D) over bar* distribution close to D* (D) over bar* threshold, which are distinct features of the molecular nature of these two resonances.
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Bertone, G., Bozorgnia, N., Kim, J. S., Liem, S., McCabe, C., Otten, S., et al. (2018). Identifying WIMP dark matter from particle and astroparticle data. J. Cosmol. Astropart. Phys., 03(3), 026–42pp.
Abstract: One of the most promising strategies to identify the nature of dark matter consists in the search for new particles at accelerators and with so-called direct detection experiments. Working within the framework of simplified models, and making use of machine learning tools to speed up statistical inference, we address the question of what we can learn about dark matter from a detection at the LHC and a forthcoming direct detection experiment. We show that with a combination of accelerator and direct detection data, it is possible to identify newly discovered particles as dark matter, by reconstructing their relic density assuming they are weakly interacting massive particles (WIMPs) thermally produced in the early Universe, and demonstrating that it is consistent with the measured dark matter abundance. An inconsistency between these two quantities would instead point either towards additional physics in the dark sector, or towards a non-standard cosmology, with a thermal history substantially different from that of the standard cosmological model.
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