LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Search for the lepton-flavour violating decays B-0 -> K*0 tau(+/-)mu -/+. J. High Energy Phys., 06(6), 143–25pp.
Abstract: A first search for the lepton-flavour violating decays B-0 -> K*0 tau(+/-)mu -/+ is presented. The analysis is performed using a sample of proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13TeV between 2011 and 2018, corresponding to an integrated luminosity of 9 fb(-1). No significant signal is observed, and upper limits on the branching fractions are determined to be B(B-0 -> K*0 tau(+)mu(-)) < 1.0 (1.2) x 10(-5) and B(B-0 -> K*0 tau(-)mu(+)) < 8.2 (9.8) x 10(-6) at the 90% (95%) confidence level.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Amplitude analysis of the D+-> pi(-)pi(+)pi(+) decay and measurement of the pi(-)pi(+) S-wave amplitude. J. High Energy Phys., 06(6), 044–28pp.
Abstract: An amplitude analysis of the D+-> (-)pi(+)pi(+) decay is performed with a sample corresponding to 1.5 fb(-1) of integrated luminosity of pp collisions at a centre-of-mass energy root s = 8 TeV collected by the LHCb detector in 2012. The sample contains approximately six hundred thousand candidates with a signal purity of 95%. The resonant structure is studied through a fit to the Dalitz plot where the pi(-)pi(+) S-wave amplitude is extracted as a function of pi(-)pi(+) mass, and spin-1 and spin-2 resonances are included coherently through an isobar model. The S-wave component is found to be dominant, followed by the rho(770)(0)pi(+) and f(2)(1270)pi(+) components. A small contribution from the omega(782) -> pi(-)pi(+) decay is seen for the first time in the D+-> pi(-)pi(+)pi(+) decay.
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ATLAS Collaboration(Aad, G. et al), Aparisi Pozo, J. A., Bailey, A. J., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2023). Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at root s=13 TeV with the ATLAS detector. J. High Energy Phys., 06(6), 019–56pp.
Abstract: A measurement of the top-quark mass (m(t)) in the t (t) over bar -> lepton+ jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass m(l mu) of the lepton, l (with l = e, mu), from the W-boson decay and the muon, mu, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb(-1) of root s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 +/- 0.39 (stat.) +/- 0.66 (syst.) +/- 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup.
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Giachino, A., van Hameren, A., & Ziarko, G. (2024). A new subtraction scheme at NLO exploiting the privilege of k<sub>T</sub>-factorization. J. High Energy Phys., 06(6), 167–39pp.
Abstract: We present a subtraction method for the calculation of real-radiation integrals at NLO in hybrid k(T)-factorization. The main difference with existing methods for collinear factorization is that we subtract the momentum recoil, occurring due to the mapping from an (n + 1)-particle phase space to an n-particle phase space, from the initial-state momenta, instead of distributing it over the final-state momenta.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2011). Search for massive long-lived highly ionising particles with the ATLAS detector at the LHC. Phys. Lett. B, 698(5), 353–370.
Abstract: A search is made for massive highly ionising particles with lifetimes in excess of 100 ns, with the ATLAS experiment at the Large Hadron Collider, using 3.1 pb(-1) of pp collision data taken at root s = 7 TeV. The signature of energy loss in the ATLAS inner detector and electromagnetic calorimeter is used. No such particles are found and limits on the production cross section for electric charges 6e <= vertical bar q vertical bar <= 17e and masses 200 GeV <= m <= 1000 GeV are set in the range 1-12 pb for different hypotheses on the production mechanism.
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