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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. (2017). Measurement of the Drell-Yan triple-differential cross section in pp collisions at root s=8 TeV. J. High Energy Phys., 12(12), 059–80pp.
Abstract: This paper presents a measurement of the triple-differential cross section for the Drell-Yan process Z/gamma* -> l(+)l(-) where l is an electron or a muon. The measurement is performed for invariant masses of the lepton pairs, m(ll), between 46 and 200 GeV using a sample of 20.2 fb(-1) of pp collisions data at a centre-of-mass energy of root s = 8 TeV collected by the ATLAS detector at the LHC in 2012. The data are presented in bins of invariant mass, absolute dilepton rapidity, vertical bar y(ll)vertical bar, and the angular variable cos theta* between the outgoing lepton and the incoming quark in the Collins-Soper frame. The measurements are performed in the range vertical bar y(ll)vertical bar < 2.4 in the muon channel, and extended to vertical bar y(ll)vertical bar < 3.6 in the electron channel. The cross sections are used to determine the Z boson forward-backward asymmetry as a function of vertical bar y(ll)vertical bar and m(ll). The measurements achieve high-precision, below the percent level in the pole region, excluding the uncertainty in the integrated luminosity, and are in agreement with predictions. These precision data are sensitive to the parton distribution functions and the effective weak mixing angle.
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Peñuelas, A., & Pich, A. (2017). Flavour alignment in multi-Higgs-doublet models. J. High Energy Phys., 12(12), 084–34pp.
Abstract: Extended electroweak scalar sectors containing several doublet multiplets require flavour-aligned Yukawa matrices to prevent the appearance at tree level of unwanted flavour-changing neutral-current transitions. We analyse the misalignment induced by one-loop quantum corrections and explore possible generalizations of the alignment condition and their compatibility with current experimental constraints. The hypothesis of flavour alignment at a high scale turns out to be consistent with all known phenomenological tests.
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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. (2017). Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at root s=13 TeV with the ATLAS detector. J. High Energy Phys., 12(12), 085–56pp.
Abstract: A search for pair production of a scalar partner of the top quark in events with four or more jets plus missing transverse momentum is presented. An analysis of 36.1 fb(-1) of root s = 13 TeV proton-proton collisions collected using the ATLAS detector at the LHC yields no significant excess over the expected Standard Model background. To interpret the results a simplified supersymmetric model is used where the top squark is assumed to decay via (t) over tilde (1) -> t((*)) (chi) over tilde (0)(1) and (t) over tilde (1) -> b (chi) over tilde (+/-)(1) -> bW((*)) (chi) over tilde (0)(1), where (chi) over tilde (0)(1) ((chi) over tilde (+/-)(1) denotes the lightest neutralino (chargino). Exclusion limits are placed in terms of the top-squark and neutralino masses. Assuming a branching ratio of 100% to t (chi) over tilde (0)(1), top-squark masses in the range 450-1000 GeV are excluded for (chi) over tilde (0)(1) masses below 160 GeV. In the case where m((t) over tilde1) similar to m(t) + m((chi) over tilde 10), top-squark masses in the range 235-590 GeV are excluded.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2017). Measurement of the Y(nS) polarizations in pp collisions at root s=7 and 8 TeV. J. High Energy Phys., 12(12), 110–60pp.
Abstract: The polarization of the (sic) (1S), (sic) (2S) and (sic) (3S) mesons, produced in pp collisions at centre-of-mass energies root s = 7 and 8TeV, is measured using data samples collected by the LHCb experiment, corresponding to integrated luminosities of 1 and 2 fb(-1), respectively. The measurements are performed in three polarization frames, using (sic) -> μμdecays in the kinematic region of the transverse momentum p(T)((sic)) < 30 GeV/c and rapidity 2.2 < y((sic)) < 4.5. No large polarization is observed.
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Llanes Jurado, J., Rodrigo, G., & Torres Bobadilla, W. J. (2017). From Jacobi off-shell currents to integral relations. J. High Energy Phys., 12(12), 122–22pp.
Abstract: In this paper, we study off-shell currents built from the Jacobi identity of the kinematic numerators of gg -> X with X = ss, q (q) over bar, gg. We find that these currents can be schematically written in terms of three-point interaction Feynman rules. This representation allows for a straightforward understanding of the Colour-Kinematics duality as well as for the construction of the building blocks for the generation of higher-multiplicity tree-level and multi-loop numerators. We also provide one-loop integral relations through the Loop-Tree duality formalism with potential applications and advantages for the computation of relevant physical processes at the Large Hadron Collider. We illustrate these integral relations with the explicit examples of QCD one-loop numerators of gg -> ss.
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