Top pair invariant mass distribution: a window on new physics

Frederix, Rikkert; Maltoni, Fabio

doi:10.1088/1126-6708/2009/01/047

Cited by 170 publications

(198 citation statements)

References 87 publications

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“…We note that new techniques have recently been developed that reconstruct top-quarks produced with large enough transverse momentum such that their decay products can be tagged as a single jet [51][52][53][54]; however employing these methods is beyond the scope of our simple analysis here. We estimate the combined uncertainties in the NLO tt cross section and the parton distribution functions at high invariant masses to be of order 50% [55,56].…”

Section: Top-anti-top Resonancesmentioning

confidence: 99%

LHC predictions from a tevatron anomaly in the top quark forward-backward asymmetry

Bai

Hewett

Kaplan

et al. 2011

J. High Energ. Phys.

112

111

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Abstract:We examine the implications of the recent CDF measurement of the top-quark forward-backward asymmetry, focusing on a scenario with a new color octet vector boson at 1-3 TeV. We study several models, as well as a general effective field theory, and determine the parameter space which provides the best simultaneous fit to the CDF asymmetry, the Tevatron top pair production cross section, and the exclusion regions from LHC dijet resonance and contact interaction searches. Flavor constraints on these models are more subtle and less severe than the literature indicates. We find a large region of allowed parameter space at high axigluon mass and a smaller region at low mass; we match the latter to an SU(3) 1 × SU(3) 2 /SU(3) c coset model with a heavy vector-like fermion. Our scenario produces discoverable effects at the LHC with only 1 − 2 fb −1 of luminosity at √ s = 7 − 8 TeV. Lastly, we point out that a Tevatron measurement of the b-quark forwardbackward asymmetry would be very helpful in characterizing the physics underlying the top-quark asymmetry.

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Section: Top-anti-top Resonancesmentioning

confidence: 99%

LHC predictions from a tevatron anomaly in the top quark forward-backward asymmetry

Bai

Hewett

Kaplan

et al. 2011

J. High Energ. Phys.

112

111

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show abstract

“…[21,22] and in more detail in refs. [23][24][25][26]. It appears to receive similar QCD corrections, as indicated by estimates in an effective field theory (EFT) approach in the soft gluon approximation [27], and in a simplified K-factor derived from the geometric mean of the background and signal K-factors [28].…”

Section: Jhep10(2017)096mentioning

confidence: 76%

Scalar production and decay to top quarks including interference effects at NLO in QCD in an EFT approach

Franzosi

Vryonidou

Zhang

2017

J. High Energ. Phys.

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Scalar and pseudo-scalar resonances decaying to top quarks are common predictions in several scenarios beyond the standard model (SM) and are extensively searched for by LHC experiments. Challenges on the experimental side require optimising the strategy based on accurate predictions. Firstly, QCD corrections are known to be large both for the SM QCD background and for the pure signal scalar production. Secondly, leading order and approximate next-to-leading order (NLO) calculations indicate that the interference between signal and background is large and drastically changes the lineshape of the signal, from a simple peak to a peak-dip structure. Therefore, a robust prediction of this interference at NLO accuracy in QCD is necessary to ensure that higher-order corrections do not alter the lineshapes. We compute the exact NLO corrections, assuming a point-like coupling between the scalar and the gluons and consistently embedding the calculation in an effective field theory within an automated framework, and present results for a representative set of beyond the SM benchmarks. The results can be further matched to parton shower simulation, providing more realistic predictions. We find that NLO corrections are important and lead to a significant reduction of the uncertainties. We also discuss how our computation can be used to improve the predictions for physics scenarios where the gluon-scalar loop is resolved and the effective approach is less applicable.

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“…Measurements of the top quark polarisation may give hints of physics beyond the SM. The top quark is expected to be unpolarised in the SM due to parity conservation in QCD, however some beyond SM models predict top quark production involving positive or negative polarisation [5].…”

Section: Top Quark Polarisationmentioning

confidence: 99%

Measurement of the Top Quark Properties with the ATLAS Detector

Guindon

2013

EPJ Web of Conferences

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Abstract. The top quark, discovered at the Tevatron in 1995 by the CDF and DØ collaborations, is the heaviest known particle. The measurement of its properties are of interest to the understanding of the strong and weak forces, as well as searches for physics beyond the Standard Model. Several measurements of top quark properties are presented using data collected at the ATLAS experiment located at the Large Hadron Collider (LHC) at √ s = 7 TeV centre-of-mass energy. The measurements include top quark polarisation, spin correlation, production of ttZ and ttγ, as well as top mass and W tb vertex measurements in both the lepton + jets and dilepton channel.

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Top pair invariant mass distribution: a window on new physics

Cited by 170 publications

References 87 publications

LHC predictions from a tevatron anomaly in the top quark forward-backward asymmetry

LHC predictions from a tevatron anomaly in the top quark forward-backward asymmetry

Scalar production and decay to top quarks including interference effects at NLO in QCD in an EFT approach

Measurement of the Top Quark Properties with the ATLAS Detector

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