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

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 bemore » used to improve the predictions for physics scenarios where the gluon-scalar loop is resolved and the effective approach is less applicable.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Gottingen Univ. (Germany). Inst. of Physics
  2. Nikhef, Amsterdam (Netherlands)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Physics; Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics
Publication Date:
Report Number(s):
BNL-114557-2017-JA
Journal ID: ISSN 1029-8479; KA2401012; TRN: US1800335
Grant/Contract Number:
SC0012704; 722104
Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2017; Journal Issue: 10; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States); Nikhef, Amsterdam (Netherlands); Chinese Academy of Sciences (CAS), Beijing (China)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); European Union (EU); Netherlands Organisation for Scientific Research (NWO); Chinese Academy of Sciences (CAS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; NLO computations; QCD phenomenology
OSTI Identifier:
1412736