Summary of the Topical Workshop on Top Quark Differential Distributions 2014

TL;DR

The paper documents the 2014 Top Quark Differential Distributions workshop, focusing on the impact of NNLO and NLO+PS precision calculations for top-quark production on LHC measurements, PDF determinations, and BSM searches. It reviews differential NNLO results, merging techniques for realistic final states, fiducial-region measurement strategies, and the potential to constrain gluon PDFs and improve top-related BSM sensitivity. It also discusses approximate higher-order methods and the importance of MC tunes and cross-section ratio measurements to fully exploit current and future data. The overarching message is that integrating precise theory with fiducial measurements and cross-channel ratios will sharpen SM tests and enhance sensitivity to new physics involving top quarks at the LHC.

Abstract

We summarise the Topical Workshop on Top Quark Differential Distributions 2014, which took place in Cannes immediately before the annual Top2014 conference. The workshop was motivated by the availability of top quark differential distributions at NNLO and the forthcoming LHC 13 TeV data. The main goal of the workshop was to explore the impact of improved calculations of top quark production on precision LHC measurements, PDF determinations and searches for physics beyond the Standard Model, as well as finding ways in which the high precision data from ATLAS, CMS and LHCb can be used to further refine theoretical predictions for top production.

Figures (5)

• Figure 1: Schematic illustration of recent theoretical progress in theory calculations of top quark production in complementary directions: NNLO calculations, merging of NLO+PS samples of different multiplicities and results beyond stable tops (courtesy of M. Schultze).
• Figure 2: Left plot: preliminary results for the invariant mass distribution $M_{tt}$ for top quark pair production at the Tevatron at NNLO accuracy. Right plot: NNLO cross-section for the production of single top quarks at the LHC 7 TeV, as a function of the cut in the $p_T$ of the top quark Brucherseifer:2014ama.
• Figure 3: Left plot: $H_T$ distribution in $t\bar{t}$+jets events at the LHC 7 TeV in the MEPS@NLO approach, compared to samples with exclusive jet multiplicities. Right plot: the $m_{lb}$ distribution computed at NLO at the LHC 7 TeV, for different values of the top quark mass.
• Figure 4: Left plot: the 7 TeV ATLAS measurements of the $p_T$ of top quarks, compared to various PDF sets. Right plot: the reduction of the gluon large-$x$ PDF uncertainties when inclusive top quark cross-sections are added to the NNPDF2.3 NNLO fit Ball:2012cx.
• Figure 5: Left plot: schematic illustration of the different extreme kinematical regions probed by BSM searches at the LHC with top quarks in the final state (courtesy of F. Blekman). Right plot: the reconstructed mass of a top quark pair $m_{tt}^{\rm reco}$ in BSM scenarios where a heavy resonance $\rho$ decays into a $t\bar{t}$ pair (red histogram) or to other intermediate resonances which in turn decay to top quarks (blue and green histograms), from Chala:2014mmam.