科研之友
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摘要
The production of high-mass, color-singlet particles in hadron collisions is universally accompanied by initial state QCD radiation that is predominantly soft with respect to the hard process scale Q and/or collinear with respect to the beam axis. At TeV-scale colliders, this is in contrast to top quark and multijet processes, which are hard and central. Consequently, vetoing events with jets possessing transverse momenta above p(T)(Veto) in searches for new color-singlet states can efficiently reduce non-singlet backgrounds, thereby increasing experimental sensitivity. To quantify this generic observation, we investigate the production and leptonic decay of a Sequential Standard Model W ' boson at the 13TeV Large Hadron Collider. We systematically consider signal and background processes at next-to-leading- order (NLO) in QCD with parton shower (PS) matching. For color- singlet signal and background channels, we resum Sudakov logarithms of the form alpha(j)(s)(p(T)(Veto) T) log(k) (Q/p(T)(Veto)) up to next-to-next-to-leading logarithmic accuracy (NNLL) with NLO matching. We obtain our results using the MADGRAPH5_AMC@NLO and MADGRAPH5_AMC@NLO-SCET frameworks, respectively. Associated Universal FEYN-RULES Output model files capable of handling NLO+PS- and NLO+NNLL-accurate computations are publicly available. We find that within their given uncertainties, both the NLO+PS and NLO+NNLL(veto) calculations give accurate and consistent predictions. Consequently, jet vetoes applied to color- singlet processes can be reliably modeled at the NLO+PS level. With respect to a b-jet veto of p(T)(Veto) = 30 GeV, flavor-agnostic jet vetoes of p(T)(Veto) = 30 - 40 GeV can further reduce single top and t (t) over bar rates by a factor of 2-50 at a mild cost of the signal rate. Jet vetoes can increase the signal-to-noise ratios by roughly 10% for light W ' boson masses of 30 - 50 GeV and 25%-250% for masses of 300-800 GeV.
- 出版日期2017-5-8
