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City University of New York (CUNY)

QCD Phenomenology

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Full-Text Articles in Physics

Top-Quark Pair Hadroproduction In Association With A Heavy Boson At Nlo+Nnll Including Ew Corrections, Alessandro Broggio, Andrea Ferroglia, Rikkert Frederix, Davide Pagani, Benjamin D. Pecjak, Ioannis Tsinikos Jan 2019

Top-Quark Pair Hadroproduction In Association With A Heavy Boson At Nlo+Nnll Including Ew Corrections, Alessandro Broggio, Andrea Ferroglia, Rikkert Frederix, Davide Pagani, Benjamin D. Pecjak, Ioannis Tsinikos

Publications and Research

This work studies the associated production of a top-quark pair with a W, Z, or Higgs boson at the LHC. Predictions for the total cross sections as well as for several differential distributions of the massive particles in the final state are provided. These predictions, valid for the LHC operating at 13 TeV, include without any approximation all the NLO electroweak and QCD contributions of O(αisαj+1) with i + j = 2, 3. In addition, the predictions presented here improve upon the NLO QCD results by adding the effects of soft gluon emission …


Resummation For (Boosted) Top-Quark Pair Production At Nnlo+Nnll' In Qcd, Michał Czakon, Andrea Ferroglia, David Heymes, Alexander Mitov, Ben D. Pecjak, Darren J. Scott, Xing Wang, Li Lin Yang May 2018

Resummation For (Boosted) Top-Quark Pair Production At Nnlo+Nnll' In Qcd, Michał Czakon, Andrea Ferroglia, David Heymes, Alexander Mitov, Ben D. Pecjak, Darren J. Scott, Xing Wang, Li Lin Yang

Publications and Research

We construct predictions for top quark pair differential distributions at hadron colliders that combine state-of-the-art NNLO QCD calculations with double resummation at NNLL′ accuracy of threshold logarithms arising from soft gluon emissions and of small mass logarithms. This is the first time a resummed calculation at full NNLO+NNLL′ accuracy in QCD for a process with non-trivial color structure has been completed at the differential level. Of main interest to us is the stability of the $M_{t\bar{t}}$ and top-quark $p_T$ distributions in the boosted regime where fixed order calculations may become strongly dependent on the choice of dynamic scales. With the …


Nnll Resummation For The Associated Production Of A Top Pair And A Higgs Boson At The Lhc, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Li Lin Yang Feb 2017

Nnll Resummation For The Associated Production Of A Top Pair And A Higgs Boson At The Lhc, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Li Lin Yang

Publications and Research

We study the resummation of soft gluon emission corrections to the production of a top-antitop pair in association with a Higgs boson at the Large Hadron Collider. Starting from a soft-gluon resummation formula derived in previous work, we develop a bespoke parton-level Monte Carlo program which can be used to calculate the total cross section along with differential distributions. We use this tool to study the phenomenological impact of the resummation to next-to-next-to-leading logarithmic (NNLL) accuracy, finding that these corrections increase the total cross section and the differential distributions with respect to NLO calculations of the same observables.


Associated Production Of A Top Pair And A W Boson At Next-To-Next-To-Leading Logarithmic Accuracy, Alessandro Broggio, Andrea Ferroglia, Giovanni Ossola, Ben D. Pecjak Sep 2016

Associated Production Of A Top Pair And A W Boson At Next-To-Next-To-Leading Logarithmic Accuracy, Alessandro Broggio, Andrea Ferroglia, Giovanni Ossola, Ben D. Pecjak

Publications and Research

We consider soft gluon emission corrections to the production of a top-antitop pair in association with a W boson at the Large Hadron Collider. We obtain a soft-gluon resummation formula for this production process which is valid up to next-to-next-to-leading logarithmic accuracy. We evaluate the soft gluon resummation formula in Mellin space by means of an in-house parton level Monte Carlo code which allows us to obtain predictions for the total cross section as well as for several differential distributions. We study the impact of the soft-gluon resummation corrections in comparison to fixed order calculations.


Associated Production Of A Top Pair And A Higgs Boson Beyond Nlo, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Adrian Signer, Li Lin Yang Mar 2016

Associated Production Of A Top Pair And A Higgs Boson Beyond Nlo, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Adrian Signer, Li Lin Yang

Publications and Research

We consider soft gluon emission corrections to the production of a top-antitop pair in association with a Higgs boson at hadron colliders. In particular, we present a softgluon resummation formula for this production process and gather all elements needed to evaluate it at next-to-next-to-leading logarithmic order. We employ these results to obtain approximate next-to-next-to-leading order (NNLO) formulas, and implement them in a bespoke parton-level Monte Carlo program which can be used to calculate the total cross section along with arbitrary differential distributions. We use this tool to study the phenomenological impact of the approximate NNLO corrections, finding that they increase …


Nnlo Hard Functions In Massless Qcd, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Zhibai Zhang Dec 2014

Nnlo Hard Functions In Massless Qcd, Alessandro Broggio, Andrea Ferroglia, Ben D. Pecjak, Zhibai Zhang

Publications and Research

We derive the hard functions for all 2 → 2 processes in massless QCD up to next-to-next-to-leading order (NNLO) in the strong coupling constant. By employing the known one- and two-loop helicity amplitudes for these processes, we obtain analytic expressions for the ultraviolet and infrared finite, minimally subtracted hard functions, which are matrices in color space. These hard functions will be useful in carrying out higher-order resummations in processes such as dijet and highly energetic top-quark pair production by means of soft-collinear effective theory methods.


Nnll Momentum-Space Resummation For Stop-Pair Production At The Lhc, Alessandro Broggio, Andrea Ferroglia, Matthias Neubert, Leonardo Vernazza, Li Lin Yang Mar 2014

Nnll Momentum-Space Resummation For Stop-Pair Production At The Lhc, Alessandro Broggio, Andrea Ferroglia, Matthias Neubert, Leonardo Vernazza, Li Lin Yang

Publications and Research

If supersymmetry near the TeV scale is realized in Nature, the pair production of scalar top squarks is expected to be observable at the Large Hadron Collider. Recently, effective field-theory methods were employed to obtain approximate predictions for the cross section for this process, which include soft-gluon emission effects up to nextto- next-to-leading order (NNLO) in perturbation theory. In this work we employ the same techniques to resum soft-gluon emission effects to all orders in perturbation theory and with next-to-next-to-logarithmic (NNLL) accuracy. We analyze the effects of NNLL resummation on the stop-pair production cross section by obtaining NLO+NNLL predictions in …