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City University of New York (CUNY)

Perturbative QCD

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Full-Text Articles in Physics

Resummation Of Non-Global Logarithms In Cross Sections With Massive Particles, Marcel Balsiger, Thomas Becher, Andrea Ferroglia Sep 2020

Resummation Of Non-Global Logarithms In Cross Sections With Massive Particles, Marcel Balsiger, Thomas Becher, Andrea Ferroglia

Publications and Research

A factorization formalism for jet processes involving massive colored particles such as the top quark is developed, extending earlier results for the massless case. The factorization of soft emissions from the underlying hard process is implemented in an effec tive field theory framework, which forms the basis for the resummation of large logarithms. The renormalization group evolution giving rise to non-global logarithms is implemented into a parton shower code in the large-Nc limit. After a comparison of the massive and massless radiation patterns, the cross section for t¯ t production with a veto on additional central jet activity is computed, …


Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich Jan 2020

Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich

Publications and Research

We consider double gg → g production in the presence of a bias on the unintegrated gluon distribution of the colliding hadrons or nuclei. Such bias could be due to the selection of configurations with a greater number of gluons or higher mean transverse momentum squared or, more generally, due to a modified spectral shape of the gluon distribution in the hadrons. Hence, we consider reweighted functional averages over the stochastic ensemble of small-x gluons. We evaluate explicitly the double inclusive gluon transverse momentum spectrum in high-energy collisions, and their azimuthal correlations, for a few simple examples of biases.


Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel Sep 2019

Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel

Publications and Research

We present the analytic calculation of the Master Integrals for the two loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equa tions, we expand the integrals in powers of the dimensional regulator and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.


Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel Aug 2019

Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel

Publications and Research

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator ε and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.


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 Aug 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 (αsαj+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 corrections resummed …


Measuring The Weizsäcker-Williams Distribution Of Linearly Polarized Gluons At An Electron-Ion Collider Through Dijet Azimuthal Asymmetries, Adrian Dumitru, Vladimir Skokov, Thomas Ullrich Jan 2019

Measuring The Weizsäcker-Williams Distribution Of Linearly Polarized Gluons At An Electron-Ion Collider Through Dijet Azimuthal Asymmetries, Adrian Dumitru, Vladimir Skokov, Thomas Ullrich

Publications and Research

The production of a hard dijet with small transverse momentum imbalance in semi-inclusive DIS probes the conventional and linearly polarized Weizsäcker-Williams (WW) transverse momentum dependent (TMD) gluon distributions. The latter, in particular, gives rise to an azimuthal dependence of the dijet cross section. In this paper we analyze the feasibility of a measurement of these TMDs through dijet production in DIS on a nucleus at an electron-ion collider. We introduce the MCDIJET Monte Carlo generator to sample quark-antiquark dijet configurations based on leading-order parton level cross sections with WW gluon distributions that solve the nonlinear small-x QCD evolution equations. …