QCD Beyond Leading Power

Abstract

In this thesis I study the infrared limits of QCD beyond leading power by developing effective quantum field theory techniques. I introduce the motivations for studying this subject both as a tool to deepen our understanding of the infrared structure of gauge theory amplitudes and cross sections in the soft, collinear and Regge limit as well as to improve predictions for collider observables. Using and extending the framework of Soft and Collinear Effective Theory (SCET), I explore the ingredients of factorization beyond leading power constructing subleading hard scattering operators and radiative jet and soft functions for processes such as Higgs production and Drell-Yan. I introduce new subleading power gauge invariant objects, the $\theta$-jet and $\theta$-soft functions, which arise in the renormalization of subleading power operators. I use them to achieve the first resummation of collinear and soft logarithms beyond leading power for a collider observable in QCD. I study the perturbative power corrections to differential distributions for color singlet production at the LHC retaining the full dependence on the kinematics of the color singlet. I highlight and solve the subtleties related to the regularization of rapidity divergences beyond leading power for which I propose a new regulator, the pure rapidity regulator. I present a new method to employ cutting edge multiloop techniques for the computation of the expansions of cross sections in the collinear limit. This allows the extraction of universal ingredients arising in the collinear limit of QCD to an unprecedented level of precision in perturbation theory. Finally, I study the Regge limit at the amplitude and cross section level beyond leading power, developing a Lagrangian formalism for the treatment of fermion mediated forward scattering processes in QCD and applying it to obtain the quark reggeization and BFKL resummation.

Ph.D. thesis, MIT, 2020, 419 pages, very large number of figures

References in corpus (52)

• An NNLO subtraction formalism in hadron collisions and its application to Higgs boson production at the LHC
• Vector boson production at hadron colliders: a fully exclusive QCD calculation at NNLO
• Higgs boson gluon-fusion production in N3LO QCD
• Drell-Yan production at small q_T, transverse parton distributions and the collinear anomaly
• ZZ production at hadron colliders in NNLO QCD
• Thrust at N^3LL with Power Corrections and a Precision Global Fit for alphas(mZ)
• Evidence for a New Soft Graviton Theorem
• Jets from Massive Unstable Particles: Top-Mass Determination
• Bootstrapping a Five-Loop Amplitude Using Steinmann Relations
• 4D Scattering Amplitudes and Asymptotic Symmetries from 2D CFT
• Top Jets in the Peak Region: Factorization Analysis with NLL Resummation
• On Loop Corrections to Subleading Soft Behavior of Gluons and Gravitons
• QCD transverse-momentum resummation in gluon fusion processes
• Loop Corrections to Soft Theorems in Gauge Theories and Gravity
• Soft-/rapidity- anomalous dimensions correspondence
• Associated ZH production at hadron colliders: the fully differential NNLO QCD calculation
• Resummation of heavy jet mass and comparison to LEP data
• Mixed QCD-electroweak O(α_sα) corrections to Drell-Yan processes in the resonance region: pole approximation and non-factorizable corrections
• Vector-Boson Fusion Higgs Pair Production at N${}^3$LO
• Resummation and NLO Matching of Event Shapes with Effective Field Theory
• Fully Unintegrated Parton Correlation Functions and Factorization in Lowest Order Hard Scattering
• On next-to-eikonal corrections to threshold resummation for the Drell-Yan and DIS cross sections
• Soft Factor Subtraction and Transverse Momentum Dependent Parton Distributions on Lattice
• Diagrammatic insights into next-to-soft corrections
• Resummed Higgs cross section at N${}^3$LL
• Next-to-leading Order Calculation of the Single Transverse Spin Asymmetry in the Drell-Yan Process
• Resummation of Transverse Momentum Distributions in Distribution Space
• The Soft Function for Exclusive N-Jet Production at Hadron Colliders
• A Precise Determination of ${\alpha }_s$ from the C-parameter Distribution
• Electroweak Sudakov Corrections using Effective Field Theory
• Four-gluon scattering at three loops, infrared structure and Regge limit
• Fragmentation in Jets at NNLO
• Two-loop splitting amplitudes and the single-real contribution to inclusive Higgs production at N3LO
• High-Energy Limit of QCD beyond Sudakov Approximation
• Reparameterization Invariant Collinear Operators
• Precise predictions for the angular coefficients in Z-boson production at the LHC
• Higgs production in bottom quark fusion: Matching the 4- and 5-flavour schemes to third order in the strong coupling
• On the one-loop calculations with Reggeized quarks
• Generalized double-logarithmic large-x resummation in inclusive deep-inelastic scattering
• The Fully-Differential Quark Beam Function at NNLO
• Quark beam function at next-to-next-to-next-to-leading order in perturbative QCD in the generalized large-$N_c$ approximation
• Rapidity divergences and valid definitions of parton densities
• Subleading Corrections To Thrust Using Effective Field Theory
• Analytic Boosted Boson Discrimination at the Large Hadron Collider
• Collinear expansion for color singlet cross sections
• NNLO zero-jettiness beam and soft functions to higher orders in the dimensional-regularization parameter $\epsilon$
• Next-to-Leading Order Hard Scattering Using Fully Unintegrated Parton Distribution Functions
• Improved resummation prediction on Higgs boson production at hadron colliders
• The Fully-Differential Gluon Beam Function at NNLO
• Threshold resummation to any order in (1-x)
• Colour unwound - disentangling colours for azimuthal asymmetries in Drell-Yan scattering
• All-order results for infrared and collinear singularities in massless gauge theories