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Factorization and resummation for groomed multi-prong jet shapes

Observables which distinguish boosted topologies from QCD jets are playing an increasingly important role at the Large Hadron Collider (LHC). These observables are often used in conjunction with jet grooming algorithms, which reduce contamination from both theoretical and experimental sources. In this paper we derive factorization formulae for groomed multi-prong substructure...

Casimir meets Poisson: improved quark/gluon discrimination with counting observables

Charged track multiplicity is among the most powerful observables for discriminating quark- from gluon-initiated jets. Despite its utility, it is not infrared and collinear (IRC) safe, so perturbative calculations are limited to studying the energy evolution of multiplicity moments. While IRC-safe observables, like jet mass, are perturbatively calculable, their distributions...

Soft-collinear supersymmetry

Soft-Collinear Effective Theory (SCET) is a framework for modeling the infrared structure of theories whose long distance behavior is dominated by soft and collinear divergences. This paper demonstrates that SCET can be made compatible with super-symmetry (SUSY). Explicitly, the effective Lagrangian for \( \mathcal{N}=1 \) SUSY Yang-Mills is cconstructed and shown to be a...

The analytic structure of non-global logarithms: convergence of the dressed gluon expansion

Non-global logarithms (NGLs) are the leading manifestation of correlations between distinct phase space regions in QCD and gauge theories and have proven a challenge to understand using traditional resummation techniques. Recently, the dressed gluon ex-pansion was introduced that enables an expansion of the NGL series in terms of a “dressed gluon” building block, defined by an...

Analytic boosted boson discrimination

Observables which discriminate boosted topologies from massive QCD jets are of great importance for the success of the jet substructure program at the Large Hadron Collider. Such observables, while both widely and successfully used, have been studied almost exclusively with Monte Carlo simulations. In this paper we present the first all-orders factorization theorem for a two...

Factorization for groomed jet substructure beyond the next-to-leading logarithm

Jet grooming algorithms are widely used in experimental analyses at hadron colliders to remove contaminating radiation from within jets. While the algorithms perform a great service to the experiments, their intricate algorithmic structure and multiple parameters has frustrated precision theoretic understanding. In this paper, we demonstrate that one particular groomer called...

Non-global logarithms, factorization, and the soft substructure of jets

An outstanding problem in QCD and jet physics is the factorization and resummation of logarithms that arise due to phase space constraints, so-called non-global logarithms (NGLs). In this paper, we show that NGLs can be factorized and resummed down to an unresolved infrared scale by making sufficiently many measurements on a jet or other restricted phase space region. Resummation...

Tracking down hyper-boosted top quarks

The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be...

Power counting to better jet observables

Optimized jet substructure observables for identifying boosted topologies will play an essential role in maximizing the physics reach of the Large Hadron Collider. Ideally, the design of discriminating variables would be informed by analytic calculations in perturbative QCD. Unfortunately, explicit calculations are often not feasible due to the complexity of the observables used...

Toward multi-differential cross sections: measuring two angularities on a single jet

Andrew J. Larkoski 0 Ian Moult 0 Duff Neill 0 0 Center for Theoretical Physics, Massachusetts Institute of Technology , Cambridge, MA 02139, U.S.A The analytic study of differential cross

Soft theorems from effective field theory

The singular limits of massless gauge theory amplitudes are described by an effective theory, called soft-collinear effective theory (SCET), which has been applied most successfully to make all-orders predictions for observables in collider physics and weak decays. At tree-level, the emission of a soft gauge boson at subleading order in its energy is given by the Low-Burnett...

Jet shapes with the broadening axis

Andrew J. Larkoski 0 Duff Neill 0 Jesse Thaler 0 0 Center for Theoretical Physics, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, U.S.A Broadening is a

Gaining (mutual) information about quark/gluon discrimination

Discriminating quark jets from gluon jets is an important but challenging problem in jet substructure. In this paper, we use the concept of mutual information to illuminate the physics of quark/gluon tagging. Ideal quark/gluon separation requires only one bit of truth information, so even if two discriminant variables are largely uncorrelated, they can still share the same “truth...

Soft drop

We introduce a new jet substructure technique called “soft drop declustering”, which recursively removes soft wide-angle radiation from a jet. The soft drop algorithm depends on two parameters — a soft threshold z cut and an angular exponent β — with the β = 0 limit corresponding roughly to the (modified) mass drop procedure. To gain an analytic understanding of soft drop and...

Angular scaling in jets

Martin Jankowiak 0 Andrew J. Larkoski 0 0 SLAC, Menlo Park, CA 94025 , U.S.A. SITP, Stanford University , STANFORD, CA 94305, U.S.A We introduce a jet shape observable dened for an ensemble of jets

Jet substructure without trees

Martin Jankowiak 0 Andrew J. Larkoski larkoski@stanford.edu 0 0 SLAC, Menlo Park, CA 94025 , U.S.A. SITP, Stanford University , Stanford, CA 94305, U.S.A We present an alternative approach to

Energy correlation functions for jet substructure

We show how generalized energy correlation functions can be used as a powerful probe of jet substructure. These correlation functions are based on the energies and pair-wise angles of particles within a jet, with (N + 1)-point correlators sensitive to N-prong substructure. Unlike many previous jet substructure methods, these correlation functions do not require the explicit...

Constructing amplitudes from their soft limits

Camille Boucher-Veronneau Andrew J. Larkoski SLAC Menlo Park CA U.S.A. The existence of universal soft limits for gauge-theory and gravity amplitudes has been known for a long time. The properties