Seeing in Color: Jet Superstructure

Gallicchio, Jason; Schwartz, Matthew D.

doi:10.1103/physrevlett.105.022001

Cited by 154 publications

(155 citation statements)

References 24 publications

(23 reference statements)

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“…Such a calculation is given in [38]. Then, more interesting observables may be approached, including, for example, the jet p T spectrum at large p T , jet substructure, such as jet masses or angularities [34], hadronic event shapes [39], or even possibly observables related to the color flow in an event [40].…”

Section: Discussionmentioning

confidence: 99%

One-loop matching and next-to-next-to-leading log resummation for all partonic2→2processes in QCD

Kelley

Schwartz

2011

Phys. Rev. D

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The Wilson Coefficients for all 4-parton operators which arise in matching QCD to Soft-Collinear Effective Theory (SCET) are computed at 1-loop. Any dijet observable calculated in SCET beyond leading order will require these results. The Wilson coefficients are separated by spin and color, although most applications will involve only the spin-averaged hard functions. The anomalous dimensions for the Wilson coefficients are given to 2-loop order, and the renormalization group equations are solved explicitly. This will allow for analytical resummation of dijet observables to next-to-next-to-leading logarithmic accuracy. For each channel, there is a natural basis in which the evolution is diagonal in color space. The same basis also diagonalizes the color evolution for the soft function. Even though soft functions required for SCET calculations are observable dependent, it is shown that their renormalization group evolution is almost completely determined by a universal structure. With these results, it will be possible to calculate hadronic event shapes or other dijet observables to next-to-leading order with next-tonext-to-leading log resummation.

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Section: Discussionmentioning

confidence: 99%

One-loop matching and next-to-next-to-leading log resummation for all partonic2→2processes in QCD

Kelley

Schwartz

2011

Phys. Rev. D

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“…Here σ(p bi T ) = ap bi T + b reflects the jet p T dependence of the standard deviation of the pull angle for the two b-jets produced from Higgs decay, as noticed in [33]. For the kinematic regime that we are considering, a = −1 TeV −1 and b = 1.5 are assumed.…”

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confidence: 99%

“…Though an event may contribute more than one pair of b-jets for the resonance reconstruction, within the mass window all b-jet pairs are from different events. To rank the b-jet pairs in each event, the kinematics of jet pairs and jet superstructure [33] are employed. We use the p T of each b-jet pair, as well as the 'pull angle' of the pair.…”

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confidence: 99%

Multipleb-jets reveal top superpartners and the 125 GeV Higgs

2013

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We demonstrate that in supersymmetry (SUSY) with relatively light top superpartners, h → b b can be a very promising channel to discover the SM-like Higgs resonance at the Large Hadron Collider (LHC), although in general contexts it is thought to be challenging because of its huge QCD background. In this scenario, the SM-like Higgs boson is mainly produced via cascade decays initiated by pair-produced stop or sbottom squarks. The good sensitivity to h → b b owes a great deal to the application of multiple (≥ 4) b-jet tagging in removing the QCD background, and color-flow variables for reconstructing the Higgs resonance. We show in two benchmark points that a SM-like Higgs resonance can be discovered at the 14 TeV LHC (with a signal-to-background ratio as high as 0.35), with ∼ 40 fb −1 of data. Potentially, this strategy can be also applied to non-SUSY theories with cascade decays of top partners for the SM-like Higgs search, such as little Higgs, composite Higgs, and Randall-Sundrum models.

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“…It would be interesting to see how much more we can improve the significance of Higgs searches in hadronic channels by combining the analysis with other jet substructure [19][20][21] and color flow [22,23] observables, which probe softer sectors of QCD and color connections in an event. The approach of using multiple event interpretations could potentially be combined with likelihood ratio test and multivariate analysis, and in the presence of pile up our method will have to combine with jet grooming techniques.…”

Section: Figmentioning

confidence: 99%

Telescoping jets: Probing hadronic event structure with multipleR’s

Chien

2014

Phys. Rev. D

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Jets at high energy colliders are complicated objects to identify. Even if jets are widely separated, there is no reason for jets to have the same size. A single reconstruction, or interpretation, of each event can only extract a limited amount of information. Motivated by the recently proposed Qjet algorithms, which give multiple interpretations for each event using nondeterministic jet clustering, we propose a simple, fast and powerful method to give multiple event interpretations by varying the parameter R in the jet definition. With multiple interpretations we can redefine the weight of each event in a counting experiment to be the fraction of interpretations passing the experimental cuts, instead of 0 or 1 in a conventional analysis. We show that the statistical power of an analysis can be dramatically increased. In particular, we can have a 46% improvement in the statistical significance for the Higgs search with an associated Z boson (ZH → ννbb) at the 8 TeV LHC.Jets are manifestations of the underlying colored partons in hard scattering processes. In order to reconstruct hard processes and uncover physics at high energy, jets are key objects to identify in high energy collider experiments. The conventional way to identify jets is to use clustering algorithms [1][2][3][4][5], where a parameter R sets an artificial jet size. The constituents of each reconstructed jet are those particles within an angular scale R away from the jet direction. This is particularly true for the anti-k T algorithm because it gives almost perfect cone jets in the calorimeter pseudorapidity-azimuthal angle (η-φ) plane. On the other hand, a jet is a distinct structure in its own right with many collinear particles. The width of the localized energy distribution of the jet in the η-φ plane is an independent quantity and should be distinguished from the parameter R (FIG. 1).Because the formation of jets is quantum mechanical and probabilistic, the widths of jets are always different (FIG. 2). To reconstruct partonic kinematics we should pick a large enough R so that most of the radiation emitted by the partons is enclosed. However, with a large R more radiation contamination will be included. We can R is an artificial distance scale introduced to define the calorimeter region we want to look at. The jet axis points in the direction of the dominant energy flow, and the precise direction is not essential here.

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Seeing in Color: Jet Superstructure

Cited by 154 publications

References 24 publications

One-loop matching and next-to-next-to-leading log resummation for all partonic2→2processes in QCD

One-loop matching and next-to-next-to-leading log resummation for all partonic2→2processes in QCD

Multipleb-jets reveal top superpartners and the 125 GeV Higgs

Telescoping jets: Probing hadronic event structure with multipleR’s

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