Extending Precision Perturbative QCD with Track Functions

Li, Yibei; Moult, Ian; van Velzen, Solange Schrijnder; Waalewijn, Wouter J.; Zhu, Hua Xing

doi:10.48550/arxiv.2108.01674

Cited by 8 publications

(21 citation statements)

References 93 publications

(136 reference statements)

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“…The agreement between these two approaches provides a strong check both on our calculations and on the universality of the track functions. The universality of the first three moments of the track functions was tested at NLO in this same manner in [5]. Here we extend this to the sixth moment.…”

Section: Calculational Techniquementioning

confidence: 87%

Renormalization Group Flows for Track Function Moments

Jaarsma,

Li,

Moult

et al. 2022

Preprint

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Track functions describe the collective effect of the fragmentation of quarks and gluons into charged hadrons, making them a key ingredient for jet substructure measurements at hadron colliders, where track-based measurements offer superior angular resolution. The first moment of the track function, describing the average energy deposited in charged particles, is a simple and well-studied object. However, measurements of higher-point correlations of energy flow necessitate a characterization of fluctuations in the hadronization process, described theoretically by higher moments of the track function. In this paper we derive the structure of the renormalization group (RG) evolution equations for track function moments. We show that energy conservation gives rise to a shift symmetry that allows the evolution equations to be written in terms of cumulants, κ(N ), and the difference between the first moment of quark and gluon track functions, ∆. The uniqueness of the first three cumulants then fixes their all-order evolution to be DGLAP, up to corrections involving powers of ∆, that are numerically suppressed by an effective order in the perturbative expansion for phenomenological track functions. However, at the fourth cumulant and beyond there is non-trivial RG mixing into products of cumulants such as κ(4) into κ(2) 2 . We analytically compute the evolution equations up to the sixth moment at O(α 2 s ), and study the associated RG flows. These results allow for the study of up to six-point correlations in energy flow using tracks, paving the way for precision jet substructure at the LHC.

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Section: Calculational Techniquementioning

confidence: 87%

Renormalization Group Flows for Track Function Moments

Jaarsma,

Li,

Moult

et al. 2022

Preprint

Self Cite

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“…This pro correlation functions of ANEC oper recent developments in the study o concrete situation for studying the b There has recently been signific number of di↵erent directions. For g leading order (NLO) in QCD [8,9] and up to NNLO in N = 4 SYM [7, NNLO [11,12].…”

Section: Energy Correlators From a Perturbative Qcd Perspectivementioning

confidence: 99%

“…We have highlighted the terms of highest transverse spin in blue in (2.15). 12 The leading terms in the power expansion of |w| have been studied in detail in [27]. They are interesting as they are the manifestation of gluon spin in jet substructure [27], and also allow one to test parton shower implementations of spin correlations [49,[103][104][105][106][107].…”

Section: Energy Correlators From a Perturbative Qcd Perspectivementioning

confidence: 99%

“…Recently there has been a program [20] to reformulate questions of physical interest in jet substructure purely in terms of these correlation functions, as opposed to more traditional jet shapes. 3 This has lead to many exciting developments, including factorization theorems describing the behavior in the collinear limits [20,24], the calculation of multi-point correlators [25], calculations incorporating tracking information [12,20,26], the study of spin interference effects [27,28], applications to top quark mass measurements [29], and the first analysis of these correlators on real LHC data [30]! 4 This wealth of phenomenological applications motivates further developing the theoretical understanding of these correlation functions.…”

Section: Introductionmentioning

confidence: 99%

“…For early applications see[4][5][6], for reviews see[7][8][9] 2 More generally, charges other than energy flow can be studied (see e.g [10][11][12][13]…”

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confidence: 99%

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Celestial Blocks and Transverse Spin in the Three-Point Energy Correlator

Chen¹,

Moult²,

Sandor³

et al. 2022

Preprint

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Quantitative theoretical techniques for understanding the substructure of jets at the LHC enable new insights into the dynamics of QCD, and novel approaches to search for new physics. Recently, there has been a program to reformulate jet substructure in terms of correlation functions, E( n 1 )E( n 2 ) • • • E( n k ) , of light-ray operators, E( n), allowing the application of techniques developed in the study of Conformal Field Theories (CFTs). In this paper we further develop these techniques in the particular context of the three-point correlator E( n 1 )E( n 2 )E( n 3 ) , using recently computed perturbative data in both QCD and N = 4 sYM. We derive the celestial blocks appearing in the light-ray operator product expansion (OPE) of the three-point correlator, and use the Lorentzian inversion formula to extract the spectrum of light-ray operators appearing in the expansion, showing, in particular, that the OPE data is analytic in transverse spin. Throughout our presentation, we highlight the relation between the OPE approach, and more standard splitting function based approaches of perturbative QCD, emphasizing the utility of the OPE approach for incorporating symmetries in jet substructure calculations. We hope that our presentation introduces a number of new techniques to the jet substructure community, and also illustrates the phenomenological relevance of the study of light-ray operators in the OPE limit to the CFT community.

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Probing hadronization with flavor correlations of leading particles in jets

Chien,

Deshpande,

Mondal

et al. 2021

Preprint

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We study nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable rc that distinguishes same-and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, rc is examined as a function of various kinematic variables for different combinations of hadron species, and the feasibility of such measurements at the EIC is demonstrated. The precision hadronization study we propose will provide new tests of hadronization models and hopefully lead to improved quantitative, and perhaps eventually analytic, understanding of nonperturbative QCD dynamics.

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Extending Precision Perturbative QCD with Track Functions

Cited by 8 publications

References 93 publications

Renormalization Group Flows for Track Function Moments

Renormalization Group Flows for Track Function Moments

Celestial Blocks and Transverse Spin in the Three-Point Energy Correlator

Probing hadronization with flavor correlations of leading particles in jets

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