Two-loop massive quark jet functions in SCET

Using Soft-Collinear Effective Theory, we develop the transverse-momentum-dependent factorization formalism for heavy flavor dijet production in polarized-proton-electron collisions. We consider heavy flavor mass corrections in the collinear-soft and jet functions, as well as the associated evolution equations. Using this formalism, we generate a prediction for the gluon Sivers asymmetry for charm and bottom dijet production at the future Electron-Ion Collider. Furthermore, we compare theoretical predictions with and without the inclusion of finite quark masses. We find that the heavy flavor mass effects can give sizable corrections to the predicted asymmetry.

Section: Massive Quark Jet Functionmentioning

confidence: 99%

QCD evolution of the gluon Sivers function in heavy flavor dijet production at the Electron-Ion Collider

Kang

Reiten

Shao

et al. 2021

“…This is achieved by matching SCET onto boosted heavy-quark effective theory (bHQET). For jettiness all the ingredients necessary to build an N 3 LL-accurate cross section are known: bHQET jet function [40], SCET massive jet function [41], and bHQET matching coefficient [42], as well as the secondary production contributions [43,44] (all up to two-loop level). The computations carried out in this article make possible N 2 LL resummation both in SCET and bHQET for other classes of event shapes.…”

Section: Jhep09(2020)132mentioning

confidence: 99%

“…[81,82]. The massive SCET jet function at O(α 2 s ) is definitely much more involved, and so far results only exist for 2-jettiness [41], which is certainly simpler since it can be computed as the imaginary part of a forward-scattering matrix element, such that the usual machinery for multi-loop computations can be applied.…”

Section: Jhep09(2020)132mentioning

confidence: 99%

Massive event-shape distributions at N2LL

Bris

Mateu

Preisser

2020

In a recent paper we have shown how to optimally compute the differential and cumulative cross sections for massive event-shapes at $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s in full QCD. In the present article we complete our study by obtaining resummed expressions for non-recoil-sensitive observables to N2LL + $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s precision. Our results can be used for thrust, heavy jet mass and C-parameter distributions in any massive scheme, and are easily generalized to angularities and other event shapes. We show that the so-called E- and P-schemes coincide in the collinear limit, and compute the missing pieces to achieve this level of accuracy: the P-scheme massive jet function in Soft-Collinear Effective Theory (SCET) and boosted Heavy Quark Effective Theory (bHQET). The resummed expression is subsequently matched into fixed-order QCD to extend its validity towards the tail and far- tail of the distribution. The computation of the jet function cannot be cast as the dis- continuity of a forward-scattering matrix element, and involves phase space integrals in d = 4 − 2ε dimensions. We show how to analytically solve the renormalization group equation for the P-scheme SCET jet function, which is significantly more complicated than its 2-jettiness counterpart, and derive rapidly-convergent expansions in various kinematic regimes. Finally, we perform a numerical study to pin down when mass effects become more relevant.

“…An example of a massive quark (initiated) jet function is given in refs. [37,38], and an example of an infrared-unsafe jet observable is the electric charge of the jet [39,40].…”

Section: Jhep10(2020)118mentioning

confidence: 99%

One-loop jet functions by geometric subtraction

Basdew-Sharma

Herzog

Velzen

et al. 2020

In factorization formulae for cross sections of scattering processes, final-state jets are described by jet functions, which are a crucial ingredient in the resummation of large logarithms. We present an approach to calculate generic one-loop jet functions, by using the geometric subtraction scheme. This method leads to local counterterms generated from a slicing procedure; and whose analytic integration is particularly simple. The poles are obtained analytically, up to an integration over the azimuthal angle for the observable- dependent soft counterterm. The poles depend only on the soft limit of the observable, characterized by a power law, and the finite term is written as a numerical integral. We illustrate our method by reproducing the known expressions for the jet function for angularities, the jet shape, and jets defined through a cone or kT algorithm. As a new result, we obtain the one-loop jet function for an angularity measurement in e+e− collisions, that accounts for the formally power-suppressed but potentially large effect of recoil. An implementation of our approach is made available as the GOJet Mathematica package accompanying this paper.