Back-to-back azimuthal correlations in $$\mathrm {Z} +$$jet events at high transverse momentum in the TMD parton branching method at next-to-leading order

Abstract

Azimuthal correlations in $$\mathrm {Z} +$$ Z + jet production at large transverse momenta are computed by matching Parton-Branching (PB) TMD parton distributions and showers with NLO calculations via MCatNLO. The predictions are compared with those for dijet production in the same kinematic range. The azimuthal correlations $$\Delta \phi $$ Δ ϕ between the Z boson and the leading jet are steeper compared to those in dijet production at transverse momenta $$\mathcal{O}(100)$$ O ( 100 ) GeV , while they become similar for very high transverse momenta $${{\mathcal {O}}}(1000)$$ O ( 1000 ) GeV . The different patterns of $$\mathrm {Z} +$$ Z + jet and dijet azimuthal correlations can be used to search for potential factorization-breaking effects in the back-to-back region, which depend on the different color and spin structure of the final states and their interferences with the initial states. In order to investigate these effects experimentally, we propose to measure the ratio of the distributions in $$\Delta \phi $$ Δ ϕ for $$\mathrm {Z} +$$ Z + jet- and multijet production at low and at high transverse momenta, and compare the results to predictions obtained assuming factorization. We examine the role of theoretical uncertainties by performing variations of the factorization scale, renormalization scale and matching scale. In particular, we present a comparative study of matching scale uncertainties in the cases of PB-TMD and collinear parton showers.

NLO Analysis of Small $k_T$ Region in Drell-Yan Production with Parton Branching

“…To investigate various low-T spectrum contributions across different DY and √ scenarios, we employ the PB TMD method, as outlined in [4,5]. This involves extracting NLO hardscattering matrix elements from M G 5_ MC@NLO and matching them with TMD parton distributions and showers derived from PB evolution, using the subtractive matching procedure introduced in [6]. The PB evolution equations for TMD parton distributions A ( , k, 2 ) of flavor are given by:…”

“…We incorporate TMD parton distributions and parton showers into the MCatNLO calculation using C 3 [9], as discussed in detail in Ref. [6]. We utilize the Herwig 6 subtraction terms in MCatNLO, which are consistent with the PB-set TMD parton distribution sets described earlier.…”

Azimuthal decorrelation for photon induced dijet production in ultra-peripheral collisions of heavy ions

“…Starting with the pioneering papers [50,51], all-order resummation of azimuthal decorrelation for QCD jets has been performed in various processes [52][53][54][55][56][57][58][59][60][61][62][63][64]. Usually, fixed-order calculations in pQCD can be used to systematically improve the description of hadronic radiation.…”

“…Before introducing our methodology, we first briefly describe two methods on the market used to perform resummation of large logarithms of the azimuthal angle for jets [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64]. The first method is deriving an all-order resummation formula for the transverse momentum imbalance q T , and then constructing the azimuthal decorrelation ∆φ distribution from the q T distribution, which can be named as the "indirect method".…”

Azimuthal decorrelation between a jet and a Z boson at hadron colliders

“…The observable of interest in this paper, i.e., the azimuthal decorrelation between a Z boson and a jet produced in hadron-hadron collisions, has been studied in refs. [14][15][16][17][18][19].…”