Transverse energy–energy correlations of jets in the electron–proton deep inelastic scattering at HERA

Ali, Ahmed; Xing, Zhi-Peng; Li, Gang; Wang, Wei

doi:10.1140/epjc/s10052-020-08614-3

Journal Article

PUBDB-2021-01450

Transverse energy–energy correlations of jets in the electron–proton deep inelastic scattering at HERA

Ali, A.DESY* ; Li, G.DESY* ; Wang, W. (Corresponding author)Extern* ; Xing, Z.-P.

2020
Springer Heidelberg

The European physical journal / C 80(12), 1096 (2020) [10.1140/epjc/s10052-020-08614-3]

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Please use a persistent id in citations: doi:10.1140/epjc/s10052-020-08614-3 doi:10.3204/PUBDB-2021-01450

Report No.: ACFI-T20-09; DESY-20-129; arXiv:2008.00271

Abstract: We study the event shape variables, transverse energy–energy correlation TEEC $(\cos \phi )$ and its asymmetry ATEEC $(\cos \phi )$ in deep inelastic scattering (DIS) at the electron–proton collider HERA, where $\phi $ is the angle between two jets defined using a transverse-momentum $(k_T)$ jet algorithm. At HERA, jets are defined in the Breit frame, and the leading nontrivial transverse energy–energy correlations arise from the 3-jet configurations. With the help of the NLOJET++, these functions are calculated in the leading order (LO) and the next-to-leading order (NLO) approximations in QCD at the electron–proton center-of-mass energy $\sqrt{s}=314$ GeV. We restrict the angular region to $-0.8 \le \cos \phi \le 0.8$, as the forward- and backward-angular regions require resummed logarithmic corrections, which we have neglected in this work. Following experimental jet-analysis at HERA, we restrict the DIS-variables x, $y=Q^2/(x s)$, where $Q^2=-q^2$ is the negative of the momentum transfer squared $q^2$, to $0 \le x \le 1$, $0.2 \le y \le 0.6$, and the pseudo-rapidity variable in the laboratory frame $(\eta ^\mathrm{{lab}})$ to the range $-1 \le \eta ^\mathrm{{lab}} \le 2.5$. The TEEC and ATEEC functions are worked out for two ranges in $Q^2$, defined by $5.5\,\mathrm{GeV}^2 \le Q^2 \le 80\,\mathrm{GeV}^2$, called the low-$Q^2$-range, and $150\,\mathrm{GeV}^2 \le Q^2 \le 1000\,\mathrm{GeV}^2$, called the high-$Q^2$-range. We show the sensitivity of these functions on the parton distribution functions (PDFs), the factorization $(\mu _F)$ and renormalization $(\mu _R)$ scales, and on $\alpha _s(M_Z^2)$. Of these the correlations are stable against varying the scale $\mu _F$ and the PDFs, but they do depend on $\mu _R$. For the choice of the scale $\mu _R= \sqrt{\langle E_T\rangle ^2 +Q^2}$, advocated in earlier jet analysis at HERA, the shape variables TEEC and ATEEC are found perturbatively robust. These studies are useful in the analysis of the HERA data, including the determination of $\alpha _s(M_Z^2)$ from the shape variables.

Keyword(s): parton: distribution function ; jet: production ; transverse energy ; correlation ; electron p: deep inelastic scattering ; higher-order: 0 ; higher-order: 1 ; DESY HERA Stor ; quantum chromodynamics ; event shape analysis ; scale: renormalization ; factorization ; Breit frame ; stability ; asymmetry

Classification:

ddc:530

Note: 18 pages,11 figures; v2: 16 pages, accepted for publication in EPJC

Contributing Institute(s):

Research Program(s):

611 - Fundamental Particles and Forces (POF3-611) (POF3-611)

Experiment(s):

HERA: HERA-B

Appears in the scientific report 2020

Database coverage:
Medline

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