Inclusive b and b anti-b production with quasi-multi-Regge kinematics at the Tevatron

TL;DR

The paper investigates inclusive b-jet and bbbar production at the Tevatron using quasi-multi-Regge kinematics with Reggeized partons. It derives LO and dominant NLO QMRK amplitudes and employs the KMR prescription for unintegrated PDFs, benchmarking against CDF Run II data without parameter tuning. The results show good agreement with measurements of single b-jets and bbbar dijets across multiple observables, with clear indications that Reggeized-quark–gluon and Reggeized-gluon fusion channels drive the dominant contributions. This work supports high-energy factorization and the QMRK framework as a competitive approach for perturbative QCD in the small-x, high-energy regime.

Abstract

We consider b-jet hadroproduction in the quasi-multi-Regge-kinematics approach based on the hypothesis of gluon and quark Reggeization in t-channel exchanges at high energies. The preliminary data on inclusive b-jet and b anti-b-dijet production taken by the CDF Collaboration at the Fermilab Tevatron are well described without adjusting parameters. We find the main contribution to inclusive b-jet production to be the scattering of a Reggeized gluon and a Reggeized b-quark to a b quark, which is described by the effective Reggeon-Reggeon-quark vertex. The main contribution to b anti-b-pair production arises from the scattering of two Reggeized gluons to a b anti-b pair, which is described by the effective Reggeon-Reggeon-quark-quark vertex. Our anaysis is based on the Kimber-Martin-Ryskin prescription for unintegrated gluon and quark distribution functions using as input the Martin-Roberts-Stirling-Thorne collinear parton distribution functions of the proton.

Figures (4)

• Figure 1: The transverse-momentum distribution of inclusive single $b$-jet hadroproduction measured by the CDF Collaboration at Tevatron Run II CDF1 is compared with the QMRK predictions due to subprocesses (\ref{['equ:RQ']}) 1 and (\ref{['equ:RRqq']}) 2. The shaded bands indicate the theoretical uncertainties.
• Figure 2: The leading-jet transverse-energy distribution of inclusive $b\bar{b}$-dijet hadroproduction measured by the CDF Collaboration at Tevatron Run II CDF2 is compared with the QMRK predictions due to subprocesses (\ref{['equ:RRqq']}) 1, (\ref{['eq:QQbb']}) 2, and their sum 3. The shaded band indicates the theoretical uncertainty on the latter.
• Figure 3: The dijet-invariant-mass distribution of inclusive $b\bar{b}$-dijet hadroproduction measured by the CDF Collaboration at Tevatron Run II CDF2 is compared with the QMRK predictions due to subprocesses (\ref{['equ:RRqq']}) 1, (\ref{['eq:QQbb']}) 2, and their sum 3. The shaded band indicates the theoretical uncertainty on the latter.
• Figure 4: The azimuthal-separation-angle distribution of inclusive $b\bar{b}$-dijet hadroproduction measured by the CDF Collaboration at Tevatron Run II CDF2 is compared with the QMRK predictions due to subprocesses (\ref{['equ:RRqq']}) 1, (\ref{['eq:QQbb']}) 2, and their sum 3. The shaded band indicates the theoretical uncertainty on the latter.