We determine dominant next-to-next-to-leading order QCD corrections to single-inclusive jet production at the LHC and Tevatron, using the established threshold resummation framework. In contrast to previous literature on this topic, our study incorporates all of the following features: (1) It properly accounts for the way a jet is defined in experiment and treated in available full next-to-leading order calculations, (2) It includes the three leading classes of logarithmic terms in the perturbative expansion, and (3) It is adapted to the full kinematics in jet transverse momentum and rapidity relevant for experiments. A recent full next-to-next-to-leading order calculation in the purely gluonic channel allows us to assess the region where our approximate corrections provide an accurate description. We expect our results to be important on the way to precision jet phenomenology at the LHC and as benchmark for further full next-to-next-to-leading order calculations.PACS numbers: 12.38.Bx, 13.85.-t, 13.87.-aIntroduction. -The production of high-transversemomentum hadron jets plays a fundamental role at the LHC [1] and at Tevatron [2]. Jets are produced very copiously, making them precision probes of the physics of the Standard Model and beyond. Theoretical calculations whose precision matches that achievable in experiment are of critical importance. The efforts made in this context have spanned more than three decades now, culminating so far with the recent calculation of the next-tonext-to-leading order (NNLO) perturbative corrections to jet production in the "gluon-only" channel [3,4].As complete NNLO calculations of jet production are probably still a few years away, it is useful to determine approximate NNLO results, at least in certain kinematical regimes. This is possible thanks to the fact that the perturbative series for the partonic cross sections contains classes of logarithmic terms that often dominate. Resummation techniques in QCD [5] allow to determine the all-order structure of these logarithmic terms, and one therefore also obtains the logarithms present at NNLO. Knowledge of approximate NNLO expressions is very useful, since it potentially offers an avenue toward more precise phenomenology than available on the basis of the presently known full next-to-leading order (NLO) corrections. It also serves as benchmark for future full NNLO calculations.The logarithms just mentioned arise near a threshold from which the production of a jet becomes possible in a partonic collision. They are hence known as "threshold logarithms". The threshold is set by a vanishing invariant mass √ s 4 of the partonic system that recoils against

We investigate QCD threshold resummation effects beyond the next-to-leading logarithmic (NLL) order for the process H 1 H 2 → h 1 h 2 X at high invariant mass of the produced hadron pair. We take into account the color structure of the underlying partonic hard-scattering cross sections and determine the relevant hard and soft matrices in color space that contribute to the resummed cross section at next-to-next-to-leading logarithmic (NNLL) accuracy. We present numerical results for fixed-target and collider regimes. We find a significant improvement compared to previous results at NLL accuracy. In particular, the scale dependence of the resummed cross section is greatly reduced. Use of the most recent set of fragmentation functions also helps in improving the comparison with the experimental data. Our calculation provides a step towards a systematic NNLL extension of threshold resummation also for other hadronic processes, in particular for jet production.

Rev. D 92, 014001 (2015)] Corrected versions of Figs. 7(a) (upper panel, left) and 7(b) (upper panel, right), and Figs. 9(a) (lower panel, left) and 9(b) (lower panel, right).

We present next-to-leading order (NLO) perturbative-QCD calculations of the cross sections for N → hX and N → jet X. The main feature of these processes is that the scattered lepton is not observed, so that the hard scale that makes them perturbative is set by the transverse momentum of the hadron or jet. Kinematically, the two processes thus become direct analogs of single-inclusive production in hadronic collisions which, as has been pointed out in the literature, makes them promising tools for exploring transverse spin phenomena in QCD when the incident nucleon is transversely polarized. We find that the NLO corrections are sizable for the spinaveraged cross section. We also investigate in how far the scattering is dominated by the exchange of almost real (Weizsäcker-Williams) photons. We present numerical estimates of the cross sections for present-day fixed target experiments and for a possible future electron ion collider.

We develop threshold resummation for single-particle inclusive cross sections in hadron-hadron collisions to the level of next-to-next-to-leading logarithm, up to full matching with two-loop hard functions. We define and calculate all one-loop soft functions for all partonic channels. This enables us to separate the hard and soft functions at one loop. Along with these results, the one-loop finite parts of jet functions are used to check that the full soft, collinear and virtual corrections are reproduced to one loop for all partonic reactions. We exhibit these NLO results explicitly. NLO expansions of the resummed cross section match the exact NLO results extremely well numerically, and two loop expansions result in substantial corrections over many kinematic configurations. Explicit results are given in Mellin moment space, and a number of options for generating resummed cross sections are discussed.