We present a detailed derivation of the power corrections to the factorization theorem for the 0-jettiness event shape variable T . Our calculation is performed directly in QCD without using the formalism of effective field theory. We analytically calculate the next-to-leading logarithmic power corrections for small T at next-to-leading order in the strong coupling constant, extending previous computations which obtained only the leading-logarithmic power corrections. We address a discrepancy in the literature between results for the leading-logarithmic power corrections to a particular definition of 0-jettiness. We present a numerical study of the power corrections in the context of their application to the N-jettiness subtraction method for higher-order calculations, using gluon-fusion Higgs production as an example. The inclusion of the next-to-leading-logarithmic power corrections further improves the numerical efficiency of the approach beyond the improvement obtained from the leading-logarithmic power corrections.
We discuss the uncertainty on processes computed using next-to-next-to leading (NNLO) parton distributions (PDFs) due to the neglect of higher order perturbative corrections in the PDF determination, in the specific case of Higgs production in gluon fusion. By studying the behaviour of the perturbative series for this process, we show that this uncertainty is negligible in comparison to the theoretical uncertainty on the matrix element. We then take this as a case study for the use of the Cacciari-Houdeau method for the estimate of theoretical uncertainties, and show that the method provides an effective way of treating theoretical uncertainties on the matrtix element and the PDF on the same footing. We briefly discuss the possible generalization of these results to other processes, and in particular top production.
We discuss the subleading power corrections to one-jet production processes in N -jettiness subtraction using vector-boson plus jet production as an example. We analytically derive the next-to-leading power leading logarithmic corrections (NLP-LL) through O(α S ) in perturbative QCD, and outline the calculation of the next-to-leading logarithmic corrections (NLP-NLL). Our result is differential in the jet transverse momentum and rapidity, and in the vector boson momentum squared and rapidity. We present simple formulae that separate the NLP corrections into universal factors valid for any one-jet cross section and process-dependent matrix-element corrections. We discuss in detail features of the NLP corrections such as the process independence of the leading-logarithmic result that occurs due to the factorization of matrix elements in the subleading soft limit, the occurrence of poles in the non-hemisphere soft function at NLP and the cancellation of potential T 1 /Q corrections to the N -jettiness factorization theorem. We validate our analytic result by comparing them to numerically-fitted coefficients, finding good agreement for both the inclusive and the differential cross sections.arXiv:1907.12213v2 [hep-ph] 6 Aug 2019 separate the power corrections into process-independent terms valid for any one-jet production process and process-dependent matrix element correction factors. Important aspects of our results are summarized below.• We make use of the expansion by regions [32,33] to perform the computation of the cross section. In particular, we split the phase space into two beam regions, a jet region and a soft region.• We show that all NLP-LL corrections at NLO arise from the emission of soft partons, as in the case of color-singlet production [1, 2], and show how to obtain such subleading soft corrections by making use of the subleading soft theorem [34]. This allows us to write the NLP-LL result in a universal form valid for all one-jet processes.• We show that the non-hemisphere soft contributions defined in [35], which are finite at leading power, contribute to poles when extended to next-to-leading power. These poles are necessary for the consistency of the result at NLP.• We demonstrate the cancellation of potential power corrections suppressed only by T /Q, where T is the one-jettiness event shape variable and Q is a generic hard scale.Our paper is organized as follows. In Section II we discuss the Born-level process for V + j production and introduce the notation used in the remainder of the manuscript. We discuss our strategy for the computation of the NLP corrections in Section III, and illustrate the separation of the phase space into different regions. In Section IV, we write down a general expression for the phase space that is valid in every region, separating the case where the two final-state partons are measured as two separate jets from the case where they are part of the same jet.We then proceed to expand the phase space in each region, listing all the relevant expansion coefficients in t...
At the Fermilab Tevatron proton-antiproton (p p) collider, high-mass electron-neutrino (eν) pairs are produced predominantly in the process p p → Wð→ eνÞ þ X. The asymmetry of the electron and positron yield as a function of their pseudorapidity constrain the slope of the ratio of the uto d-quark parton distributions versus the fraction of the proton momentum carried by the quarks. This paper reports on the measurement of the electron-charge asymmetry using the full data set recorded by the Collider Detector at Fermilab in 2001-2011 and corresponding to 9.1 fb −1 of integrated luminosity. The measurement significantly improves the precision of the Tevatron constraints on the parton-distribution functions of the proton. Numerical tables of the measurement are provided.
At the Fermilab Tevatron proton-antiproton (pp) collider, high-mass electron-neutrino (eν) pairs are produced predominantly in the process pp → W (→ eν) + X. The asymmetry of the electron and positron yield as a function of their pseudorapidity constrain the slope of the ratio of the u-to dquark parton distributions versus the fraction of the proton momentum carried by the quarks. This paper reports on the measurement of the electron-charge asymmetry using the full data set recorded by the Collider Detector at Fermilab in 2001-2011 and corresponding to 9.1 fb −1 of integrated luminosity. The measurement significantly improves the precision of the Tevatron constraints on the parton-distribution functions of the proton. Numerical tables of the measurement are provided.
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