Driving missing data at the LHC: NNLO predictions for the ratio ofγ+jandZ+j

Abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Driving missing data at the LHC: NNLO predictions for the ratio of γ + j and Z + j In this paper, we present a calculation of the γ þ j process at next-to-next-to-leading order (NNLO) in QCD and compare the resulting predictions to 8 TeV CMS data. We find good agreement with the shape of the photon p T spectrum, particularly after the inclusion of additional electroweak corrections, but there is a tension between the overall normalization of the theoretical prediction and the measurement. We use our results to compute the ratio of Zð→l þ l − Þ þ j to γ þ j events as a function of the vector boson transverse momentum at NNLO, a quantity that is used to normalize Zð→ννÞ þ j backgrounds in searches for dark matter and supersymmetry. Our NNLO calculation significantly reduces the theoretical uncertainty on this ratio, thus boosting its power for future searches of new physics.

Precise predictions for $$V+$$ V + jets dark matter backgrounds

“…For a consistency treatment of O(α) effects in the PDFs, the LUXqed_plus_PDF4LHC15_nnlo distributions should be used in all photon-, quark-, and gluon-induced channels. 16 Photon-induced effects are negligible in Z + jet and γ + jet production, but their impact on pp → W + jet, and thus on the W/Z and W/γ ratios, can reach the 5% level at the TeV scale 17 (see Fig. 12).…”

“…The NNLO QCD prediction for the pp → γ +jet process is based on the calculations of Refs. [15,16] and has been obtained using MCFM [62]. In order to ensure the correctness of the numerical implementation of cuts and other parameters in the NNLO codes, a detailed comparison has been performed at the level of the NLO QCD results as described above.…”

“…For our analysis we shall use the most up-to-date theoretical predictions available today for the description of vector-boson production at large p T . On the QCD side, we rely on the next-tonext-to-leading order (NNLO) calculations, which appeared recently for Z +jet [8][9][10][11][12], W +jet [13,14] and γ +jet [15,16] production. On the EW side, we apply full NLO calculations for Z +jet [17][18][19], W +jet [19,20] and γ +jet [21] production with off-shell decays of the Z and W bosons.…”

H + 1 jet production revisited

“…In this paper we will always use the choice P i = 2E i , resulting in a so-called geometric measure [27,28]. However, we will define T 1 both in the hadronic center-of-mass frame (as in previous 1-jettiness calculations performed using MCFM [15][16][17][29][30][31]) as well as in a boosted frame in which the system consisting of the Higgs boson and the jet is at rest. As explained in, for instance, Refs.…”

N -jettiness subtractions for gg→H at subleading power

“…N-jettiness subtractions provide a powerful and simple method that is in principle applicable for an arbitrary number of jets in the final state. They have been applied to W=Z=H=γ þ jet at NNLO [7,[11][12][13][14], as well as inclusive photon production [15], and have been implemented in MCFM8 for colorsinglet production [16][17][18][19]. They have also been used to calculate single-inclusive jet production in ep collisions at NNLO [20].…”