REVIEW
NNLO QCD corrections to the Higgs-strahlung processes at hadron colliders
High Energy Physics - Phenomenology · Submitted 16 Jul 2003 · 31 references
Pith's verdict: The standard NNLO reference for Higgs-strahlung, and it holds up — just don't quote the 2–3% theory error as if it were derived rather than inferred from scale variation.
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Referee report
The paper
The paper claims
The Higgs-strahlung channel is now a few-percent prediction, not a tens-of-percent one.
The reading
What carries the argument
The load-bearing device is the factorization identity of Eq. (5), $dhatsigma/dk^2(pp to HV + X) = sigma(pp to V^* + X) times dGamma/dk^2(V^* to HV)$, which splits the process into a piece governed purely by QCD (off-shell vector-boson production, known to NNLO) and a piece governed by electroweak kinematics (the splitting of the virtual boson into a real boson plus the Higgs). This is what lets the authors import the two-loop Drell–Yan calculation rather than perform a new multi-scale NNLO computation. The second ingredient is the set of quark-loop amplitudes for $gg to HZ$ — a triangle with $Z^* to HZ$ and box diagrams with both $H$ and $Z$ emitted from the internal quark lines — which interfere destructively and are evaluated with the full $m_t$, $m_b$ dependence. The third is the use of NNLO-evolved parton densities, which at the time required approximate three-loop splitting functions, supplied by the MRST sets.
Extended reading notes
Core claim
The central claim is that the QCD corrections to $pp to HV$ are known through $O(alpha_s^2)$ and are small, so the channel becomes one of the theoretically cleanest Higgs production modes at hadron colliders. The authors obtain this by factorizing the hadronic cross section as the Drell–Yan cross section for $pp to V^*$ times the energy distribution $dGamma/dk^2(V^* to HV)$, so that the known two-loop Drell–Yan result transfers directly. For $Z$ final states they add the heavy-quark loop processes, principally $gg to HZ$, computed with full top and bottom mass dependence, and they argue that the $Zgg$-induced corrections to $qbar q to Z^*$ are negligible (below the percent level at the Tevatron and smaller at the LHC). Numerically, with scales fixed at $mu_F = mu_R = M_{HV}$ and matched-order MRST parton densities, the NLO $K$-factor is about 1.27–1.29 at the LHC and 1.30–1.35 at the Tevatron, and the NNLO corrections add only about 1–3.5% at the LHC and about 10% at the Tevatron. The scale-variation band shrinks from roughly 10% (LO) to 5% (NLO) to 2% (NNLO) at the LHC for $M_H = 120$ GeV, and from 20% to 7% to 3% at the Tevatron. The $gg to HZ$ subprocess is found to contribute around 10% of the total $HZ$ rate at the LHC for low Higgs masses and to be negligible at the Tevatron.
Load-bearing premise
The whole NNLO result is inherited through the factorization of Eq. (5), which the authors themselves note in footnote 2 holds only at first order in the electroweak coupling, so QCD corrections to the $V^* to HV$ splitting and final state are neglected.
Editorial extensions
If this is right
- The residual QCD uncertainty on $pp to HW$ and $pp to HZ$ falls to 2–3%, below the roughly 5% parton-distribution error quoted at NLO, so PDFs and luminosity become the dominant theoretical limitation.
- Because the $K$-factor is large and nearly constant in $M_H$, a measured Higgs-strahlung rate can be converted into a determination of the $HVV$ coupling with a small and slowly varying QCD correction.
- At the LHC, the $gg to HZ$ channel must be included for low Higgs masses at the 10% level of the total $HZ$ rate, but can be dropped at the Tevatron where it stays at the fraction-of-a-femtobarn level.
- The NNLO corrections are of the same order as the electroweak $O(alpha)$ corrections but of opposite sign, so the two must be combined before quoting a final theory error.
- The same factorization argument extends to supersymmetric Higgs-strahlung $pp to VPhi$ and to the associated $Phi A$ production channel, up to global coupling factors and an additional one-loop $gg to Phi A$ piece.
Reading between the lines
- If the QCD error really sits at 2–3%, the practical bottleneck for using Higgs-strahlung as a coupling measurement shifts to the integrated luminosity, which the authors elsewhere estimate at about 5%; a luminosity calibration from $W$ and $Z$ Drell–Yan would then be the natural next step, since much of the $K$-factor cancels in the ratio.
- The paper's own logic suggests a sharper test of the factorization ansatz than any cross-section measurement: a dedicated calculation of the $O(alpha_s^2)$ corrections to the $V^* to HV$ splitting itself, which would either confirm that the final-state QCD corrections are negligible or move the quoted precision.
- The same Drell–Yan factorization could be pushed to the $b bar b to H$ channel or to charged-Higgs associated production, where the final-state QCD corrections are less obviously small and the ansatz would be under more stress.
- Because the $gg to HZ$ box and triangle amplitudes interfere destructively and depend on the top mass, a measurement of the $HZ$ rate at high $M_H$ would be sensitive to the sign and size of that interference, giving a handle that the inclusive $qbar q$ channel does not provide.
Original abstract
We implement, at next-to-next-to-leading order, the QCD corrections to Standard Model Higgs boson production in association with vector bosons at hadron colliders, $q\bar{q} \to HV$ with $V=W,Z$. They consist of the two--loop corrections to the Drell--Yan process for the production of off-shell vector bosons, $q\bar{q} \to V^*$, and in the case of $Z$ final states, of the additional contribution from heavy-quark loop mediated processes, in particular $gg \to HZ$. For the Higgs boson masses relevant at the Tevatron and the LHC, $M_H \lsim 200$--300 GeV, the two-loop corrections are small, increasing the production cross sections by less than 5% and 10%, respectively; the scale dependence is reduced to a level of less than a few per cent. This places these processes among the most theoretically clean Higgs boson production channels at hadron colliders.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We implement, at next-to-next-to-leading order, the QCD corrections to Standard Model Higgs boson production in association with vector bosons at hadron colliders, $q\bar{q} \to HV$ with $V=W,Z$. They consist of the two--loop corrections to the Drell--Yan process for the production of off-shell vector bosons, $q\bar{q} \to V^*$, and in the case of $Z$ final states, of the additional contribution from heavy-quark loop mediated processes, in particular $gg \to HZ$. For the Higgs boson masses relevant at the Tevatron and the LHC, $M_H \lsim 200$--300 GeV, the two-loop corrections are small, increasing the production cross sections by less than 5% and 10%, respectively; the scale dependence is reduced to a level of less than a few per cent. This places these processes among the most theoretically clean Higgs boson production channels at hadron colliders.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We implement, at next-to-next-to-leading order, the QCD corrections to Standard Model Higgs boson production in association with vector bosons at hadron colliders, $q\bar{q} \to HV$ with $V=W,Z$. | contribution 1.00 | 0.95 | 0.08 | asserted 0.99 |
| s1 | They consist of the two--loop corrections to the Drell--Yan process for the production of off-shell vector bosons, $q\bar{q} \to V^*$, and in the case of $Z$ final states, of the additional contribution from heavy-quark loop mediated processes, in particular $gg \to HZ$. | contribution 0.65 | 0.62 | 0.05 | asserted 1.00 |
| s2 | For the Higgs boson masses relevant at the Tevatron and the LHC, $M_H \lsim 200$--300 GeV, the two-loop corrections are small, increasing the production cross sections by less than 5% and 10%, respectively; the scale dependence is reduced to a level of less than a few per cent. | result 1.00 | 0.90 | 0.50 | asserted 1.00 |
| s3 | This places these processes among the most theoretically clean Higgs boson production channels at hadron colliders. | interpretation 1.00 | 0.64 | 0.51 | asserted 1.00 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
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- C citations
- R cross-paper relations
Figures
Figures reproduced from arXiv:hep-ph/0307206 by the authors.
References
How the literature uses it
130 arXiv papers cite this in 148 sentences
Papers citing it · 67 sentences without a confident label
Builds on it 1 paper
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In order to translate the SM results [ref] to the case of $gg→Zϕ$ with $ϕ=h^0,H^0$ in the MSSM, it is not sufficient to adjust the $HZZ$ and $Hqq$ couplings; it is also necessary to include certain quark triangle diagrams with an $A^0$ boson in the $s$ channel [see Fig. [ref](a)].
Associated production of Z and neutral Higgs bosons at the CERN Large Hadron Collider · Introduction · 0.88
Uses its method or tool 7 papers
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The NNLO-QCD corrections were obtained with VH@NNLO [ref] and the NLO-EW with Hawk [ref] .
Ad interim recommendations for the Higgs boson production cross sections at $\sqrt{s} = 13.6$ TeV · VH · 0.92
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For vector boson fusion and Higgs boson production in association with a weak boson, the SM predictions were determined using Powheg [ref] and each were scaled to the NNLO calculation with NLO electroweak corrections applied [ref] .
Angles on CP-violation in Higgs boson interactions · Theoretical framework · 0.88
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The rates for $W^±H$ and $Z H$ processes were estimated at NNLO [ref] inlcuding NLO EW corrections [ref] and top quark mass effects [ref] using the public package Vh@nnlo [ref] version 2.0.3.
Mono-Higgs Signature in the Scotogenic Model with Majorana Dark Matter · Phenomenological setup and Event selection · 0.93
Uses its data or values 48 papers
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The cross sections for the Higgs boson production mechanisms and decay branching fractions, together with their uncertainties, are taken from Ref. [ref] and are derived from Refs. [ref] .
Search for a fermiophobic Higgs boson in pp collisions at sqrt(s) = 7 TeV · Search channels · 1.00
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The cross sections for the Higgs boson production mechanisms and decay branching fractions, together with their uncertainties, are taken from Ref. [ref] and are derived from Refs. [ref] .
Combined results of searches for the standard model Higgs boson in pp collisions at sqrt(s) = 7 TeV · Introduction · 1.00
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Specifically, we calculate the SM4 signal cross sections by taking SM3 production cross sections for the different production mechanisms from [ref] (LHC) and [ref] (Tevatron), scaling them with corresponding SM4/SM3 ratios of related partial Higgs decay widths and multiplying with the SM4 branching fractions calculated by HDECAY.
Joint analysis of Higgs decays and electroweak precision observables in the Standard Model with a sequential fourth generation · Methodology · 0.80
Compares with it 3 papers
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At this order we may compare with the results of Ref. [ref] for most processes and for the remaining $W^±H$ and $ZH$ processes with the code vh@nnlo [ref] .
Non-local slicing approaches for NNLO QCD in MCFM · NNLO · 0.99
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As a test of our implementation, we have validated our calculation in the absence of any cuts on the final state particles by comparison with the public code vh@nnlo [ref] .
Associated production of a Higgs boson at NNLO · LHC Phenomenology · 0.99
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In this case a sizable destructive interference between the triangle and the box diagrams takes place [ref] , while this does not happen for VBF (see also the plots in fig:hqxsection).
Vector boson fusion at NNLO in QCD: SM Higgs and beyond · Quark-gluon initiated contributions via the square of one-loop diagrams · 0.94
Cites it as background 19 papers
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Higher-order QCD corrections for Higgs Strahlung via DY process can be found in [ref] .
Associated $ZH$ production in gluon fusion process at NLO+NLL · Introduction · 0.90
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At fixed-order accuracy, NNLO QCD corrections for the $V$ production mode have been available for some time [ref] .
$VH+\text{jet}$ production in hadron-hadron collisions up to order $\alpha_s^3$ in perturbative QCD · Introduction · 0.90
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Alternatively, the $ϕ$ bosons can be produced, with interesting rates, in association with (i) a dijet via intermediate-boson fusion, $qq^'→qq^'V^*V^*→qq^'ϕ$, where $q$ and $q^'$ stand for any light flavor of quark or antiquark, $V=W^±,Z$, and virtual particles are marked by an asterisk [ref] ; (ii) a quark-antiquark pair of heavy flavor $Q=t,b$ via $gg,qq̅→QQ̅ϕ$ [ref] ; (iii) an intermediate boson via $qq̅^'→W^±ϕ$ [ref] , $qq̅→Zϕ$ [ref] , and $gg→Zϕ$ [ref] ; or (iv) another, possibly different $ϕ$ boson via $qq̅→ϕ_1ϕ_2$ [ref] and $gg→ϕ_1ϕ_2$ [ref] .
Associated production of Z and neutral Higgs bosons at the CERN Large Hadron Collider · Introduction · 0.80
Discussion
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