Single-top production with the POWHEG method
英文摘要:
We describe briefly the POWHEG method and present results for single-top s- and t-channel production at hadron colliders.
机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。
Emanuele Re
We describe briefly the POWHEG method and present results for single-top s- and t-channel production at hadron colliders.
机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。
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We present a next-to-leading order calculation of Higgs boson production in vector-boson fusion processes interfaced to shower Monte Carlo programs, implemented according to the POWHEG method.
We present a next-to-leading-order calculation of W/Z production interfaced to shower Monte Carlo, implemented according to the POWHEG method. Finite width effects, Z/gamma interference and angular correlations of decay products are included. A detailed comparison with MC@NLO and PYTHIA is carried out.
We present results for the next-to-leading order calculation of single-top Wt-channel production interfaced to Shower Monte Carlo programs, implemented according to the POWHEG method. A comparison with MC@NLO is carried out. Results obtained using the PYTHIA shower are also shown and the effect of typical cuts is briefly discussed.
We study the effects of gluon radiation in top pair production and their decays for e+e- annihilation at the ILC. To achieve this we apply the POWHEG method and interface our results to the Monte Carlo event generator Herwig++. We consider a center-of-mass energy of 500GeV and compare decay correlations and bottom quark distributions before hadronization.
We present an implementation of the next-to-leading order hadronic production of a W boson in association with a pair of massive bottom quarks in the framework of POWHEG, a method to consistently interface NLO QCD calculations with shower Monte Carlo generators. The process has been implemented using the POWHEG BOX, an automated computer code that sistematically applies the POWHEG method to NLO QCD calculations. Spin correlations in the decay of the W boson into leptons have been taken into account using standard approximated techniques. We present phenomenological results for W b bbar-> l nu …
We present an implementation of the next-to-leading order vector boson plus one jet production process in hadronic collision in the framework of POWHEG, which is a method to implement NLO calculations within a Shower Monte Carlo context. All spin correlations in the vector boson decay products have been taken into account. The process has been implemented in the framework of the POWHEG-BOX, an automated computer code for turning a NLO calculation into a shower Monte Carlo program. We present phenomenological results for the case of the Z/gamma plus one jet production process, obtained by match…
We study the effects of gluon radiation in top pair production and their decays for e+e- annihilation at the ILC. To achieve this we apply the POWHEG method and interface our results to the Monte Carlo event generator Herwig++. We consider a center-of-mass energy of \sqrt{s}=500 GeV and compare decay correlations and bottom quark and anti-quark distributions before hadronization.
We present an implementation of the calculation of the production of W^+W^+ plus two jets at hadron colliders, at next-to-leading order (NLO) in QCD, in the POWHEG framework, which is a method that allows the interfacing of NLO calculations to shower Monte Carlo programs. This is the first 2 -> 4 process to be described to NLO accuracy within a shower Monte Carlo framework. The implementation was built within the POWHEGBOX package. We discuss a few technical improvements that were needed in the POWHEGBOX to deal with the computer intensive nature of the NLO calculation, and argue that further …
We present the matching of the next-to-leading order QCD calculation for W+W+jj production via vector-boson fusion in hadronic collisions to parton-shower Monte-Carlo programs according to the POWHEG method. Our implementation complements existing code for QCD-induced W+W+jj production in the POWHEGBOX package, thereby providing a platform for the complete Standard Model production of W+W+jj events via QCD and electroweak interactions. The impact of parton-shower effects is discussed for various distributions and found to be small in most cases. However, few observables, that are relevant for …
We present a next-to-leading order calculation of single-top production interfaced to Shower Monte Carlo programs, implemented according to the POWHEG method. A detailed comparison with MC@NLO and PYTHIA is carried out for several observables, for the Tevatron and LHC colliders.
We present a calculation of prompt photon and associated photon-jet production at next-to-leading order that is consistently matched to parton showers with POWHEG. Specific issues that appear in photon radiation are discussed. Numerical results are compared to pp collision data at RHIC energies and shown to describe the data better than inclusive next-to-leading order calculations or those with leading order Monte Carlo generators like PYTHIA alone.
We present results for the QCD production of Z/γ + 2 jets matched with parton showers using the POWHEG method. Some technicalities relevant for the merging of NLO corrections for this process with parton showers are discussed, and results for typical distributions are shown, in presence of different sets of cuts. A comparison with ATLAS data is also presented, and good agreement is found.
I review recent developments in POWHEG, a method for interfacing parton-shower generators with NLO QCD computations. I illustrate recent progress in understanding several features of the method, and in clarifying similarity and differences with respect to MC@NLO. Furthermore, I briefly describe a recently introduced framework, the POWHEG BOX, that allows the automatic POWHEG implementation of any given NLO calculation, and has been recently applied to Z+jet production and to Higgs production via vector-boson fusion.
Prompt photon production with two jets in POWHEG
本文在POWHEG框架下计算次领头阶瞬发光子伴随双喷注产生,并匹配PYTHIA与HERWIG部分子簇射,验证其与ATLAS数据及次次领头阶计算的一致性。
We present results from the analytic calculation of top+antitop+Higgs hadronic production at Next-to-Leading Order in QCD interfaced with parton-shower Monte Carlo event generators in the POWHEG BOX framework. We consider kinematic distributions of the top quark and Higgs boson at the 8 TeV Large Hadron Collider and study the theoretical uncertainties due to specific choices of renormalization/factorization scales and parton-showering algorithms, namely PYTHIA and HERWIG. The importance of spin-correlations in the production and decay stages of a top/antitop quark is discussed on the example o…
We present an implementation of the next-to-leading order dijet production process in hadronic collisions in the framework of POWHEG, which is a method to implement NLO calculations within a shower Monte Carlo context. In constructing the simulation, we have made use of the POWHEG BOX toolkit, which makes light of many of the most technical steps. The majority of this article is concerned with the study of the predictions of the Monte Carlo simulation. In so doing, we validate our program for use in experimental analyses, elaborating on some of the more subtle features which arise from the int…
We review the key features of POWHEG, a method for interfacing parton-shower Monte Carlo generators to fixed next-to-leading order QCD computations. We describe a recently introduced framework, the POWHEG-BOX, that allows the automatic POWHEG implementation of any given NLO calculation. We present a few results for Higgs boson production via vector boson fusion and Z + 1 jet production, both processes available in the POWHEG-BOX.
We consider the gluon fusion production cross section of a scalar Higgs boson at NLO QCD in the SM and in the MSSM. We implement the calculation in the POWHEG approach, and match the NLO-QCD results with the PYTHIA and HERWIG QCD parton showers. We discuss a few representative scenarios in the SM and MSSM parameter spaces, with emphasis on the fermion and squark mass effects on the Higgs boson distributions.
We present a next-to-leading order calculation of Higgs boson production via gluon fusion interfaced to shower Monte Carlo programs, implemented according to the POWHEG method. A detailed comparison with MC@NLO and PYTHIA is carried out for several observables, for the Tevatron and LHC colliders. Comparisons with next-to-next-to-leading order results and with resummed ones are also presented.
In this short note we discuss the origin of spikes in physical distributions in dijet production, originating after the Monte Carlo shower of POWHEG Les Houches events. We introduce a refinement of the way in which the POWHEG BOX separates the singular regions that reduces the appearance of spikes in the computed distributions. We also study the sensitivity of the results due to a modification of the way the POWHEG events are passed to the shower Monte Carlo program. We recommend that the new features should be used always in dijet production.
A POWHEG generator for di-jet production in polarized proton-proton collisions
本文提出了一种基于POWHEG框架的新生成器,用于模拟极化质子-质子碰撞中双喷注产生过程,并评估部分子喷注对实验数据的一致性影响。
As part of the DESY summer student program 2021, transverse momentum dependent (TMD) parton distributions obtained from the Parton Branching (PB) method were combined with next-to-leading-order (NLO) using the POWHEG method. Computations of the resulting Drell-Yan (DY) transverse momentum spectrum were performed. A good agreement of the theoretical predictions with the measurement performed by the CMS experiment at the center-of-mass energy of 13 TeV is found, at low and intermediate DY $p_{\rm T}$. The new scale choice option for the matching has been included in the CASCADE event generator.
In this article we generalise POWHEG next-to-leading order parton shower (NLOPS) simulations of vector boson production and vector boson production in association with a single jet, to give matrix element corrected MENLOPS simulations. In so doing we extend and provide, for the first time, an exact and faithful implementation of the MENLOPS formalism in hadronic collisions. We also consider merging the resulting event samples according to a phase space partition defined in terms of an effective jet clustering scale. The merging scale is restricted such that the component generated by the assoc…
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Higgs boson pair production at NLO in the POWHEG approach and the top quark mass uncertainties
本文在POWHEG-BOX框架下实现了包含完整顶夸克质量依赖的希格斯玻色子对产生次领头阶蒙特卡洛计算,并系统研究了顶夸克质量重整化方案及三线性自耦合变化带来的不确定性。
The hadronic production of a Higgs boson (H) in association with b jets will play an important role in investigating the Higgs-boson couplings to Standard Model particles during Run II of the CERN Large Hadron Collider, and could in particular reveal the presence of anomalies in the assumed hierarchy of Yukawa couplings to the third-generation quarks. A very high degree of accuracy in the theoretical description of this process is crucial to implement the rich physics program that could lead to either direct or indirect evidence of new physics from Higgs-boson measurements. Aiming for accuracy…
We present an implementation of the production of three jets at NLO plus parton-shower effects in the POWHEG BOX. Using the recently introduced MiNLO procedure for setting the renormalization and factorization scales, we are able to obtain a generator that is also well behaved when the third jet becomes unresolved. We compare key distributions computed at the NLO level, at the level of the POWHEG hard emission and after full shower by PYTHIA, Pythia8 and HERWIG6. We also compare our three-jet generator with the already available dijet POWHEG generator.
The aim of this work is to describe in detail the POWHEG method, first suggested by one of the authors, for interfacing parton-shower generators with NLO QCD computations. We describe the method in its full generality, and then specify its features in two subtraction frameworks for NLO calculations: the Catani-Seymour and the Frixione-Kunszt-Signer approach. Two examples are discussed in detail in both approaches: the production of hadrons in e+e- collisions, and the Drell-Yan vector-boson production in hadronic collisions.
In this paper we deal with radiation from heavy quarks in the context of next-to-leading order calculations matched to parton shower generators. A new algorithm for radiation from massive quarks is presented that has considerable advantages over the one previously employed. We implement the algorithm in the framework of the ${\tt POWHEG-BOX}$, and compare it with the previous one in the case of the ${\tt hvq}$ generator for bottom production in hadronic collisions, and in the case of the ${\tt bb4l}$ generator for top production and decay.
We present an implementation of the vector boson pair production processes ZZ, W+W- and WZ within the POWHEG BOX V2. This implementation, derived from the POWHEG BOX version, has several improvements over the old one, among which the inclusion of all decay modes of the vector bosons, the possibility to generate different decay modes in the same run, speed optimization and phase space improvements in the handling of interference and singly resonant contributions.
We present a new Monte Carlo event generator for the hadronic production of four top quarks in the POWHEG BOX framework. Besides the dominant next-to-leading order QCD corrections at $\mathcal{O}(α_s^5)$ we also include all subleading electroweak productions channels at leading-order accuracy. We validate our theoretical predictions by comparing to parton-shower matched predictions obtained within the MC@NLO framework for stable top quarks. Furthermore, we investigate in detail the various sources of theoretical uncertainties. Finally, we investigate a single lepton plus jets signature to stud…
We present a next-to-leading order calculation of Higgs boson production plus one and two jets via gluon fusion interfaced to shower Monte Carlo programs, implemented according to the POWHEG method. For this implementation we have used a new interface of the POWHEG BOX with MadGraph4, that generates the codes for generic Born and real processes automatically. The virtual corrections have been taken from the MCFM code. We carry out a simple phenomenological study of our generators, comparing them among each other and with fixed next-to-leading order results.
We present a calculation of direct photon production at next-to-leading order of QCD and a matching of this calculation with parton showers using POWHEG BOX. Based on simulations with POWHEG+PYTHIA, we perform a detailed phenomenological analysis of PHENIX data on prompt photon production and photon-hadron jet correlations in pp collisions at RHIC, considerably improving the description of these data with respect to previous calculations, and we suggest additional interesting analyses.
We present results for the QCD next-to-leading order (NLO) calculation of single-top t-channel production in the 4-flavour scheme, interfaced to Parton Shower (PS) Monte Carlo programs according to the POWHEG and MC@NLO methods. Comparisons between the two methods, as well as with the corresponding process in the 5-flavour scheme are presented. For the first time results for typical kinematic distributions of the spectator-b jet are presented in an NLO+PS approach.
We discuss the Standard Model Effective Field Theory (SM-EFT) contributions to neutral- and charge-current Drell-Yan production, associated production of the Higgs and a vector boson, and Higgs boson production via vector boson fusion. We consider all the dimension-six SM-EFT operators that contribute to these processes at leading order, include next-to-leading order QCD corrections, and interface them with parton showering and hadronization in Pythia8 according to the POWHEG method. We discuss existing constraints on the coefficients of dimension-six operators and identify differential and an…
We present an implementation for slepton pair production at hadron colliders in the POWHEG BOX, a framework for combining next-to-leading order QCD calculations with parton-shower Monte-Carlo programs. Our code provides a SUSY Les Houches Accord interface for setting the supersymmetric input parameters. Decays of the sleptons and parton-shower effects are simulated with PYTHIA. Focussing on a representative point in the supersymmetric parameter space we show results for kinematic distributions that can be observed experimentally. While next-to-leading order QCD corrections are sizable for all …
Recent progress in calculating lepton density functions inside the proton and simulating lepton showers laid the foundations for precision studies of resonant leptoquark production at hadron colliders. Direct quark-lepton fusion into a leptoquark is a novel production channel at the LHC that has the potential to probe a unique parameter space for large masses and couplings. In this work, we build the first Monte Carlo event generator for a full-fledged simulation of this process at NLO for production, followed by a subsequent decay using the POWHEG method and matching to the parton showers uti…
We present an implementation of the vector boson pair production processes ZZ, W+W- and W Z within the POWHEG framework, which is a method that allows the interfacing of NLO calculations to shower Monte Carlo programs. The implementation is built within the POWHEG BOX package. The Z/γ^* interference, as well as singly resonant contributions, are properly included. We also considered interference terms arising from identical leptons in the final state. As a result, all contributions leading to the desired four-lepton system have been included in the calculation, with the sole exception of the i…
We present an implementation of $t\bar t \ell^+\ell^-$ ($\ell=e,μ$) hadronic production at next-to-leading order in QCD matched to parton-shower event generators in the POWHEG BOX framework. The program we developed includes all leading-order contributions of order $α_s^2α^2$ for the specified final state, as well as the corresponding first-order QCD corrections. Decays of the top quarks have been simulated retaining spin-correlations in all tree-level matrix elements. We consider the case of the Large Hadron Collider at $\sqrt{s}=13$ TeV and compare results for $t\bar t \ell^+\ell^-$ producti…
We present a generator for the production of a Higgs boson H in association with a vector boson V=W or Z (including subsequent V decay) plus zero and one jet, that can be used in conjunction with general-purpose shower Monte Carlo generators, according to the POWHEG method, as implemented within the POWHEG BOX framework. We have computed the virtual corrections using GoSam, a program for the automatic construction of virtual amplitudes. In order to do so, we have built a general interface of the POWHEG BOX to the GoSam package. With this addition, the construction of a POWHEG generator within …
The associated production of charged Higgs bosons and top quarks at hadron colliders is an important discovery channel to establish the existence of a non-minimal Higgs sector. Here, we present details of a next-to-leading order (NLO) calculation of this process using the Catani-Seymour dipole formalism and describe its implementation in POWHEG, which allows to match NLO calculations to parton showers. Numerical predictions are presented using the PYTHIA parton shower and are compared to those obtained previously at fixed order, to a leading order calculation matched to the PYTHIA parton showe…
Measurements of $t\bar{t} H$ production in the $H\to b\bar{b}$ channel depend in a critical way on the theoretical uncertainty associated with the irreducible QCD $t\bar{t}+b$-jet background. We introduce a new $pp\to t\bar{t}b\bar{b}$ POWHEG generator in the 4F scheme based on POWHEG-BOX-RES and on OpenLoops for fast evaluation of the scattering amplitudes. We present predictions and uncertainties for $t\bar{t}+b$-jet observables at the 13 TeV LHC. We also consider theoretical uncertainties related to the POWHEG matching method and to the parton shower (PS) modelling, with emphasis on $g\to b…
We present a next-to-leading order plus parton-shower event generator for the production of a W boson plus two bottom quarks and a jet at hadron colliders, implemented in the POWHEG BOX framework. Bottom-mass effects and spin correlations of the decay products of the W boson are fully taken into account. The code has been automatically generated using the two available interfaces to MadGraph4 and GoSam, the last one updated to a new version. We have applied the MiNLO prescription to our Wbbj calculation, obtaining a finite differential cross section also in the limit of vanishing jet transvers…
We present a next-to-leading order (NLO) treatment of the production of a new charged heavy vector boson, generically called W', at hadron colliders via the Drell-Yan process. We fully consider the interference effects with the Standard Model W boson and allow for arbitrary chiral couplings to quarks and leptons. We present results at both leading order (LO) and NLO in QCD using the MC@NLO/Herwig++ and POWHEG methods. We derive theoretical observation curves on the mass-width plane for both the LO and NLO cases at different collider luminosities. The event generator used, Wpnlo, is fully custo…
We present the calculation of the NLO QCD corrections to the electroweak production of top-antitop pairs at the CERN LHC in the presence of a new neutral gauge boson. The corrections are implemented in the parton shower Monte Carlo program POWHEG. Standard Model (SM) and new physics interference effects are properly taken into account. QED singularities, first appearing at this order, are consistently subtracted. Numerical results are presented for SM and $Z'$ total cross sections and distributions in invariant mass, transverse momentum, azimuthal angle and rapidity of the top-quark pair. The …
We present the implementation of Higgs boson pair production in gluon fusion within a non-linear Effective Field Theory framework containing five anomalous couplings for this process. The code, available within the POWHEG-BOX-V2, includes full NLO QCD corrections with massive top quarks. All five couplings can be modified by the user. We show $m_{hh}$ distributions at seven benchmark points provided by an $m_{hh}$ shape analysis at NLO and showered $p_T^{hh}$ distributions resulting from an interface to Pythia-8 and Herwig-7.2.
We present a fully consistent implementation of electroweak and strong radiative corrections to single W hadroproduction in the POWHEG BOX framework, treating soft and collinear photon emissions on the same ground as coloured parton emissions. This framework can be easily extended to more complex electroweak processes. We describe how next-to-leading order (NLO) electroweak corrections are combined with the NLO QCD calculation, and show how they are interfaced to QCD and QED shower Monte Carlo. The resulting tool fills a gap in the literature and allows to study comprehensively the interplay o…
We present a new Monte Carlo event generator for the production of a top-quark pair in association with a $W^\pm$ boson at hadron colliders in the POWHEG-BOX framework. We consider the next-to-leading-order QCD corrections to the $pp\to t\bar{t} W^\pm$ cross section, corresponding to the $\mathcal{O}(α_s^3α)$ and $\mathcal{O}(α_sα^3)$ terms in the perturbative expansion of the parton-level cross section, and model the decays of $W$ and top quarks at leading order retaining spin correlations. The fixed-order QCD calculation is further interfaced with the Pythia8 parton-shower event generator vi…
NLL/NLO$^-$ studies on Higgs-plus-jet production with POWHEG+JETHAD
本文针对LHC上希格斯玻色子与轻味喷流大快度间隔伴随产生的半硬过程,提出将POWHEG的NLO固定阶计算与JETHAD的NLL能量对数重求和相结合的匹配方法原型。
We detail a calculation of W gamma production in hadronic collision, at Next-to-Leading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO pro…
NLO + parton-shower generator for Wc production in the POWHEG BOX RES
本文在POWHEG BOX RES中实现W伴随粲夸克产生的NLO+部分子簇射模拟,精确处理离壳、自旋关联及非对角CKM效应,并结合Herwig与Pythia同CMS 13 TeV数据比较。
We describe how a simulation of Higgs boson production accurate at next-to-next-to-leading order and matched to a parton shower can be built by combining the POWHEG and MiNLO methods and using HNNLO results as input.
We study the theoretical uncertainties in the determination of the top-quark mass using next-to-leading-order (NLO) generators, that describe the top-quark decay at different levels of accuracy, interfaced to parton showers (PS). Specifically we consider one generator that implements NLO corrections only in the production dynamics, one that also takes them into account in the top-quark decay in the narrow width approximation (NWA) and one that implements them exactly, including finite-width and interference effects. We aim at assessing the errors in top-mass determinations of purely theoretica…
We present the status of the automation of NLO processes within the event generator WHIZARD. The program provides an automated FKS subtraction and phase space integration over the FKS regions, while the (QCD) NLO matrix element is accessed via the Binoth Les Houches Interface from an externally linked one-loop program. Massless and massive test cases and validation are shown for several e+e- processes. Furthermore, we discuss work in progress and future plans. The second part covers the matching of the NRQCD prediction with NLL threshold resummation to the NLO continuum top pair production at …
The precision measurement of the mass of the $W$ boson is an important goal of the Fermilab Tevatron and the CERN Large Hadron Collider (LHC). It requires accurate theoretical calculations which incorporate both higher-order QCD and electroweak corrections, and also provide an interface to parton-shower Monte Carlo programs which make it possible to realistically simulate experimental data. In this paper, we present a combination of the full ${\cal O}(α)$ electroweak corrections of {\tt WGRAD2}, and the next-to-leading order QCD radiative corrections to $W\to\ellν$ production in hadronic colli…
We review recent theoretical improvements of Monte Carlo event generators for top-quark pair production and decay at the LHC based on the POWHEG method. We present an event generator that implements spin correlations and off-shell effects in top-decay chains described in terms of exact matrix elements for $pp\to \ell^+ν_{\ell}\, l^-\barν_{l} \,b \,\bar b$ at order $α^4 α_s^2$, including full NLO QCD corrections and interference effects with single-top and non-resonant topologies yielding to the same final state. We then compare its predictions to previous generators that implement NLO correcti…
A Powheg generator for $t$- and $s$-channel single-top production and decay including non-resonant effects
本文提出一个基于POWHEG BOX RES的次领头阶+部分子簇射生成器,用于强子对撞机中$t$道和$s$道单顶产生与轻子衰变,包含离壳和非共振效应,并匹配Pythia以结合五味计算与底夸克质量效应。
After the discovery of a Higgs boson in 2012 at the CERN Large Hadron Collider (LHC) the detailed study of its properties, and most importantly its couplings to other particles, has started. This is a very important task to be completed, in particular to test whether it is indeed the Higgs boson predicted by the Standard Model (SM). The precise study of the Higgs couplings to gauge bosons is of particular importance and requires as much information as possible. In this view this paper provides the next-to-leading order (NLO) QCD corrections to the production cross sections and differential dis…
The study of the Higgs boson properties is one of the most important tasks to be accomplished in the next years, at the Large Hadron Collider (LHC) and at future colliders such as the Future Circular Collider in hadron-hadron mode (FCC-hh), the potential 100 TeV follow-up of the LHC machine. In this view the precise study of the Higgs couplings to weak gauge bosons is crucial and requires as much information as possible. After the recent calculation of the next-to-leading order QCD corrections to the production cross sections and differential distributions of a Standard Model Higgs boson in as…
We present a study of Higgs hadroproduction through vector-boson fusion at the NLO in QCD matched with parton showers. We discuss the matching systematics affecting this process through a comparison of the aMC@NLO predictions with the POWHEG and the pure-NLO ones.
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