Full one-loop electroweak corrections to e+e- to 3 jets at linear colliders
C. M. Carloni Calame, S. Moretti, F. Piccinini, D. A. Ross
备注：
6 pages, to appear in the proceedings of the workshop "LC09 -- e+e- Physics at the TeV scale and the Dark Matter Connection", 21-24 September 2009, Perugia (Italy). Minor corrections, references added.
We describe the impact of the full one-loop electroweak terms of O(alpha_s alpha_EM^3) entering the electron-positron into three-jet cross-section from sqrt(s)=M_Z to TeV scale energies. We include both factorisable and non-factorisable virtual corrections and photon bremsstrahlung. Their importance for the measurement of alpha_S from jet rates and shape variables is explained qualitatively and illustrated quantitatively, also in presence of b-tagging.
Prospects on electroweak physics at a future International Linear Collider (ILC) are summarized, including gauge coupling measurements, top quark physics and Higgs physics.
We present an implementation of the full electroweak $H+2~\text{jets}$ production process at hadron colliders in the framework of the $\tt{POWHEG~BOX}$, a public tool for the matching of fixed-order perturbative calculations with parton shower generators. Our implementation allows for the simultaneous description of vector-boson fusion and Higgsstrahlung contributions. NLO-QCD and electroweak corrections are taken into account and matched to QCD and QED showers, respectively. The size of the fixed-order QCD and electroweak corrections is found to be moderate, but dependent on the considered se…
We study the collider phenomenology of the electroweak phase transition and electroweak baryogenesis in the framework of the effective field theory. Our study shows that the effective theory using the dimension-6 operators can enforce strong first order phase transition and provide sizable CP violation to realize a successful electroweak baryogenesis. Such dimension-6 operators can induce interesting Higgs phenomenology that can be verified at colliders such as the LHC and the planning CEPC. We then demonstrate that this effective theory can originate from vector-like quarks and the triplet Hi…
The physics potential of a high-energy photon collider is reviewed. The emphasis is put on aspects related to the symmetry breaking sector, including Higgs searches and production of longitudinal vector bosons.
The International Linear Collider (ILC) will be able to precisely measure the electroweak couplings of the top in e+e- -> tt~. We compare the limits which can be achieved at the ILC with those which can be obtained in tt~gamma$ and tt~Z production at the Large Hadron Collider (LHC).
The interactions of electroweak gauge bosons are severely constrained by the symmetries inferred from low energy observables. The exploration of the dynamics of electroweak symmetry breaking requires therefore both an experimental sensitivity and a theoretical precision that is better than the natural scale of deviations from minimal extrapolations of the low energy effective theory. Some techniques for obtaining improved theoretical predictions for precision tests at a future e^+e^- linear collider are discussed.
We briefly review the recent developments of probing the electroweak symmetry breaking mechanism at high energy colliders such as the CERN LEP2, the Fermilab Tevatron, the CERN LHC and the e(+)e(-) linear colliders. Both weakly interacting and strongly interacting electroweak symmetry breaking mechanisms are concerned.
Recent developments in the field of complete electroweak tree-level calculations for six-fermion final states in e+ e- collisions are briefly reviewed. Particular attention is given to top-quark and Higgs boson physics, which are items of primary importance at the Next Linear Collider. The relevance of electroweak backgrounds and finite-width effects is discussed, showing the importance of complete calculations for precision studies at the colliders operating in the TeV energy range.
The manner in which the parameters of a two-Higgs-doublet model can be chosen so that no Higgs boson is discovered at a $\sqrt{s}\leq 800\gev$ $\epem$ collider, while maintaining consistency with current precision electroweak measurements, is described. The importance of a Giga-$Z$ factory and higher collider energies for such a scenario is emphasized.
We present results for the electroweak radiative corrections to the production of a leptonically decaying Z boson in association with two jets at the LHC. Tree-level and one-loop amplitudes have been obtained with the computer code Recola for the recursive generation of tree-level and one-loop amplitudes in the Standard Model. The one-loop integrals have been calculated with the tensor-integral library Collier. The electroweak corrections turn out to be small for inclusive cross sections but can become large in tails of distributions.
In this paper I review the calculations (and partially simulations and theoretical studies) that have been made and published during the last two to three years focusing on the electroweak symmetry breaking sector and the Higgs boson(s) within the Standard Model and models beyond the Standard Model (BSM) at or relevant for either the International Linear Collider (ILC) or the Compact Linear Collider (CLIC), commonly abbreviated as Linear Collider (LC).
Recent progress in calculating O(alpha) electroweak corrections to W+W- pair production in photon-photon collisions is reviewed. The potential of the Photon Linear Collider to study anomalous W couplings is discussed.
In this work we have studied the phenomenological properties at future e+e- linear colliders of two models of strong electroweak symmetry breaking, characterized by the presence of new spin one strong interacting resonances.
The current theoretical understanding of anomalous gauge boson couplings is reviewed, and the direct measurement of these couplings in present and future hadron collider experiments is briefly discussed.
This contribution summarizes some of the important theoretical progress that has been made in the arena of electroweak physics at hadron colliders. The focus is on developments that have sharpened theoretical predictions for final states produced through electroweak processes. Special attention is paid to new results that have been presented in the last year, since LHCP2015, as well as on key issues for future measurements at the LHC.
We sketch some of our recent studies on probing strongly interacting electroweak symmetry breaking mechanism at high energy colliders such as the CERN LHC and the future e(+)e(-) linear collider. The study includes both model-dependent and model-independent probes.
We report on our recent work on electroweak corrections to $t\bar{t}$ production at hadron colliders. Specifically, we discuss the weak-interaction contributions to the top quark transverse momentum and $t \bar{t}$ invariant mass distributions and an induced parity-violating top-spin asymmetry.
In this paper we present the results from a calculation of the full electroweak one-loop corrections for $γZ$ vector-boson pair production at hadron colliders. The cases of proton--antiproton as well as proton--proton collisions, at the Tevatron and the LHC, respectively, are considered. Results are presented for the distribution of the $γZ$ invariant mass and for the transverse momentum of the final-state photon. The higher-order electroweak effects are numerically significant, in particular for probing possible anomalous gauge-boson couplings.
We develop a precise power counting rule (a generalization of Weinberg's counting method for the nonlinear sigma model) for the electroweak theories formulated by chiral Lagrangians. Then we estimate the contributions of ``all'' next-to-leading order (NLO) bosonic operators to the amplitudes of the relevant scattering processes which can be measured at high energy colliders, such as the LHC and future Linear Colliders. Based upon these results, we globally classify the sensitivities of testing all NLO bosonic operators for probing the electroweak symmetry breaking mechanism at high energy coll…
We calculate the next-to-leading order electroweak corrections to the production of a photon pair in association with zero, one and two jets at the LHC. We use GoSam and Sherpa to obtain the results in a fully automated way. For a typical set of fiducial cuts the electroweak corrections lead to a modification of the total cross section of up to 3 per cent, depending on the jet multiplicity. We find substantial contributions in differential distributions, leading to tens of per cent corrections for phase space regions within the reach of the LHC. Furthermore we investigate the importance of pho…
If studies of electroweak gauge boson final states at the Large Hadron Collider, for Standard Model physics and beyond, are sensitive to effects of the initial state's transverse momentum distribution, appropriate generalizations of QCD shower evolution are required. We propose a method to do this based on QCD transverse momentum dependent (TMD) factorization at high energy. The method incorporates experimental information from the high-precision deep inelastic scattering (DIS) measurements, and includes experimental and theoretical uncertainties on TMD parton density functions. We illustrate …
We discuss the possible signatures in the electroweak symmetry breaking sector by new strong dynamics at future hadron colliders such as the Tevatron upgrade, the LHC and VLHC, and $e^+e^-$ linear colliders. Examples include a heavy Higgs-like scalar resonance, a heavy Technicolor-like vector resonance and pseudo-Goldstone states, non-resonance signatures via enhanced gauge-boson scattering and fermion compositeness.
Top-quark physics plays an important role at hadron colliders such as the Tevatron collider at Fermilab or the upcoming Large Hadron Collider (LHC) at CERN. Given the planned experimental precision, detailed theoretical predictions are mandatory. In this article we present analytic results for the complete electroweak corrections to gluon induced top-quark pair production, completing our earlier results for the quark-induced reaction. As an application we discuss top-quark pair production at Tevatron and at LHC. In particular we show that, although small for inclusive quantities, weak correcti…
Multi-boson splashes at future colliders from electroweak compositeness
Sorbonne Université & CNRS（索邦大学与法国国家科学研究中心）；Southern Denmark Univ.（南丹麦大学）；Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I（里昂第一大学、法国国家科学研究中心/法国国家粒子物理研究所、IP2I）；University of Johannesburg（约翰内斯堡大学）；Indian Institute of Technology Delhi（德里印度理工学院）；University of Graz（格拉茨大学）
Since the W and Z discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard …
In the Standard Model the process $q\bar{q}\rightarrow q\bar{q}V$ (where $V=W^\pm,Z^0$ or $γ$) can occur via gluon exchange and also via $W^\pm$ or $Z^0$ exchange. The corresponding chromodynamic and electroweak amplitudes can interfere with one another. These interference cross sections are largest when the exchanged $W^\pm$ or $Z^0$ is on-shell when they are also odd under parity. Interference cross sections computed using helicity-amplitude techniques are presented for all interesting subprocesses as well as for the processes $q\bar{q}\rightarrow q\bar{q} l\bar{l}$ in which the lepton pair …
We present here the summary of the "Electroweak and Searches in DIS and Hadron Colliders" working group activities at the DIS 2010 conference. The theory contributions will be presented first, followed by the experimental ones. The experimental results include measurements from the Tevatron (CDF and \DO) and HERA (H1 and ZEUS) experiments, and studies from the LHC (ATLAS and CMS). Results from the B-factories (BaBar and Belle) and from NA62 are also summarised.
We study phenomenological consequences of the strong first-order electroweak phase transition in an extension of the standard model with an inert doublet and vector-like leptons motivated by the muon $g-2$ anomaly and dark matter. We find that a condition for the strong first-order electroweak phase transition inevitably induces a large logarithmic enhancement in $Z$ boson decays, which relegates the explanation of the anomalous muon $g-2$ at below 2$σ$ level. Our analysis shows that future lepton collider experiments, especially the Giga-$Z$ at the International Linear Collider and Tera-$Z$ a…
We discuss the prospects for detecting at a muon collider the massive new vector resonances V and light pseudo-Nambu-Goldstone bosons P of a typical strongly interacting electroweak sector (as represented by the BESS model). Expected sensitivities to V's at a high energy collider are evaluated and the excellent prospects for discovering P's via scanning at a low energy collider are delineated.
We present the full O(alpha) electroweak radiative corrections to 9 Higgs boson production with the beam polarization at the International Linear Collider(ILC). The computation is performed with the help of GRACE-Loop. We compared the full O(alpha) electroweak radiative corrections with the factorized initial state radiation(ISR) effects to estimate the pure weak corrections. This reveals the pure weak corrections are not negligible and should be taken into account for the precision measurements of the Higgs boson property at the ILC experiments.
We calculate the electroweak corrections to the production of WWZ and ZZZ at the linear collider in the Standard Model. These processes are important for the extraction of the quartic couplings of the massive gauge bosons which can be a window on the mechanism of spontaneous symmetry breaking. We find that the weak corrections to some kinematic distributions show new features and hence cannot be explained by an overall scale factor.
Next-to-leading order electroweak and QCD radiative corrections to the Drell-Yan process with high dimuon masses for experiments CMS LHC at CERN have been studied in fully differential form. The FORTRAN code READY for numerical analysis of Drell-Yan observables has been presented. The radiative corrections are found to become significant for CMS LHC experiment setup.
We calculate the full $\mathcal{O}(α_s^2α)$ corrections to the process of gluino pair production at hadron colliders in the framework of the real MSSM. We show that these contributions can be neglected at the LHC performing a scan over a wide region of the parameter space. The impact of these corrections in the parameter range investigated at the Tevatron is small.
We discuss possibilities to measure the tt-gamma and ttZ couplings at hadron and lepton colliders. We also briefly describe how these measurements can be used to constrain the parameter space of models of new physics, in particular Little Higgs models.
We review our recent global analysis for probing the electroweak symmetry breaking (EWSB) mechanism by the universal effective Lagrangian description. After summarizing and commenting upon the current bounds for the EWSB parameters, we focus on testing them at the forthcoming high energy colliders such as the CERN LHC and the future linear colliders. We develop a precise electroweak power counting method (a la Weinberg) and formulate the longitudinal-Goldstone boson equivalence as a necessary criterion for sensitively probing the EWSB sector. Armed with these, we systematically estimate and cl…
Some possible tests of physics beyond the Standard Model in the next generation collider experiments are considered. The main emphasis is put on the processes which may be studied in the non-conventional $e^-e^-$, $e^-γ$ and $γγ$ operation modes of the next linear collider (NLC). In particular, sensitivity of the NLC for testing the gauge boson self-interactions through the reaction $e^-γ\to W^-ν$ is investigated. High energy tests of the susy and non-susy left-right symmetric models are analysed.
We classify the sensitivities of the future high energy hadron and electron colliders, such as the LHC and the future Linear Colliders, to probing all the next-to-leading order (NLO) bosonic operators for studying the electroweak symmetry breaking (EWSB) mechanism. We first develop a power counting rule (a generalization of Weinberg's counting method for the nonlinear sigma model) for the electroweak theories formulated by the chiral Lagrangian. Then, we formulate the Longitudinal-Goldstone Boson Equivalence Theorem as a physical criterion to discriminate the scattering processes that are not …
An effective lagrangian describing a strong interacting electroweak sector is considered. It contains new vector and axial-vector resonances all degenerate in mass and mixed with $W$ and $Z$. The model, for large mass of these degenerate gauge bosons, becomes identical to the standard model in the classical limit of infinite Higgs mass. The limits on the parameter space of this model from future $e^+e^-$ colliders are presented.
We present standard model predictions for a four fermion reaction e+ e- -> mu+ mu- bar_b b being one of the best detection channels of a low mass Higgs boson produced through the Higgsstrahlung mechanism at a linear collider. We include leading virtual and real QED corrections to all the lowest order Feynman diagrams of e+ e- -> mu+ mu- bar_b b and the complete O(alpha) electroweak corrections to the Z-Higgs production and to the Z and Higgs boson decay widths in the double pole approximation.
The measurement of Standard Model processes tests the validity of the model at a given scale and is simultaneously sensitive to new physics through loop effects or interference with the Standard Model amplitudes. A variety of studies has been done to see what a linear collider in the energy range MZ < sqrt{s} < 1 TeV can offer. The work that has been done within the ECFA/DESY workshop on linear colliders is reviewed, especially what was not included in the TESLA TDR.
We summarize the status of calculations of the electroweak radiative corrections to W and Z boson production via the Drell-Yan mechanism at hadron colliders. To fully exploit the precision physics potential of the high-luminosity environment of the Fermilab Tevatron pbar p (Run II) and the CERN LHC pp colliders, it is crucial that the theoretical predictions are well under control. The envisioned precision physics program includes a precise measurement of the W boson mass and width, and the (leptonic) weak mixing angle, as well as probing the Standard Model (SM) of electroweak interactions at …
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 …
If there are no light Higgs bosons found below $\cal O$(800 GeV) or so, the interactions among longitudinally-polarized vector bosons ($\wl$) will become strong at the TeV region, and new physics that is responsible for the electroweak symmetry breaking must emerge at this energy scale. We discuss the phenomenological prospects of the Strongly-interacting Electro-Weak Sector (SEWS) at future TeV linear colliders and hadronic supercolliders.
We calculate the subjet rates for jets produced in hadron collisions. The kt algorithm is used to define the jets and allows the theoretical calculation to sum both the leading and next-to-leading logarithms in the resolution variable, ycut. We also ensure that our calculation matches exactly the leading order in alpha_s result and has sensible behaviour near thresholds.
We study the complementarity of the proposed multi-TeV muon colliders and the near-future gravitational wave (GW) detectors to the first order electroweak phase transition (FOEWPT), taking the real scalar extended Standard Model as the representative model. A detailed collider simulation shows the FOEWPT parameter space can be greatly probed via the the vector boson fusion production of the singlet, and its subsequent decay to the di-Higgs or di-boson channels. Especially, almost all the parameter space yielding detectable GW signals can be probed by the muon colliders. Therefore, if we could …
We study photoproduction of jets and heavy flavors in a polarized collider mode of HERA and in polarized $ep$ collisions at $\sqrt{S}\approx 30$ GeV. We examine the sensitivity of the cross sections and their asymmetries to the proton's polarized gluon distribution and to the completely unknown parton distributions of longitudinally polarized photons.
We show that high energy measurements of Drell-Yan at the LHC can serve as electroweak precision tests. Dimension-6 operators, from the Standard Model Effective Field Theory, modify the high energy behavior of electroweak gauge boson propagators. Existing measurements of the dilepton invariant mass spectrum, from neutral current Drell-Yan at 8 TeV, have comparable sensitivity to LEP. We propose measuring the transverse mass spectrum of charged current Drell-Yan, which can surpass LEP already with 8 TeV data. The 13 TeV LHC will elevate electroweak tests to a new precision frontier.
We describe the impact of the full one-loop Electro-Weak terms of O($α_sα^3_{EM}$) entering the electron-positron into three-jet cross-section. We include both factorisable and non-factorisable virtual corrections, photon bremsstrahlung but not the real emission of $W^\pm$ and $Z$ bosons. We show preliminary results and we discuss the impact of the Electro-Weak corrections on three-jet observables.
High-energy data has been accumulating over the last ten years, and it should not be ignored when making decisions about the future experimental program. In particular, we argue that the electroweak data collected at LEP, SLC and Tevatron indicate a light scalar particle with mass less than 500 GeV. This result is based on considering a wide variety of theories including the Standard Model, supersymmetry, large extra dimensions, and composite models. We argue that a high luminosity, 600 GeV e+e- collider would then be the natural choice to feel confident about finding and studying states conne…
I review the physics capabilities of the machines proposed for the next generation of high-energy experimentation: in hadron physics, the LHC, and in electron physics, a $500$--$1500$ GeV $e^+e^-$ linear collider. Using for illustration two specific models of electroweak symmetry breaking, I show how the $pp$ and $e^+e^-$ techniques are expected to complement one another in the exploration of the next scale of physics. [invited lecture at the 22nd INS Symposium, Tokyo] (text only; complete paper with figures and tables available by anonymous ftp from preprint.slac.stanford.edu, in the director…
A complete parton level analysis of lv + four jets production at the LHC is presented, including all processes at order O(alpha^6), O(alpha^4*alpha_s^2) and O(alpha^2*alpha_s^4). The infinite Higgs mass scenario, which is considered as a benchmark for strong scattering theories and is the limiting case for composite Higgs models, is confronted with the Standard Model light Higgs predictions in order to determine whether a composite Higgs signal can be detected as an excess of events in boson--boson scattering.
At present and future hadron colliders, the precision physics program started in the past will be continued. In particular, a precise determination of the W boson mass will be carried out. This requires the calculation of the radiative corrections and their implementation in Monte Carlo event generators for data analysis. In this talk, the status of the calculation of the order alpha electroweak radiative corrections is reviewed and a study of the impact of higher order QED corrections on the W boson mass is presented.
We study the electroweak phase transition in three scalar extension models beyond the Standard Model. Assuming new scalars are decoupled at some heavy scale, we use the covariant derivative expansion method to derive all of the dimension-6 effective operators, whose coefficients are highly correlated in a specific model. We provide bounds to the complete set of dimension-6 operators by including the electroweak precision test and recent Higgs measurements. We find that the parameter space of strong first-order phase transitions (induced by the $|H|^6$ operator) can be probed extensively in $Zh…
For the envisioned high precision measurement of the W boson mass at the Tevatron and LHC it is crucial that the theoretical predictions for the W and Z production processes are under control. We briefly summarize the status of the electroweak radiative corrections to p p(pbar) -> W -> l nu and p p(pbar) -> Z,gamma -> l+ l- (l=e,mu), and present some numerical results.
