Search

The Future Circular Collider (FCC) at CERN, a proposed100km circular facility with several collidersin succession, culminates in a100TeV proton–proton collider. It offers a vast new domain of explorationin particle physics, with orders-of-magnitude advances in terms of precision, sensitivity, and energy.The implementation plan published in 2018 foresees, as a first step, an electroweak factory electron–positron collider. This high-luminosity facility, operating at centre-of-mass energies between 90 and365GeV, will study the heavy particles of the Standard Model (SM), Z, W, and Higgs bosons, andtop quarks with unprecedented accuracy. The physics programme offers great discovery potential:(i) through precision measurements, (ii) through sensitive searches for symmetry violations, forbidden,or extremely rare decays, and (iii) through the search for direct observation of new particles withextremely small couplings. The electroweak factorye+e−collider constitutes a real challenge to thetheory and to precision calculations, triggering the need for the development of new mathematicalmethods and software tools. A first workshop in 2018 focused on the first FCC-ee stage, the Tera-Z, andconfronted the theoretical status of precision Standard Model calculations on the Z boson resonanceto the experimental demands.The second workshop, in January 2019, extended the scope to the next stages, with the pro-duction of W bosons (FCC-ee-W), the Higgs boson (FCC-ee-H), and top quarks (FCC-ee-tt). In par-ticular, the theoretical precision in the determination of the crucial input parameters,αQED,αQCD,MW, andmt, at the level of FCC-ee requirements was thoroughly discussed. The requirements onStandard Model theory calculations were spelt out, so as to meet the demanding accuracy of theFCC-ee experimental potential. The discussion of innovative methods and tools for multiloop calcu-lations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were dis-cussed, including effective theory approaches. The reports of 2018 and 2019 serve as white papers ofthe workshop results and subsequent developments. The FCC at CERN, a proposed 100-km circular facility with several colliders in succession, culminates with a 100 TeV proton-proton collider. It offers a vast new domain of exploration in particle physics, with orders of magnitude advances in terms of Precision, Sensitivity and Energy. The implementation plan foresees, as a first step, an Electroweak Factory electron-positron collider. This high luminosity facility, operating between 90 and 365 GeV centre-of-mass energy, will study the heavy particles of the Standard Model, Z, W, Higgs, and top with unprecedented accuracy. The Electroweak Factory $e^+e^-$ collider constitutes a real challenge to the theory and to precision calculations, triggering the need for the development of new mathematical methods and software tools. A first workshop in 2018 had focused on the first FCC-ee stage, the Tera-Z, and confronted the theoretical status of precision Standard Model calculations on the Z-boson resonance to the experimental demands. The second workshop in January 2019, which is reported here, extended the scope to the next stages, with the production of W-bosons (FCC-ee-W), the Higgs boson (FCC-ee-H) and top quarks (FCC-ee-tt). In particular, the theoretical precision in the determination of the crucial input parameters, alpha_QED, alpha_QCD, M_W, m_t at the level of FCC-ee requirements is thoroughly discussed. The requirements on Standard Model theory calculations were spelled out, so as to meet the demanding accuracy of the FCC-ee experimental potential. The discussion of innovative methods and tools for multi-loop calculations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were discussed, in particular the effective theory approaches. The reports of 2018 and 2019 serve as white papers of the workshop results and subsequent developments.

The precise measurement of the mass of the W boson plays an essential role for precision tests of the Standard Model (SM) and indirect searches for new physics through global fits to electroweak observables. Cross-section measurements near the W pair production threshold at a possible future e−e+ collider promise to reduce the experimental uncertainty to the level of 3 MeV at an International Linear Collider (ILC), while a high-luminosity circular collider offers a potential improvement to 0.5 MeV in the case of the FCC-ee or 1 MeV at the CEPC., CERN Yellow Reports: Monographs, Vol. 3 (2020): Theory for the FCC-ee: Report on the 11th FCC-ee Workshop, Theory and Experiments, CERN, Geneva, 8–11 January 2019

This report was prepared in the context of the LPCC "Electroweak Precision Measurements at the LHC WG" and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell-Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. Fil: Alioli, S.. Organización Europea para la Investigación Nuclear; Suiza Fil: Arbuzov, S. B. Instituto Central de Investigaciones Nucleares; Rusia Fil: Bardin, D. Yu. Instituto Central de Investigaciones Nucleares; Rusia Fil: Barze, L.. Universita Degli Studi Di Pavia; Italia Fil: Bernaciak, C.. University at Buffalo; Estados Unidos. State University of New York; Estados Unidos Fil: Bondarenko, S. G.. Instituto Central de Investigaciones Nucleares; Rusia Fil: Carloni Calame, C.. State University of New York; Estados Unidos. University at Buffalo; Estados Unidos Fil: Chiesa, M.. State University of New York; Estados Unidos. University at Buffalo; Estados Unidos Fil: Dittmaier, S.. Albert Ludwigs University of Freiburg; Alemania Fil: Ferrera, G.. Università degli Studi di Milano; Italia Fil: de Florian, Daniel Enrique. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Grazzini, M.. Universitat Zurich; Suiza Fil: Hoche, S.. National Accelerator Laboratory; Estados Unidos Fil: Huss, A.. Institute for Theoretical Physics; Suiza Fil: Jadach, S.. Institute of Nuclear Physics; Polonia Fil: Kalinovskaya, L. V.. Instituto Central de Investigaciones Nucleares; Rusia Fil: Karlberg, A.. University of Oxford; Reino Unido Fil: Krauss, F.. University of Durham; Reino Unido Fil: Li, Y.. Fermi National Accelerator Laboratory; Estados Unidos Fil: Martinez, H.. Universita Degli Studi Di Pavia; Italia Fil: Montagna, G.. Universita Degli Studi Di Pavia; Italia Fil: Muck, A.. Universidad Técnica de Aquisgrán; Alemania Fil: Nason, P.. No especifíca; Fil: Nicrosini, O.. No especifíca; Fil: Petriello, F.. Argonne National Laboratory; Estados Unidos. Northwestern University; Estados Unidos Fil: Piccinini, F.. No especifíca; Fil: Placzek, W.. Jagiellonian University; Polonia Fil: Prestel, S.. National Accelerator Laboratory; Estados Unidos Fil: Re, E.. Universite Savoie Mont Blanc; Francia Fil: Sapronov, A. A.. Instituto Central de Investigaciones Nucleares; Rusia Fil: Schonherr, M.. Universitat Zurich; Suiza Fil: Schwinn, C.. Universidad Técnica de Aquisgrán; Alemania Fil: Vicini, A.. Università degli Studi di Milano; Italia Fil: Wackeroth, D.. University of California; Estados Unidos. University at Buffalo; Estados Unidos Fil: Was, Z.. Polish Academy of Sciences; Polonia Fil: Zanderighi, G.. Organización Europea para la Investigación Nuclear; Suiza. University of Oxford; Reino Unido

This report was prepared in the context of the LPCC Electroweak Precision Measurements at the LHC WG ( https://lpcc.web.cern.ch/lpcc/index.php?page=electroweak_wg ) and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell–Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. All the codes considered in this report have been run by the respective authors, and the results presented here constitute a benchmark that should be always checked/reproduced before any high-precision analysis is conducted based on these codes. In order to simplify these benchmarking procedures, the codes used in this report, together with the relevant input files and running instructions, can be found in a repository at https://twiki.cern.ch/twiki/bin/view/Main/DrellYanComparison .

This report was prepared in the context of the LPCC Electroweak Precision Measurements at the LHC WG (https://lpcc.web.cern.ch/lpcc/index.php?page=electroweak_wg) and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell–Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. All the codes considered in this report have been run by the respective authors, and the results presented here constitute a benchmark that should be always checked/reproduced before any high-precision analysis is conducted based on these codes. In order to simplify these benchmarking procedures, the codes used in this report, together with the relevant input files and running instructions, can be found in a repository at https://twiki.cern.ch/twiki/bin/view/Main/DrellYanComparison., The European Physical Journal C, 77 (5), ISSN:1434-6044, ISSN:1434-6052

This report was prepared in the context of the LPCC Electroweak Precision Measurements at the LHC WG ( https://lpcc.web.cern.ch/lpcc/index.php?page=electroweak_wg ) and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell–Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. All the codes considered in this report have been run by the respective authors, and the results presented here constitute a benchmark that should be always checked/reproduced before any high-precision analysis is conducted based on these codes. In order to simplify these benchmarking procedures, the codes used in this report, together with the relevant input files and running instructions, can be found in a repository at https://twiki.cern.ch/twiki/bin/view/Main/DrellYanComparison . This report was prepared in the context of the LPCC "Electroweak Precision Measurements at the LHC WG" and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell-Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the $W$ boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe.

This report was prepared in the context of the LPCC Electroweak Precision Measurements at the LHC WG (https://lpcc.web.cern.ch/lpcc/index.php?page=electroweak_wg) and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell–Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. All the codes considered in this report have been run by the respective authors, and the results presented here constitute a benchmark that should be always checked/reproduced before any high-precision analysis is conducted based on these codes. In order to simplify these benchmarking procedures, the codes used in this report, together with the relevant input files and running instructions, can be found in a repository at https://twiki.cern.ch/twiki/bin/view/Main/DrellYanComparison.

We present predictions of the total cross sections for pair production of squarks and gluinos at the LHC, including the stop-antistop production process. Our calculation supplements full fixed-order NLO predictions with resummation of threshold logarithms and Coulomb singularities at next-to-leading logarithmic (NLL) accuracy, including bound-state effects. The numerical effect of higher-order Coulomb terms can be as big or larger than that of soft-gluon corrections. For a selection of benchmark points accessible with data from the 2010-2012 LHC runs, resummation leads to an enhancement of the total inclusive squark and gluino production cross section in the 15-30 % range. For individual production processes of gluinos, the corrections can be much larger. The theoretical uncertainty in the prediction of the hard-scattering cross sections is typically reduced to the 10 % level., Comment: 45 pages, 16 Figures, LaTex. v2: published version. Grids with numerical results for the NLL cross sections for squark and gluino production at the 7/8 TeV LHC are included in the submission and are also available at http://omnibus.uni-freiburg.de/~cs1010/susy.html

We compute the total top-quark pair production cross section at the Tevatron and LHC based on approximate NNLO results, and on the summation of threshold logarithms and Coulomb enhancements to all orders with next-to-next-to-leading logarithmic (NNLL) accuracy, including bound-state effects. We find \sigma_{t\bar t} = 7.22^{+0.31+0.71}_{-0.47-0.55} pb at Tevatron and \sigma_{t\bar t} = 162.6^{+7.4+15.4}_{-7.6-14.7} pb at LHC with 7 TeV c.o.m. energy, for m_t=173.3 GeV. The implementation of joint soft and Coulomb resummation, its ambiguities, and the present theoretical uncertainty are discussed in detail. We further obtain new approximate results at N3LO., Comment: 55 pages, LaTeX, 13 figures