{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.155627.v2","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2860928"}},{"@id":"https://doi.org/10.1038/s41586-026-10168-5","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"CMS Collaboration"},"creator":{"@type":"Organization","name":"CMS Collaboration"},"datePublished":"2026","description":"In the standard model of particle physics, the masses of the W and Z bosons, the carriers of the weak interaction, are uniquely related. A precise determination of their masses is important because quantum loops of heavy, undiscovered particles could modify this relationship. Although the Z mass is known to the remarkable precision of 22 parts per million (2.0 MeV), the W mass is known much less precisely. A global fit to measured electroweak observables predicts the W mass with 6 MeV uncertainty [1$-$3]. Reaching a comparable experimental precision would be a sensitive and fundamental test of the standard model, made even more urgent by a recent challenge to the global fit prediction by a measurement from the CDF Collaboration at the Fermilab Tevatron collider [4]. Here we report the measurement of the W mass by the CMS Collaboration at the CERN LHC, based on a large data sample of $W \\to \\mu \\nu$ events collected in 2016 at the proton-proton collision energy of 13 TeV. The measurement exploits a high-granularity maximum likelihood fit to the kinematic properties of muons produced in W decays. By combining an accurate determination of experimental effects with marked in situ constraints of theoretical inputs, we reach a precise measurement of the W mass, of 80 360.2 $\\pm$ 9.9 MeV, in agreement with the standard model prediction.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t1","@type":"Dataset","description":"Comparison of the nominal $\\mathit{m}_{Z}$ measurement and its uncertainty (total or only from $\\mathit{p}_{T}^{Z}$ modeling), with the alternative measurements using...","name":"mass_summary_Zwlike_ptZ_modeling"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t2","@type":"Dataset","description":"Comparison of the nominal $\\mathit{m}_{W}$ measurement and its uncertainty (total or only from $\\mathit{p}_{T}^{W}$ modeling), with the alternative measurements using...","name":"mass_summary_W_ptW_modeling"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t3","@type":"Dataset","description":"Comparison of the nominal $\\mathit{m}_{W}$ measurement and its uncertainty (total or only from the CT18Z PDF set), with the alternative...","name":"mass_summary_W_pdfUnscaled"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t4","@type":"Dataset","description":"Comparison of the nominal $\\mathit{m}_{W}$ measurement and its uncertainty (total or only from the CT18Z PDF set), with the alternative...","name":"mass_summary_W_pdfScaled"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t5","@type":"Dataset","description":"$d\\sigma^{W}/d\\mathit{p}_{T}\\ (pb\\,/\\,GeV)$: Generator-level $\\mathit{p}_{T}^{W}$ distribution and uncertainty. The last column reports the result of a simultaneous fit to the single...","name":"diffXsec_W_pt"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t6","@type":"Dataset","description":"$d\\sigma^{Z}/d|\\mathit{y}|\\ (pb)$: Unfolded measured $\\mathit{y}^{Z}$ distribution compared with the generator-level predictions before the likelihood fit or after the W-like $\\mathit{m}_{Z}$...","name":"diffXsec_Zwlike_y"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t7","@type":"Dataset","description":"$d\\sigma^{Z}/d\\mathit{p}_{T}\\ (pb\\,/\\,GeV)$: Unfolded measured $\\mathit{p}_{T}^{Z}$ distribution compared with the generator-level predictions before the likelihood fit or after the W-like $\\mathit{m}_{Z}$...","name":"diffXsec_Zwlike_pt"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t8","@type":"Dataset","description":"$d\\sigma^{W}/d\\mathit{p}_{T}\\ (pb\\,/\\,GeV)$: Generator-level $\\mathit{p}_{T}^{W}$ distribution and uncertainty, before and after running the helicity fit. The measured cross section in each...","name":"diffXsec_W_pt_helFit"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t9","@type":"Dataset","description":"$d\\sigma^{W}/d|\\mathit{y}|\\ (pb)$: Generator-level $\\mathit{y}^{Z}$ distribution and uncertainty, before and after running the helicity fit. The measured cross section in each...","name":"diffXsec_W_y_helFit"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t10","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (both nominal and 'global') for all nuisance parameters in the W boson mass fit, sorted...","name":"Postfit_pulls_constraints_impacts_W"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t11","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (both nominal and 'global') for all nuisance parameters in the W boson mass fit (charge...","name":"Postfit_pulls_constraints_impacts_W_massDiffCharge"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t12","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (both nominal and 'global') for all nuisance parameters in the W-like Z boson mass fit,...","name":"Postfit_pulls_constraints_impacts_Zwlike"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t13","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (both nominal and 'global') for all nuisance parameters in the W-like Z boson mass fit...","name":"Postfit_pulls_constraints_impacts_Zwlike_flipEventSplit"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t14","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (both nominal and 'global') for all nuisance parameters in the W-like Z boson mass fit...","name":"Postfit_pulls_constraints_impacts_Zwlike_massDiffCharge"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t15","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (only nominal) for all nuisance parameters in the Z boson mass fit (using dimuon mass),...","name":"Postfit_pulls_constraints_impacts_Zdilepton"},{"@id":"https://doi.org/10.17182/hepdata.155627.v2/t16","@type":"Dataset","description":"Postfit pulls, constraints, and impacts (only nominal) for all nuisance parameters in the W boson mass fit (helicity cross section...","name":"Postfit_pulls_constraints_impacts_W_helFit"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2860928?version=2"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/155627"}],"inLanguage":"en","name":"High-precision measurement of the W boson mass with the CMS experiment at the LHC","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2860928?version=2","version":2}