Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV (1412.8662v2)

Abstract: Properties of the Higgs boson with mass near 125 GeV are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include gamma gamma, ZZ, WW, tau tau, bb, and mu mu pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and up to 19.7 inverse femtobarns at 8 TeV. From the high-resolution gamma gamma and ZZ channels, the mass of the Higgs boson is determined to be 125.02 +0.26 -0.27 (stat) +0.14 -0.15 (syst) GeV. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is 1.00 +/- 0.09 (stat) +0.08 -0.07 (theo) +/- 0.07 (syst) at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found.

• The paper presents a precise measurement of the Higgs boson mass at 125.02 GeV with small statistical and systematic uncertainties.
• It details comprehensive decay channel analyses (gg, ZZ, WW, etc.) that confirm event yields closely match Standard Model predictions.
• The study constrains invisible decay modes and refines coupling tests, paving the way for future explorations beyond the Standard Model.

An In-Depth Analysis of Higgs Boson Properties and Standard Model Conformity

The paper presented by the CMS Collaboration at CERN meticulously investigates the properties of the Higgs boson with a mass proximate to 125 GeV, as observed through proton-proton collisions at the Large Hadron Collider (LHC). Utilizing the CMS experimental setup, the paper synthesizes extensive production and decay measurements retrieved during 2011 and 2012. The results predominantly encompass decay channels involving gg, ZZ, WW, tt, bb, and mm pairs.

Key Measurements and Outcomes

The research affirms a precise determination of the Higgs boson mass as 125.02 GeV with uncertainty margins of ▯0.27(stat)▯0.15(syst)GeV. These values were discerned from high-resolution examinations in the gg and ZZ channels. Notably, the paper confirms the consistency of event yields and decay channel analyses with the postulations of the Standard Model (SM), indicating a combined signal strength aligning closely with the theoretical SM forecast (1.00▯0.09(stat)▯0.07(theo)▯ 0.07(syst)).

Crucially, the paper probes the Higgs boson’s couplings for aberrations in magnitude against SM predictions through diversely tagged analyses and comprehensive searches for invisible and undetected decays. Across multifarious analyses, no significant discrepancies were observed from expected SM behavior.

Implications and Future Prospects

The executed analyses hold profound implications for particle physics. The nuance in measuring the Higgs boson mass with such precision helps consolidate the foundation upon which SM predictions rest. The corroboration of Higgs properties across vast datasets enhances our understanding of particle physics, potentially minimizing the parameter space where theories beyond the SM, such as supersymmetry, might still be viable.

Comprehensively exploring Higgs interactions through ggH, VBF, and ttH processes, the research provides a robust ground for future inquiry into loop-induced processes like gluon and photon interactions. Adding constraints on invisible Higgs decays through direct limits on the boson's natural width (observed to remain within 1.7 GeV) further extends these findings.

Conclusion

The research undertaken by CMS is a testament to the depth and precision that contemporary collider experiments can achieve. It reinforces the proficiency of the SM in describing Higgs interactions and is emblematic of the synergistic role of experimental validations in high-energy physics. Looking forward, these findings lay the groundwork for narrowing down potential new physics theories and fine-tuning experimental techniques to further explore the particle's elusive characteristics. As more data is cultivated, these studies can serve as a template for interrogating potential deviations from the SM at increased collision energies, promising further insight into the fundamental ethos of matter and forces.