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Mark Lancaster University of Manchester / UCL

Future Electroweak Precision Measurements. Mark Lancaster University of Manchester / UCL. Motivation: Fertile Ground. TREE LEVEL SM. Rad. Corr. LOOP LEVEL SM. ~ 500 MeV. Requires 0.5% precision to probe. TREE LEVEL Mw. Mw measurements now probing at O(10 MeV).

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Mark Lancaster University of Manchester / UCL

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  1. Future Electroweak Precision Measurements Mark Lancaster University of Manchester / UCL

  2. Motivation: Fertile Ground TREE LEVEL SM Rad. Corr LOOP LEVEL SM ~ 500 MeV. Requires 0.5% precision to probe TREE LEVEL Mw Mark Lancaster | Electroweak Precision Measurements

  3. Mw measurements now probing at O(10 MeV) Mark Lancaster | Electroweak Precision Measurements

  4. Harbinger of new interactions B oscillations and loop corrections to Z mass Mark Lancaster | Electroweak Precision Measurements

  5. Higgs Mass from fits to EWK data Tevatron mT LEP mW Tevatron mW Significant improvements in mW at Tevatron Mark Lancaster | Electroweak Precision Measurements

  6. Just prior to Higgs Discovery… Mark Lancaster | Electroweak Precision Measurements

  7. In the Higgs Era Motivation Remains… Limits placed on Higgs couplings and TGCs are also determined by how well the EWKPO are known Dark : perfect EWKPO Light : measured EWKPO Jorge De Blas : arXiv:1803.00939, 1611.05354, 1905.03764 Mark Lancaster | Electroweak Precision Measurements

  8. Higgs Self Coupling from Precision EWK arXiv:1702.07678 Mark Lancaster | Electroweak Precision Measurements

  9. Higgs Self Coupling from precision EWK arXiv:1702.10737 Mark Lancaster | Electroweak Precision Measurements

  10. Programme of measurements All future ee-colliders have dedicated running periods precision EWK measurements: mW, mZ, mTOPin addition to direct Higgs/BSM running Mark Lancaster | Electroweak Precision Measurements

  11. Theory Uncertainties At LEP theory uncertainty was 20% of the experimental uncertainty but with x 4-20 improvement in experimental precision requires Z-pole and WW calculations with one or more additional orders in the calculation in both QCD & EWK  NNNLO See Stefan’s talk Mark Lancaster | Electroweak Precision Measurements

  12. And also precise values of 𝜶EM & 𝜶S So need ⧍MW < 5 MeV measurement for this to be potentially sensitive to BSM Z-data can significantly reduce 𝛼S and 𝛼EM uncertainties e.g. by xO(5) at FCC. Mark Lancaster | Electroweak Precision Measurements

  13. 𝜶S and 𝜶EM Improvement AFB(𝜇𝜇) above and below Z-pole arXiv:1703.01626 See David d'Enterria’s talk in QCD session Mark Lancaster | Electroweak Precision Measurements

  14. Impact of BSM Effects O (10) MeV SM with LHC mH Mark Lancaster | Electroweak Precision Measurements

  15. New colliders at MZ and 2MW (and 2MTOP) Z W (WW) Mark Lancaster | Electroweak Precision Measurements

  16. Precision EWK Observables Submission Inputs: 29, 145, 101, 132, 135 LHeC can measure sin2𝜃W as f(E). LHeC : Mw to 10 MeV but can measure PDFs allowing HL-LHC to half PDF uncertainty and achieve O(5 MeV) Mw. ILC/CLIC : Mw to 5 MeV similar to HL-LHC/TeV average. Mark Lancaster | Electroweak Precision Measurements

  17. Systematics • beam energy and energy spread determination • ISR • luminosity • Beam energy dominates: use LEP resonance depolarizing • method (0.1 MeV). • At FCC and CEPC will use non-colliding (pilot) bunches concurrently • to avoid need to extrapolate between measuring periods with • expected uncertainty 0.1 – 0.4 MeV. Mark Lancaster | Electroweak Precision Measurements

  18. Top Mass Threshold scans give well-defined mTOP Current uncertainty ~ 400 MeV from Tevatron/LHC CLIC/FCC/ILC all expected to achieve: 15-20 MeV statistical 10-20 MeV systematic But presently uncertainty from theory is larger: 30 MeV (𝛼S), 40 MeV (HO). This will be reduced by the measurements at Z-pole. O (25) MeV Mark Lancaster | Electroweak Precision Measurements

  19. Characterise Improvements via Oblique Parameters S & T determined much better for experiments at Mz (FCC, CEPC) but W & Y much better at CLIC that has highest energy range 0.1 has sensitivity to Higgs TGC x20 SM Mark Lancaster | Electroweak Precision Measurements

  20. The power of polarisation (ILC/CLIC) CLIC: unpolarised CLIC: polarised Mark Lancaster | Electroweak Precision Measurements

  21. Sterile neutrinos at Z-pole Mark Lancaster | Electroweak Precision Measurements

  22. sin2𝜽W @ DUNE Submission:31 DUNE DUNE: 0.35% precision could clarify the NuTeV 3𝜎 discrepancy wrt. SM. Mark Lancaster | Electroweak Precision Measurements

  23. Submission:118 𝜶EM @ MuonE a𝜇HVP(SM) = (693 ± 2.5) x 10-10 : frome+e- hadrons annihilation data Exp discrepancy wrt. to SM : 27 x 10-10 Aim to directly measure a𝜇HVP(SM) in t-channel e𝜇 scattering to same precision as e+e- data. Measure differential 𝜎 as function of t : running of 𝛼EM(t) Also needs 0.01% theory & so NNLO QED calculations e+ e- e- e- 𝜇 𝜇 Mark Lancaster | Electroweak Precision Measurements

  24. Summary Colliders at Mw, 2Mw and 2MTOP will improve precision of EWK precision observables by factors of 5-20. 2 orders of magnitude improvement in S & T (FCC) and first significant probes of W & Y (CLIC). This enters the regime where rad. corrections from BSM can be probed accurately and tests the SM at beyond 2-loop. EWK observables can also be used together with direct Higgs measurements to improve Higgs self-coupling determinations To benefit from this improved experimental precision requires commensurate improvements in theory. Mark Lancaster | Electroweak Precision Measurements

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