Future Electroweak Precision Measurements Mark Lancaster University of

Future Electroweak Precision Measurements Mark Lancaster University of Manchester / UCL

Motivation: Fertile Ground TREE LEVEL SM TREE LEVEL Mw Rad. Corr LOOP LEVEL SM ~ 500 Me. V. Requires 0. 5% precision to probe 2 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Mw measurements now probing at O(10 Me. V) 3 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Harbinger of new interactions B oscillations and loop corrections to Z mass 4 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Higgs Mass from fits to EWK data Tevatron m. T LEP m. W Tevatron m. W 5 14/05/19 Significant improvements in m. W at Tevatron Mark Lancaster | Electroweak Precision Measurements

Just prior to Higgs Discovery… 6 14/05/19 Mark Lancaster | Electroweak Precision Measurements

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 : ar. Xiv: 1803. 00939, 1611. 05354, 1905. 03764 7 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Higgs Self Coupling from Precision EWK ar. Xiv: 1702. 07678 8 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Higgs Self Coupling from precision EWK ar. Xiv: 1702. 10737 9 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Programme of measurements All future ee-colliders have dedicated running periods precision EWK measurements: m. W , m. Z , m. TOP in addition to direct Higgs/BSM running 10 14/05/19 Mark Lancaster | Electroweak Precision Measurements

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 11 14/05/19 Mark Lancaster | Electroweak Precision Measurements

And also precise values of �� EM & �� S So need �MW < 5 Me. V measurement for this to be potentially sensitive to BSM Z-data can significantly reduce �� S and �� EM uncertainties e. g. by x. O(5) at FCC. 12 14/05/19 Mark Lancaster | Electroweak Precision Measurements

�� S and �� EM Improvement AFB(���� ) above and below Z-pole ar. Xiv: 1703. 01626 See David d'Enterria’s talk in QCD session 13 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Impact of BSM Effects O (10) Me. V C m. H h LH t i w SM 14 14/05/19 Mark Lancaster | Electroweak Precision Measurements

New colliders at MZ and 2 MW (and 2 MTOP) Z W (WW) 15 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Precision EWK Observables Submission Inputs: 29, 145, 101, 132, 135 LHe. C can measure sin 2�� W as f(E). LHe. C : Mw to 10 Me. V but can measure PDFs allowing HL-LHC to half PDF uncertainty and achieve O(5 Me. V) Mw. ILC/CLIC : Mw to 5 Me. V similar to HL-LHC/Te. V average. 16 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Systematics - beam energy and energy spread determination - ISR - luminosity Beam energy dominates: use LEP resonance depolarizing method (0. 1 Me. V). 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 Me. V. 17 14/05/19 Mark Lancaster | Electroweak Precision Measurements

Top Mass Threshold scans give well-defined m. TOP Current uncertainty ~ 400 Me. V from Tevatron/LHC CLIC/FCC/ILC all expected to achieve: 15 -20 Me. V statistical O (25) Me. V 10 -20 Me. V systematic But presently uncertainty from theory is larger: 30 Me. V (�� S), 40 Me. V (HO). This will be reduced by the measurements at Z-pole. 18 14/05/19 Mark Lancaster | Electroweak Precision Measurements

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 x 20 SM 19 14/05/19 Mark Lancaster | Electroweak Precision Measurements

The power of polarisation (ILC/CLIC) CLIC: polarised 20 14/05/19 Mark Lancaster | Electroweak Precision Measurements CLIC: unpolarised

Sterile neutrinos at Z-pole 21 14/05/19 Mark Lancaster | Electroweak Precision Measurements

sin 2�� W @ DUNE Submission: 31 DUNE: 0. 35% precision could clarify the Nu. Te. V 3�� discrepancy wrt. SM. 22 14/05/19 Mark Lancaster | Electroweak Precision Measurements

�� EM @ Muon. E Submission: 118 HVP(SM) = (693 ± 2. 5) x 10 -10 : from e+e- hadrons annihilation data a�� Exp discrepancy wrt. to SM : 27 x 10 -10 e+ HVP(SM) in t-channel Aim to directly measure a�� e�� scattering to same precision as e+e- data. e. Measure differential �� as function of t : running of �� EM(t) Also needs 0. 01% theory & so NNLO QED calculations 23 14/05/19 Mark Lancaster | Electroweak Precision Measurements e- e- �� �

Summary Colliders at Mw, 2 Mw and 2 MTOP 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. 24 14/05/19 Mark Lancaster | Electroweak Precision Measurements