electroweak summary

Electroweak Summary

Chris Hays, Oxford University

for the EWK/BSM session conveners:

Michael Kramer

Dave South

Filip Zarnecki

XVIXVIthth Workshop on Deep Inelastic Scattering Workshop on Deep Inelastic Scattering

London, EnglandLondon, England

April 10, 2008April 10, 2008

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April 10, 2008 Electroweak Summary, DIS 2008 2

Electroweak and Beyond-the-Standard-Model Session

• 42 talks– 17 in this summary, 25 in BSM summary

• 10 additional talks in joint sessions with HFS, SF– 4 in this summary, 6 in HFS/SF summaries

• Many new results shown– Impossible to show all, or to give those shown justice

• 420 minutes in 20 slides

– Apologies to those missed


The Experiments in a Nutshell

• CMS & ATLAS– Looking forward to data!

• ZEUS & H1 & NuTeV– Look at all our data!



• CDF & DØ & NA48/62–Looking forward to more data!






The Electroweak Theory

• Before symmetry breaking: SU(2)L x U(1)Y gauge symmetry

gauge termfermion term

Higgs termYukawa term

• After symmetry breaking: U(1)EM gauge symmetry

kinetic

neutral currentcharged current

Trilinear gauge interaction

Higgs

Higgs-gauge interaction

Quartic gauge interaction

Yukawa


Trilinear Gauge Couplings

• Probe WW vertex with W production at the Tevatron

• t- and u-channels dominate cross section– How do you see the s-channel?





2.6 “dip” significance

Interference effects



Compare data to non-SM trilinear-gauge-coupling predictions

Y. Maravin’s talk

arXiv:0803.0030



• Tevatron only place to separately probe WWZ and WW vertices

• CDF has observed WZ production at the 6 level




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D. Waters’ talk



PRL 98, 161801PRD 76, 111104(R)



• No neutral trilinear couplings in the SM– Tevatron experiments test this prediction with measurements

of Z and ZZ production




are needed to see this picture. Y. Maravin’s talk

arXiv:0712.0599




D. Waters’ talkarXiv:0801.4806

CDF: first measurement of ZZ production

4.4 significance


Neutral Current

• HERA can probe electron and quark neutral current couplings







ZEUS: New measurements ofquark couplings with global fit

K. Nagano’s talk


Neutral and Charged Currents

• NuTeV extracts sin2W using ratio of NC to CC:











Update with fit of s/s asymmetry, K+

e3 BR, d/u PDF uncertainties



Additional effects still to be included:EWK PDF corrections, mc, ...

K. McFarland's talk


Charged Current

• NA48/62 at CERN tests universality of e and CC couplingsQuickTime™ and a

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trigger dominatedbackground dominated





Analysis progressing with 2007 data:use data to constrain → e backgrounds

E. Goudzovski's talk

Preparing for 2011 run to measure BR(K± → ±):QuickTime™ and aTIFF (LZW) decompressor



Charged Current

• HERA probes V-A structure of the charged current with polarized electron beam




K. Nagano’s talk


Charged Current

• Tevatron probes Wtb vertex by measuring W helicity











C. Potter’s talk


Charged Current

• Tevatron directly constrains Vtb with single top production









CDF: t+s = 2.2 ± 0.7 pb (3.7 significance), |Vtb| > 0.66

DØ: t+s = 4.7 ± 1.3 pb (3.6 significance), |Vtb| > 0.68D. Hirschbühl’s talk

LHC: |Vtb| to 5% with 10 fb-1 R. Hawkings' talk


Yukawa Couplings

• Top Yukawa coupling suspiciously close to 1– CDF & DØ have updated their measurements with 2 fb-1

P. Mehtälä's talk

LHC: mt to 1 GeV with 1 fb-1

N. Besson's talk


Yukawa Couplings

• Independently determine top mass from production cross section







mt = 170 ± 7 GeVD. Cho's talk


Kinetic Terms

• Indirectly constrain Higgs mass using Electroweak parameters– Higgs loop corrections to the W mass

New top mass improves consistency with SM mH = 87+36

-27 GeV, mH < 160 (190) GeV

Assuming mt ~ 1 GeV and mW ~ 10 MeV (LHC projections)



N. Besson's talk


Kinetic Terms

• Higgs searches heating up at the Tevatron– Low-mass searches focus on WH, ZH, with H → bb; New: VBF H →

– High-mass searches focus on H → WW

WH ZHVBF H

B. Tuchming's talk

D. Hidas' talk


Kinetic Terms

• LHC experiments have determined combined Higgs sensitivity



D. Fortin's talk



Discovery

Exclusion


The Experiments Revisited

• CMS & ATLAS– Wish we had collision data…

• ZEUS & H1 & NuTeV– Too bad we won’t get any more data…

• CDF & DØ & NA 48/62–Will we get enough data?








Summary

• New results test Electroweak theory at unprecedented level

• Input parameters growing ever more precise

• Rapidly approaching the last piece of the Electroweak puzzle:

The Higgs Boson

“Well, either we’ve found the Higgs boson, or Fred’s just put the kettle on.”


Backup


Tevatron Higgs Sensitivity

• Recent improvements and projections





electroweak summary

Documents

relectroweak summary

missedelectroweak summary

nonsm trilineargauge

charged currentna4862

neutral currenthera

electroweak summarychris

charged currenthera

waters talkarxiv