Prospects for (non-SUSY) new physics with first LHC data

Jonathan Butterworth University College London & ATLAS on behalf of ATLAS & CMS PASCOS 2007, Imperial 3rd July 2007

Jon Butterworth, PASCOS07 1 Introduction

• Large Hadron Collider will provide proton-proton collisions at 14 TeV – factor of 7 above previous colliders.

Jon Butterworth, PASCOS07 2 Introduction

• Large Hadron Collider will provide proton-proton collisions at 14 TeV – factor of 7 above previous colliders. • Not just “any old” new energy regime: first direct look at physics far above the electroweak-symmetry-breaking scale. – unitarity violation around 1.2 TeV if the SM is treated as a Higgsless low-energy effective theory. – must see either the SM Higgs, or other new physics, or both.

Jon Butterworth, PASCOS07 3 Introduction

• First data next summer – no early low energy run

Jon Butterworth, PASCOS07 4 Introduction

• First data next summer – no early low energy run • Consider here the prospects for new physics (excluding SUSY) with a few fb-1 of data. – cross sections of a few 100 fb or less – clear & fairly simple signatures

Jon Butterworth, PASCOS07 5 Introduction

• First data next summer – no early low energy run • Consider here the prospects for new physics (excluding SUSY) with a few fb-1 of data. – cross sections of a few 100 fb or less – clear & fairly simple signatures • Precision comparison of SM model tails will take longer – need luminosity and very good understanding of detector calibrations, resolutions etc. • Signature rather than model based

Jon Butterworth, PASCOS07 6 Outline

• Resonances everywhere – Z' , UED etc • Missing Momentum + X – W', UED etc • Jets etc – Contact interactions, t' etc – Slight digression, single jet mass & substructure • Vector boson resonances – Dynamical EWSB etc • Multijet & Lepton (Black holes etc)

Jon Butterworth, PASCOS07 7 Z' -> Dimuon

• Search for µ+µ− resonance above the Drell-Yan background

Jon Butterworth, PASCOS07 8 Z' -> Dimuon

• Search for µ+µ− resonance CMS above the Drell-Yan background

• Example: E6/ SO(10) Zη

• 0.1 fb-1 data for normalisation • Assumes perfect detector

CMS Physics TDR CERN/LHCC 2006­021 Jon Butterworth, PASCOS07 9 Z' -> Dimuon

• Search for µ+µ− resonance CMS above the Drell-Yan background

• Example: E6/ SO(10) Zη

• 0.1 fb-1 data for normalisation • Assumes perfect detector • If include realistic “100pb-1” detector alignment. • Less clear, but still

CMS Physics TDR CERN/LHCC 2006­021 observable. Jon Butterworth, PASCOS07 10 Z' -> Dimuon Sensitivity to various CMS • scenarios as a function of luminosity. • Also ~applies to KK gravitons (RS model). • Begin to distinguish spin-1 from spin-2 with ~50 fb-1 • NB: dimuon channel is best for CMS, dielectron best for ATLAS.

CMS Physics TDR CERN/LHCC 2006­021 Jon Butterworth, PASCOS07 11 Diphoton searches • Graviton resonance in RS extra dimension models. CMS – Decay to two photons

CMS Physics TDR CERN/LHCC 2006­021. Lemaire, Litvin, Newman CMS NOTE­2006/051. Jon Butterworth, PASCOS07 12 Diphoton searches • Graviton resonance in RS extra dimension models. CMS – Decay to two photons

CMS Physics TDR CERN/LHCC 2006­021. Lemaire, Litvin, Newman CMS NOTE­2006/051. Jon Butterworth, PASCOS07 13 Top resonances searches

• Kaluza-Klein excitation of gluon in TeV-1 extra dimension models. • 1 TeV resonance decaying to top, one W->hadrons, other to (e or µ) + ν.

Jon Butterworth, PASCOS07 14 Top resonances searches

ATLAS • Kaluza-Klein excitation of gluon in TeV-1 extra dimension models. • 1 TeV resonance decaying to top, one W->hadrons, other to (e or µ) + ν. • Shown for 3 fb-1 • Sensitivity in this channel

ATL­PHYS­PUB­2006­002, March, Ros & Salvachua eventually up to 3.3 TeV

Jon Butterworth, PASCOS07 15 Lepton + Missing p T • Benchmark against W' models, as in the dilepton case for Z'. • Discovery based on transverse mass (M ). T

Jon Butterworth, PASCOS07 16 Lepton + Missing p T • Benchmark against W' models, as CMS in the dilepton case for Z'. • Discovery based on transverse mass (M ). T

CMS Physics TDR CERN/LHCC 2006­021. Hof, Hebbeker, Hoepfner, CMS NOTE­2006/117. W' reference model, Altarelli , Mele, Ruiz­Altaba, Z. Phys. C45 (1989) 109.

Jon Butterworth, PASCOS07 17 Lepton + Missing p T • Benchmark against W' models, as CMS in the dilepton case for Z'. • Discovery based on transverse mass (M ). T CMS

CMS Physics TDR CERN/LHCC 2006­021. Hof, Hebbeker, Hoepfner, CMS NOTE­2006/117. W' reference model, Altarelli , Mele, Ruiz­Altaba, Z. Phys. C45 (1989) 109.

Jon Butterworth, PASCOS07 18 KK gluon -> 4l + Missing p T • 2 separate lepton pairs from decay chain of gluon excitation • • Missing p from escaping photon • T excitation (stable due to KK- parity conservation).

Jon Butterworth, PASCOS07 19 KK gluon -> 4l + Missing p T CMS • 2 separate lepton pairs from decay chain of gluon excitation • • Missing p from escaping photon • T excitation (stable due to KK- parity conservation). • Sensitive up to around 700 GeV in radius of extra dimensions with first few fb -1 M. Kazana, CMS CR 2006/062 Jon Butterworth, PASCOS07 20 Dijets CMS • Cross section measurement quite quickly limited by systematics. – error bars shown for 10fb-1

CMS Physics TDR CERN/LHCC 2006­021 Jon Butterworth, PASCOS07 21 Dijets CMS • Cross section measurement quite quickly limited by systematics. – error bars shown for 10fb-1 • Ratios in different rapidity regions have sensitivity to scale of new physics (contact interactions). Systematics cancel in ratio. • Also sensitivity to dijet

CMS Physics TDR CERN/LHCC 2006­021 resonances. Jon Butterworth, PASCOS07 22 Jets, W, top...

• A qualitatively new feature at the LHC is abundance of particles with mass O(100) GeV and p of several hundred GeV decaying T to hadrons (W,Z,top,h?).

Jon Butterworth, PASCOS07 23 Jets, W, top...

• A qualitatively new feature at the LHC is abundance of particles with mass O(100) GeV and p of several hundred GeV decaying T to hadrons (W,Z,top,h?). • Decay products appear in the same jet. – Measure single-jet mass – Look at the jet substructure for signs of the heavy particle decay. • Exploit this in searches & diagnosis of new physics...

Jon Butterworth, PASCOS07 24 Jets, W, top...

• ... example from WW scattering: • At high WW mass (guaranteed new physics)

Jon Butterworth, PASCOS07 25 Jets, W, top...

• ... example from WW scattering: • At high WW mass (guaranteed new physics)

Jet p > 300 • T GeV. • Note visible W JMB, Cox, Forshaw, Phys. Rev. D65; 096014 (2002); and top peaks S. Allwood, Manchester PhD Thesis 2006, E. Stefanidis, UCL PhD Thesis 2007.

Jon Butterworth, PASCOS07 26 Jets, W, top...

• ... example from WW scattering: • At high WW mass (guaranteed new physics)

Jet p > 300 • T GeV. • Note visible W JMB, Cox, Forshaw, Phys. Rev. D65; 096014 (2002); and top peaks S. Allwood, Manchester PhD Thesis 2006, E. Stefanidis, UCL PhD Thesis 2007. • Studies show sensitivity with a few fb-1

Jon Butterworth, PASCOS07 27 Jets, W, top...

• Other possibilities: – W from high mass t'

Holdom, JHEP 0703:063,2007. Skiba & Tucker­Smith Phys.Rev.D75:115010,2007.

Jon Butterworth, PASCOS07 28 Jets, W, top...

• Other possibilities: – W from high mass t' – KK gluon and/or graviton – (SUSY diagnosis)

Holdom, JHEP 0703:063,2007. Skiba & Tucker­Smith Phys.Rev.D75:115010,2007. Lillie, Randall, Wang hep­ph/0701166; Fitzpatirck, Kaplan, Randall, Wang, hep­ph/0701150. JMB, Ellis, Raklev, JHEP 05: 033, 2007.

Jon Butterworth, PASCOS07 29 Jets, W, top...

• Need good single-jet-mass and subjet resolution, which seems possible:

ATLAS Jet/ETMiss group A. Davison, JMB

Jon Butterworth, PASCOS07 30 Jets, W, top...

• Need good single-jet-mass and subjet resolution, which seems possible:

ATLAS Jet/ETMiss group A. Davison, JMB

Jon Butterworth, PASCOS07 31 Vector boson resonances

• Generic feature of new strong interactions around ~1 TeV • Example, WZ resonance in Technicolour model.

Jon Butterworth, PASCOS07 32 Vector boson resonances CMS • Generic feature of new strong interactions around ~1 TeV • Example, WZ resonance in Technicolour model. • Again, first sensitivity with a few fb-1

CMS Physics TDR CERN/LHCC 2006­021 Kreuzer, CMS NOTE­2006/135.

Jon Butterworth, PASCOS07 33 Multiple jets & particles • Low Planck scale in extra dimension models may lead to copious production of mini black- holes. • Decay via Hawking radiation to states with “flavour democratic” high multiplicity states.

Jon Butterworth, PASCOS07 34 Multiple jets & particles CMS • Low Planck scale in extra dimension models may lead to copious production of mini black- holes. • Decay via Hawking radiation to states with “flavour democratic” high multiplicity states. • Cuts on mulitplicity & event shapes (circularity).

Sphericity CMS Physics TDR CERN/LHCC 2006­021

Jon Butterworth, PASCOS07 35 Multiple jets & particles • Low Planck scale in extra ATLAS dimension models may lead to copious production of mini black- holes. • Decay via Hawking radiation to states with “flavour democratic” high multiplicity states. • Cuts on mulitplicity & event shapes (circularity). • Visible with very low luminosity Tanaka, Yamamura, Asai, Kanzaki SN­ATLAS­2005­048, Eur. Phys. J. C 41 (2005) s19­s33 once detector/ backgrounds Jon Butterworth, PASCOS07 understood! 36 Summary

• Many surprises possible in the early days (first year).

Jon Butterworth, PASCOS07 37 Summary

• Many surprises possible in the early days (first year). • “Bonfire of models” is certain, some (one?) will survive.

Jon Butterworth, PASCOS07 38 Summary

• Many surprises possible in the early days (first year). • “Bonfire of models” is certain, some (one?) will survive. • I have not discussed at all the enormous complexity of the detectors and the huge challenges involved in understanding them, and in understanding the standard model at 14 TeV.

Jon Butterworth, PASCOS07 39 Summary

• Many surprises possible in the early days (first year). • “Bonfire of models” is certain, some (one?) will survive. • I have not discussed at all the enormous complexity of the detectors and the huge challenges involved in understanding them, and in understanding the standard model at 14 TeV. • The first things we see will be features of new detectors. Buyer beware rumours & blogs!!

Jon Butterworth, PASCOS07 40 Summary

• Many surprises possible in the early days (first year). • “Bonfire of models” is certain, some (one?) will survive. • I have not discussed at all the enormous complexity of the detectors and the huge challenges involved in understanding them, and in understanding the standard model at 14 TeV. • The first things we see will be features of new detectors. Buyer beware rumours & blogs!! • Nevertheless, there will be some really exciting physics...

Jon Butterworth, PASCOS07 41