# Presentation: 802055

## 

BEYOND THE STANDARD MODEL AT THE TEVATRON?
	OR, WHAT YOU SEE OFTEN DEPENDS ON WHAT YOU LOOK FOR	

						Gordy Kane
						Fermilab
						Oct 2006

*BEYOND THE STANDARD MODEL AT THE TEVATRON?*
- 	OR, WHAT YOU SEE OFTEN DEPENDS ON WHAT YOU LOOK FOR
- 						Gordy Kane
- 						Fermilab
- 						Oct 2006

## 
Introduction/perspectives

(More general) supersymmetry signatures

Is it susy?

- Introduction/perspectives
- (More general) supersymmetry signatures
- Is it susy?

## String theory is exciting because it’s a framework that addresses how to explain why the SM particles and forces are what they are, it incorporates all the forces in a quantum theory, and it addresses many questions the SM cannot address
Why and how is the electroweak symmetry of the SM broken?
Why is parity not conserved?
What is the dark matter? 
How does the matter asymmetry originate?
Why are there families of particles?
How is supersymmetry broken?
How does the hierarchy between the weak scale and the string scale or gravity arise?
What caused inflation

Most other approaches to physics BTSM address few or none of these, and have little or no theoretical motivation

- Why and how is the electroweak symmetry of the SM broken?
- Why is parity not conserved?
- What is the dark matter?
- How does the matter asymmetry originate?
- Why are there families of particles?
- How is supersymmetry broken?
- How does the hierarchy between the weak scale and the string scale or gravity arise?
- What caused inflation
*Most other approaches to physics BTSM address few or none of these, and have little or no theoretical motivation*

## The natural scale for string theory is at or above the unification scale, of order 1016 GeV– but we need to connect it with experiment 

Supersymmetry stabilizes our scale against quantum corrections from this high scale, in a perturbative theory that allows us to relate physics at the two scales – and
It provides a candidate for dark matter
It may explain electroweak symmetry breaking perturbatively
It implies accurate unification of force strengths so the idea of a simple, unified description of forces can make sense
It provides ways to explain the matter asymmetry
–  let’s us make string based predictions for LHC and Tevatron and other low scale data (EDMs, DM, rare decays...)
–  let’s us extrapolate collider and other low scale data to the string scale and get clues to stringy physics
–  is suggested by string theory solutions

SO WE CAN TRY TO STUDY AND TEST STRINGY PHYSICS IN A SUPERSYMMETRIC WORLD

- Supersymmetry stabilizes our scale against quantum corrections from this high scale, in a ***perturbative*** theory that allows us to relate physics at the two scales – *and*
- It provides a candidate for dark matter
- It may explain electroweak symmetry breaking perturbatively
- It implies accurate unification of force strengths so the idea of a simple, unified description of forces can make sense
- It provides ways to explain the matter asymmetry
- –  let’s us make string based predictions for LHC and Tevatron and other low scale data (EDMs, DM, rare decays...)
- –  let’s us extrapolate collider and other low scale data to the string scale and get clues to stringy physics
- –  is suggested by string theory solutions
- SO WE CAN TRY TO STUDY AND TEST STRINGY PHYSICS IN A SUPERSYMMETRIC WORLD

## Let’s assume the world is simple and understandable, and that we can answer or at least address all the basic questions – of course it could be more complicated, but why give up the simple and comprehensive picture until we are forced to??

So – assume we live in the best of all possible string vacua – supersymmetric one(s) – optimism about discoveries and understanding well justified

- So – assume we live in the best of all possible string vacua – supersymmetric one(s) – optimism about discoveries and understanding well justified

## General picture suggests/predicts 

light Higgs boson, lighter than about 200 GeV in a general supersymmetric theory
-- two independent (indirect) experimental confirmations
No deviation from SM predictions at LEP unless superpartners directly seen
Unification of gauge couplings at high scale
Cold dark matter swimps

OK!

Main test – superpartners exist around EW scale

- light Higgs boson, lighter than about 200 GeV in a general supersymmetric theory
- -- two independent (indirect) experimental confirmations
- No deviation from SM predictions at LEP unless superpartners directly seen
- Unification of gauge couplings at high scale
- Cold dark matter swimps
- OK!
- Main test – superpartners exist around EW scale

## 
So default should be to focus resources on supersymmetry searches

***So default should be to focus resources on supersymmetry searches***

## Are there light superpartners to detect at Tevatron? 

## Are there light superpartners to detect at Tevatron? 
Assume ILC with total energy 500 GeV can produce new particles – then very likely Tevatron can too
	 at FNAL no need to argue for light superpartners

Tevatron can also produce light gluinos, up to few hundred GeV – good theoretical motivation for light gluinos    [Theory motivated benchmark models and superpartners at the Tevatron. G.L. Kane, Joseph D. Lykken, Stephen Mrenna, Brent D. Nelson, Lian-Tao Wang, Ting T. Wang, Phys.Rev.D67:045008,2003; hep-ph/0209061, and also recent stringy model building] 

- Assume ILC with total energy 500 GeV can produce new particles – then very likely Tevatron can too
- 	 at FNAL no need to argue for light superpartners
- Tevatron can also produce light gluinos, up to few hundred GeV – good theoretical motivation for light gluinos    [Th**eory motivated benchmark models and superpartners at the Tevatron.** _[G.L. Kane](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Kane,G.L.%22)_, _[Joseph D. Lykken](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Lykken,%20JosephD.%22)_, _[Stephen Mrenna](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Mrenna,%20Stephen%22)_, _[Brent D. Nelson](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Nelson,%20BrentD.%22)_, _[Lian](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Wang,%20Lian-Tao%22)__[-Tao Wang](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Wang,%20Lian-Tao%22)_, _[Ting T. Wang](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Wang,%20TingT.%22)_, **Phys.Rev.D67:045008,2003; hep-ph/0209061, ****and also recent stringy model building****]**

## Are there light superpartners to detect at Tevatron? 
Assume ILC with total energy 500 GeV can produce new particles – then very likely Tevatron can too
	 at FNAL no need to argue for light superpartners

Tevatron can also produce light gluinos, up to few hundred GeV – good theoretical motivation for light gluinos    [Theory motivated benchmark models and superpartners at the Tevatron. G.L. Kane, Joseph D. Lykken, Stephen Mrenna, Brent D. Nelson, Lian-Tao Wang, Ting T. Wang, Phys.Rev.D67:045008,2003; hep-ph/0209061, and also recent stringy model building] 

If LHC finds light superpartners that could have been found at the Tevatron...

- Assume ILC with total energy 500 GeV can produce new particles – then very likely Tevatron can too
- 	 at FNAL no need to argue for light superpartners
- Tevatron can also produce light gluinos, up to few hundred GeV – good theoretical motivation for light gluinos    [Th**eory motivated benchmark models and superpartners at the Tevatron.** _[G.L. Kane](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Kane,G.L.%22)_, _[Joseph D. Lykken](http://www.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Lykken,%20JosephD.%22)_, Stephen Mrenna, Brent D. Nelson, Lian-Tao Wang, Ting T. Wang, **Phys.Rev.D67:045008,2003; hep-ph/0209061, ****and also recent stringy model building****]**
- If LHC finds light superpartners that could have been found at the Tevatron...

## Parameters? -- So far no parameters with dimensions of mass calculable from first principles – in SM must measure all quark and lepton masses, and higgs mass (or vev) – same in supersymmetry

Supersymmetry full Lagrangian quantum field theory –  gauge couplings same as for the SM, known – families, so more possible (complex) masses than in SM, so more parameters

Imagine high scale underlying theory – still can’t calculate masses, but high scale theory has few mass parameters – then can calculate all the mass parameters of supersymmetry in terms of those few

Also, any particular physics only sensitive to subset of parameters

Also, same parameters at hadron colliders, rare decays, DM ...

- Supersymmetry full Lagrangian quantum field theory –  gauge couplings same as for the SM, known – families, so more possible (complex) masses than in SM, so more parameters
- Imagine high scale underlying theory – still can’t calculate masses, but high scale theory has few mass parameters – then can calculate all the mass parameters of supersymmetry in terms of those few
- Also, any particular physics only sensitive to subset of parameters
- Also, same parameters at hadron colliders, rare decays, DM ...

## Are there problems with this picture?

Could have found effects by now in gμ-2, FCNC – most do show 1.5-2.5 σ effects – squarks, sleptons in loops so perhaps clue that these are heavier than ~ 1 TeV – note recent Becher and Neubert analysis of bs γ “This opens a window for significant New Physics contributions in rare radiative B decays” 

EDMs too small? – problem only if assume phases random  parameters ~1, but that’s unlikely if an underlying theory – would be great if one could learn all observable phases ~0 

Given experimental constraints, and radiative EWSB for Higgs physics, should have found mh100 GeV – serious fine tuning??
	-- only in MSSM 
	-- LEP limits not general 
	-- fine tuning smaller if light gluinos
	-- accident? – e.g. 4sin2θW-1 << 1 for sin2θ=0.23

		Maybe, but not clear there are any problems

- Could have found effects by now in gμ-2, FCNC – most do show 1.5-2.5 σ effects – squarks, sleptons in loops so perhaps clue that these are heavier than ~ 1 TeV – note recent Becher and Neubert analysis of bs γ “This opens a window for significant New Physics contributions in rare radiative B decays”
- EDMs too small? – problem only if assume phases random  parameters ~1, but that’s unlikely if an underlying theory – would be great if one could learn all observable phases ~0
- Given experimental constraints, and radiative EWSB for Higgs physics, should have found mh100 GeV – serious fine tuning??
- 	-- only in MSSM
- 	-- LEP limits not general
- 	-- fine tuning smaller if light gluinos
- 	-- accident? – e.g. 4sin2θW-1 << 1 for sin2θ=0.23
- 		Maybe, but not clear there are any problems

## 
How do we find a signal BTSM ?? 

The experts are experimenters + SM theorists, simulators

They will get it right wherever they look carefully

Many places to look – where you look is crucial

- How do we find a signal BTSM ??
- The experts are experimenters + SM theorists, simulators
- They will get it right wherever they look carefully
- Many places to look – where you look is crucial

## What are good signatures of supersymmetry?
		(Datta, GK, Toharia hep-ph/0510204)

Should be very phenomenological, unbiased
Form of supersymmetry need not be MSSM – will contain MSSM so MSSM spectrum will be there, but MSSM constraints need not be
Do NOT impose EWSB, lower limit on DM relic density, rare decays, g-2, etc – all are very model dependent
No general lower limit on LSP mass exists
Don’t assume gaugino mass unification (7-2-1at low scale) -- not so likely at high scale in string theories, can have different RGE running, puts artificial lower limit on gluino mass

These don’t directly affect search for BTSM signal, but may lead one to not focus on all good signals

- 		(Datta, GK, Toharia hep-ph/0510204)
- Should be very phenomenological, unbiased
- Form of supersymmetry need not be MSSM – will contain MSSM so MSSM spectrum will be there, but MSSM constraints need not be
- Do NOT impose EWSB, lower limit on DM relic density, rare decays, g-2, etc – all are very model dependent
- No general lower limit on LSP mass exists
- Don’t assume gaugino mass unification (7-2-1at low scale) -- not so likely at high scale in string theories, can have different RGE running, puts artificial lower limit on gluino mass
- These don’t directly affect search for BTSM signal, but may lead one to not focus on all good signals

## Some very good signatures – presumably Run2 papers on all of them by now...
Same-sign dileptons, or same-sign t or b
		-- but suppressed if charginos heavy, or if LH squarks > gluinos      	   > RH squarks, or  gluinos  g+LSP  [HK 1984, TW]

Trileptons 
		-- but suppressed if N2 decays radiatively or to sneutrino +   	   neutrino

Large missing transverse energy

b-rich events if stop or sbottom lighter than other squarks

Recent string model building suggests light gaugino masses (gluinos, charginos, neutralinos) – all could be in tevatron range with few fb-1

- Same-sign dileptons, or same-sign t or b
- 		-- but suppressed if charginos heavy, or if LH squarks > gluinos      	   > RH squarks, or  gluinos  g+LSP  [HK 1984, TW]
- Trileptons
- 		-- but suppressed if N2 decays radiatively or to sneutrino +   	   neutrino
- Large missing transverse energy
- b-rich events if stop or sbottom lighter than other squarks
- Recent string model building suggests light gaugino masses (gluinos, charginos, neutralinos) – all could be in tevatron range with few fb-1

## But if the more obvious signals are not there, the events more into different categories

##   

Note single lepton and trijet signals more robust 

- Note single lepton and trijet signals more robust

## 
Is it susy?

- Is it susy?

## 
Is it susy?
	 (Datta, GK, Toharia, hep-ph/0510204) 

Can we tell various models with KK excitations, etc from susy after a signal is found?

Can we tell susy from something we haven’t yet thought of?

At hadron colliders?

I think so...

- Is it susy?
- 	 (Datta, GK, Toharia, **hep-ph/0510204)**
- Can we tell various models with KK excitations, etc from susy after a signal is found?
- Can we tell susy from something we haven’t yet thought of?
- At hadron colliders?
- I think so...

## 
Cross sections determined by mass, spin, charges – measure mass kinematically, and measure or know charges for a given model  spin

So can distinguish spin 0, 1⁄2, 1,... and therefore models, at hadron collider

[measure top spin same way  spin 1⁄2]

Basic method robust, may need work for some mass patterns

- Cross sections determined by mass, spin, charges – *measure mass* kinematically, and measure or know charges for a given model  spin
- So can distinguish spin 0, 1⁄2, 1,... and therefore models, at hadron collider
- [measure top spin same way  spin 1⁄2]
- Basic method robust, may need work for some mass patterns

## Slide 22

## Also, BR -- fix spectrum as same for MSSM, UED, and fix gluino decay BR  to be same as gluon recurrence BR

Then: 				MSSM		UED

And signature fractions:
   OS 2 lepton
   SS 2 lepton
   trilepton

- Then: 				MSSM		UED
- And signature fractions:
-    OS 2 lepton
-    SS 2 lepton
-    trilepton

## So experimental program whose goals are physics BTSM should strongly emphasize
Find superpartners if they are there – look broadly and systematically

Lab dark matter detectors
Signals that require new weak scale particles or significantly constrain approaches
	-- EDMs
	-- FCNC rare decays or those with large non-SM   	windows (g-2, μ->e γ, etc)

- Find superpartners if they are there – look broadly and systematically
- Lab dark matter detectors
- Signals that require new weak scale particles or significantly constrain approaches
- 	-- EDMs
- 	-- FCNC rare decays or those with large non-SM   	windows (g-2, μ->e γ, etc)

## 
What if LHC makes discoveries first?

Tevatron data often adds info, probes different info

- What if LHC makes discoveries first?
- Tevatron data often adds info, probes different info

## Suppose a susy signal – very difficult to deduce nature of LSP at hadron collider – leptons soft – flippers, etc – assume squark and gluino masses measured
Several ways to remove higgsino/wino LSP degeneracy by observing other channels, e.g. using Tevatron data!

					 Note quark partons, better at tevatron

- Several ways to remove higgsino/wino LSP degeneracy by observing other channels, e.g. using Tevatron data!
- 					 Note quark partons, better at tevatron

- Light gluino

- Light squark

## 
Good theoretical and phenomenological motivation for light superpartners, particularly gluinos, charginos, neutralinos – in Tevatron range

Best signatures not known because cannot calculate masses from first principles yet – so examine all signatures thoroughly

- Good theoretical and phenomenological motivation for light superpartners, particularly gluinos, charginos, neutralinos – in Tevatron range
- Best signatures not known because cannot calculate masses from first principles yet – so examine all signatures thoroughly

## 
CPV AT HADRON COLLIDERS

Doesn’t matter if initial state CP invariant – just calculate SM baseline
Similarly, doesn’t matter if detector invariant
Can study with leptons in final state – study triple scalar products etc
Can use jet charges for light quarks (u,d) and for gluons to greatly increase statistics – done at LEP – I am confident it can be done with appropriate jets at hadron colliders

- CPV AT HADRON COLLIDERS
- Doesn’t matter if initial state CP invariant – just calculate SM baseline
- Similarly, doesn’t matter if detector invariant
- Can study with leptons in final state – study triple scalar products etc
- Can use jet charges for light quarks (u,d) and for gluons to greatly increase statistics – done at LEP – I am confident it can be done with appropriate jets at hadron colliders