susy 3 jan kalinowski. j. kalinowskisupersymmetry, part 32 outline linear collider: why? precision...
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SUSY 3
Jan Kalinowski
J. Kalinowski Supersymmetry, part 3 2
Outline
Linear Collider: why?
Precision SUSY measurements at the ILC
masses, couplings, mixing angles, CP phases,
Towards reconstructing the fundamental theory
the SPA Convention and Project
Summary
J. Kalinowski Supersymmetry, part 3 3
After discovering SUSY at LHC
Many burning questions will arise:
• is it really SUSY? (measurement of quantum numbers)
• how is it realized? (MSSM, NMSSM, …)
• how is it broken?
ILC will be indispensable to answer these questions!
Make full use of the flexibilityof the machine:
- tunable energy
- polarized beams
- possibly e-e- and collisions
500200 1000 3000
Sobloher
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An intense R&D process since 1992Huge world-wide effort to be ready for construction in 2009/10(Global Design Effort GDE)
ICFA parameter document:The baseline: - e+e- LC running from MZ to 500 GeV, tunable energy - e- /e+ polarization - at least 500 fb-1 in the first 4 years
Upgrade: to ~ 1 TeV 500 fb-1 /year
Options :- GigaZ (high luminosity running at MZ)- , e, e-e- collisions
Choice of options depending on LHC+ILC physics results
The International Linear Collider
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0. Top quark at threshold• measure its mass, verify its couplings
The ILC physics case
(LHC/ILC study group, `Weiglein et al.)
LHC + LC data analysed together synergy!
1. Higgs• ‘light’ (consistent with precision EW)
verify the Higgs mechanism is at work in all elements• ‘heavy’ (inconsistent with precision EW)
find out why prec. EW data are inconsistent2. 1.+ new states (SUSY, ED, extra Z’, little H,...)
• measurements of new states: masses, couplings• infer properties of states above kinematic limit
3. No Higgs, no new states• find out why precision EW data are inconsistent• look for threshold effects of strong/delayed EWSB
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Masses
Two methods to obtain absolute sparticle masses:
In the continuum At the kinematic threshold
Martyn
smuons:
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Masses
If a double cascade occurs, the intermediate state can be fully reconstructed
e.g.
Assuming neutrino masses known to some extent• two LSP 4-momenta => 8 unknowns• 4 mass relations + E,p conservation => 8 constraints
LSP momenta can be reconstructed
4-momentum of the intermediate particle (here slepton) can be measured!
So if you are used to think that a sparticle is just an edge or an end-point, change your mind – it can be a peak!
Berggren
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Couplings and mixings
EW gauge and Yukawa couplings
can be probed in e.g.
Freitas et al
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Charginos + neutralinos
Including masses and polarized cross sections for light neutralinos:
Now ask your LHC friends to look for => crucial test of the model
Desch, JK, Moortgat-Pick, Nojiri, Polesello
Feeding info on m( ) back to ILC=> improved accuracy
J. Kalinowski Supersymmetry, part 3 10
Neutralino couplings
also the equality of EW gauge and Yukawa couplings can be tested with polarized beams
In these analyses sleptons assumed to be seen at ILC and measured. What if all sfermons heavy, like in focus-point or split SUSY?
Choi, JK, Moortgat-Pick, Zerwas
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Expectations at LHC:• decay dominates, but huge background from top production• other squarks accessible, but low statistics, BG, .. => m=50 GeV• large gluino production, dilepton edge clearly seen, measure
Heavy sfermion case
Focus-point inspired case
sfermions ~ 2 TeV only stop1 ~1.1 TeV
Expectations at ILC 500 GeV• large production, measure its mass precisely• very small cross section for neutralinos• masss from decay + LHC
Desch, JK, Moortgat-Pick, Rolbiecki, Stirling
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Heavy sfermion case
FB asymmetry very sensitive to sneutrino mass
, Z
Desch, JK, Moortgat-Pick, Rolbiecki, Stirling
• obtain sneutrino mass• distinguish models (e.g. focus point SUSY from split SUSY)AFB
Decay lepton FB asymmetry
=>
Even a partial spectrum can tell a lot…
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Majorana and CP of neutralinos
Can be probed in • neutralino pair production at threshold• neutralino decay spectrum near the end-point • neutralino production decay
after Fierz-ing selectron exchanges
+
Production:
Decay:
( intrinsic CP )
If CP conserved, in non-relat. limit
for productionfor decay
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Majorana and CP of neutralinos
CPC: if (12) and (13) in S-wave (23) must be in P-waveotherwise CP violated
• if => P-wave• if => S-wave
1. Production at threshold
JK
2. Compare production of (12) with decay of 2->1
S.Y.Choi
CPC: if production in S-wave decay must be in P-waveotherwise CP violated
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e and options
Create HE photon beam by Compton back-scattering laser light on electrons
Ginzburg, Kotkin, Serbo, Telnov
Photons retain ~90% of electron beam energy almost 100% conversion – no loss of luminosity
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e example
important SM background from
can be considerably suppressed by taking right-handed electron beam
Illian, Monig ’05
signal
E (GeV)
N
Assume that LSP mass=100 GeV and already measured => higher reach in selectron mass
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examples
1. very useful for Higgs boson studies - higher kinematic reach - investigate CP using polarized beams
2. Measure tan(for moderate to large values)
- important parameter - notoriuosly difficult to determine
Choi, JK, Lee, Muhlleitner, Spira, Zerwas
J. Kalinowski Supersymmetry, part 3 18
Cosmology connection: benchmarks
How well <v> can be predicted from LHC/ILC depends on model for NP American LCC + Snowmass05 benchmark points
Peskin, LCWS06
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LCC2
Squarks and sleptons heavy, relevant param. M1, M2, tan
J. Alexander et al.
LHC alone allows multiple solutions
Need to know gaugino-higgsino mixing anglecan be measured at ILC ILC
resolves
measured at LHC
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LCC2: cross-checks, predictions
• rate of from DM annihilation in the galactic center, or using measured rate determine the DM density
• neutralino-proton cross section for direct DM search experiments, or using measured cross section determine the flux of DM
With the LSP properties determined, calculate
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The LHC will start testing cosmology.
other LCC points
In some cases the LC will be invaluable.
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Towards reconstructing SUSY:
Supersymmetry particles will be discovered at the LHC
Future ILC will provide additional precision data on masses and couplings
Will everybody be happy?
We would like to know the relation of the visible sector to the fundamental theory: what is the origin of SUSY breaking ?
what is the role of neutrinos ? is it related to the theory of early universe ? how to embed gravity ? etc., etc.
Probably we won’t have a direct experimental access to these questions
But SUSY is a predictive framework !
We can analyse precision data and state how well within some specific SUSY/GUT
model the relation of observable to fundamental physics can be establishedYou may ask: who cares about precision ??
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Remember Tycho Brache ?
from W. Kilian
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Practical questions
How precisely can we predict masses, cross sections, branching ratos, couplings etc. ?
many relations between sparticle masses already at tree-level, much worse at loop-level no obvious choice of renormalizaton scheme
Goals of the SPA Project
Lagrangian parameters not directly measurable
some parameters are not directly related to one particular observable, e.g., tan, fitting procedure, ....
What precision can be achieved on parameters of the MSSM Lagrangian ?
unification of couplings, soft masses etc.??? which SUSY breaking mechanism ??
Can we reconsruct the fundamental theory at high scale ?
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http://spa.desy.de/spa
The SPA project is a joint study of theorists and experimentalists working on LHC and Linear Collider phenomenology. The study focuses on the supersymmetric extension of the Standard Model. The main targets are
•High-precision determination of the supersymmetry Lagrange parameters at the electroweak scale •Extrapolation to a high scale to reconstruct the fundamental parameters and the mechanism for supersymmetry breaking
The SPA convention and the SPA Project are described in the SPA reportSPA report, ,
Eur.Phys.J.C46:43-60,2006 [arXiv:hep-ph/05113444].
Spiritus movens: Peter Zerwas
J. Kalinowski Supersymmetry, part 3 26
The Document
More than one ‘astronomer’ involved
Please join in !!!!
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Summa summarum
Supersymmetry has been motivated as a way to stabilize the
hierarchy
At present: no sign, but not excluded either
If true, exciting times at near-future colliders
Precision measurements will be necessary to reconstruct the
theory
Once seen and studied, it may provide a telescope to physics
at GUT/Planck/string scales