Supersymmetry at LHC and beyond

---Ultimate tagets---Mihoko M. Nojiri YITP, Kyoto University

Why collider ?? Why collider ??

Best way to 1. See existence of superpartners2. Supersymmetric relations3. Soft mass measurementsUnderstand SUSY breaking mechanism Interactions at high scaleImpacts on the other physics B, LFV, Dark matter

1. The existence1. The existence

Large cross section. No SM backgrounds

Search up to 2TeV squark or gluino.

1000 events/year for 1TeV squarks and gluinos

We should try to extract ALL physics information from THIS experiment!

scaler mass

ga

ug

ino

mas

s

(Not only) famous SPS1a …

2. Supersymmetric relations (I can’t wait until LC operation)

chiral nature No new dimensionless coupling Fermion-sfermion-gaugino(higgsinocoupling)

BffBWff RRLL

~~),

~(

~~

Lt~

H~

tYLt

~

W~

2g

RtLt

chirality and m(jl) distributions Richardson (2001), Barr(2004), Kawagoe Goto Nojiri(2004)

Chirality of slepton appears in m(jl) distribution Right handed lepton goes same direction to the jet d

irection Right handed anti-lepton goes opposite to jet

Charge asymmetry!

LqLq~0

2~

Rl

Rl

MC simulations (left and right sleptons)

GeV230)(

~~ 02

qlm

lqlqq LL

GeV380)(

~~ 02

qlm

lqlqq RL

Kawagoe, Goto, Nojiri(2004)

smuon L-R mixing(Goto’s talk)

22

22

222

~

22

~

1

)(

)(

:asymmetry andWidth

/sin

/tancos

:couplings ofn competitio

cossin~ :mixing

RLlA

RLl

mNgR

mmNgL

ZBY

LW

LR

tan Br(e) Br()/Br(e) A()

10 6.3% 1.04 0.93

15 2.4% 1.09 0.83

20 1.2% 1.17 0.70

visible in wide parameter regionsProof of smuon F term mixing Other examples?( m(bb) distribution of gluino->stop top) Hisano, Kawagoe,MMN 2003

3.Soft mass measurement Collider signature of SUSY “easy” to “hard”

3.Soft mass measurement Collider signature of SUSY “easy” to “hard”

Long lived NLSP(~O(10m))

Neutral LSP sfermion<gaugino gaugino<sfermion gaugino<<sfermion degenerated

Too heavy

Models Gauge mediation Supergravity and the v

ariants M>m M~m M<<m

KK

“Easy case”Signature with long lived NLSP Shorter life time (<O(1cm)) lots of leptons and photons endpoint analysis. Charged Long Lived NLSP

TOF for charged track t~1ns at 10m-20m

Full reconstruction Neutral Long Lived NLSP

No track Fine time resolution at ECAL ct~

3cm at O(1m) Gravitino momentum and decay p

osition can be solved with the time info

(Kobayasi, Kawagoe, Ochi,MMN(2003)

Kawagoe’s talk) No systematic study yet.

Hinchliffe and Paige

　“Moderate　 cases” 　“Moderate　 cases”

Long lived NLSP(~O(10m))

Neutral LSP sfermion<gaugino(2 body) gaugino<sfermion(3 body ) gaugino<<sfermion degenerated

Too heavy

Time delay Signals TOF for charged track Arrival time(photon)

Endpoint analysis(Giacomo’s talk)

Lepton mode Tau and b modes Jet selection

No good ideas

Summary of endpoint study at SPS1a

Based on the endpoint analysis, sparticle masses may be understood very well. The lepton channels are important.

LSP mass dark matter massSlepton mass, neutralino mass Dark matter density

Limitations of the end point method Limitations of the end point method

unkonwn LSP momentum No kinematical constraint eve

n though you know the masses

Waste of statistics Events off the end points are

not used. Need statistics enough to see

the end point. signals from different casca

des to make a single broad end point.

Mass relation method apply mass-shell constraints to solve events Mass relation method apply mass-shell constraints to solve events Full event reconstructions! we

see peaks. Use all events for mass and

distribution study. “In principle”, a few events are

enough to determine the masses and LSP momentum (up to jet energy resolutions)

Kinematical constraints available.

Nojiri, Polesello, Tovey hep-ph/0312318 (Les Houches)

Example of mass relation method

sbottom mass

glu

ino

ma

ss

Each event corresponds to a curve in the mass planeTwo events is enough to give the masses, and LSP momentum. distribution of the solution in the previous plot

llbblbblbbbbg 01

02

~~~~~

For simplicity Assume we know mass of

l~

,, 02

01

Dim mass space MA event<-> 4 dim hypersurface in M

Sbottom mass determination (plot lighter solution for fixed gluno mass)

GeV GeV GeV

Kawagoe, MMN, Polesello…

Background level

Sbottom2 contribution

tan tanb=15 tanb=20

mSUGRA and 3rd generation mass spectrummSUGRA and 3rd generation mass spectrum FCNC constraints are weak for 3rd generation. 　　 non-universal squark and slepton masses for the 3rd g

eneration. Yukawa RGE running breaks the universality at at the

GUT scale. m(stop,sbottom)<m(1st) Left-right squark mixing SPS1a tanb=10 sbottom mass 492GeV tanb=20 479GeV

Implication to higgs mass, B physics….

A event probability density for true masses(L)

log L(1) + logL(2) + log L(3)+ logL(4)

= log L(~2)

tan=10 tan=20

signals ~

2bsignal

~ LL event withcut 2cut b

dependencecut weak

GeV6.70 input

GeV1.66 fit m

Spin off from the mass relation methodSpin off from the mass relation method

TmissTT Ppp

)2()1(

reconstructed LSPmomentum

Total missing momentum

Transverse momentum of the 2nd LSP

2nd LSP•For the 2nd LSP, transverse Momentum is known•a event Corresponds to 1 dim line in the mass space. •Even shorter cascade can be solved.

Neutralino momentum also solved.

New channelsNew channels using missing pT (hep-ph/0312317,18) using missing pT (hep-ph/0312317,18)

Example I

chargino reconstruction

01

01

02

01

011

~~~~~

~~~~

jlllljjq

jjjjWjq

.

Example II heavy higgs reconstruction 4lepton channel

llll

H01

02

02

02

~~~

~~

“getting more difficult” “getting more difficult”

Large tan gaugino<sfermion

squark->gluino jets Then 3 body Losing statistics

Tau mode dominate. (giacomo’s talk) All squarks decays into gl

uino, information loss Jet selection? B mode

s?

•Degenerated (no hard jets…)

Handle signal without leptons

Sometimes SUSY signature is not hard leptons. Still stop, sbottom may be lighter than other sparticles due to top Yukawa RGE SUSY -> events with many b jets. Gluino decays dominantly into bt ,bband tt b tagging efficiency is 60% Looking for non-b jets from SUSY decay is difficult. many QCD jets

Reconstructing top from gluino decays

t bW bjj N(jet) 7 typically. Many BG to W jj Background to t bWbjjis estim

ated from events in the sideband

mjj<mW-15GeV

mjj>mW+15 GeV. Reconstructed top quarks are us

ed to study tb distribution .

Difference between two body and three body

Branching ratio is biggest for tb final state.

SPS1a: edge with Mtb ~4GeV for 100fb-1

SPS2 :(focus points M=300GeV), distribution may reflect

GeV560~

GeV480~

1

2

~~

~~

mm

mm

g

g

1000 fb-1 but cut is not optimized

But cross section is small…. (from the plots in Hisano, Kawagoe, Nojiri PRD68.035007)

Conclusions LHC starts soon ! (2007, I hope!) SUSY is polarized. m(jl) distribution is easy to study. Want more example. Jet charge tagging???? New “full reconstruction” technique. It works even for s

mall statistics. Note: If event contains many neutrinos, the method

cannot be applied. Go back to the end points? How to combine end points and “full reconstructions”

We need more thoughts and works. “Crazy theorists” are especially welcome.

And more .. Interplay between LC andLHC

LHC: gluino and two sbottom masses

Hisano, Kawagoe, Nojiri (for LHC/LC)

For the wino like second –lightest neutralino

If WEAK SUSY parameters are known precisely enough, decay pattern of sbottom may be understood as the function of

Precise SUSY with LHC/LC

LC can change “silver” to “gold” Interaction measurementsChecking universality O(1)% O(10%) for GUT scale scalar masses.

Need more precise estimation of running from GUT to weak scale

Fix low energy parameters for DM, Higgs, B, LFV. Ex. O(1%) thermal relic density