Measurements of Measurements of Chargino/Neutralino Masses at the LHCg

B. Dutta1

Will Flanagan2Will Flanagan2A. Gurrola1

T. Kamon1

3N. Kolev3

A. Krislock1

M. VanDyke1

1Texas A&M University, 2University of Colorado, 3University of Regina NSF-REU

OutlineOutline

Characterization of Focus Point (large M0 heavy squarks small µ more top quarks, etc…)

Characterization of Focus Point (large M0 heavy squarks small µ more top quarks, etc…)

Abram’s talk

Solve for M0, M1/2, A0, tan(β), and µ. Calculate Ω h2

Solve for M0, M1/2, A0, tan(β), and µ. Calculate Ω h2

Neutralino masses with lepton

l i ( l

Calculate Ω h2χ~10

Neutralino masses with lepton

l i ( l

This talk!

Mike’s talk

Calculate Ω h2χ~10

analysis (also reconstructing Z)

Chargino masses Chargino masses

analysis (also reconstructing Z)

Mike s talk coming up next.

Chargino masses

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gwith jet analysis and W reconstruction

Gluino mass and top quark reconstruction

gwith jet analysis and W reconstruction

Gluino mass and top quark reconstruction

gwith jet analysis and W reconstruction

Monte Carlo Event/Detector SimulationW ISAJET d PGS4 t t M t C l d tWe use ISAJET and PGS4 to generate Monte Carlo data.

We then perform ROOT analysis to find observables for M0, M1/2, A0, tan(β), and µ (Abram’s talk).1/2, 0, (β), µ ( )

χ~10χ1

3

Prototypical Decay

Large Top Quark Production

4Invariant dilepton mass!

Background

~g~

-tt

l

µ+ µ-

e+ e- Same flavor!~t

χ~20

l+~l−

l+

χ~10

ν-

e+µ-µ+e-

e+e-, µ+µ-Subtract dilepton signal with e+ µ-

µ+ e-

µ+ µ-

tb

W+

l+

e+µ- µ+e ,g‘OSSF – OSDF’

e+ e-

e+ µ

t-b

W-

ν

l−

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Same flavor and opposite flavor!

t -bν

Dilepton Edges∆m for , and , given by these edges

2 b bl f

χ~20 χ~

30 χ~

10χ~

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2 observables for ‘solving the puzzle’ M1/2, A0, and tan(β)

Invariant Dilepton Masses

χ~20

Dileptons From

to decaysχ~10

χ~30

χ~0Dileptons From

χ10

to decays

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Further Masses…~0 ~0

χ~0l−

l+Z

χ~40 decays to via Z bosons. We can find

dileptons from Z decays with their invariant mass.

χ~20

χ40 l+

χ~20Since we know the mass of Z, we can

reconstructs its momentum by knowing the momentum

χ~20χ~

40

the momentum of the dileptons. Thus we can figure out the to

Dileptons f Z

χ2

χ4

mass difference.

We are also tying this to a study from Z

decaysthis to a study of high momentum Z bosons.

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CharginoWith a similar analysis we can

χ~2+/-u

uW+/-

-

With a similar analysis, we can reconstruct W bosons and their jet decays to probe the chargino mass spectrum χ2 u

χ~20

mass spectrum

With these analyses in combination with -t With these analyses in combination with our top quark reconstruction, we can predict gluino masses (Mikes talk coming up next)!

~g~t

tt

~0 g p )

Thus we will have reconstructed the

χ~20

entire decay chain and be able to solve for M1/2, tan(β), and µ

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Conclusions

We can perform a clean and precise lepton analysis of the neutralino mass spectrumReconstruction of charginos, Ws, tops and gluinos is messy (jets) but very gluinos is messy (jets) but very achievable (Mike’s talk up next!)We can calculate M1/2 tan(β) and µWe can calculate M1/2, tan(β), and µusing observablesWe can then calculate the Dark Matter We can then calculate the Dark Matter relic density using DarkSUSY and compare to cosmological observations

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Acknowledgements

Supported in part by DOE grantDOEd GAANN and NSF REUDOEd GAANN, and NSF REU

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