1. Propagation of Supersymmetric Charged Slepton at High Energies
Shufang Su • U. of Arizona
M.H. Reno, I. Sarcevic and S. Su
hep-ph/

2. Motivation Neutrino telescopes have great potential-
Neutrino telescopes have great potential
to probe new physics beyond SM 
earth  ~
Gravitino LSP
Stau NLSP  
earth
Msl=250 GeV
Mwino=250 GeV
Albuquerque, Chacko
and Burdman (2003)  N  l ~ q 
Larger production rate
smaller production rate
 = 2.197£ 10-6 sec
c=659 meter
Larger effective detector volumn
S. Su
stau propagation

3. stau energy loss -
Discovery potential for neutrino telescope depends on the stau lifetime and range
Crucial to determine the energy loss of the high energy stau as it traverse the earth
S. Su
stau propagation

4. Average energy loss of a particle traversing distance X
stau energy loss -
Average energy loss of a particle traversing distance X
ionization energy loss
Constant: =2 £ 10-3 cm2/g
radiative energy loss
m,  , more later …
energy
When  E ¿ ,
i.e. E ¿ 4 £ 105 GeV £ (msl/150 GeV)
Stau range determined by
ionization energy loss  or lifetime c
 c = E / ()
S. Su
stau propagation

5. radiative energy loss: -
photonuclear
bremsstrahlung
pair production
S. Su
stau propagation

6. radiative energy loss: -
Stau
/ 1/m
Stau: mass dependence
muon
/ 1/m2
S. Su
stau propagation

7. stau range: X(E, E0)  E À   E ¿  m=250 GeV lifetime m=250 GeV-
m=250 GeV
lifetime
m=250 GeV
m=150 GeV
E0=106 GeV
lifetime
m=250 GeV
 E À 
m=150 GeV
m=150 GeV
 E ¿ 
E0=103 GeV
S. Su
stau propagation

8. Comparison ? Xus / XABC In Albuquerque, Chacko and Burdman (2003)-
In Albuquerque, Chacko and Burdman (2003)
Rescale from :
 = 0.8 £ 10-6 cm2/g 
stau=9.5 £ 10-9 (150 GeV/mstau) cm2/g
No energy dependence
Xus / XABC ?
Improve the potential of neutrino
telescopes for detecting metastable stau
S. Su
stau propagation

9. Conclusion Stau radiative energy loss  is dominated by-
Stau radiative energy loss  is dominated by
photo-nuclear and pair production
Photonuclear and pair: / 1/m
Bremsstrahlung: / 1/m2
Low energy ( E ¿ ), stau range is determined by ionization energy loss or stau lifetime, X / E
High energy ( E À ), stau range is determined by radiative energy loss, X / log (E)
Previous estimation (scale stau) underestimate stau range by about a factor of two
S. Su
stau propagation