1. 08/27/04 Strategies for the search for prompt muons in the downgoing
atmospheric muon flux with the AMANDA Detector
Raghunath Ganugapati(Newt)
Preliminary Exam
08/27/04

2. Outline Physics Goals of the analysis AMANDA detector
Search strategies

3. The AMANDA Detector 19 strings 677 Optical Modules
Full 19 string version
(AMANDA-II) operational
starting in 2000
200 meters diameter
500 meters in height

4. Cherenkov Radiation
 
The products of a neutrino-ice interaction emit Cherenkov radiation as they travel faster than the speed of light in ice
cosn
v/c, n= refraction index

5. Different Potential Event Origins
Extra Terrestrial Neutrinos
(E-2 spectrum)
Backgrounds
Atmospheric Muons
(E-3.7 spectrum)
Atmosphere Neutrinos from
conventional mode(Pions,Kaons)
Possible Atmospheric neutrinos
from charm (E-2.7 spectrum)
(semi leptonic decays of hadrons containing heavy quarks)

6. Origin of Atmospheric Components
The number of particles starts to increase rapidly as the shower moves downwards in the atmosphere on their way and in each interaction the particles loose energy.
The number of particles reaching the earth depends on the energy and type of the incident cosmic ray and the ground altitude (sea level)

7. Interaction VS Decay mc2 (MeV) ct Ecritical (GeV) П+, П- 140 7.8m 115
K+,K-
494
3.7m
855
(D+,D-)
1870
317µm
3.8*107
Ecritical=(mc2/ct)*h0
h0=6.4Km
Ref:hep-ph/ v3 19 Jan 2001

8. Prompt Muons
Charmed particles decay before interacting .Hence muons from decays of charm (and heavier flavors) are called prompt muon.
The flux of prompt muons differs qualitatively from ordinary muons (conventional pions and kaon decay) in two ways
The Energy spectrum is flatter (E-2.7) VS E-3.7 for conventional muons due to interaction
The angular distribution is isotropic

9. Detection of muonic neutrinos
Occasional Interaction
AMANDA does detect electron and tau neutrinos as well but for purposes of the analysis I will be concerned only with muon neutrinos
Original neutrino and the resulting muon is significantly less than the detector resolution (2 – 3 degrees)

10. Neutrino Fluxes Can we do better with downgoing Muons?
The ZHV-D model of charm neutrinos could not be constrained by looking at the neutrino data for one single year. We shall see towards the end if we could constrain this model of charm production from the stand point of looking at muon data.
AMANDA-II E-2 nm

11. Neutrino Vs Muon Fluxes
The prompt electron and the muon neutrino fluxes and the prompt muon flux are essentially the same at sea level. This result is independent of the charm production model and hence a charm muon limit is a limit on charm neutrinos
Ref:GGV,hep-ph/ v1
10 Sep 2002

12. Uncertainty in Charm Cross Sections
The uncertainty spans three orders of magnitude. This is mainly because of the need to extrapolate accelerator data to very high energies and not much is know about p-p interactions. Note that the crossing between conventional to prompt muon fluxes happens between 40TeV and 3 PeV.
Ref: GGV,hep-ph/ v1
10 Sep 2002

13. Charm Mechanism Vs Pion/Kaon Mechanism
The interaction of a high energy cosmic ray with air nuclei produces a charm meson which takes up most of the energy and momentum of the primary.
Showering effect and the production of accompanying Pions and Kaons is negligible when required to estimate the flux at the surface of the earth.
Ref: Doctoral thesis of
Prof.Varieschi

14. Cherenkov Geometry Given a track hypothesis we can
calculate the expected photon
arrival times from an unscattered
Cherenkov cone.
The time residual is the difference between the actual arrival time and the expected arrival time using a Cherenkov geometry

15. Ice Properties
The scattering coefficient over a range of wave lengths is shown.This plot shows that there are layers of ice with different properties.
The clearest ice has a lower scattering coefficient compared to dusty ice.

16. Why Charm Physics?
The level of contribution to charm to the atmospheric neutrinos is something that would hamper the sensitivity of detectors like AMANDA (IceCube) to neutrinos of extra terrestrial origin.
To study heavy hadron Physics which is not well understood at high energies due to the energies we can go in particle accelerators.