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					    RICE bounds on
  UHE Neutrino fluxes
   in the GZK Regime
plus bounds on new physics

 Data from 2000 through 2004
 confront models of the world
      (PRELIMINARY)
                  Outline
•   What RICE is
•   What the new data say
•   Calculation of bounds on GZK fluxes
•   Results
•   Calculation of bounds on LSG
•   Results
•   Summary and Conclusions
Radio Cherenkov Detection of Neutrinos
16 co-authors from
Kansas, Delaware,
Canterbury, MIT

16 Radio Receivers
200mX200mX200m
Array Between 100m
and 300m UNDER
THE ICE at the
SOUTH POLE

A great debt owed to
AMANDA
   RICE data collected 2000 - 2004
by the Radio Ice Cherenkov Detector
       current RICE authors:
 Ilya Kravchenko,Dave Seckel,
Jenni Adams, Steve Churchwell, Pauline
Harris, Surujdeo Seunarine, Peter
William, Alice Bean, Dave Besson *, Scott
Graham, Sarah Holt, Shahid Hussain,
Doug McKay, Josh Meyers, John Ralston,
Rainer Schiel, Hanah Swift,
*Contact: dzb@kuhep4.phsx.ku.edu
RICE Searches for UHE Cosmic Neutrino
Hits in Antarctic Ice with Radio Antennas
  •   Coherent Cherenkov Pulses from Showers
  •   Pulses Amplified and Sent to Surface
  •   Trigger on 4 hits above Threshold*
  •   Triggered pulses Read into Oscilloscope, Saved
  •   Pulses are Time labeled - basis to reconstruct hits
  •   Acceptance of Above Summarized in Veff, the
      EFFECTIVE VOLUME


  *Background Fixes Discriminator Threshold
RICE Calibrations and Collateral
         Experiments
• Direct in situ attenuation length and refractive
  index in-ice measurements made by RICERS
• Antenna calibrations, gain calibrations, timing
  calibrations, vertexing tests, … are described in:
• I. Kravchenko et al., Astropart. Phys. 19, (2003)
  15; Flux bounds and a recap of the calibrations
  and testing are presented in I Kravchenko et al.,
  Astropart. Phys. 20, (2003) 195
    Effective Volume Comments
• Landau, Pomeranchuk, Migdal effect (LPM)
  makes a difference only to EM showers
• Radio ray bending costs us effective volume. This
  feature is included here for the first time.
• Separate livetimes must be logged for each threshold
  setting, reflecting varying background conditions.
MC hit distribution with raytracing
Transmitter Location
   Reconstruction


                   True (known)
                   Transmitter
                   Depth
RICE 2000-2004 ------ live-time Vs. discriminator threshold
       Next
  RICE LIMITS ON
COSMOGENIC FLUXES
   Cosmogenic Fluxes, Comments:

We choose a wide range of normalizations and several
different forms of energy dependence to illustrate the
corresponding range of rate expectations.

Each of the cases shown is one out of a span of models
(input parameter choices), that each group presents.
The large is the largest one in the KKSS study, the
medium is the smallest in the PJ study, and the small
is the smallest in the ESS study. There is overlap
among all of the groups.
After ~ 1.5 years livetime,
what does RICE see?

NO NEUTRINO EVENTS
PASS FINAL CUTS -
VERTEX LOCATION AND
CONE FIT.
Rate Calculations and 95% CL Limits
  on Cosmogenic Neutrino Fluxes
 • All neutrino flavors are included
 • EM (electron neutrino only) and hadronic showers
   included, so CC and NC counted
 • Improved Monte Carlos of Veff and offline cut
   efficiencies reduce nominal acceptance compared
   to 2000 and 2003 reports
 • 2 years more data and lower ‘03 and -’04
   backgrounds compensate
 • {(Flux)bound = 3x(TxRate)-1modelx(Flux)model }*

        * @ 95%CL, where T is the livetime.
RICE 2000-2004 ---- SM bound on cosmogenic neutrino flux
Next: more limit calculations




        LOW SCALE GRAVITY:
         (LSG) limits on scale
Low Scale Gravity Cross Sections
• Need X- sections for BH production : with and
  without inelasticity (impact parameter effect)
• Need X-cross sections for KK -graviton exchange
  in eikonal (UNITARY) approximation
• Need shower rates from BH and KK-graviton
  (eikonal) AND from SM interactions for total rate
• All cross sections rise with energy, as does Veff,
  while the fluxes fall.
• Rates rely on X-section x Volume x Flux, and the
  product reveals the most sensitive energy range
  for a given detector.
CROSS SECTIONS PLOTS
     RICE 2000-2004---- ~ 1.5 years live-time
     Event Rates From Cosmogenic Neutrinos


                         LSG, 1 TeV Scale
Standard Model




                          LSG, 2 TeV Scale
RICE 2000-2004
---- bounds on LSG from cosmogenic neutrinos
                  Summary
• RICE has completed a first analysis of all
  data from 2000 thru 2004
• No neutrino candidates survive all cuts
• Preliminary bounds on representative -
     “small, medium and large” - GZK, or
  COSMOGENIC , flux models
• Bounds on Planck mass in 6-d low scale gravity
  models via elastic and BH production.
  Degeneracies confuse the interpretation of data.
   RICE continues
   to determine the
STRONGEST LIMITS
 for the energy range
 above about 1018 eV
               Conclusions
• the LARGEST cosmogenic flux model on the
  verge of 2-sigma EXCLUSION
• the INTERMEDIATE and SMALL FLUX
  models still 101-101.5 below confrontation
• Depending on flux model and on low scale gravity
  model dependence, lower bounds on the Planck
  mass range from 1 to 10 TeV.
• Many Interpretations are possible.
  IT’S STILL EARLY IN THE GAME1
RICE 2000-2004 ---- volume with LPM effect
RICE 2000-2004 ---- volume without LPM effect
RICE---- Volume versus Threshold
RICE 2000-2004 ---- SM bound on cosmosgenic neutrino flux
      CROSS SECTIONS

              1. Black holes without inelasticity




D. W. MCKAY                             UNIVERSITY OF KANSAS
                                    Cross sections continued….


     2. Black   holes with inelasticity




       Where,




D. W. MCKAY                         UNIVERSITY OF KANSAS
                                                Cross sections continued….


              Graviton exchange




                                            n
                                    bc 
                        ( s, b)   
                                   b




D. W. MCKAY                                     UNIVERSITY OF KANSAS
                            Cross sections continued….

        Graviton exchange
        continued…




D. W. MCKAY                 UNIVERSITY OF KANSAS
                         Shower rates continued….



    Showers from BHD




D. W. MCKAY            UNIVERSITY OF KANSAS
                                     Shower rates continued….




  Showers from graviton exchange




D. W. MCKAY                        UNIVERSITY OF KANSAS

				
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posted:9/25/2012
language:English
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