Testing Lorentz Invariance with UHECR Spectrum

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Testing Lorentz Invariance with UHECR Spectrum

• Li Ye
• IHEP, CAS, Sep. 26, 2008

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Outline

• Lorentz Invariant Violation and UHECR spectrum
• Theoretical UHECR spectrum
• UHECR spectrum modified by LIV
• Constraints on LIV parameter

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Lorentz Invariant Violation(LIV)
Sidney Coleman, Sheldon L. Glashow, Phys.Rev.
D59 (1999) 116008
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UHECR spectrum and GZK cutoff
E(eV)

• Source
• galactic gt
• extragalactic

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GZK cutoff ? Hires VS. AGASA
If AGASA, Lorentz invariant is violated?
If Hires, the energy calibration of AGASA is in
doubt?
E, eV
F.W. Stecker, S.T. Scully, Astropart.Phys. 23
(2005) 203-209
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Newest Experimental results
E, eV
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Theoretical UHECR Spectrum

• Sources
• Homogeneous in space
• Power law spectrum with index

V.Berezinsky, A.Z.Gazizov, S.I.Grigorieva
Phys.Rev. D74 (2006) 043005
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Influence of LIV on spectrum

• The modified inelasticity
• of interactions

Energy loss of proton interactions with CMB
UHECR Spectrum
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Spectrum modified by LIV
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Cofidence regions
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Conclusion

• UHECR spectrum will be modified by LIV
• Observational data can set constraint on LIV. The
  result from Hires is
• Experimental data with higher precision can give
  better test on Lorentz Invariant

This talk is updated on Nov.30th.