120 likes | 234 Views
Latest news on paraphotons. Alessandro De Angelis Universit à di Udine & INFN Trieste GLAST Meeting, Udine, Jan 03. What is a paraphoton. A (sterile) photon mixing with the ordinary photon H.Georgi, S.Glashow & P.Ginsparg, Nature 306 (1983) 765 B.Holdom, Phys. Lett. B166 (1986) 196
E N D
Latest news on paraphotons Alessandro De Angelis Università di Udine & INFN Trieste GLAST Meeting, Udine, Jan 03
What is a paraphoton • A (sterile) photon mixing with the ordinary photon • H.Georgi, S.Glashow & P.Ginsparg, Nature 306 (1983) 765 • B.Holdom, Phys. Lett. B166 (1986) 196 • S.Coleman and S.Glashow, Phys. Lett. B405 (1997) 249 • S.Glashow, Phys. Lett. B430 (1998) “Our speculation (…) suers from the sin of implausibility but enjoys the virtue of verifiability.”
Why paraphotons? • Appear naturally in models with a “shadow universe” • DM problem • Partly violated symmetries could be restored • Help in evading the GZK cutoff • A new degree of freedom for n oscillations
Why again… recent news • Papers on mirror matter (an idea from Sakharov) • R.Foot and S.Mitra, Mirror matter in the solar system: new evidence for mirror matter from Eros, astro-ph/0211067 • R.Foot, Does mirror matter exist?, hep-ph/0207175 • Revelata veritas ! People from the Ummo planet… http://www.ummo-sciences.org/
Current limits on paraphotons • Mostly from the absence of anomalies in the blackbody radiaton (COBE) • S.K. Lamoreaux et al., Phys. Rev. Lett. 57 (1996) 3125 Dv ~ 10-22 c plus limits on bd at b=1 [P(t) = 1 - b2 sin2 (dwt/2)] • S.Glashow, Phys. Lett. B430 (1998) 54 d < 10-32
Paraphotons & cosmological propagation • Velocity oscillations can satisfy the limits from CBR but yet produce observable effects elsewhere • Sn Ia • The mixing with paraphotons would have consequences on the cosmological propagation of photons • Modulation of light from a redshift z P(z) = 1 - b2sin2 (dwž/2H0)
Paraphotons and Type Ia SNe - I • The photon/paraphoton transition could mimic the distortion in the light spectrum from far Type Ia SuperNovae • A. De Angelis and R. Pain, Mod.Phys.Lett. A17 (2002) 2491 If genuine from L, d < 7 10-34
Paraphotons and Type Ia SNe - II • More constraining limits if no distortions were observed in the spectrum of more distant SNe • Spectral analysis • Same spectrum in V-band wrt B-band at z=0 and z=0.5 (Perlmutter et al. 1999) d < 2 10-34
Paraphotons and high energy g • The term w in P(z) = 1 - b2sin2 (dwž/2H0) improves the sensitivity at high E • The spectral distortions introduced by highly frequency dependent oscillations may however in principle wash out in observations, depending on the experimental energy resolution of the detector; thus this value of dcan’t be taken simply as a limit
Paraphotons and GLAST • If GLAST will not observe distortions in the g-ray spectrum at z~1 in the energy region between 30 MeV and 30 GeV, taking into account an energy resolution DE / E ~10%, will allow to exclude the region between 10-39 and 10-43
Paraphotons & ground detectors • The high-energy gamma data from Mkr 501 at a redshift z~0.034, if interpreted as in agreement with models in a range between 100 GeV and 10 TeV and for an energy resolution DE / E ~100%, allow to exclude the region between 10-41 and 10-44
Perspectives • Different tests (astrophysics) • End points? • Relativistic kinematics? • Different models • Different couplings • Disappearance somewhere else • Extra dimensions?