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Latest news on paraphotons Alessandro De Angelis Università di Udine & INFN Trieste GLAST Meeting, Udine, Jan 03
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2 / 12 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.”
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3 / 12 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 oscillations
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4 / 12 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/
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5 / 12 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 v ~ 10 -22 c plus limits on b at b=1 [P(t) = 1 - b 2 sin 2 ( t/2)] –S.Glashow, Phys. Lett. B430 (1998) 54 < 10 -32
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6 / 12 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 - b 2 sin 2 ( ž/2H 0 )
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7 / 12 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 , < 7 10 -34
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8 / 12 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) < 2 10 -34
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9 / 12 Paraphotons and high energy The term in P(z) = 1 - b 2 sin 2 ( ž/2H 0 ) 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 can’t be taken simply as a limit
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10 / 12 Paraphotons and GLAST If GLAST will not observe distortions in the -ray spectrum at z~1 in the energy region between 30 MeV and 30 GeV, taking into account an energy resolution E / E ~10%, will allow to exclude the region between 10 -39 and 10 -43
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11 / 12 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 E / E ~100%, allow to exclude the region between 10 -41 and 10 -44
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12 / 12 Perspectives Different tests (astrophysics) –End points? –Relativistic kinematics? Different models –Different couplings –Disappearance somewhere else Extra dimensions?
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