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Axel Lindner, DESY. An experimental Expedition into a new Particle Habitat at smallest Masses. Cosmology Meets Particle Physics, DESY Theory Workshop, 28 September 2011. The next 40 Minutes …. A collection of open questions Phenomena in astrophysics Understanding today‘s Universe
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Axel Lindner, DESY An experimental Expedition into a new Particle Habitat at smallest Masses Cosmology Meets Particle Physics, DESY Theory Workshop, 28 September 2011
The next 40 Minutes … • A collection of open questions • Phenomena in astrophysics • Understanding today‘s Universe • What theory tells • Weakly Interacting Sub-eVParticles: WISPs • Selection of experiments searching for WISPs • Astrophysics • Laboratory • Present Status of WISP seaches and future experiments • Outlook and summary
Open Questions: the Sun • Do we understand our Sun? • The solar corona heating 16MK corona 5800K http://eo.nso.edu/MrSunspot/solarzoo/coronazoo.html How is energy transferred into the corona? Courtesy of K. Zioutas
Open Questions: the Sun • The Sun • X-ray spectra How can one understand the X-ray emission, especially of the quite sun?Is there a new mechanism transporting energy from the core to the surface? Courtesy of K. Zioutas
Open Questions: white Dwarfs • White dwarfs • Old burned-out stars. • Final stage of 97% of all stars. • Mass < 1.4 Msun • Thermally cooling down to black dwarfs(takes longer than the age of the Universe). • Most simple star one could think of! • Composition • Physics http://physics.uoregon.edu/~jimbrau/astr122/Notes/Chapter20.html http://universe-review.ca/I08-25-whitedwarf.jpg
Open Questions: white Dwarfs • White dwarfs cool too fast! • Observed in individual cases. • Seen in samples. • Is there an unknown energy loss channel at work? • Emission of axions? White dwarfs as physical laboratories: the axion case (J. Isern), 7th Patras Workshop on Axions, WIMPs and WISPs, http://axion-wimp.desy.de
Detection of BSM Physics in WD? http://www.indiana.edu/~geol105/images/gaia_chapter_1/white-dwarf.jpg
Open Questions: Dark Matter Due to their non-thermal production in the universe light axions would constitute cold dark matter.Such axions couple extremely weakly to matter: the “invisible” axion. • Dark matter The axion was not invented to solve the Dark Matter problem! H. Baer, presentation at 5th Patras Workshop on Axions, WIMPs and WISPs, 2009
Open Questions: TeV Propagation M. Meyer, 7th Patras Workshop on Axions, WIMPs and WISPs, 2011 TeV photons should be absorbed by e+e- pair production due to interaction with the extragalactic background light (EBL):TeV + eV→ e+ + e- However, the TeV spectra of distant galaxies do hardly show any absorption.
Open Questions: TeV Propagation M. Meyer, 7th Patras Workshop on Axions, WIMPs and WISPs, 2011 TeV photons should be absorbed by e+e- pair production due to interaction with the extragalactic background light (EBL):TeV + eV→ e+ + e- However, the TeV spectra of distant galaxies do hardly show any absorption. TeV photons may “hide”
Open Questions: TeV Propagation M. Meyer, 7th Patras Workshop on Axions, WIMPs and WISPs, 2011 TeV photons should be absorbed by e+e- pair production due to interaction with the extragalactic background light (EBL):TeV + eV→ e+ + e- However, the TeV spectra of distant galaxies do hardly show any absorption. A new axion-like particle (ALP) could solve this issue.
Open Questions: Dark Energy • Dark energy drives the Universe apart. • Is it real?
Open Questions: Dark Energy • Dark energy drives the Universe apart. • Is it real? http://www.softcom.net/users/greebo/laugh.htm "Shhhh. That's the theoretical physicists' new particle uniform.If you can't see it, you won't be allowed to graduate."
Open Questions: Dark Energy • Dark energy drives the Universe apart. • Is it real? • If yes, it might be attributed to a new kindof scalar field corresponding to very light particles. The cosmological constant problem, S. Weinberg, Rev. Mod. Phys. 61, 1–23 (1989)
Understanding the present Universe • LHC probes the very early universe when it was very small, hot and dense. • Dark energy was totally negligible at those times. • Surprisingly, we understand the early universe from fractions of a second to minute scales better than today’s universe. • Dedicated “low energy” experiments are required to get a clue on Dark Energy. L. Verde, 6th PATRAS Workshop, 2010 LHC
Open Questions: Energy Scales • Neutrinos have masses at the meV scale. • The density of Dark Energyin our Universe is 10−29g/cm3, being equivalent to ρDE (2 meV)4 • Today‘s energy density of the universe is about (meV)4. • Does this hint at BSM physics at the meV scale? • We should strive for dedicated experiments to solve this issue!
Summary on open Questions • Very different phenomena may point at yet unknown particles: • Sun, white dwarfs, TeV transparency, dark matter and dark energy • ν-number excess in CMR data, polarization of light from distant quasars, vanishing electric dipole moment of the neutron, … • None of these observations is really significant yet and / or a real contradiction to Standard Model physics. • However, the number of observations is puzzling! • New experiments (PLANCK, CTA) will improve experimental data, hopefully clarifying the situation. Besides waiting for such new data: • Is there a theoretical scenario combining (most of) the puzzling observations? • How can one search with dedicated experiments for new low mass particles?
The next 40 Minutes … • A collection of open questions • Phenomena in astrophysics • Understanding today‘s Universe • What theory tells • Weakly Interacting Sub-eVParticles: WISPs • Selection of experiments searching for WISPs • Astrophysics • Laboratory • Present Status of WISP seaches and future experiments • Outlook and summary
What Theory tells … . … should not be presented by an experimentalists … … looks like bringing owls to Athens here … So only some very brief remarks! http://www.gutenberg.org/files/20392/20392-h/images/411.png
What Theory tells … A hidden sector of particle physics could exist very well: These particles would be uncharged with respect to electroweak and strong interactions and hence appear to be “dark”. • The unification of forces requires extended gauge structures which led to singlets charged under some new gauge group. Thus GUTs or string theories can‘t avoid a hidden sector.
What Theory tells … A hidden sector of particle physics could exist very well: These particles would be uncharged with respect to electroweak and strong interactions and hence appear to be dark. • The unification of forces requires extended gauge structures which led to singlets charged under some new gauge group. Thus GUTs or string theories can‘t avoid a hidden sector. • Gauge hierarchy problem:how could one understand the huge difference between the electroweak scale of 102 GeV and the Planck scale of 1019 GeV? A hidden sector introducing a dynamical SUSY breaking could take care for this. • There could be complex physics within the hidden sector with new forces and charges.
What Theory tells … Particles from a hidden sector could interact in different manners with Standard Model particles: • By gravitation (dark matter in the universe). • By heavy messengers charged under the Standard Model and the hidden sector. • Standard Model particles could be charged also under the hidden sector. This would result in fifth forces.
A new Particle Habitat? • Probably (some / most of ?) the “open question” phenomena point at physics beyond the Standard Model. • There could be a hidden sector of very Weakly Interacting sub-eV Particles (WISPs): • Axion • Axion-like particles ALPs • Hidden photons • Mini-charged particles • Chameleons • … • Such a new habitat is motivated by theory and observations • How to search for such a new particle habitat at low masses?
The next 40 Minutes … • A collection of open questions • Phenomena in astrophysics • Understanding today‘s Universe • What theory tells • Weakly Interacting Sub-eV Particles: WISPs • Selection of experiments searching for WISPs • Astrophysics • Laboratory • Present Status of WISP seaches and future experiments • Outlook and summary
Seeing the “Invisible”: PrimakoffEffect • Axion and axion-like particles (ALPs):exploit the coupling to photons. • photon + photon ↔ ALPphoton + ALP → photon • photon + (virtual photon) → ALPALP + (virtual photon) → photonA virtual photon can be provided byan electromagnetic field. The Search for Axions, Carosi, van Bibber, Pivovaroff, Contemp. Phys. 49, No. 4, 2008
Seeing “invisible” WISPs • Neutral scalar or pseudoscalar WISPs: exploit the Primakoff effect • Neutral vectorbosons (“hidden sector photons” HP): exploit mixing with “ordinary” photons.
Seeing “invisible” WISPs • Neutral scalar or pseudoscalar WISPs: exploit the Primakoff effect • Neutral vectorbosons (“hidden sector photons” HP): exploit mixing with “ordinary” photons. • Minicharged particles (MCP, about 10-6 e): “loop effects”.
Seeing “invisible” WISPs • Neutral scalar or pseudoscalar WISPs: exploit the Primakoff effect • Neutral vectorbosons (“hidden sector photons” HP): exploit mixing with “ordinary” photons. • Minicharged particles (MCP, about 10-6 e): “loop effects”. Axion-Like Particles, Hidden Photons, MiniCharged Particles
“Invisible” WISPs in Astrophysics • Indirect:WISPs would open up new energy loss channels for hot dense plasmas • stringent limits on WISP characteristics from the lifetime of stars, length of neutrino pulse from SN and cosmic microwave background radiation for example. • Direct: • Search for axionsfrom the sun(CAST at CERN) The Search for Axions, Carosi, van Bibber, Pivovaroff, Contemp. Phys. 49, No. 4, 2008
“Invisible” WISPs in Astrophysics • Indirect:WISPs would open up new energy loss channels for hot dense plasmas • stringent limits on WISP characteristics from the lifetime of stars, length of neutrino pulse from SN and cosmic microwave background radiation for example. • Direct: • Search for hidden photons from the sun(SHIPS in Hamburg) • Search for halo dark matter axions(ADMX in the US) The Search for Axions, Carosi, van Bibber, Pivovaroff, Contemp. Phys. 49, No. 4, 2008
“Invisible” WISPs in Astrophysics • Indirect:WISPs would open up new energy loss channels for hot dense plasmas • stringent limits on WISP characteristics from the lifetime of stars, length of neutrino pulse from SN and cosmic microwave background radiation for example. • Direct: • Search for axionsfrom the sun(CAST at CERN) • Search for halo dark matter axions(ADMX in the US) http://www.phys.washington.edu/groups/admx/home.htm lhttp://cast.web.cern.ch
Okun 1982, Skivie 1983, Ansel‘m 1985, Van Bibber et al. 1987 “Invisible” WISPs in the Laboratory “Light-shining-through-a-wall” (LSW) g g Note: PΦg4 G. Ruoso et al. (BFRT Experiment),Z. Phys. C 56 (1992) 505
q = pγ – pΦl: length of B field Axion Production in a magnetic Field • The production (and re-conversion) of WISPs takes place in a coherent fashion.For ALPs (Φ): With PΦ = PΦ = P: g = (P)1/4 · 2 · / (l·B) / F1/2 Please take note: P(B field) / P(beam dump) = 106·(mm/λabs)·(B/T)2·(L/m)2 (A. Ringwald, J. Redondo, arXiv:1011.3741v1 [hep-ph])
ALPS @ DESY in Hamburg ALPS European XFEL PETRA III-Extension DORIS III OLYMPUS PETRA III ALPS-II In the HERA tunnel? FLASH PETRA III-Extension FLASH II
The ALPS Experiment Any Light Particle Search @ DESY Laser Container HERA Magnet Detektor “Light-shining-through-a-wall” (LSW)
The ALPS Experiment Any Light Particle Search @ DESY • DESY • Max Planck Institute for Gravitational Physics (Albert Einstein Institute), and Institute for Gravitational Physics, Leibniz University Hannover • Laserzentrum Hannover • Hamburger Sternwarte A photon regeneration experiment
The ALPS Experiment • New: realize an optical resonator inside the HERA dipole! Lock by adapting the laser frequency to the distance fluctuations between the mirrors. Lock by adapting the distance between the mirrors to the variations of the laser frequency.
ALPS Results (PLB Vol. 689 (2010), 149, or http://arxiv.org/abs/1004.1313) • Unfortunately, no light is shining through the wall! laser hut HERA dipole detector < 10-31/s 3.5·10211/s
ALPS Results (PLB Vol. 689 (2010), 149, or http://arxiv.org/abs/1004.1313) • ALPS is the most sensitive experiment for WISP searches in the laboratory. pseudoscalar and scalar axion-like particles PLB 689 (2010), 149 hidden sector photons and minicharged particlesFilling a gap remaining from astrophysics and other experiments!
Axion-like Particle Status • Present experiments are hardly sensitive enough to probe forthe open questions discussed before. • An ALP with a coupling around 10-11GeV-1 could be Dark Matter and solve the TeV transparency as well as the white dwarf riddles! preliminary Work in progress by P. Arias, M. Goodsell, J. Jaeckel, J. Redondo and A. Ringwald
Hidden Photon Status • Present experiments are only partly sensitive enough to probe forthe hidden photon dark matter. • Hidden photons with a mixing around 10-9 could be interesting! Work in progress by P. Arias, M. Goodsell, J. Jaeckel, J. Redondo and A. Ringwald preliminary
An Outlook to future Experiments (my arbitrary selection) • Light-shining-through-a-wall: • ALPS-II • New possibilities at synchrotron radiation sources? • Searching for WISPs from the sun: • Axion and axion-like particles, chameleons • Hidden photons • Novel dark matter searches utilizing HERA dipoles for example(work in progress, not covered here).
detector HERA dipole laser hut Prospects for ALPS-II @ DESY • Laser with optical cavity to recycle laser power, switch from 532 nm to 1064 nm, increase effective power from 1 to 150 kW. • Magnet:upgrade to 12+12 straightened HERA dipoles instead of ½+½ used for ALPS-I(LSW with straightened HERA dipoles cannot be surpassed by LSW with LHC dipoles!). • Regeneration Cavity to increase WISP-photon conversions, single photon counter (transition edge sensor?). All set up in a clean environment!
The ALPS-II Potential • Search for“hidden photons”: preliminary
The ALPS-II Potential • Search for axion-like particles: preliminary
LSW at Synchrotron Sources • Light-shining-through-a-wall with X-rays
LSW at Synchrotron Sources • Light-shining-through-a-wall with X-rays • Fluxes of up to 1019 photons per second in dedicated beamlines would allow to probe for Dark Energy chameleons in the laboratory! Work in progress by P. Brax, A.L., K. Zioutas
WISPs from the Sun • New Generation AxionHaloscope (CAST successor) preliminary I. Irastorza, 7th Patras Workshop on Axions, WIMPs and WISPs, 2011
WISPs from the Sun • Solar Hidden Photon Search (Toy SHIPS)Tube will be mounted piggyback on an existing telescopeat the observatory Bergedorf(east of Hamburg). Courtesy of M. Schwarz
WISPs from the Sun • Solar Hidden Photon Search (Toy SHIPS) preliminary Courtesyof J. Redondo