1 / 10

Dark Matter Electric and Magnetic Dipole Moments [Phys. Rev. D 70 , 083501 (2004)]

Dark Matter Electric and Magnetic Dipole Moments [Phys. Rev. D 70 , 083501 (2004)]. Michael Doran § * Robert R. Caldwell* Marc Kamionkowski † Andriy Kurylov † Kris Sirgurdson † § ITP Heidelberg, *Dartmouth College, † Caltech. How dark is dark ?. So what’s cold & dark ?.

claudiareed
Download Presentation

Dark Matter Electric and Magnetic Dipole Moments [Phys. Rev. D 70 , 083501 (2004)]

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dark Matter Electric and Magnetic Dipole Moments[Phys. Rev. D 70, 083501 (2004)] Michael Doran§* Robert R. Caldwell* Marc Kamionkowski† Andriy Kurylov† Kris Sirgurdson† §ITP Heidelberg, *Dartmouth College, †Caltech

  2. How dark is dark?

  3. So what’s cold & dark ? • Various astronomical experiments show that energy density of the Universe today is • 5% Baryon (ordinary matter) • 25% Cold dark matter (non-interacting matter) • 70% Dark energy (very strange) • Physical properties of dark matter unknown • Direct detection still elusive • Next generation accelerators may detect cold dark matter • If found, a completely different elementary particle and exciting new possibilities • Nobel prize 

  4. Semi-Simple considerations • For permanent dipole moment, spin must be ¹ 0 • We consider Spin ½ Fermion which must be Dirac • Magnetic bound state does not exist • However, bound state between dipolar dark matter and electrons could exist (Fermi & Teller). Yet, dipole moment needed is ruled out by experiments. • In order to pass BBN constraints, our dark matter Fermion must not be relativistic at BBN, hence (except if Dipole is small)

  5. Dark Matter – Photon Lagrangian Interaction Lagrangian is given by So dark matter may interact with baryons via Gell-Mann (1950)

  6. All constraints put together (sneak preview)

  7. Large Scale Structure

  8. Direct Detection • Total cross section is formally divergent, but this is like Coulomb scattering and comes from small momentum transfers. Screening by electrons renders it finite. • Null searches in Germanium detectors place stringent limit of • But wait: Dark-Matter particle could be stopped / slowed down in the rock above!

  9. All constraints put together

  10. Conclusions • We have performed extensive study of constraints on dark matter dipole from all known state of the art experiments • Cosmological constraint is (almost) comparable to ground based experiments • Dipole Moment may be as large as • Nice example of competitiveness of the biggest experiment ever (the Universe) and ground based observations.

More Related