1. Beata Malec University of Silesia XXXIII International Conference of Theoretical Physics MATTER TO THE DEEPEST: Recent Developments in Physics of Fundamental Interactions, Ustroń’09

2. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST2 Outline of the talk  Introductory remarks  Context - dark matter problem,  Astrophysical constraints on exotic physics  White dwarfs in perspective G117-B15A as a tool for astroparticle physics  WD constraints on :  multidimensional ADD model  scalar WIMP-nucleon cross section  Conclusion and perspectives

3. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST3 X-ray emission from clusters Gravitational lensing by galaxies and clusters (giant arcs) Dark Matter in the Universe Pioneers: Oort 1923, Zwicky 1925 Flat rotation curves in galaxies  b = 0.042  m = 0.29 ± 0.04 MODERN COSMOLOGY BBN LSS CMBR

4. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST4 Dark Matter in the Universe

5. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST5 Motivation and ideas  Modern astrophysics is a great success of standard physical theories in understanding stellar structure and evolution  Stars serves as a source of constraints on non standard ideas  Some of these constraints turn out to be more stringent than laboratory ones First idea: weakly interacting particles (axions, Kaluza-Klein gravitons, etc.) produced in hot and dense stellar interior are steaming freely – in effect we have additional cooling channel and modification of evolutional time-scales Second idea: If a star is immersed in a halo of supersymmetric dark matter it can have consequences on the course of its evolution

6. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST6 Three main source of astrophysical constraints: (previously considered mainly in the context of additional cooling channels)  Sun (helioseismology) additional cooling – increase of T c  Globular clusters main observables  Height of RGB tip above HB  Number density of stars on HB  Supernova 1987A  Duration of  pulse  Energy budget In practice

7. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST7  White dwarfs are degenerate stars, consist of C and O, they could also have thin outher He and H layers.  WD history is simple: the only one thing they can do is to cool down.  Luminosity is fairly well described by Mestel cooling law  Some of them are pulsating stars - so called ZZ-Ceti variables  asteroseismology - gives opportunity to record many pulsational modes and to measure them with great accuracy New tool – pulsating White Dwarfs (WD)

8. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST8 From the theory of stellar oscillations it is known that WD can support non radial oscillations excited g-modes have frequencies (proportional to) Brunta-Väisäla frequency for degenerate electron gas at non-zero temperature: A~T 2 so 1/P ~T then inferences  from the rate of period change one can estimate cooling rate  when star is cooling its period increases How it works?

9. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST9 Pulsating White Dwarf G117-B15A  discovered (as variable) in 1976 (McGraw & Robinson)  Global parameters  mass 0.59 M 0  Teff =11 620 K (Bergeron 1995)  log(L/L0) = -2.8 tzn. L=6.18 10 30 erg/s (McCook & Sion 1999)  R = 9.6 10 5 cm  Tc = 1.2 10 7 K Chemical composition: C:O = 20:80(Bradley 1995) C : O = 17 : 83(Salaris et al. 1997) Other names RY LMi WD 0921+352

10. Pulsational properties/features: Ustroń, Sept. 16 2009MATTER TO THE DEEPEST10 excited modes – g-modes– non-radial oscilations 215.2 s271 s304.4 s Kepler et al. 1982 Rate of period change is precisely measured for the mode 215. 2 s (Kepler et al. 2000) (Kepler et al. 2005) Change of the period gives information about cooling rate !

11. Systematic effects (secular): Ustroń, Sept. 16 2009MATTER TO THE DEEPEST11 Proper motion van Altena et al. 1995 residual gravitational contraction – negligibly small core crystalization –DAV stars are too hot proper motion effect (Pajdosz 1995) Theoretical prediction of the Salaris (1997) model Corsico et al. 2001

12. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST12 Excellent agreement between theory and the observed rate of period change -> a source of constraints It restricts possibility of new energy sources or cooling channels In the Mestel law approximation Energetic constraints on exotic sources in G117 – B15A Energetic constraint

13. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST13 World is multidimensional: gravity acts in n+4 dimensions, all other interactions „confined” to 4-dim „brane” One can build low-energy effective theory of K-K gravitons interacting with S.M. fields [Barger et al. 1999, Cassisi et al. 2000] emission rate Observed rate of change of period Theoretical rate of change of period ADD Model

14.  LEP  Ms > 1 TeV/c2  SUN  Ms > 0,3 TeV/c2  Globular Clusters  Ms > 4 TeV/c2  SN1987A  Ms > 30-130TeV/c2  WD G117-B15A  Ms > 8,8 TeV/c2 Ustroń, Sept. 16 2009MATTER TO THE DEEPEST14 Comparison of bounds

15. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST15 Stars are immersed in the Galactic dark halo What are the consequences ?

16. Accretion of dark matter Ustroń, Sept. 16 2009MATTER TO THE DEEPEST16 Capture rate Barometric distribution of WIMPs sets in Majorana particles - -> annihilate Stady state: accretion and annihilation rates are equal Additional luminosity Spergel & Press 1985 Gould 1987

17. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST17 In the supersymmetric model of WIMPs (neutralino) One can obtain the upper bound on nucleon scatering cross section

18. Recapitulation o Pulsating white dwarf G117 – B15A is a nice tool for astroparticle physics: o Long sequence of observational data (fotometric and spectroscopic) o Well calibrated astroseismologically o Pulsational mode 215 s – one of the most stable clocks in nature (the most stable „optical clock”) Ustroń, Sept. 16 2009MATTER TO THE DEEPEST18

19. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST19

20. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST20

21. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST21 additional energy loss channel due to KK-graviton emission relevant process - gravibremsstrahlung in static electric field of ions. e e e e e e e e Gkk

22. Ustroń, Sept. 16 2009MATTER TO THE DEEPEST22 specific mass emissivity for this process calculated by Barger et al. Phys Lett B 1999 the upper 2  limit on P OBS translates into a bound: the final result for the constraint on mass scale M S is: