1. Spin-Dependent Wimp Limits from a Bubble Chamber E. Behnke,1 J. I. Collar,2* P. S. Cooper,3 K. Crum,2 M. Crisler,3 M. Hu,3 I. Levine,1 D. Nakazawa,2 H. Nguyen,3 B. Odom,2 E. Ramberg,3 J. Rasmussen,2 N. Riley,2 A. Sonnenschein,3 M. Szydagis,2 R. Tschirhart3* Science 15 February 2008: Vol. 319. no. 5865, pp. 933 - 936

2. Why? Why was this experiment done? Dark matter makes up 70% of the universe. We don’t know what dark matter is. It might be WIMP-proton scattering. Wimp-proton scattering is hard to detect. …………Do WIMPs even exist??

3. What to do? What did this experiment do? Exclude background radiation. Increase detection time to include WIMPs. Improve nuclear-recoil specific detection. Find WIMPs.

4. Spoiler: No WIMPs here.

5. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

6. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

7. http://serenitythruhaiku.files.wordpress.com/2009/02/wimp.jpg Weakly-Interacting Massive Particles Hypothetical super-symmetric partners Not much known (mass, etc) Like Heavy, Slow neutrinos. Interacts with WNF and Gravity AxinoAxino · Chargino · Gaugino · Gluino · Gravitino · Higgsino · Neutralino · SfermionCharginoGauginoGluinoGravitinoHiggsino NeutralinoSfermion

8. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

9. http://maltwood.uvic.ca/physics/Libraries/imagelibrary/29-52low.jpg http://en.wikipedia.org/wiki/Bubble_chamber http://beer.thetazzone.com/images/drinkBeer9.jpg

10. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

11. “deactivate inhomogeneous bubble nucleation centers “ Instead of few milliseconds, ‘indefinite’. - Good for WIMP rate of 1/kg*day worst case scenario: < 1/ton*year Tuned to detect only particles of large stopping power (dE/dx>50keV/um) - slow and big) Just like WIMPs

12. A.High (60C) B.Moderate (30C)- High dE/dx only ( 222Rn a-decay) C.WIMP

13. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

14. *****CF3I*****

15. Outline WIMPs Bubble Chambers Bubble Chamber tweaking  For rate  For background Data Conclusions

18. References Spin-Dependent WIMP Limits from a Bubble Chamber  E. Behnke, J. I. Collar, P. S. Cooper, K. Crum, M. Crisler, M. Hu, I. Levine, D. Nakazawa, H. Nguyen, B. Odom, E. Ramberg, J. Rasmussen, N. Riley, A. Sonnenschein, M. Szydagis, and R. Tschirhart (15 February 2008) Science 319 (5865), 933. Wikiedia.com G. Jungman, M. Kamionkowski, K. Griest, Phys. Rep. 267, 195 (1996). C. Rubbia, Nucl. Phys. B Proc. Suppl. 36, xvii (1994).