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

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??

What to do?What did this experiment do?

Exclude background radiation.

Increase detection time to include WIMPs.

Improve nuclear-recoil specific detection.

Find WIMPs.

Spoiler:

No WIMPs here.

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

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

Axino · Chargino · Gaugino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

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

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

“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

A. High (60C)

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

C.WIMP

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

*****CF3I*****

Outline

WIMPs Bubble Chambers Bubble Chamber tweaking

For rateFor background

Data Conclusions

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).