1 / 18

What is matter made of?

What is matter made of?. Your basic matter is made of nuclei (protons and neutrons) surrounded by electrons All very small- zillions in dust mote. Particle Physics. E,n,p- what else? Zoo of hundreds of particles Made in collisions Exist for short times, then decay or collide

Download Presentation

What is matter made of?

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. What is matter made of? • Your basic matter is made of nuclei (protons and neutrons) surrounded by electrons • All very small- zillions in dust mote

  2. Particle Physics • E,n,p- what else? • Zoo of hundreds of particles • Made in collisions • Exist for short times, then decay or collide • Cosmic Rays and Accelerators

  3. The Standard Model • 12 particles • Four Forces- strong, weak, E+M, gravity • Antiparticles • Quarks come in 3’s or q-antiq pairs ONLY • Leptons have “conserved type”

  4. Four Forces • Strong - gluons hold quarks together • EM- photons = light • Weak- W and Z- q’s change flavor, leptons and neutrinos • Gravity-???

  5. Neutrinos • 3 types- nu-e, nu-mu, nu-tau • More or less massless (maybe) • only interact rarely and weakly with matter

  6. Neutrino Problem Calculation wrong? No Experiment wrong? No Something happens to neutrinos as they travel! Does nu-e turn into nu-mu? • Can calculate solar neutrino flux • Experiments find about half as much • Same for CR-air nu-mu/nu-e ratio • Several experiments-same answer • ?? Confusion ??

  7. Dark Matter Problem • Astronomers can only identify 20% of the mass in a galaxy • Is the rest neutrinos? Maybe...

  8. Minos • Make (mostly) nu-mu beam at FNAL • measure nu-mu/nu-e ratio there • measure it again in Soudan, MN • compare and see if it changes

  9. Making Neutrino Beams • Fermilab makes a beam of protons • Hits a metal target, makes pions and stuff • Focus pions (u-ubar), point at Soudan • Pions decay to muons and nu-mu • muons hit rock, stop • nu-mus continue under Wisconsin to Soudan

  10. Detectors • Near Detector in IL • Far Detector, aka Minos at Soudan • As similar as possible • Far detector is VERY large (7,000 tons) • neutrinos interact weakly- need lots of stuff

  11. Minos Detector • Iron sheets for mass • Plastic Scintillator to detect particles • Plastic emits light when particle goes through • Light is carried out to photodetectors • Data-> Computers

  12. Minos Data • We see neutrinos interact with nuclei • Remnants splatter • Muons go long ways, make “tails” • Electrons make much shorter events • Count nu-mu/nu-e

  13. Backgrounds • Cosmic Rays- constant shower of muons from CRs • Hide underground • Soudan State Park has a 2341 feet deep hole • we’ve worked there before

  14. Soudan State Park • Iron mine given to state in 1962 • Tours all summer • Maintain lowest level • Historic elevator • Nice people! • Summer is pretty...

  15. Soudan 2 • Previous experiment • Looking for proton decay • sees neutrinos • next door to Minos

  16. Minos Collaboration • 200+ people from 3 continents • UMN, Argonne, Caltech, Indiana, Harvard, Tufts • Oxford, Cambridge, RAL, Sussex, Greece • ~25 grad students

  17. Minos Status • Far Det is done, detects neutrinos • Near Det construction starts in April • First neutrinos in 2005

  18. Silliness • Neutrino Lass!

More Related