Experimenting with Quarks Prof. Richard Jones University of Connecticut, Storrs Science Symposium, Darien High School, May 28, 2008

Science Symposium, Darien High School, May 29, Ordinary matter  cup of coffee  atoms  electrons + nuclei  neutrons + protons  quarks Elementary particles: electrons quarks neutron proton

Science Symposium, Darien High School, May 29, What makes things stick? Opposite charges attract What about these guys? electrons (-) nucleus (+) protons (+) neutrons (0) !! The strong nuclear force nuclear glue The electromagnetic force

Science Symposium, Darien High School, May 29, Can we actually “see” elementary particles? not exactly…

Science Symposium, Darien High School, May 29, Thomas Jefferson National Accelerator racetrack accelerator accelerates electrons to 6 GeV upgrading to 12 GeV experiments

Science Symposium, Darien High School, May 29, Why are quarks difficult to see? How were electrons first seen? make a glass vacuum tube apply force using electric potential of several kV electrons rip free from atoms electric current flows The world’s first particle accelerator

Science Symposium, Darien High School, May 29, What makes seeing quarks interesting? J.J Thompson: "Could anything at first sight seem more impractical than a body which is so small that its mass is an insignificant fraction of the mass of an atom of hydrogen?" Can we try it again with quarks? people tried, no success

Science Symposium, Darien High School, May 29, % of the mass of ordinary matter is locked up in particles composed of quarks mass is energy – E = mc 2 all of this energy is stored safely in the nuclei of the ordinary elements can additional energy be pumped in and converted to more mass? What makes seeing quarks interesting? new exotic particles

Science Symposium, Darien High School, May 29, Two quarks on a string So what happens when you pull on a quark inside a proton? N. Isgur, 1988: What happens if you stretch the string, and then pluck it? theoretical simulation courtesy of D. Leinweber 1.the quark begins to move 2.a glue string forms 3.the string stretches 4.the quark slows down 5.the quark snaps back – denied!

Science Symposium, Darien High School, May 29, The GlueX experiment

Science Symposium, Darien High School, May 29, The GlueX experiment Time line for experiment 1997 – first meeting 1999 – initial proposal 2002 – mature proposal 2003 – project adopted by DOE 2006 – mature design 2009 – construction starts 2014 – commissioning 2017 – first results! UConn responsibility

Science Symposium, Darien High School, May 29, Prototyping detectors

Science Symposium, Darien High School, May 29, Prototyping detectors

Science Symposium, Darien High School, May 29, Diamond radiators large area, highly parallel X-ray beam from C-line monochromator   X-ray CCD camera diamond crystal Assessment with X-rays at the CHESS light source 10  r FWHM

Science Symposium, Darien High School, May 29, Active Collimator active device primary collimator (missing) incident photon beam beam test in Hall B in April cm beam tungsten plates tungsten pins

Science Symposium, Darien High School, May 29, x (mm) y (mm) current asymmetry vs. beam offset 20% 40% 60% Active Collimator inner cable outer Monte Carlo simulation test beam data (raw)

Science Symposium, Darien High School, May 29, Photon tagger Tagger “microscope” scintillating fibers read out with SiPM’s

Science Symposium, Darien High School, May 29, Photon tagger “Silicon PMT” (multi-pixel APD in Geiger mode) 2mm  8 MeV tagging channel width  200 ps time resolution  4 MHz/fiber

Science Symposium, Darien High School, May 29, New Beam Line radiator collimator

Science Symposium, Darien High School, May 29, Construction of Hall D google earth viewer

Science Symposium, Darien High School, May 29, The Competition China – Beijing Electron-Positron Collider BES experiment Europe – FAIR Antiproton Accelerator PANDA experiment CERN – LHC and fixed-target experiments COMPASS experiment Japan – JPARC Proton Accelerator several multi-GeV beam lines proposals in preparation

Science Symposium, Darien High School, May 29, Status and Outlook Funding is approved for GlueX Construction should begin soon Lots of opportunities for students at all levels Exciting discoveries await!