Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics1 Accelerator Based Particle Physics Su Dong Stanford Student Orientation Sep/19/2008

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics2 The Fundamental Questions Are there undiscovered principles of nature: new symmetries, new physical laws ? How can we solve the mystery of dark energy ? Are there extra dimensions of space ? Do all forces become one ? Why are there so many kinds of particles ? What is dark matter ? How can we make it in the laboratory ? What are neutrinos telling us ? How did the universe come to be ? What happened to antimatter ?

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics3 Standard Model Remarkably successful so far, passing many precision tests, but we are a lot of questions: Origin of the wide range of masses (few ev to 170GeV) ? Very different mixing matrices for quarks, charged lepton and neutrinos. Why 3 generations ? The rather large number of free parameters is suggesting we are missing some inner secret, but still not enough clues… => experiments and the Higgs boson…

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics4 PEP-II

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics5 BaBar Physics CP violation in B 0 decays

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics6 BaBar Analysis Opportunities Data taking ended Apr/ M BB events 630M cc events 460M  events Largest sample of Upsilon resonance data (  b discovered from them !) 2-photon, ISR Analysis topics: D mixing D decay Dalitz analysis Dalitz analysis of B decay aimed at CKM angle  measurement Additional rotation project: fast timing R&D. Contact: Prof. David Leith

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics7 LHC

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics8 LHC: The Energy Frontier 7 TeV + 7 TeV PP collisions (a factor of 7 up from present highest energy collider Tevatron) Large cross sections for heavy objects such as top quark, Higgs and possible new particles. First collisions (10 TeV) expected in Fall very challenging environment to pull out the interesting physics (thus the need to collective work of large collaborations).

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics9 Physics Opportunities Higgs particle SuperSymmetry Large extra-dimensions The unexpected… SLAC physics strategy: Initial emphasis on physics signature tools (b-tag,jet/missingEt,  identification) and trigger. Use Standard Model measurements with early data to validate these tools to prepare for searches of new physics beyond Standard Model. Current SLAC physics analyses Top quark decays to  lepton New physics search with b-tag and missing energy Search for SUSY Higgs Search for long lived new particles Close collaboration with SLAC theory group

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics10 Challenge of Detecting Interesting Physics Higgs → ZZ → 2e+2  Pile up background

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics11 First Beam Sep/10/2008 More info:

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics12 SLAC Involvement in ATLAS 2 Faculty 12+ Staff physicists & professionals 1 Panofsky fellow 4 Postdocs 3 Grad students & Tier2 computing center staff Still growth ~5 FTE/year Experimental Involvement Pixel vertex detector and tracking High Level Trigger and DAQ Simulation Tier-2 computing center ATLAS Upgrades and pixel inner most layer replacement

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics13 Students on ATLAS Ideal timing for a thesis on a major new frontier experiment with exciting discovery potential, and opportunity to contribute and experience the commissioning of a complex experiment. In a large collaboration and SLAC as a national lab, there is a deep sea of knowledge on detector, electronics, computing besides physics for you to tap on. Collaborators from all corners of the world. It is swimming in the ocean… After initial courses at Stanford, expected to move to CERN to take on experimental duties and jump into the physics activities, and back to Stanford for thesis writeup in the final year(s). Welcome to talk to the current ATLAS students: –3 rd year students: Bart Butler, David Miller (at CERN) –2 nd year student: Dan Silverstein

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics14 Rotation Projects and Contact Info Rotation projects: Detector performance and calibration studies Physics signature reconstruction studies Trigger performance study and algorithm software Detector simulation improvements Detector upgrade testing and online software Detailed info on for students: Prof. Ariel Schwartzman (resident at CERN) Prof. Su Dong Dr. Charlie Young

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics15 ILC

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics16 Linear Collider Physics & Detector Future linear collider at ~1TeV CM energy with complementary capability to LHC. Precision measurements as a probe for new physics: e.g. does the Higgs decay as expected from SM ? Highly granular detector for precision measurements e.g. resolving Z->jet+jet vs W->jet+jet

Sep/19/2008 Su Dong Stanford Student Orientation: Accelerator based Particle Physics17 a single cell of KPiX 200 μm 500 μm Linear Collider Detector Rotation projects: LC physics simulation Silicon detector design studies Silicon strip detector testing. RPC muon detector tests. KPix readout chip tests. John Jaros Marty Breidenbach