Introduction to Particle Physics
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Introduction to Introduction to Particle Physics Particle Physics How to compute the Universe?
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Introduction to Particle Physics. How to compute the Universe?. What do we study?. How did we get from here… … to here?. So, how did we get from particles to galaxies?. Brief history of the Universe. Thus, we have to understand what our world is made of…. - PowerPoint PPT Presentation
Transcript of Introduction to Particle Physics
Introduction to Particle PhysicsIntroduction to Particle Physics
How to compute the Universe?
What do we study?What do we study?
How did we get from here… … to here?
So, how So, how diddid we get from we get from particles to galaxies?particles to galaxies?
Brief history of the Universe
Thus, we have to understand Thus, we have to understand what our world is made of…what our world is made of…
What is the world made of?What is the world made of?
Fire Water Earth Air… that is, according to
the Greeks!
Modern understanding: the ``onion’’ pictureModern understanding: the ``onion’’ picture
Let’s see what’s inside!
Nucleus
Modern understanding: the ``onion’’ pictureModern understanding: the ``onion’’ picture
Let’s see what’s inside!
Modern understanding: the ``onion’’ pictureModern understanding: the ``onion’’ picture
Let’s see what’s inside!
Mesons and baryons
Modern understanding: the ``onion’’ pictureModern understanding: the ``onion’’ picture
Let’s see what’s inside!
Quarks and gluons
Modern understanding: the ``onion’’ pictureModern understanding: the ``onion’’ picture
… so the answer depends on the energy scale!
Aside: units used in particle physicsAside: units used in particle physics
Energy: electron-volt: 1 eV = 1.6x10-19 J (energy that an electron gains going through a potential difference of 1 Volt)
E = mc2, so set c=1! natural units
Mass: electron-volt
proton mass mp = 938.27 MeV
Momentum: electron-volt
… … same thing about the interactionssame thing about the interactions
The answer depends on the energy scale….
Unification of forcesUnification of forces
The The Standard ModelStandard Model of Elementary of Elementary Particle PhysicsParticle Physics
``Periodic table’’ of matter Interactions: electromagnetic, weak, strong, (gravity)…
Contains 26 parameters: needs experimental inputneeds experimental input
+ Higgs particle
Open questionsOpen questions
Higgs particle is not (yet) discovered mechanism of electroweak symmetry breaking Standard Model does not have ``enough’’ asymmetry
between particles and antiparticles to create the Universe as we know it
CP-violation and baryonogenesis New Physics beyond the Standard Model?
supersymmetry, strings, extra dimensions…
Example: What is CP(T)?Example: What is CP(T)?
Classical mechanics is invariant under C,P, and T!
Classical Field Theory: E&MClassical Field Theory: E&M
Maxwell’s equations are invariant under C,P, and T!
Why do we want to study CP-violation?Why do we want to study CP-violation?
Baryon (and lepton) number - violating processes to generategenerate asymmetry
Universe that evolves out of thermal equilibrium to keepkeep asymmetry from being washed outbeing washed out Microscopic CP-violation to keepkeep asymmetry from being washed outbeing washed out
Matter-antimatter imbalance in the Universe
A.D. Sakharov
How to observe CP-violation?How to observe CP-violation?I. Intrinsic particle properties
electric dipole moments:
Low energy strong interaction effects might complicate predictions!
II. Transitional particle properties
Low energy strong interaction effects complicate predictions!
Why study B-physics?Why study B-physics?
Possibility to control strong interactions• controllable theoretical expansions
New Physics sensitivity• new physics contributions destroy SM relations
``B-factories’’ are hunting for signs of CP-violation in the decays of B-mesons
Example: CKM unitarity:
VVud ud VVubub** + V + Vcd cd VVcbcb
** + V+ Vtd td VVtbtb
**= 0= 0
Experimental methodsExperimental methods
Experimental methods IIExperimental methods II
Threshold (e+ e-) B-factories (CLEO, BaBar, Belle)
Hadronic (pp) machines (CDF, D0, B-Tev, LHCb) ep-machines (HERA at DESY)
Theoretical predictions can be tested experimentally!
Experimental FacilitiesExperimental Facilities
Cornell University SLAC
Experimental Facilities IIExperimental Facilities II
KEK (Japan)
Experimental Facilities IIIExperimental Facilities III
FermiLab (Batavia, IL)
Research in Particle PhysicsResearch in Particle Physics
TheoryTheory
Alexey Petrov William Rolnick
ExperimentExperiment
Giovanni Bonvichini David Cinabro Robert Harr Paul Karchin Stephen Takach
… as well as postdoctoral research associates and graduate students
Conclusions?Conclusions? What the particle physics is Why we study particles How we study particles
Further questions? Prof. Alexey A Petrov Physics Research, Rm. 260 [email protected]
