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

apetrov@physics.wayne.edu