What are elementary particles, and why should we care? Dhiman Chakraborty (dhiman@nicadd.niu.edu)‏ QuarkNet Masterclass, NIU, 14 March, 2012

QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The fundamental questions What is the world made of? What holds it together? How did it all start? What does the future hold? What/who else is out there? “What is it that breathes fire into the equations and makes a universe for them to describe? Why does the universe go to all the bother of existing?” – Stephen Hawking QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unsolved mysteries Driven by new puzzles in the understanding of our physical world, particle physicists are finding paths to new wonders and startling discoveries. Experiments may even find hidden extra dimensions, mini black holes, and/or evidence of string theory. QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unsolved mysteries QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The small QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The large QuarkNet Masterclass NIU, 14 March 2012 Graphics courtesy: NASA QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Exploring the Universe with Hubble Ultra-Deep Field reveals galaxies forming and evolving Photo courtesy: NASA QuarkNet Masterclass NIU, 14 March 2012

The extremes are connected We want to explain the structure and phenomena at the largest scales (cosmology), in terms of the smallest (particle physics). Particle physicists, in turn, are getting their cues from cosmological observations. The two are inextricably coupled. Fortunately, they are also easier to model precisely than anything in between. Systems in biology, economics, geology etc. are far more complex. Particle astrophysics is a rapidly growing field. 95% of what constitutes the Universe is yet unknown/ unobserved. Some of it must be explained by particle physics. A revolution of unparalleled proportions is around the corner. QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Composition of the Universe Graphics courtesy: NASA QuarkNet Masterclass NIU, 14 March 2012

QuarkNet Masterclass NIU, 14 March 2012

Ways to study structures Cosmology: Look at the object object at all possible wavelengths Particle physics: Shoot all possible probes at the object QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

To probe small distances, we need high energies: E = 2/ , where is the wavelength of probe QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Matter and interactions “Matter”: made of Fermions. Spin-(2n+1)/2 particles that do not share a quantum state. Consequently, their production, annihilation, or decay must be associated with either another fermion or an “anti- fermion”. This results in the conservation of number of matter particles. “Interactions”: mediated by Bosons. Spin-n particles that gladly share a quantum state. Can be radiated, absorbed, or decayed singly. Thus, the number of bosons is not conserved. Bosons can interact among themselves. QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The four forces (carried by bosons)‏ Affects everything, Infinite range, No neutralization Dominant at planetary-to-cosmic scales No quantum description yet. Affects only electrically charged bodies, Infinite range, Bound states are often neutral Prominent at atomic-to-stellar scales Affects all fermions, Very short (sub- nuclear) range, Not a binding force, Only interaction to cause transmutation of matter. Affects only “color”- ed objects (quarks & gluons), Very short (nuclear) range, Strong neutralization Dominant at nuclear scales QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The matter particles (fermions)‏ QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Beyond SM: Grand Unification QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unification of forces Diagram courtesy: H. Murayama QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Unification theories QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Open questions What makes fundamental particles massive? Why do fermions come in multiple “flavor”s? Could it be related to their mass? What can we learn from the neutrinos? Are there undiscovered principles of nature? New symmetries? New physical laws? “Extra” dimensions? Do all forces unify at high energies? What happened to all the antimatter? How can we explain the “Dark Energy”? What constitutes the “Dark Matter”? QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The many connections QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

A timeline of HEP Colliders The LHC is almost certain to make revolutionary discoveries within first 2-3 years of full-scale operation. The ILC/NLC will help us make high- precision measure-ments pin down the details of any new TeV-scale physics. QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Fermilab QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Collider Detectors DØ CDF QuarkNet Masterclass NIU, 14 March 2012 Replace CDF with CMS/ATLAS QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

A top-antitop event QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

A top-antitop event QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The Large Hadron Collider (LHC) at CERN QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

LHC parameters Circumference Collision Energy Injection energy Crossing angle Particles per bunch Number of bunches Dipole field Number of dipole magnets Number of quadrupole magnets Number of corrector magnets Luminosity 26.7 km (16.56 mi)‏ 7+7 TeV 0.45 TeV 300 μrad 1011 2808 8.33 Tesla 1232 about 600 about 7000 1034 cm-2s-1 QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

The ATLAS detector at LHC QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Outlook A large number of particle physics, astrophysics, and cosmology projects – both theoretical and experimental – are underway. They complement each other toward a common goal – to solve the most fundamental mysteries of nature. It is a truly INTERNATIONAL effort. We are living through a revolution in our understanding of the Universe on both the smallest and the largest scales. The next decade or two will usher us into a new era of observation and comprehension. QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty

Feel free to contact the speaker THANK YOU! Feel free to contact the speaker for more information dhiman@nicadd.niu.edu QuarkNet Masterclass NIU, 14 March 2012 Elementary particles & cosmology - Dhiman Chakraborty