The Little Big Bang Prof. Charles F. Maguire (with thanks to Prof. S. Victoria Greene) Vanderbilt University Research Explorers: March 23, 2004

Relativistic Heavy Ion Physics Relativistic – kinetic energy is close to (or greater than) the rest mass energy E=mc2. Heavy – any nucleus; in practice from silicon to gold. Ion – must remove electrons from atom in order to accelerate electromagnetically. 3/23/04 Charles F. Maguire Research Explorers

The Structure of the Atom 3/23/04 Charles F. Maguire Research Explorers

The Strong Force – One of four fundamental forces Gravity: Electricity: The strong nuclear force between the quarks increases as the separation increases – this is very different from gravitational or electric forces which get weaker very fast as you get away from the mass or charge 3/23/04 Charles F. Maguire Research Explorers

Quark-Gluon Plasma If quark-gluon plasma is formed in a RHIC collision, it will last less than 0.00000000000000000000001 seconds. (10-23 s) 3/23/04 Charles F. Maguire Research Explorers

A Familiar Phase Transition 3/23/04 Charles F. Maguire Research Explorers

Evolution of the Universe Too hot for quarks to bind!!! Standard Model (N/P) Physics Quark- Gluon Plasma?? Too hot for nuclei to bind Nuclear/Particle (N/P) Physics Hadron Gas Nucleosynthesis builds nuclei up to He Nuclear Force…Nuclear Physics Universe too hot for electrons to bind E-M…Atomic (Plasma) Physics E/M Plasma Solid Liquid Gas Today’s Cold Universe Gravity…Newtonian/General Relativity 3/23/04 Charles F. Maguire Research Explorers

A Relativistic Heavy Ion Collision 3/23/04 Charles F. Maguire Research Explorers

RHIC - The Relativistic Heavy Ion Collider 3/23/04 Charles F. Maguire Research Explorers

Relativistic Heavy Ion Collider RHIC's two concentric rings are made up of 1,740 superconducting magnets. RHIC is powered by over 1,600 miles of superconducting niobium titanium wire, wrapped around the RHIC magnets. 3/23/04 Charles F. Maguire Research Explorers

Interesting RHIC Facts In 20 years of running, RHIC will use less than one gram of gold (which costs about $30 today) RHIC uses enough helium to fill all the balloons in the Macy's Thanksgiving Day Parades for the next 100 years. To get the helium chilled down, RHIC's refrigerators draw 15 megawatts of electrical power. (One megawatt is enough to power 1,000 homes.) RHIC's two large experiments, STAR and PHENIX, are bigger than houses. PHENIX weighs 3,000 tons and STAR weights 1,200 tons. RHIC costs about $99 million per year to operate 3/23/04 Charles F. Maguire Research Explorers

The PHENIX Detector 3/23/04 Charles F. Maguire Research Explorers

The PHENIX Detector 3/23/04 Charles F. Maguire Research Explorers

PHENIX Central Arms East Carriage Central Magnet West Carriage Ring Imaging Cerenkov Drift Chamber Beam-Beam Counter Central Magnet West Carriage 3/23/04 Charles F. Maguire Research Explorers

Pad Chambers from Vanderbilt 3/23/04 Charles F. Maguire Research Explorers

Au+Au Collision at Center-of-Mass Energy of 200•A GeV 3/23/04 Charles F. Maguire Research Explorers

A collision between two gold nuclei in the PHENIX experiment (200 GeV per nucleon) 3/23/04 Charles F. Maguire Research Explorers

Temperature The temperature inside a RHIC collision can exceed 1,000,000,000,000 degrees above absolute zero (that’s one trillion degrees Kelvin) This is ten thousand times the temperature at the center of our sun. 3/23/04 Charles F. Maguire Research Explorers

How to pick the most head-on collisions 3/23/04 Charles F. Maguire Research Explorers

How to tell if we have a plasma hadrons q leading particle leading particle schematic view of jet production Hard scatterings in nucleon collisions produce jets of particles. In the presence of a quark-gluon plasma, the jets lose much of their energy. “Jet Quenching” Once quenched, the jets could not re-appear since this would violate the 2nd Law of Thermodynamics 3/23/04 Charles F. Maguire Research Explorers

Particle Identification using Time Of Flight Time of Flight array <120ps resolution Tracking system used for momentum reconstruction Resulting spectrum shows Both charge signs e/p/K/p Good signal/background!! 3/23/04 Charles F. Maguire Research Explorers

Have we done it? 3/23/04 Charles F. Maguire Research Explorers

RAA vs. RdA for Identified p0 Initial State Effects Only d+Au Initial + Final State Effects Au+Au d-Au results rule out initial state effects as the explanation for Jet Suppression at high pt 3/23/04 Charles F. Maguire Research Explorers

Recent Press From the July 16, 2003 City Paper From the June 19, 2003 New York Times VU takes on Big Bang By Colleen Creamer, ccreamer@nashvillecitypaper.com July 16, 2003   Vanderbilt scientists believe they have recreated matter that existed 14 billion years ago directly after the Big Bang. The recreation of what is called “quark-gluon plasma” may help scientists better understand fundamental properties of matter and the origins of the universe. The research is nearing the final phases at Brookhaven National Laboratory in Long Island. In mid June, the team at Brookhaven held a national press conference announcing the results of the experiments. “It [the news] had a very big impact. The experimentalists are a cautious bunch, and I am in that camp, too,” said Associate Professor of Physics Victoria Green. Green and Vanderbilt Professor of Physics Charles Maguire are a part of the team of physicists working at the Brookhaven National Laboratory using a $600 million atom smasher called the Relativistic Heavy Ion Collider (RHIC). The RHIC creates micro-explosions by slamming the nuclei of gold atoms together at nearly the speed of light. Green said other scientist in Geneva, Switzerland, claimed they had developed the plasma, but had to shut down before they could get adequate results. Maguire said June’s press conference was to state that the opponents of the lab’s theory and results had been disproved. “Now almost everybody believes that this very interesting state of matter is being produced,” Maguire said. “We are not finally sure until we do another experiment but the theorists are all saying, ‘You’ve done it. It’s just the experimentalists that are holding back and not willing to say it.’” Scientists Report Hottest, Densest Matter Ever Observed By KENNETH CHANG UPTON, N.Y., June 18 — Experiments at the Brookhaven National Laboratory have created the hottest, densest matter ever observed, recreating conditions a fraction of a second after the birth of the universe, scientists announced today. The ultradense matter will help scientists understand the makeup of the universe a few millionths of a second after the Big Bang and will cast light on the fundamental forces that hold atomic matter together. "It is without a doubt the densest matter ever created in the laboratory," said Dr. William A. Zajc, a physics professor at Columbia who is one of the hundreds of scientists worldwide working on the project. About 200 physicists filled an auditorium here on Long Island to listen to the findings. The overflow watched on closed-circuit television in a nearby lounge. "A new fundamental phenomenon has been discovered here," said Dr. Peter Rosen, associate director for high energy and nuclear physics at the Energy Department. But the international teams performing the experiments stopped short of saying they had created a new state of matter in which protons and neutrons, the building blocks of atoms, had dissolved into a soup of smaller particles. Additional measurements are needed to confirm the suspicions, the researchers said. 3/23/04 Charles F. Maguire Research Explorers

Does This Mean We Have found the Quark-Gluon Plasma? Not definitely, but we have definitely found something very interesting. Theorists may find another explanation for these results, there may be another state of matter that we haven’t though of, … We need to make more measurements in order to know what we have. Good scientists are careful people. Watch for an announcement this summer These are exciting times for nuclear physics! 3/23/04 Charles F. Maguire Research Explorers

What makes PHENIX work! 3/23/04 Charles F. Maguire Research Explorers