Particle Physics Past;Particle Physics Future

Fred GilmanT.D.’s 80th

September 29, 2006

Particle Physics Past (1960)• In the summer of 1960, I was an

undergraduate summer student in the bubble chamber group at Brookhaven National laboratory.

• Particle physics was in its infancy. It was known that parity was violated; we saw the inklings of a zoo of particles to follow and a crazy array of new phenomena. We were near the beginning of a revolution in our understanding of the universe. Ahead of us were CP violation, six quarks, six leptons, …

• A seminar by Mel Schwartz – 3 leptons or 4?

Particle Physics Past (1963):Cronin-Fitch Proposal

Particle Physics Past (1963):Cronin-Fitch Proposal (con’t)

Particle Physics Past (1963):Cronin-Fitch: Answer from the Lab

Particle Physics Past (1963):Cronin-Fitch: Experiment

Particle Physics Past (1974):Ko Matter-Antimatter Oscillations

scale: thousands of ps

Particle Physics Past (1990s):The KTeV Experiment

Particle Physics Past:Bd Matter-Antimatter Oscillations

scale: tens of ps

Particle Physics Past (1 week old): Bs Matter-Antimatter Oscillations

scale: tenths of ps

Quark Mixing and CP Violation• All this, and more, fits into our understanding of the weak

interactions of 6 quarks − a triumph of the Standard Model.• From the measured rates of Bd mixing, Bs mixing, and b → u,

we can calculate the amount of CP violation exhibited in the neutral K meson system by Fitch and Cronin.

• The present error bar on our calculation is about 15%, almost entirely coming from theory. This small blot on our reputation will finally be erased in the near future through improvements in calculations underway using lattice gauge theory.

• We think that we understand CP violation as seen up to now in our earthly laboratories. But where does the CP violation necessary to explain the amount of matter, and very little antimatter, in the universe around us come from?

That’s Not All We Don’t UnderstandDark Matter

Particle Physics TodayThe Quantum Universe 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 the 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 the antimatter?

Particle Physics Future:Planning a US Program

• Planning by the HEP community: HEPAP subpanels, most recently the Bagger-BarishSubpanel, The Way to Discovery: Particle Physics in the 21st Century in 2002.

• By the National Academies: the EPP2010 Committee, Harold Shapiro (chair), Revealing the Hidden Nature of Space and Time in 2006.

• Within an international context provided by the Global Science Forum Working Group on High Energy Physics report in 2003.

Particle Physics Future:EPP2010 Ordered Priorities

• Exploit the opportunities offered by the LHC• Plan and initiate a comprehensive program to participate in

the global effort to complete the necessary R&D to design and plan an international linear collider

• Do what is necessary to mount an internationally compelling bid to build the international linear collider on U.S. soil

• Seize the opportunities at the intersection of particle physics,astrophysics, and cosmology by coordinating and expanding domestic efforts.

• Pursue an internationally coordinated, staged program in the physics of neutrinos and proton decay.

• Pursue precision probes of physics beyond the Standard Model using available resources as a guide to overall level of effort while maintaining diversity.

Particle Physics Future:Priority 1 − ATLAS at the LHC

Webcam View 060926, 14:30:01

Particle Physics Future:Priority 1 − CMS at the LHC

Particle Physics Future: Cosmological Scope

• 95% of the universe is made of “stuff” unlike the matter around us or makes up the stars and planets. Unlike in previous decades where new particles and fields were found at accelerators, the evidence for dark matter and dark energy came from astrophysics.

• The particles that make up dark matter have properties that suggest they, and their relatives(?), carrying a new quantum number(?), will be produced at TeV energies – the Terascale.

• To understand dark matter, we need to create it in the laboratory and study it with the LHC and the ILC. We would be compelled to explore the Terascale at colliders for this reason alone.

Particle Physics Future:International Scope

• For multibillion dollar projects, not only the cost, but requirements for massive technical and scientific participation have driven an international scope.

• Long-term political support from international bodies is important; treaties reduce risk.

• Planning with our international partners is moving to sub-billion dollar projects. EPP2010: “We need to put greater emphasis on strategic international partnerships.”

International ScopeGSF Science Ministers 2004

High-energy physics

18. Ministers acknowledged the importance of ensuring the long-term vitality of high-energy physics. They noted the worldwide consensus of the scientific community, which has chosen an electron-positron linear collider as the next accelerator-based facility to complement and expand on the discoveries that are likely to emerge from the Large Hadron Collider currently being built at CERN. They agreed that the planning and implementation of such a large, multi-year project should be carried out on a global basis, and should involve consultations among not just scientists, but also representatives of science funding agencies from interested countries. Accordingly, Ministers endorsed the statement prepared by the OECD Global Science Forum Consultative Group on High-Energy Physics (Annex 2).

International ScopeAn Example − US-China Cooperation• The original agreement on cooperation, signed by

Deng and Carter in 1979, led to many exchanges of people, reviews, conferences.

• Annual meetings of the joint PRC-US committee plan for the next year of exchanges, plus extraordinary meetings with government officials in Beijing, in particular, with Wen Jiabao (as member of the CCP Central Secretariat, Vice Premier, and Premier) and Zhu Rongji (as Premier) led to major decisions.

An Example − US-China Cooperation 2Peoples Daily, November 15, 1997

Beijing, November 14. Wen Jiabao, Member of the CCP Political Bureau andCentral Secretariat Meets with American Scientists.

Today Wen Jiabao, member of the CCP Political Bureau and Central Secretariat, met with Nobel Prize winner and U.S. Columbia University Professor T. D. Lee and the three Senior Advisors to IHEP, CAS, the former Director of the Stanford Linear Accelerator Center Professor Panofsky, Professor Tigner of Cornell University and Professor Gilman of Carnegie Mellon University.

Wen Jiabao greatly appreciates T. D. Lee and the three high energy physicists contribution in promoting the collaboration in high energy physics between the U.S. and China. He highly values the contribution of the four for promoting the collaboration in high energy physics between the U.S. and China, for promoting the BEPC, and for training talent people in high energy physics. WenJiabao said the building of the BEPC pushed the development pace of Chinese science and attention to this work. The Chinese Academy of Sciences should further the leadership and management for the upgrade and operation of the BEPC. T. D. Lee and the three other consultants were invited by the Chinese Academy of Sciences to come over to China to visit. They carefully investigated the operation and the upgrading of the BEPC.

An Example − US-China Cooperation 3

• These meetings have enhanced construction of BEPC, operation of the IHEP, and approval of the tau-charm factory, and the BEPC II.

• We are moving to a new stage of cooperation as the dynamic changes and China increasingly builds next generation facilities and experiments in which US scientists participate.

Particle Physics Future:Science Scope

• Support of particle physics nationally (and elsewhere in the world) is seen in a broader context of funding for the physical sciences.

• We may well be seeing the beginning of real increases in funding the physical sciences.

• The fleet of science (and technology) should have leading, flagship projects when setting sail, but a flagship leaving port without the fleet is very precarious.

Particle Physics Future:Conclusion

• We are in revolutionary times in particle physics −answering some of our deepest questions is within our reach.

• For the US program, the next few years are critical. There are big risks and even bigger rewards. Later is increasingly tougher.

• We are inside a national picture for funding of the physical sciences and seeking economic competitiveness, while planning and carrying out our program with international partners.