Helmut Satz and the Formative Days of RHICT. Ludlam

June 9, 2011

In the Beginning: Making the Case for RHIC1983 NSAC Long Range Plan for Nuclear Physics

Concepts and ideas that called for a new breed of Nuclear Physics, with High Energy Physics tools.

A time of change, and some turmoil for HEP:QCD was still rather new; J/ψ had recently been discovered, as had jets.

Isabelle had just been killed.

At “Quark Matter ‘83”, at BNL, Alan Bromley spoke of long-standing “artificial barriers that have separated nuclear and particle physicists”.

General skepticism that in such complicated collisions, any real physics could be separated from “nuclear effects”.

At the time, there was scant evidence that high energy collisions with nuclei produced more than just a superposition of single particle interactions…

• Cronin effect (enhanced large pT production in p-A)• EMC effect (quarks are softer in nuclei)• Collective flow (projectile “bounce-off”, “side splash” in A-A)• Cosmic ray effects (JACEE experiment)

Collective Effects in nuclear collisions?

Helmut (and friends) stepped in and led us on the long road to RHIC

T.D. LeeWillisGyulassyBaym

In the 1970’s Helmut had established the renowned High energy theory group at Bielefeld, approaching particle physics with statistical and thermodynamic methods.

In 1985 he joined the BNL Physics Department, and for the next decade he divided his time between BNL, Bielefeld, and CERN.

He spoke eloquently to both the NP and HEP camps here in the U.S., and made many trips across the ocean during the critical period prior to RHIC approval in 1990, speaking with scientists and bureaucrats at all levels with a clarity that made the physics crisp and convincing.

McLerran

Presentation to NSAC, May 1986

Statistical QCD“Energetic nuclear collisions are our only tool to study in the laboratory the condensed state of matter in strong interaction physics.” H.S. QM ‘84 summary

Deconfinement as the Mott transition of QCDDebye screening of a given color charge due to the presence of many other such charges…

From the 1986 presentation to NSAC:Phase transition from a color insulator (hadrons) to a color conductor (QGP).

A Theoretical Basis for Quantitative PredictionsPioneering work with the Bielefeld group on finite temperature lattice calculations

The beginning of a subfield in which advances in theory and supercomputers now give precision results to guide experimental programs and analysis at RHIC and LHC.

Energy density of the quark-gluon system, with Wilson fermions, on an 83 x 3 lattice; Celik, Engels, and Satz, Phy. Lett. 133B, 411 (1983).

Several different types of lattice formulations gave robust indications of deconfinement and chiral symmetry restoration at energy density ≈ 2.5 GeV/fm3.

The Key Role of the AGS Heavy Ion Program First look at high energy HI collisions in lab experiments: Essential input for design of RHIC experiments

First experience for NP community with HEP instrumentation and large collaborations

Critical training ground for a generation of RHIC experimenters (and theorists).

AGS E814

Transverse Energy (GeV)

Soon came HI beams in the AGS and SPS, confirming enhanced energy densities in nuclear collisions…

There remained the question of Signatures – How to detect and probe a phase transition?

Ambiguities due to non-thermal effects, uncertainties in plasma evolution, etc.

Experimental program:Many signatures to be checked against

• theoretical model calculations• behavior in p-p collisions

A Direct Probe of DeconfinementThe seminal 1986 paper of Matsui and Satz introduced heavy quarkonium states as a QGP signal

This paper gave the first suggestion that color screening in a hot plasma should preclude the formation of heavy quarkonium bound states, in a predictable way.

The paper contains the first predictions for experimental observations of heavy quark states at RHIC.

1989 Nuclear Physics Long Range PlanAt the final Working Group meeting in Boulder, Helmut gave the summary presentation of the case for RHIC.

This time, the Long Range Plan report more concretely addressed the science case for RHIC, and put it on a path for construction… “We strongly reaffirm the very high scientific importance of the Relativistic Heavy Ion Collider (RHIC). Since the last LRP, theoretical progress has strengthened the case for the existence of a quark gluon plasma, and recent experiments demonstrate the likelihood that conditions favorable to its formation will be obtained.”

Helmut and his contemporaries had established a consensus that the predicted new phase of strongly interacting matter could be explored decisively in high energy nuclear collisions, based on…

• Rigorous approach to QCD theory and phenomenology• Systematic program of experimental measurements

A substantial community of experimentalists was applying these principles in beam lines at the AGS and SPS.

• Funding for RHIC was approved, and collaborations were forming to design the new collider experiments.

By 2003 the RHIC experiments established the “perfect liquid” of strongly interacting matter: • A rich landscape for further discovery.

The success of RHIC has clearly bridged the cultural divide between Nuclear and High Energy Physics: In scientific discovery, and also in accelerator and detector technology.

Helmut’s giant role at the very beginning was critical for the success of this great scientific adventure!