The 2008 Annual Fall Meeting of the Division of Nuclear Physics in Oakland, California
By Jim Thomas
The Annual Fall Meeting of the Division of Nuclear Physics of the American Physical Society was held October 23-26, 2008 at the Marriott City Center Hotel in Oakland, California. Three associated half-day workshops were also held on Thursday morning prior to the conference. 700 people attended the meeting including 100 CEU (Conference Experience for Undergraduate) students.
The workshops highlighted the themes of “Nuclear Physics Underground”, “From Quarks to the Cosmos with Petaflops: Large-Scale Computing in Nuclear Physics”, and “Quantifying the Character of the QGP”.
The Underground Workshop gave an overview of the physics opportunities presented by working at underground laboratories. The speakers discussed past, present, and future experiments with an emphasis on double beta decay, dark matter, and neutrino oscillations. Heide Constantini (INFN-Genova) also discussed the benefits of doing low background nuclear astrophysics accelerator experiments in an underground laboratory.
The Computations workshop explored the world of nuclear physics that can be accomplished on a super computer. Super Nova calculations were prominent in the presentations but perhaps surprisingly, new tools are also available to accomplish old tasks. Martin Savage (UW) explored lattice gauge theory but applied these tools to solving the interactions between hadrons and James Vary (Iowa State) presented ab-initio methods to study nuclear structure in the p shell nuclei.
The sQGP workshop explored the latest developments in Relativistic Heavy Ion Physics with the goal of pursuing quantitative predictions and measurements that are possible with new theoretical tools, including higher-dimensional gravity theories (AdS/CFT), as compared to the experimental data. A remarkable picture is emerging whereby the dynamics of a heavy quark can be described by the mathematics of a string in a 5 dimensional gravitational space. Derek Teaney (SUNYSB) discussed the energy loss of a heavy quark in 5 dimensions, while Magdalena Djordjevic (Ohio State) handled the 4 dimensional QCD theory. Denes Molnar (Purdue) used 4D hydrodynamics to show the theoretical influence of a small shear viscosity on heavy ion observables at RHIC; including particle spectra and flow. Bill Zajc (Columbia, and DNP Vice Chair) reviewed the experimental values of the viscosity to entropy ratio (η/s) extracted from particle spectra and flow measurements as well as theoretical calculations from a variety of viewpoints including AdS/CFT. RHIC data is beginning to yield quantitative estimates indicating that η/s is near a quantum mechanical lower bound. Finally, Joern Putschke (Yale) showed that full jet reconstruction can be achieved in AA collisions at RHIC and this should allow a quantitative measure of the energy of the struck parton before additional energy loss in the medium. The preliminary result of these studies is that the fragmentation function for p-p collisions is very similar to the observed fragmentation function for Au+Au collisions. Looking to the future, Paul Sorensen (BNL) showed us what can be done with a low energy scan at RHIC.
The invited sessions at the DNP meeting covered many topics, but an important talk for the RHIC community was given by Jamie Nagle (Colorado) where he reviewed recent progress in heavy ion physics at RHIC for a general audience of Nuclear Physicists. His talk included the spectacular machine developments at RHIC, recent RHIC physics discoveries, as well as a display of the first particles created by the LHC and seen by ALICE. Roy Holt (Argonne) gave a comprehensive review of nucleon structure, highlighting the recent achievements at Jefferson Lab and at RHIC as well as the prospects to precisely determine the gluon spin contribution to the nucleon spin in an upcoming spin run at RHIC. In another invited session entitled “Nucleon Spin Structure and Its Spin-Offs”, Feng Yuan (LBL) focused on QCD dynamics in transverse spin phenomena; while Spin physics and RHIC results from STAR, PHENIX and BRAHMS were covered by Ralph Seidl (RBRC).
There were a number of outstanding mini-symposia that featured a 30 minute invited talk followed by a series of shorter 10 minutes talks. “A 3D View of the Nucleon and its Spin” was a particularly well represented topic that spanned four sessions. The leadoff speakers were Xiangdong Ji (Maryland), Ernst Sichtermann (LBL), Edward Kinney (Colorado), and Gerry Miller (Washington), who discussed theoretical and experimental progress in deep-inelastic lepton-nucleon and polarized p-p scattering.
Miklos Gyulassy (Columbia) was the lead-off speaker for a session on the properties of the ridge in ultra-relativistic heavy ion collisions. He showed, among other things, that AdS/CFT does not produce a Mach Cone with features that are comparable to what is seen in the data. While Lanny Ray (Texas) and Duncan Prindle (Washington) gave contributed talks that demonstrated an abrupt transition and appearance of the ridge, as a function of centrality, in Au-Au and Cu-Cu collisions.
The contributed talks (10 minutes each) ran in eight simultaneous parallel sessions for 2 and a half days and were extremely well attended. Some of the highlights from these contributed talks included an interesting result by Shengli Huang (Vanderbilt) which suggests a breakdown of constituent quark scaling at high transverse momentum using flow (v2) as the observable. Len Eun (Penn State) presented remarkably large single transverse spin asymmetries in the production of eta mesons at forward directions.
Overall, the conference was well attended and a large number of excellent talks were given in all areas of Nuclear Physics. We also enjoyed four days of warm and sunny weather which made the experience even better.
The scientific program for the meeting can be found on the conference web site: http://www.lbl.gov/dnp08
Ernst Sichtermann, Richard Seto, and Flemming Videbaek contributed to this report.