Medium Modifications of Charm and Charmonium in High-Energy Heavy-Ion Collisions

The production of charmonia in heavy-ion collisions is investigated within a kinetic theory framework simultaneously accounting for dissociation and regeneration processes in both quark-gluon plasma (QGP) and hadron-gas phases of the reaction. In-medium modifications of open-charm states (c-quarks, D-mesons) and the survival of J/psi mesons in the QGP are included as inferred from lattice QCD. Pertinent consequences on equilibrium charmonium abundances are evaluated and found to be especially relevant to explain the measured centrality dependence of the psi'/psi ratio at SPS. Predictions for recent In-In experiments, as well as comparisons to current Au-Au data from RHIC, are provided.Comment: 4 Latex pages including 4 eps figures and IOP style files. Talk given at the 17th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2004, Oakland, CA USA, 11-17 Jan 2004. To appear in J. Phys.

Evidence for In-Medium Changes of Four-Quark Condensates

Utilizing the QCD sum rule approach to the behavior of the omega meson in nuclear matter we derive evidence for in-medium changes of particular four-quark condensates from the recent CB-TAPS experiment for the reaction gamma + A -> A' + omega (-> pi0 gamma) with A = Nb and LH2.Comment: Submitted to Phys. Rev. Lett., 4 page

Theory and Phenomenology of Vector Mesons in Medium

Electromagnetic probes promise to be direct messengers of (spectral properties of) hot and dense matter formed in heavy-ion collisions, even at soft momentum transfers essential for characterizing possible phase transitions. We examine how far we have progressed toward this goal by highlighting recent developments, and trying to establish connections between lattice QCD, effective hadronic models and phenomenology of dilepton production.Comment: 8 pages latex incl. 12 ps/eps files; invited plenary talk at Quark Matter 2006 conference, Shanghai (China), Nov. 14-20, 200

Photon production in relativistic nuclear collisions at SPS and RHIC energies

Chiral Lagrangians are used to compute the production rate of photons from the hadronic phase of relativistic nuclear collisions. Special attention is paid to the role of the pseudovector a_1 meson. Calculations that include reactions with strange mesons, hadronic form factors and vector spectral densities consistent with dilepton production, as well as the emission from a quark-gluon plasma and primordial nucleon-nucleon collisions, reproduce the photon spectra measured at the Super Proton Synchrotron (SPS). Predictions for the Relativistic Heavy Ion Collider (RHIC) are made.Comment: Work presented at the 26th annual Montreal-Rochester-Syracuse-Toronto conference (MRST 2004) on high energy physics, Montreal, QC, Canada, 12-14 May 2004. 8 pages, 3 figure

It's complicated: age, gender, and lifetime discrimination against working women - the United States and the U.K. as examples

This article considers the effect on women of a lifetime of discrimination using material from both the U.S. and the U.K. Government reports in both countries make clear that women workers suffer from multiple disadvantages during their working lives, which result in significantly poorer outcomes in old age when compared to men. Indeed, the numbers are stark. In the U.S., for example, the poverty rate of women 65 years old and up is nearly double that of their male counterparts. Older women of color are especially disadvantaged. The situation in the U.K. is comparable. To capture the phenomenon, the article develops a model of Lifetime Disadvantage, which considers the major factors that on average produce unequal outcomes for working women at the end of their careers

A Survey of Factors Affecting Computer Implementation in Rural Northeast Tennessee K-12 Public Schools

The purpose of this study was to examine the variables that are apparently affecting the incorporation of computer technology in Northeast Tennessee rural K-12 public schools. Therefore, the present study investigated the relationship between the independent variables--gender, age, and prior experience, and the dependent variables--knowledge about, attitude toward, and use of computer technology among Northeast Tennessee teachers and principals. This study utilized a survey methodology seeking responses from teachers and administrators in Sullivan, Hawkins, Johnson, Washington, Carter, and Unicoi counties. The findings were based on the return of 208 completed surveys which represented a 52% return rate. Based on the findings of the study the following conclusions were reached: First, the overall level of access to computer hardware and software in individual schools is not adequate if computer technology is to become part of the students\u27 learning. Second, schools are providing little or no teacher training in using computer technology for lesson planning, delivery of instruction, research, or to promote hands-on student learning. Third, teachers and administrators believe that computer technology would be extremely helpful in their work now, and in the near future (5 years from now). Fourth, teachers and administrators believe that computer technology will be almost indispensable in the schools of the near future. Fifth, male and female educators report similar attitudes toward, knowledge about, and use of computer technology. Sixth, educators of different ages report similar attitudes toward and use of computer technology. Educators of different ages, however, do not report similar knowledge of computer technology. Seventh, teachers and principals with different levels of prior education experiences report similar attitudes toward, knowledge about, and use of computer technology. Eighth, in planning future training computer training programs, it is probably not necessary to differentiate groups according to personal attributes such as gender, age, and prior experience. Ninth, the potential for the instructional use of computer technology has not yet been realized. The following recommendations were suggested: (1) there should be enough computer technology for teachers and principals to have unrestricted access, (2) there should be sufficient and adequate computer technology training for teachers and principals offered at the local level, (3) there should be adequate support and time for teachers and principals to learn how to use technology and plan for its use in the school setting, (4) this study should be expanded and replicated to include a larger sample size of educators from all across the state of Tennessee, (5) the relationship between age and knowledge of computer technology should be further investigated, (6) teachers and principals who are proficient in computer technology should serve as role models and peer tutors for those who want to learn how to use computer technology, and (7) district and building administrators should provide computer technology training and planning during the school day

Interpretation of Recent SPS Dilepton Data

We summarize our current theoretical understanding of in-medium properties of the electromagnetic current correlator in view of recent dimuon data from the NA60 experiment in In(158 AGeV)-In collisions at the CERN-SPS. We discuss the sensitivity of the results to space-time evolution models for the hot and dense partonic and hadronic medium created in relativistic heavy-ion collisions and the contributions from different sources to the dilepton-excess spectra.Comment: To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2006) v2: references added, minor typos correcte

The Vector Probe in Heavy-Ion Reactions

We review essential elements in using the $J^P=1^-$ channel as a probe for hot and dense matter as produced in (ultra-) relativistic collisions of heavy nuclei. The uniqueness of the vector channel resides in the fact that it directly couples to photons, both real and virtual (dileptons), enabling the study of thermal radiation and in-medium effects on both light ($\rho, \omega, \phi$) and heavy ($\Psi, \Upsilon$) vector mesons. We emphasize the importance of interrelations between photons and dileptons, and characterize relevant energy/mass regimes through connections to Quark-Gluon-Plasma emission and chiral symmetry restoration. Based on critical analysis of our current understanding of data from fixed-target energies, we identify open key questions to be addressed.Comment: Invited Talk at the Hot Quarks 2004 Workshop, July 18-24, 2004 (Taos Valley, NM, USA), 15 pages latex incl 14 figs and iop style files, to appear in the proceeding

Dileptons in High-Energy Heavy-Ion Collisions

The current status of our understanding of dilepton production in ultrarelativistic heavy-ion collisions is discussed with special emphasis on signals from the (approach towards) chirally restored and deconfined phases. In particular, recent results of the CERN-SPS low-energy runs are compared to model predictions and interpreted. Prospects for RHIC experiments are given.Comment: Invited talk at ICPAQGP, Jaipur, India, Nov. 26-30, 2001; 1 Latex and 9 eps-/ps-files Reoprt No.: SUNY-NTG-02-0