To say that this is the best book on the quantum theory of fields is no praise, since to my knowledge it is the only book on this subject But it is a very good and most useful book The original was written in German and appeared in 1942 This is a translation with some minor changes A few remarks have been added, concerning meson theory and nuclear forces, also footnotes referring to modern work in this field, and finally an appendix on the symmetrization of the energy momentum tensor according to Belinfante Quantum Theory of Fields Prof Gregor Wentzel Translated from the German by Charlotte Houtermans and J M Jauch Pp ix + 224, (New York and London: Interscience Publishers, Inc, 1949) 36s

Quantum Theory of Fields

Annals of physics

A golden age for heavy-quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the B-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau-Charm factories, JLab, the ILC, and beyond. The list of newly found conventional states expanded to include h(c)(1P), chi(c2)(2P), B-c(+), and eta(b)(1S). In addition, the unexpected and still-fascinating X(3872) has been joined by more than a dozen other charmonium- and bottomonium-like "XYZ" states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c (c) over bar, b (b) over bar, and b (c) over bar bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrial-strength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

/pdf/heavy-quarkonium-progress-puzzles-and-opportunities-2tru0l8jyp.pdf

Heavy quarkonium: progress, puzzles, and opportunities

https://dspace.library.uu.nl/bitstream/handle/1874/212953/strange_epjc.pdf;sequence=2

The ALICE Collaboration

We use the AdS/CFT correspondence to determine the rate of energy loss of a heavy quark moving through = 4 SU(Nc) supersymmetric Yang-Mills plasma at large 't Hooft coupling. Using the dual description of the quark as a classical string ending on a D7-brane, we use a complementary combination of analytic and numerical techniques to determine the friction coefficient as a function of quark mass. Provided strongly coupled = 4 Yang-Mills plasma is a good model for hot, strongly coupled QCD, our results may be relevant for charm and bottom physics at RHIC.

Energy loss of a heavy quark moving through Script N = 4 supersymmetric Yang-Mills plasma

Thermalization and collective flow of charm (c) and bottom (b) quarks in ultrarelativistic heavy-ion collisions are evaluated based on elastic parton rescattering in an expanding quark-gluon plasma (QGP). We show that resonant interactions in a strongly interacting QGP (sQGP), as well as parton coalescence, can play an essential role in the interpretation of recent data from the BNL Relativistic Heavy-Ion Collider (RHIC), and thus illuminate the nature of the sQGP and its hadronization. Our main assumption, motivated by recent findings in lattice quantum chromodynamics, is the existence of D- and B-meson states in the sQGP, providing resonant cross sections for heavy quarks. Pertinent drag and diffusion coefficients are implemented into a relativistic Langevin simulation to compute transverse-momentum spectra and azimuthal asymmetries (${v}_{2}$) of b- and c-quarks in Au-Au collisions at RHIC. After hadronization into D- and B-mesons using quark coalescence and fragmentation, associated electron-decay spectra and ${v}_{2}$ are compared to recent RHIC data. Our results suggest a reevaluation of radiative and elastic quark energy-loss mechanisms in the sQGP.

/pdf/heavy-quark-probes-of-the-quark-gluon-plasma-and-3fipggkopp.pdf

Heavy-quark probes of the quark-gluon plasma and interpretation of recent data taken at the BNL Relativistic Heavy Ion Collider

Charm- and bottom-quark rescattering in a quark-gluon plasma (QGP) is investigated with the objective of assessing the approach toward thermalization. Employing a Fokker-Planck equation to approximate the collision integral of the Boltzmann equation we augment earlier studies based on perturbative parton cross sections by introducing resonant heavy-light quark interactions. The latter are motivated by recent QCD lattice calculations that indicate the presence of ``hadronic'' states in the QGP. We model these states by colorless (pseudo-) scalar and (axial-) vector D and B mesons within a heavy-quark effective theory framework. We find that the presence of these resonances at moderate QGP temperatures substantially accelerates the kinetic equilibration of c quarks as compared to using perturbative interactions. We also comment on consequences for D-meson observables in ultrarelativistic heavy-ion collisions.

/pdf/thermalization-of-heavy-quarks-in-the-quark-gluon-plasma-4tsukl43st.pdf

Thermalization of heavy quarks in the quark-gluon plasma

Dilepton radiation at the CERN super-proton synchrotron

Employing thermal dilepton rates based on a medium-modified electromagnetic correlation function we show that recent dimuon spectra of the NA60 Collaboration in central In-In collisions at the CERN-SPS can be understood in terms of radiation from a hot and dense hadronic medium. Earlier calculated in-medium rho-meson spectral functions provide an accurate description of the data up to dimuon invariant masses of about M approximately or equal to 0.9 GeV, with good sensitivity to the predicted rho-meson line shape, identifying baryon-induced modifications as the prevalent ones. A reliable evaluation of the contribution enables the study of further medium effects: at masses M>0.9 GeV, 4-pion type annihilation accounts for the experimentally observed excess (possibly augmented by effects of "chiral mixing"), while predictions for thermal emission from in-medium omega and phi mesons may be tested in the future.

Comprehensive interpretation of thermal dileptons measured at the CERN super proton synchrotron.

Cyclotron Institute and Department of Physics&Astronomy,Texas A&M University, College Station, Texas 77843-3366, USA(Dated: August 11, 2011)We update our calculations of thermal-photon production in nuclear collisions at the Relativis-tic Heavy-Ion Collider (RHIC). Speciﬁcally, we address the recent experimental observation of anelliptic ﬂow of direct photons comparable in magnitude to that of pions, which is at variance withexpectations based on quark-gluon plasma (QGP) dominated photon radiation. Our thermal emis-sion rate is based on previous work, i.e., resummed leading-order QGP emission and in-mediumhadronic rates in the conﬁned phase. These rates are nearly degenerate at temperatures close to theexpected QCD-phase change. The rates are convoluted over an improved elliptic-ﬁreball expansionwith transverse- and elliptic-ﬂow ﬁelds quantitatively constrained by empirical light- and strange-hadron spectra. The resulting direct-photon spectra in central Au-Au collisions are characterized byhadron-dominated emission up to transverse momenta of ∼ 2-3 GeV. The associated large ellipticﬂow in the hadronic phase mitigates the discrepancy with the measured photon-v

/pdf/thermal-photons-and-collective-flow-at-energies-available-at-4mfs6uhw9l.pdf

Hendrik van Hees

Papers

Heavy-quark probes of the quark-gluon plasma and interpretation of recent data taken at the BNL Relativistic Heavy Ion Collider

Thermalization of heavy quarks in the quark-gluon plasma

Dilepton radiation at the CERN super-proton synchrotron

Comprehensive interpretation of thermal dileptons measured at the CERN super proton synchrotron.

Thermal photons and collective flow at energies available at the BNL Relativistic Heavy-Ion Collider