Novel QCD Phenomenology

I review a number of topics where conventional wisdom in hadron physics has been challenged. For example, hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation. Such "direct" processes can explain the deviations from perturbative QCD predictions in measurements of inclusive hadron cross sections at fixed x_T= 2p_T/\sqrt s, as well as the "baryon anomaly", the anomalously large proton-to-pion ratio seen in high centrality heavy ion collisions. Initial-state and final-state interactions of the struck quark lead to Bjorken-scaling single-spin asymmetries, diffractive deep inelastic scattering, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as nuclear shadowing and antishadowing. The Gribov-Glauber theory predicts that antishadowing of nuclear structure functions is not universal, but instead depends on the flavor quantum numbers of each quark and antiquark, thus explaining the anomalous nuclear dependence measured in deep-inelastic neutrino scattering. One cannot attribute such phenomena to the structure of the hadron or nucleus itself. It is thus important to distinguish "static" structure functions computed from the square of the target light-front wavefunctions, versus "dynamical" structure functions which include the effects of the final-state rescattering of the struck quark. The importance of the J=0 photon-quark QCD contact interaction in deeply virtual Compton scattering is emphasized. The scheme-independent BLM method for setting the renormalization scale is discussed. Eliminating the renormalization scale ambiguity greatly improves the precision of QCD predictions and increases the sensitivity of searches for new physics at the LHC. Other novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates.Comment: Invited talk, presented at the Gribov-80 Memorial Workshop on Quantum Chromodynamics and Beyond, May, 2010, Abdus Salam International Centre for Theoretical Physics. Trieste, Ital

New Perspectives for QCD Physics at the LHC

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such "direct" processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the "baryon anomaly" seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p_T photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p_T at the LHC, as well as a novel mechanism for Higgs and Z^0 production at high x_F. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. The elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will increase the sensitivity of searches for new physics at the LHC. The implications of "in-hadron condensates" for the QCD contribution to the cosmological constant are also discussed.Comment: Invited talk, presented at the 5th Workshop on High P_T Physics at the LHC held at the Instituto de Ciencias Nucleares of the Universidad National Automata de Mexico in Mexico City, September 27-October 1, 201

The Origins, Context and Political Significance of the Mushala Rebellion against the Zambian One-Party State

The article focuses on the origins, context, and political significance of Adamson Mushala's rebellion against the Zambian one-party state. While making no substantial military gains, Mushala succeeded in destabilizing the North-Western Province, the site of his insurgency, and creating an atmosphere of fear and paranoia among local and national leaders of the ruling United National Independence Party (UNIP). The Zambian postcolonial state was threatened by the enduring relevance of such allegiances. Mushala capitalized on the strength of local systems of ethnic affiliation, following in the footsteps of chieftain authorities, who had expressed their rejection of UNIP's national project by leading their people across the barely visible colonial borders separating an enduring Lunda polit

A Systematic All-Orders Method to Eliminate Renormalization-Scale and Scheme Ambiguities in PQCD

We introduce a generalization of the conventional renormalization schemes used in dimensional regularization, which illuminates the renormalization scheme and scale ambiguities of pQCD predictions, exposes the general pattern of nonconformal {\beta_i}-terms, and reveals a special degeneracy of the terms in the perturbative coefficients. It allows us to systematically determine the argument of the running coupling order by order in pQCD in a form which can be readily automatized. The new method satisfies all of the principles of the renormalization group and eliminates an unnecessary source of systematic error.Comment: 5 pages, 1 figure, revised to match the published versio

Systematic Scale-Setting to All Orders: The Principle of Maximum Conformality and Commensurate Scale Relations

We present in detail a new systematic method which can be used to automatically eliminate the renormalization scheme and scale ambiguities in perturbative QCD predictions at all orders. We show that all of the nonconformal \beta-dependent terms in a QCD perturbative series can be readily identified by generalizing the conventional renormalization schemes based on dimensional regularization. We then demonstrate that the nonconformal series of pQCD at any order can be resummed systematically into the scale of the QCD coupling in a unique and unambiguous way due to a special degeneracy of the \beta-terms in the series. The resummation follows from the principal of maximum conformality (PMC) and assigns a unique scale for the running coupling at each perturbative order. The final result is independent of the initial choices of renormalization scheme and scale, in accordance with the principles of the renormalization group, and thus eliminates an unnecessary source of systematic error in physical predictions. We exhibit several examples known to order \alpha_s^4; i.e. i) the electron-positron annihilation into hadrons, ii) the tau-lepton decay to hadrons, iii) the Bjorken and Gross-Llewellyn Smith (GLS) sum rules, and iv) the static quark potential. We show that the final series of the first three cases are all given in terms of the anomalous dimension of the gluon field, in accordance with conformality, and with all non-conformal properties encoded in the running coupling. The final expressions for the Bjorken and GLS sum rules directly lead to the generalized Crewther relations, exposing another relevant feature of conformality. The static quark potential shows that PMC scale setting in the Abelian limit is to all orders consistent with QED scale setting. Finally, we demonstrate that the method applies to any renormalization scheme and [...]Comment: 20 pages; Appendix added. This version matches the published pape

The Renormalization Scale-Setting Problem in QCD

A key problem in making precise perturbative QCD predictions is to set the proper renormalization scale of the running coupling. The conventional scale-setting procedure assigns an arbitrary range and an arbitrary systematic error to fixed-order pQCD predictions. In fact, this {\it ad hoc} procedure gives results which depend on the choice of the renormalization scheme, and it is in conflict with the standard scale-setting procedure used in QED. Predictions for physical results should be independent of the choice of scheme or other theoretical conventions. We review current ideas and points of view on how to deal with the renormalization scale ambiguity and show how to obtain renormalization scheme- and scale- independent estimates. We begin by introducing the renormalization group (RG) equation and an extended version, which expresses the invariance of physical observables under both the renormalization scheme and scale-parameter transformations. The RG equation provides a convenient way for estimating the scheme- and scale- dependence of a physical process. We then discuss self-consistency requirements of the RG equations, such as reflexivity, symmetry, and transitivity, which must be satisfied by a scale-setting method. Four typical scale setting methods suggested in the literature, {\it i.e.,} the Fastest Apparent Convergence (FAC) criterion, the Principle of Minimum Sensitivity (PMS), the Brodsky-Lepage-Mackenzie method (BLM), and the Principle of Maximum Conformality (PMC), are introduced. Basic properties and their applications are discussed. We pay particular attention to the PMC, which satisfies all of the requirements of RG invariance...... [full Abstract is in the paper].Comment: 75 pages, 19 figures. Review article to be published in Prog. Part. Nucl. Phy

Consciousness, Origins

To explain the origin of anything, we must be clear about that which we are explaining. There seem to be two main meanings for the term consciousness. One might be called open in that it equates consciousness with awareness and experience and considers rudimentary sensations to have evolved at a specific point in the evolution of increasing complexity. But certainly the foundation for such sensation is a physical body. It is unclear, however, exactly what the physical requirements are for a “central experiencer” to emerge in the course of evolution. Some suggest that it would require a basic brain, others a central nervous system, and others stipulate only a cellular membrane. The open definition is most often assumed by the so-called hard sciences. The closed meaning of consciousness differentiates between a special sort of experience, i.e., conscious experience, and a special sort of awareness (i.e., self-awareness). This is the approach of psychoanalysis and psychology that accepts the existence of an unconscious mind. It is also the view of most phenomenological philosophers and psychologists (Martin Heidegger, Maurice Merleau-Ponty, Jacques Lacan, etc.). This entry discusses several scientific and philosophical views of consciousness and its origins

Origins

Federal Reserve System - History ; Banks and banking - History ; National Bank Act

Genome-wide mapping reveals single-origin chromosome replication in Leishmania, a eukaryotic microbe

Background DNA replication initiates on defined genome sites, termed origins. Origin usage appears to follow common rules in the eukaryotic organisms examined to date: all chromosomes are replicated from multiple origins, which display variations in firing efficiency and are selected from a larger pool of potential origins. To ask if these features of DNA replication are true of all eukaryotes, we describe genome-wide origin mapping in the parasite Leishmania. Results Origin mapping in Leishmania suggests a striking divergence in origin usage relative to characterized eukaryotes, since each chromosome appears to be replicated from a single origin. By comparing two species of Leishmania, we find evidence that such origin singularity is maintained in the face of chromosome fusion or fission events during evolution. Mapping Leishmania origins suggests that all origins fire with equal efficiency, and that the genomic sites occupied by origins differ from related non-origins sites. Finally, we provide evidence that origin location in Leishmania displays striking conservation with Trypanosoma brucei, despite the latter parasite replicating its chromosomes from multiple, variable strength origins. Conclusions The demonstration of chromosome replication for a single origin in Leishmania, a microbial eukaryote, has implications for the evolution of origin multiplicity and associated controls, and may explain the pervasive aneuploidy that characterizes Leishmania chromosome architecture