39 research outputs found
Moduli Spaces for D-branes at the Tip of a Cone
For physicists: We show that the quiver gauge theory derived from a
Calabi-Yau cone via an exceptional collection of line bundles on the base has
the original cone as a component of its classical moduli space. For
mathematicians: We use data from the derived category of sheaves on a Fano
surface to construct a quiver, and show that its moduli space of
representations has a component which is isomorphic to the anticanonical cone
over the surface.Comment: 8 page
Judge Jack B. Weinstein, Tort Litigation, and the Public Good: A Roundtable Discussion to Honor One of Americaâs Great Trial Judges on the Occasion of his 80th Birthday
The Volume of some Non-spherical Horizons and the AdS/CFT Correspondence
We calculate the volumes of a large class of Einstein manifolds, namely
Sasaki-Einstein manifolds which are the bases of Ricci-flat affine cones
described by polynomial embedding relations in C^n. These volumes are important
because they allow us to extend and test the AdS/CFT correspondence. We use
these volumes to extend the central charge calculation of Gubser (1998) to the
generalized conifolds of Gubser, Shatashvili, and Nekrasov (1999). These
volumes also allow one to quantize precisely the D-brane flux of the AdS
supergravity solution. We end by demonstrating a relationship between the
volumes of these Einstein spaces and the number of holomorphic polynomials
(which correspond to chiral primary operators in the field theory dual) on the
corresponding affine cone.Comment: 25 pp, LaTeX, 1 figure, v2: refs adde
Overproduction of cosmic superstrings
We show that the naive application of the Kibble mechanism seriously
underestimates the initial density of cosmic superstrings that can be formed
during the annihilation of D-branes in the early universe, as in models of
brane-antibrane inflation. We study the formation of defects in effective field
theories of the string theory tachyon both analytically, by solving the
equation of motion of the tachyon field near the core of the defect, and
numerically, by evolving the tachyon field on a lattice. We find that defects
generically form with correlation lengths of order M_s^{-1} rather than H^{-1}.
Hence, defects localized in extra dimensions may be formed at the end of
inflation. This implies that brane-antibrane inflation models where inflation
is driven by branes which wrap the compact manifold may have problems with
overclosure by cosmological relics, such as domain walls and monopoles.Comment: 31 pages, 16 figures, JHEP style; References added; Improved
discussion of initial condition
Collisions with Black Holes and Deconfined Plasmas
We use AdS/CFT to investigate i) high energy collisions with balls of
deconfined plasma surrounded by a confining phase and ii) the rapid localized
heating of a deconfined plasma. Both of these processes are dual to collisions
with black holes, where they result in the nucleation of a new "arm" of the
horizon reaching out in the direction of the incident object. We study the
resulting non-equilibrium dynamics in a universal limit of the gravitational
physics which may indicate universal behavior of deconfined plasmas at large
N_c. Process (i) produces "virtual" arms of the plasma ball, while process (ii)
can nucleate surprisingly large bubbles of a higher temperature phase.Comment: 25 pages, 9 figure
Judge Jack B. Weinstein, Tort Litigation, and the Public Good: A Roundtable Discussion to Honor One of America\u27s Great Trial Judges on the Occasion of his 80th Birthday
Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV
We present the first measurement of the inclusive three-jet differential
cross section as a function of the invariant mass of the three jets with the
largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96
TeV. The measurement is made in different rapidity regions and for different
jet transverse momentum requirements and is based on a data set corresponding
to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at
the Fermilab Tevatron Collider. The results are used to test the three-jet
matrix elements in perturbative QCD calculations at next-to-leading order in
the strong coupling constant. The data allow discrimination between
parametrizations of the parton distribution functions of the proton.Comment: 10 pages, 4 figures, 2 tables, submitted to Phys. Lett. B, corrected
chi2 values for NNPD
Heavy quarkonium: progress, puzzles, and opportunities
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 -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. The plethora of newly-found quarkonium-like 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\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. 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.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
Discovery and Fine-Mapping of Glycaemic and Obesity-Related Trait Loci Using High-Density Imputation
Reference panels from the 1000 Genomes (1000G) Project Consortium provide near complete coverage of common and low-frequency genetic variation with minor allele frequency â„0.5% across European ancestry populations. Within the European Network for Genetic and Genomic Epidemiology (ENGAGE) Consortium, we have undertaken the fi
Data from a pre-publication independent replication initiative examining ten moral judgement effects
We present the data from a crowdsourced project seeking to replicate findings in independent laboratories before (rather than after) they are published. In this Pre-Publication Independent Replication (PPIR) initiative, 25 research groups attempted to replicate 10 moral judgment effects from a single laboratory's research pipeline of unpublished findings. The 10 effects were investigated using online/lab surveys containing psychological manipulations (vignettes) followed by questionnaires. Results revealed a mix of reliable, unreliable, and culturally moderated findings. Unlike any previous replication project, this dataset includes the data from not only the replications but also from the original studies, creating a unique corpus that researchers can use to better understand reproducibility and irreproducibility in science