651025
D-branes on Calabi-Yau spaces and their mirrors
We study the boundary states of D-branes wrapped around supersymmetric cycles in a general Calabi-Yau manifold. In particular, we show how the geometric data on the cycles are encoded in the boundary states. As an application, we analyze how the mirror symmetry transforms D-branes, and we verify that it is consistent with the conjectured periodicity and the monodromy of the Ramond-Ramond field configuration on a Calabi-Yau manifold. This also enables us to study open string worldsheet instanton corrections and relate them to closed string instanton counting. The cases when the mirror symmetry is realized as T-duality are also discussed.
5633727
Anomalies, Branes, and Currents
Abstract When a D-brane wraps around a cycle of a curved manifold, the twisting of its normal bundle can induce chiral asymmetry in its world-volume theory. We obtain the general form of the resulting anomalies for D-branes and their intersections. They are not cancelled among themselves, and the standard inflow mechanism does not apply at first sight because of their apparent lack of factorizability and the apparent vanishing of the corresponding inflow. We show, however, that after taking into consideration the effects of the non-trivial topology of the normal bundles, the anomalies can be transformed into factorized forms and precisely cancelled by finite inflow from the Chern-Simons actions for the D-branes as long as the latter are well defined. We then consider examples in type 11 compactifications where the twisting of the normal bundles occurs and calculate the changes in the induced Ramond-Ramond charges on the D-branes.
10041169
Conformal invariance on orbifolds and excitations of singularity
We study conformal field theory on two-dimensional orbifolds and show this to be an effective way to analyze physical effects of geometric singularities with angular deficits. They are closely related to boundaries and cross caps. Representative classes of singularities can be described exactly using generalizations of boundary states. From this we compute correlation functions and derive the spectra of excitations localized at the singularities.
43434280
Matrix Description of Intersecting M5 Branes
Novel 3+1 dimensional N = 2 superconformal field theories (with tensionless BPS string solitons) are believed to arise when two sets of M5 branes intersect over a 3+1 dimensional hyperplane. We derive a DLCQ description of these theories as supersymmetric quantum mechanics on the Higgs branch of suitable 4d N = 1 supersymmetric gauge theories. Our formulation allows us to determine the scaling dimensions of certain chiral primary operators in the conformal field theories. We also discuss general criteria for quantum mechanical DLCQ descriptions of supersymmetric field theories (and the resulting multiplicities and scaling dimensions of chiral primary operators).
17461222
The principle of least action and the geometric basis of D-branes
We analyze thoroughly the boundary conditions allowed in classical non-linear sigma models and derive from first principle the corresponding geometric objects, i.e. D-branes. In addition to giving classical D-branes an intrinsic and geometric foundation, D-branes in nontrivial H flux and D-branes embedded within D-branes are precisely defined. A well known topological condition on D-branes is replaced.
15577760
From boundaries to conditions over superspace
N = 1 and 2 superconformal boundary conditions are shown to be the consequence of a ``boundary'' on the worldsheet superspace with positive codimension in the anticommuting subspace. In addition to the well-known boundary conditions, I also find two new infinite series of N = 2 boundary states. Their free field realizations are given. A self-contained development of 2d superspace leads to new perspectives on this subject.
118498165
Prediction of Underground Argon Content for Dark Matter Experiments
In this paper, we demonstrate the use of physical models to evaluate the production of $^{39}\mathrm{Ar}$ and $^{40}\mathrm{Ar}$ underground. Considering both cosmogenic $^{39}\mathrm{Ar}$ production and radiogenic $^{40}\mathrm{Ar}$ production in situ and from external sources, we can derive the ratio of $^{39}\mathrm{Ar}$ to $^{40}\mathrm{Ar}$ in underground sources. We show for the first time that the $^{39}\mathrm{Ar}$ production underground is dominated by stopping negative muon capture on $^{39}\mathrm{K}$ and ($\ensuremath{\alpha},n)$ induced subsequent $^{39}\mathrm{K}$($n$,$p$)$^{39}\mathrm{Ar}$ reactions. The production of $^{39}\mathrm{Ar}$ is shown as a function of depth. We demonstrate that argon depleted in $^{39}\mathrm{Ar}$ can be obtained only if the depth of the underground resources is greater than $500$ m.w.e. below the surface. Stopping negative muon capture on $^{39}\mathrm{K}$ dominates over radiogenic production at depths of less than $2000$ m.w.e., and that production by muon-induced neutrons is subdominant at any depth. The depletion factor depends strongly on both radioactivity level and potassium content in the rock. We measure the radioactivity concentration and potassium concentration in the rock for a potential site of an underground argon source in South Dakota. Depending on the probability of $^{39}\mathrm{Ar}$ and $^{40}\mathrm{Ar}$ produced underground being dissolved in the water, the upper limit of the concentration of $^{39}\mathrm{Ar}$ in the underground water at this site is estimated to be in a range of a factor of $1.6$ to $155$ less than the $^{39}\mathrm{Ar}$ concentration in the atmosphere. The calculation tools presented in this paper are also critical to the dating method with $^{39}\mathrm{Ar}$.
56119429
Centrality dependence of particle production in p-Pb collisions at $\sqrt{s_{\rm NN} }$= 5.02 TeV
We report measurements of the primary charged-particle pseudorapidity density and transverse momentum distributions in p-Pb collisions at sNN=5.02TeV and investigate their correlation with experimental observables sensitive to the centrality of the collision. Centrality classes are defined by using different event-activity estimators, i.e., charged-particle multiplicities measured in three different pseudorapidity regions as well as the energy measured at beam rapidity (zero degree). The procedures to determine the centrality, quantified by the number of participants (Npart) or the number of nucleon-nucleon binary collisions (Ncoll) are described. We show that, in contrast to Pb-Pb collisions, in p-Pb collisions large multiplicity fluctuations together with the small range of participants available generate a dynamical bias in centrality classes based on particle multiplicity. We propose to use the zero-degree energy, which we expect not to introduce a dynamical bias, as an alternative event-centrality estimator. Based on zero-degree energy-centrality classes, the Npart dependence of particle production is studied. Under the assumption that the multiplicity measured in the Pb-going rapidity region scales with the number of Pb participants, an approximate independence of the multiplicity per participating nucleon measured at mid-rapidity of the number of participating nucleons is observed. Furthermore, at high-pT the p-Pb spectra are found to be consistent with the pp spectra scaled by Ncoll for all centrality classes. Our results represent valuable input for the study of the event-activity dependence of hard probes in p-Pb collisions and, hence, help to establish baselines for the interpretation of the Pb-Pb data.
122716775
Elliptic flow of strange and multi-strange particles in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76-TeV measured with ALICE
118604753
Strange and multi-strange particle production in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV with ALICE
We present ALICE results on strange and multi-strange hadron production as a function of centrality in Pb-Pb collisions at $\sqrt{s_{{\rm NN}}} = 2.76~{\rm TeV}$ at the LHC. Their transverse momentum spectra, yields and particle ratios are compared to the corresponding measurements in pp collisions to address strangeness enhancement and high pT particle suppression. The results are also compared to measurements at RHIC and SPS energies.
120878684
Important observables from the BRAHMS experiment
We present the important observables from the BRAHMS experiment for establishing the properties of the hot and dense strongly interacting QCD matter with respect to its formation, evolution and its effects on high p Tparticle production.