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.
119528597
Branes and mirror symmetry in N = 2 supersymmetric gauge theories in three dimensions
We use brane configurations and SL(2, Z) symmetry of the type IIB string to construct mirror N = 2 supersymmetric gauge theories in three dimensions. The mirror map exchanges Higgs and Coulomb branches, Fayet-Iliopoulos and mass parameters and U(1)R symmetries. Some quantities that are determined at the quantum level in one theory are determined at the classical level of the mirror. One such example is the complex structure of the Coulomb branch of one theory, which is determined quantum mechanically. It is mapped to the complex structure of the Higgs branch of the mirror theory, which is determined classically. We study the generation of N = 2 superpotentials by open D-string instantons in the brane configurations.
122716775
Elliptic flow of strange and multi-strange particles in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76-TeV measured with ALICE
119264215
A model of nuclear recoil scintillation efficiency in noble liquids
Abstract Scintillation efficiency of low-energy nuclear recoils in noble liquids plays a crucial role in interpreting results from some direct searches for weakly interacting massive particle (WIMP) dark matter. However, the cause of a reduced scintillation efficiency relative to electronic recoils in noble liquids remains unclear at the moment. We attribute such a reduction of scintillation efficiency to two major mechanisms: (1) energy loss and (2) scintillation quenching. The former is commonly described by Lindhard’s theory and the latter by Birk’s saturation law. We propose to combine these two to explain the observed reduction of scintillation yield for nuclear recoils in noble liquids. Birk’s constants kB for argon, neon and xenon determined from experimental data are used to predict noble liquid scintillator’s response to low-energy nuclear recoils and low-energy electrons. We find that energy loss due to nuclear stopping power that contributes little to ionization and excitation is the dominant reduction mechanism in scintillation efficiency for nuclear recoils, but that significant additional quenching results from the nonlinear response of scintillation to the ionization density.
108585326
Trigger electronics for the Alice PHOS detector
Abstract The Photon Spectrometer of ALICE consists of 5 identical modules of 56×64 PWO crystals with a total of 100° azimuthal coverage of the barrel. The electronics required for implementing both the L0 trigger for high luminosity p–p physics and the L1 trigger for high p T Pb+Pb physics has been studied. A full integration of the trigger logic into the detector's enclosure is based on analog transmission of fast trigger sums between stacks of front-end boards and trigger-router units. The latter contain 112 digitizer channels of 10 bit, which are mapped into a single FPGA per trigger unit, covering areas of 24×16 crystals. The running modes allow for Level-0 trigger at 800 ns and Level-1 at 6200 ns trigger latencies. The design and status of the PHOS trigger electronics are outlined.
119881658
Cold nuclear matter effects on the color singlet J /ψ production in d Au collisions at energies available at the BNL Relativistic Heavy Ion Collider
We use a Modified DKLMT model (called M-DKLMT model) to study the cold nuclear matter (CNM) effects on the color singlet J/psi production in dAu collisions at RHIC. The cold nuclear effect of dipole-nucleus interactions has been investigated by introducing a nuclear geometric effect function f({\xi}) to study the nuclear geometry distribution effect in relativistic heavy-ion collisions. The dependencies of nuclear modification factors (RdA) on rapidity and centrality are studied and compared to experimental data. It is found that the M-DKLMT model can well describe the experimental results at both forward- and mid-rapidity regions in dAu collisions at RHIC.