16646090
Two-dimensional dynamical triangulation using the grand-canonical ensemble
Abstract The string susceptibility exponents of dynamically triangulated two dimensional surfaces with sphere and torus topology were calculated using the grand-canonical Monte Carlo method. We also simulated the model coupled to d-Ising spins (d=1,2,3,5).
119109017
Introducing Dynamical Triangulations to the Type IIB Superstrings
In order to consider non-perturbative effects of superstrings, we try to apply dynamical triangulations to the type IIB superstrings. The discretized action is constructed from the type IIB matrix model proposed as a constructive definition of superstring theory. The action has the local N=2 supersymmetry explicitly, and has no extra fermionic degrees of freedom. We evaluate the partition function for some simple configurations and discuss constraints required from the finiteness of partition functions.
7823466
Gaussian and mean field approximations for reduced Yang-Mills integrals
In this paper, we consider bosonic reduced Yang-Mills integrals by using some approximation schemes, which are a kind of mean field approximation called gaussian approximation and its improved version. We calculate the free energy and the expectation values of various operators including Polyakov loop and Wilson loop. Our results nicely match to the exact and the numerical results obtained before. Quite good scaling behaviors of the Polyakov loop and of the Wilson loop can be seen under the 't Hooft like large-N limit for the case of the loop length smaller. Then, simple analytic expressions for the loops are obtained. Furthermore, we compute the Polyakov loop and the Wilson loop for the case of the loop length sufficiently large, where with respect to the Polyakov loop there seems to be no known results in appropriate literatures even in numerical calculations. The result of the Wilson loop exhibits a strong resemblance to the result simulated for a few smaller values of N in the supersymmetric case.
18734752
Grand-Canonical Simulation of Two-Dimensional Simplicial Gravity
The string susceptibility exponents of dynamically triangulated 2-dimensional surfaces with various topologies, such as a sphere, torus and double-torus, were calculated by the grand-canonical Monte Carlo method. These simulations were made for surfaces coupled to $d$-Ising spins ($d$=0,1,2,3,5). In each simulation the area of surface was constrained to within 1000 to 3000 of triangles, while maintaining the detailed-balance condition. The numerical results show excellent agreement with theoretical predictions as long as $d \leq 2$.
15426340
Type IIB Random Superstrings
We consider random superstrings of type IIB in $d$-dimensional space. The discretized action is constructed from the supersymetric matrix model, which has been proposed as a constructive definition of superstring theory. Our action is invariant under the local N=2 super transformations, and doesn't have any redundant fermionic degrees of freedom.
119478986
A Hadron blind detector for the PHENIX experiment at RHIC
The PHENIX collaboration has designed a conceptually new Hadron Blind Detector (HBD) for electron identification in high density hadron environment. The HBD will identify low momentum electron-positron pairs to reduce the combinatorial background in the mass region below 1 GeV/c2. The HBD shall be installed in PHENIX during the 2007 physics run.The HBD is a windowless proximity focusing Cherenkov detector with a radiator length of 50 cm, CsI photocathode and three layers of Gas Electron Multipliers (GEM) for gas amplification. Pure CF4 serves both as a radiator and as a detector gas. The radiation budget of the device is less than 3% of a radiation length.
121311036
Commissioning of the Muon track reconstruction in the ATLAS experiment
125122742
J/psi production in Cu+Cu and Au+Au collisions at RHIC-PHENIX
123022232
Commissioning of the ATLAS level1 endcap muon trigger system
Abstract The ATLAS level1 endcap muon trigger system at the LHC selects interesting events containing muons with transverse momenta greater than 6 GeV/c from 40 MHz proton–proton collisions. This system consists of 3588 Thin Gap Chambers (TGC) and the total number of readout channels is 3.18×105. The trigger logic is based on the coincidence between 7 layers of TGC. All processes are performed using hardware within the maximum latency of 2.5 μ s for the level1 trigger. To be ready for the first beam collisions scheduled in 2009, we have succeeded in sending trigger signals of cosmic ray muons with the synchronous operation at 40 MHz and fine signal timing alignments. During the single proton beam circulation at the LHC in 2008, we have also confirmed that the timing of the endcap muon trigger for tracks of beam halo muons produced at the collimator was well aligned. We report on the status of the commissioning and results from runs with cosmic ray muons and single beams.
10281433
Evaluation of test structures for the novel n + -in-p pixel and strip sensors for very high radiation environments
Abstract Radiation-tolerant n + -in-p silicon sensors were developed for use in very high radiation environments. Novel n + -in-p silicon strip and pixel sensors and test structures were fabricated, tested and evaluated, in order to understand the designs implemented. The resistance between the n + implants (interstrip resistance), the electric potential of the p-stop, and the punch-through-protection (PTP) onset voltage were measured before and as a function of fluence after irradiation. The technology computer-aided design (TCAD) simulations were used to understand the radiation damage and fluence dependence of the structures. The decrease in the interstrip resistance is a consequence of increased leakage current. The decrease in the electric potential of the p-stop results from a build-up of positive charge in the silicon–silicon oxide interface. The decrease and subsequent increase in the PTP onset voltages results from the interface charge build-up and an increase in acceptor states.