15071400
LCD ROOT simulation and analysis tools
The North American Linear Collider Detector group has developed a simulation program package based on the ROOT system. The package consists of Fast simulation, the reconstruction of the Full simulated data, and physics analysis utilities.
56000332
PROGRESS OF DESIGN STUDY OF INTERACTION REGION QUADRUPOLES FOR THE SUPER-KEKB
For KEKB upgrade, we are studying the design of the final focus quadrupoles to achieve very small β-functions at the interaction point (IP). For each beam, the final beam focusing system consists of quadrupole-doublet of the superconducting and permanent magnets. In this paper, the design progress of final focusing magnets is reported.
16601897
Mechanisms affecting performance of the BaBar resistive plate chambers and searches for remediation
The BaBar experiment at PEPII relies on the instrumentation of the flux return (IFR) for both muon identification and KL detection. The active detector is composed of resistive plate chambers (RPCs) operated in streamer mode. Since the start of operation the RPCs have suffered persistent efficiency deterioration and dark current increase problems. The ‘‘autopsy’’ of bad BaBar RPCs revealed that in many cases uncured linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil ‘‘stalagmites’’ bridging the 2mm gap. In this paper, a possible model of this ‘‘stalagmite’’ formation and its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. ARTICLE IN PRESS *Corresponding author. Tel.: +1-609-258-4391; fax: +1-609-258-6360. E-mail address: changguo@princeton.edu (C. Lu). 0168-9002/03/$ see front matter r 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0168-9002(03)01292-0 Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently, the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement. r 2003 Elsevier Science B.V. All rights reserved.
13435498
Study of top-quark production and decay vertices with LCD fast simulation
We report a study of top-quark reconstruction in e+e−→tt events at a 500 GeV linear collider using the LCD Fast simulator. The initial study of top-quark anomalous couplings is also reported. The final states of 4 jets and lepton as well as 6 jets are used. Using the 4 jets and lepton final state, we estimate the preliminary sensitivities for form factors at the γ/Z0tt vertex. In the 6 jets reconstruction, we show abilities of the top-quark charge identification and the c-quark tagging in W decays.
54880563
Design and Status of the SuperKEKB Accelerator Control Network System
We have upgraded the accelerator control network system for SuperKEKB, the next generation B-factory experiment in Japan. The designed network system has the higher performance based on the wider bandwidth data transfer, and more reliable and redundant configuration. For the SuperKEKB beamline construction and accelerator components maintenance, we have installed the new wireless network system consists with the Leaky Coaxial (LCX) cable antennas and collinear antennas into the 3 km circumference accelerator tunnel. In this paper, we describe the design and current status of the SuperKEKB accelerator control network system.
55994477
BEAM BACKGROUND AND MDI DESIGN FOR SUPERKEKB/BELLE-II
The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab −1 before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8 × 10 35 cm −2 s −1 . With the increased luminosity, the beam background will be severe. The development of MachineDetector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB and our countermeasures for them, such as collimators to stop Touschek-scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.
120551306
Experimental Search for Kaonic Nuclear Bound States in the 4He(stopped K-,n) Reaction
We made an experimental search for deeply bound kaonic nuclear states ppnK - in 4 He(stopped K - , n) reaction. The experiment is performed in September and October 2002 and the analysis is in progress. The experimental procedure and the present status of the analysis are described.
22969599
Conceptual design of a radial vane silicon tracker for a new measurement of the muon anomalous magnetic moment g-2 and electric dipole moment at J-PARC
A new measurement of the anomalous magnetic moment (g-2) and electric dipole moment (EDM) of the positive muon at J-PARC is proposed. In this experiment, we plan to use a radial vane silicon detector for detecting muon decay positrons. Specification and design study of the detector has been promoted. In order to determine detector parameters, we are developing simulation and positron track reconstruction tools. First version of those using Geant4 and Hough transform method in ideal condition was constructed. We are improving these tools close to real condition and the multi-track finding efficiency has been investigated. In this paper, we report the progress of the studies in simulation and track finding tools for the optimization of the detector parameters.
37764222
Specification and design of a radial vane silicon tracker for a new measurement of the muon anomalous magnetic moment g-2 and electric dipole moment at J-PARC
A new measurement of the anomalous magnetic moment (g-2) and electric dipole moment (EDM) of the positive muon at J-PARC is proposed. In this experiment, we plan to use a radial vane silicon detector for detecting muon decay positrons. Specification and design study of the detector has been promoted. In order to confirm validity of use of the radial vane silicon detector and decide detector parameters, we are developing simulation and positron track reconstruction tools. First version of those using Geant4 and Hough transform method in ideal condition was constructed and the track finding efficiency was investigated. In parallel, for understanding the detector response, we began to test the most recent double sided silicon strip detector in existence. In this paper, we report the progress of the simulation and the experimental studies for the optimization of the detector parameters.
123376999
Development of a super-fluid 4He target system for an experimental search for nuclear K¯ states
Abstract A super-fluid He 4 target system has been successfully developed to experimentally search for deeply bound K ¯ nuclei. From the experimental requirements, the amount of material around the liquid-helium target was drastically suppressed by using two approaches. One was to utilize the properties of super-fluid helium of extremely high thermal conductivity and low vapor pressure. The other was to develop a thin-walled CFRP vacuum chamber and a PET-based target cell. The wall thickness of the CFRP vacuum chamber was only 0.9 mm with the inner diameter of 310 mm. The dimensions of the target cell were 200 mm inner diameter and 150 mm length with the volume of 4.7 l, and it equipped 75 μ m thick beam windows made of a PET film. The present target system achieved a temperature of 1.3 K, and was stably operated throughout the experiment with the operational pressure below 40 mbar and a liquid-helium consumption rate of 45 l / day .
73685731
Flux tube model for glueballs
We calculate the mass spectra and decay widths of glueballs in the flux tube model. The glueball is assumed to be a flux tube ring. The breathing and the rotational motions are investigated using the WKB approximation. The calculated spectrum is consistent with those obtained by lattice QCD. The decay widths are also computed using the Schwinger mechanism, and it is shown that they have rather large values. It is widely believed that the strong interaction is de- scribed by quantum chromodynamics ~QCD !@ 1#. It is, how- ever, very difficult to solve QCD, so that several effective models have been devised to explain the physical properties of many hadrons. The flux tube model @2#, or hadron string model @3,4#, is one such model. According to this model, mesons are made up of a quark and antiquark connected by a color flux tube and baryons are described by a quark and diquark connected by the same flux tube. We showed in a previous paper @5# that various excited states of the hadrons can be explained systematically using such a simple model. On the other hand, recent lattice QCD simulations @6# predict the existence of glueballs, which are composed of only gluons. It is the purpose of this paper to present an intuitive and analytic approach to glueballs using a flux tube model. We assume that the glueball is a closed color flux tube ~flux tube ring !. Moreover, the flux tube that constitutes the ring is assumed to have the same properties as the flux tube that constitutes a meson or a baryon. Consequently, our model has no free parameter. We study the relativistic motion of the closed string and obtain the mass spectrum of the glueballs. This simple picture has already been considered by several authors. In particular, Koma, Suganuma, and Toki @7# studied the relativistic breathing motion analytically with the use of the dual Ginzburg-Landau theory @ 8-1 0#. We study not only the vibrational motion but also the rotational one. Moreover, the decay widths in @7# are also calculated by taking into account qqpair production inside the flux tube ~Schwinger mechanism!. This paper is organized as follows. In the next section, the flux tube model for the glueballs is formulated. Section III is devoted to calculation of the mass spectra and the decay widths of the glueballs. In Sec. IV, the numerical results are presented and some discussion is given.