Parton fragmentation functions

The field of fragmentation functions of light quarks and gluons is reviewed. In addition to integrated fragmentation functions, attention is paid to the dependence of fragmentation functions on transverse momenta and on polarization degrees of freedom. Higher-twist and di-hadron fragmentation functions are considered as well. Moreover, the review covers both theoretical and experimental developments in single-inclusive hadron production in electron-positron annihilation, deep-inelastic lepton-nucleon scattering, and proton-proton collisions.

/pdf/parton-fragmentation-functions-33z4y02wdl.pdf

Parton Fragmentation Functions

Measurement of inclusive particle spectra and test of MLLA prediction in e+e− annihilation at s=58Gev

Measurement of the inclusive cross section of jets in γγ interactions at TRISTAN

The time projection chamber (TPC) was originally proposed to permit full reconstruction of events of up to 20 particles at an electron–positron collider. It was intended to provide 3D information for tracking and momentum measurement together with particle identification by multiple ionization sampling, in a compact detector. This powerful combination soon found applications in other fields: at one extreme, for studies of rare events of simple structure; at the other, for heavy ion collisions, handling ever higher particle densities, finally up to several thousand tracks in a single event, still providing information on a track-to-track basis.Basic physics, performance and limitations of drift chambers in general will be discussed first. Then the characteristics of TPCs will be introduced, as well as their practical realization and performance. The development from the first TPC, 30 years ago, to the present day will be covered and followed by a few final comments on the ongoing studies for future applications.

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Time projection chambers

A Time Projection Chamber (TPC) is under construction for the TOPAZ e + e − experiment at TRISTAN. The dimension of the TPC is 260 cm in diameter and 300 cm in axial length. Fin-type fine field cages are set inside GFRP insulator cylinders which also serve as the pressure container. The sector is made of multilayer G10 boards for better electric and thermal isolation. The cathode pads are substantially larger in area than those of the PEP4-TPC and having zigzag-shaped boundary. These serve to maintain high spatial resolution with fewer number of pad channels. Signals are amplified by low noise preamplifiers and shaping amplifiers, and, stored and digitized by FASTBUS based CCD-digitizers. Digitized information is preprocessed and sent to VAX 11/780 at a rate 2 MHz per 32 bit word. Nitrogen LASER beam will be used extensively with the LASER beacon system for calibration. Test results on production prototypes are also reported.

The Topaz Time Projection Chamber

The signals from the TOPAZ Time Projection Chamber, after being processed by a low noise preamplifier and a shaper amplifier, are recorded by a CCD based digitizer system. The system achieved an integral operation in the environment of FASTBUS with Sector Sequencers and FPI.

Signal Processing for the TOPAZ Time Projection Chamber

The TOPAZ-TPC has been tested using cosmic ray muons. We present results on resolutions of dE/dx and position measurements in Argon 90% + Methane 10% at 4 atmospheres.

TOPAZ-TPC Cosmic Ray Test

TheTOPAZ-TPChasbeentested using cosmic ray muons.Wepresent results onresolutions ofdE/dxand position measurements inArgon90%+ Methane 10% at4atmospheres.

http://ieeexplore.ieee.org/iel5/23/4337283/04337400.pdf

S. Iwata

Papers

The Topaz Time Projection Chamber

Signal Processing for the TOPAZ Time Projection Chamber

TOPAZ-TPC Cosmic Ray Test

Topaz-tpccosmicray test