123203919
Factorization of fragmentation cross-sections in heavy-ion collisions at 1A GeV
Fe-, Kr- and Xe-induced heavy-ion reactions at ~ 1 A GeV show factorization in the production cross-sections only for light fragments. Both "strong" and "weak" factorization are found for light fragments. The cross-sections of these fragments are described in detail within the prescription of cold breakup of spectator residues.
124164538
Low Energy Neutrino and Dark Matter Physics with sub‐keV Germanium Detectors
A TEXONO collaboration research program on low energy neutrino and dark matter physics is going on at the Kuo‐Sheng Neutrino Laboratory (KSNL). Collaboration main goals are to measure the neutrino‐nucleus coherent scattering cross section, neutrino magnetic moments, and the searches of WIMP dark matter. To achieve these goals various prototype detectors and their sub‐keV background are under study. A threshold of 220 eV was achieved with prototype detectors at the KSNL. New limits were set for WIMPs with mass between 3‐6 GeV. Data are being taken with a 500 g Point Contact Germanium detector, where a threshold of ∼350 eV was demonstrated. A 20 g ULEGe detector is taking data at CJPL in Sichuan, China.
199685807
Search of axions from a nuclear power reactor with a high-purity germanium detector
This article reports the first study of possible emissions of axions from power reactors using Primakoff and Compton conversions as the detection mechanisms. The expected experimental signatures are mono-energetic lines produced by their Primakoff or Compton conversions at a high-purity germanium (HPGe) detector. No evidence of axion emissions were observed and constraints on axion couplings versus axion mass within the framework of invisible axion models were placed. This experimental approach provides a unique probe for axion mass at the keV-MeV range not accessible to the other techniques.
117487117
The TEXONO research program on low-energy neutrino and astroparticle physics
AbstractThis article reviews the research program and efforts of the TEXONO Collaboration on neutrino and astroparticles. The main program is on reactor-based low-energy neutrino physics at the Kuo-Sheng Power Plant in Taiwan. The facilities of the laboratory are described. A limit on the neutrino magnetic moment of μν(
$$\bar \nu _e $$
) < 1.3 × 10−10 μB at 90% C.L. has been achieved from measurements with a high-purity germanium detector. Other research programs at Kuo-Sheng are surveyed.
16990556
Effective dynamic range in measurements with flash analog-to-digital convertor
Flash Analog-to-Digital Convertor (FADC) is frequently used in Nuclear and Particle Physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal 28 value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(TI) crystal scintillators. The effective dynamic range can be extended by at least four more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout. (C) 2003 Elsevier B.V. All rights reserved.
119107308
Hadron spectra in p+p collisions at RHIC and LHC energies
We present the systematic analysis of transverse momentum (pT) spectra of identified hadrons in p+p collisions at Relativistic Heavy Ion Collider ( and 200 GeV) and at Large Hadron Collider (LHC) energies (, 2.76 and 7.0 TeV) using phenomenological fit functions. We review various forms of Hagedorn and Tsallis distributions and show their equivalence. We use Tsallis distribution which successfully describes the spectra in p+p collisions using two parameters, Tsallis temperature T which governs the soft bulk spectra and power n which determines the initial production in partonic collisions. We obtain these parameters for pions, kaons and protons as a function of center-of-mass energy . It is found that the parameter T has a weak but decreasing trend with increasing . The parameter n decreases with increasing which shows that production of hadrons at higher energies are increasingly dominated by point like qq scatterings. Another important observation is with increasing , the separation between the powers for protons and pions narrows down hinting that the baryons and mesons are governed by same production process as one moves to the highest LHC energy.
120319641
Fractionally-charged atomic systems and the Stanford quark-search experiments
Abstract The binding energies for the one- and two-electron systems (fe−), (fe−e−), (ffe−) and (ffe−e−) containing fractionally-charged objects f are calculated. Results are given for the fractional-charge values 1 3 , 2 3 and 4 3 . A possible explanation of the experimental results of the Stanford group is given in terms of these. Our results seem to prefer the value 2 3 suggesting that one of the possibilities for f is that is might be a liberated u-quark.
121929737
Factorization limit on photon-photon cross section
A lower bound on the photon-photon total cross section following from factorization of Regge singularities is presented. The bound seems to lie quite close to the recent PETRA measurements when the gamma-gamma c.m. energy is above 6 GeV.
120629215
Path-integral formulation of scattering theory: Central potentials
We consider central-potential scattering and determine a path-integral representation for the S matrix in polar coordinates. This is obtained by transforming to polar coordinates a Cartesian form of the nonrelativistic S matrix given by Campbell et al., and implementing an idea of Faddeev to obtain the appropriate asymptotic conditions. Our results are applied to scattering in an inverse-square potential to determine the correct phase shifts as well as the S matrix.
120223172
psi particles, SU(4), and anomalous currents
We propose assignment of the new ψ particles in an SU(4) symmetry scheme, incorporating SU(3) and a new additive quantum number, paracharge Z. Anomalous currents are introduced to account for the production and decays of these particles. Two more rather broad resonances at around 4.3 and 5.0 (±0.2) GeV are expected in the e + e - annihilation, one of which has recently been reported (at 4.15 GeV).
119488343
Including beta- and gamma- Vibrations in Evaluating the Ground State Rotational Band of Deformed Even-Even Nuclei
From the semi-empirical formalisms of Bohr-Mottelson, a new model, based on the effect of beta- and gamma- head energies and the variable moment of inertia, was developed to calculate the ground state rotational band of almost all deformed e-e nuclei. The model can be tuned for nuclei with experimentally available beta- and gamma-vibrational energies as well as for those with unmeasured beta- and gamma-vibrations.