8622370
Estimation of Impact Parameter on event-by-event basis in Nuclear Emulsion Detector
Photographic Nuclear Emulsion Detector (PNED) has been in use in nuclear and particle physics experiments from the begining, often as the major detector system. However, direct measurement of impact parameter in this detector does not seem possible due to some limitations. This paper discribe a simple yet strong method to estimate the impact parameter of events on event-by-event basis. Though this method is develpoed specifically for the photographic nuclear emulsion detector, we envision that it should also be applicable to other multi-target detector systems.
118409510
Characteristics of alpha projectile fragments emission in interaction of nuclei with emulsion
The properties of the relativistic alpha fragments produced in interactions of 84Kr at around 1 A GeV in nuclear emulsion are investigated. The experimental results are compared with the similar results obtained from various projectiles with emulsion interactions at different energies. The total, partial nuclear cross-sections and production rates of alpha fragmentation channels in relativistic nucleus-nucleus collisions and their dependence on the mass number and initial energy of the incident projectile nucleus are investigated. The yields of multiple alpha fragments emitted from the interactions of projectile nuclei with the nuclei of light, medium and heavy target groups of emulsion-detector are discussed and they indicate that the projectile-breakup mechanism seems to be free from the target mass number. It is found that the multiplicity distributions of alpha fragments are well described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The mean multiplicities of the freshly produced or newly created charged secondary particles, normally known as shower and secondary particles associated with target in the events where the emission of alpha fragments were accompanied by heavy projectile fragments having Z ≥ 3 seem to be constant as the alpha fragments multiplicity increases, and exhibit a behavior independent of the alpha fragments multiplicity.
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.
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.
119072934
Transverse mass spectra and scaling of hadrons at RHIC and LHC energies
We present a systematic study of transverse mass spectra ($m_T$) of mesons and baryons at RHIC and LHC energies. In an earlier study, it was shown that all the mesons produced in p+p and d+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV follow $m_T$ scaling while in Au+Au collisions at same energy the mesons with strange and charm quark contents do not follow $m_T$ scaling which can be attributed to medium modifications. 
We extend this study for baryons produced in all above colliding systems at $\sqrt{s_{NN}}$ = 200 GeV. Although all available baryon spectra behave differently from mesons but are found to scale with protons for both p+p and d+Au collisions. In case of Au+Au collisions, the strange baryons behave differently from protons. 
This study has also been performed on the meson spectra in p+p collisions at 62.4 GeV which lies in between the highest RHIC energy and SPS energy where the $m_T$ scaling was first observed and we arrive at same conclusions as those at 200 GeV. 
We test the $m_T$ scaling at LHC with the first meson spectra measured in p+p collisions at 900 GeV and find that the $m_T$ spectra of kaons and $\phi$ do not scale with pions. Thus $m_T$ scaling which was working well up to p+p collisions at 200 GeV seems to be broken. Here we use all data measured in the mid rapidity region. Baryon to meson ratio is studied as a function of $m_T$, at different energies and for different systems and is found that this ratio for p+p at 900 GeV is quite different from that in p+p collisions at RHIC energies.
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.
123629676
Upper bounds on particle-antiparticle total cross section differences at high energies
We derive axiomatic asymptotic upper bounds on particle-antiparticle total cross section differences for pion-nucleon, kaon-nucleon and nucleon-nucleon scattering. Comparison with Serpukhov data is also given.
120083760
Effect of N/Z in pre-scission neutron multiplicity for 16,18O+194,198Pt systems
This paper report the summary of the experimental results of pre-scission neutron multiplicities from four compound nuclei, namely 210,212,214,216 Rn, and statistical model analysis of the corresponding data. The compound nuclei 210,212,214,216 Rn having N/Z values as 1.441, 1.465, 1.488, 1.511 respectively are populated through the 16,18 O+ 194,198 Pt reactions at excitation energies of 50, 61, 71.7 and 79 MeV. The measured neutron multiplicities are further analyzed with the statistical model of nuclear decay where fission hindrance due to nuclear dissipation is considered. The N/Z dependence of the dissipation strength at lowest excitation energy of the compound nuclei suggests shell closure effects. However, such effects are not observed at higher excitations where the variation of the dissipation strength with N/Z does not show any specific trend. The variation of N/Z in fission time scale is also shown.
123580858
Unitarity upper bound on the absorptive parts of elastic scattering amplitudes
We derive a unitarity upper bound on the absorptive part A(s, t) of the elastic-scattering amplitude in the physical region. In the diffraction peak region the bound on A(s, t)/A(s, 0) is a function only of the parameter σ tot 2 (−t)/4πσ el . Assuming the diffraction scattering to be purely absorptive and spin independent we find the pp, pp, and π ± p data to lie a little below the theoretical upper bound. Further the experimental curve of X(t)/X(0) vs −4tX(0)/σ el , where X(t)≡dσ/dt, seems "universal."
120331693
Bianchi Type-I Cosmological Model Filled with Viscous Fluid in a Modified Brans-Dicke Cosmology
Adding the cosmological term, which is assumed to be variable in Brans-Dicke theory we have discussed about a Bianchi type-I cosmological model filled with viscous fluid with free gravitational field of Petrov type-D. The effect of viscousity on various kinematical parameters has been discussed. Finally, this model has been transformed to the original form (1961) of Brans-Dicke theory including a variable cosmological term.
9833237
Measurement of the damping of the nuclear shell effect in the doubly magic 208Pb region.
The damping of the nuclear shell effect with excitation energy has been measured through an analysis of the neutron spectra following the triton transfer in the (7)Li induced reaction on (205)Tl. The measured neutron spectra demonstrate the expected large shell correction energy for the nuclei in the vicinity of doubly magic (208)Pb and a small value around (184)W. A quantitative extraction of the allowed values of the damping parameter γ, along with those for the asymptotic nuclear level density parameter ã, has been made for the first time.