119187939
Two source emission behaviour of alpha fragments of projectile having energy around 1 GeV per nucleon
84 Kr interactions with nuclei of the nuclear emulsion detector composition at relativistic energy below 2 GeV per nucleon. The angular distribution of projectile fragments alpha in terms of transverse momentum could not be explained by a straight and clean-cut collision geometry hypothesis of Participant – Spectator (PS) Model. Therefore, it is assumed that projectile fragments alpha were produced from two separate sources that belong to the projectile spectator region differing drastically in their temperatures. It has been clearly observed that the emission of projectile fragments alpha are from two different sources. The contribution of projectile fragments alpha from contact layer or hot source is a few percent of the total emission of projectile fragments alphas. Most of the projectile fragments alphas are emitted from the cold source. It has been noticed that the temperature of hot and cold regions are dependent on the projectile mass number. Nuclear fragmentation is an important experimental phenomenon in nucleus – nucleus collisions at relativistic high energy and heavy ion [1]. The PS Model is a simple and basic model for the study of the high energy nucleus – nucleus collisions. The emission of projectile fragments alpha has been studied in lots of high energy heavy ion experiments having energy more than a GeV per nucleon and the general consensus was that they are coming out from the projectile spectator part in the context of a PS Model [2]. According to the PS Model, the interacting system in high energy nucleus – nucleus collisions can be clearly divided into three regions such as target and projectile spectators and a participant region. The overlapping region of the two colliding nuclei is called the participant region and the other regions are called the target and the projectile spectators, respectively. Data from lighter projectiles has been successfully explained with the help of PS Model but data from heavy ion interactions pointed finger towards the PS Model because experiments observed many projectile fragments alpha having larger emission angle that could not be explained by the straight and clean-cut collision geometry picture of the PS Model. Therefore, this large angle scattering indicated the failure of the PS Model and forced us to rethink and modify this model according to the physics requirements and the idea of multiple sources i.e. emission of projectile fragments alpha from different sources having different temperature has been introduced [3]. In this paper, we analyzed the transverse momentum distributions of projectile fragments alpha produced in 84 Kr interactions with the nuclei of the Nuclear Emulsion Detector’s (NED) target at around 1 GeV per nucleon kinetic energy [4]. Experimental techniques are briefly
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.
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.
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.
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.
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.
122262432
Fluctuation theorems for the Feynman fluid model of inclusive reactions
119421763
High precision study of the space distribution of the colour flux in the SU(2) lattice gauge theory
Abstract The work of the Cracow-LSU collaboration on the space structure of the colour fields around the static charges is reported. We find that the large cancellations between the electric and magnetic energy densities lead to a narrow tube.
120606020
UNITARITY UPPER AND LOWER BOUNDS ON THE ABSORPTIVE PARTS OF ELASTIC SCATTERING AMPLITUDES.
We derive upper and lower bounds on the imaginary part of the elastic scattering amplitude of two spinless particles in the physical region, in terms of the elastic cross section σ el and the total cross section σ tot , using unitarity alone. The bounds derived are the best possible ones, given only the stated unitarity constraints. The upper bound for high energies and small values of the momentum transfer squared t has a particularly simple and "universal" form, ImF(s, t)/ImF(s, 0) 2 −(21/320)(ρ/9) 3 +... if 2.5>~ρ≡ρ(−t/4π)σ tot 2 (s)/σ el (s), which depends on the particular scattering process and on the energy and momentum transfer only through the dimensionless parameter ρ. We give explicit formulas and numerical values for the upper bound up to ρ=8.42. We compare the experimental curve of (dσ/dt)/(dσ/dt) t=0 versus 4(−t)(dσ/dt) t=0 /σ el with the theoretical upper bound on [ImF(s, t)/ImF(s, t=0)]] 2 versus ρ. The quantities plotted in the experimental and theoretical curves are the same if the unpolarized cross sections are spin-independent and purely absorptive in the diffraction-peak region. We find that the experimental points for pp, pp, π + p, and π − p scattering in the lab momentum range 6-13 GeV/c fall on a curve lying only slightly below the theoretical upper-bound curve, the difference being less than 10% for ρ in the range (0,3) and less than 25% for ρ in the range (3,5). We further notice that this experimental curve is universal. We also derive unitarity lower bounds on the nth derivatives of the absorptive part at t=0, and on the absorptive part for positive values of t within the Lehmann-Martin ellipse, in terms of σ el and σ tot . The corresponding bounds if σ tot alone is known are also derived.
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.
56310271
Study of the shell effect on nuclear dissipation via neutron multiplicity measurement
Experimental neutron multiplicity data has been fitted using the Kramers' fission width, in statistical model calculations with and without inclusion of shell corrections in nuclear level density, nuclear masses and fission barrier. It has been found that the magnitude of dissipation strength changes to a large extent with inclusion of shell corrections in different ingredients of the statistical model. These observations clearly demonstrate the importance of shell corrections in statistical model calculations.