119193457
Two source emission behavior of projectile fragments alpha in 84Kr interactions at around 1 GeV per nucleon
The emission of projectile fragments alpha has been studied in 84Kr 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.
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.
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.
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.
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.
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.
54620466
Measuring the level of nuclear activity in Seyfert galaxies and the unification scheme
Context. The unification scheme of Seyfert galaxies hypothesizes that Seyfert type 1s and type 2s are intrinsically similar and the observed differences between the two subtypes are solely due to the differing orientations of toroidal-shaped obscuring material around the AGN. In the framework of the unification scheme, both the Seyfert subtypes are expected to show similar intrinsic nuclear properties such as the absorption-corrected AGN X-ray luminosity, bolometric luminosity, accretion rate and the mass of the supermassive black hole. Aims. To test the predictions of the Seyfert unification scheme, we make statistical comparison of the distributions of: (i) the absorption-corrected 2.0‐10 keV X-ray luminosities; (ii) the bolometric luminosities; (iii) the black hole masses and; (iv) the Eddington ratios, of Seyfert type 1s and type 2s. Methods. We use an optically selected Seyfert sample in which type 1s and type 2s are matched in properties that are independent to the orientation of the obscuring torus, the AGN axis and the host galaxy. Results. The distributions of the absorption-corrected 2.0‐10 keV X-ray luminosities (L c.0−10 keV ), the bolometric luminosities (LBol), the black masses (MBH) and, the Eddington ratios (λ) are statistically similar for the two Seyfert subtypes, consistent with the orientation and obscuration based Seyfert unification scheme. The Eddington ratio distributions suggest that both the Seyfert subtypes are accreting at sub-Eddington level with wide span of Eddington ratios i.e., 10 −4 ‐10 −1 .
122369339
Electron identification and the detection of synchrotron radiation with a preshower detector
Abstract Results are presented from testbeam measurements made with a scintillating fiber preshower detector. The detector was designed to study the early development of electromagnetic showers and the conversion of synchrotron radiation photons. It was constructed with a 0.5 mm transverse granularity, and eight 0.25 radiation length ( X 0 ) longitudinal samplings. Data were taken with 50 GeV pions and electrons with energies between 10 and 200 GeV. Measurements, for electrons, of both the energy deposited and the shower width as a function of depth are presented in this paper. In addition, data were taken with a 1.8 m long magnet with a 2.5 T field placed directly upstream of the detector and the synchrotron radiation photons, generated by the electrons traversing it, were observed in our detector. Electron identification efficiencies and pion rejection factors based on the synchrotron radiation signal and the energy deposited in the last sampling layer (1.75 X 0 ) are presented.
119464132
Causal quantum mechanics treating position and momentum symmetrically
De Broglie and Bohm formulated a causal quantum mechanics with a phase space density whose integral over momentum reproduces the position probability density of the usual statistical quantum theory. We propose a causal quantum theory with a joint probability distribution such that the separate probability distributions for position and momentum agree with the usual quantum theory. Unlike the Wigner distribution the suggested distribution is positive-definite and obeys the Liouville condition.
117752946
Study of neutron-induced background and its effect on the search of 0$\nu\beta\beta$ decay in $\rm^{124}Sn$
Neutron-induced background has been studied in various components of the TIN.TIN detector, which is under development for the search of Neutrinoless Double Beta Decay in $\rm^{124}Sn$. Fast neutron flux $\sim10^{6}~n~cm^{-2}s^{-1}$ covering a broad energy range ($ \sim0.1$ to $ \sim18$~MeV) was generated using $^{9}Be(p,n)^{9}B$ reaction. In addition, reactions with quasi-monoenergetic neutrons were also studied using $^{7}Li(p,n)^{7}Be$ reaction. Among the different cryogenic support structures studied, Teflon is found to be preferable compared to Torlon as there is no high energy gamma background ($E_\gamma >$ 1 MeV). Contribution of neutron-induced reactions in $\rm ^{nat, 124} $Sn from other Sn isotopes (A = 112 -- 122) in the energy region of interest, namely, around the $Q_{\beta\beta}$ of $\rm^{124}Sn$ ($E \sim$ 2.293 MeV), is also investigated.
121300042
Fractional Total Charge Eigenvalues for a Fermion in a Finite One-dimensional Box
Abstract We show that the Jackiw-Rebbi and Goldstone-Wilczek hamiltonians describing a two-component Dirac fermion in bounded background field and confined to a finite one-dimensional box has self-adjoint extensions which are labelled by a 2 × 2 unitary matrix U . The fractional part of the eigenvalue of the total vacuum charge N 0 is found to be given by α π where det U = −exp(21 α ). The (non-periodic) boundary condition U = 1 models the Jackiw-Rebbi infinite space solitonic situation leading to half-odd integral N 0 .