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The ferromagnet to paramagnet phase transition temperature depends on the dilution concentration in the site diluted Ising ferromagnet. Though this model is a bistable system, few studies reported dynamic phase transition (DPT) in diluted Ising ferromagnet. We study dilution-dependent DPT in diluted Ising ferromagnet via Monte Carlo simulation under a time-varying external field tuning the system’s temperature on several system sizes. The nature of the transition is characterized by employing the finite-size scaling study.

We have studied the collective behaviour of a binary mixture of self-propelled particles (SPPs) with non-identical motile properties. The two types of SPPs with low and high velocity is modelled in a two-dimensional system with periodic boundary conditions (PBCs) at a fixed particle density. The two types have two widely different velocities. The alignment interaction rule and angular noise similar to Vicsek Model (VM) is implemented in this model. Both inter and intra-particle interactions are considered among the SPPs. The system exhibits various self-organised pattern formation and phase segregation which mainly depends on the angular noise present in the system. Without any restriction of interaction or repulsion among the particles, the SPPs phase-separated into dense structures. The orientational order-disorder phase transition is studied, and nontrivial results are obtained. Cluster size distribution (CSD) for the entire system is also studied at the transition region. The CSD exhibits a power-law behaviour at the transition, with an exponent that of the standard percolation.

Textile industries are one of the largest water consuming sectors and wastewater is produced in various steps like pretreatment, dyeing, washing and finishing, etc. Effluent from such industries contains a large amount of unfixed dyes, auxiliary chemicals, alkalis and salt which can cause significant pollution of the surface and groundwater if not adequately treated. The present study is focussed on process development for dye and COD removal from such wastewater using an eco-friendly and cost-effective approach. An integrated process has been used involving application of ceramic UF membrane and biosorptive treatment. Effluent was collected from a textile dyehouse having pH of 12.27, TDS value 38.22 g/L and COD of 3600 mg/L. The highly concentrated effluent was diluted to ten times and was passed through ceramic ultrafiltration (UF) membrane module to reduce organic loading of the wastewater. The permeate from the UF process was further treated with a carbonaceous biosorbent prepared from vegetable waste of household for removal of dyes. Effect of process parameters such as transmembrane pressure (1–5 kg/cm2) and contact time were studied in UF process with respect to the permeate flux and COD removal. Effect of the initial concentration of dyes, pH, temperature and biosorbent dose have been analysed in the biosorption process. Encouraging results were obtained in the integrated process with respect to the dye and organic loading reduction in industrial effluent.

We analyse in detail various multi-level Rydberg excitation schemes which can be used to suppress motional dephasing in optically trapped Cesium atom qubits in the context of quantum information processing. To explore the dephasing mechanism on a quantitative level, we analyse the time evolution of the atom’s wavefunction, under the application of a composite pulse sequence (π − 4π − π), taking into account controllable experimental parameters like the Rabi frequency and temperature. Our study determines the characteristics of a three level system that can be used with this pulse sequence for eliminating motional dephasing. Such systems can hence be directly employed in state-of-the-art quantum simulation and quantum computation experiments to reduce the trap induced decoherence. This paves the way towards the realization of large scale quantum information processing architecture using optically trapped alkali atom qubits.

HLH (Hemophagocytic lymphohistiocytosis) is not an uncommon disorder; it is an overreaction of the immune system. It can be familial or acquired and both share one common feature of a highly stimulated and ineffective immune response. Acquired HLH is commonly seen with infection (infection associated hemophagocytic syndrome-IAHS); malignancies and rheumatic disease where it is also known as (macrophage activating syndrome). Here we are reporting three cases of secondary HLH associated with dengue, typhoid and vivax malaria.

Eliminating atoms of a Bose-Einstein condensate in a lattice from one cell is coherent perfect absorption of the quantum liquid., Coherent perfect absorption is the complete extinction of incoming radiation by a complex potential in a physical system supporting wave propagation. The concept was proven for linear waves in a variety of systems including light interacting with absorbing scatterers, plasmonic metasurfaces, and graphene films, as well as sound waves. We extend the paradigm to coherent perfect absorption of nonlinear waves and experimentally demonstrate it for matter waves in an atomic Bose-Einstein condensate. Coherent absorption of nonlinear matter waves is achieved easier than its linear analogs because the strength of two-body interactions offers additional freedom for control. Implementation of the coherent perfect absorber of Bose-Einstein condensates paves the way toward broad exploitation of the phenomenon in nonlinear optics, exciton-polariton condensates, acoustics, and other areas of nonlinear physics. It also opens perspectives for designing atom lasers.

We employ metastable ultracold $^{173}$Yb atoms to study dynamics in the 1D dissipative Fermi-Hubbard model experimentally and theoretically, and observe a complete inhibition of two-body losses after initial fast transient dynamics. We attribute the suppression of particle loss to the dynamical generation of a highly entangled Dicke state. For several lattice depths and for two- and six-spin component mixtures we find very similar dynamics, showing that the creation of strongly correlated states is a robust and universal phenomenon. This offers interesting opportunities for precision measurements., Comment: 14 pages, 5 figures

One of the important goals of present research is to control and manipulate coherence in a broad variety of systems, such as semiconductor spintronics, biological photosynthetic systems, superconducting qubits and complex atomic networks. Over the past decades, interferometry of atoms and molecules has proven to be a powerful tool to explore coherence. Here we demonstrate a near-field interferometer based on the Talbot effect, which allows us to measure finite-range phase coherence of ultracold atoms in an optical lattice. We apply this interferometer to study the build-up of phase coherence after a quantum quench of a Bose–Einstein condensate residing in a one-dimensional optical lattice. Our technique of measuring finite-range phase coherence is generic, easy to adopt and can be applied in practically all lattice experiments without further modifications., Quantum gas experiments are useful to study non-equilibrium many-body dynamics. Here, the authors demonstrate how the Talbot effect can be used to measure the spreading of phase coherence of ultracold atoms in an optical lattice.

A single trapped Ra + (Z = 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than Z 3. This experiment promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a measurement provides a sensitive test of the Standard Model in particle physics. At the present stage of the experiment, we focus on trapping and laser cooling stable Ba + ions as a precursor for radioactive Ra + . Online laser spectroscopy of the isotopes 209 − 214Ra + in a linear Paul trap has provided information on transition wavelengths, fine and hyperfine structures and excited state lifetimes as test of atomic structure calculations. Additionaly, a single trapped Ra + ion could function as a very stable clock.

The white rot fungus Phanerochaete chrysosporium has been identified to be an environmentally useful microorganism for the degradation of various hazardous pollutants, mainly because of its ligninolytic enzyme system, particularly the lignin peroxidase (LiP) secreted by the fungus. In the present work, the behavior of the fungus in liquid medium due to variation in physico-chemical parameters, i.e., glucose concentration, nitrogen concentration, agitation, etc., was studied. Increment of the initial concentration of glucose in the medium increases the biomass growth and LiP activity, when cultured under controlled conditions. The biomass growth and LiP activity by the fungus was modeled following stochastic approach. The behavior of growth and enzyme activity of the fungus observed from the model were found to be in agreement with the experiments qualitatively.

The hyperfine structure of short-lived trapped Ra-211,209(+) ions was investigated by means of laser spectroscopy. The hyperfine structure constants A and B of the 6d(2)D(3/2) level were determined. There is a 2.2 standard deviation difference between the theoretical and the more accurate experimental value for the B coefficient of Ra-211(+). These measurements provide a test for the atomic theory required for upcoming experiments on atomic parity violation and atomic clocks. (C) 2011 Elsevier B.V. All rights reserved.

Atomic parity violation (APV) experiments are sensitive probes of the electroweak interaction at low energy. These experiments are competitive with and complementary to high-energy collider experiments. The APV signal is strongly enhanced in heavy atoms, and it is measurable by exciting suppressed (M1, E2) transitions. The predicted enhancement factor of the APV effect in the S-D transition in Ra(+) is about 50 times larger than the S-S transition in neutral Cs. However, certain spectroscopic information on Ra+, needed to constrain the required atomic many-body theory, was lacking. Using the AGOR cyclotron and the TRI mu P facility at KVI in Groningen, short-lived (212-214)Ra(+) ions were produced and trapped. First ever excited-state laser spectroscopy was performed on the trapped ions. These measurements provide a benchmark for the atomic theory required to extract the electroweak mixing angle to sub 1% accuracy and are an important step towards an APV experiment in a single trapped Ra(+) ion. A lower bound on the radiative lifetime of the 6(2)D(5/2) state was found of 232(4) ms. This experimental confirmation of the long coherence time of the meta-stable 6(2)D(5/2) state is important in light of the possibility of using a single trapped radium ion as an optical frequency standard.

Atomic parity violation (APV) experiments are sensitive probes of the electroweak interaction at low energy. These experiments are competitive with and complementary to high-energy collider experiments. The APV signal is strongly enhanced in heavy atoms, and it is measurable by exciting suppressed (M1, E2) transitions. The predicted enhancement factor of the APV effect in the S-D transition in Ra+ is about 50 times larger than the S-S transition in neutral Cs. However, certain spectroscopic information on Ra+, needed to constrain the required atomic many-body theory, was lacking. Using the AGOR cyclotron and the TRIμP facility at KVI in Groningen, short-lived 212–214Ra+ ions were produced and trapped. First ever excited-state laser spectroscopy was performed on the trapped ions. These measurements provide a benchmark for the atomic theory required to extract the electroweak mixing angle to sub 1% accuracy and are an important step towards an APV experiment in a single trapped Ra+ ion. A lower bound on the radiative lifetime of the 62D5/2 state was found of 232(4) ms. This experimental confirmation of the long coherence time of the meta-stable 62D5/2 state is important in light of the possibility of using a single trapped radium ion as an optical frequency standard.

Atomic parity violation (APV) can be measured in a single Ra+ ion, enabling a precise measurement of the electroweak mixing angle in the Standard Model of particle physics at low momentum transfer. This provides sensitivity to new particles such as extra Z0 bosons or leptoquarks. The Weinberg angle can be measured via a determination of the light shift in the forbidden 72S1/2–62D3/2 transition in a single trapped Ra+. Ultra-narrow transitions in such an ideal system can also be exploited to realize a high stability frequency standard. At the TRIμP facility of KVI, we have succeeded in the production of a series of radioactive short-lived radium isotopes. The radium isotopes produced were stopped and thermalized to Ra+ in a thermal ionizer, mass separated in a Wien filter, cooled in a gas filled radio frequency quadrupole and subsequently trapped as a cloud in a linear Paul trap. Laser spectroscopy in the trapped radium ions has been performed. The results of hyperfine structure, isotope shift, and lifetime measurements are important experimental inputs to test the accuracy of atomic theory, the precision of which is indispensable for extracting the Weinberg angle. These results are also of relevance for a possible atomic clock, based on trapped Ra+.

Radioactive isotopes produced by the in-flight method are converted into low-energy ions with a thermal ionizer (TI) ion catcher, the operation of which is based on a hot cavity ion source. The extraction efficiency of the TI for different alkali and alkali-earth elements has been studied and compared to a model based on diffusion only. The model describes the stationary limit, i.e. the extraction efficiency, as well as the dynamic response of the TI output when the primary beam is switched on and off.

We have calculated the saturation observables of symmetric nuclear matter and nuclear symmetry energy in the framework of Brueckner-Hartree-Fock (BHF) formalism with Bonn-B potential as two-body interaction, including modification of hadronic parameter inside nuclear medium. We have found that it is possible to understand all the saturation observables of symmetric nuclear matter by incorporating in-medium modification of the parameters of sigma meson alone. Linear density dependent reduction of σ-nucleon coupling constant by about 6.8% and density independent reduction σ-meson mass by about 3.5% is sufficient to understand nuclear matter saturation observables. We find with the calculated symmetry energy that neutron skin thickness of 208Pb is 0.20 fm and the radius of 1.4 solar mass neutron stars as 11.98 ± 0.75 km.

We experimentally study a driven-dissipative Josephson junction array, realized with a weakly interacting Bose-Einstein condensate residing in a one-dimensional optical lattice. Engineered losses on one site act as a local dissipative process, while tunneling from the neighboring sites constitutes the driving force. We characterize the emerging steady states of this atomtronic device. With increasing dissipation strength γ the system crosses from a superfluid state, characterized by a coherent Josephson current into the lossy site, to a resistive state, characterized by an incoherent hopping transport. For intermediate values of γ, the system exhibits bistability, where a superfluid and an incoherent branch coexist. We also study the relaxation dynamics towards the steady state, where we find a critical slowing down, indicating the presence of a nonequilibrium phase transition.

Ultracold quantum gases offer unique possibilities to study interacting many-body quantum systems. Probing and manipulating such systems with ever increasing degree of control requires novel experimental techniques. Scanning electron microscopy is a high resolution technique which can be used for in situ imaging, single site addressing in optical lattices and precision density engineering. Here, we review recent advances and achievements obtained with this technique and discuss future perspectives., Accepted for publication in Journal of Physics B: Atomic, Molecular and Optical Physics as a Topical Review

We try to determine phenomenologically the extent of in-medium modification of σ-meson parameters so that the saturation observables of the nuclear matter equation of state (EOS) are reproduced. To calculate the EOS we have used Brueckner-Bethe-Goldstone formalism with Bonn potential as two-body interaction. We find that it is possible to understand all the saturation observables, namely, saturation density, energy per nucleon and incompressibility, by incorporating in-medium modification of σ-meson-nucleon coupling constant and σ-meson mass by a few per cent.

We report on the observation of negative differential conductivity (NDC) in a quantum transport device for neutral atoms employing a multimode tunneling junction. The system is realized with a Bose-Einstein condensate loaded in a one-dimensional optical lattice with high site occupancy. We induce an initial difference in chemical potential at one site by local atom removal. The ensuing transport dynamics are governed by the interplay between the tunneling coupling, the interaction energy, and intrinsic collisions, which turn the coherent coupling into a hopping process. The resulting current-voltage characteristics exhibit NDC, for which we identify atom number-dependent tunneling as a new microscopic mechanism. Our study opens new ways for the future implementation and control of complex neutral atom quantum circuits.

Transition frequencies were determined for transitions in Ra in an atomic beam and for reference lines in Te-2 molecules in a vapor cell. The absolute frequencies were calibrated against a GPS stabilized Rb clock by means of an optical frequency comb. The 7s(2) S-1(0)(F = 1/2)-7s7p P-1(1)(F = 3/2) transition in Ra-225 was determined to be 621 042 124(2) MHz. The measurements provide input for designing efficient and robust laser cooling of Ra atoms in preparation of a search for a permanent electric dipole moment in Ra isotopes.

We investigate the effect on the nuclear matter equation of state (EOS) due to modification of meson and nucleon parameters in nuclear medium as a consequence of partial restoration of chiral symmetry. To get the EOS, we have used Brueckner-Bethe-Golstone formalism with Bonn-B potential as two-body interaction and QCD sum rule and Brown-Rho scaling prescriptions for modification of hadron parameters. We find that EOS is very much sensitive to the meson parameters. We can fit, with two body interaction alone, both the saturation density and the binding energy per nucleon.

With the final aim to explore the effect of the medium on hadron masses we study the reaction mechanism for the (p,p′ρ0) reaction on nuclei. We focus on the amplitudes which are dominated by the N*(1720)P13 resonance in intermediate state. This resonance has about 80% decay probability to Nρ channel. A nonrelativistic formalism is written for different amplitudes. The theoretical cross sections are presented for the 12 C target nucleus around 3 GeV beam energy. These results are found to be sensitive to the N* as well as ρ mass modifications in the medium. These two effects in the p′ spectrum can be separated experimentally as they are found to occur at different values of the p′ momentum. Because of the exploratory nature of this investigation, simple forms are used for the bound-state wave functions, and the continuum particles are approximated by plane waves.

A detailed study of the elementary p(p,p$'\pi^{+}$)n reaction is presented using the delta isobar model. In this model, in the first step one of the two protons in the initial state gets excited to $\Delta $. This, in the second step, decays into a nucleon and a pion. For the $pp \to N\Delta$ step the parametrized form of the DWBA t-matrix of Jain and Santra, which reproduces most of the available data on $pp \to n\Delta^{++}$, is used. The cross-sections studied include the outgoing proton momentum spectra in coincidence with the pion, the outgoing pion momentum spectra and the integrated total cross-section. We find that all the calculated numbers are in good agreement with the corresponding measured cross sections.

A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions., Comment: 11 pages, 6 figures

Using a value ofa 2=0.1±0.03 in a formalism which usesN c =3, we show that one can define an effectivea 2, which includes the contribution of nonfactorized effects, for color-suppressed decayB→ψK. We determine the magnitude of this effectivea 2, which is process-dependent and, in general, complex, in certain commonly used models of form factors. We analyze the color-suppressedB→ψK* branching ratio and longitudinal polarization and demonstrate that nonfactorization effects are needed to understand these data in certain commonly used models of form factors. We extend the analysis to color-suppressed decayB→ψ′K*, whereψ′=ψ(2S), and color-favored decay\(\bar B^0 \to D^{* + } \rho ^ - \) where we demonstrate that factorization scheme works well.

In six chosen scenarios for the $q^2$ dependence of the form factors involved in $D_s^+ \rightarrow \phi $ transition, we have determined the allowed domain of $x = A_2(0) / A_1(0)$ and $y = V(0)/A_1(0)$ from the experimentally measured ratios $R_{sl} = \Gamma(D_s^+ \rightarrow \phi l^+ \nu_l)/\Gamma(D_s^+ \rightarrow \phi \pi^+)$ and $R_h = \Gamma(D_s^+ \rightarrow \phi \rho^+)/\Gamma(D_s^+ \rightarrow \phi \pi^+)$ in a scheme that uses the $N_c =3$ value of the phenomenological parameter $a_1$ and includes nonfactorized contribution. We find that the experimentally measured values of $x$ and $y$ from semileptonic decays of $D_s^+$ favor solutions which have significant nonfactorized contribution, and, in particular, $R_{sl}$ favors solutions in scenarios where $A_1(q^2)$ is either flat or decreasing with $q^2$.

In order to probe the factorization hypothesis in the color-suppressed decays B\ensuremath{\rightarrow}\ensuremath{\psi}(2S)+K(K*) we have studied three ratios R\ensuremath{\equiv}B(B\ensuremath{\rightarrow}\ensuremath{\psi}K)/B(B\ensuremath{\rightarrow}\ensuremath{\psi}(2S)K), R\ensuremath{'}\ensuremath{\equiv}B(B\ensuremath{\rightarrow}\ensuremath{\psi}K*)/B(B\ensuremath{\rightarrow}\ensuremath{\psi}(2S)K*), and ${\mathrm{P}}_{\mathrm{L}}^{\ensuremath{'}}$\ensuremath{\equiv}${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{L}}$(B\ensuremath{\rightarrow}\ensuremath{\psi}(2S)K*)/\ensuremath{\Gamma}(B\ensuremath{\rightarrow}\ensuremath{\psi}(2S)K*) in several scenarios for the ${\mathrm{q}}^{2}$ dependence of the form factors involved. We find that measurements of R and R\ensuremath{'}, which exist, do not yield scenario-independent tests of factorization. However, the predicted range of ${\mathrm{P}}_{\mathrm{L}}^{\ensuremath{'}}$ in all scenarios lies in a narrow range, 0.50\ensuremath{\lesssim}${\mathrm{P}}_{\mathrm{L}}^{\ensuremath{'}}$\ensuremath{\leqslant}0.67, and could test factorization.

A measurement of the final state distribution of the B-8 beta decay, obtained by implanting a 8B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyvaskyla [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 ( 2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.

In this paper, we investigate light shifts of heavy alkaline earth elements barium (Ba) and radium (Ra), which are interesting for optical lattice clocks and for permanent electric dipole moment searches. Detailed knowledge is required in the design of efficient loading of atoms from a magneto-optical trap into an optical dipole trap, to facilitate Doppler cooling while trapping and to achieve longer lifetimes of the trapped atoms with reduced heating rates. The wavelength dependence of light shifts of the ns(2) (1)S(0) ground state, the nsnp (3)P(1) and ns(n - 1) d (1)D(2) excited states in barium (n = 6) and the n s(2) (1)S(0) ground state, the nsnp (3)P(1) and ns(n - 1) d (3)D(2) excited states in radium (n = 7) are calculated. Several magic wavelengths in the visible and infrared regions accessible with commercial lasers for optical dipole trapping of Ba and Ra are identified.

Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the $6d\phantom{\rule{0.16em}{0ex}}{{}^{2}\phantom{\rule{-0.16em}{0ex}}D}_{3/2}\phantom{\rule{0.16em}{0ex}}$--$7\phantom{\rule{-0.16em}{0ex}}p\phantom{\rule{0.16em}{0ex}}{{}^{2}\phantom{\rule{-0.16em}{0ex}}P}_{1/2}\phantom{\rule{0.16em}{0ex}}$ transition in ${}^{209\ensuremath{-}214}$Ra${}^{+}$, which are sensitive to the short-range part of the atomic wave functions, were measured. The results are essential experimental input for improving the precision of atomic structure calculations. This is indispensable for parity violation in Ra${}^{+}$ aiming at the determination of the weak mixing angle.

Rotational sandpile model (RSM) with quasi‐deterministic toppling rule is found to belong to different universality class than that of stochastic sandpile model (SSM). However, a continuous crossover from RSM to SSM can be achieved by introducing a quenched random rotational field in the model. The critical properties of RSM are studied as a function of concentration of quenched random rotational field.

Toppling number si of each sand column during an avalanche in a sandpile model defines a toppling surface. Several islands of different areas and sizes can be found by horizontal cut to the toppling surface at a given height. It is observed that there exists a critical relative height sc at which the number of islands and the fluctuation in the island size attain their maximum values. The area and size distributions of these islands at sc exhibit power law behavior with new critical exponents. The phenomenon is studied for the toppling surfaces obtained in different stochastic sandpile models.

As an important step toward an atomic parity violation experiment in one single trapped Ra${}^{+}$ ion, laser spectroscopy on short-lived $^{212,213,214}\mathrm{Ra}$${}^{+}$ ions was conducted. The isotope shift of the $6 {}^{2}{D}_{3/2}$-$7 {}^{2}{P}_{1/2} $and $6 {}^{2}{D}_{3/2}$-$7 {}^{2}{P}_{3/2} $transitions and the hyperfine structure constants of the $7 {}^{2}{P}_{1/2} $and $6 {}^{2}{D}_{3/2} $states in $^{213}\mathrm{Ra}$${}^{+}$ were measured, which provides a benchmark for the required atomic theory. A lower limit of $232(4)$ ms for $6 {}^{2}{D}_{5/2} $state lifetime was determined.

One of the greatest successes of the Standard Model of particle physics is the explanation of time-reversal violation (TRV) in heavy mesons. It also implies that TRV is immeasurably small in normal nuclear matter. However, unifying models beyond the Standard Model predict TRV to be within reach of measurement in nuclei and atoms, thus opening an important window to search for new physics. We will discuss two complementary experiments sensitive to TRV: Correlations in the beta-decay of (21)Na and the search for an electric dipole moment (EDM) in radium.

Considering that, in pp scattering, the pp → n Δ++ transition occurs mainly from the elastic channel, a t-matrix for this process was constructed by us earlier. This t-matrix describes the measured cross-sections on the p (p, n) Δ++ process very well from threshold to a few GeV. The transition potential in it is described by the one pion-exchange potential and the elastic scattering wave function through the "measured" elastic scattering amplitude. In this paper, we have parametrized this t-matrix so that it can be used for describing the (p, Δ++) reaction in nuclei. The parametrized t-matrix has been found to have a structure similar to one pion-exchange potential except that it has a softer form factor (Λ ≈ 650–800 MeV/c ) and it has a Migdal term (g′ ≈ 0.65) in the central term. The imaginary part of the t-matrix is weak. In the single scattering approximation this t-matrix describes the measured cross-sections on p(3 He , t) Δ++ and 6 Li (p, Δ++)6 He reactions very well. It is also found that with this t-matrix, the "projectile excitation" contribution to the reaction is small.

We have built a CsI(Tl) γ‐ray detector array for the NPDGamma experiment to search for a small parity‐violating directional asymmetry in the angular distribution of 2.2 MeV γ‐rays from the capture of polarized cold neutrons by protons with a sensitivity of several ppb. The weak pion‐nucleon coupling constant can be determined from this asymmetry. The small size of the asymmetry requires control of systematic errors at the ppb level, and the use of current‐mode γ‐ray detection with vacuum photo diodes and low‐noise solid‐state preamplifiers. The detectors were tested for noise performance, sensitivity to magnetic fields, pedestal stability, and cosmic background. False asymmetries due to gain changes and electronic pickup in the detector system were measured to be consistent with zero to an accuracy of 10−9 in a few hours. We show that the detector array operates at counting statistics and present asymmetry results for B4C , CCl4 , 27Al, Cu, and In. B4C , 27Al, Cu, and In are used throughout the experiment...

To study the effects of methylmethane sulphonate (CH3OSO2CH3), on the testicular tissue of the adult wild Indian house rat (Rattus rattus).A single intraperitoneal dose of methylmethane sulphonate (20 mg/kg) was administered and the effects were observed 2, 7, 15, 30 and 45 days later.Significant changes of the body, testes and accessory reproductive organs weight and a major depletion of the relative percentages of the spermatid and spermatozoa were noticed at 2, 7, 15 and 30 days after treatment. Gradual decrease in the seminiferous tubular area and Sertoli cell nuclear diameter was observed at 7, 15 and 30 days of treatment groups. The sperm population and sperm morphological abnormalities were also noticed in these three groups. Histochemical studies clearly revealed that the intensity of staining of the acid and alkaline phosphatase within 7 and 15 days after treatment was decreased, while the quantity of lipid materials was increased especially on the 2nd and 7th day after treatment. However, no significant changes were noticed in the delta5-3beta-HSDH and 17beta-HSDH enzymatic activity in the treated animals.These observations showed the antispermatogenic activity of methylmethane sulphonate on the testicular tissues and various accessory reproductive organs in the wild Indian house rat (Rattus rattus).

We have studied the excitation mechanism of ${d}^{*},$ a bound state of two deltas $(\ensuremath{\Delta}),$ in proton-deuteron collisions. In our model for the mechanism of ${d}^{*}$ excitation in this reaction, the incident proton interacts with both nucleons of the deuteron, exciting each one of them to the $\ensuremath{\Delta}$ state in sequence. The ${V}_{N\stackrel{\ensuremath{\rightarrow}}{N}N\ensuremath{\Delta}}$ transition potential is described by the one-pion exchange, parameters of which are fixed taking guidance from studies on $p\stackrel{\ensuremath{\rightarrow}}{p}N\ensuremath{\Delta}$ reaction. The results presented here are for angular distribution, mass distribution, t distribution, and the excitation function. We find that the position of the peak in the mass distribution is directly related to the strength of the $\ensuremath{\Delta}\ensuremath{-}\ensuremath{\Delta}$ binding potential. The excitation function peaks between 300- and 550-MeV beam energy for binding potentials between 500 and 350 MeV. The angular distribution peaks around $55\ifmmode^\circ\else\textdegree\fi{}\char21{}60\ifmmode^\circ\else\textdegree\fi{}.$