Electric properties of the Beryllium-11 system in Halo EFT

We compute E1 transitions and electric radii in the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the leading-order parameters of the EFT from measured data on the 1/²⁺ and 1/²⁻ levels in ¹¹Be and the B(E1) strength for the transition between them. We then obtain predictions for the B(E1) strength for Coulomb dissociation of the ¹¹Be nucleus to the continuum. We also compute the charge radii of the 1/²⁺ and 1/²⁻ states. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also discuss how next-to-leading-order (NLO) corrections involving both s-wave and p-wave ¹⁰Be-neutron interactions affect our results, and display the NLO predictions for quantities which are free of additional short-distance operators at this order. Information on neutron-¹⁰Be scattering in the relevant channels is inferred.     

Theoretical study of Si+(2PJ)–RG complexes and transport of Si+(2PJ) in RG (RG = He–Ar)

We calculate accurate interatomic potentials for the interaction of a singly charged silicon cation with a rare gas atom of helium, neon or argon. We employ the RCCSD(T) method, and basis sets of quadruple-ζ and quintuple-ζ quality; each point is counterpoise-corrected and extrapolated to the basis set limit. We consider the lowest electronic state of the silicon atomic cation, Si⁺(²P), and calculate the interatomic potentials for the terms that arise from this: ²Π and ²Σ⁺. We additionally calculate the interatomic potentials for the respective spin-orbit levels, and examine the effect on the spectroscopic parameters; we also derive effective ionic radii for C⁺ and Si⁺. Finally, we employ each set of potentials to calculate transport coefficients, and compare these to available data for Si⁺ in He.     

Generation and search of axion-like light particle using intense crystalline field

Intense electric field ∼¹⁰¹⁰-¹⁰¹¹ V/cm in crystal has been known for a long time and has wide applications. We study the conversion of axion-like light particle and photon in the intense electric field in crystal. We find that the conversion of axion-like particle and photon happens for energy larger than keV range. We propose search of axion-like light particle using the intense crystalline field. We discuss the solar axion search experiment and a variety of shining-through-wall experiment using crystalline field. Due to the intense crystalline field which corresponds to magnetic field ∼¹⁰⁴-¹⁰⁵ Tesla these experiments are very interesting. In particular these experiments can probe the mass range of axion-like particle from eV to keV.     

Glueball masses and symmetry restoration inSU(3) lattice gauge theory: A high statistics Monte Carlo study

We calculate 0⁺⁺, 2⁺⁺ and 1^?+ correlation functions for a wide range of momenta in a high statisticsSU(3) study on an 8⁴ lattice: 28,000 sweeps at β=5.7 and 18,000 at β=5.9. We obtain an accurate confirmation of the restoration of the continuum relativistic dispersion relation,E ²=p ²+m ², and of rotational invariance. We obtain accurate 2⁺⁺ mass estimates up to two lattice spacings, and confirm consistency with asymptotic scaling. For the 1^?+ the results are much poorer and we can only present some very crude mass estimates. We compare our 0⁺⁺ data to our previous calculations with a source, and make some statements about the relative efficiencies of source and variational calculations in this range of couplings.     

A useful quantity for studying jet structure in e+e− annihilation

We propose a new variable for studying the deviation from perfect two-jet structure in e⁺e^? annihilation. This involves only charged particles in the final state. We calculate this in QCD. We also discover a strong-interaction independent prediction in e⁺e^? annihilation.     

Heavy Majorana neutrinos in e + e − → W + W−

In this paper we investigate the effects of heavy Majorana neutrinos in the reaction e ⁺ e ^? → W ⁺ W ^?. We consider neutrino masses in the 1–10 TeV region. We show that at LEP II and NLC energies it is possible to use this processes to verify indirect evidence of heavy neutral particles with mixing angles of the order sin² α = 0.01. We discuss the unitarity restrictions that can be obtained for vector singlet and fermion-mirror-fermion models.     

Relevance of thermally populated first excited state of 44Ti to the abundance problem of cassiopiea A: A model study

We examine the possible role of electron-capture on the thermally populated first 2⁺ excited state of ⁴⁴Ti in hot astrophysical environments pertaining to post explosive nucleosynthesis supernova debris. We find in a simple schematic model that the astrophysical weak interaction rate for electron-capture decay of ⁴⁴Ti can depend considerably on temperature and hence on time. We propose a time varying decay rate for the evolving supernova debris and demonstrate its consequence for the ⁴⁴Ti mass yield of the supernova Cas A, observed through the measured 1.157 MeV γ-ray flux from the electron-capture decay of ⁴⁴Ti.     

Three-body structure of low-lying <Superscript>18</Superscript>Ne states

We investigate to what extent ¹⁸Ne can be descibed as a three-body system made of an inert ¹⁶O core and two protons. We compare to experimental data and occasionally to shell model results. We obtain three-body wave functions with the hyperspherical adiabatic expansion method. We study the spectrum of ¹⁸Ne , the structure of the different states and the predominant transition strengths. Two 0⁺, two 2⁺, and one 4⁺ bound states are found where they are all known experimentally. Also one 3⁺ close to threshold is found and several negative-parity states, 1^-, 3^-, 0^-, 2^-, most of them bound with respect to the ¹⁶O excited 3^- state. The structures are extracted as partial-wave components, as spatial sizes of matter and charge, and as probability distributions. Electromagnetic decay rates are calculated for these states. The dominating decay mode for the bound states is E2 and occasionally also M1 .     

Phenomenological applications of<Emphasis Type="Italic">k</Emphasis><Subscript>T</Subscript>factorization

We discuss applications of the perturbative QCD approach in the exclusive non-leptonic two-bodyB-meson decays. We briefly review its ingredients and some important theoretical issues on the factorization approach. PQCD results are compatible with present experimental data for charmless B-meson decays. We predict the possibility of large direct CP asymmetry in B⁰ → π⁺π⁻ (23 +7%) and B⁰ →K ⁺π⁻ (− 17 ± 5%). We also investigate the branching ratios, CP asymmetry and isospin symmetry breaking in radiativeB →(K*/ρ)γ decays.     

Scattering Length for Helium Atom-Diatom Collision

We present results on the scattering lengths of ⁴He-⁴He₂ and ³He-⁴He₂ collisions. We also study the consequence of varying the coupling constant of the atom-atom interaction.     

Can one test technicolour?

We estimate the couplings to ordinary particles of the lightest bound states in technicolour theories and discuss the resulting phenomenology. We compute their couplings to light gauge bosons through axial anomalies and also estimate their non-anomalous couplings at low energies. We estimate their couplings to fermions under the general simplifying assumption that each fermion acquires its mass from a unique technifermion condensate (“monophagy”), in which case they are naturally flavour conserving and relatively well-defined. We find that the classic Higgs search experiments (ttoponium → H⁰ + γ, e⁺e^? → H⁺H^?, e⁺e^? → Z⁰ + H⁰) enable one to make a decisive discrimination between elementary and composite models of spontaneous symmetry breaking. We also emphasize the interest of improving experimental limits on K_L⁰ → μe in the context of dynamical symmetry breaking models.     

Higher order QCD effects in inclusive annihilation and deep inelastic scattering

We present a parton model interpretation of the predictions of quantum chromodynamics in the process e⁺e^?→hadron + anything. We give thecomplete list of parameters needed for the study of the scaling violations of fragmentation functions up to the next-to-leading logarithmic approximation. This includes flavour non-singlet and flavour singlet anomalous dimensions up to order α² and coefficient functions up to order α. We also present results for the deep inelastic scattering e^?h→e^? + anything. We find that in e⁺e^? annihilation the ratio of scaling violations of second order to first order is in general bigger than the corresponding ratio for deep inelastic scattering. The Gribov-Lipatov relation is thus violated in second order. We also find that a modified Drell-Yan analytic continuation relation holds between the deep inelastic and annihilation structure functions for quarks and gluons. In x space we give detailed numerical evaluation of the QCD effects for non-singlet and singlet densities, in the space-like and time-like regions.     

Phase shift analysis of the <Superscript>6</Superscript>He+<Superscript>208</Superscript>Pb and the <Superscript>6</Superscript>He+<Superscript>197</Superscript>Au systems

We present the elastic scattering of the ⁶He+²⁰⁸Pb and the ⁶He+¹⁹⁷Au systems at the laboratory energy of E _lab=27 MeV within the framework of the McIntyre parametrization, and systematically investigate χ ²/N analysis of both systems to obtain an excellent agreement between the theoretical results and the experimental data. We find large diffusivity parameters indicating long range absorption mechanisms. We also show that both systems lack both the nuclear and the Coulomb rainbow scattering for obtained S-matrix parameters.     

Quantum-degenerate gases of Ytterbium atoms

Evaporative cooling of ultracold Yb atoms near the quantum-degenerate regime was experimentally studied. Three bosons of ¹⁷⁰Yb, ¹⁷²Yb, ¹⁷⁶Yb and two fermions of ¹⁷¹Yb and ¹⁷³Yb were evaporatively cooled in a crossed far-off resonant trap (FORT). We observed that ¹⁷⁰Yb and ¹⁷²Yb were not concentrated into the crossed region. We found that, in the cases of ¹⁷⁶Yb atoms, atoms were concentrated well into the crossed region. The following evaporative cooling in the crossed region, however, did not work well. We performed the simultaneous trapping and sympathetic cooling in the crossed FORT by use of ¹⁷²Yb-174Yb, ¹⁷⁴Yb-¹⁷⁶Yb, ¹⁷²Yb-¹⁷⁶Yb, and ¹⁷¹Yb-¹⁷⁴Yb pairs. We observed that evaporative cooling worked well. This result shows that we succeeded in the enhancement of the atom collision rate. Especially, by use of ¹⁷⁴Yb-¹⁷⁶Yb mixture, we obtained cold ¹⁷⁶Yb whose phase space density was 0.02. We observed a large atom loss, which limited the further sympathetic evaporative cooling. We also evaporatively cooled ¹⁷⁴Yb in a 1D optical lattice. Evaporative cooling worked very well because the atoms were initially trapped at a high density. After evaporative cooling, we obtained very cold atoms, and T/T _F was estimated to be 1.2.     

Linear α-chain states in nuclei

We present results for the energies of the linear α-chain states in several light nuclei,¹²C,¹⁶O,²⁰Ne and²⁴Mg, using the Skyrme Hartree-Fock method. We discuss mainly the SKM^* results but other interactions are also considered for comparison.     

Theoretical response to the discovery of deeply bound pionic states in208Pb(d,3He) reactions

Recently, deeply bound pionic states were found experimentally in (d,³He) reactions on²⁰⁸Pb. They found an isolated peak structure in the bound region below the pion production threshold. We study theoretically these excitation functions in (d,³He) reactions on²⁰⁸Pb at T _d =600 MeV. We found very good agreement with the (d,³He) excitation functions and could identify the underlying structures of the pionic states. We study the energy dependence of the (d,³He) reactions and the change of the excitation functions with the incident energy.     

First observation of F

We measured the excitation function for ¹³O + p elastic scattering to obtain data on the unknown ¹⁴F nucleus. The ground state and several low-lying excited states in ¹⁴F were observed and spin/parity assignments were made. ¹⁴F appears to be much less unstable than was predicted. We compare theoretical predictions for the ¹⁴F level scheme with the experimental results.     

Factorization at higher twist in hadron-hadron scattering

We study one-loop soft gluon effects in a scalar quark QCD model of the Drell-Yan process. We find that factorization of the type suggested by Politzer holds at order m²/s, but fails at order m⁴/s². We suggest that this pattern holds to higher orders, and that the non-factoring terms are not suppressed by form factors. We compute the non-factoring contributions, and give a classical interpretation of our results.     

ππ partial waves from 0.6 to 1.8 GeV

We use high statistics π^?p → π^?π⁺n data at 17.2 GeV/c to calculate the ππ partial-wave amplitudes in the energy range 0.6<M_ππ< 1.8 GeV. We perform both energy-independent and energy-dependent analyses using Barrelet zero techniques. We find four possible solutions for the partial waves, each containing the leading ?, f, g resonances but with very different lower partial waves. Two solutions contain a ?' resonance in the g region, but it is not possible to establish the existence of other possible broad daughter resonances. We show that accurate measurements of π^?p → π⁰π⁰n should select the physical solution.     

Dependence on collision energy of the stereodynamical properties of the 18O + 32O2 exchange reaction

We report a quantum stereodynamical study of the ¹⁸O + ¹⁶O¹⁶O(v = 0, j = 1) → ¹⁸O¹⁶O(v′ = 0, j′) + ¹⁶O oxygen exchange reaction at four different collision energies. We calculated the polarisation moments and generated stereodynamical portraits related to the key vectors involved in this collision process. Ozone complex-forming approaches of reactants are then deduced. The results indicate that different approaches are possible but strongly depend on the collision energy and other parameters of the collision. We also conclude that the reaction globally tends to favour a perpendicular approach with increasing energy.