Contrasting continuous emission versus freeze-out via HDT

The effect of continuous emission hypothesis on the two-pion Bose-Einstein correlation is discussed and compared with the corresponding results based on the usual freeze-out ansatz. Sizable differences in the correlation function are observed when comparing these two scenarios of the decoupling process. They could lead to entirely different interpretation of properties of the hot matter formed in high-energy heavy-ion collisions.

Combined D0 measurements constraining the CP-violating phase and width difference in the B-s(0) system

We combine the D0 measurement of the width difference between the light and heavy B-s(0) mass eigenstates and of the CP-violating mixing phase determined from the time-dependent angular distributions in the B-s(0)-> J/psi phi decays along with the charge asymmetry in semileptonic decays also measured with the D0 detector. With the additional constraint from the world average of the flavor-specific B-s(0) lifetime, we obtain Delta Gamma(s)equivalent to(Gamma(L)-Gamma(H))=0.13 +/- 0.09 ps(-1) and vertical bar phi(s)vertical bar=0.70(-0.47)(+0.39) or Delta Gamma(s)=-0.13 +/- 0.09 ps(-1) and vertical bar phi(s)vertical bar=2.44(-0.39)(+0.47). The data sample corresponds to an integrated luminosity of 1.1 fb(-1) accumulated with the D0 detector at the Fermilab Tevatron Collider.

Evolution of magnetic field and spin period in accreting neutron stars

Based on the accretion-induced magnetic field decay model, in which a frozen field and an incompressible fluid are assumed, we obtain the following results: (1) an analytic relation between the magnetic field and spin period, if the fastness parameter of the accretion disk is neglected (The evolutionary tracks of accreting neutron stars in the P-B diagram in our model are different from the equilibrium period lines when the influence of the fastness parameter is taken into account.); (2) the theoretical minimum spin period of an accreting neutron star is max(1.1ms (DeltaM/M(circle dot))(-1)R(6)(-5/14) I(45)(M/M(circle dot))(-1/2),1.1ms (M/M(circle dot))(-1/2) R(6)(17/14)), independent of the accretion rate (X-ray luminosity) but dependent on the total accretion mass, DeltaM; however, the minimum magnetic field depends on the accretion rate; (3) the magnetic field strength decreases faster with time than does the period.

On the HBO mechanism of X-ray neutron star

We ascribe the 15-60 Hz Quasi Periodic Oscillation (QPO) to the periastron precession frequency of the orbiting accreted matter at the boundary of magnetosphere-disk of Xray neutron star (NS). Considering the relativistic motion mechanism for the kHz QPO, that the radii of the inner disk and magnetosphere-disk of NS are correlated with each other by a factor is assumed. The obtained conclusions include: all QPO frequencies increase with increasing the accretion rate. The theoretical relations between 15-60 Hz QPO (HBO) frequency and the twin kHz QPOs are similar to the measured empirical formula. Further, the better fitted NS mass by the proposed model is about 1.9 solar masses for the detected LMXBs.

Structure of large two-neutron halos in light exotic nuclei

The structure of three-body halo nuclei formed by two neutrons and a core (nnc) is studied using zero-range interactions. The halo wave function can be completely parameterized only by the s-wave scattering lengths and two-neutron separation energy. The sizes and the neutron-neutron correlation function of Li-11 and Be-14 are calculated and compared to experimental data. A general classification scheme for three-body halos with two identical particles is discussed as well as the critical conditions to allow excited Efimov states.

Neutron-neutron correlation in the halo dissociation of light exotic nuclei

We present model results for the two-halo-neutron correlation functions, C-nn, for the dissociation process of light exotic nuclei modelled as two neutrons and a core. A minimum is predicted for C-nn as a function of the relative momentum of the two neutrons, p(nn), due to the coherence of the neutrons in the halo and final state interaction. Studying the systems Be-14, Li-11, and He-6 within this model, we show that the numerical asymptotic limit, C-nn-> 1, occurs only for p(nn)greater than or similar to 400 MeV/c, while such limit is reached for much lower values of p(nn) in an independent particle model as the one used in the analysis of recent experimental data. Our model is consistent with data once the experimental correlation function is appropriately normalized.

Constraints on two-neutron separation energy in the Borromean C-22 nucleus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Trajectory of neutron-neutron-C-18 excited three-body state

The trajectory of the first excited Efimov state is investigated by using a renormalized zero-range three-body model for a system with two bound and one virtual two-body subsystems. The approach is applied to n-n-C-18, where the n-n virtual energy and the three-body ground state are kept fixed. It is shown that such three-body excited state goes from a bound to a virtual state when the n-C-18 binding energy is increased. Results obtained for the n-C-19 elastic cross-section at low energies also show dominance of an S-matrix pole corresponding to a bound or virtual Efimov state. It is also presented a brief discussion of these findings in the context of ultracold atom physics with tunable scattering lengths. (C) 2008 Elsevier B.V. All rights reserved.

Mass and width of a composite Higgs boson

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

EXOTIC CARBON SYSTEMS IN TWO-NEUTRON HALO THREE-BODY MODELS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Neutron-C-19 scattering near an Efimov state

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Direct Measurement of the W Boson Width

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of the Width of the Top Quark

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Improved determination of the width of the top quark

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morphology and Blue Photoluminescence Emission of PbMoO4 Processed in Conventional Hydrothermal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)