[en] In this work quarkonia states are described as eigenstates of a Hamiltonian that allows the coupling of QQ to a pair of heavy-light mesons (Qq, Qq). The decay amplitude of QQ into Qq, Qq is derived using the flux tube breaking model. The coupled channel mixing effect is calculated both relativistically and nonrelativistically. The results shows that the relativistic effect in the coupled channel mixing calculation is very important. The relativistic effect makes the mass shifts of all states much larger than the nonrelativistic counterpart and relativistic treatment gives a results which is in better agreement with the experiment data. Relativistic and coupled channel mixing effects are taken into account to estimate the one photon radiative M1 and E1 transitions. The GRR potential model is used for this calculation. The decay rates of M1 transitions involving D-states are very small except the transition 1¹D₂ → 1³S₁ + γ which is about 2.13 kev. The S → S M1 transition rates are in agreement with or close to the experiment data after drop the term due to the scalar interaction. The result in chapter 5 shows that both the relativistic and coupled channel mixing corrections have large effect on the E1 transitions. For some E1 transitions with too large relativistic corrections the higher order correction are needed. The leptonic decay widths of D-states are discussed in section 5.6

No abstract available

[en] The authors calculate the E2 and M3 transition amplitudes for the decay of the singlet D sate to the triplet S state of charmonium using a nonsingular quarkonium potential model. They find that the E2 and M3 amplitudes are much larger than the M1 amplitude, and the results are very different from that calculated by using a potential which has singular terms

[en] The author calculates the hyperfine splitting between the singlet and the center of gravity of the triplet P states of charmonium using the perturbative QCD hyperfine interaction to order α_s, in the improved quasistatic aproximation of Gupta. The author finds that in the improved quasistatic approximation, there is nonzero contribution to the hyperfine splitting of the P states even to order α_s and in fact this is the dominant contribution. The author numerically evaluates this hyperfine splitting both in first order perturbation theory and using the nonperturbative variational method in the nonsingular potential model of Gupta, Repko and Suchyta. There is a big difference between the perturbative and nonperturbative results for charmonium

[en] ALICE (A Large Ion Collider Experiment) is the experiment dedicated to the study of heavy-ion collisions at the LHC. ALICE also takes part in the LHC proton- proton program which is of great interest for testing perturbative QCD calculations at unprecedented low Bjorken-x values and for providing the necessary baseline for nucleus-nucleus and proton-nucleus collisions. ALICE will also collect, in the beginning of 2013, p-Pb/Pb-p collisions in order to investigate cold nuclear matter effects. ALICE measures quarkonia and open heavy flavours with (di)-electrons, (di)-muons and through the hadronic channels. This thesis work is devoted to the study of open heavy flavours in proton-proton and Pb-Pb collisions via single muons with the ALICE forward muon spectrometer. The document is organized as follows. The first chapter consists in a general introduction on heavy-ion collisions and QCD phase transitions. Chapter 2 summarizes the motivations for the study of open heavy flavours in nucleon-nucleon, nucleon-nucleus and nucleus-nucleus collisions. Chapter 3 gives an overview of the ALICE experiment with a detailed description of the forward muon spectrometer. Chapter 4 gives a short summary of the ALICE online and offline systems. Then the analysis framework (for data and simulations) and in particular the software developed for the study of open heavy flavours is detailed. Chapter 5 summarizes the performance of the ALICE muon spectrometer for the study of the production of open heavy flavours in pp collisions via single muons and dimuons. Chapters 6 to 9 are dedicated to data analysis. Chapter 6 deals with the analysis of first pp collisions at 900 GeV. The main aim was the understanding of the response of the apparatus. Chapter 7 presents the measurement of the production of heavy flavour decay muons in pp collisions at √(s) = 7 TeV. The analysis strategy is described: event and track selection, background subtraction (mainly the contribution of muons from primary pion and kaon decays), corrections, normalization and investigation of the systematic uncertainties. Chapter 8 addresses the measurement of heavy flavour decay muon production in Pb-Pb collisions at √(s_NN) = 2.76 TeV collected in 2010. The analysis strategy is presented

[en] We discuss the structure of point-fuzzy number set F (R), 1) Defining a non-negative function Rho in F (R) and proving that Rho satisfies the Hausdorff postulates, thus (F(R), Rho) constituting fuzzy metric space. 2) Defining the concepts such as limit, Fuzzy-Cauchy sequence and its convergence in (F(R), Rho), and proving any of F-Cauchy sequence in (F(R), Rho) convergent, thereby finding out (F(R), Rho) complete, that is, complete metric space

[en] The atomistic simulation techniques are used to study La_1-xCa_xMnO₃. Various possible structures of La_0.333Ca_0.667MnO₃ are studied. It is found that the Wigner-crystal model is more energetically favorable than the Bi-stripe model. It is also found that Ca doping site has substantial effect on structure of La_0.5Ca_0.5MnO₃. Two most energetically favorable La_0.5Ca_0.5MnO₃ structures are found. They have an ordered arrangement of La³⁺ and Ca²⁺ ions and different arrangements of Mn³⁺ and Mn⁴⁺ ions, which may affect the charge, orbital and magnetic ordering in La_0.5Ca_0.5MnO₃. It is also found that the ordered distribution of Ca is energetically more favorable than the random distribution of Ca in La_0.5Ca_0.5MnO₃ at low temperature

[en] A design of the injection low energy transport line for the proposed NSLS UV-FEL is presented. The main concern is to control the beam transverse emittance dilution due to space charge, energy spread and non-linear forces introduced by magnetic elements. The design considerations to optimize the transport line are discussed including the deleterious effects of space charge and energy spread as modeled by the particle code PARMELA. The results from PARMELA are analyzed, and the concept of slice emittance is used to examine the causes of emittance growth

[en] A large positive magnetoresistance (MR) has been found in micro-sized Ni_x-C_1-x granular composites. Ni₂₀-C₈₀ composite has the largest MR of 44.1% and 138.5% at room temperature and 5 K under a magnetic field of 5 T, respectively. The magnetic field dependence of the MR can be approximately described as MR∝Bⁿ, and the value of n is determined by the Ni concentration and temperature, ranging from 1/4 to 3/2. It is found that every Ni_x-C_1-x specimen under study has a linear field dependence of the positive MR at a special temperature. The possible mechanism for the positive MR of Ni_x-C_1-x composites has been discussed

[en] This issue is the collection of the documents presented at the title meeting. (J.P.N.)