Propagation of Fast Partons in the Nuclear Medium

The color dipole approach has been applied in the target rest frame to address the issues of transverse momentum broadening and energy loss of a fast quark propagating in the nuclear medium. A recent application of the theory to the FermiLab E772/E866 experimental data, determining the rate of energy loss of a quark propagating in the medium to be 2 to 3 GeV/fm, will be reviewed. Calculations for the transverse momentum distribution will be presented, and the results will be compared to the E866 data. The theory will be shown to compare favorably to the data, and these results will be shown to suggest that the momentum broadening of a quark is about twice the generally accepted size.Comment: 6 pages, 4 figures, Invited talk given at 4th International Conference on Perspectives in Hadronic Physic

Realistic Neutrino Masses from Multi-brane Extensions of the Randall-Sundrum Model?

Scenarios based on the existence of large or warped (Randall-Sundrum model) extra dimensions have been proposed for addressing the long standing puzzle of gauge hierarchy problem. Within the contexts of both those scenarios, a novel and original type of mechanism generating small (Dirac) neutrino masses, which relies on the presence of additional right-handed neutrinos that propagate in the bulk, has arisen. The main objective of the present study is to determine whether this geometrical mechanism can produce reasonable neutrino masses also in the interesting multi-brane extensions of the Randall-Sundrum model. We demonstrate that, in some multi-brane extensions, neutrino masses in agreement with all relevant experimental bounds can indeed be generated but at the price of a constraint (stronger than the existing ones) on the bulk geometry, and that the other multi-brane models even conflict with those experimental bounds.Comment: 29 pages, 3 figures, Latex file. References added, study extende

Evidence for an Excess of Soft Photons in Hadronic Decays of Z^0

Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the kinematic range 0.2 < E_gamma < 1 GeV and transverse momentum with respect to the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.Comment: 37 pages, 9 figures, Accepted by Eur. Phys. J.

Radial solitons in armchair carbon nanotubes

Radial solitons are investigated in armchair carbon nanotubes using a generalized Lennard-Jones potential. The radial solitons are found in terms of moving kink defects whose velocity obeys a dispersion relation. Effects of lattice discreteness on the shape of kink defects are examined by estimating the Peierls stress. Results suggest that the typical size for an unpinned kink phase is of the order of a lattice spacing.Comment: 11 pages, 3(eps) figure

Sr_14Cu_24O_41Sr\_{14}Cu\_{24}O\_{41} : a complete model for the chain sub-system

A second neighbor $t-J+V$ model for the chain subsystem of the $Sr\_{14}Cu\_{24}O\_{41}$ has been extracted from ab-initio calculations. This model does not use periodic approximation but describes the entire chain through the use of the four-dimensional crystallographic description. Second neighbors interactions are found to be of same order than the first neighbors ones. The computed values of the second neighbors magnetic interaction are coherent with experimental estimations of the intra-dimer magnetic interactions, even if slightly smaller. The reasons of this underestimation are detailed. The computed model allowed us to understand the origin of the chain dimerisation and predicts correctly the relative occurrence of dimers and free spins. The orbitals respectively supporting the magnetic electrons and the holes have been found to be essentially supported by the copper 3d orbitals (spins) and the surrounding oxygen $2p$ orbitals (holes), thus giving a strong footing to the existence of Zhang-Rice singlets

Factorization Breaking in Diffractive Dijet Photoproduction

We have calculated the diffractive dijet cross section in low-Q^2 ep scattering in the HERA regime. The results of the calculation in LO and NLO are compared to recent experimental data of the H1 collaboration. We find that in LO the calculated cross sections are in reasonable agreement with the experimental results. In NLO, however, some of the cross sections disagree, showing that factorization breaking occurs in that order. By suppressing the resolved contribution by a factor of approximately three, good agreement with all the data is found. The size of the factorization breaking effects in diffractive dijet photoproduction agrees well with absorptive model predictions.Comment: 13 pages, 8 figure

Strong Coulomb effects in hole-doped Heisenberg chains

Substances such as the ``telephone number compound'' Sr14Cu24O41 are intrinsically hole-doped. The involved interplay of spin and charge dynamics is a challenge for theory. In this article we propose to describe hole-doped Heisenberg spin rings by means of complete numerical diagonalization of a Heisenberg Hamiltonian that depends parametrically on hole positions and includes the screened Coulomb interaction among the holes. It is demonstrated that key observables like magnetic susceptibility, specific heat, and inelastic neutron scattering cross section depend sensitively on the dielectric constant of the screened Coulomb potential.Comment: 5 pages, 6 figures, to be published in Eur. Phys. J.

Application of the Two-Scale Model to the HERMES Data on Nuclear Attenuation

The Two-Scale Model and its improved version were used to perform the fit to the HERMES data for $\nu$ (the virtual photon energy) and z (the fraction of $\nu$ carried by hadron) dependencies of nuclear multiplicity ratios for $\pi^+$ and $\pi^-$ mesons electro-produced on two nuclear targets ($^{14}$N and $^{84}$Kr). The quantitative criterium $\chi ^2$ was used for the first time to analyse the results of the model fit to the nuclear multiplicity ratios data. The two-parameter's fit gives satisfactory agreement with the HERMES data. Best values of the parameters were then used to calculate the $\nu$- and $z$ - dependencies of nuclear attenuation for $\pi^0$, K$^+$, K$^-$ and $\bar{p}$ produced on $^{84}$Kr target, and also make a predictions for $\nu$, z and the Q$^2$ (the photon virtuality) - dependencies of nuclear attenuation data for those identified hadrons and nuclea, that will be published by HERMES

PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE TWO STAY TWO STRAY UNTUK MENINGKATKAN HASIL BELAJAR SISWA PADA MATA PELAJARAN PENDIDIKAN KEWARGANEGARAAN (Penelitian Tindakan Kelas pada materi Pancasila sebagai dasar dan Ideologi Negara di kelas VIII-D SMP Pasundan 2 Bandung)

Penelitian ini bertujuan untuk mengetahui peningkatan hasil belajar pada materi pancasila sebagai dasar dan ideologi negara pada siswa kelas VIII - D SMP Pasundan 2 Bandung dengan menggunakan model pembelajaran Kooperatif tipe Two Stay Two Stray . Lokasi pen elitian ini adalah di SMP Pasundan 2 Bandung Kota Bandung Tahun Pelajaran 2016/2017. Objek penelitian ini adalah si swa kelas VIII - D yang berjumlah 33 orang . Penelitian ini menggunakan metode penelitian tindakan kelas, yang terdiri dua siklus, yakni siklus I dan siklus II dengan menerapkan model pembelajaran Kooperatif tipe Two Stay Two Stray , pada siklus I peneliti menerangkan materi dengan model pembelajaran yang sama pada mata pe lajaran Pendidikan Kewarganegaraan serta mengadakan post test. dan di siklus II juga peneliti menerangkan materi dengan menggunakan model pembelajaran kooperatif tipe Two Stay Two Stray d an diakhiri dengan pemberian post test dengan instrumen penelitian lembar pengamatan test hasil belajar. Hasil penelitian pad a hasil post test pa da siklus I sebesar 68,48% dimana 14 orang siswa yang tuntas dan 19 orang siswa belum tuntas. Pada siklus II hasil post test sebesar 90, 0 9 % dimana 33 orang siswa tuntas semua. Dengan demikian dapat diambil kesimpulan bahwa dengan menggunakan model pembelajaran Kooperatif tipe Two Stay Two Stray dapat meningkatkan hasil belaja r siswa pada mata pelajaran Pendidikan Kewarganegaraan. Kata Kunci : Kooperatif tipe two stay two stray , hasil belajar, PK

Circular 59

This list of recommended annual flower varieties includes information on several hundred annual flower cultivars. The recommended varieties were selected from flowers grown in 1985 and 1986 at the Agricultural and Forestry Experiment Station Farm at the University of Alaska- Fairbanks. While this is by no means a complete listing of varieties suitable for Interior gardens, it does reflect many years of experience in annual flower production at the AFES farm. The methods used to evaluate the flowers and definitions for terms used in the listing can be found under Data Collection.Introduction -- Methods: Bedding Plant Production, Field Conditions, Weather Conditions, Data Collection -- List of Recommended Annual Flower Varieties -- Photo Section -- Appendix 1. Seeding Information -- Appendix 2. Flower Varieties by Color: Blue, Purple; Red, Pink; Red, Pink and White Mixes; White; Yellow, Orange, Gold; Mixed Colors; Foliage Only -- Appendix 3. Bloom Period: Early Season, All Season, Midseason, Late Season, Frost Resistant -- Appendix 4. Plant Heights: Short Varieties, Medium Varieties, Tall Varieties -- Appendix 5. Flowers for Special Purposes: Hanging Baskets, Light Shade, Walls, Rock Garden, Background -- Appendix 6. Seed Source