119490575
(Perturbed) Conformal Field Theory Applied to 2D Disordered Systems: An Introduction
These lectures will probably look too elementary to experts in disordered systems. It will perhaps be more appropriate as an introduction to this field for conformai field theorists.
2671755
Logarithmic Yangians in WZW Models
A new action of the Yangians in the WZW models is displayed. Its structure is generic and level-independent. This Yangian is the natural extension at the conformal point of the one unraveled in massive theories with current algebras. Hopefully, this new symmetry of WZW models will lead to a deeper understanding of the integrable structure of conformal field theories and their deformations.
15502559
Anomalous scaling in the N-point functions of a passive scalar.
A recent analysis of the 4-point correlation function of the passive scalar advected by a time-decorrelated random flow is extended to the N-point case. It is shown that all stationary-state inertial-range correlations are dominated by homogeneous zero modes of singular operators describing their evolution. We compute analytically the zero modes governing the N-point structure functions and the anomalous dimensions corresponding to them to the linear order in the scaling exponent of the 2-point function of the advecting velocity field. The implications of these calculations for the dissipation correlations are discussed.
17641456
Spin-Charge Separation and the Spin Quantum Hall Effect
We use quantum field theory methods to study the network model for the spin quantum hall transition. When the couplings are fine tuned in a certain way, the spin and charge degrees of freedom, corresponding to the su-percurrent algebras su(2) 0 and osp(2|2) −2 respectively, completely decouple. This simpler theory is exactly solvable and some critical exponents are computed and shown to agree with the recent predictions based on percolation. The general network model is shown to be in a different universality class by identifying the attractive direction of the renormalization group flow.
119018357
On Root Multiplicities of Some Hyperbolic Kac–Moody Algebras
Using the coset construction, we compute the root multiplicities at level-3 for some hyperbolic Kac–Moody algebras including the basic hyperbolic extension of A11 and E10.
120400467
An Introduction to Yangian Symmetries
We review some aspects of the quantum Yangians as symmetry algebras of two-dimensional quantum field theories. The plan of these notes is the following: 
 
1 
 
The classical Heisenberg model: 
 
 
 
 
 
 
 
 
 
Non-Abelian symmetries; 
 
 
The generators of the symmetries and the semi-classical Yangians; 
 
 
An alternative presentation of the semi-classical Yangians; 
 
 
Digression on Poisson-Lie groups. 
 
 
Non-Abelian symmetries and the quantum Yangians; 
 
 
The transfer matrix and an alternative presentation of the Yangians; 
 
 
Digression on the double Yangians. 
 
 
 
 
 
2 
 
The quantum Heisenberg chain: 
 
 
 
 
 
 
 
 
 
Non-Abelian symmetries and the quantum Yangians; 
 
 
The transfer matrix and an alternative presentation of the Yangians; 
 
 
Digression on the double Yangians.
41869150
Electron capture in an electron plasma wave
Abstract We study the influence of the radial electric field of a plasma wave on the accelerated electrons.
119860946
The laser wakefield acceleration experiment at Ecole Polytechnique
Abstract A laser wakefield electron acceleration experiment has been set-up at Ecole Polytechnique. An electron beam with 3 MeV total energy is injected in a plasma wave generated by laser wakefield using the new LULI CPA laser (400 fs [FWHM], I 17  W/cm 2 ). The first results show an effective acceleration of the order of 1 MeV, with a maximum when the electron density is close to the optimum value for which the laser pulse length is about half the plasma wavelength.
59451840
TPC in gamma-ray astronomy above pair-creation threshold
We examine the performance of a TPC as a -ray telescope above the pair-creation threshold. The contributions to the photon angular resolution are studied and their dependence on energy is obtained. The e ective area per detector unit mass for such a thin detector is the conversion mass attenuation coe cient. The di erential sensitivity for the detection of a point-like source is then derived. Finally, the measurement of track momentum from deflections due to multiple scattering is optimized. These analytical results are exemplified numerically for a few sets of detector parameters. TPCs show an impressive improvement in sensitivity with respect to existing pair-creation-based telescopes in the (MeV - GeV) energy range, even with the modest detector parameters of this study. In addition, gas TPCs allow an improvement in angular resolution of about one order of magnitude. High-energy astrophysics focuses on the study of com- plex objects such as active galactic nuclei (AGN), pulsars and gamma-ray bursts (GRB), the spectral energy distributions (SEDs) of which comprise contributions from a number of pro- cesses (1), including synchrotron emission, synchrotron self- Compton scattering (SSC), the inverse scattering of external thermal photons from the accretion disk (ESC), and 0 decays. These studies su er from the existence of gaps in the sensitivity of the available instruments, such as that between the Compton- scattering-based telescopes, that are mostly sensitive below 1 MeV, and the pair-based telescopes, that are mostly sensitive above 100 MeV. Pair-based telescopes also su er from a poor angular resolution at low energy, making the analysis of dense regions of the sky di cult. In this paper we present a characterization of the use of a thin detector as an active target for cosmic -ray detection in the pair-conversion regime, with the aim of improving the angular resolution and the sensitivity at low energy. The past missions and the presently operated Fermi/LAT and AGILE use thick de- tectors for which the photon conversion probability is close to unity and the e ective area A e is the product of the geomet- rical area of the detector A and of the reconstruction e ciency r: A e = A r. In a thin detector for which the conversion probability is small, the e ective area becomes proportional to the pair conversion mass attenuation coe cient H and to the detector mass M, A e = H M r. In a thick detector, the optimization of the aspect ratio height/surface is therefore criti- cal, while for a thin detector it does not a ect the e ective area to first order. Note that in a thick detector, the various pos- sible conversion processes are in competition with each other, and Compton scattering prior to- or in place of- pair conversion
59579040
Observation of Laser Wakefield Acceleration of Electrons
The acceleration of electrons injected in a plasma wave generated by the laser wakefield mechanism has been observed. A maximum energy gain of 1.6 MeV has been measured and the maximum longitudinal electric field is estimated to 1.5 GV/m. The experimental data agree with theoretical predictions when 3D effects are taken into account. The duration of the plasma wave inferred from the number of accelerated electrons is of the order of 1 ps
17481766
A Measurement of CP violating asymmetries in $B^0 \to$ f0(980) $K^0_{s}$ decays
We present preliminary measurements of the CP -violating asymmetries in the decay B → f0(980)(→ π+π−)K0 S . The results are obtained from a data sample of 209 × 10 Υ (4S) → BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a time-dependent maximum-likelihood fit we measure the mixing-induced CP violation parameter S = −0.95 −0.23 ± 0.10 and the direct CP violation parameter C = −0.24 ± 0.31 ± 0.15, where the first errors are statistical and the second systematic. Submitted to the 32 International Conference on High-Energy Physics, ICHEP 04, 16 August—22 August 2004, Beijing, China Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309 Work supported in part by Department of Energy contract DE-AC03-76SF00515. The BABAR Collaboration, B. Aubert, R. Barate, D. Boutigny, F. Couderc, J.-M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, V. Tisserand, A. Zghiche Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France A. Palano, A. Pompili Università di Bari, Dipartimento di Fisica and INFN, I-70126 Bari, Italy J. C. Chen, N. D. Qi, G. Rong, P. Wang, Y. S. Zhu Institute of High Energy Physics, Beijing 100039, China G. Eigen, I. Ofte, B. Stugu University of Bergen, Inst. of Physics, N-5007 Bergen, Norway G. S. Abrams, A. W. Borgland, A. B. Breon, D. N. Brown, J. Button-Shafer, R. N. Cahn, E. Charles, C. T. Day, M. S. Gill, A. V. Gritsan, Y. Groysman, R. G. Jacobsen, R. W. Kadel, J. Kadyk, L. T. Kerth, Yu. G. Kolomensky, G. Kukartsev, G. Lynch, L. M. Mir, P. J. Oddone, T. J. Orimoto, M. Pripstein, N. A. Roe, M. T. Ronan, V. G. Shelkov, W. A. Wenzel Lawrence Berkeley National Laboratory and University of California, Berkeley, CA 94720, USA M. Barrett, K. E. Ford, T. J. Harrison, A. J. Hart, C. M. Hawkes, S. E. Morgan, A. T. Watson University of Birmingham, Birmingham, B15 2TT, United Kingdom M. Fritsch, K. Goetzen, T. Held, H. Koch, B. Lewandowski, M. Pelizaeus, M. Steinke Ruhr Universität Bochum, Institut für Experimentalphysik 1, D-44780 Bochum, Germany J. T. Boyd, N. Chevalier, W. N. Cottingham, M. P. Kelly, T. E. Latham, F. F. Wilson University of Bristol, Bristol BS8 1TL, United Kingdom T. Cuhadar-Donszelmann, C. Hearty, N. S. Knecht, T. S. Mattison, J. A. McKenna, D. Thiessen University of British Columbia, Vancouver, BC, Canada V6T 1Z1 A. Khan, P. Kyberd, L. Teodorescu Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom A. E. Blinov, V. E. Blinov, V. P. Druzhinin, V. B. Golubev, V. N. Ivanchenko, E. A. Kravchenko, A. P. Onuchin, S. I. Serednyakov, Yu. I. Skovpen, E. P. Solodov, A. N. Yushkov Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia D. Best, M. Bruinsma, M. Chao, I. Eschrich, D. Kirkby, A. J. Lankford, M. Mandelkern, R. K. Mommsen, W. Roethel, D. P. Stoker University of California at Irvine, Irvine, CA 92697, USA C. Buchanan, B. L. Hartfiel University of California at Los Angeles, Los Angeles, CA 90024, USA S. D. Foulkes, J. W. Gary, B. C. Shen, K. Wang University of California at Riverside, Riverside, CA 92521, USA