119542112
Hall Conductivity for Charged Strings and Modified Spectrum-Generating Algebra
When open strings end with a charge q on a D2-brane, which involves constant background magnetic field B perpendicular to the brane, we calculate the Hall conductivity for these charged strings. We also construct the corresponding spectrum-generating algebra, which assures that our system is ghost-free under some conditions.
122739517
Electromagnetic Properties of the Kaluza-Klein String
On calcule le g-facteur magnetique pour la corde dans la theorie de Kaluza-Klein de l'espace-temps a 5 dimensions et on trouve une formule generale des moments magnetiques avec le g-facteur universel de g(J)=1 pour tous les etats de corde
121289650
Schwarzian Connections in the Krichever-Novikov Algebra
In the local operator approach to higher-genus Riemann surface we point out an importance of
9105602
Charged superstrings in background gauge fields and spectrum-generating algebra
The spectrum-generating algebra (SGA) for charged superstrings placed in constant background magnetic fields is constructed. Contrary to the neutral string this algebra is characteristic of including the cyclotron frequency. The Regge intercept and superconformal anomalies are calculated to be shifted by the cyclotron frequency and Dbrane parameters from the conventional values.
118270514
Covariant lagrangian formulation of interacting heterotic strings
A manifestly Lorentz-covarariant lagrangian formulation of the Neveu-Schwarz-Ramond heterotic string interacting with external fields is presented. The action is derived from the action for fully 26-dimensional semi-superstring by a simple ansatz. The internal space compactification occurs automatically from the action. The twist factors associated with the Kac-Moody algebra are involved in the theory without introducing them by hands.
16459641
Interaction between Noncommutative Open Strings and Closed-String Tachyons
We construct a vertex operator that describes the emission of a ground-state tachyon of a closedstring out of a noncommutative open string. Such a vertex operator is shown to exist only when the momentum of the closed-string tachyon is subject to some constraints coming from the background B field. When the non-zero background B fieldis lying only on a D-brane, and both ends of the open string are on the D-brane, the closed-string tachyon is emittedfrom the open string in an orthogonal d irection to the D-brane. The vertex operator has a multiplicative coupling constant g(σ) which depends on σ as g(σ) = sin 2 σ in 0 ≤ σ ≤ π. This behavior is the same as in the ordinary B = 0 case.
199683835
Energy Resolution and Rise Time of HPGe Detectors in High Magnetic Fields
120181374
The study of hypernuclei with heavy ion beams at GSI
The international HypHI collaboration is proposing a hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron/proton rich hypernuclei and eventually to measure hypernuclear magnetic moments. As Phase 0 of the HypHI project, we propose the feasibility study of heavy ion induced hypernuclear spectroscopy by observing a mesonic weak decay from H Λ 3 , H Λ 4 and He Λ 5 with 6Li beams at 2 A GeV impinging on a 12C target. The physics motivations, experimental setup and the expected results will be discussed.
15509349
Performance of hpge detectors in high magnetic fields
Abstract A new generation of high-resolution hypernuclear γ -spectroscopy experiments with high-purity germanium detectors (HPGe) are presently designed at the FINUDA spectrometer at DA Φ NE, the Frascati φ -factory, and at P ¯ ANDA , the p ¯ p hadron spectrometer at the future FAIR facility. Both, the FINUDA and P ¯ ANDA  spectrometers are built around the target region covering a large solid angle. To maximise the detection efficiency the HPGe detectors have to be located near the target, and therefore they have to be operated in strong magnetic fields ( B ≈ 1 T ). The performance of HPGe detectors in such an environment has not been well investigated so far. In the present work VEGA and EUROBALL Cluster HPGe detectors were tested in the field provided by the ALADiN magnet at GSI. No significant degradation of the energy resolution was found, and a change in the rise time distribution of the pulses from preamplifiers was observed. A correlation between rise time and pulse height was observed and is used to correct the measured energy, recovering the energy resolution almost completely. Moreover, no problems in the electronics due to the magnetic field were observed.
53994621
RISING: Gamma‐ray Spectroscopy with Radioactive Beams at GSI
The Rare Isotope Spectroscopic INvestigation at GSI (RISING) project is a major pan‐European collaboration. Its physics aims are the studies of exotic nuclear matter with abnormal proton‐to‐neutron ratios compared with naturally occurring isotopes. RISING combines the FRagment Separator (FRS) which allows relativistic energies and projectile fragmentation reactions with EUROBALL Ge Cluster detectors for γ spectroscopic research. The RISING setup can be used in two different configurations. Either the nuclei of interest are investigated after being stopped or the heavy ions hit a secondary target at relativistic energies and the thereby occurring excitations are studied. For the latter case, MINIBALL Ge detectors and the HECTOR array are used in addition. Example achievements of the Fast Beam setup are presented and compared to various shell model calculations, while for the Stopped Beam setup initial results are shown.
122641390
The T=2 mirrors 36Ca and 36S: A test for isospin symmetry of shell gaps at the driplines
The first excited 2 + state of 36 Ca has been identified by its γ -decay, exploiting the two-step fragmentation technique at the FRS-RISING setup at GSI. This is the heaviest Tz =− 2 nucleus in the Segre chart in which a γ -decay of an excited state has been observed. A stable beam of 40 Ca at 420A MeV impinged on a primary 9 Be target. Out of the secondary beam of fragmentation products, 37 Ca was separated by the FRS and struck on a second 9 Be target at the final focus of the FRS. The energy for the 2 + decay of 36 Ca was determined to be 3015(16) keV, which is 276 keV lower than in its T = 2 mirror 36 S. This mirror energy difference (MED) is discussed in the framework of shell model calculations using a 16 O core, the sd shell isospin symmetric interaction USD and experimental single-particle energies from 17 Oa nd 17 F. The results show that the MED within the sd shell provide a sensitive test for the evolution of the N , Z = 14, 16 subshell gaps towards the driplines. Especially the N, Z = 16 gap is determined by Thomas–Ehrman shift in the A = 17, T = 1/2 isospin doublet, while Coulomb effects are found to have marginal influence. © 2007 Elsevier B.V. All rights reserved.