16734475
Constrained Quantization of Charged Strings in a Background B Field and g-Factors
The Dirac quantization is performed for the constrained system of the open string with different charges located at both ends in the constant background B field. Noncommutativity reveals to commutators [X, X], [P, P] and also [X,P] at both ends of the string. We consider a dependence on the change of the "cyclotron frequency" of the charged string. The g-factor of the charged string is also calculated in the framework of our formulation.
121289650
Schwarzian Connections in the Krichever-Novikov Algebra
In the local operator approach to higher-genus Riemann surface we point out an importance of
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
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.
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.
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.